Creagrutus atratus Vari & Harold 2001

Creagrutus atratus

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 in the primary series, typically 6 teeth in primary series of each premaxilla, 3 or 4 maxillary teeth, 5 or 6 teeth on each dentary, 10 to 13 median predorsal scales, 38 to 42 lateral line scales without a lamellar process over each pore, 4, rarely 5, scale rows between the dorsal-fin origin and the lateral line, 3 or 4 scale rows between the anal-fin origin and the lateral line, 9 to 13 branched anal-fin rays, 6 to 8 gill rakers on the upper limb and 8 to 10 gill rakers on the lower limb of the first gill arch, 38 or 39 vertebrae, the postorbital head length (45.5%–52.8% of HL), the bony orbital diameter (24.4%–32.0% of HL), the interorbital width (34.0%–37.9% of HL), the caudal peduncle depth (12.1%–13.6% of SL), the two post-anal median scales to the anal-fin origin, the contact or near contact between the ventral margin of the third infraorbital and the horizontal limb of the preopercle, the lack of a distinct spot of dark pigmentation at the base of the middle caudal-fin rays, the vertically elongate, ventrally tapering humeral mark without a secondary, dorsally situated patch of pigmentation, the absence of a distinct patch of pigmentation on the dorsal fin, and the lack of a series of dark spots along the midlateral surface of the body distinguishes Creagrutus atratus within the clade formed by Creagrutus and Piabina.

DESCRIPTION.—Morphometric and meristic data for Creagrutus atratus in Table 6. Head and body relatively robust, increasingly so in larger specimens. Greatest body depth at dorsal-fin origin in specimens of up to about 35 mm SL, shifted anteriorly approximately to midway between pectoral- and pelvic-fin insertions in larger specimens with more rotund prepelvic profiles. Dorsal profile of head distinctly convex from margin of upper lip to vertical through anterior margin of eye, straight or very slightly convex from that point to tip of supraoccipital spine. Interorbital region distinctly rounded overall transversely, but with some median flattening in larger specimens. Dorsal profile of body nearly straight from tip of supraoccipital spine to dorsal-fin origin in specimens smaller than approximately 35 mm SL, increasingly convex in larger specimens, with distinct change in profile relative to that of the head. Predorsal region of body with obtuse median ridge proximate to dorsal-fin origin. Ventral profile of head with obtuse angle at anteroventral corner of dentary, approximately straight from that angle to isthmus. Prepelvic region of body slightly convex in specimens smaller than 30 mm SL, convexity increasing in larger specimens.

Head obtusely pointed in lateral view and somewhat compressed in dorsal view. Upper jaw longer than, and overhanging, lower jaw. Papillae in some individuals much more broadly distributed than in many congeners. Smaller specimens with papillae scattered ove dorsal portion of head, snout, and upper and lower lips. Larger individuals with papillae field more extensive. Some individuals with papillae on dorsal and lateral surfaces of head, including infraorbitals and opercular series, with papillae also present on upper lip and jaw, on folds and plicae extending between outer and medial premaxillary teeth, and on anterior and lateral surfaces of lower jaw. Occasionally papillae extending onto scales of anterodorsal portions of body. Variation in degree of development of papillae field not correlated with any externally obvious sexual differences. No correlation found between numbers of papillae and body size, with comparable-sized specimens collected at same time and location showing significant differences in the extent of papillae fields. Papillae fields poorly developed in some available population samples, perhaps reflecting seasonality in their presence.

Characters A B

Morphometrics

Standard length 86.4 35.4–91.5

1. Snout to anal-fin origin 60.5 60.2–67.6

2. Snout to pelvic-fin insertion 48.0 47.0–54.0

3. Snout to pectoral-fin insertion 22.6 22.3–27.6

4. Snout to dorsal-fin origin 45.8 44.8–49.5

5. Dorsal-fin origin to hypural joint 57.1 54.3–59.2

6. Dorsal-fin origin to anal-fin origin 31.1 29.6–35.3

7. Dorsal-fin origin to pelvic-fin insertion 27.9 27.4–34.0

8. Dorsal-fm origin to pectoral-fin insertion 33.4 32.3–36.2

9. Caudal peduncle depth 12.2 12.1–13.6

10. Pectoral-fin length 19.6 18.4–21.3

11. Pelvic-fin length 13.7 13.3–16.7

12. Dorsal-fin length 21.2 19.6–23.5

13. Anal-fin length 15.9 15.5–20.9

14. Head length 24.5 25.5–28.1

15. Postorbital head length 50.0 45.5–52.8

16. Snout length 28.3 26.6–31.6

17. Bony orbital diameter 25.9 24.4–32.0

18. Interorbital width 35.4 34.0–37.9

Meristics

Lateral line scales 41 38–42

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

Scale rows between anal-fin origin and lateral line 32 3–42, 3

Predorsal median scales 12 10–13

Branched dorsal-fin rays 8 8

Branched anal-fin rays 12 9–134

Branched pelvic-fin rays 6 5–75

Pectoral-fin rays 12 11–14

Vertebrae 38 38–39

1Five scale rows above lateral line present in only 5 of 49 paratypes.

