Creagrutus beni Eigenmann 1911

aquarium: commercial

Creagrutus beni

Creagrutus bolivari Schultz, 1944:334, fig. 49, tabs. 22, 23 [type locality: Venezuela, Estado de Aragua, Río Guárico and tributaries between San Sebastián and San Casimiro].—Myers and Roberts, 1967:249 [C. bolivari as a possible synonymy of C. phasma Myers, 1927].—Mago-Leccia, 1970:70 [footnote; C. bolivari as a possible synonym of C. phasma, following Myers and Roberts, 1967].—Fowler, 1975:26 [in list of nominal Creagrutus species].—Géry and Renno, 1989:3 [as a possible synonym of C. phasma].—Vari and Howe, 1991:15 [location of type specimens].—Taphorn, 1992:170, figs. 40a, 109, 110 [occurrence in Río Apure system, Venezuela; ecology, common name].—Machado-Allison and Moreno, 1993:85–94, tabs. 1, 2, 5, 7 [ecology and distribution in Venezuela, Estado Guarico, Río Orituco].—Machado-Allison et al., 1993:66, 69 [Venezuela, Ríos Aguaro and Guariquito; ecology].—Machado-Allison et al., 1993:133 [Venezuela: low Llanos of Río Orinoco basin].—Taphorn et al., 1997:71 [cited for Venezuela].—Marrero et al., 1997:76 [rivers of Llanos of Venezuela].

DIAGNOSIS.—The combination of the possession of premaxillary dentition arranged in the three components generalized for most of the species of Creagrutus and Piabina without a distinctly larger gap between the first and second teeth of the primary series, 2 to 4 teeth on the maxilla, 6, rarely 5, teeth in the primary tooth row of the premaxilla, 5 dentary teeth, 37 to 40 lateral line scales without a lamellar process over each pore, 8 to 10 predorsal scales, 4 scale rows between the dorsal-fin origin and the lateral line, 35 to 37 vertebrae, 8 to 10 branched anal-fin rays, 2 post-anal median scales to the anal-fin origin, the distance from the snout to the dorsal-fin origin (45.0%–50.3% of SL), the bony orbital diameter (28.2%–36.6% of HL), the interorbital width (28.0%–33.3% of HL), the 5 to 9 gill rakers on the upper limb and 9 to 12 gill rakers on the lower limb of the first arch, the moderately developed third infraorbital whose ventral margin falls distinctly short of horizontal limb of preopercle, the lack of a series of dark midlateral spots on the body, the humeral mark in the form of a vertically elongate bar of nearly uniform width, and the absence of a discrete patch of dark pigmentation on the middle portion of the anterior dorsal-fin rays distinguishes Creagrutus bolivari within the clade composed of Creagrutus and Piabina.

DESCRIPTION.—Morphometric and meristic data for Creagrutus bolivari in Table 10. Body relatively deep and compressed. Greatest body depth at, or immediately anterior of, dorsal-fin origin. Dorsal profile of head distinctly convex from margin of upper lip to vertical through posterior margin of posterior nares, straight from that point to posterior tip of supraoccipital spine. Dorsal profile of body slightly and symmetrically convex to dorsal-fin origin, straight to slightly concave from that point to base of adipose fin, slightly concave from rear of adipose-fin base to caudal-fin base. Ventral profile of head with obtuse angle approximately midway between margin of lower lip and posterior of dentary, straight to slightly convex from that angle approximately to pectoral-fin insertion; slightly convex between pectoral- and pelvic-fin insertions; slightly concave from anal-fin origin to caudal peduncle.

Upper jaw longer than, and overhanging, lower jaw. Anterior portion of snout quite fleshy, with many minute papillae on anteromedial portion of snout, papillae continuing ventrally onto upper lip and into mouth on fleshy flaps between premaxillary teeth. Lower lip distinctly fleshy anteriorly, with papillae concentrated on lip and decreasing in number ventrally and laterally; papillae also present on isthmus.

Infraorbital series relatively poorly developed, with ventral margin of third infraorbital distinctly separated from horizontal and vertical limbs of preopercle, gap between posterior margin of third infraorbital and vertical limb of preopercle at most one-third width of orbit; posterior and ventral margins of third infraorbital distinctly and smoothly curved. Posterior margins of fourth and fifth infraorbitals vertical and distinctly separated from vertical limb of preopercle by broad gap equal to approximately one-half of width of fourth infraorbital.

Premaxillary dentition in three series: primary row slightly curved, without pronounced gap between first and second tooth of series, typically with 6 teeth, although rarely 5 teeth, present on one premaxilla, and 7 teeth present on both premaxillae in one specimen; triangular cluster of 3 larger teeth with posteromedial tooth distinctly larger; and single tooth of form similar to that of primary series typically lying lateral to fourth tooth of primary row, or lateral to region where fourth and fifth teeth of that row contact. Maxilla with 2 to 4 tricuspidate teeth. Dentary with 5 tricuspidate teeth; second largest, about one and one-half times size of first tooth and twice height of third tooth but much more massive. Fourth and fifth dentary teeth distinctly smaller than third tooth in series.

Dorsal-fin rays ii,8. Dorsal-fin origin located anterior of vertical through pelvic-fin insertion by distance equal to width of one or two midlateral scale rows. Distal margin of dorsal fin slightly concave, with slightly elongate anterior lobe. Anal-fin rays ii,8–10 or iii,8–10. Anal fin with hooks, when present, on segments of first branched ray of mature males (first two rays in 1 out of 5 hook-bearing specimens). Distal margin of anal fin slightly to markedly sinusoidal, with elongate anterior lobe followed by concavity. Pectoral-fin rays i,10–12. Pectoral fin relatively short, tip not extending to pelvic-fin insertion. Pelvic-fin rays i,6,i or i,7. Tip of pelvic fin approaching or extending to anteriormost unbranched anal-fin ray. Mature males with pelvic-fin hooks on segmented and unsegmented portions of all 7 branched rays or 6 branched rays and on medial unbranched ray.

Gill rakers 5–9+9–12.

COLORATION IN ALCOHOL.—Dorsal surface of head with uniform diffuse pattern of small, dark chromatophores, larger and darker chromatophores present on lateral portions of frontals and on dorsal surface of brain. Smaller dark chromatophores continuing anteriorly onto snout. Distinct small crescent of dark chromatophores immediately in front of anterior nares. Band of scattered, dark chromatophores extending from posterior wall of nares around ventral and posterior margin of orbit, and forming dense patch located anteroventral to eye. Pigmentation on ventral surface of head restricted to transverse band of small, dark chromatophores on lower lip. Pigmentation on lateral surface of head confined to widely scattered, large, light to dark brown chromatophores on dorsalmost portion of cheek and area covering upper portions of infraorbital series and opercle. Body with pigmentation most concentrated dorsally, particularly at dorsal-fin base and in narrow middorsal band extending from dorsal-fin base to procurrent caudal-fin rays, and over center of exposed surface of scales on dorsolateral surface of body. Humeral mark in form of vertically elongate bar of approximately uniform width with one-fourth of its length ventral of lateral line and remainder dorsal of that structure. Pigmentation in mark most concentrated immediately dorsal of lateral line. Overall form of humeral mark relatively straight ventrally and extending towards center of pectoral-fin base; dorsal portion of mark with distinctive anterior concavity and extending towards third or fourth predorsal scale. Humeral bar diffuse in smaller specimens, becoming vertically elongate between 23 and 27 mm SL. Little or no dark pigmentation on body ventral to lateral line. Some individuals with small, dark chromatophores delineating myosepta in region immediately dorsal to anal fin. Variably distinct predorsal stripe present; stripe formed by deep-lying, stellate, dark chromatophores. Chromatophores most concentrated anteriorly near supraoccipital spine in some specimens. Midlateral stripe located entirely above lateral line except on caudal peduncle, becoming denser posteriorly and expanding slightly over hypurals.

Caudal-fin membranes invested with dark pigmentation delineating rays, pigmentation darkest on ventral lobe and especially concentrated on central fin-rays; entire distal margin of caudal fin with a band of small, dark chromatophores. Unbranched anal-fin rays unpigmented, anterior margins of branched rays delineated by dark pigmentation. Dorsal fin with patch of dark pigmentation covering distal one-half of last unbranched and two anterior branched rays, becoming narrower and confined to fin margin posteriorly; seventh and eight branched rays unpigmented. Pectoral fin with scattered, large, light brown chromatophores. Pelvic fin unpigmented.

ECOLOGY.—Taphorn (1992:171) summarized the conditions inhabited by Creagrutus bolivari as “flowing waters” over rocky substrates in the Andean piedmont and the Llanos (savannahs) of the Río Orinoco basin. The diet of the species consists of drifting or benthic organisms. Creagrutus bolivari is moderately abundant in portions of the Río Orituco system in the central portion of its range (Machado-Allison and Moreno, 1993). Ortaz (1997:1147) reported on the reproductive cycle of a species cited as Creagrutus bolivari from the Río Orituco in north central Venezuela. That author utilized Schultz (1944) and Géry (1977) as the basis for that identification. Unfortunately the keys provided by those two authors do not discriminate C. bolivari from the two other species that occur in the Río Orituco basin, C. melasma and C. taphorni. It is therefore impossible to ascertain which of the three species was studied by Ortaz (1997). In the western portions of its range C. bolivari was captured together with C. atratus.

COMMON NAME.—Venezuela, Río Apure system: “Dientefrio, buck-toothed tetra” (Taphorn, 1992:171).

DISTRIBUTION.—Creagrutus bolivari is widely distributed in an arc across the Río Orinoco basin from the Río Metica, which is a component of the Río Meta basin in Colombia in the west, through northern Venezuela, to somewhere within Estado de Monagas, Venezuela, in the east (Figure 28, stars; exact coordinates of the Estado de Monagas record could not be determined).

COMPARISONS.—Creagrutus bolivari is a quite distinctive species with a steeply sloping predorsal region of the body and an elongate, arcuate humeral bar; these attributes were well represented in the original description (Schultz, 1944:334). The distribution of the species overlaps those of a number of its congeners in the main portion of the Orinoco basin, but it can be readily distinguished by the just-cited characters and the features noted in “Key to Species of Creagrutus in the Río Orinoco Basin.”

GEOGRAPHIC VARIATION.—Population samples of Creagrutus bolivari examined during this study mostly originated in the central and eastern portions of the Río Orinoco basin in Venezuela (Figure 28). A series of samples from the upper portions of the Río Meta basin in the western portions of the basin in Colombia also are identified herein as C. bolivari as they agree with the more eastern samples in all meristic and morphometric features, other than for having a shift in the range of the total number of vertebrae. Within the central and eastern portions of the Orinoco basin, C. bolivari has 35 to 38, rarely 38, vertebrae, whereas the Colombian population samples have 36 to 38, typically 37 or 38, vertebrae. Further collections from intervening areas are necessary to determine whether this variation demonstrates any discrete pattern.

MATERIAL EXAMINED.—579 specimens (64, 26.3–61.0).

