Lacustrine coelacanths from the Permian of NE Brazil and their affinities with Palaeozoic and Mesozoic actinistians

RICHTER, MARTHA; CISNEROS, JUAN; ANGIELCZYK, KEN; FROBISCH, JORG; KAMMERER, CHRISTIAN; MARSICANO, CLAUDIA; SMITH, ROGER

Simposio; 13th International symposium on Early and Lower Vertebrates:; 2015

The Pedra de Fogo Formation of the Parnaíba Basin in NE Brazil comprises vast lakedeposits located in the tropics of Pangaea during the Permian. Over the past four years ourteam has collected hundreds of vertebrate, invertebrate and plant fossils from over 200localities in the areas surrounding the town of Pastos Bons and the city of Teresina.Ichthyofossils are ubiquitous, comprising lower actinopterygians, dipnoans andchondrichthyans, together with various temnospondyls and a possible reptile. In addition, thearticulated remains of four coelacanth fishes were recently recovered from four localities inthe states of Piauí and Maranhão. Two of the fossils represent postcranial remains ofindividuals estimated to have been at least one metre in total length; the largest measures 22mm and displays strong abdominal ribs; the second is a well-preserved yet incomplete tailshowing dermal scales ornamented with longitudinal ridges. Two small 3-dimensionallypreserved specimens were found still embedded in silty mudstones. They both havearticulated cranial and post-cranial elements and are smaller than the young of the extantcoelacanth Latimeria. The two, more complete specimens have been micro-CT scanned andreconstructed utilizing virtual imaging software. The dermal scale ornamentation in both ofthese specimens display closely-packed, elongated ridges like those observed in Whiteianielseni from the Early Triassic of Madagascar. A comparative description of the fourspecimens is presented with a discussion of their possible interrelationships with otherPalaeozoic and Mesozoic actinistians.