Comprehensive Description
provided by Smithsonian Contributions to Zoology
Creagrutus ouranonastes
DIAGNOSIS.—The possession of premaxillary dentition with the three components generalized for the species of Creagrutus, but with a distinct gap between the first and second teeth of primary tooth row and a forward position of the triangular cluster of three posteromedial teeth distinguishes C. ouranonastes from all members of the clade formed by Creagrutus and Piabina with the exception of Creagrutus maracaiboensis, C. melanzonus, C. muelleri, C. nigrostigmatus, C. peruanus, C. runa, and Piabina argentea. Creagrutus ouranonastes can be distinguished from these seven species by the combination of 7 dentary teeth, 41 to 45 lateral line scales, 13 to 15 predorsal median scales, 6 scale rows between the dorsal-fin origin and the lateral line, 4 scale rows between the anal-fin origin and the lateral line, 40 to 43 vertebrae, 10 or 11 branched anal-fin rays, the distance from the snout to the anal-fin origin (62.7%–65.6% of SL), the caudal peduncle depth (12.4%–14.1% of SL), the bony orbital diameter (25.7%–29.4% of HL), and the possession of two small, discrete spots of dark pigmentation on the basal portions of the middle caudal-fin rays, a pigmentation pattern that is an autapomorphy for the species.
DESCRIPTION.—Morphometric and meristic data for Creagrutus ouranonastes in Table 42. Head and body quite robust, increasingly so in larger specimens. Greatest body depth at vertical through dorsal-fin origin in smaller specimens, shifting distinctly anterior of that point in larger, more robust individuals (e.g., holotype, Figure 72). Dorsal profile of head distinctly convex from margin of upper lip to vertical through posterior margin of posterior nares, nearly straight from that point to rear of head in specimens of all sizes. Dorsal profile of body smoothly continuous with profile of head in smaller individuals, more convex with distinct change in slope relative to alignment of dorsal profile of head in larger specimens; nearly straight from dorsal-fin origin to caudal peduncle in specimens of all sizes. Ventral profile of head somewhat more convex at anteroventral corner of dentary or somewhat posterior of that point, nearly straight from convex region to rear of isthmus. Ventral profile of body gently convex in smaller individuals, convexity more pronounced in larger specimens.
Characters A B
Morphometrics
Standard length 100.1 38.2–91.2
1. Snout to anal-fin origin 62.4 62.7–65.6
2. Snout to pelvic-fin insertion 46.2 45.4–49.6
3. Snout to pectoral-fin insertion 22.2 21.5–25.3
4. Snout to dorsal-fin origin 48.7 46.4–51.4
5. Dorsal-fin origin to hypural joint 56.0 52.1–57.9
6. Dorsal-fin origin to anal-fin origin 31.7 27.4–32.3
7. Dorsal-fin origin to pelvic-fin insertion 28.2 25.6–30.0
8. Dorsal-fin origin to pectoral-fin insertion 36.0 33.3–37.2
9. Caudal peduncle depth 13.4 12.4–14.1
10. Pectoral-fin length 20.5 20.0–21.0
11. Pelvic-fin length 15.3 14.9–16.7
12. Dorsal-fin length 21.3 20.6–23.6
13. Anal-fin length 18.6 15.7–18.7
14. Head length 23.8 22.7–25.9
15. Postorbital head length 52.1 46.7–54.5
16. Snout length 28.2 24.0–29.0
17. Bony orbital diameter 27.3 25.7–29.4
18. Interorbital width 34.8 30.0–35.7
Meristics
Lateral line scales 45 41–45
Scale rows between dorsal-fin origin and lateral line 6 6
Scale rows between anal-fin origin and lateral line 4 4
Predorsal median scales 14 13–15
Branched dorsal-fin rays 8 8
Branched anal-fin rays 10 10–11
Branched pelvic-fin rays 7 6–7
Pectoral-fin rays 12 13–14
Vertebrae 42 40–43
Head obtusely pointed in both lateral and dorsal views. Upper jaw slightly longer than, and overhanging, lower jaw. Anterior of snout only slightly fleshy compared to many congeners, with papillae only obvious along anteromedial portion of snout, along margin of upper lip and on folds and plicae extending between outer and medial premaxillary teeth. Lower lip relatively fleshy anteriorly, with numerous papillae on dorsal surface of lip.