COLOMBIA. Río Roncador, E slope of Cordillera Oriental, E of Bogotá, CAS 69302, 2 (formerly IU 13179). Río Guadrigua, E slope of Cordillera Oriental, E of Bogotá, CAS 69301, 3 (formerly IU 13174). Meta: Río Metica, approximately 1.5 km E of Rajote (3°56′S, 73°03′W), ANSP 134160, 50 (9, 38.6–50.2). Río Meta basin, Río Ocoa, approximately 15 km E of Villavicencio, NRM 16847, 11 (6, 26.3–61.0). Río Meta basin, Ca˜no Union, tributary to Río Ocoa, where crossed by road between Villavicencio and Acacias, NRM 16844, 22 (29.4–54.7). Río Meta basin, Ca˜no Candelaria, tributary to Río Negro, approximately 20 km SW of Villavicencio, NRM 16846, 3. Río Meta basin, Río Manacasias, Restrepo, MHNG 2183.39, 4. Río Metica, approximately 3 km SE of Hacienda Mozambique (3°57′N, 73°02′W), ANSP 134081, 50.

VENEZUELA. Aragua: Río Carmen de Cura, 5 km SE of Carmen de Cura (latter locality at 9°48′N, 66°50′W), MHNLS 525, 21 (10, 36.7–44.4). Río Guárico and tributaries between San Sebastion and San Casimiro (latter locality at 10°00′N, 67°01′W), USNM 121497, 1 (50.2, holotype of Creagrutus bolivari), USNM 121498, 82 (paratypes of Creagrutus bolivari; 9, 35.7–48.3). Barinas: Río Santo Domingo, S of city of Barinas (approximately 8°38′N, 70°12′W), MCNG 7432, 9. Bolivar: Río Orocopiche, on road from Caicara to Ciudad Bolivar (approximately 8°07′N, 63°39′W), MBUCV V-18110, 5. Pools and beaches in front of Salto de Icutu, Río Nichare system, Río Caura basin (5°53′00″N, 64°51′W), MCNG 21492, 20 (5, 37.8–46.0). Río Matuanta, 12 km E of Ciudad Bolivar, MHNLS 518, 48. Río Cuchivero, at Cuchivero ferry crossing (7°29′N, 65°35′W), ANSP 159830, 43; MBUCV V-18065, 6 (2, 40.2–52.3). Río Cariapo, at bridge along highway from Caicara to Ciudad Bolivar (7°53′N, 63°49′42″W), MBUCV V-18037, 29; ANSP 159833, 1; ANSP 159831, 83. Guarico: Río Orituco, along road from Calabozo, below bridge, MBUCV V-21432, 3; MBUCV V-21449, 1. Río Orituco, bridge at road from Calabozo to Cazorla, MBUCV V-21933, 1. Río Orituco, 15 km SSE of Calabozo on Cazorla Road (8°48′N, 67°26′W), ANSP 139534, 3. Río Orituco, MBUCV V-21508, 4. Guariquito Creek, Río Orinoco basin, 6 km E of San Jose, INHS 69458, 4. Río San Jose on W boundary of Aquaro-Guariquito National Park, INHS 69530, 8. Monagas: Río Arco, MHNLS 9251, 2. Portuguesa: Río Bocono, in front of “Sun-Sun,” MBUCV V-8378, 8; USNM 327935, 2. Río Bocono, Puerto Sun-Sun, in front of port, MBUCV V-9464, 15. Río Ospino, at Ospino (9°18′N, 69°27′W), MBUCV V-8404, 3. Río Tucupido, immediately above junction with Río Guanare, just behind the Santuario de la Coromoto, approximately 1.7 km SW of Guanare (latter locality at 9°03′N, 69°45′W), just above junction with Río Guanare, UF 32318, 31.

The following lot, discussed above (see “Remarks”), is tentatively assigned to C. bolivari.

VENEZUELA. Monagas: Río Guarapiche, Caicara, USNM 163155, 1.

Creagrutus beni Eigenmann, 1911

Creagrutus beni Eigenmann, 1911:172, pl. 6: fig. 2 [type locality: Villa Bella on Rio Beni (=Bolivia, El Beni, Rio Beni, Villa Bella); not specimen from Cachoeira de Velha de Rio Nova, Brazil, cited in footnote]; 1927:421, pl. 58: fig. 3, pl. 93: fig. 4 [Bolivia (El Beni), Rio Beni, Villa Bella; not remaining cited specimens or reported distribution of species in Colombia and Venezuela; not pl. 93: figs. 5, 7].—Henn, 1928:63 [presence of holotype in Carnegie Museum].—Pearson, 1937b:108 [Bolivia, Rio Beni and Mamoré basins; not cited occurrence of species in Amazon basin outside Rio Beni system or citation of species in Rio Magdalena, Colombia].—Eigenmann and Allen, 1942:228 [Bolivia, Rio Beni; not listed specimens or cited distribution of species outside of Rio Beni basin].—Fowler, 1945a:148 [literature compilation; not citations for Rio Marañon, Peru, or cited distribution outside Bolivia]; 1948:83, fig. 88 [literature compilation; not citations of occurrence of species outside Bolivia]; 1975:26 [listing].—Géry, 1964:60 [in key, not cited occurrence of species in Peru, [Rio] Meta of Columbia, and Venezuela].—Terrazas-Urquidi, 1970:25 [listing in fishes of Bolivia].—Lauzanne and Loubens, 1985:110 [Bolivia: Rio Mamoré basin].—Ibarra and Stewart, 1987:28 [holotype depository].—Lauzanne et al., 1991:66 [Bolivia: Rio Chapare and Rio Boopi].—Not Eigenmann, 1920:12; 1921, pl. 93: fig. 7; 1922:238.—Not Pearse, 1920:12, 25, 43.—Not Fowler, 1931:408; 1942:134; 1943a:238, 1945b:102.—Not Pearson, 1937a:92.—Not Beebe, 1945:84; 1948:149.—Not Pozzi, 1945:270.—Not Fernández-Yépez, 1952: 43.—Not Luengo, 1963:326.—Not Mago-Leccia, 1967:233; 1970:70.—Not Géry, 1972:66.—Not Saul, 1975:106.—Not Cala, 1977:7.—Not Ortega and Vari, 1986:8.—Not Stewart et al., 1987:26.—Not Marrero and Machado-Allison, 1990:66.—Not Barriga, 1991:17.—Not Lowe-McConnell, 1991: 68.—Not Pavlov et al., 1995:233.

DIAGNOSIS.—The combination of the possession of premaxillary dentition arranged in the three components generalized for most of the species of Creagrutus and Piabina without a distinctly larger gap between the first and second teeth of the primary series, 6 (rarely 5) teeth in the primary tooth row of the premaxilla, 2 to 4 teeth on each maxilla, 6 teeth on each dentary, 38 to 42 lateral line scales without a lamellar process over each pore, 9 to 12 median predorsal scales, 3 or 4 rows of scales between the lateral line and the anal-fin origin, 2 post-anal scales to the anal-fin origin, 9 to 11 branched anal-fin rays, 6 or 7 gill rakers on the upper limb of the first gill arch, 8 to 10 gill rakers on the lower limb of the first gill arch, the distance from the snout to the pelvic-fin insertion (44.0%–47.8% of SL), the postorbital head length (44.6%–50.1% of HL), the bony orbital diameter (29.5%–32.7% of HL), the snout length (22.6%–28.9% of HL), the interorbital width (29.7%–32.7% of HL), the caudal peduncle depth (11.4%–12.9% of SL), the well-developed third infraorbital whose ventral margin approaches or contacts the horizontal limb of the preopercle, the lack of a series of dark spots along the midlateral surface of the body, the discrete, vertically elongate humeral mark, and the lack of a distinct patch of dark pigmentation on the middle portions of the anterior dorsal-fin rays distinguishes Creagrutus beni from all congeners with the exception of C. changae. Those two species can be discriminated by the number of dentary teeth (6 on each dentary in C. beni versus 5 in C. changae) and by differences in the bony orbital diameter (7.1%–8.4% of SL, less than horizontal distance from posterior margin of orbit to posterior margin of opercle in C. beni versus 8.7%–10.3% of SL, equaling or exceeding horizontal distance from posterior margin of orbit to posterior margin of opercle in C. changae).

Characters A B

Morphometrics

Standard length 40.4 33.6–73.3

1. Snout to anal-fin origin 61.0 59.8–66.2

2. Snout to pelvic-fin insertion 44.1 44.0–47.8

3. Snout to pectoral-fin insertion 21.3 21.2–26.0

4. Snout to dorsal-fin origin 46.7 46.6–50.7

5. Dorsal-fin origin to hypural joint 58.3 53.9–59.4

6. Dorsal-fin origin to anal-fin origin 34.5 29.9–34.7

7. Dorsal-fin origin to pelvic-fin insertion 30.0 27.1–30.7

8. Dorsal-fin origin to pectoral-fin insertion 31.9 32.0–35.9

9. Caudal peduncle depth 11.9 11.4–12.9

10. Pectoral-fin length – 18.4–22.1

11. Pelvic-fin length – 13.9–16.8

12. Dorsal-fin length – 20.1–25.1

13. Anal-fin length – 16.8–20.1

14. Head length 24.3 24.7–27.2

15. Postorbital head length 42.9 44.6–50.1

16. Snout length 26.5 22.6–28.9

17. Bony orbital diameter 36.7 29.5–32.7

18. Interorbital width 33.7 29.7–32.7

Meristics

Lateral line scales 39 38–42

Scale rows between dorsal-fin origin and lateral line 4 4–51

Scale rows between anal-fin origin and lateral line 3 3–4

Predorsal median scales 8? 9–12

Branched dorsal-fin rays 8 8

Branched anal-fin rays 11 9–11

Branched pelvic-fin rays – 5–72

Pectoral-fin rays – 12–14

Vertebrae 38 37–39

1Five scale rows between dorsal-fin origin and lateral line typical, 4 scales less common.

2Five branched pelvic-fin rays present in only one specimen.

DESCRIPTION.—Morphometric and meristic data for Creagrutus beni in Table 9. Head relatively robust in all specimens larger than 25 mm SL, body more robust anteriorly, more so in specimens larger than 30 mm SL. Greatest body depth at dorsal-fin origin in smaller specimens, shifted slightly anteriorly in some larger individuals. Dorsal profile of head smoothly convex from tip of snout to vertical through center of orbit in all specimens, profile from that point to rear of supraoccipital spine ranging from slightly convex to slightly concave. Predorsal profile continuous with that of head in smaller individuals, with variably evident change in alignment relative to that of head in larger specimens. Ventral profile of head ranging from smoothly convex to having variably obvious obtuse angle at anteroventral corner of dentary, angle typically more obvious in larger individuals. Ventral profile of body smoothly convex from isthmus to anal-fin origin, convexity usually more pronounced in larger individuals.

Head obtusely pointed in lateral view, but more compressed laterally from dorsal view. Upper jaw distinctly longer than, and overhanging, lower jaw. Anterior portion of snout somewhat fleshy, with numerous small papillae. Papillae more concentrated on fleshy upper lip, fleshy folds, and plicae extending between outer and medial premaxillary teeth, and on lateral surface of maxillae. Papillae also common in many specimens on dorsal margin of lower lip, with scattered papillae over ventral surface of lip.

Infraorbital series moderately developed. Third infraorbital variably developed, with ventral margin contacting, or nearly contacting, ventral limb of preopercle in some individuals, but falling short of that point in other specimens. Posterior margins of third through fifth infraorbitals falling distinctly short of vertical limb of preopercle (see under “Remarks,” below, concerning discrepancy in this feature between data in original species description and condition in putative holotype).

