The fossil record of sabre-tooth characins (Teleostei: Characiformes: Cynodontinae), their phylogenetic relationships and palaeobiogeographical implications

The family Cynodontidae is composed of freshwater fishes inhabiting drainages east the Andes in South America. Its fossil record mostly represented by isolated teeth that are difficult to identify. Here we describe cranial remains extant species Hydrolycus scomberoides as well were identified and cf. Rhaphiodon sediments late Pliocene Ware Formation Guajira Peninsula, west Andes. Novel, phylogenetically informative characters found including number symphysial teeth, plane insertion leading onto dentary, presence accessory posterior dentigerous patches, depressions outline dentary. We performed a phylogenetic analysis combining morphological molecular both extinct specimens, producing well-resolved topology recovers novel sister-group relationship between genera Cynodon, while genus falls base this clade. This contradicts earlier studies recovering sister taxa. position wallacei was be unstable. occurrence H. puzzle could explained different mechanisms, persistent drainage connection across during Pliocene, and/or result severe drying subsequent extinction.