A phylogenetic study of the neotropical catfish family Cetopsidae (Osteichthyes, Ostariophysi, Siluriformes), with a new classification

Abstract

A hypothesis on the phylogenetic relationships of the neotropical catfish family Cetopsidae is proposed on the basis of the parsimony analysis of 127 morphological characters and most of the species currently recognized. The family and its two recognized subfamilies, the Cetopsinae and Helogeninae, are corroborated as monophyletic, in agreement with recent studies. Previously proposed classifications of the Cetopsinae, however, were found to be poorly representative of the phylogenetic relationships within the subfamily. Major generic rearrangements are implemented in order that the classification of the Cetopsinae reflects the phylogenetic hypothesis. Pseudocetopsis Bleeker (1862) was found to be polyphyletic and to include several disjunct lineages. One of these lineages, recently named as the genus Cetopsidium Vari, Ferraris, and de Pinna (2005), is the sister group to the rest of the Cetopsinae. Denticetopsis Ferraris (1996) is the next sister group to the remainder of the Cetopsinae. The remaining species of the Cetopsinae belong to one of two sister genera, Paracetopsis Bleeker (1862) and Cetopsis Spix and Agassiz (1829). The latter genus includes species formerly assigned to Hemicetopsis Bleeker (1862), Bathycetopsis Lundberg and Rapp Py-Daniel (1994) and Pseudocetopsis Bleeker (1862). Continued recognition of Hemicetopsis and Bathycetopsis would have required the creation of several additional new genera for various species previously in Pseudocetopsis that form a series of sister groups to a clade composed of Cetopsis oliveirai (Lundberg and Rapp Py-Daniel, 1994), C. coecutiens (Lichtenstein, 1819) and C. candiru (Spix and Agassiz, 1829). Cetopsis oliveirai is a highly paedomorphic species that displays surprising similarities with conditions in juvenile specimens of C. coecutiens , a species that attains a large body size. Such similarities are not evident in adult specimens of the latter species. A new classification is proposed, within which the subfamily Cetopsinae consists of three tribes, the Cetopsidiini, the Cetopsini and the Denticetopsini. The results of the study form the basis for a discussion of the phylogenetic position of the family within the Siluriformes, the phylogenetic biogeography of the Cetopsidae, paedomorphosis and gigantism in the family, and the effect of different semaphoronts on the intrafamilial phylogeny. Journal compilation

Phylogenetic relationships of the South American Doradoidea (Ostariophysi: Siluriformes)

“…20; Alexander, 1965;Lundberg, 1970;de Pinna et al, 2007). However, in all other catfishes examined, the adductor mandibulae originates on the lateral border of the cranium (sphenotic and pterotic), leaving the dorsalmost bones exposed, especially the parietalsupraoccipital and frontals (Figs.…”

Description of a new catfish genus (Siluriformes, Loricariidae) from the Tocantins River basin in central Brazil, with comments on the historical zoogeography of the new taxon

“…material 1 for all taxa). Diplomystes mesembrinus (Ringuelet, 1982) was used as the outgroup to root all phylogenies (Arratia 1987; de Pinna 1993, 1998; Grande 1987; Grande and de Pinna 1998; Mo 1991; Sullivan et al 2006). Samples of Corydoras imitator Nijssen & Isbrücker, 1983, Corydoras oiapoquensis Nijssen, 1972, Hoplosternum littorale (Hancock, 1828), Callichthys callichthys (Linnaeus, 1758), Astroblepus spp.…”

New species of Cetopsidium (Siluriformes: Cetopsidae: Cetopsinae) from the upper rio Branco system in Guyana

“…Such elaborations of these fins are characteristic of mature males of other species of Cetopsidium with the exception of C. ferreirai and occur in all adult males of all genera in the Cetopsinae other than for Denticetopsis Ferraris, 1996(Vari et al, 2005. The male of Cetopsidium soniae has the anal-fin margin slightly convex rather than straight as in the female, another sexually dimorphic feature shared with mature males of the majority of species within the Cetopsinae with the exception of the members of Denticetopsis and some species of Cetopsis Spix & Agassiz, 1829 (Vari et al, 2005;de Pinna et al, 2007).…”

“…All of these features are present in C. soniae. Only one of these conditions, a lateral line that fails to extend past the vertical through the posterior terminus of the anal-fin base, was determined to be synapomorphic for the members of the genus under the phylogenetic hypothesis of relationships within the Cetopsidae proposed by de Pinna et al (2007). The remaining external features that serve in combination to diagnose Cetopsidium (the presence of an ossified spinelet and possession of pectoral-and dorsal-fin spines) are symplesiomorphic within the Cetopsidae according to the results of that analysis.…”

“…The remaining external features that serve in combination to diagnose Cetopsidium (the presence of an ossified spinelet and possession of pectoral-and dorsal-fin spines) are symplesiomorphic within the Cetopsidae according to the results of that analysis. The additional synapomorphies identified by de Pinna et al (2007) for Cetopsidium are internal features involving the first and third hypobranchials and the radials anterior to the anal-fin pterygiophores. The limited available sample of C. soniae prevented confirmation of these osteological features in the species.…”