Premaxillary dentition in three series: primary row moderately curved, more so anteriorly, typically consisting of 6 teeth, with approximately 5% of specimens with only 5 teeth in series, without pronounced gap between first and second tooth of series but with medial tooth of series distinctly separated from matching tooth of contralateral series; triangular cluster of 3 teeth with posterolateral tooth somewhat larger and with medial teeth on contralateral clusters in contact; and single tooth of form similar to that of primary series lying lateral to fourth tooth of primary premaxillary series or lateral to space between third and fourth tooth of that series. Maxilla with 2 to 4, typically 3, teeth, teeth all tricuspidate or fourth tooth, when present, sometimes with straight distal margin. Dentary with 6 teeth; 3 anterior teeth distinctly larger and tricuspidate with middle cusp larger, middle cusp of third tooth posteriorly recurved; first and second teeth largest and subequal, larger than third; fourth to sixth teeth graded in size, tricuspidate or last tooth sometimes conical.

Dorsal-fin rays typically ii,8, iii,8 in one examined specimen with very short first unbranched ray. Dorsal-fin origin slightly posterior of vertical thorough pelvic-fin insertion. Profile of distal margin of dorsal fin straight in smaller specimens, becoming convex in larger individuals, with slight indication of anterior lobe. Anal-fin rays ii,9–11. Profile of distal margin of anal fin distinctly concave, with slightly developed anterior lobe. Mature males with hooks on last unbranched and anterior 3 to 6 branched anal-fin rays. Pectoral-fin rays i, 11–13. Pectoral fin extending posteriorly somewhat more than three-fourths of distance to pelvic-fin insertion. Pelvic-fin rays typically i,6,i; i,7 in approximately 15% of specimens, i,5,i in one individual. Mature males with pelvic-fin hooks present on all branched rays of some specimens and also on medial unbranched ray in one specimen. Tip of pelvic fin extending to anus.

Gill rakers 6–7 + 8–10.

COLORATION IN ALCOHOL.—Specimens retaining guanine on scales silvery, more so in region overlying midlateral body stripe and over lateral surface of head. Dorsal surface of head with field of small, dark chromatophores, more so posteriorly. Chromatophore field continuing anteriorly, but less concentrated over snout and upper lip. Region immediately anterior to nares with dark chromatophores somewhat more concentrated; chromatophore field in that region continuous with curved band of chromatophores ventral and posterior to orbit. Dorsal portions of infraorbital series and opercle with scattered, large, dark chromatophores.

Scales of dorsal portion of body with small, dark chromatophores concentrated over anterior portion of exposed section of scales and with band of dark chromatophores along posterior margin of scales. Two pigmented regions separated by hyaline crescent. Humeral mark well developed in all specimens larger than 25 mm SL, variably masked in specimens retaining guanine on scales; vertically elongate with slightly irregular borders, vertical extent of humeral mark greater in larger individuals. Intensity of pigmentation usually even across humeral mark, slightly less developed dorsally and ventrally in some individuals. Obscure midlateral body stripe formed by deep-lying and surface chromatophores extending from under dorsal fin to rear of caudal peduncle. Stripe vertically expanded on caudal peduncle, but not extending onto caudal-fin base.

Dorsal fin with margins of rays and membranes overlain with small dark chromatophores on distal two-thirds of fin; pigmentation most developed on anterior one-half of fin. Anal fin with anterior margins of rays outlined by series of small dark chromatophores, anterior rays with chromatophores extending over basal two-thirds of rays; extent of chromatophore series along rays becoming progressively reduced posteriorly. Anal-fin ray membranes with scattered, dark chromatophores, more so in larger individuals. Caudal-fin rays outlined by series of dark chromatophores. Pelvic and pectoral fins hyaline or with scattered, dark chromatophores.

ECOLOGY.—Little information is available about the ecology of Creagrutus beni, but examined specimens come from a noteworthy range of elevations. The type locality (Villa Bella on the Rio Beni) and other sites from which population samples are available, are at less than 200 m elevations, whereas some lots from the Department of Cochabamba and La Paz originated at sites of above 1000 m elevation.

A 55.0 mm SL female from the Rio Mamorè (MCNG 23913) was filled with numerous eggs. Mature males, as evidence by hooks on the anal and pelvic fins, are typically smaller than simultaneously collected, larger, presumably female, specimens.

DISTRIBUTION.—Creagrutus beni is endemic to the upper portions of the Rio Madeira system in northeastern Bolivia (Figure 28, squares).

MATERIAL EXAMINED.—161 specimens (60, 33.6–73.3).

BOLIVIA. El Beni: Villa Bella (10°23′S, 65°24′W), FMNH 54585, 1 (40.4, holotype of Creagrutus beni; formerly CM 3216). Río Mamoré, Laguna de Cristal Mayo (not located), MCNG 23913, 1 (55.0). Provincia Ballivian, Territorio Indigena Reserva de la Bíosfera Pilón-Lajas, mouth of Río Suapi (approximately 14°47′S, 67°38′W), 20 (15, 44.5–73.3). Provincia Ballivian, Río San Bernardo, at road from Yucumo to Rurrenbaque (approximately 13°38′S, 65°23′W), CBF 2366, 15 (9, 45.3–68.5). Provincia Cervado, Río Ibare, 5 km N of Puerto Almacén (latter locality at 14°53′S, 64°57′W), UF 82519, 1. Ox-bow lagoon approximately 96 m from Río Itenez, 9 km S of Costa Marques, Brazil (12°32′24″S, 64°12′42″W), UMMZ 204418, 5. Río Mamoré, Isla Nicolas Suarez, between Guayaramerin, Bolivia, and Guajará Mirim, Brazil (approximately 10°48′S, 65°23′W), AMNH 40189, 20. Cochabamba: Río Chapare basin, Villa Tunari (16°55′S, 65°22′W), MNHN 1989-1473, 5 (39.5–58.6); USNM 340959, 11 (6, 35.2–48.0; 2 specimens cleared and counterstained for cartilage and bone); MZUSP 27808, 5 (40.6–52.1); CBF 82, 3 (2, 51.3–55.1). Villa Tunari, Río Juntas de Caroni (approximately 16°55′S, 65°22′W), MCNG 23912, 3. Confluence of Río Chapare and Río Coni (approximately 16°51′S, 65°08′W), MHNG 2227.69, 1 (59.7). La Paz: Provincia Sud Yungas, upper Río Beni, at San Miguel de Huachi (15°40′S, 67°15′W), MHNG 2227.68, 1 (38.0). Provincia Sud Yungas, upper Río Beni, Río Boopi, San Miguel de Huachi (15°40′S, 67°15′W), CBF 59, 2 (60.4–67.9). Río Iniqui, tributary of Río Beni, approximately one-half distance between Huachi (?=San Miguel de Huachi) and Rurrenbaque, CAS 69287, 19 (5, 52.0–67.0). Provincia Iturralde, unnamed arroyo, 14 km W of Ixiamas (latter at 13°45′S, 68°09′W), CBF 02364, 3. Provincia Iturralde, Río Yariapu system of Río Beni basin, unnamed arroyo, 4 km S de Tumupasa (latter at 14°09′S, 67°55′W), CBF 2365, 6. Provincia Iturralde, Tumupasa (14°09′S, 67°55′W), USNM 86802, 15 (5, 45.0–54.8; formerly IU 17310, in part). Río Iniqui, upper Río Beni system, USNM 86840, 5 (formerly IU 17313, in part). Provincia Nor Yungas, Río San Miguel, upper Río Beni basin, Tomachi (15°26′S, 67°45′W), CBF 02361, 5. Río Popoi, upper Río Beni system, USNM 86771, 5 (2, 33.6–42.3; formerly IU 17311, in part). Río Colorado, lower Río Bopi system, USNM 86839, 5. Río Coroico, Caranavi, INHS 36969, 4.

Creagrutus beni

DIAGNOSIS.—The combination of the possession of premaxillary dentition arranged in the three components generalized for most of the species of Creagrutus and Piabina without a distinctly larger gap between the first and second teeth of the primary series, 2 to 5 teeth on the maxilla, 6 teeth in the primary tooth row of the premaxilla, 4 dentary teeth, 36 to 38 lateral line scales without a lamellar process over each pore, 9 to 11 predorsal median scales, 4 scale rows between the dorsal-fin origin and the lateral line, the lack of crenation on the scales of the posterior margin of many scales on the lateral surface of the body, 35 or 36 vertebrae, 10 to 12 branched anal-fin rays, 1 or 2 post-anal median scales to the anal-fin origin, the bony orbital diameter (23.3%–32.3% of HL), the postorbital length (46.7%–53.5% of HL), the poorly developed third infraorbital distinctly separated from the horizontal limb of the preopercle, the lack of a series of dark midlateral spots on the body, the humeral mark nearly vertical or slightly posterodorsally to anterodorsally inclined, the presence of a narrow medial predorsal line of dark pigmentation, and the absence of a discrete patch of dark pigmentation on the middle portion of the anterior dorsal-fin rays distinguishes Creagrutus lassoi within the clade composed of Creagrutus and Piabina.

DESCRIPTION.—Morphometric and meristic data for Creagrutus lassoi in Table 27. Body moderately deep and compressed. Greatest body depth ranging from slightly anterior of pelvic-fin insertion anteriorly as far as one-half of distance to pectoral-fin insertion. Large specimens much deeper and more compressed than smaller individuals. Dorsal profile of head distinctly convex from margin of upper lip to vertical between nares, straight from that point to rear of supraoccipital spine or with very slight concavity above eye. Dorsal profile of body slightly convex to dorsal-fin origin, inclination of predorsal region greatest in large specimens and in some individuals accentuated by hump-like inflection point immediately posterior to supraoccipital spine. Dorsal profile typically straight from dorsal-fin origin to caudal peduncle. Ventral profile of head with obtuse angle approximately midway between margin of lower lip and posterior of dentary, slightly to highly convex from that point approximately to pelvic-fin insertion; distinctly concave from anal-fin origin to caudal peduncle.

Upper jaw longer than, and overhanging, lower jaw. Anterior portion of snout quite fleshy, with many minute papillae on anteromedial portion of snout, papillae continuing ventrally onto upper lip and into mouth on fleshy flaps between premaxillary teeth. Continuous field of papillae covering most of head, evidently well developed in both sexes. Lower jaw distinctly fleshy anteriorly, with papillae most concentrated on lip and decreasing in number ventrolaterally, but extending posteroventrally in large numbers to isthmus and posteriorly over scales of anterior portion of abdomen.

Infraorbital series poorly developed, with ventral margin of third infraorbital rounded and roughly concentric with posteroventral margin of orbit. Ventral and posterior margins of third infraorbital separated from horizontal and vertical limbs of preopercle by gaps equal in width to approximately one-fourth of orbital diameter; large posteroventral gap approximately equal in width to diameter of pupil separates third infraorbital from inflection of preopercle. Posterior margins of fourth and fifth infraorbitals separated from vertical limb of preopercle by broad gap equal in width to approximately one-half that of respective infraorbital; gap slightly decreasing in width dorsally.

Premaxillary dentition in three series: primary row gently curved along line of premaxillary margin, without pronounced gap between first and second tooth of series, typically with 6 tricuspidate teeth, occasionally 5 teeth present on one premaxilla; anterior 4 teeth large and similarly developed, fifth and sixth teeth smaller with relatively reduced secondary cusps; triad of larger teeth with relatively prominent secondary cusps especially developed on posterior two teeth with posterolateral tooth largest; and single tooth of form similar to that of primary row lateral to fourth tooth of primary series. Maxilla with 2 to 5 tricuspidate teeth, 3 or 4 teeth most common. Dentary with 5 teeth, all tricuspidate except for conical last tooth in series; anterior two teeth largest with second tooth somewhat higher and distinctly wider than first tooth and more than twice as high as third tooth. Remaining dentary teeth becoming progressively smaller posteriorly.

