Phylogeny, origin and biogeography of catfishes: support for a Pangean origin of 'modern teleosts' and reexamination of some Mesozoic Pangean connections between the Gondwanan and Laurasian supercontinents

The wide geographical distribution of the mainly freshwater catfishes has long intrigued the scientific community. This work provides a new insight into the phylogeny and the puzzling bio-geographical distribution of catfishes. The important implications for teleost biogeography and plate tectonics are discussed. The results of the author's cladistic study on catfish higher level phylogeny, together with a revision of the data available concerning different fields such as palaeobiogeography, phylogeny. ecology and molecular biology, as well as the growing evidence supporting the existence of some remaining Pangean connections between Gondwana and Laurasia extending into the Early Cretaceous, strongly support a rather complex biogeographic scenario with multiple pre-drift and post-drift continental dispersions, vicariances, and, possibly, some marine migrations. According to this scenario: 1) catfishes originated in the South American region at a moment when there were still some remaining Pangean connections between Gondwana and Laurasia; 2) after this, there was a relatively rapid pre-drift continental dispersion of several, but not all, main groups of Siluriformes from the South-American region to Africa and other Gondwanan areas, with some of those groups succeeding in radiating ulteriorly via the remaining continental Pangean connections between Gondwana and Laurasia to this latter super-continent; 3) the final separation between Laurasia and Gondwana, and posteriorly between the regions constituting each of these super-continents, contributed to important vicariant events; 4) this scenario was still further complicated by numerous events such as the collision of India with Asia, the re-establishment of certain land connections between previously separated continents (e.g., between the Americas), and eventually also by some marine migrations, thus explaining the highly complex biogeographical distribution of the Siluriformes. In sustaining such a scenario, this work thus supports that, contrary to what is often accepted, some groups of 'modern teleosts' did have a Pangean origin.