Geophagus winemilleri , López-Fernández, Hernán & Taphorn, Donald C., 2004
treatment provided by
Geophagus winemilleri n. sp.
( Figs. 2View FIGURE 2 c, 10–13)
Holotype. MCNGAbout MCNG 35486, 195.0 mm SL; Venezuela: Amazonas: Río Siapa: Laguna Yocuta, (2.1347 N 66.3742 W); K. Winemiller and D. Jepsen, 21 Jan 1997.
Paratypes. MCNGAbout MCNG 12227, 9, 24.5–47.3 mm SL (4 measured); Venezuela: Amazonas: Río Casiquiare: El Porvenir, approx. 60 Km. from confluence with Río Negro (2.0833 N 66.5 W); L. Nico, E. Conde, P. Cardozo, G. Aymard and B. Stergios, 15 April 1985. — AMNHAbout AMNH 233637 (exMCNG 12301), 1, 188.0 mm SL; Venezuela: Amazonas: Caño Emoni, 2 Km. upstream from confluence with Río Siapa (2.1167°N 66.3333°W); L. Nico, E. Conde, P. Cardozo, G. Aymard and B. Stergios, 17 April 1985. — MCNGAbout MCNG 37858, 29, 19.2–149.0 mm SL (5 measured); Venezuela: Amazonas: Río Casiquiare: Isla Cuamate, past Solano (2.0083°N 66.8994°W); L. Nico, S. Walsh, A. Arrington and A. Añez, 0 7 Jan 1998. — AMNHAbout AMNH 233638 (exMCNG 42016), 13, 18.0–113.6 mm SL (2 measured); Venezuela: Amazonas: Río Negro: Punta de Barbosa community (1.9844°N 67.1183°W); L. Nico, H. Jelks and H. LópezFernández, 0 6 Jan 1999. — MCNGAbout MCNG 42386, 2, 97.9–118.3 mm SL; Venezuela: Amazonas: Río Negro: Mavajaté rapids (1.9872°N 67.1233°W); L. Nico, H. Jelks, A. Barbarino, K. Winemiller, H. LópezFernández, F. Pezold, 18 Jan 1999.
Diagnosis. A preopercular mark distinguishes Geophagus winemilleri from G. grammepareius , G. taeniopareius , G. argyrostictus and G. harreri , which have a complete infraorbital stripe, and from G. abalios n. sp., G. brokopondo , G. surinamensis , G. megasema , G. camopiensis , and G. altifrons , which lack head markings. Preserved specimens of G. winemilleri can be distinguished from other species with preopercular mark by the possession of 4 ventrallyinclined, parallel lateral bars, as opposite to G. dicrozoster n. sp. (7 bars) and G. brachybranchus and G. proximus (no bars) ( Fig. 2View FIGURE 2).
Description. Based on holotype (195.0 mm SL) with notes on variation in 14 paratypes 41.8 to 188.0 mm SL. Measurements and counts are summarized in Table 1. Sexes appear to be isomorphic.
Shape. Moderately elongate; dorsal outline more convex than ventral outline; head broader ventrally than dorsally; specimens 45.0 mm SL and smaller with rounder nape; interorbital area moderately concave. Dorsal head profile slightly curved above upper lip, then straight, steeply ascending to orbit, slightly convex or straight (specimens smaller than 118.0 mm SL) in front of orbit, then sloping to dorsalfin origin; descending, slightly convex to last ray of dorsal fin, then straight, almost horizontal to caudalfin base. Ventral head profile straight, slightly descending; chest moderately convex; straight, horizontal from pelvicfin insertion to origin of anal fin; analfin base straight, slightly ascending; ventral caudal peduncle straight, slightly ascending; caudal peduncle about 1.5 times longer ventrally than dorsally. Lips moderately wide, lower with slightly caudally expanded fold (see Kullander et al., 1992, Fig. 3View FIGURE 3). Maxilla not quite reaching middle vertical line between nostril and orbit; ascending premaxillary process reaching lower half of orbit. Opercule, preopercule, cleithrum, postcleithrum, and posttemporal lacking serration.
