Phylogenetic relationships within the Eurasian catfish family Siluridae (Pisces: Siluriformes), with comments on generic validities and biogeography

Abstract

A numerical cladistic analysis, based on 23 terminal groups and 63 morphological characters, was done to infer phylogenetic relationships within the Eurasian catfish family Siluridae. Nine hundred and forty-five equally most parsimonious trees (134 steps, consistency index 0.634) were found that differ in their resolutions of four polychotomies. Strict consensus of these trees includes ten internal nodes, does not support monophyly of Silurus, Ompok and Kvpfopteru, as usually defined, and offers ambiguous support for monophyly of WauagO. Sihrlrr and Ktyptopterus are each composed of two non-sister group clades, and Ompok is composed of at least two such clades. Heuristic searches constrained by monophyly of Silurus, Ompok or Ktyptopterus yielded trees five or six steps longer than the shortest trees free of constraints. The strict consensus also infers a basal dichotomy that separates the Siluridae into a temperate Eurasian clade with about 20 nominal species and a subtropical/tropical south and southeast Asian clade with about 7.5 nominal species. The distributions of these clades overlap in a relatively narrow region of east Asia. A heuristic search for trees 1 step longer than the shortest trees yielded 253890 trees. A strict consensus of these trees also infers a basal dichotomy between the above-mentioned clades. This analysis revealed four additional putative synapomorphies of the Siluridae, pending further resolution of the family's outgroup relationships.

Osteology and myology of the cephalic region and pectoral girdle of the Chinese catfish Cranoglanis bouderius, with a discussion on the autapomorphies and phylogenetic relationships of the Cranoglanididae (Teleostei: Siluriformes)

“…These cartilages could present different sizes and different shapes in different catfish taxa. For example, they could be well-developed and somewhat rectangular (e.g., erethistids, ariids, cetopsids, claroteids, heteropneustids, plotosids, and clariids), well-developed but with an irregular shape (e.g., sisorids), or significantly long and thin (e.g., nematogenyids, bagrids, amphiliids) (this study; also Takahasi, 1925;Munshi, 1960;Alexander, 1965;Singh, 1967;Singh and Munshi, 1968;Howes, 1983a;Ghiot et al, 1984;Mo, 1991;Bornbusch, 1995;Diogo et al, 1999Diogo and Chardon, 2000a,c). However, only in the Cranoglanididae the cartilages associated with the mandibular barbels are significantly broad, with a somewhat circular shape (see Fig.…”

“…In fact, despite the large number of works concerning catfish anatomy (Regan, 1911;Alexander, 1965;Chardon, 1968;Gosline, 1975;Lundberg, 1975Lundberg, , 1982Howes, 1983aHowes, ,b, 1985Arratia, 1987Arratia, , 1990Arratia, , 1992Mo, 1991;Bornbusch, 1995;Diogo et al, 1999Diogo and Chardon, 2000a,b,c), the only article describing the morphology of cranoglanidids is that of Jayaram (1956), with this description being very incomplete and, very likely, even inaccurate in some points (see Chardon, 1968). The lack of studies concerning the morphology of the cranoglanidids probably explains why, although it is commonly accepted that these fishes should be grouped in a separate family (Cranoglanididae), not even one autapomorphy has been suggested so far to define this family (see Teugels, 1996).…”

Kryptopterus geminus, a new species of silurid catfish (Teleostei: Siluridae) from mainland Southeast Asia

“…Both K. cryptopterus and K. geminus can be distinguished from all other silurids in possessing the following two synapomorphies: a supralabial fold that is anteriorly truncated such that the lower edge extends far posterior to the base of the maxillary barbel and an elongate antorbital process of the lateral ethmoid that is not anteroposteriorly compressed (Bornbusch, 1995). Kryptopterus geminus and K. cryptopterus also do not show any marked sexual dimorphism in the pectoral-fin spine as reported for most other silurid genera (e.g.…”

“…Kryptopterus, as currently understood, is known to be paraphyletic and shown to consist of at least two distinct clades (Bornbusch, 1995). This is reflected in the recent taxonomy of the group, in which the large species with elevated (14-17 vs. 8-13) branchiostegal-ray counts are reassigned to the genus Micronema (e.g.…”

Ompok platyrhynchus, a new silurid catfish (Teleostei: Siluridae) from Borneo

“…Bornbusch (1995) showed that Ompok, as currently understood, is probably paraphyletic. However, given the weak support for the monophyly of his clades, the taxonomy of Ompok is not stable enough to reassign any of the existing species to other genera.…”