Infraorbital series moderately developed, without notable variation in degree of development across available body size range. Ventral margin of third infraorbital falling distinctly short of horizontal limb of preopercle. Posterior margins of third through fifth infraorbitals falling distinctly short of vertical limb of preopercle.
Premaxillary dentition in three series: primary row curved, consisting of 6, rarely 5, teeth, with distinct gap between first and second tooth in row, and between medial teeth of contralateral series; triangular cluster of three teeth with anterior tooth approximately same size as teeth of primary row and slightly medial to pronounced gap between first and second teeth of primary row, two other teeth of triangular cluster, particularly posteromedial tooth larger than remaining teeth in jaw; and single tooth of form similar to that of primary series lying lateral to fourth tooth of primary premaxillary tooth row. Maxilla with 3 or 4 tricuspidate teeth. Dentary with 7 teeth; first and second teeth distinctly larger than others, subequal and tricuspidate; third tooth tricuspidate, about two-thirds height of second tooth; fourth through seventh teeth unicuspidate, distinctly smaller than third tooth, and gradually decreasing in size posteriorly.
Dorsal-fin rays ii,8. Dorsal-fin origin slightly behind vertical though pelvic-fin insertion. Profile of distal margin of dorsal fin slightly concave. Anal-fin rays ii,10–11. Profile of distal margin of anal fin distinctively concave. Hooks typically present on anal-fin rays in mature males of many Creagrutus species not present in examined specimens. Pectoral-fin rays i,11–13. Tip of pectoral fin extending posteriorly slightly more than three-fourths of distance to vertical through pelvic-fin insertion. Pelvic-fin rays i,6,i in smaller examined specimens, i,7 in larger individuals. Hooks typically present on pelvic-fin rays in mature males of many Creagrutus species not found in examined specimens. Tip of pelvic fin falling distinctly short of anal-fin origin.
Gill rakers 7–8 + 10–11.
COLORATION IN ALCOHOL.—Overall coloration of head and body relatively dark other than in specimens less than 30 mm SL. Dorsal surface of head with dense field of small, dark, stellate chromatophores. Chromatophore field extending over snout, upper lip, and continuing posteriorly under and posterior to orbit. No intense patch of crescent-shaped pigmentation anterior to nares as present in many other Creagrutus species. Pigmentation ventral and posterior of orbit not forming discrete band present in many congeners. Pigmented regions on head becoming progressively more intense in larger specimens. Pigmentation on infraorbitals posterior of orbit concentrated into dark irregular spots in some individuals. Deep-lying patch of dark pigmentation located medial to posterior portion of fifth infraorbital and central portion of opercle; pigmentation in latter region more intense in larger specimens and forming distinct patch of dark coloration on opercle.
Dorsolateral surface of body with scale margins marked by bands of dark pigmentation forming overall reticulate pattern. Humeral mark vertically elongate, overall form that of inverted comma; particularly dark portion of humeral mark located immediately dorsal of lateral line, and less intensely pigmented curved portion of mark extending anterodorsally from that region for distance of about two scales. Midlateral dark pigmentation on body composed of two components: deep-lying band of chromatophores extending somewhat obliquely from behind humeral mark to center of caudal peduncle and narrower, irregular band of darker surface pigmentation.
Dorsal fin with small dark chromatophores on rays and membranes, particularly on anterior rays and distal portions of middle dorsal-fin rays. Anal fin with scattered, dark chromatophores on rays and membranes. Caudal fin with dark chromatophores outlining rays. Basal portion of middle rays of caudal fin flanked by two discrete, horizontally elongate patches of particularly dark pigmentation. Pectoral and pelvic fins with scattered, dark chromatophores on membranes.
ETYMOLOGY.—The specific name, ouranonastes, from the Greek, ouranos, heaven or sky, and nastes, inhabitant, refers to the relatively high elevation localities where the species has been collected.
ECOLOGY.—Nothing is known about the life history of Creagrutus ouranonastes, but it is found at a notable elevation for a Creagrutus species. Some of the localities at which specimens were collected are at approximately 1900 m altitude, the greatest elevation recorded for any member of the genus.
Stomach contents of the single specimen prepared for clearing and counter staining consisted of parts of larval insects.
DISTRIBUTION.—Creagrutus ouranonastes is known only from the uplands of the Río Apurimac basin in the southern highlands of Peru (Figure 67, open star) where it is the only member of the genus collected to date.
MATERIAL EXAMINED.—25 specimens (25, 38.2–100.1).