Characters A B

Morphometrics

Standard length 47.5 40.5–75.4

1. Snout to anal-fin origin 61.7 59.5–66.9

2. Snout to pelvic-fin origin 44.4 41.9–51.1

3. Snout to pectoral-fin origin 26.5 24.4–27.3

4. Snout to dorsal-fin origin 51.6 47.5–53.6

5. Dorsal-fin origin to hypural joint 53.5 51.8–57.4

6. Dorsal-fin origin to anal-fin origin 31.2 28.9–34.1

7. Dorsal-fin origin to pelvic-fin insertion 31.6 27.4–33.1

8. Dorsal-fin origin to pectoral-fin insertion 37.7 33.9–40.1

9. Caudal peduncle depth 14.1 11.3–13.8

10. Pectoral-fin length 22.5 19.3–22.3

11. Pelvic-fin length 17.1 14.1–17.3

12. Dorsal-fin length 22.1 19.1–22.7

13. Anal-fin length 18.1 15.5–20.6

14. Head length 28.0 25.7–30.4

15. Postorbital head length 47.4 46.7–53.5

16. Snout length 27.1 26.5–33.5

17. Bony orbital diameter 31.6 23.3–32.3

18. Interorbital width 29.3 29.5–33.5

Meristics

Lateral line scales 37 36–38

Scale rows between dorsal-fin origin and lateral line 4 4

Scale rows between anal-fin origin and lateral line 3 3

Predorsal median scales 11 9–11

Branched dorsal-fin rays 8 7–8

Branched anal-fin rays 11 10–12

Branched pelvic-fin rays 7 7–81

Pectoral-fin rays 12 11–12

Vertebrae 36 35–36

1Eight branched pelvic-fin rays present in only 1 specimen.

Dorsal-fin rays ii,7 or 8. Dorsal-fin origin located at, to slightly posterior of, vertical through pelvic-fin insertion. Distal margin of dorsal fin slightly concave; elongation of anterior lobe barely noticeable. Anal-fin rays ii or iii, 10–12. Anal fin in mature males with hooks on segments of anterior two to four branched rays; hooks, if present on fourth ray, usually poorly developed. Distal margin of anal fin sinusoidal, with slightly elongate anterior lobe approximately twice as long as posteriormost branched ray. Pectoral-fin rays i,10 or 11. Tip of pectoral fin approaching or extending past pelvic-fin insertion. Pelvic-fin rays i,7, rarely i,8 or i,6,i. All pelvic-fin rays branched, except medial ray in most examined specimens (unbranched in 13 of 19 specimens). Tip of pelvic fin extending posteriorly to anal-fin origin in mature males, in other specimens fin-tip usually separated from anal-fin origin by distance equal to approximately one scale. Pelvic fin in mature males with hooks on segmented and unsegmented portions of all branched rays and medial ray if unbranched, some specimens with hook on both lateral and medial surfaces of segments, especially on medial three rays. Posterior margin of body scales slightly undulate to crenate; scale striae clearly visible.

Gill rakers 5–8 + 9–11.

COLORATION IN LIFE.—(Observations based on specimens from the Río Tupe, Estado de Yaracuy (MCNG 24685), fixed in formalin and stored in ethanol for three years but retaining some life colors). All unbranched and anterior two branched anal-fin rays, lateral unbranched and first branched pelvic-fin rays, and lateral pectoral-fin rays bright yellow. Both lobes of caudal fin bright yellow, pigmentation most intense in membranes associated with outer 2 or 3 rays; distal one-half of ventral caudal-fin lobe orange. Unbranched dorsal-fin rays yellow but pigmentation less intense than in other fins. Anterodorsal surface of eye orange-red, with overlying layer of reflective guanine.

COLORATION IN ALCOHOL.—Dorsal surface of head with diffuse pattern of small dark chromatophores continuing anteriorly onto snout and medial portions of upper jaw, with distinct small crescent of dark chromatophores immediately in front of anterior nares; pattern of chromatophores more irregular and diffuse laterally proximal to eye. Band of scattered, dark chromatophores extending from snout onto dorsal surface of cheek and continuing around posterior margin of orbit; noticeable concentration of pigmentation anteroventral of eye. Lateral surface of head with scattered stellate chromatophores on dorsal one-half of cheek and covering area behind eye and upper one-half of opercle; remainder of head without pronounced pigmentation pattern.

Body with pigmentation most concentrated dorsally, particularly at dorsal-fin base and below center of exposed surface of scales in broad, vertical, anteriorly concave band; extreme posterior margins of scales outlined by fine, dark pigment. Middorsal stripe, especially visible in mature males, consisting of concentrated dark chromatophores present below scales on anterior one-half of middorsal region and between bases of dorsal and adipose fins. Humeral mark most highly pigmented immediately dorsal of lateral line, extending ventrally one scale row below lateral line and dorsally three rows; overall form of mark bar-like, ranging from vertical to somewhat posterodorsally to anteroventrally oblique. Bar somewhat diffuse in large specimens. Pigmentation on lateral surface of body, other than for that associated with humeral bar, restricted to area dorsal of lateral line except for weakly delineated myosepta dorsal of anal-fin base. Midlateral body stripe diffuse anteriorly, becoming more densely pigmented and somewhat wider posteriorly on caudal peduncle. Reflective guanine layer very well developed, especially in association with, and mostly masking, midlateral stripe.

Caudal-fin rays all delineated by dark pigment, pigmentation darkest on ventral one-half of fin; membranes of ventral one-half of fin covered with diffuse dark chromatophores and extending to distal margin. Unbranched anal-fin rays unpigmented, branched rays delineated by small, dark chromatophores, pigmentation especially developed basally where chromatophores slightly enlarged. Anterior portion of anal fin in some specimens with scattered, large, dark chromatophores on distal membranes. Dorsal-fin membrane and ray margins with many dark chromatophores, except near base and on last two branched rays where pigmentation poorly developed or absent. Pectoral-fin rays delineated by dark chromatophores along their medial surfaces. Pelvic fin hyaline.

ETYMOLOGY.—The specific name, lassoi, is in honor of Carlos A. Lasso of the Museo de Historia Natural La Salle, Caracas and the Asociación Amigos de Doñana, Seville, in recognition of his many contributions to our knowledge of the fishes of Venezuela and his assistance to the authors.

ECOLOGY.—Creagrutus lassoi is sympatric, and possibly syntopic, with C. lepidus in the Quebrada El Charal, Río Aroa system. The general habitat for this low elevation water body was described by Vari et al. (1993) and is repeated under “Ecology” in the C. lepidus account herein. Fernández-Yépez (1972) found C. lassoi (identified therein as C. beni) at three of the eleven collecting locations in the Río Yaracuy drainage. These collections also may have included C. taphorni because both forms were at that time included in the rather broad conception of C. beni applied by previous authors. Fernández-Yépez (1972, pl. 14) noted that C. lassoi (identified by that author as C. beni) inhabits clear waters and feeds on algae from submerged stones and logs.

COMMON NAME.—Venezuela: “Pico de Loro” (Fernández-Yépez, 1972, pl. 14).

DISTRIBUTION.—Creagrutus lassoi occurs only in the Río Aroa and Río Yaracuy systems, Caribbean versant drainages of north central Venezuela (Figure 51, square).

COMPARISONS.—Reflective guanine is highly developed on the lateral surfaces of the body in Creagrutus lassoi, a feature that distinguishes it from all other congeners in rivers of the Caribbean versant and through the Río Orinoco basin. Creagrutus lassoi occurs with C. lepidus in the Río Aroa system of the Carribean slope. The two species are readily distinguishable on the basis of pigmentation and overall body form (compare Figures 51 and 53). Creagrutus lassoi is distinguished from C. taphorni, a similar species from that region and with which it co-occurs in the Río Yaracuy, by the undulate to crenate posterior margins of midlateral scales and by the occasional presence of a hook on both the medial and lateral surface pelvic-ray segments, features absent in C. taphorni. Creagrutus crenatus is most similar to C. lassoi, especially with regard to meristics and fin-ray hook morphology. These two species differ in the straight posterior opercular margin in C. crenatus compared with the concave posterior opercular margin in C. lassoi, the modally higher number of branched anal-fin rays and lateral line scales in C. crenatus versus C. lassoi, and the crenate posterior scale margins, especially along the midlateral surface of the body in C. crenatus in comparison to the typically smooth scale margins in C. lassoi.

GEOGRAPHIC VARIATION.—Three specimens from the Río Mayorica, Río Yaracuy drainage (INHS 34937) that represent the only documented occurrence of C. lassoi outside of the adjacent Río Aroa drainage, have most of the diagnostic features of the species. The body in the Río Mayorica sample is proportionally a little shallower and less compressed, giving the specimens a slightly more rotund appearance. In addition, hooks observed on the pelvic rays are confined to the medial surface of the fin, a feature also observed in many of the smaller mature males from the Río Aroa drainage.

DISTRIBUTION.—Creagrutus lepidus is only known from the Rio Aroa and Rio Urama, Caribbean Sea versant drainages of northern Venezuela (Figure 51, square; see also “Remarks,” below).

COMPARISONS.—In addition to Creagrutus lepidus, only one other Creagrutus species, C. lassoi, is known from the Rio Aroa basin. The two species can be readily distinguished by the presence of a distinct, vertically elongate humeral mark in C. lassoi, which is absent in C. lepidus, and by the continuous midlateral stripe in C. lepidus, which contrasts with a midlateral stripe limited to the posterior one-half to two-thirds of the body in C. lassoi. Creagrutus lepidus is the only member of the genus known from the Rio Urama system.

MATERIAL EXAMINED.—51 specimens (46, 24.5–47.1).

VENEZUELA. Yaracuy: Sierra de Aroa, Rio Aroa basin, Finca El Jaguar, Quebrada El Charal (approximately 10°32′N, 68°32′W), MHNLS 9659, 1 (37.9, holotype of Creagrutus lepidus); MHNLS 4144, 12 (27.8–39.2, paratypes of Creagrutus lepidus); MBUCV V-23560, 12 (24.5–37.8; paratypes of Creagrutus lepidus); USNM 325045, 10 (25.7–42.4; paratypes of Creagrutus lepidus; 2 specimens cleared and counterstained for cartilage and bone); CAS 79520, 7 (26.3–40.1; paratypes of Creagrutus lepidus); MHNLS 4715, 5 (paratypes of Creagrutus lepidus). Carabobo: Quebrada Aqua Clara, tributary of Rio Urama (latter locality at 10°35′N, 69°16′W), MTD F 17701–17704, 4 (38.1–47.1).

Creagrutus beni [Venezuela: only Rio Guaire record, IU 15124 (=CAS 69290)]; 1927:422

Creagrutus cf. beni.—Taphorn. 1992:167 [in part, upper Rio Apure drainage only].

