Utiaritichthys esguiceroi, new species

Figs. 1-2

Holotype. LIRP 8184, 197.9 mm SL, Brazil, Mato Grosso State, rio Tapajós drainage, rio Juruena, nearby the município de Sapezal, 12º51’29"S 58º55’23"W, 03 Nov 2008,, R. J. Ilário, M. S. F. Arcifa & A. L. H. Esguícero.

Paratypes. LIRP 8185, 11 (2 c&s), 187.0-260.0 mm SL. MCP 46331, 3, 197.0-217.0 mm SL. MZUSP 109232, 3, 192.0-196.0 mm SL, same data as holotype .

Non-type material examined. Brazil, Mato Grosso State, município de Sapezal, rio Juruena, LIRP 8187, 15, 174.0-211.0 mm SL; LIRP 8188, 3, 187.0-192.0 mm SL, same locality as holotype . LIRP 9045, 13, 21.0-62.0 mm SL, PCH Cidezal, 13º22’39"S 59º00’57"W, 18 Mar 2008, R. J. Ilário. LIRP 9046, 10, 24.0-43.0 mm SL, PCH Parecis, 13º04’43"S 58º58’06"W, 19 Mar 2008, R. J. Ilário. LIRP 9047, 13, 105.4 -262.0 mm SL, PCH Sapezal, 13º16’10"S 59º01’26"W, 18 Mar 2008, R. J. Ilário. LIRP 9048, 14, 110.4 - 180.5 mm SL, PCH Parecis, 13º04’43"S 58º58’06"W, 19 Mar 2008, R. J. Ilário.

Diagnosis. Utiaritichthys esguiceroi differs from its congeners by the higher number of perforated scales on the lateral line (99-101, vs. 69-72 in U. sennaebragai, and 78-82 in U. longidorsalis), the higher number of prepelvic spines (17-19, vs. 9-10 in U. sennaebragai, and 28-31 in U. longidorsalis), the lower number of postpelvic spines (20-21, vs. 15-17 in U. sennaebragai, and 14 in U. longidorsalis), and also by the number of circumpeduncular scales (23-25 vs. 30-48 in U. sennaebragai, and 33-35 in U. longidorsalis). Furthermore, the new species differs from U. longidorsalis by having larger interdorsal width (11.8-15.6 vs. 7.1-7.9% of SL), and larger adipose-fin base length (4.2-5.8 vs. 3.7-3.8% of SL).