Further evidence for the presence of holoptychiid porolepiforms (Sarcopterygii, Dipnomorpha) from the Frasnian of Colombia

Abstract

The Devonian (Frasnian) of Colombia has provided important information on the taxonomical diversity and palaeobiogeographic relationships of the Late Devonian marginal marine vertebrate faunas of South America (northwestern margin of Gondwana). This fauna is mostly composed of Gondwanan endemics, but includes two taxa also known in Euramerica: the antiarchan placoderm Asterolepis and the porolepiform sarcopterygian Holoptychius. The occurrence of holoptychiid porolepiforms in Colombia was previously suggested based solely on the presence of scales attributed to Holoptychius, although with caution. Here, we describe further holoptychiid remains that include a large isolated tooth with dendrodont microstructure, typical of porolepiforms, and additional Holoptychius scales. These new findings increase the record of holoptychiid porolepiform occurrences in Gondwana and suggest that dispersion of fish faunas between Euramerica and Gondwana by the beginning of the Late Devonian was possible through South America.