DIAGNOSIS.—The combination of the possession of premaxillary dentition arranged in the three components generalized for most of the species of Creagrutus and Piabina without a distinctly larger gap between the first and second teeth of the primary series, 3 to 5 teeth on the maxilla, 6 teeth in the primary tooth row of the premaxilla, 5 dentary teeth, 36 to 38 lateral line scales without a lamellar process over each pore, 9 to 13 predorsal median scales, 4 or 5 scale rows between the dorsal-fin origin and the lateral line, 36 or 37 vertebrae, 10 to 12 branched anal-fin rays, 2 post-anal median scales to the anal- fin origin, 13 or 14 gill rakers on the lower limb of the first gill-arch, the distance from the dorsal-fin origin to the anal-fin origin (29.2%–33.3% of SL), the distance from the dorsal-fin origin to the pelvic-fin insertion (28.3%–32.1 % of SL), the postorbital head length (42.5%–51.9% of HL), the bony orbital diameter (26.4%–32.8% of HL), the interorbital width (28.6%–35.4% of HL), the moderately developed third infraorbital with its ventral margin approaching or contacting the horizontal limb of the preopercle, the lack of a series of dark mid- lateral spots on the body, a vertical or slightly anterodorsally inclined humeral mark, and the absence of a discrete patch of dark pigmentation on the middle portion of the anterior dorsal- fin rays distinguishes Creagrutus taphorni within the clade composed of Creagrutus and Piabina.

Characters A B

Morphometrics

Standard length 52.5 45.6–74.1

1. Snout to anal-fin origin 61.5 61.5–65.1

2. Snout to pelvic-fin origin 44.8 44.2–47.4

3. Snout to pectoral-fin origin 25.1 24.2–26.7

4. Snout to dorsal-fin origin 49.3 47.8–51.4

5. Dorsal-fin origin to hypural joint 56.0 53.6–58.2

6. Dorsal-fin origin to anal-fin origin 33.0 29.2–33.3

7. Dorsal-fin origin to pelvic-fin insertion 30.5 28.3–32.1

8. Dorsal-fin origin to pectoral-fin insertion 35.4 33.5–38.2

9. Caudal peduncle depth 13.1 11.8–13.7

10. Pectoral-fin length 20.8 17.5–22.1

11. Pelvic-fin length 15.4 14.5–16.8

12. Dorsal-fin length 24.6 19.8–23.9

13. Anal-fin length 18.5 14.8–20.1

14. Head length 25.0 25.3–28.1

15. Postorbital head length 49.6 45.2–51.9

16. Snout length 26.7 25.0–34.0

17. Bony orbital diameter 30.5 26.4–32.8

18. Interorbital width 32.1 28.6–35.4

Meristics

Lateral line scales 37 36–38

Scale rows between dorsal-fin origin and lateral line 4 4–5

Scale rows between anal-fin origin and lateral line 3 3–4

Predorsal median scales 10 9–13

Branched dorsal-fin rays 8 8

Branched anal-fin rays 10 10–12

Branched pelvic-fin rays 7 6–7

Pectoral fin rays 13 11–13

Vertebrae 36 36–37

DESCRIPTION.—Morphometric and meristic data for Creagrutus taphorni in Table 54. Body moderately deep and transversely compressed. Greatest body depth ranging from slightly anterior of pelvic-fin insertion to anteriorly as far as one-half of distance to vertical through pectoral-fin insertion. Dorsal profile of head distinctly convex from margin of upper lip to vertical through posterior margin of posterior nares, straight from that point to rear of supraoccipital spine. Predorsal profile slightly convex to dorsal-fin origin. Body profile typically straight from posterior of dorsal-fin base to caudal peduncle, some specimens with slight concavity between bases of dorsal and adipose fins. Ventral profile of head with variably obvious obtuse angle approximately midway between margin of lower lip and posterior of dentary, straight to slightly convex from that point approximately to pelvic-fin insertion; slightly concave from anal-fin origin to caudal peduncle.

Upper jaw longer than, and overhanging, lower jaw. Anterior portion of snout quite fleshy, with many minute papillae on anteromedial portion of snout, papillae continuing ventrally onto upper lip and into mouth on fleshy flaps between premaxillary teeth. Lower lip distinctly fleshy anteriorly, with papillae concentrated on dorsal surface of lip. Papillae decreasing in number ventrally and laterally, extending ventrally and posteriorly in small numbers nearly to isthmus.

Infraorbital series moderately developed, occupying approximately two-thirds of cheek. Ventral margin of third infraorbital approaching or contacting ventral limb of preopercle. Posterior margin of third infraorbital distinctly separated from vertical limb of preopercle by space of at most one-fourth width of orbit. Posteroventral corner of bone broadly rounded, with posterior and ventral margins of third infraorbital approximately perpendicular to each other.

Premaxillary dentition in three series: primary row typically consisting of 6 teeth, 5 teeth present on 1 premaxilla of 1 specimen, teeth of primary series arranged in sigmoid pattern without pronounced gap between first and second tooth of series; cluster of 3 larger teeth lying medial to primary series with 2 posterior teeth larger; and single tooth of form similar to that of primary series lying lateral to fourth tooth of primary series. Maxilla usually with 3 or 4, occasionally 5, tricuspidate teeth. Dentary with 5 tricuspidate teeth, or with final tooth in series with only central cusp distinct. First and second dentary teeth distinctly larger than rest of series, with second tooth somewhat larger than first tooth and twice height of, and much larger overall than, third tooth. Remaining dentary teeth progressively decreasing in size posteriorly.

Dorsal-fin rays ii,8. Dorsal-fin origin located at vertical through pelvic-fin insertion. Distal margin of dorsal fin slightly concave, with noticeably elongate anterior lobe. Anal-fin rays ii, 10–12 or iii, 10–12. Mature males with anal-fin hooks on segments of first 3 to 5 branched rays. Distal margin of anal fin slightly sinusoidal. Pectoral-fin rays i, 10–12; Tip of pectoral fin approaching, or reaching to, pelvic-fin insertion. Pelvic-fin rays i,6, less commonly i,7 (note: i,8 found on one pelvic fin in one specimen from Estado de Miranda, Río Guiare, MBUCV V-21244, which may represent a developmental abnormality). Tip of pelvic fin typically extending posteriorly nearly to anal-fin origin. Mature males with pelvic-fin hooks on medial surface of segmented and unsegmented portions of basal shaft and medial branches of all seven branched rays.

Gill rakers 6–8 + 9–11.

COLORATION IN LIFE.—(The following observations are based on the examination of specimens (MCNG 28752) from the Río Bocanó, Portuguesa, Venezuela, made less than 24 hours after their capture and fixation in formalin). All unbranched and anterior 1 or 2 branched rays of dorsal, anal, and pelvic fins pale yellow basally, fading nearly to white distally. Dorsal, anal, and pelvic fins with striking, nearly white, leading edge. Caudal-fin rays pale yellow with yellow color most intense on ventral lobe, becoming orange in distal one-fourth of fin. Distal margin of caudal fin with narrow black band. Pale orange middorsal stripe present, coloration most intense in region between rear of head and area lateral to dorsal-fin base. Anterodorsal surface of eye orange-red, overlying reflective guanine pigment.

Beebe's description (1948:149) of life coloration of specimens from Rancho Grande, Aragua state (identified by that author as C. beni), agreed with the above description, although that author noted that in life the species has the “distal portion [of the caudal fin], especially under lobe, pink, varying to scarlet in some individuals” and has the “distal parts of pelvic and anal rays yellow.”

COLORATION IN ALCOHOL.—Dorsal surface of head with uniform diffuse pattern of dark chromatophores continuing anteriorly onto snout, with distinct small crescent-shaped patch of dark chromatophores immediately in front of anterior nares. Band of scattered, dark chromatophores extending from diffuse pigmentation on dorsal surface of snout posteroventrally to anteroventral margin of orbit, narrowing and continuing around posterior margin of orbit. Infraorbitals posterior of orbit and dorsal portion of opercle with scattered, large, dark chromatophores, more so in larger individuals.

Body with dark pigmentation most concentrated dorsally, particularly at dorsal-fin base and over center of exposed surface of scales. Many specimens with dark pigmentation along posterior margins of scales on dorsal portion of body, with darker pigmentation forming irregular reticulate pattern most obvious in larger, more darkly pigmented specimens. Narrow dark middorsal stripe present, most intense anterior of dorsal fin. Humeral mark with dark pigmentation most concentrated in region immediately dorsal of lateral line. Less concentrated field of chromatophores extending from intensely pigmented region towards pectoral-fin origin as ventrally attenuating patch of variably sized chromatophores. Humeral mark extending dorsally from central region as less intensely pigmented patch to approximately one-half of distance to middorsal line. Overall form of bar variable, ranging from slightly anterodorsally to slightly posterodorsally inclined bar. Dark pigmentation on lateral surface of body, other than humeral bar, restricted to area dorsal of lateral line in some individuals. Midlateral dark stripe beginning several scales posterior of humeral mark, becoming denser and somewhat wider posteriorly on caudal peduncle.

Dorsal-fin membrane with dark chromatophores most concentrated on central portion of fin. Unbranched anal-fin rays unpigmented, branched anal-fin rays delineated by series of small, dark chromatophores. Caudal fin with all fin rays delineated by dark pigment, pigmentation darkest on central rays of fin, particularly basally. Pectoral-fin rays delineated by dark chromatophores. Pelvic fin hyaline.

ETYMOLOGY.—The species name, taphorni, is in acknowledgment of Donald C. Taphorn, Museu de Ciencias Naturales, Guanare, Venezuela, who collected much of the material of the species and in recognition of his contributions to our knowledge of the fishes of the Llanos of the Orinoco basin and his assistance to the authors in this and other projects.

ECOLOGY.—According to Beebe (1948:149), C. taphorni (identified by that author as C. beni) was collected in streams in montane cloud forest. Creagrutus taphorni was collected with C. melasma on several occasions in the Rio Cojedas basin of the western portion of its geographic range and in the Río Orituco in the east.

Stomach contents of two specimens of Creagrutus taphorni examined by Beebe (1948; identified by that author as C. beni) consisted of firefly larvae, caterpillars, beetles, and undetermined adult and larval insects. Ortaz (1992:552) reported C. beni from the Río Limon, Parque Nacional Henri Pittier in northern Venezuela; however, that species is endemic to the upper Rio Madeira system in Bolivia, which is far distant from the Río Limon. Two Creagrutus species are known from the Río Limon basin, C. melasma and C. taphorni. The maximum size of the specimens examined by Ortaz (1992:552) was 80.05 mm SL, a length significantly larger than that for any examined specimen of C. melasma, but falling within the range of examined material of C. taphorni. Ortaz' record is thus considered to refer to C. taphorni. Ortaz (1992:552–553) reported that the species feeds mostly on various aquatic insects, with a number of families of dipterans represented in the diets. Various seeds and parts of flowers also were represented in the stomach contents of his sample.

COMMON NAME.—Venezuela: “Dientefrio,” “buck-toothed tetra” (Taphorn, 1992:167).

DISTRIBUTION.—Creagrutus taphorni is known from piedmont streams of north central Venezuela, east of the Andean Cordilleras, mostly in the Río Orinoco basin and the Río Tuy basin of the Caribbean versant (Figure 83, filled stars). The pattern of distribution is approximately congruent with the western portion of the range of C. melasma, which occurs from Estado Tachira in the southwest to Yaracuy in the northeast and eastward to the Río Orituco, Estado Guarico (Figure 59, stars).

GEOGRAPHIC VARIATION.—Double-hooked pelvic rays and crenate scale margins occur in a sample from the Río Valle, Distrito Federal, Venezuela (see Creagrutus cf. taphorni, USNM 121500 under “Material Examined”). These characters were otherwise observed only in C. lassoi, a species endemic to the Río Aroa, and in C. crenatus, which is known only from the Río Tocuyo system. Both of these drainages are within the Caribbean Sea versant of northern Venezuela. All the other features of this sample (USNM 121500) are otherwise in agreement with those of samples ascribed herein to C. taphorni, and for that reason the Río Valle samples are equated with that species.

