Ancistrus vericaucanus, Taphorn, Donald C., Armbruster, Jonathan W., Villa-Navarro, Francisco & Ray, C. Keith, 2013

Taphorn, Donald C., Armbruster, Jonathan W., Villa-Navarro, Francisco & Ray, C. Keith, 2013, Trans-Andean Ancistrus (Siluriformes: Loricariidae), Zootaxa 3641 (4), pp. 343-370 : 364-366

Ancistrus vericaucanus , new species, Taphorn, Armbruster, Villa-Navarro and Ray

( Fig. 12 )

Holotype. MPUJ 6020 (1, 72.1 mm SL) Colombia, Departamento Valle del Cauca, Cauca River drainage, Finca Santa Barbara, río La Vieja, 1278 masl, 7 Nov. 2006. 4.59222o, -75.778667o.

Paratypes. MPUJ 3023 (6, 46.8-70.5 mm SL), collected with holotype; IUQ 2814 (1, 67.8 mm SL) Colombia, Departamento Valle del Cauca-Quindío, Cauca River drainage, Quebrada La Paloma, tributary of the Roble River, in "Montaña del Ocaso" Nature Preserve, La Vieja River drainage, upper Cauca 4.579722°, -75.849722°, 1103 masl; IUQ 3153 (1, 58.3 mm SL) Colombia, Departamento Quindío, Quebrada El Broche, tributary of the Barragán River, La Vieja River drainage, upper Cauca, 4.36556°, -75.771944, 1114 masl.

Diagnosis. Ancistrus vericaucanus can be diagnosed from all other trans-Andean Ancistrus by having two to three preadipose plates (vs. usually one, occasionally two in most species and four to five, occasionally three, in A. tolima ); and from all other trans-Andean Ancistrus except A. tolima by having the pectoral fin maximally reaching pelvic-fin spine when depressed ventral to pelvic fin (vs. pectoral fin reaching past middle of base of pelvic fin when depressed ventral to pelvic fin). Ancistrus vericaucanus can further be separated from A. caucanus by having a dentary tooth cup length to SL ratio of 4.7–5.3% (vs. 5.9–7.7%; Fig. 3 B); from A. centrolepis by lacking one to three rows of enlarged odontodes on the lateral plates and no odontodes on lateral plates longer than half the width of the supporting plate (vs. rows of odontodes present with some odontodes almost as long as the supporting plate is wide); from A. galani by having fully developed eyes and pigment (vs. eyes reduced and pigment absent or reduced); from A. martini by having a head-eye length to snout length ratio of 72.3–88.7% (vs. 53.9–72.1% in specimens greater than 60 mm SL; Fig. 3 C), dark spots on the fins relatively large forming three to four irregular bands on the caudal fin (vs. six to nine irregular bands) and three five spots along the pectoral-fin spine (vs. seven to nine spots); and from A. tolima by having an adipose-fin membrane, usually having two to three, occasionally one, preadipose plates (vs. four to five, occasionally three), and a dentary tooth cup length to SL ratio of 4.7–5.3% (vs. 5.7–9.1%; Fig. 3 B).

Description. N=10. Morphometrics given in Table 4 . Size range this study: 47–72 mm SL.

A relatively small Ancistrus , body broadest anteriorly, greatest body width just posterior to opercles, when spines extended or just behind pectoral-fin insertions if spines closed; then narrowing progressively to end of caudal peduncle. Head and body depressed, greatest body depth just anterior to dorsal-fin origin. Caudal peduncle deep, robust, compressed posteriorly. Dorsal profile of head ascending steeply in convex arc from tip of snout tip to just posterior of orbits, then ascending in gentle concave are to dorsal-fin origin. From there, descending in gently convex arc to just posterior of adipose-fin posterior margin, and then gently ascending to caudal fin. Ventral profile flat to slightly convex from tip of snout to pelvic-fin insertions, then ascending to anal-fin origin, and less steeply to caudal-fin base