2Larger specimens with short sheath of small scales along anterior portion of base of anal fin, giving appearance of an additional row of scales.

3Four scale rows below lateral line present in only 4 of 49 paratypes.

4Nine anal-fin rays present in only 3 of paratypes, one of these 3 with distinct gap within anal-fin ray series.

5Five branched rays present in 1 paratype; 7 branched rays present in 1 paratype.

Infraorbital series relatively well developed. Ventral margin of third infraorbital varyingly curved, deepest portion of third infraorbital contacting, or nearly contacting, horizontal limb of preopercle. Posterior margins of third through fifth infraorbitals distinctly separated from vertical limb of preopercle.

Premaxillary dentition in three series: primary series straight to slightly curved, typically with 6 tricuspidate teeth, but with 5 teeth present as variant on one, or rarely both, premaxillae in some specimens, without pronounced gap between first and second tooth of series but with medial tooth separated from contralateral series by distinct gap; triangular cluster of 3 tricuspidate teeth, all somewhat to distinctly larger than those of primary tooth row; and single tooth comparable in form and size to those of primary series occurring lateral to fourth tooth of primary premaxillary row (when 6 teeth present in primary row) or in area of contact of third and fourth teeth (when 5 teeth present in primary row); second tooth lateral to primary premaxillary row present on one side of head in one specimen. Maxilla with 3 tricuspidate teeth in smaller individuals, with 3 or 4 teeth in larger specimens. Dentary with 5 or 6 teeth. Three anterior dentary teeth distinctly larger and tricuspidate with central cusp largest. Second tooth slightly longer vertically than first tooth and about twice as high as third tooth. Fourth and fifth or sixth teeth slightly tricuspidate and graduated in size.

Dorsal-fin rays typically ii,8; iii,8 in one specimen. Dorsal-fin origin slightly anterior to vertical through pelvic-fin insertion. Profile of distal margin of dorsal fin straight to slightly concave, concavity typically more pronounced in larger individuals. Anal-fin rays ii,9–13 or iii,11–13. Profile of distal margin of anal fin concave, with slight anterior lobe developed in some specimens. Anal-fin hooks present in mature males of many congeners not present in any of examined specimens of present species. Pectoral-fin rays i,10–13. Tip of pectoral fin reaching posteriorly approximately two-thirds of distance to pelvic-fin insertion. Pelvic-fin rays i,5–7, typically i,6. Tip of pelvic fin reaching posteriorly to anal-fin insertion in some smaller individuals, falling 2 or 3 scales short of that point in larger specimens. Pelvic-fin hooks present in mature males of many congeners not present in any of examined specimens.

Body scales sometimes with papillae (see above); scales extending onto basal region of central portions of each caudal lobe.

Gill rakers 6–8 + 8–10. Some larger individuals have gill rakers on lower portion of first gill arch forked distally.

COLORATION IN ALCOHOL.—Overall dark pigmentation highly variable between samples and within certain lots. Ground coloration tan. Small specimens with light overall head and body coloration having dense field of dark chromatophores overlying brain and less concentrated chromatophore field over anterodorsal portion of head. Other small individuals with more intense overall pigmentation with nearly solid dark pigmentation field on dorsal surface of head. Larger specimens with continuous chromatophore field on dorsal surface of head, but with overall darkness function of intensity of individual chromatophores. Lighter specimens showing crescent-shaped darker chromatophore field anterior to nostril and posteroventrally angled band of dark chromatophores extending from under nostrils to below anteroventral portion of orbit. Both of these pigmentation patterns subsumed into darker head pigmentation in individuals with overall darker coloration. Dispersed dark chromatophores on dorsal portions of first and second infraorbitals, dorsal portion of third infraorbitals, and over fourth and fifth infraorbitals; chromatophore field extending more ventrally on first to third infraorbitals in larger specimens. Region of cheek between posterior margin of third infraorbital and vertical limb of preopercle with vertically elongate chromatophore field continuous dorsally with dark pigmentation situated posterior of orbit. Opercle pigmented other than along its posteroventral one-third in some specimens; pigmentation forming variably shaped, vertically elongate dark mark; spot more extensive in individuals with overall darker pigmentation.