MATERIAL EXAMINED.—1015 specimens (32, 40.7–74.1).

HOLOTYPE.—VENEZUELA. Guarico: Río Orituco, Parque Nacional Guatopo, first bridge along road from Santa Teresa to Altagracia, collected by H. Moreno and A. Machado-Allison, 20 May 1992, MBUCV V-29288 (52.5).

PARATYPES.—81 specimens (23, 45.6–74.1).

VENEZUELA. Aragua: Quebrada Agua Fria, Río Tuy system, approximately 1 km from its mouth in Río Tuy, collected by R. Royero et al., 6 Apr 1991, MBUCV V-21032, 10 (2, 45.6–51.6). Guarico: Río Orituco, Parque Nacional Guatopo, first bridge along road from Santa Teresa to Altagracia, collected with holotype, MBUCV V-29289, 5 (46.3–63.6). Miranda: El Amoladero, Río Guiare, R. Royero et al., 1 Jun 1991, MBUCV V-21244, 18 (8, 46.5–67.9); USNM 357730, 2 (50.7–51.1; specimens cleared and counterstained for cartilage and bone). Río Araira, upper portion, near Quebrada Las Pailes (approximately 10°37′N, 66°59′W), USNM 357784, 6 (55.2–74.1). Portuguesa: Distrito Guanare, Río Boconó, caño below entrance to Boconó Dam (8°1′50″N, 70°52′34″W), collected by D.C. Taphorn et al., 31 Jul 1993, MCNG 28752, 4. Distrito Sucre, Río Saguas, at the bridge parking along Paraiso Highway from Biscucuy to Chabasquen (approximately 9°24′N, 70°02′W), collected by A. Flecker et al., 5 Jan 1988, MCNG 18736, 36.

NONTYPE SPECIMENS.—933 specimens (8, 40.7–63.5).

VENEZUELA. Apure: Caño Blanquita, 9.1 km S of La Ceiba, MCNG 11905, 4. Aragua: Río Limon system, tributary 12 km NW of Maracay on highway to Ocumare de la Costa, Parque Nacional Henri Pittier, UMMZ 209405, 6. Río Tuy system, mouth of Cagua, approximately 10 km from Guayas (latter locality at 10°16′N, 67°09′W), MBUCV V-21024, 5. Quebrada La Mesa, NE of Maracay, MBUCV V-3012, 4. Río Pao, near La Candelaria (approximately 10°07′N, 67°14′W), MCNG 14102, 12. Lago de Valencia basin, tributary of Río Castaño, N of Las Delicias, MBUCV V-3036, 13. Parque Nacional Aragua, Rancho Grande, Río Guamitas (approximately 10°21′N, 67°41′W), USNM 132592, 3. Barinas: Caño emptying into Represa Boconó, MCNG 5270, 90. Caño Avaro, MCNG 5333, 1. Río Masparro (approximately 8°04′N, 69°26′W), MCNG 5380, 39. Caño in Estero Chiguira, MCNG 6547, 2. Caño along Río Paguey (8°01′N, 69°38′W), MCNG 7285, 6. Caño 17.5 km NW Río Paguey, MCNG 7333, 7. Caño Grande on Finca Caño Grande, MCNG 7924, 8. Caño Manamo near Coporito, MCNG 10530, 14. Upper Río Caparo, MCNG 10543, 2. Río Las Palmas, USNM 194122, 1. Carabobo: Las Dos Bocas (town on river draining into SE portion of Lago de Valencia, 9°55′N, 67°58′W), MHNLS 1095, 11. Río Agua Caliente, N of El Cambur, MCNG 13980, 3. Río Chirgua, tributary of Río Pao (approximately 9°54′N, 68°09′W), MCNG 15282, 41; MCNG 18050, 170. Río Manuare (approximately 9°49′N, 67°41′W), MCNG 15355, 39. Cojedes: Río Chirgua, MCNG 14264, 14. Distrito Federal: Río Valle, S of Caracas, USNM 121500, 5. Miranda: Río Chuspita, in Chuspita de Lima, along highway from Araira to Salmeron (approximately 10°34′N, 66°19′W), MBUCV V-22531, 5. Río Iscaragua, at Club Iscaragua along highway from Caracas to Guarenas, MBUCV V-24001, 57. Río de Ulua, along border of Río Panaquire, MHNLS 3349, 1. Distrito Sucre, Quebrada Galinda, entrance to Parque Nacional El Avila, MHNLS 9627, 24. Río Tuy basin, Quebrada Ojo de Agua, Baruta (10°26′N, 66°53′W), MHNLS 521, 17; MHNLS 523, 10. San Antonio de Los Altos (10°22′N, 66°56′W), MHNLS 535, 2. Santa Teresa del Tuy, MHNLS 3183, 2. Quebrada Mesia, La Democracia (10°01′N, 66°45′W), MHNLS 2455, 10. Río Tuy basin, Río Las Minas, 7 km E of Santa Teresa del Tuy, MHNLS 524, 11; MHNLS 531, 3. Distrito Sucre, Río Tocome, approximately 200 m from border of Parque Nacional “El Avila” (approximately 10°28′N, 66°49′W), MHNLS 9448, 10. Río Grande, 200 m before the mouth of Río Santa Cruz into Río Grande, Parque Nacional Guatopo, MBUCV V-12519, 6. Río Guare de Tacata, MCNG 14090, 32. Unnamed caño 18 km SW of Tacata (latter locality at 10°12′N, 67°00′W), MCNG 14150, 2. Bridge near Araguita, MCNG 14297, 2. Caño El Lindero, MCNG 17166, 6. Río Mucarao, 8 mi (=12.8 km) W of Caracas, elevation 900 m, AMNH 14268, 13. Río Guiare, near Caracas, USNM 357729, 3 (40.7–62.7; cleared and counterstained for cartilage and bone). Portuguesa: Río Guanare in La Raya, MCNG 120, 8. Río Guanare, near Chabasquen (9°26′N, 69°57′W), MCNG 132, 6. Río Saguaz, along road to Chabasquen, MCNG 134, 5. Río Las Marias, MCNG 3419, 1. Río Tucupido, at dam site, MCNG 5288, 19. Caño emptying into Represa Boconó, MCNG 5399, 3. Pools in Río Boconó MCNG 5451, 28. Río Tucupido in Las Canoas (8°55′N, 69°44′W), MCNG 5649, 13. Río Tucupido at dam site, MCNG 8838, 2. Caño, at bridge km 30 on road from Biscucy, MCNG 9808, 36. Río Guanare, between Guanare and Biscucy, MCNG 10050, 1. Río Las Marias on route to San Juan, MCNG 10910, 3. Río La Estacion, MCNG 11608, 19. Río Moroturo, near Aparicion (approximately 9°24′N, 69°23′W), MCNG 11815, 22. Caño Bombicito, near Aparicion (approximately 9°24′N, 69°23′W), MCNG 11841, 13. Caño La Laja, Río Guarguero, MCNG 12484, 10. Puente Nuevo, 11 km E of Ospino (latter locality at 9°18′N, 69°27′W), MCNG 12748, 2. Caño N of Las Majaguas, Paso Cojedes, MCNG 12806, 2. Yaracuy: Quebrada Grande, Río Cojedas basin, near bridge between Nirgua and Chivacoa, USNM 357783, 4.

The following lot is tentatively identified as Creagrutus taphorni (see under “Remarks,” above): VENEZUELA. Tachira. Quebrada La Lejia Bramoncito, near small village of Lejia, along highway from Rubío to La Petrolera, approximately 3 km from Rubío (latter locality at 7°43′N, 72°22′W), MBUCV V-9395, 20 (5, 51.6–63.5).

Creagrutus beni

Creagrutus atrisignum Myers, 1927:116 [type locality: [Brazil], Goyaz (= Goiás), upper Rio Maranhão (upper Rio Tocantins basin)].—Eigenmann and Myers, 1929:549 [based on Myers, 1927].—Fowler, 1948:83 [literature compilation]; 1975:25 [literature compilation].—Géry, 1977:407, 410 [in key, drawing of paratype].

DIAGNOSIS.—The form of the dark humeral mark in Creagrutus atrisignum consisting of a primary variably horizontally elongate central portion and a distinct, smaller, secondary dorsal component, with the two components joined in some individuals by a narrow band of dark chromatophores is autapomorphic within the assemblage consisting of Creagrutus and Piabina. Creagrutus atrisignum is further distinguished in the clade consisting of Creagrutus and Piabina by the combination of the possession of premaxillary dentition arranged in the three components generalized for most of the species of Creagrutus and Piabina without a pronounced gap between the first and second teeth of the primary series, 2 to 4 maxillary teeth, 4 teeth in each dentary, 9 to 11 median predorsal scales, 5 scale rows between the dorsal-fin origin and the lateral line, 9 or 10 branched anal-fin rays, 2 post-anal scales anterior to the anal-fin origin, the well-developed third infraorbital with its ventral margin contacting the horizontal limb of the preopercle, the lack of a series of dark spots along the midlateral surface of the body, the discrete humeral marks whose two components, although encompassing a vertically elongate area, do not form a vertical bar, and the lack of a discrete patch of dark pigmentation on the anterior portion of the middle of the dorsal fin.

DESCRIPTION.—Morphometric and meristic data for Creagrutus atrisignum in Table 7. Head and body moderately robust (Figure 26). Greatest body depth at, to somewhat anterior of, dorsal-fin origin; typically more anterior in larger specimens. Dorsal profile of head smoothly convex from margin of upper lip to vertical through posterior nostril, straight from that point to tip of supraoccipital spine. Interorbital region smoothly convex transversely. Anterior portion of predorsal region of body continuing profile of posterior portion of head; profile becoming more curved posteriorly but without pronounced change in alignment relative to that of head in most specimens. Predorsal region of body somewhat flattened transversely anteriorly, with median ridge proximate to dorsal-fin origin. Ventral profile of head with variably obvious obtuse angle at anteroventral corner of dentary, nearly flat from angle to isthmus. Prepelvic profile of body convex, more so in many larger specimens.

Head obtusely pointed in lateral view, less so in dorsal view. Upper jaw distinctly longer than, and overhanging, lower jaw. Anteromedial portion of snout fleshy with scattered papillae. Papillae more concentrated on fleshy upper lip, especially along ventral margin of lip and on folds and plicae extending between outer and medial premaxillary teeth. Lower lip very fleshy with numerous papillae distributed over dorsal and anterior surfaces.

Characters A B

Morphometrics

Standard length 46.0 37.2–55.2

1. Snout to anal-fin origin 64.6 61.5–68.0

2. Snout to pelvic-fin insertion 49.1 45.4–49.6

3. Snout to pectoral-fin insertion 23.9 22.9–26.2

4. Snout to dorsal-fin origin 51.1 47.5–51.3

5. Dorsal-fin origin to hypural joint 56.5 52.9–56.9

6. Dorsal-fin origin to anal-fin origin 32.6 29.3–32.8

7. Dorsal-fin origin to pelvic-fin insertion 28.5 25.7–28.9

8. Dorsal-fin origin to pectoral-fin insertion 33.9 31.2–35.0

9. Caudal peduncle depth 12.2 11.2–12.3

10. Pectoral-fin length 20.9 19.1–21 9

11. Pelvic-fin length 16.1 14.8–17.4

12. Dorsal-fin length 22.6 20.6–23.5

13. Anal-fin length 16.4 16.4–19 4

14. Head length 27.0 25.5–28.0

15. Postorbital head length 44.4 44.1–45.8

16. Snout length 28.6 28.4–31.7

17. Bony orbital diameter 32.3 31.4–37.1

18. Interorbital width 30.6 30.4–33.3

Meristics

Lateral line scales 37 36–38

Scale rows between dorsal-fin origin and lateral line 5 5

Scale rows between anal-fin origin and lateral line 3 3

Predorsal median scales 9 9–11

Branched dorsal-fin rays 8 8

Branched anal-fin rays 10 9–10

Branched pelvic-fin rays 6 6

Pectoral-fin rays 12 12–13

Vertebrae 36 35–37

Infraorbital series well developed. Ventral margin of third infraorbital contacting horizontal limb of preopercle. Posterior margins of third through fifth infraorbitals slightly separated from vertical limb of preopercle.