HOLOTYPE.—PERU. Apurimac: Provincia Aymaraes, Río Chalhuanca (approximately 14°01′S, 73°11′W), collected by E. Estacio, 25 Dec 1989, MUSM 8872, 1 (100.1)
PARATYPES.—24 specimens (24, 38.2–91.2).
PERU. Apurimac: Provincia Aymaraes, Río Chalhuanca (approximately 14°01′S, 73°11′W), collected with holotype, USNM 340989, 1 (91.2). Provincia Abancay, Hacienda Matara, Quebrada Matara, Río Matara system (mouth of river at 13°44′S, 72°55′W), 6200 ft (=1890 m) elevation, collected by C. Sanborn, Dec 1941, FMNH 41801, 14 (38.2–86.1). Cusco: Provincia Anta, Río Apurimac, Conocc (13°33′S, 72°37′W), collected by E. Estacio, 9 Nov 1992, MUSM 6574, 5 (41.8–82.0); USNM 340988, 4 (57.2–84.6; 1 specimen cleared and counterstained for cartilage and bone).
Creagrutus paraguayensis Mahnert and Géry, 1988
Creagrutus paraguayensis Mahnert and Géry, 1988:5, figs. 4, 5, pl. 3 [type locality: Río Azotey à Cororo près de l'embouche du Río Ypane, prov. Concepcion, Paraguay (=Paraguay, Concepcion Province, Río Azotey at Cororo, near mouth of Río Ypane)].
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 or 3 teeth on the maxilla, 6, less commonly 5, teeth in the primary tooth row of the premaxilla, 5 or 6 dentary teeth, 37 to 41 lateral line scales without a lamellar process over each pore, 11 to 13 predorsal median scales, 5 scale rows between the dorsal-fin origin and the lateral line, 37 to 39 vertebrae, 13 to 15 branched anal-fin rays, 2 post-anal median scales to the anal-fin origin, the distance from the snout to the anal-fin origin (55.3%–61.0% of SL), the distance from the snout to the dorsal-fin origin (47.2%–51.8% of SL), the distance from the dorsal-fin origin to the anal-fin origin (28.2%–33.8% of SL), the distance from the dorsal-fin origin to the hypural joint (52.5%–57.8% of SL), the distance from the dorsal-fin origin to the pectoral-fin insertion (32.8%–38.3% of SL), the anal-fin length (17.6%–20.7% of SL), the interorbital width (32.0%–38.8% of HL), the lack of a series of dark midlateral spots on the body, the moderately developed third infraorbital with its ventral margin falling distinctly short of the horizontal limb of the preopercle, the 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 paraguayensis within the clade composed of Creagrutus and Piabina.
Characters A B
Morphometrics
Standard length 32.9 30.1–57.5
1. Snout to anal-fin origin 58.7 55.3–61.0
2. Snout to pelvic-fin insertion 43.5 42.6–46.8
3. Snout to pectoral-fin insertion 23.7 22.8–25.1
4. Snout to dorsal-fin origin 49.0 47.2–51.8
5. Dorsal-fin origin to hypural joint 53.8 52.5–57.8
6. Dorsal-fin origin to anal-fin origin 28.7 28.2–33.8
7. Dorsal-fin origin to pelvic-fin insertion 26.5 26.4–31.7
8. Dorsal-fin origin to pectoral-fin insertion 33.4 32.8–38.3
9. Caudal peduncle depth 12.2 10.5–12.5
10. Pectoral-fin length 20.7 19.5–22.3
11. Pelvic-fin length 15.2 15.0–17.7
12. Dorsal-fin length 24.0 21.9–24.8
13. Anal-fin length 20.4 17.6–20.7
14. Head length 24.6 23.0–26.7
15. Postorbital head length 45.2 37.3–45.7
16. Snout length 30.0 26.3–30.1
17. Bony orbital diameter 35.8 31.5–37.6
18. Interorbital width 34.6 32.0–38.8
Meristics
Lateral line scales 38 37–41
Scale rows between dorsal-fin origin and lateral line 5 5
Scale rows between anal-fin origin and lateral line 4 3–4
Predorsal median scales 13 11–13
Branched dorsal-fin rays 8 8
Branched anal-fin rays 15 13–15
Branched pelvic-fin rays 6 6–7
Pectoral-fin rays 12 11–13
Vertebrae 39 37–39
DESCRIPTION.—Morphometric and meristic data for Creagrutus paraguayensis in Table 43. Overall form of head and body moderately elongate in smaller individuals up to approximately 35 mm SL, becoming relatively deeper ontogenetically, with larger examined individuals having proportionately deeper bodies than majority of congeners. Greatest body depth at dorsal-fin origin in smaller individuals and at, or slightly anterior to, that point in larger specimens. Dorsal profile of head distinctly convex anteriorly from margin of upper lip posteriorly to approximately vertical through anterior margin of anterior nares; straight to slightly convex from that point to rear of supraoccipital spine. Predorsal profile of body slightly convex and smoothly continuous with that of head in smaller specimens, somewhat more convex, with associated change in alignment of dorsal profile of body relative to that of rear of head in larger individuals. Dorsal profile of portion of body posterior of dorsal fin relatively straight at all sizes. Ventral profile of head with distinct change in angle at anteroventral corner of dentary; nearly straight from that point to isthmus. Ventral profile of body gently curved, convexity more pronounced in larger specimens. Prepelvic region of body somewhat flattened transversely, with obtuse lateral angles.
