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Vol. 54, 2015
Variation in the ilium of central European water frogs Pelophylax (Amphibia, Ranidae) and its implications for species-level identification of fragmentary anuran fossils
Hugues-Alexandre Blain1,2*, Iván Lózano-Fernández1,2, and Gottfried Böhme3
1IPHES,
Institut Català de Paleoecologia Humana i Evolució Social, c/ Marcellí
Domingo s/n (Edifici W3), Campus Sescelades, 43007 Tarragona, Spain
2Area de Prehistoria, Universitat Rovira i Virgili (URV), Avinguda de Catalunya 35, 43002 Tarragona, Spain
3Museum
für Naturkunde, Leibniz-Institut für Evolutions- und
Biodiversitätsforschung an der Humboldt-Universität zu Berlin,
Invalidenstrasse 43, 10115 Berlin, Germany
Abstract
Background: A total of 454 ilia of modern green frogs from the former German Democratic Republic have been studied: 168 for P. lessonae (86 of males and 82 of females), 118 for P. ridibundus (44 of males and 74 of females) and 168 for P. kl. P. esculentus
(86 of males and 82 of females). The origin, sex, population structure
and phenotype are known for each of the studied specimens. Eight
variables have been taken (one angle and seven measurements), mainly on
the distal part of the element in order to be able to apply them to
fragmentary fossil ilia. Interspecific variations, sexual dimorphism
and population structure have been investigated. Results suggest that
the secure determination of a single fossil ilium at species level is
quite impossible, but that at population level, it may be possible to
distinguish between a ‘pure’ species or a ‘pure’ species plus its
cohabiting hybrid form, as some minor differences have been evidenced
in particular in the angle of the tuber superior
in relation to iliac's main axis (character 2) and the width of the
pars ascendens (character 8); two parameters significantly non
size-dependent. No sexual dimorphism has been detected, except for P. lessonae.
Results: The genetic analyses of the
mitochondrial 16S rRNA, cytochrome oxidase subunit I (COI), and control
region (CR) of specimens from various localities showed that there was
no genetic differentiation between the populations inside and outside
of the Persian Gulf.
Conclusions: We
propose here a new biometrical method in order to differentiate between
the fossil ilia of central European water frogs (genus Pelophylax) at
population level.
Key words:
Ilium; Pelophylax; Osteology; Biometry; Klepton; Central Europe.
*Correspondence: E-mail: hablain@iphes.cat
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