Scales. E 1 32 (1), 34 (5), 35 (9); scales between upper lateral line and dorsal fin 6.5–7.5 anteriorly, 2.5 posteriorly. Scales between lateral lines 2. Scales on upper lateral line 21 (1), 22 (4), 23 (5), 24 (3), 25 (2) and lower lateral line 13 (1), 14 (5), 15 (5), 16 (2). Anterior 1 / 3 to 1 / 2 of cheek naked, remainder with ctenoid scales; cheek scale rows 7–8. Opercule and subopercule covered with ctenoid scales; interopercule naked except caudodorsal region with ctenoid scales. Single postorbital column of mostly ctenoid scales. Occipital and flank scales ctenoid. Circumpeduncular scale rows 7 above upper, 9 below lower lateral lines, ctenoid.
Fin scales. Anal, pectoral and pelvic fins naked. Dorsal fin scaled in spinous and soft portions, scales ctenoid, arranged in double or triple columns along interradial membranes to ¼–½ of fin height. Scaly pad at base of dorsal fin formed by irregularly arranged, small, ctenoid scales extending from 2 nd or 3 rd spine to 5 th or 6 th ray. Reduced scaly pad on anterior portion of base of anal fin, from second spine to second or third ray, scales small, ctenoid. Caudal fin scaled in its entire surface, except the tip of rays, and membranes between D 2 and V 2, scales ctenoid. Accessory caudal fin extensions of lateral line between D 3 –D 4 and V 4 –V 5.
Fins. Dorsal XVIII 10 (1), XVIII 11 (4), XVIII 12 (2), XIX 10 (2), XIX 11 (5), XIX 1 (1); anal III 7 (2), III 8 (13). Dorsal spines increasing in length from first to sixth, equal length to ninth, then slightly shorter; lappets acutely pointed, up to ¼ the length of spines. Soft portion pointed, reaching the base of caudal fin, except for rays 4–5, reaching about ½ of caudalfin length; specimens smaller than 76.3 mm SL with rounded soft portion, not quite reaching caudalfin insertion. Anal fin with 3 rd soft ray moderately produced, reaching about ¼ of caudalfin length, otherwise scarcely reaches base of caudal fin. Caudal fin emarginate with lobes of approximately the same length and without filaments in studied specimens. Pectoral fin elongate, more or less triangular, longest at 4 th ray, reaching 1 st or 2 nd analfin soft rays, then progressively shorter ventrally. Pelvic fin triangular, first ray produced into a filament reaching 1 / 3 of caudal peduncle length; in one specimen 149.0 mm SL reaching 1 / 3 of caudalfin length; specimens 45.5 mm SL or less without produced rays, not reaching base of anal fin.
Teeth. Outer row of upper jaw with 19–31, slightly recurved, unicuspid teeth; slightly larger than in inner rows, extending along most of premaxillary length. Three to four inner rows with no clear gap separating them from outer row; teeth unicuspid, very thin, pointy, straight or slightly recurved. Inner rows parallel to outer on all its length, not forming a pad. Outer row of lower jaw with 7–28 unicuspid, blunt, slightly recurved, unicuspids; outer row restricted to median 1 / 3 of dentary length in holotype and large specimens, but extending farther in specimens 118.0 mm SL and smaller. Inner rows 3–4, separated from outer row by distinct gap; teeth long, thin, straight or slightly recurved unicuspids, smaller than outer row, and forming a pad on median region of dentary.
Gills. External rakers on first gill arch; 9 (2), 10 (4), 11 (4) on epibranchial lobe, 1 in angle and 11 (1), 12 (6), 13 (3) on ceratobranchial, none on hypobranchials. Microbranchiospines on the outer face of second to fourth arches; gill filaments with narrow basal skin cover.
Tooth plates. Lower pharyngeal tooth plate elongate ( Fig. 12View FIGURE 12); width of bone 84 % of length; dentigerous area 76 % of width; 30 teeth in posterior row, 11 in median row. Anteriormost teeth subconical, erect, laterally compressed; cusps on caudal half, slightly curved anteriorly, small rostral edge ridge; lateral marginal teeth as anteriorly on rostral edge, gradually flatter and smaller caudally; posteromedial teeth much larger, nearly round in circumference, medial or slightly posterior cusps, almost blunt. Ceratobranchial 4 with 5 toothplates with 4, 14, 6, 6 and 2 teeth.
Vertebrae. 14 + 19 = 33 (1), 14 + 20 = 34 (1), 15 + 19 = 34 (13); 11–13 epihemal ribs.
