Systematics and biogeography of the tropical sea catfishes of the New World (Siluriformes: Ariidae)

Abstract

Ariidae (Siluriformes), widely distributed in world tropical shelves, includes 150-200 species, one third endemic to the New World. Males practice mouthbrooding of eggs and embryos. To study the phylogeny of neotropical ariids, a morphological matrix [26 species (three outgroup, 23 ingroup), 56 characters) was used. The strict consensus tree of 12 parsimonious trees is 85 steps long. Ariidae includes two subfamilies. Galeichthyinae includes one species endemic to the eastern Pacific, Galeichthys peruvianus. Ariinae has three New World lineages. Notarius includes seven species in the western Atlantic, Colombia to southern Brasil, and seven in the eastern Pacific, Baja California to Peru. Cathorops has two lineages, a monotypic for C. dasycephalus, from eastern Pacific, and other for the rest. There are six species of Cathorops in western Atlantic and seven in eastern Pacific. The tribe Ariopsini, 24 species, is defined by two states from the otolith. The tribe is divided in two unities. The first includes Bagre, four species, and Occidentarius platypogon, endemic to the eastern Pacific. Western Atlantic Bagre are known from Massachussetts to Brasil; the eastern Pacific species go from California to Peru. The other ariopsin unity includes Ariopsis, five species, and Sciades, six species. Ariopsis ranges in western Atlantic from Massachussetts to Venezuela and in eastern Pacific from Mexico to Peru. Sciades includes five western Atlantic species, Colombia to Brasil, and one eastern Pacific species, Mexico to Peru. The freshwater genus Potamarius , four species, three from western Atlantic rivers and one from Ecuadorian rivers, is the sister taxa to Ariopsis. Genidens , four western Atlantic species, Brasil to Tierra del Fuego, is related to ariopsins. The hypothesis for Bagre produced with the morphological matrix coincides with the topology from morphometric techniques; three phylogenetic hypotheses found with molecular techniques were different. Bagre pinnimaculatus is the sister species to B. bagre, both are the most derived species; B. marinus is the most generalized species. Other transisthmian speciation events were found within the genera Notarius, Cathorops, and Ariopsis. In the New World three lineages have independently returned to freshwaters. Some New World ariid lineages show tendency to occur mainly in marine waters.