A new lungfish (Dipnoi) from the Late Triassic of South America

AGNOLIN, F.L., BOGAN, S., BRISSON EGLI, F., NOVAS, F.E., ISASI, M.P., MARSICANO, C., ZAVATTIERI, A.M. & MANCUSO, A.

JOURNAL OF VERTEBRATE PALEONTOLOGY

SOC VERTEBRATE PALEONTOLOGY

Lugar: Lawrence; Año: 2016 p. 1 - 6

0272-4634

Lungfishes belong to the sarcopterygian clade Dipnoi. Living forms are represented by three genera distributed among South America, Africa, and Australia. The oldest fossil record of lungfishes is Devonian (see Long, 2010), but they become notably abundant in post-Paleozoic deposits (Martin, 1982; Schultze, 2004). The oldest South American records of fossil lungfishes come from Permian beds in Brazil (Cox and Hutchinson, 1991; Toledo and Bertini, 2005; Toledo, 2006). These specimens consist of isolated tooth plates assigned to Ceratodontidae and Gnathorizidae. Triassic finds are restricted to a single and incomplete tooth plate from the Santa Marıa Formation (Carnian) of Brazil(Richter and Toledo, 2008). The specimen was referred to Ptychoceratodus, being probably related to the European form P. phillipsi. Because of the paucity of the record, Triassic South American lungfishes almost completely lack mention in most paleobiogeographical analyses of early Mesozoic dipnoan distribution and radiation. In Jurassic beds, the record is restricted to isolated plates belonging to Ceratodus and ?Arganodus? from isolated localities in Brazil and Uruguay (Soto and Perea, 2010). In contrast, the Cretaceous and Paleogene lungfish record is especially abundant and diverse (Fernandez et al., 1973; Pascual and Bondesio, 1976; Toledo and Bertini, 2005; Apesteguıa et al., 2007; Cione et al., 2007, 2010; Agnolin, 2010; Cione and Gouiric, 2012; Alves et al., 2013). Here, we expand the record of South American dipnoans, describing a tooth plate and associated jaw bone from the Late Triassic (Carnian) Potrerillos Formation at the Agua de las Avispas fossiliferous locality, Mendoza Province, Argentina (Fig. 1). This is a well-known fossiliferous spot that has yielded a large number of plant and arthropod specimens, as well as fragmentaryactinopterygian material (Zavattieri and Pramparo, 2006; Morel et al., 2010; Gallego et al., 2011; Lara et al., 2012). The specimen here described is assigned to a new species of the widespread genus Ptychoceratodus and is the most complete Triassic dipnoan from South America.