ORIGINAL PAPER
A new pelobatoid frog from the lower Eocene of southern China
Yuan Wang
1
&
ZbyněkRoček
1,2
&
Liping Dong
1
Received: 10 May 2017 /Revised: 26 June 2017 / Accepted: 31 August 2017 / Published online: 6 October 2017
#
Senckenberg Gesellschaft für Naturforschung and Springer-Verlag GmbH Germany 2017
Abstract A new frog with pelobatoid affinities is described
from the lower Eocene of southern China based on 11 indi-
viduals at different developmental stages. Comparative ana-
lysis reveals that this anuran shares osteological characters
with the rather diverse family Megophryidae. In particular,
intervertebral discs are present between the anterior vertebral
centra and the lamella alaris of the squamosal is widely sepa-
rated from the maxilla, which lacks a zygomaticomaxillar
process. The new frog also shares features with the genus
Pelodytes and especially with its most primitive extant spe-
cies, P. caucasicus. Particularly given that Pelodytidae and
Megophryidae are grouped in the Pelobatoidea, and that the
new fossil frog existed almost 50 Ma ago, these comparisons
suggest that the new frog represents a Paleogene member of
the Pelobatoidea. Phylogenetic analysis supports this conclu-
sion, but relationships within the superfamily Pelobatoidea
remain unstable across different analyses, as do the positions
of fossil frogs of similar geological age in Mongolia (Prospea)
and USA (Aerugoamnis). Nevertheless, this new discovery
represents the first record of a Paleogene frog from China as
well as the first fossil anuran from South China, filling the
large gap between Chinese Cretaceous and Neogene anurans.
The new frog also opens an important window on the early
evolutionary history of the Pelobatoidea, which presumably
originated in East Asia.
Keywords Pelobatoidea
.
Pelodytidae
.
Megophryidae
.
Anura
.
Eocene
.
China
Introduction
A short time ago, it was still widely accepted that the family
Pelobatidae included not only the European genus Pelobates
and the extinct Eopelobates, but also the North American
Scaphiopus and Spea in addition to the so-called Oriental
pelobatids, represented principally by Megophrys, Lepto-
brachium and Scutiger (e.g. Duellman and Trueb 1985). This
view was based partly on distinctive shared external features
such as a vertically oriented pupil, but even more on skeletal
characters including the presence of eight presacral vertebrae
with procoelous centra and imbricated neural arches, and great-
ly expanded sacral diapophyses. Only recently has a consensus
emerged, on the basis of molecular studies, that Megophryidae
and Scaphiopodidae should be considered separate families
from Pelobatidae (Frost et al. 2006). The three families, togeth-
er with the closely related Pelodytidae, constitute the monophy-
letic group Pelobatoidea (Ford and Cannatella 1993; García-
París et al. 2003; Pyron and Wiens 2011).
The unquestionable earliest fossil record of the Pelobatoidea
is Prospea from the latest Paleocene of Mongolia (Chen et al.
2016). The Paleogene seems to have been a time of diversifi-
cation for the Pelobatoidea, as can be judged from the various
taxa known from the Eocene and Oligocene. These include
Aerugoamnis (Henrici et al. 2013)andcf.Scaphiopus (early
Eocene) (Henrici 2000), Miopelodytes (Taylor 1941)and
This article is registered in Zoobank under:
urn:lsid:zoobank.org:pub:6E5956C0-6897-444F-B699-
EA32C6B7D81E
* ZbyněkRoček
Rocek@gli.cas.cz
1
Key Laboratory of Vertebrate Evolution and Human Origins,
Chinese Academy of Sciences, Institute of Vertebrate Paleontology
and Paleoanthropology, CAS, 142 Xi-Zhi-Men-Wai St.,
Beijing 100044, China
2
Laboratory of Palaeobiology, Institute of Geology, Czech Academy
of Sciences, Rozvojová 135, 165 00 Prague, Czech Republic
Palaeobio Palaeoenv (2018) 98:225–242
DOI 10.1007/s12549-017-0304-1
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