A new species of the genus Hoplias (Characiformes, Erythrinidae), a tararira from the lower Paraná River, in Misiones, Argentina

Abstract

We describe Hoplias mbigua , a new species of the genus from the lower Paraná, in Misiones, with tooth-bearing plates on dorsal surface of basihyal and basibranchi- als and medial margins of contralateral dentaries converging towards the mandibular symphy- sis in ventral view, characters that permit to include the species in the H . malabaricus group. The presence of five brown bands transversely placed on lower jaw distinguishes the new species from its congeners, excluding H . microlepis (vs. lower jaw straight or with small black or brown dots uniformly distributed). The number of circunpeduncular scales in H . mbigua is 20 whereas H. teres and H. malabaricus have 18 circunpeduncular scales and H . microlepis 22-24 and 12-16 gill rakers on first epibranchial (vs. about 9). Hoplias mbigua has convex dorsal profile between head and dorsal fin whereas H . teres has straight dorsal profile. Hoplias mbigua has a large supraopercle, with its anterior margin contacting the in- fraorbitals 5 and 6 whereas H . cf. malabaricus has a short supraopercle, with an anterior margin scarcely extended before anterior opercular margin. Hoplias mbigua has a large tooth- plate on basihyal and basibranchials instead of two lines of tooth-plates at sides of bones in H . cf. malabaricus .