A phylogenetic analysis of the Asian catfish families Sisoridae, Akysidae, and Amblycipitidae, with a hypothesis on the relationships of the Neotropical Aspredinidae (Teleostei, Ostariophysi)

A Phylogenetic Analysis of the Asian Catfish Families Sisoridae, Akysidae, and Amblycipitidae, with a Hypothesis on the Relationships of the Neotropical Aspredinidae (Teleostei, Ostariophysi) Mario C. C. de Pinna Abstract A cladistic analysis based on 1 1 2 morphological characters was conducted for the Asiatic catfish families Sisoridae, Akysidae, and Amblycipitidae and the Neotropical family Aspredi-nidae. Sisoridae, Akysidae, and Amblycipitidae were divided into nearly all their currently recognized genera for the analysis, but Aspredinidae was treated as a single taxon, for a total of 20 terminal taxa. The single, fully resolved most parsimonious cladogram requires numerous modifications of the previous suprageneric classification of these fishes. The Sisoridae of pre-vious authors was found to be a paraphyletic assemblage because a subunit of it is more closely related to the Aspredinidae than to remaining taxa so far allocated in Sisoridae. Therefore, the current Sisoridae is split into the monophyletic Sisoridae (sensu stricto) and Erethistidae, with Erethistidae hypothesized as the sister group to Aspredinidae. Akysidae (including Parakysis) is demonstrated to form a monophyletic group and to be the sister group to the clade Sisoridae {sensu stricto) + Erethistidae + Aspredinidae. Within Akysidae, relationships hypothesized are (Akysis (Parakysis (Breitensteinia, Acrochordonichthys))). Amblycipitidae is also shown to be monophyletic and is the sister group to all other families treated in the analysis. Sisoridae is composed of two major lineages, one represented by (Bagarius (Sisor (Nangra, Gagata))) and the other by {Glyptothorax (Pseudecheneis, "glyptostemoids")). Relationships among the genera of Erethistidae are hypothesized as (Conta ((Laguvia, Pseudolaguvia) (Erethistoides (Erethistes, Hard)))). On the basis of the hypothesized relationships, a new classification of the whole group, named superfamily Sisoroidea, is proposed, from the level of family down to tribe and subtribe in some cases. Formal diagnoses are provided for all suprageneric clades proposed, with synon-ymies added for all named taxa. Evidence supporting the monophyly of some genera is also offered, along with a discussion of the possible paraphyly of some others, such as Akysis and Glyptothorax. The evolution of two functional complexes, namely the stridulatory mechanism and the adhesive apparatus, is interpreted in light of the hypothesized relationships. Events of minia-turization and gigantism in Erethistidae and Sisoridae, respectively, are also discussed and compared with similar cases in other ostariophysans. The placement of the Neotropical As-predinidae within an otherwise exclusively Asian clade indicates a trans-Pacific biogeographic component. The implications of this hypothesis are discussed. Resumo Uma analise cladistica baseada em 1 1 2 caracteres morfologicos e apresentada para as familias asiaticas Sisoridae, Akysidae, Amblycipitidae e para a familia Neotropical Aspredinidae. Os FIELDIANA: ZOOLOGY, N.S., NO. 84, JULY 31, 1996, PP. 1-83