Pimelodus grosskopfii Steindachner, 1879

Villa-Navarro, Francisco Antonio, Acero, Arturo & Cala, Plutarco Cala, 2017, Taxonomic review of Trans-Andean species of Pimelodus (Siluriformes: Pimelodidae), with the descriptions of two new species, Zootaxa 4299 (3), pp. 337-360 : 344-348

Pimelodus grosskopfii Steindachner, 1879

Pimelodus (Pimelodus) grosskopfii Steindachner, 1879: 194 . Type locality: Río Cauca, Colombia. Syntypes: NMW 45781 (4), NMW 45782 (1).

Pimelodus longifilis Posada, 1909: 294 . Type locality: río Cauca, Colombia. No type material known.

Diagnosis. Pimelodus grosskopfii differs from P. blochii and other trans-Andean species, except P. crypticus , in having a longer adipose fin (24.0–28.2% SL vs. 14.1 –22.6% SL) ( Fig. 7 ); it differs from P. crypticus in having a shorter predorsal distance (33.0–37.3% SL vs. 37.5–40.7% SL) and a shorter head (22.8–25.9% SL vs. 26.4–30.4% SL) ( Fig. 8 ); it differs from P. blochii in having a greater interorbital width (34.4–41.9% HL vs. 26.0–33.0% HL) and a smaller eye (12.1–19.2% HL vs. 22.1–27.5% HL). Additionally, it differs from P. blochii , P. crypticus n. sp., and P. yuma n. sp. in having the body with dark spots (vs. without spots).

Description. N=30. Morphometric data presented in Table 2. Body deeper than wide; roof of cranium ornamented with conspicuous granules and striations. Eye diameter less than interorbital width. Snout slightly convex, projected beyond mandibular symphysis. Mouth subterminal, when closed a little more than half premaxillary tooth patch exposed, those teeth conic, small and narrow. Fontanel open from mesethmoids to frontal, ending at vertical through middle of eye. Maxillary barbels almost reach caudal fin. Inner mental barbels reach pectoral-fin bases; outer almost reaching pelvic-fin bases.

Table 2. Morphometric data for P. yuma n. sp., P. crypticus n. sp., P. grosskopfii , and P. punctatus expressed (except for whole-fish standard length, mm) in percent standard length (%SL) or head length (%HL).

Pimelodus Pimelodus Pimelodus Pimelodus yuma crypticus grosskopfii punctatus 144 13 30 45 …continued on the next page Dorsal fin lepidotrichia II,6; the first a spinelet narrow and angular, spine strong, slightly curved and pointed. Adipose fin long, its margin rectangular, anterior apex at a vertical just anterior to first unbranched anal-fin ray. Pectoral fin I,8; spine strong, sharp, pointed and forming slight arc. Pelvic fins i,5 with first branched ray longest, inserted at vertical through base of penultimate dorsal-fin ray. Anal fin iii–iv,7–9; first branched ray longest. Caudal fin i,15,i; forked, lobes sharp pointed, the dorsal equal to or slightly longer than ventral.

Lateral line complete, extending beyond caudal-fin base for half-length of middle caudal-fin rays. Cleithral process extensive, strong, triangular, posterodorsal and ventral margins slightly convex. Apparently without sexual dimorphism.

Color in alcohol. ( Fig. 6 ) Body silvery or light tan; head, dorsal region and sides of body with small dark spots distributed uniformly; on head these spots cover cheeks and snout. Ventral region light tan to white. Base of dorsalfin spine dark. All fins pigmented light, tan darkening distally; ventral lobe of caudal fin without dark diffuse band; distal margin of adipose fin hyaline; dorsal surface of maxillary barbels tan.

Distribution. Magdalena, Cauca, and San Jorge River drainages ( Fig. 4 ).

Figures

FIGURE 4. Distributions of trans-Andean Pimelodus. Symbols may represent more than one collection. Yellow symbols indicate type localities. Pimelodus coprophagus (cross), Pimelodus navarroi (diamond), Pimelodus grosskopfii (pentagon), Pimelodus punctatus (star), Pimelodus crypticus n. sp. (triangle), and Pimelodus yuma n. sp. (circle).

FIGURE 6. Pimelodus grosskopfii CZUT-IC 2019, 321.2 mm SL, Prado dam, Lozanía sector, Prado River drainage, Magdalena River Basin, Departament of Tolima, Colombia. Photo by J. E. García-Melo

FIGURE 7. Scatter plot illustrating shorter adipose fin-base relative to standard length in trans-Andean Pimelodus.

FIGURE 8. Scatter plot illustrating percent head length (% HL) vs. standard length (% SL) in P. grosskopfii (diamond) compared to P. crypticus (squares).