Scales of dorsolateral portion of body with dark chromatophores concentrated along margin of scales and forming reticulate pattern. Humeral mark vertically elongate and ventrally tapering. Mark extending from about one scale ventral of lateral line to one and one-half scales from dorsal midline. Humeral mark distinct in lightly colored specimens, especially smaller individuals, somewhat less distinct, albeit still obvious, in most darker specimens, and nearly completely subsumed into overall body pigmentation in very dark individuals. Broad midlateral stripe extending from posterior margin of humeral mark to rear of caudal peduncle. Pigmentation of stripe consisting both of band of deep-lying, diffuse, dark coloration and of discrete, dark chromatophores overlying scales.

Distal one-fourth to two-thirds of dorsal-fin rays with small dark chromatophores outlining rays and ray segments; scattered chromatophores over intervening membranes, usually not extending as far basally as pigmentation located along ray margins. Specimens with particularly dark overall pigmentation having dusky region extending across middle portion of dorsal fin. Caudal-fin rays outlined by chromatophores, giving fin dusky appearance; pigmentation more intense in overall darker specimens, with middle caudal-fin rays darker than remainder of fin, albeit not forming discrete stripe; ventral lobe of caudal fin usually more intensely pigmented than dorsal lobe, but with difference less obvious in very dark specimens. Anal fin ranging from hyaline to having distal one-half to two-thirds of rays outlined by small dark chromatophores with scattered chromatophores on intervening membranes. Individuals with particularly dark overall pigmentation with region of dusky pigmentation extending along middle section of anterior half of fin. Pelvic fin ranging from hyaline to having rays outlined by small, dark chromatophores. Pectoral-fin rays outlined by chromatophores, more so in darker individuals.

ETYMOLOGY.—The specific name, atratus, from the Latin for dressed in black, refers to the dark coloration of the type series and many of the available specimens.

ECOLOGY.—Creagrutus atratus occurs with C. bolivari at least in two localities, as shown by some examined lots.

DISTRIBUTION.—Creagrutus atratus occurs in the western portions of the Río Orinoco basin in the foothills of the eastern Cordillera of the Andes (Figure 22, stars).

MATERIAL EXAMINED.—97 specimens (55, 35.4–91.5).

HOLOTYPE.—COLOMBIA. Cundinamarca: Río Meta basin, Río Caqueza, tributary to Río Negro, about 2 km upstream of village of Caqueza (latter at 4°25′N, 73°57′W), collected by A.M.C. Silfvergrip, 5 Dec 1987, ICNMHN 4158, 1 (86.4).

PARATYPES.—49 specimens (49, 35.4–91.5).

COLOMBIA. Cundinamarca: Río Meta basin, Río Caqueza, tributary to Río Negro, about 2 km upstream of village of Caqueza (latter at 4°25′N, 73°57′W), collected with holotype, NRM 16842, 19 (48.5–89.3); USNM 353866, 5 (51.3–80.8). Río Meta basin, backwater of Río Negro, at Caqueza (4°27′N, 73°53′W), collected by J.E. Böhlke et al., 4 Apr 1975, ANSP 134080, 5 (49.3–69.6). Río Meta basin, Río Sanane, where emptying into Río Negro (approximately 4°20′N, 73°52′W), collected by A.M.C. Silfvergrip, 19 Dec 1987, NRM 16843, 15 (35.4–91.5); USNM 353867, 5 (47.5–67.7; 2 specimens cleared and counterstained).

NONTYPE SPECIMENS.—47 specimens (5, 46.3–70.1).

COLOMBIA. Cundinamarca: Río Meta basin, mouth of the Río Caqueza, where emptying into Rio Negro, NRM 16841, 32; USNM 353865, 5 (46.3–70.1). Meta: Río Meta basin, Río Guayuriba, where crossed by road between Villavicencio and Acacias, NRM 16852, 2; NRM 16851, 5. Río Meta basin, Río Guayuriba, approximately 4 km south of village of Santa Rosa, NRM 16850, 3.

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

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

(RLQ=window.RLQ||[]).push(function(){mw.log.warn("Gadget "ErrefAurrebista" was not loaded. Please migrate it to use ResourceLoader. See u003Chttps://eu.wikipedia.org/wiki/Berezi:Gadgetaku003E.");});

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

黑體鈎齒脂鯉，為輻鰭魚綱脂鯉目脂鯉亞目脂鯉科的其中一個種，分布於南美洲奧里諾科河西部流域，體長可達7公分，棲息在底中層水域，生活習性不明。