Head obtusely pointed in both lateral and dorsal views. Upper jaw longer than, and overhanging, lower jaw. Anterior portion of snout somewhat fleshy, albeit less so than in some congeners. Scattered papillae over anterior portion of snout and upper jaw; papillae more concentrated along margin of upper and lower jaws. Lower lip fleshy anteriorly, with scattered papillae on dorsal surface.
Infraorbital series only moderately developed. Third infraorbital with rounded margin, its ventral margin falling distinctly short of horizontal limb of preopercle. Posterior margins of third to fifth infraorbitals falling distinctly short of vertical limb of preopercle at all body sizes.
Premaxillary dentition in three series: primary row of 6, less commonly 5, teeth arranged in slightly curved row without pronounced gap between first and second tooth of series; single tooth of form similar to that of primary series lying lateral to fourth tooth of primary premaxillary series; and triangular cluster of 3 teeth, larger than those of the primary row and with median tooth of cluster contacting its contralateral partner. Maxilla with 2 or 3 tricuspidate teeth. Dentary with 5 or 6 teeth; first and second teeth tricuspidate, distinctly larger than other teeth, with second tooth larger than first tooth; third tooth approximately one-third height of second tooth. Fourth through sixth teeth distinctly smaller than anterior teeth with fourth and sometimes fifth teeth tricuspidate and sixth and sometimes fifth teeth conical.
Dorsal-fin rays ii,8. Dorsal-fin origin slightly posterior of vertical through pelvic-fin insertion. Profile of distal margin of dorsal fin straight. Anal-fin rays iii,13–15. Profile of distal margin of anal fin distinctly concave. Anal fin in mature males with bony hooks on anterior 5 or 6 branched anal-fin rays; hooks restricted to posterolateral surface of main shaft of ray. Pectoral-fin rays i,10–12. Tip of pectoral fin extending posteriorly to point somewhat short of vertical through pelvic-fin insertion. Pelvic-fin rays typically i,6,i, occasionally i,7. Pelvic fin in mature males with hooks on second through fourth, or more rarely fifth, branched rays. Tip of pelvic fin extending posteriorly to, or slightly beyond, anal-fin origin.
Gill rakers 5–7 + 9–10.
COLORATION IN LIFE.—Field notes associated with some of the nontype specimens (UMMZ 206477) indicate that in life Creagrutus paraguayensis has pale orange fins with a white leading edge to the anal fin. A photo of the live specimen (Axelrod, 1993:111) shows that the species (identified therein as C. beni) has a reddish region above the iris, a pinkish cast to the anal and dorsal fin, and a white stripe along the distal two-thirds of the last unbranched anal-fin ray and distal portion of the following membrane. Guanine mostly masks the dark midlateral body pigmentation and to a degree masks the humeral mark.
COLORATION IN ALCOHOL.—Overall coloration yellowish to tan, without any prominent dark pigmentation pattern on head or body. Dorsal surface of head with scattered, small, dark chromatophores. Chromatophore field somewhat more concentrated anterior to nares, but not forming prominent dark crescent-shaped mark as in many congeners. Faint, but discrete, narrow band of dark chromatophores extending posteriorly from region anterior to nares along ventral and posterior margins of orbit. Fourth and fifth infraorbitals and dorsal portion of opercle with scattered, dark chromatophores. Dorsal and dorsolateral surface of body with field of scattered, dark chromatophores. Chromatophores slightly more concentrated along margins of scales in this area, giving hint of dark reticulate pattern, as pattern not readily visible. Humeral mark mostly located dorsal of lateral line, formed by somewhat larger dark chromatophores that those of surrounding areas of body. Overall form of humeral mark vertically elongate; humeral mark expanding dorsally and merging in that region into slightly darker pigmentation of dorsolateral portion of body.
