Osteological Observations on the Alytid Anura Latonia nigriventer with Comments on Functional Morphology, Biogeography, and Evolutionary History.

The Hula Painted Frog (Latonia nigriventer) is a rare frog species endemic to the Hula Valley, Israel. The species is the sole relict of a clade that was widespread mainly in Europe from the Oligocene until the beginning of the Pleistocene. The osteological characteristics of L. nigriventer are described based on X-ray microtomography scans of extant specimens and Pleistocene bones from the Hula Valley, to elucidate the evolutionary history of Alytidae and more specifically of Latonia. Based on the osteological description of L. nigriventer, we now better understand the differences, between Latonia and its sister taxon Discoglossus. They differ mainly in their cranial structure with the reinforced skull of Latonia having powerful jaws. Latonia nigriventer can achieve great force while closing its jaws, due to increased adductor muscle insertion surfaces as expressed by the presence of an additional paracoronoid process and an enlarged upper margin of the postero-lateral wall of the lower jaw. In addition, a wider pterygoid fossa and higher canthus postero-lateralis of the frontoparietal, compared to that of Discoglossus, also suggest the presence of well-developed adductor muscles. Furthermore, L. nigriventer have particularly strong skulls as expressed by: long articulations between different skull elements, interdigitation in the contact area between the nasals and between nasals and the frontoparietals, and fused frontoparietals. Both males and females L. nigriventer have very robust forelimbs, as indicated by well-developed medial crests of the humerus. Based on limited eastern Mediterranean paleontological data, we can only suspect that the dispersal of Latonia into the Levant from Asia Minor occurred at some point during the Miocene or later. The first appearance of L. nigriventer in the Hula Valley, its current habitat, dates to approximately 780 thousand years ago at the archaeological site of Gesher Benot Ya'aqov. J. Morphol. 277:1131-1145, 2016. © 2016 Wiley Periodicals, Inc.