Dolichancistrus cobrensis ( Schultz, 1944 )

Ballen, Gustavo A. & Vari, Richard P., 2012, Review of the Andean armored catfishes of the genus Dolichancistrus Isbrücker (Siluriformes: Loricariidae), Neotropical Ichthyology 10 (3), pp. 499-518 : 510-513

Dolichancistrus cobrensis ( Schultz, 1944) Fig. 4

Pseudancistrus pediculatus cobrensis Schultz, 1944: 299 , pl. 9, fig. b [type locality: Venezuela, Maracaibo basin, río Catatumbo basin, río Cobre, tributary to río Quinta, latter tributary to río La Grita, below La Grita]. - Gosline, 1945: 90 [in checklist of Neotropical catfishes]. - Mago-Leccia, 1970: 26 [ Venezuela; common name]. - Nijssen et al., 1982: 61 [type depository]. - Ferraris & Vari, 1992: 31 [type depository]. - Provenzano et al., 1998: 212 [type depository]. - Galvis et al., 1997: 96 [ Colombia, Lago Maracaibo basin, río Catatumbo; illustrated specimen misidentified].

Dolichancistrus cobrensis Isbrücker, 1980: 48 [shift to Dolichancistrus ]. - Burgess, 1989: 434 [in listing of species of Loricariidae ]. - Taphorn et al., 1997: 87 [ Venezuela]. - Isbrücker, 2001: 26 [in listing of species of Loricariidae ]. - Isbrücker, 2002: 15 [in listing of species of Loricariidae ]. - Fisch-Muller, 2003: 384 [in checklist of species of the Ancistrinae ]. - Armbruster, 2004a: 48, fig. 38 [in phylogenetic analysis of Loricariidae ]. - Lasso et al., 2004a: 173 [Lago Maracaibo basin]. - Ferraris, 2007: 235 [in checklist of catfishes].

Material examined. AUM 46306 , 22 , 4 , 56.1 -92.0 mm SL, Venezuela, río Orinoco drainage, río San Antonio, tributary of río San Jose de Bolivar-río Uribante system . AUM 30377 , 12 , 2 , 73.7 -76.0 mm SL, 3 cs, Venezuela, río Orinoco drainage, río San Antonio, tributary of río San Jose de Bolivar-río Uribante system . MCNG 541 , 2 , 30.9-54.1 mm SL, Colombia, Departamento de Norte de Santander, El Guayabal, Cúcuta-Chinácota road . MCNG 6470 , 4 , 36.0-55.0 mm SL, Venezuela, río Orinoco drainage, río Quirimari basin, quebrada La Legia, along river above Alquitrona at bridge to Liberta , 7°38’28”N 72°22’30”W . USNM 121036 , holotype, 78.0 mm SL, Venezuela, Estado de Táchira, Lago Maracaibo basin, río Cobre, tributary to río Quinta , latter tributary to río La Grita , below La Grita . USNM 121037 , paratypes, 4000 + (20, 10 males and 10 females, 47.6-63.1 mm SL), Venezuela, Estado de Táchira, Lago Maracaibo basin, río Cobre, tributary to río Quinta , latter tributary to río La Grita , below La Grita .

Diagnosis. Dolichancistrus cobrensis is distinguished from all congeners in the condition of the buccal papilla at the limit of the symphysis of the premaxillae (papilla absent vs. present, respectively). Dolichancistrus cobrensis further differs from D. atratoensis in the length of the pectoral-fin spine in mature males (extending beyond the tip of the adpressed pelvic fin vs. extending only midway down the length of the adpressed pelvic fin, respectively). Dolichancistrus cobrensis is additionally distinguished from D. carnegiei in the pattern of development of the enlarged odontodes along the margin of the snout in mature males (odontodes limited to the lateral margins of the snout vs. extending along the entire anterior and anterolateral margins of the snout, respectively). Dolichancistrus cobrensis further differs from D. fuesslii in the form of the distal margin of the pelvic fin in males (approximately smoothly convex vs. W-shaped, respectively), the pattern of distribution of the odontodes along the margin of the snout (odontodes located primarily along the lateral margin of the snout vs. extending along the entire anterior and anterolateral margins of the snout, respectively), and the extent of development of the odontodes on the dorsal portion of the pectoral-fin spine (extending over distal one-third of the spine vs. over distal one-half of the spine, respectively).

Description. See description under generic account for features general for Dolichancistrus . Largest examined specimen 92.0 mm SL. Morphometrics presented in Table 1 . Dorsal-fin rays ii,7 to 9; anal-fin rays ii,3; caudal-fin rays i,14,i; pectoral-fin rays i,6; pelvic-fin rays i,5. Preadipose plates 2 or 3; median plates 24 or 25. Buccal papilla within oral cavity absent at limit of symphysis of premaxillae. Enlarged odontodes in mature specimens present along anterolateral margins of snout but absent from anterior margin of snout. Odontodes along lateral margin of snout terminate distinctly short of anterior margin of cheek plates and not showing sexual dimorphism contrary to presence of dimorphism in other species of Dolichancistrus . Anterior margin of posterior cheek plate slightly separated from exposed portion of opercle. Anterior and posterior cheek plates square, of approximately same length. Hypertrophied odontodes on cheek apparatus recurved distally. Distal margin of pelvic fin smoothly convex. Adpressed pectoral-fin spine in mature males reaching posteriorly distinctly beyond tip of adpressed pelvic fin. Adpressed pectoral-fin spine of mature females reaching posteriorly to within area slightly beyond midpoint of adpressed pelvic fin and slightly short of tip of pelvic fin. Odontodes extending over nearly distal one-third of dorsal portion of pectoral-fin spine.

