Lamontichthys llanero Taphorn & Lilyestrom, 1984

Fig. 11

Lamontichthys llanero Taphorn & Lilyestrom, 1984a: 96-98, fig. 2, table 1 [original description; type locality: “ Venezuela, Portuguesa, río Guanare Viejo cerca de La Hoyada”]; Provenzano et al., 1998: 11, 21, 23 [type listed]; Eschmeyer, 1998: 923 [listed]; Armbruster, 2004 [phylogenetic relationships]; Armbruster, 1998: 665, table 1 [analysis of the digestive tract]; Mojica, 1999: 562 [listed]; Isbrücker, 2001: 29 [listed]; Ferraris Jr., 2003: 336 [listed]; Ferraris Jr., 2007: 264 [listed]

Diagnosis. Lamontichthys llanero is distinguished from all other congeners, except L. filamentosus, by having the lower lip semicircular in shape (vs. semi-oval, Fig. 9). Lamontichthys llanero differs from L. filamentosus in the narrower head (82.6-96.9%, vs. 97.4-111.1% HL). Lamontichthys llanero has the interorbital distance larger (n = 36) and only rarely equal (n = 2) to the distance from the orbit to the exposed border of the cleithrum. All other species of Lamontichthys possess the interorbital distance shorter or equal to the distance from the orbit to the exposed border of the cleithrum (Fig. 6).

The presence of two plates between the base of the last pelvic-fin ray and the anterior border of the anus (vs. one) (Figs. 1 and 5), and 7 to 10 lateroventral thoracic plates in specimens larger than 50 mm SL (vs. 5 to 6) further distinguishes L. llanero from L. maracaibero . Specimens of Lamontichthys llanero larger than 70 mm SL further differs from L. stibaros, L. avacanoeiro, and L. parakana; in having the snout entirely covered with plates or with only a round inconspicuous area lacking plates at its anterior tip (vs. with a large oval area lacking plates), and teeth with short cusps (vs. long) (Fig. 3). Lamontichthys llanero further differs from L. avacanoeiro in the longer first branched dorsal-fin ray, in specimens larger than 50 mm SL (30.9-40.5%, vs. 21.9-26.0% SL). Morphometric and meristic data are presented in Table 2.

Geographic distribution. Río Orinoco basin (Fig. 2).

Comments. Lamontichthys llanero has been collected near the margins of rivers varying from less than 10 m until 1 km of width, in areas with muddy waters, and sand or mud in the bottom (F. Provenzano, pers. comm.).

Material examined (37 specimens; 32.4-162.5 mm SL): Colombia: Meta: ANSP 131621, 1, 118.3, río Guayariba; ANSP 131617, 1, 106.2, confluence of río Guayariba with río Metica; ANSP 131619, 1, 96.3, río Metica; ANSP 131623, 1, 84.0, río Negro; Venezuela: Apure: INHS 28391, 1, 45.2, Caño. Barinas: INHS 29957, 5 (of 9), 91.1-132.4, 1cs *, 105.2, tributary of río Masparro; INHS 29900, 3, 88.0-116.7, río Masparro. Cojedes : INHS 28989, 2, 32.4-86.1, río San Carlos; INHS 32029, 1, 87.9, río San Carlos; INHS 60236, 1, 36.3, río Pao. Guarico : MBUCV-V 31534 7, 86.3-152.2, río Orituco; ANSP 131624, 2, 64.2-75.7, 18 km SSE Calabozo; ZMA 120469, 1, 146.8, río Guarico basin . Portuguesa: INHS 28649, 1, 162.5, Mata Larga, río Portuguesa; INHS 35687, 3 (of 4), 117.5-144.0, río Portuguesa, 3 km NE El Barriero ; INHS 31993, 1, 80.1, río Guanare; INHS 69262, 3 (of 4), 81.2-124.9, Caño Los Manires; INHS 34097, 1, 70.3, río Tucupido; INHS 54657, 1, 110.7, río Portuguesa; INHS 56125, 1, 110.1, río Guanare; INHS 56151, 3 (of 4), 97.3-150.2, río Portuguesa .