Hemiancistrus votouro, Cardoso & Silva, 2004

Cardoso, Alexandre Rodrigues & Silva, José Francisco Pezzi da, 2004, Two new species of the genus Hemiancistrus Bleeker (Teleostei: Siluriformes: Loricariidae) from the upper rio Uruguai basin, Neotropical Ichthyology 2 (1), pp. 1-8 : 2

Hemiancistrus votouro , new species

Fig. 1

Holotype. MCP 33594 ,133.9 mm SL (female); Brazil: Rio Grande do Sul: Benjamin Constant: arroio Lageado Grande (tributary of the rio Passo Fundo , rio Uruguai basin), ca. 2.5 km NE from Votouro Indian Reserve (27°26’50"S 52°37’5"W), W. Bruschi Jr. & J. F. P. da Silva, 1 May 2002.

Paratypes. MCP 29661, 99.5-141.2 mm SL (3 males and 2 females) ; MNRJ 25920 , 99.5-136.3 mm SL (1 male and 1 female), collected with the holotype .

Diagnosis. Hemiancistrus votouro differs from all other Hemiancistrus except H. chlorostictus , H. meizospilos , H. megacephalus , and H. macrops by the presence of light dots on all fins and the lateral and dorsal portions of body. Hemiancistrus votouro differs from H. chlorostictus by the number of premaxillary teeth (61-79 vs. 30-54), by the larger adipose-fin spine (9.0-10.4% SL vs. 5.8-8.0% SL; Fig. 2 ), by the deeper caudal peduncle (11.0-11.8% SL vs. 9.6-10.4% SL), by the larger pectoral fin (36.2-41.3% SL vs. 30.6-35.4 % SL), by the larger exposed portion of cleithrum (11.2-12.7% SL vs. 9.3-10.6% SL; Fig. 3 ), by the narrower body at dorsal-fin origin (17.9-19.8% SL vs. 19.9-25.3% SL) and first anal-fin pterygiophore not exposed (vs. exposed). Hemiancistrus votouro is distinguished from H. meizospilos by the smaller orbit diameter (14.5-16.7% HL vs.16.7-21.0% HL; Fig. 4) and by the much smaller light markings (one to three dots per plate vs. one large dot occupying one to three plates and skin between them). Hemiancistrus votouro differs from H. megacephalus and H. macrops by the number of the light markings per body plate (one to three small dots per plate vs. only one large dot on each body plate).

Description. Meristic and proportional measurements in Table 1. Dorsal profile of body gently arched from snout tip to dorsalfin origin. Body narrowing progressively caudally from cleithrum. Trunk mostly straight and tapering slightly to caudal-fin base. Trunk and caudal peduncle mostly rounded in cross section, slightly flattened ventrally, more compressed caudally. Ventral surface flattened. Head slightly concave between orbits; dermal plates not carinate; upper margin of orbits (dorsolateral margin of frontal and sphenotic bones) slightly elevated. Snout broad and rounded anteriorly, slightly concave anterior to nares.

Odontodes not forming keels on lateral plates. Dorsal, supramedial, median, and inframedial plate rows complete from head to caudal fin. Abdomen without platelets, except for small patch of platelets between pectoral fins. Cheek plates present on lateral margins of head; snout plates reduced to few granular platelets, absent in rectangular area on snout tip; five rows of plates on caudal peduncle; 25-26 plates in medial plate row. Nuptial males with hypertrophied odontodes slightly larger on tip of pectoralfin spine. Cheek plates evertible with 13-24 hypertrophied odontodes with curved tips, longest odontode one and half times eye diameter (juveniles with fewer and shorter odontodes than adults). Opercle supporting about 15-20 small odontodes in juveniles and adults. Preopercle covered by small platelets.

Eyes small (14.5-16.7% HL), iris with large dorsal flap. Lips large, occupying most of ventral surface of head. Lower lip mostly covered with papillae, except for smooth band near its border. Maxillary barbel free and pointed, typically reaching about one third of way from its origin to gill opening. Some individuals with one or both barbels bifurcated.

Teeth small, bifid; medial cusp large, blade-like, and slightly rounded; lateral cusp minute, pointed, never reaching more than one third of mesial cusp length. Premaxillary teeth 61 to 79 (mean=71.4). Dentary teeth 61 to 84 (mean=71.8). Upper and lower jaw rami form angles slightly less than 180 o.

Dorsal-fin rays II,7; reaching adipose-fin origin when depressed. Dorsal fin originating at vertical line in front of pelvic-fin base; dorsal-fin spinelet V-shaped, locking mechanism functional. Pectoral-fin rays I,6; tip of spine reaching beyond half-length of pelvic-fin origin in both sexes, when depressed. Pelvic-fin rays I,5; tip of spine reaching slightly beyond anal-fin origin when depressed. Anal-fin rays I,4. First anal-fin pterygiophore not exposed. Caudal-fin rays I,14,I; caudal fin slightly truncate. Adipose-fin spine large and thick.

Color in alcohol. Dorsal and lateral surface of body and head dark gray, covered with small light dots, less numerous on caudal peduncle; one to three dots per body plate. Ventral body surface whitish. Fins dark gray with light dots on rays, occasionally also on membranes ( Fig.1 ). Some specimens with light dots almost imperceptible.

Distribution. Known only from type-locality. The arroio Lageado Grande, tributary of the rio Erechim, rio Passo Fundo system (upper rio Uruguai basin), Rio Grande do Sul, Brazil ( Fig. 5 ).

Ecological notes. Type-locality for this species is a 2-5 m wide stream, with rocky and sandy bottom, small rapids separated by pools and marginal vegetation moderately preserved.

Etymology. The specific name votouro (noun in apposition) is given in honor of the Votouro Indian Reserve , situated on Benjamin Constant, Rio Grande do Sul, Brazil.

Figures

Fig. 1. Hemiancistrus votouro, holotype, MCP 33594, female, 133.9 mm SL, arroio Lageado Grande, about 2.5 km NE from Votouro Indian Reserve (tributary of the rio Passo Fundo, rio Uruguai basin), Benjamin Constant, Rio Grande do Sul, Brazil.

Fig. 2. Scatter plot and regression line of adipose spine length as a function of standard length in Hemiancistrus votouro and H. chlorostictus.

Fig. 3. Scatter plot and regression line of length of exposed portion of cleithrum as a function of standard length in Hemiancistrus votouro and H. chlorostictus.

Fig. 5. Collection localities of H. votouro (triangle), H. meizospilos (square), H. punctulatus (hexagons), H. chlorostictus (circle) and H. fuliginosus (lozenges) in RioGran- de do Sul, Brazil, and Uruguay. Some symbols represent more than one lot or locality.Open symbols represent type localities.