Color pattern in alcohol ( Fig. 10View FIGURE 10). Base color grayish yellow; nape, snout and upper lip dark gray, fading caudally to base color towards cheek; lower lip yellowish white. The only marking on the head is a vertical, dark mark in the corner of the preopercule, roughly parallel to its caudal edge, fading ventrally but continued into the interopercule in large specimens; indistinguishable or faded in specimens smaller than 70 mm SL. Gill cover slightly darker than base color. Flanks with four, broad, ventrocaudally directed, yellowishgray bars running from dorsal to ventral regions and disappearing below the lower lateral line ( Fig. 2View FIGURE 2 c). Bar 1 expands from the 4 th or 5 th scale, anterior to dorsalfin origin, to the base of the 5 th or 6 th dorsalfin spine, extends over the anterior portion of the flank and disappears in the region caudal to the pectoralfin insertion. Bar 2 extends from the 7 th or 8 th to the 11 th or 12 th dorsalfin spine, runs parallel to bar 1 and disappears approximately at the level of H 1. A blackish medial spot coincides with bar 2, extending rostrocaudally between the scales 10 and 13 of E 3 and dorsoventrally between the lower half of E 3 and E 1, such that the upper lateral line borders the dorsal edge of the spot. Bar 3 extends between the 13 th or 14 th dorsalfin spine to the 1 st or 2 nd soft ray, and runs parallel to bar 2 to H 1 or H 2, where it fades. Bar 4 extends between the base of the 3 rd and the last dorsalfin ray, and disappears in H 1; in some specimens bar 4 can start at the base of the 1 st or 2 nd dorsalfin ray and then appears merged with bar 3 at its base, but it is clearly separated ventrally ( Figs. 1View FIGURE 1, 2View FIGURE 2 c). A fifth, faded vertical bar can generally be distinguished covering the caudalmost 4 or 5 columns of scales of the caudal peduncle, but this bar tends to turn into a grayish colored area in larger specimens.
Dorsal fin hyaline to smoky, lappets dark gray or blackish; soft portion with white spotting on the interradial membranes, forming a more or less parallel pattern of horizontal stripes; in specimens 149.0 mm SL and smaller, 3 longitudinal, parallel, grayish stripes alternate with hyaline stripes along most of the dorsal fin, fading into an increasingly indistinguishable pattern rostrally. Anal fin dusky to grayish; two longitudinal, parallel darker stripes along soft portion of fin. Caudal fin dusky, with indistinct pattern ranging from round spots to longitudinal, whitish stripes, or a combination of both; specimens 45.5 mm SL and smaller with 2 or 3 blackish, vertical bands. Pectoral fin immaculate. Pelvic fin dusky to dark gray, spine and first ray whitish to slightly dusky.
Live colors ( Fig. 11View FIGURE 11). Live specimens show the same dark markings as described for preserved individuals. Snout gray turning bluish gray in the cheek, gill cover yellow with iridescent blue spots on each scale, lips yellowish white. Flanks are bluish silver with five longitudinal yellow stripes between base of dorsal fin and H 1. Dorsal and anal fins brownish red with iridescent blue longitudinal banding; pelvic fin bright red with iridescent blue banding, first ray white; caudal fin red, with large iridescent blue to white spots. An aquarium picture in Weidner (2000: 125, Fig. 3View FIGURE 3: Geophagus sp. “Rio Negro I”) shows unpaired fins and pelvic with a much brighter red than specimens photographed shortly after capture in the wild (HLF pers. obs.).
Distribution and habitat. Geophagus winemilleri is an uncommonly caught species (a revision of nearly 400 lots of Geophagus at MCNGAbout MCNG resulted in only 6 lots of this species), known only from the black waters of the lower Casiquiare drainage and the headwaters of the Río Negro in southern Venezuela ( Fig. 13View FIGURE 13). The scarcity of collections does not allow determining whether the species reaches the Orinoco mainstem. Individuals of this species are commonly sold in the market at the town of Barcelos, Brazil, in the middlecourse of the Río Negro (HLF pers. obs.). An undescribed species known in the German aquarium trade as G. sp. “Rio Negro I” or G. sp. “stripetail” ( Weidner 2000) corresponds well with the characters of G. winemilleri ; according to Weidner’s locality data, the species might extend as south as the Archipelago das Anavilhanas, near the confluence of the Rio Negro with the Amazonas.
Etymology. Named for Dr. Kirk O. Winemiller, who led the field expeditions to the Río Casiquiare region during which most of the type specimens of G. winemilleri were collected, and in recognition of his nearly two decades of contributions to ecology and tropical fish biology, many of which have been based on Venezuelan fishes.
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