Morphometrics and genetics highlight the complex history of Eastern Mediterranean spiny mice

Abstract

Spiny mice of the Acomys cahirinus group display a complex geographical structure in the Eastern Mediterranean area, as shown by previous genetic and chromosomal studies. To better elucidate the evolutionary relationships between insular populations from Crete and Cyprus and continental populations from North Africa and Cilicia in Turkey, genetic and morphometric variations were investigated, based on mitochondrial D-loop sequences, and the size and shape of the first upper molar. The Cypriot and the Cilician populations show idiosyncratic divergence in molar size and shape, while Cretan populations present a geographical structure with at least three differentiated subpopulations, as shown by congruent distributions of haplogroups, Robertsonian fusions and morphometric variation. A complex history of multiple introductions is probably responsible for this structure, and insular isolation coupled with habitat shift should have further promoted a pronounced and rapid morphological evolution in molar size and shape on Crete and Cyprus.

4 Zooarchaeological research in Greece from 2010 to date: A review

“…Recently, however, the animals themselves have become the subject of isotopic investigation, with research questions pertaining to animal diet as a means to examine pastoral territories and to animal mobility as a proxy for human mobility (Nitsch et al 2017;Vaiglova et al 2018;Isaakidou et al 2019;Alagich et al 2021). Similar topics are explored with genetic analysis of micromammal bones (Meiri et al 2017;Frantz et al 2019;Renaud et al 2020). Currently, several major research projects use isotopic and genetic tools to explore human-animal relations in the region of the Mediterranean and Europe more broadly, which include zooarchaeological material from Greece (for example NEOMATRIX, ZOOCRETE, AGRICURBlinks provided at the end of this paper).…”

Deep learning for species identification of modern and fossil rodent molars

“…This sampling was completed by specimens from Crete (61), Cyprus (6) and Turkey (17). The context of isolation on the islands of Crete and Cyprus, and to some extent in the restricted patch where Acomys is found in Turkey, drove morphological differences in tooth size and shape (Renaud et al 2020).…”

“…Because the first point was only defined on the basis of a maximum of curvature at the anterior-most part of the UM1, some slight offset might occur between specimens. The first point was therefore considered as a semi-landmark allowed to slide between the last and second points (Renaud et al 2020). To compare the fossil UM1 to the modern dataset, all molars were superimposed in a same procedure.…”

“…They thus provide a case study of close but recognizable morphologies to test the relative performance between GMM and deep learning approaches. Furthermore, previous studies on these species (Renaud et al 2020;Renaud et al 2017;Renaud and Michaux 2003;Renaud et al 2015) made available a high number of pictures to feed the deep learning approach with well-identified modern specimens. The test focused on the first upper molar (UM1) which bears most of the phylogenetically relevant characters in murine rodents (J.…”

“…Achieving this diversity in the reference dataset should be done first, by including as much intraspecific variation as possible. For instance, in our case study, all the three species display important geographic variation, especially on islands (Ledevin et al 2016;Renaud et al 2020;Renaud and Michaux 2007). If the specimens to be reclassified come from insular environment, such as those from the Tuda sequence, it is advisable that the range of morphological variation encountered on different islands is included in the reference dataset.…”