Premaxillary dentition in three series: primary row curved, usually with 6, occasionally 5, tricuspidate teeth without pronounced gap between first and second tooth of series but with medial tooth separated from medial tooth of contralateral series by distinct gap; triangular cluster of 3 teeth distinctly larger than those of primary series; and single tooth of form similar to that of primary series occurring lateral to fourth tooth of primary premaxillary row (when 6 teeth present in primary series) or lateral to gap between third and fourth teeth (when 5 teeth present in primary series). Maxilla with 2 to 4 tricuspidate teeth. Dentary with 4 tricuspidate teeth, anterior and posterior cusps barely apparent on posteriormost tooth; second tooth distinctly larger than first and about twice as high as third; fourth tooth distinctly smaller than third.

Dorsal-fin rays ii,8 in all specimens. Dorsal-fin origin approximately at vertical through pelvic-fin insertion. Profile of distal margin of dorsal fin straight to very slightly concave. Anal-fin rays ii,9–10 or iii,9. Profile of distal margin of anal fin straight to slightly concave. Mature males with hooks typically present on anterior 3 or 4 branched rays, hooks rarely present on fifth branched anal-fin ray. Pectoral-fin rays i,11–12. Tip of pectoral fin extending approximately two-thirds distance to pelvic-fin insertion. Pelvic-fin rays i,6,i in all specimens. Tip of pelvic fin extending to anal-fin origin in smaller specimens, falling short of that point and extending posteriorly only to anus in larger individuals. Mature males with hooks present on all branched pelvic-fin rays.

Gill rakers 7–8 + 11–13.

COLORATION IN ALCOHOL.—Head and body of specimens retaining guanine on scales somewhat silvery. Ground coloration of specimens lacking guanine on scales tan. Dorsal surface of head with scattered, dark, small chromatophores. Large stellate chromatophores overlying membranes of dorsal surface of brain. Dorsal surface of snout and upper lip with field of dense chromatophores; chromatophore field more concentrated anterior to nostrils, but only forming discrete crescent-shaped dark pigment patch in larger specimens. Region anteroventral to nostrils with field of chromatophores, but this pigmentation not continuing around ventral and posterior margins of orbit as in many congeners. Dorsal portions of opercle and infraorbital series with patch of chromatophores forming irregular horizontal stripe behind orbit.

Scales of dorsolateral surface of body in specimens over approximately 35 mm SL with basal patch of dark chromatophores and irregular series of chromatophores along distal margin. Region between chromatophore fields hyaline. Overall pigmentation of scales most prominent immediately ventral of dorsal-fin base, and somewhat less so middorsally. Humeral mark dark at all examined sizes, shape ontogenetically variable, rotund in specimens of approximately 20–30 mm SL, slightly horizontally elongate in some specimens of approximately 35 mm SL, and distinctly horizontally elongate and usually wider along its posterior one-half in larger individuals. Variably present series of dark chromatophores less concentrated than those of main body of humeral mark extending ventrally from main portion of mark in larger individuals. Second patch of concentrated chromatophores situated approximately one scale dorsal of anterior portion of main humeral mark. Secondary patch of humeral pigmentation absent in specimens of 20–30 mm SL, slightly developed in specimens of approximately 35 mm SL, and obvious in larger specimens. Two areas of dark humeral pigmentation ranging from completely separated to joined by a thin vertical band of dark chromatophores. Midlateral body stripe formed by both surface and deep-lying chromatophores. Anterior portion of stripe diffuse, extending anteriorly approximately to under middle of dorsal fin in smaller individuals, nearly to posterior margin of humeral mark in larger specimens. Stripe typically most intense on posterior one-half of body and extending onto basal portions of middle caudal-fin rays.

Dorsal fin with last unbranched and anterior branched rays overlain with dark chromatophores and with distal one-half of following 3 or 4 branched rays with scattered, dark chromatophores. Membranes of pigmented rays with numerous dark chromatophores anteriorly and scattered chromatophores posteriorly. Chromatophores on rays and membranes in combination form a diffuse, but obvious, dark spot. Basal portions of anal-fin rays outlined with small dark chromatophores. Caudal-fin rays outlined with small dark chromatophores, giving fin overall dusky appearance. Dense concentration of chromatophores on basal portions of middle caudal-fin rays forming irregular spot variably continuous with midlateral stripe, spot particularly prominent in smaller individuals. Pectoral and pelvic fins typically hyaline, sometimes with few scattered, dark chromatophores.

ECOLOGY.—Stomach contents of specimens prepared for clearing and counter staining consisted solely of parts of larval insects.

DISTRIBUTION.—Creagrutus atrisignum is apparently limited to the Rio Maranhão basin, a tributary of the upper Rio Tocantins (Figure 22, triangles).

MATERIAL EXAMINED.—130 specimens (30, 37.2–55.2).

BRAZIL. Goiás: Rio Maranhão “into Rio Tocantins,” upper Rio Tocantins basin, CAS 41339, 1 (46.0, holotype of Creagrutus atrisignum, formerly IU 17679). Córrego do Monjolo, tributary of Rio Maranhão, CAS 69260, 7 (6, 45.4–51.2, paratypes of Creagrutus atrisignum, formerly IU 17680, in part; see under “Remarks,” above, concerning identity of other specimen in lot); MCZ 31571, 1 (47.5, paratype of Creagrutus atrisignum). Rio Arial-Velho “into Rio Maranhão” (approximately 15°20′S, 47°58′W), CAS 69241, 1 (37.2). Rio Maranhão, at Aqua Quente, CAS 69504, 1 (42.5). Rio Bom-Jesus “into Rio Maranhão,” CAS 69240, 3 (1, 44.6). Salobro “Brook” (?=Córrego Salobro, 15°13′S, 48°08′W), CAS 69260, 3 (50.5–55.2). Niquelândia, Rio do Peixe, right bank tributary of Rio Maranhão (14°28′S, 48°45′W), MNRJ 12662, 16 (14, 37.8–53.5), USNM 341516, 2 (41.4–49.8). Município de Niquelândia, Ribeirão do Engenho, along road from Niquelândia to Codemin, 29 km S of Codemin (14°25′S, 48°28′W), MCP 15929, 54; USNM 341479, 3 (1 specimen cleared and counterstained for cartilage and bone). Município de Niquelândia, Rio Bacalhau, along road from Niquelândia and Colinas (14°32′S, 48°23′W), MCP 15944, 18. Município de Niquelândia, Córrego Fundo, along road from Niquelândia and Colinas (14°28′S, 48° 18′W), MCP 15960, 20.

Creagrutus beni [Venezuela (Sucre) Yarapa River].—Beebe, 1945:84

Creagrutus hysginus Harold et al., 1994:975, fig.1 [type locality: Venezuela, Estado Sucre, Río Güiria, near La Toma].

DIAGNOSIS.—The combination of the possession of premaxillary dentition arranged in the three components generalized for most of the species of Creagrutus and Piabina without a distinctly larger gap between the first and second teeth of the primary series, 4 or 5 teeth on the maxilla, 6 teeth in the primary series of the premaxilla, 6 dentary teeth, 35 to 38 lateral line scales without a lamellar process over each pore, 9 to 11 predorsal median scales, 5 scale rows between the dorsal-fin origin and the lateral line, 36 or 37 vertebrae, 9 or 10 branched anal-fin rays, 2 post-anal median scales to the anal-fin origin, the distance from the dorsal-fin origin to the pelvic-fin insertion (27.5%–33.1% of SL), the distance from the dorsal-fin origin to the pectoral-fin insertion (32.1%–36.8% of SL), the caudal peduncle depth (10.7%–12.9% of SL), the head length (27.3%–30.8% of SL), the length of the postorbital portion of head (44.1%–52.6% of HL), the snout length (21.1%–28.8% of HL), the moderately developed third infraorbital distinctly separated from the horizontal limb of the preopercle, the lack of a series of dark midlateral spots on the body, the absence of a distinct spot of dark pigmentation on the basal portions of the middle caudal-fin rays, the rotund to slightly vertically elongate humeral mark, and the absence of a discrete patch of dark pigmentation on the middle portion of the anterior dorsal-fin rays distinguishes Creagrutus hysginus within the clade composed of Creagrutus and Piabina.

Characters A B

Morphometrics

Standard length 44.9 30.3–55.6

1. Snout to anal-fin origin 66.4 61.7–67.5

2. Snout to pelvic-fin insertion 50.9 46.9–51.6

3. Snout to pectoral-fin insertion 27.7 26.7–31.9

4. Snout to dorsal-fin origin 51.2 48.1–54.6

5. Dorsal-fin origin to hypural joint 54.3 51.4–56.9

6. Dorsal-fin origin to anal-fin origin 33.2 28.3–33.4

7. Dorsal-fin origin to pelvic-fin insertion 31.1 27.5–33.1

8. Dorsal-fin origin to pectoral-fin insertion 36.0 32.1–36.8

9. Caudal peduncle depth 11.7 10.7–12.9

10. Pectoral-fin length 19.5 18.1–22.5

11. Pelvic-fin length 16.2 15.1–17.0

12. Dorsal-fin length 22.5 19.8–24.5

13. Anal-fin length 19.2 14.8–20.4

14. Head length 29.9 27.3–30.8

15. Postorbital head length 49.0 44.1–52.6

16. Snout length 25.5 21.1–28.8

17. Bony orbital diameter 32.5 28.5–36.1

18. Interorbital width 28.2 25.7–35.0

Meristics

Lateral line scales 37 35–38

Scale rows between dorsal-fin origin and lateral line 5 5

Scale rows between anal-fin origin and lateral line 3 3–4

Predorsal median scales 10 9–11

Branched dorsal-fin rays 8 8

Branched anal-fin rays 10 9–10

Branched pelvic-fin rays 7 7

Pectoral-fin rays 12 11–12

Vertebrae 36 36–37

The brilliant red life coloration of the adipose fin of C. hysginus is not known to occur in any of the few other Creagrutus species for which we have life coloration information. Further life coloration information is necessary to determine whether such adipose-fin pigmentation is unique to, and thus an autapomorphy for, C. hysginus.

DESCRIPTION.—Morphometric and meristic data for Creagrutus hysginus in Table 24. Body slightly rotund abdominally in profile compared with most species in the genus. Maximum body depth approximately one-half of distance between insertions of pectoral and pelvic fins. Anterior profile of snout and dorsal profile of head meeting in rounded obtuse angle near vertical through point midway between nares. Dorsal profile of head posterior to that line inclined and straight to slightly convex. Predorsal profile of body with notable change in alignment relative to that of head, asymmetrically convex, with convexity most pronounced in anterior one-third of region but with some specimens (e.g., holotype, Figure 47) having pronounced curvature immediately posterior to occiput; presence of pronounced curvature not related to sex. Dorsal profile of body straight between dorsal-fin origin and caudal peduncle. Ventral profile of head and body slightly convex from anterior margin of lower jaw to pelvic-fin origin, or with ventral surface of head and abdomen each with distinctly rounded profile. Rounded obtuse angle delimiting anteroventral angle of dentary, angle variably apparent among specimens depending on state of preservation.