Head wide, interorbital width equal or slightly less than head depth, slightly more than half of head length. Snout rounded with large broad naked margin in males, less wide in females and juveniles. Snout length about onehalf head length. Eye moderate in size, interorbital area slightly convex. Oral disk ovate, wider than long. Lips covered with minute papillae, larger near mouth. Lower lip moderate in size, not reaching gill aperture, its border covered with very small papillae. Maxillary barbel very short, its length less than orbit diameter. Dentary tooth row straight, about same size as premaxillary tooth row. Teeth numerous (29–50 per jaw ramus), asymmetrically bifid, medial cusp much larger and spatulate, lateral cusp minute and pointed, usually not reaching more than half length of medial cusp, equal in worn teeth. Hypertrophied cheek odontodes strongly evertible, 16–20, stout with tips hooked anteriorly, bases encased in thick fleshy sheaths. Exposed part of opercle small, roughly in shape of narrow triangle with few odontodes. Head smooth, bones on back of head not carinate; supraoccipital with margins between surrounding bones and plates usually clearly visible. Lateral plates not carinate, lateral line pores distinctly visible, horizontally elongate.

Ventral surface of head and abdomen naked, no exposed platelets anterior to anal-fin spine. Nuchal plate small and curved posterolaterally. No enlarged odontodes at edge of lateral plates. Five series of lateral plates anteriorly, three series on caudal peduncle, middorsal and mid-ventral plate series end on caudal peduncle beneath adipose-fin spine. Last plate in median series slightly smaller than penultimate plate, base of caudal fin with vertical column of about four small platelets after main series, and about six roughly triangular platelets covering bases of caudal-fin rays.

Dorsal-fin origin situated anterior to vertical through pelvic-fin insertion. First dorsal-fin ray not elongate, just slightly longer than snout length; last dorsal-fin ray reaching first preadipose plate when depressed. Adipose-fin spine (if present) embedded, oriented parallel to horizontal axis of body, membrane absent, not visible beneath spine. Pectoral spine short, stout, reaching past pelvic-fin insertions but only to anterior third of pelvic fins. Anal fin small but well developed; base of first anal-fin pterygiophore covered by skin, its origin below or posterior to vertical through base of last dorsal-fin ray. Pelvic fins reaching well past anal-fin origin, inserted posterior to vertical through first branched dorsal-fin ray. Caudal fin truncate, lower lobe slightly longer than upper.

Tiny odontodes present on body plates, largest on posterior margins of plates. All fin spines with small odontodes, more developed in pectoral-fin spine of males. All fin rays with tiny odontodes on rays.

Mid-dorsal plates 17(2), 18(1), 19(4), 20(3); median plates 22(1), 23(7), 24(2); mid-ventral plates 17(2), 18 3, 19(2), 20(2), 21(1); plates bordering dorsal-fin base 6(1), 7(9); plates between dorsal and adipose fins 3(1), 4(6), 5(2), 7(1); preadipose plates: 2(7), 3(3). Fin-ray formulae invariable (N=10): dorsal i,7; pectoral i,6; pelvic i,5; anal i,4; caudal i,14,i. Caudal procurrent spines: dorsal: 3(3), 4(2), 5(5), ventral: 3(8), 4(2).

Color in alcohol. ( Fig. 12 ) Dorsal and lateral base color dark gray to brown mottled with light brown, and sometimes lighter brown spots concentrated top of head. Soft nose and tentacles also dark with irregular lighter spots. Some plates of dorsum dark brown edged in lighter brown. All fins with three-four alternating dark brown to black and light brown spots present on spine and branched rays. Fin membranes usually not spotted except on caudal fin. Dark spots on rays of caudal fin not aligning to form vertical bars or arcs. Ventral surface of head and abdomen tan with large irregular lighter spots and vermiculations. Oral disk whitish. Base of caudal fin with light tan area on dorsal and ventral margin of caudal peduncle, but not forming complete light vertical bar. Color in life not available.

Distribution. Upper Cauca River, a tributary to the Magdalena River in Colombia.

Etymology. veri is Latin for true, caucanus refers to Ancistrus caucanus , a species thought originally (but apparently mistakenly), to be from the Cauca River of northern Colombia. As it turns out, Ancistrus caucanus occurs in the Magdalena River drainage, not in the Cauca. This new species then, is the true inhabitant of the Cauca River streams, hence the name vericaucanus .

Remarks. This species is not sympatric with any other species of Ancistrus , and is endemic to the Cauca River in Colombia. See A. caucanus remarks for more information.

Figures

FIGURE 3. Diagnostic biplots for species of Ancistrus.

FIGURE 12. Holotype of Ancistrus vericaucanus, MPUJ 6020 (72.1 mm SL).