Leptophilypnion, a new genus with two new species of tiny central Amazonian gobioid fishes (Teleostei, Eleotridae)
Tyson R. Roberts.
aqua, International Journal of Ichthyology, pp. 85-98, Volume 19, Issue 2 – 26 April 2013
Leptophilypnion pusillus new genus and species is described from three specimens, 8.4-9.1 mm standard length, collected in the central lowland Amazon basin at a single locality near Santarém. A gravid female 9.1 mm standard length has 5-6 oval eggs 0.5 mm long. The new fish is distinguished readily from the only other previously described Amazonian eleotrids, the three species of the genus Microphilpnus Myers 1927, by adults having head and body anterior to second dorsal fin scaleless; two innermost rays of each pelvic fin simple and filamentous, extending to or beyond anal fin origin; head relatively large and snout truncate or blunt (vs. head smaller and snout relatively pointed); body and caudal peduncle relatively short and deep instead of slender; and only 5 instead of 6 branchiostegal rays. A second species of the new genus, L. fittkaui, is described from 10 specimens 8.9-9.7 mm from a locality near Manaus.
Leptophilypnion is perhaps most closely related to the Central American freshwater eleotrid genus Leptophilypnus Meek and Hildebrand 1916, particularly the species L. guatemalensis, with which L. pusillus agrees in having the unusual dorsal fin spine pterygiophore to neural spine insertion formula of 3-12201 and 10+16=26 vertebrae. L. fittkaui, a somewhat stouter species, has 3-121110 and 11+15=26.
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