Upper jaw longer than, and overhanging, lower jaw. Anterior surface of snout fleshy, with numerous minute papillae over surface; greatest concentration of papillae on upper lip, margin of upper jaw, and in mouth on fleshy flaps and plicae extending between outer and medial premaxillary teeth. Lower lip with thick, fleshy anterior region and numerous papillae on anterodorsal surface.

Infraorbital series moderately well developed, covering approximately two-thirds of cheek. Ventral margin of third infraorbital separated from horizontal limb of preopercle by space equal to approximately one-half width of that infraorbital. Curvature of posteroventral margin of third infraorbital approximately concentric with margin of orbit. Third through fifth infraorbitals distinctly separated posteriorly from vertical limb of preopercle.

Premaxillary dentition in three series: primary series straight, consisting of 6 tricuspidate teeth with rounded to well-developed cusps, without pronounced gap between first and second tooth of series; triangular cluster of 3 larger teeth with medialmost tooth asymmetrical and nearly contacting contralateral tooth of other side; and single tooth similar in form to those of primary premaxillary row, occurring lateral to fourth tooth of primary series. Maxilla with 4 or 5 tricuspidate teeth. Dentary 6 tricuspidate teeth; anterior 3 teeth largest, second tooth about one-third higher than first tooth and nearly twice as high as third tooth; following teeth successively shorter and compressed.

Dorsal-fin rays ii,8. Dorsal-fin origin at vertical through pelvic-fin origin. Profile of distal margin of dorsal fin with slight concavity. Anal-fin rays ii,9–10 or iii,9–10. Profile of distal margin of anal fin nearly straight, with anterior branched rays slightly elongate. Single, bilaterally paired hooks present on 2 or 3 anterior branched anal-fin rays of mature males (hooks observed on only 3 of 20 examined specimens). Mature males with hooks restricted to posterolateral surface of main shaft and posterior, secondary branch of each ray. Pectoral-fin rays i,11–12. Tip of pectoral fin extending posteriorly to pelvic-fin base in mature males as shown by presence of anal- and pelvic-fin hooks; other specimens with pectoral fin extending posteriorly approximately three-fourths of distance between pectoral-and pelvic-fin insertions. Pelvic-fin rays i,7. Tip of pelvic fin approaching or, especially in well-developed mature males, extending to anal-fin origin; with distal portion turned medially in some individuals, giving fin slightly cupped shape. Pelvic-fin hooks in mature males, when present, occurring on all portions of all branched rays, except the smallest, distal branches.

Gill rakers 5–7 + 8–10.

COLORATION IN LIFE.—Adipose fin brilliant red. Less intense orange-red pigmentation present in broad horizontal band through central part of dorsal fin and distal portion of outer caudal-fin rays. Lateral 2 or 3 rays of pelvic and pectoral fins pale orange. Anal fin hyaline. Dorsal surface of eye with bright red patch overlying reflective guanine pigment. Based on the collecting locality, it is likely that the specimens cited as Creagrutus beni by Beebe (1945:84) are C. hysginus. Beebe reported that the species was “Greenish-yellow with silvery sheen, two more or less blue body bands; a very broad oxidized silver lateral band…much of the dorsal, anal and caudal fins is scarlet, as is the iris.” Nocturnal coloring was noted by Beebe as “all body pigment bands and most of the red color disappear at night.”

COLORATION IN ALCOHOL.—Dorsal surface of head with light brown, shallow chromatophores and dark brown to black, deep chromatophores. Deep chromatophores small, punctate, lining interior surfaces of frontal, obscured in midline by connective tissue in fontanel. Shallow chromatophores small to large, stellate, present over entire dorsal surface of head, most concentrated on medial one-half of upper jaw and snout, continuing posterolaterally from snout to nares and posterodorsally to point above center of orbit and overlying fontanel. Small crescent of dark pigmentation often present anterior to nares in other Creagrutus species present and continuous with snout pigmentation. Band of scattered, light and dark chromatophores extending from pigmentation on snout and upper jaw posteriorly across cheek around margin of orbit and almost to distal margin of infraorbital bones, and joining body of scattered chromatophores of various sizes posterior to orbit. Scattered, large, brown, stellate chromatophores arranged in dorsoventrally elongate band on cheek between infraorbitals and preopercle.

Scales of dorsal portion of body with small dark chromatophores concentrated in area medial to scale center and with larger stellate, lighter chromatophores arranged in arc on lateral surface of posterior field. Overall appearance of dorsal pigmentation faintly reticulate, but some specimens having irregularly arranged scales with very darkly pigmented central fields. Small black chromatophores along dorsal midline of body and along margin of dorsal-fin base, forming longitudinal stripe from occiput to caudal peduncle. Humeral mark usually appearing as irregular blotch or rounded mark immediately dorsal to lateral line, but occasionally extending anterodorsally and diffusely, giving overall appearance of inverted comma. Diffuse midlateral stripe present, extending posteriorly from area behind humeral mark onto, and slightly expanding on, caudal-fin base. Deep-lying pigmentation of midlateral stripe mostly obscured by overlying guanine in examined specimens. Stripe most sharply defined ventrally and posteriorly. Region of body between midlateral stripe and anal-fin base with very small, dark chromatophores delineating myosepta. Anal-fin base only diffusely pigmented, without dark triangular pigmentation patches present in some congeners.

Small, dark chromatophores present on caudal-fin membranes; greatest concentration of chromatophores in association with central rays, appearing as disjunct extension of midlateral stripe, and on dorsal and ventral branched rays and procurrent rays. In juveniles (approximately 20–22 mm SL), pigmentation of middle caudal-fin rays concentrated basally and appearing as small spot. Ventral lobe of caudal fin much more densely pigmented overall than dorsal lobe. Small dark chromatophores on distal one-half of anal-fin membranes, some specimens showing great enlargement of these chromatophores, giving appearance of dark spot in central portion of fin. Diffuse dark pigmentation in narrow bands immediately adjacent to anterior surfaces of basal, unsegmented portions of rays and mainly restricted to narrow bands immediately adjacent to all portions of fin rays. Distal portions of unbranched and anterior two branched anal-fin rays unpigmented. Dark chromatophores of various sizes present across dorsal-fin membranes; pigmentation often darkest and densest in posterior one-half of fin in distal one-half of membrane. Pectoral fin hyaline except for single line of small dark chromatophores on basal one-half of lateral, unbranched ray. Pelvic fin hyaline.

ECOLOGY.—Creagrutus hysginus is quite abundant in the Ríos Bautista and Güiria. These are small rivers of crystal-clear water that descend from the mountains of the central Peninsula de Paria, northeastern Venezuela. The substrate of both rivers is coarse, ranging mainly from gravel to large stones with small amounts of sand present. Creagrutus hysginus occurs in fast-flowing current as well as quiescent backwater areas. The surrounding forest contributes large amounts of allochthonous material to the streams, including leaves, flowers and fruit, and terrestrial insects. Examination of gut contents of C. hysginus revealed that the species feeds on this material as well as aquatic dipteran larvae.

Beebe (1945:84) reported that C. hysginus (cited as C. beni; see under “Remarks,” below) was one of the species surviving in the mixture of damp mud and decaying vegetation at the bottom of a drying creek-bed in Río San Juan basin south of Caripito in the state of Monagas, Venezuela.

DISTRIBUTION.—The known distribution of Creagrutus hysginus is restricted to several rivers draining into the Golfo de Paria in the coastal states of Sucre and Monagas, northeastern Venezuela (Figure 43, diamonds). In the Peninsula de Paria, C. hysginus has been collected in the upland portions of the Ríos Bautista, Güiria, Irapa, and Yoco. Creagrutus species were absent in the 20 collections of freshwater fishes from the lowland region near the base of the peninsula as reported by Fernández-Yépez (1969). The species also occurs in upland tributaries of the Río San Juan of Sucre and Monagas states that flows into the western portions of the Golfo de Paria.

MATERIAL EXAMINED.—667 specimens (28, 30.3–55.6).

VENEZUELA. Sucre: Río Güiria, near La Toga, MBUCV V-20310, 1 (44.9, holotype of Creagrutus hysginus); CAS 79623, 9 (33.2–43.0, paratypes of Creagrutus hysginus; 1 specimen cleared and counterstained for cartilage and bone); MBUCV V-24002, 20 (paratypes of Creagrutus hysginus); USNM 326055, 10 (34.1–44.5, paratypes of Creagrutus hysginus; 2 specimens cleared and counterstained for cartilage and bone); MBUCV V-24003, 186. Río Bautista, Sector Río above last Carretera, MBUCV V-20304, 12 (4, 30.3–37.6, paratypes of Creagrutus hysginus; 1 specimen cleared and counterstained for cartilage and bone). Río La Toga, 6 km N of road 9, approximately 4 km W of Güiria, CAS 80270, 10 (paratypes of Creagrutus hysginus); MCNG 19691, 148 (paratypes of Creagrutus hysginus); USNM 326035, 10 (paratypes of Creagrutus hysginus; two specimens cleared and counterstained for cartilage and bone). Río Yarapa (locality uncertain; see comments under “Remarks,” above), ANSP 53383–6, 4 (45.4–55.6; 1 specimen cleared and counterstained for cartilage and bone). Río Güiria, NE of Güiria, MBUCV V-20288, 3. Río Yoco, sector Chaguaramas, NW of Yoco, MBUCV V-20295, 25. Río Irapa, MCNG 16174, 5. Río Güiria, west of Güiria, MCNG 16768, 5. Caño E of Campo Claro, MCNG 16776, 21. Río Yoco, near Güiria, MHNLS 9715, 14. Quebrada El Mango, tributary to Río Capiricual (Río San Juan system), MHNLS 9832, 31. Monagas: Río Cocollar, Río Guarapiche tributary (Río San Juan system), MHNLS 9830, 7. Río Capiricual, tributary to Río Guarapiche (Río San Juan system), S of El Arbolito, MHNLS 9831, 146.

Creagrutus beni. USNM 340959, 2, 36.4–43.0 mm; Bolivia, Cochabamba, Río Chapare basin, Villa Tunari

Creagrutus bolivari, ANSP 159831, 2, 40.7–48.2 mm SL; Venezuela, Bolivar, Río Cariapo basin. NRM 16844, 2, 51.7–54.7 mm; Colombia, Meta, Río Meta basin.

Creagrutus brevipinnis, USNM 120148, 2, 44.7–46.8 mm; Colombia, tributary of upper Río Cauca.

Creagrutus beni és una espècie de peix de la família dels caràcids i de l'ordre dels caraciformes.

Creagrutus beni es una especie de peces de la familia Characidae en el orden de los Characiformes.

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Creagrutus beni Creagrutus generoko animalia da. Arrainen barruko Actinopterygii klasean sailkatzen da, Characidae familian.

本氏鈎齒脂鯉，為輻鰭魚綱脂鯉目脂鯉亞目脂鯉科的其中一個種，分布於南美洲Madeira河上游流域，體長可達7.3公分，棲息在底中層水域，生活習性不明，可作為觀賞魚。