Ancistrus falconensis, Taphorn, Donald C., Armbruster, Jonathan W. & Rodríguez-Olarte, Douglas, 2010

Taphorn, Donald C., Armbruster, Jonathan W. & Rodríguez-Olarte, Douglas, 2010, Ancistrus falconensis n. sp. and A. gymnorhynchus Kner (Siluriformes: Loricariidae) from central Venezuelan Caribbean coastal streams, Zootaxa 2345, pp. 19-32 : 26-28

Ancistrus falconensis , new species

Figures 2 and 3 . Table 1 .

Holotype. MCNG 56067 118.8 mm SL (ex MCNG 54543) Falcón, El Hueque River, 11º09’41.4'' N, 69º 33' 24.9'' W, at bridge on highway from Churuguara to Coro, 19 October 2005. D. Taphorn, D. Rodríguez Olarte, J. Coronel, A. Amaro and H. Rivera.

Paratypes. All from Venezuela, Falcón state. Collected with holotype: MCNG 54543 (9) ANSP 189316 (2), AUM 50301, (2) ROM 84518, (2). CPUCLA 1638, 3, Churuguara-Coro highway at bridge 5 km below Hueque River cataracts at swim park, 11° 09' 41.1'' N, 69° 33' 24.8'' W, D. Rodríguez-O, A. Amaro, H. Agudelo 18 March 2006; 1890, 5, Hueque River at San Francisco swim park bridge, 24 October 2006, D. Rodríguez-Olarte, D. Taphorn, A. Amaro, J. L. Coronel, H. Agudelo and H. Rivera; 1891, 1, Falcón, Hueque River, near Colombia village, 27 October 2006, D. Rodríguez-Olarte, D. Taphorn, A. Amaro, J. L. Coronel, H. Agudelo and H. Rivera. MCNG 54538, 3, New main highway from Churuguara to Coro, San Pablo bridge, 19 October 2005, D. Rodríguez, D. Taphorn, J. Coronel, A. Amaro, H. Rivera; 54552 12, Hueque River in Quebracho, 19 October 2005, D. Rodríguez, D. Taphorn, J. Coronel, A. Amaro, H. Rivera.

Non types. CPUCLA 1126, 3, and MCNG 50457, 1, Tucurere dr., Aurarima River, Santa Lucia Sector, 10°34'08"N, 68°30'14"W, 23 March 2004, D. Rodríguez-O, A. Amaro, J. Coronel, L. Jara, H. Rivera.

Diagnosis. Ancistrus falconensis is distinguished from A. martini , the species occupying adjacent river drainages to the west of its range in the lake Maracaibo Basin (but separated by an expanse of arid coastal desert where no species of Ancistrus have been found) by color pattern: A. falconensis lacks distinct, light rounded spots on nose, tentacles and sides of the body (vs. present) and lacks dark spots on the spines and rays of all fins (vs. present).

Ancistrus falconensis can be separated from A. gymnorhynchus , the species in adjacent watersheds to the south of its range by almost always having light spots on the abdomen of adults (vs. abdomen almost always uniformly gray in adults) and by the following ratios in specimens greater than 60 mm SL: mouth W./pectoral spine L. (0.66–0.92 vs. 0.48–0.67, two specimens overlap), dentary tooth cup L./pectoral spine L. (0.21–0.26 vs. 0.14–0.220), and premaxillary tooth cup L./pectoral spine L. (0.15–0.22 vs. 0.22–0.32). Ancistrus falconensis can be distinguished from A. triradiatus , which is present in adjacent drainages to the south, but uncommon, by color pattern: A. falconensis lacks rows of dark spots on the dorsal, caudal, pectoral and pelvic fins (vs. present) and A. falconensis has small white spots on the abdomen (vs. absent).

Description. Morphometrics are given in Table 1 . Head and body robust, greatest body depth at or just anterior to nuchal plate. Dorsal profile of head and body convex from tip of snout to dorsal-fin origin, from there, nearly straight and sloping gradually down to preadipose plates where it angles slightly upwards. From posterior base of adipose spine slightly concave then straight to dorsal procurrent caudal-fin rays, where it angles dorsally ~40o to caudal fin. Ventral profile convex from behind mouth to below pectoral-fin insertions, abdomen slightly concave to anal-fin origin, then straight and sloping gently up towards caudal fin. Greatest width of body at opercular region, then narrowing progressively to end of caudal peduncle. Caudal peduncle deep and robust. Snout broadly rounded with large broad naked margin in males, less developed in females and juveniles. Tentacles well developed in mature males, present in all the regions defined by Sabaj et al. (1999) (cheek, posterior and anterior margin, antero-medial and postero-medial areas of unplated snout). Females with no or very few tentacles even in larger specimens. Eye moderate to large in appearance, dorsal margin of orbit not elevated, interorbital area slightly concave.

