Probolodus sazimai

description

Description. Morphometric data presented in Table 1. Body moderately compressed and deep, less so in individuals of less than 150 mm SL, greatest body depth within region delimited anteriorly by vertical through insertion of pelvic fin and posteriorly by vertical through origin of dorsal fin. Average body depth variable among population samples, but with broad overlap in ranges among examined samples. Dorsal profile of head distinctly convex from margin of upper lip to vertical through posterior nostril, straight to very slightly convex from latter point to tip of supraoccipital spine. Dorsal profile of body moderately convex from tip of supraoccipital spine to origin of dorsal fin, straight and posteroventrallyslanted along base of dorsal fin, straight to slightly convex from posterior terminus of base of dorsal fin to adipose fin, and slightly concave along caudal peduncle. Broad middorsal ridge present along predorsal region of body, with ridge less obvious anteriorly. Dorsal region of body between posterior terminus of dorsal fin and adipose fin transversely rounded overall, but slightly flattened middorsally in some individuals. Ventral profile of head slightly convex anterior

Taxonomy of Probolodus Eigenmann, 1911 (Characiformes: Characidae) with description of two new species, and comments about the phylogenetic relationships and biogeography of the genus

diagnosis

Diagnosis. Probolodus sazimai differs from its two congeners, P. heterostomus e P. oyakawai (new species) by the following characteristics: six transverse series of scales from insertion of pelvic fin to lateral line (vs. seven / eight); 12 scales along middorsal line between posterior termination of base of dorsal fin and adipose fin (vs. 14 - 17 and 13 - 16, respectively); presence of two pairs of uroneurals (vs. absent or just one pair) (Fig. 8 a); anterior margin of the hypurals 2 and 3 in contact, not fused (vs. hypurals 2 and 3 distinctly separate) (Fig. 8 a); end piece or stay of the dorsal fin leaning against or fused in the last pterygiophore (vs. somewhat removed of the last pterygiophore) (Fig. 8 b); fourth basibranchial completely cartilaginous (vs. ossified) (Fig. 9 a); dorsal margin of the opercle more elevated than the hyomandibular (vs. opercle and hyomandibular practically aligned) (Fig. 9 b); anteromedially projection of the mesethmoid wide, separating completely the premaxillary (vs. short projection, not separating completely the premaxillary). It may be further separated from P. heterostomus by presence of 36 - 43 perforated scales on the lateral line (vs. 45 -

Taxonomy of Probolodus Eigenmann, 1911 (Characiformes: Characidae) with description of two new species, and comments about the phylogenetic relationships and biogeography of the genus

distribution

Distribution. Probolodus sazimai is known to occur in the rios Itapemirim and Doce basins (Espírito Santo and Minas Gerais states, respectively), southeastern Brazil. (Fig. 2). Ecological notes. Ctenoid and cycloid fish scales were observed in the stomach contents and between gill rakers of one specimen (MCP 13813, 1, 43.5 mm SL). No other items could be identified, possibly due to their advanced state of decomposition. Leaf fragments, insects and scales were observed in the oral cavity of three specimens preserved in alcohol (LBP 3433, 1, 45.1 mm SL; MCP 13813, 2, 36.8 - 54.4 mmSL).

Taxonomy of Probolodus Eigenmann, 1911 (Characiformes: Characidae) with description of two new species, and comments about the phylogenetic relationships and biogeography of the genus

etymology

Etymology. The species name, sazimai, is in honor of Ivan Sazima from Museu de Zoologia of UNICAMP (ZUEC-PIS), in appreciation of his contributions to our knowledge of the Neotropical lepidophagous caraciforms. Notes on phylogenetics relationships and biogeography of Probolodus The monophyly of Probolodus is supported by five exclusive characteristics, and three non-exclusive characteristics. Of all the characteristics shared among species of the genus, there are at least two exclusive characteristics, such as the presence on premaxillary and dentary of tricuspid teeth, with median cusp greatly developed and pointed outward, most probably related to the lepidophagous habit these species (Fig. 1 a-c). The genera of Neotropical characiforms Bryconexodon, Catoprion, Exodon, Roeboexodon, Roeboides, and Serrabrycon also exhibit specialized dentitions favoring the lepidophagous habit, such as pointed by Sazima (1977), Sazima & Uieda (1980), Sazima & Machado (1982) and Sazima (1983). However, specialized teeth directed out of the mouth is a diagnostic characteristic which allows easy recognition of lepidophagous taxa, although, the shape, number and the differential arrangement these coni

Taxonomy of Probolodus Eigenmann, 1911 (Characiformes: Characidae) with description of two new species, and comments about the phylogenetic relationships and biogeography of the genus