A new species of the Hoplias malabaricus species complex (Characiformes: Erythrinidae) from the La Plata River basin

ROSSO, J.J.; MABRAGAÑA E.; GONZALEZ-CASTRO M.; DELPIANI, S. M.; AVIGLIANO, E.; SCHENONE, N.; DIAZ DE ASTARLOA, JUAN M

CYBIUM

SOC FRANCAISE D ICHTYOLOGIE

Lugar: Paris; Año: 2016 vol. 40 p. 199 - 208

0399-0974

Hoplias malabaricus is one of the 12 valid species in the genus Hoplias, the most diverse genusamong the Erythrinidae. During the last decades, cytogenetic studies had shown that this species represents awell-populated species complex. The new species of the Hoplias malabaricus group is described from the Uruguay,Paraná and Paraguay Rivers, in Argentina and Brazil. The Y-shaped configuration of the medial margins ofdentaries easily separates Hoplias misionera n. sp. from all the remainder species of Hoplias (parallel-shaped inH. lacerdae group and H. aimara and V-shaped in H. malabaricus group). Hoplias misionera n. sp. can be furtherdistinguished from H. malabaricus by the total number of dorsal (14-16 vs 14) and pectoral (12-14 vs 11) finrays and the number of scales in lateral line (40-43 vs 38-39). Hoplias misionera n. sp. differs from H. microlepisin unbranched (2-4 vs 2) dorsal-fin rays, the number of scales along lateral line (40-43 vs 43-47) and a lowernumber of scales around the caudal peduncle (20 vs 22-24, usually 24). Hoplias misionera n. sp. differs fromH. teres by number of scales in lateral line (40-43 vs 38), number of total (14-16 vs 13) and unbranched (2-4 vs3) dorsal-fin rays and pectoral (12-14 vs 13-15) fin rays, total vertebrae count (39-40 vs 42), larger dorsal-finbase (16.7-20.9 vs 16.2-17.6% SL) and body depth (20.6-25.4 vs 17-20.6% SL). Finally, Hoplias misionera n.sp. can be distinguished from the recently described H. mbigua by a distinctly shorter snout length (20.4-24.7 vs25.2-28.6% HL) and lower pre-nasal distance (12.5-16.2 vs 15.2-18.4% HL). Hoplias misionera further differsfrom H. mbigua by dorsal profile of head markedly straight vs dorsal profile of head markedly concave; lowerjaw with either brown bands, dots or blotches vs always five distinctive transversally brown bands; infraorbital5 lacking pores in laterosensory canal vs infraorbital 5 with one pore, last vertical series of scales on caudalpeduncle forming marked curve vs forming a relatively straight line. Finally, colour pattern also contributes tothe discrimination between H. misionera and H. mbigua