Hypertrophied cheek odontodes nine to 16 (mode 12), stout with tips hooked anteriorly, strongly evertible, the longest reaching to pectoral fin insertion, bases fleshy and thick. Oral disk ovate, wider than long. Lips covered with minute papillae, larger near centers of each lip, smaller near mouth and near margins. Lower lip moderate in size, not reaching pectoral girdle, its border covered with very small papillae. Maxillary barbel and buccal papilla very short. Dentary tooth row slightly curved, about equal with premaxillary tooth row. Teeth unevenly bifid, medial cusp much larger and spatulate, lateral cusp smaller, pointed, sometimes equal in length to main cusp in worn teeth but usually one third its length.

Exposed part of opercle roughly an elongate triangular and bearing short stout odontodes. Mid-dorsal plates 14(1) 15(1) 16(3), 17(5), 18(13), median plates 21(2), 22(14), 23(7); mid-ventral plates 16(1), 17(4), 18(15), 19(1), 20(2); plates bordering dorsal-fin base 7(21), 8(2); plates between dorsal and adipose fins 6(10), 7(13); preadipose plates: 1(23). Supraoccipital with margins between surrounding bones and plates usually clearly visible. Nuchal plate small and curved posterolaterally. Five series of lateral plates. Mid-dorsal plate series ending at vertical through preadipose plate, mid-ventral series ending at vertical through adiposefin spine. Last plate in median series only slightly smaller than penultimate plate, base of caudal fin with three or four small platelets after main series, then about eight roughly triangular platelets covering bases of caudalfin rays. Tiny odontodes present on body plates, largest on posterior margins of plates. All fin spines with minute odontodes, more developed on pectoral-fin spine of males. All fin rays with tiny odontodes on rays. Abdomen entirely devoid of plates; no exposed platelets anterior to anal-fin spine nor near pectoral-fin insertions.Dorsal-fin origin situated slightly anterior to vertical through pelvic-fin insertion. Tip of adpressed dorsal fin reaching preadipose plate. Adipose fin with stout spine and well-developed adnate membrane that adheres to plate just anterior to first procurrent caudal-fin ray. Pectoral spine extending to anterior third on pelvic-fin spine. Anal fin well developed, short; first anal-fin pterygiophore covered by skin. Caudal fin with oblique posterior margin, spines and first dorsal and ventral rays slightly longer than others. Ventral caudal-fin spine extends posteriorly following horizontal profile of caudal peduncle in preserved specimens. Fin-ray formulae (N=22): dorsal i,7; pectoral i,6; pelvic i,5; anal I,3 (1), i,4(21); caudal i,14,i. Caudal procurrent rays: dorsal: 3(1), 4(2), 5(19); ventral: 3(13), 4(8), 5(1).

Color in alcohol. Body base color gray, brown or tan. Dorsal part of head and body with small, rounded light spots in life, seldom retained, except in recently preserved material. Abdomen in specimens over 60 mm SL with small round light spots, usually retained in preserved material. Ventral part of head and caudal peduncle usually paler, not spotted. Dorsal fin usually with black pigment at base of first membrane, often forming vertically elongate spot. Caudal fin gray with light dorsal and ventral tips on spine and rays. Some specimens with numerous small and inconspicuous paler spots on rays of paired fins. Lips cream color or light gray to whitish.

Distribution. Venezuela, Falcón state, Hueque and Ricoa river drainages ( Figure 2 ). This species occupies upland streams, usually with clear water and rocky substrates.

Etymology. Named for the Venezuelan state of Falcón, where the type locality is found.

Figures

FIGURE 2. Collecting localities of Ancistrus gymnorhynchus (circles) and Ancistrus falconensis (triangles). White symbols indicate type localities. Red stars indicate major cities.

FIGURE 3. Holotype of Ancistrus falconensis n. sp. MCNG 56067.