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Tapinocephalid dinocephalian (Therapsida) from Permian of Brazil



Ben Creisler
bcreisler@gmail.com


A new online paper:

A.D.S. Boos, C.F. Kammerer, C.L. Schultz & V.D. Paes Neto (2015)
A tapinocephalid dinocephalian (Synapsida, Therapsida) from the Rio do
Rasto Formation (Paraná Basin, Brazil): taxonomic, ontogenetic and
biostratigraphic considerations.
Journal of South American Earth Sciences (advance online publication)
doi:10.1016/j.jsames.2015.09.003
http://www.sciencedirect.com/science/article/pii/S0895981115300559



Highlights

The use of local fauna to the tetrapod-bearing sites of the Rio do
Rasto Fm is ended.
Serra do Cadeado railway sites bear Guadalupian/Lopingian horizons.
The most complete tapinocephalid of South America is described for the
first time.
It is a juvenile specimen and tapinocephalid ontogeny is partially explored.

Abstract

Permian tetrapod fossils have been recovered from the Rio do Rasto
Formation of Brazil since the 1970s. Previous studies of this fauna
indicated strong affinities with the Guadalupian-Lopingian vertebrates
of South Africa and Eastern Europe, suggesting biostratigraphic
correlations between these areas. Here, a new dinocephalian specimen
from the Rio do Rasto Formation in the Serra do Cadeado area (Paraná
State, Brazil) is described based on fragmentary skull remains and an
associated left lower jaw ramus. Despite the fragmentary nature of
these remains, they represent the most complete tapinocephalid
specimen known from South America. Comparison with other
tapinocephalids indicates that the material described herein
represents a juvenile or sub-adult specimen. Although it is not
possible to identify this material to the genus level, it most closely
resembles the ‘moschopines’ Moschops and Moschognathus from the
Tapinocephalus Assemblage Zone of South Africa. As dinocephalians are
known to be restricted to the Guadalupian, they are one of the best
tetrapod biostratigraphic markers for the Rio do Rasto Formation,
indicating that at least some of the strata in the areas where they
occur [Serra do Cadeado (Paraná State), Fagundes farm and Boqueirão
farm (Rio Grande do Sul State)] are Guadalupian. Vertebrate fossils
from Rio do Rasto Formation occur in disperse, isolated and
discontinuous outcrops, so that they have been grouped in ‘local
faunas’. However, most of the specimens lack precise stratigraphic
provenance data and even occurring in locations near each other they
are not necessarily contemporary. Thus, until a more robust
stratigraphic framework is developed, we suggest discontinuing use of
‘local faunas’ to this stratigraphic unit.