Hemiancistrus meizospilos, 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 : 4-6

Hemiancistrus meizospilos , new species Fig. 6

Holotype. MCP 34091, 148.4 mm SL (male); Brazil: Santa Catarina: Coronel Freitas: rio Chapecó (tributary of the rio Uruguai basin), Leandro Baucke , 20 May 2003.

PROOFS

Paratypes. MCP 34092, 72.4-149.1 mm SL (5 males, 14 females and 2 juveniles) ; MNRJ 25921 , 115.2 - 122.6 mm SL (4 males and 1 female) , collected with the holotype. MCP 34093, 119.1 mm SL (1 male) ; Brazil: Santa Catarina: Formosa do Sul, rio do Ouro (tributary of the rio Chapecó ), Alcione Cella, 2003 .

Diagnosis. Hemiancistrus meizospilos differs from all other Hemiancistrus except from H. chlorostictus , H. votouro , H. megacephalus , and H. macrops by the presence of light dots on all fins and the lateral and dorsal portions of body. Hemiancistrus meizospilos differs from H. chlorostictus and H. votouro by the much larger light markings (one large dot occupying one to three plates vs. one to three dots per plate) and from H. votouro by the larger orbit diameter (16.7-21.0% HL vs. 14.5-16.7% HL; Fig. 4). Hemiancistrus meizospilos is distinguished from H. megacephalus and H. macrops by the area that light dots occupying each body plate (one large dot occupying one to three plates and skin between them vs. one large dot occupying only one 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 with small patch of platelets between pelvic fins, and with larger patch of platelets between lower lip and area between pelvic fins, abdomen otherwise naked. Narrow band of minute platelets along ventral area between pectoral- and pelvic-fin origins. 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 plates in medial plate row. Nuptial males with hypertrophied odontodes slightly larger on tip of pectoral-fin spine. Cheek plates evertible with 10-15 hypertrophied odontodes with curved tips, longest odontode one and half times eye diameter (juveniles with fewer and shorter odontodes than adults). Opercle supporting about 15-27 small odontodes in juveniles and adults. Preopercle covered by small platelets.

Eyes small (16.7-20.1% 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 triangular, 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 50 to 66 (mean=57.2). Dentary teeth 48 to 67 (mean=58.4). Upper and lower jaw rami form angles slightly less than 180o.

Dorsal-fin rays II,7; not 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 approximately anal-fin origin when depressed. Anal-fin rays I,4. First anal-fin pterygiophore occasionally exposed in some specimens (not exposed in the holotype). 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 with large light dots; one dot occupying one to three plates and skin between them. Ventral body surface whitish. Fins dark gray with large light dots on rays, and occasionally also on membranes between fin rays ( Fig. 6 ). Juveniles with small light blotches on body.

Distribution. Hemiancistrus meizospilos is only known from its type-locality on the rio Chapecó system, tributary of the rio Uruguai (upper rio Uruguai basin), Santa Catarina, Brazil ( Fig. 5 ).

Etymology. From the Greek adjective meizon (masculine, nominative singular), comparative of megas (big, great), and spilos (dots), alluding to larger size of dots on comparison to smaller size on remaining white-spotted species of southern Brazil.

Figures

Fig. 6. Hemiancistrus meizospilos, holotype, MCP 34091, male, 148.4 mm SL, rio Chapecó (tributary of the rio Uruguai basin), Coronel Freitas, Santa Catarina, Brazil.

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.