Coloration in alcohol. Overall ground coloration of head and body brownish on lateral and dorsal surfaces, lightly colored ventrally other than for brown upper lip. Head with patch of somewhat darker pigmentation in region anterior and ventral to orbit. Body in juveniles and smaller individuals with five distinct midlateral dark spots; anteriormost spot located slightly anterior to vertical through dorsal-fin origin and posteriormost spot on caudal peduncle. Midlateral series of dark spots of larger individual variably coalesce to give appearance of irregular midlateral stripe in some individuals. Dorsal surface of body with four saddle-like marks more obvious in smaller individuals. First mark located under anterior portion of dorsal fin, second under base of posterior dorsal-fin rays, third between dorsal and adipose fins, and fourth immediately behind posterior terminus of adipose fin. Contralateral third and fourth marks continuous across dorsal midline. Dorsal fin with alternating dark and light areas along rays that form irregular stripe-like pattern along length of fin. Dorsal-fin membranes lack dark pigmentation.Anal fin lacking dark pigmentation. Caudal fin with alternating dark and light areas on rays that form irregular transverse bar-like pattern across vertical extent of fin. Pectoral-fin spine with alternating dark and light regions on dorsal surface and with ventral surface lacking dark pigmentation. Pectoral-fin rays in smaller individuals without obvious dark pigmentation; larger specimens with alternating dark and light pigment pattern on lateral rays, but with medial rays and all membranes lacking dark pigmentation. Pelvic-fin spine with alternating dark and light areas; pattern more obvious in larger individuals. Pelvic-fin rays with some irregular darker areas on rays, but without distinct barring pattern. Pigmentation less obvious in smaller individuals.

Sexual dimorphism. Mature males and females of Dolichancistrus cobrensis have comparably developed odontodes along the lateral margins of the snout, contrary to the distinctly larger odontodes in males versus females in congeners. The pectoral-fin spines of mature males are proportionally longer than those of mature females.

Distribution. Dolichancistrus cobrensis is known from the southern portion of the río Catatumbo, a western tributary to Lago Maracaibo basin in Colombia and Venezuela, and localities in the upper río Apure in the río Orinoco basin ( Fig. 2 ).

Common name. Chorrosco, panche ( Mago-Leccia, 1970: 86).

Habitat. Schultz (1944: 299) reported that the types of the species were collected in “very swiftly running water among rubble to gravel.”

Remarks. In the description of Dolichancistrus cobrensis, Schultz (1944: 299) recognized it as a subspecies of Pseudancistrus pediculatus and differentiated his P. pediculatus cobrensis from P. pediculatus pediculatus (= Dolichancistrus fuesslii herein) by color pattern and minor mean meristic differences. Isbrücker (1980: 48) recognized Pseudancistrus pediculatus cobrensis as a species, Dolichancistrus cobrensis , without discussion of the basis for the transition to species status. Subsequent authors followed Isbrücker (1980). Our analysis revealed that P. pediculatus cobrensis and P. pediculatus pediculatus (= Dolichancistrus fuesslii ) differ in the form of the pelvic-fin margin, the relationship of the posterior cheek plate with the exposed portion of the opercle, the condition of the buccal papilla at the posterior limit of the premaxillary symphysis, the pattern of distribution of odontodes along the snout margin, and the development of odontodes along the dorsal portion of the pectoral fin. These forms are considered distinct, but with P. pediculatus pediculatus as a synonym of Dolichancistrus fuesslii (see Remarks under D. fuesslii ).

Galvis et al. (1997: 96) included a life coloration photo in their account of Pseudancistrus pediculatus cobrensis (the Dolichancistrus cobrensis of this study) from the río Catatumbo in Colombia. The illustrated specimen is rather an individual of Lasiancistrus , most likely L. guacharote which is the only member of the genus reported from that basin.

Figures

Fig. 4. Dolichancistrus cobrensis, MCNG 541, 54.1mm SL. Colombia, Departamento de Norte de Santander, El Guayabal, Cúcuta - Chinácota road; dorsal, lateral and ventral views.

Fig. 2. Map of Colombia showing localities for the species of Dolichancistrus. Dotted contours represent 1000 masl isoclines and striped areas indicate regions above 3000 masl. Some symbols represent more than one locality and/or lot of specimens. Dolichancistrus atratoensis (triangles; type locality = 1); D. carnegiei (squares; type locality = 2); D. cobrensis (circles; type locality = 3); D. fuesslii (inverted triangles; type locality = 4). Base map provided by John D. Lynch.