Dorsal, caudal, and anal fins with scattered, dark chromatophores over rays and membranes; chromatophores typically more concentrated along fin-ray margins in larger specimens. Pectoral and pelvic fins hyaline.
ECOLOGY.—Some of the nontype specimens of Creagrutus paraguayensis (UMMZ 206266, UMMZ 206277, UMMZ 206385) were collected in 8 to 15 m wide streams of up to 2 m depth. The water in two of localities was reported to be “fairly clear” and that of the third site was red-brown during the flood season. The substrate consisted mostly of sand and mud.
DISTRIBUTION.—Creagrutus paraguayensis is known primarily from tributaries of the Río Paraguay in central and northern Paraguay. One lot (NRM 22490) is cited as originating in the headwaters of one unnamed right bank tributary to the Río Paraná (Figure 74, squares). We are, however, unable to confirm that the stream in question actually drains into the Río Paraná because it occurs in a region where the headwaters of rivers draining to Río Paraguay and Río Paraná interdigitate.
COMPARISONS.—Only one Creagrutus species, C. meridionalis, in addition to Creagrutus paraguayensis, is known to occur in the Río Paraguay basin. The two species differ in the number of branched anal-fin rays (13 to 15 in C. paraguayensis versus 11 to 13 in C. meridionalis) and in the number of scales rows between the lateral line and the dorsal-fin origin (5 versus 4, respectively).
DISTRIBUTION.—Creagrutus pearsoni is limited to various rivers in northeastern Bolivia and southeastern Peru that lie within the Rio Madeira basin (Figure 74, dots).
MATERIAL EXAMINED.—101 specimens (26, 22.4–36.1).
BOLIVIA. Cochabamba: Río Popoi (=Popoy) (approximately 15°37′S, 67°18′W), upper Río Beni basin, CAS 62272, 1 (30.7, lectotype of Piabina beni and Creagrutus pearsoni; formerly IU 19317, in part); CAS 87389, 6 (5, 24.9–34.0, paralectotypes of Piabina beni; formerly IU 19317, in part); UMMZ 66495, 3 (28.2–34.0, paralectotypes of Piabina beni; formerly IU 19317, in part). Río Chapare, Todos Santos (16°49′S, 65°08′W), ANSP 84161, 55. Boca Chapare, at mouth of Río Chapare (15°56′S, 64°41′W), ANSP 84164, 9. Río Isiboro, Laguna Motacusal (15°40′S, 65°00′W), USNM 278594, 1 (24.6). Santa Cruz: Río Jorge, 12 km W of Warnes, Río Piray basin (17°31′S, 63°15′W), UF 82332, 2. El Beni: Estacion Biologica Beni, Río Trapiche, USNM 302288, 2 (26.3–30.1); USNM 302274, 2 (29.0–29.1). Mojos, unnamed arroyo 1 km S of Oro momo, Territori Indígena Parque Nacional Isiboro-Sécure (approximately 15°10′S, 65°00′W), CBF 1008, 10 (22.4–36.1). Pando: Provincia Madre de Dios, San Miguel, Río Madre de Dios basin, unnamed arroyo, CBF 848, 4.
PERU. Madre de Dios: Reserva Natural de Tambopata, Río Tambopata system, stream near Laguna Chica (12°50′30″S, 69°17′30″W), USNM 263951, 5 (2, 26.4–30.1; 2 specimens cleared and counterstained for cartilage and bone). Right bank tributary to Río Tambopata, approximately 200 m above mouth of Río La Torre (12°50′S, 69°18′W), USNM 263953, 1.
- bibliographic citation
- Vari, Richard P. 2001. "Phylogenetic study of the neotropical fish genera Creagrutus Günther and Piabina Reinhardt (Teleostei:Ostariophysi:Characiformes), with a revision of the cis-Andean species." Smithsonian Contributions to Zoology. 1-239. https://doi.org/10.5479/si.00810282.613
