Mitogenomic Analysis of Glirids (Gliridae) and Squirrels (Sciuridae) From Türkiye: Evolutionary and Taxonomic Implications Within the Suborder Sciuromorpha.

Gliridae and Sciuridae, the most impressive mammalian radiations within the suborder Sciuromorpha, encompass a total of 327 extant species. This study aimed to: (i) characterize the mitogenomes of three sciurid (Spermophilus citellus, Spermophilus taurensis, and Spermophilus xanthoprymnus) and three glirid (Glis glis, Dryomys nitedula, and Dryomys laniger) species from Türkiye; (ii) elucidate the phylogeographic relationships within D. laniger and D. nitedula using both mitogenomes and mitochondrial cytochrome b (CYTB) sequences; and (iii) reconstruct the phylogenetic relationships among extant members of the suborder Sciuromorpha. Sixteen new mitogenomes were sequenced from Turkish samples, containing 37 genes (2 ribosomal RNAs, 13 protein-coding genes, 22 transfer RNAs), exhibiting similarity to those of other Gliridae and Sciuridae species. Based on mitogenomic data, Bayesian Inference and Maximum Likelihood phylogenetic analyses revealed two major phylogroups corresponding to the two families, Gliridae and Sciuridae, which were both monophyletic. Analyses of mitogenomic and CYTB sequences revealed at least two major lineages (i: Anatolia and ii: Lesser Caucasus and Alborz) of D. nitedula in the Anatolian region of Türkiye. The mitochondrial CYTB data indicated that D. laniger exhibited at least two major lineages (Eastern and Western), whereas D. nitedula comprised multiple lineages and sublineages. The mean genetic distance between the two mitogenomic lineages of D. nitedula was 7.69%. Based on the CYTB data, the mean genetic distance between the Eastern and Western lineages of D. laniger was 7%, whereas the mean genetic distances among the lineages of D. nitedula ranged from 6% to 13%. Major lineages of both D. laniger and D. nitedula might be considered distinct species throughout the species' range. This study demonstrates that complete mitogenomes for reconstructing the Gliridae phylogeny provides important information for revealing phylogenetic and phylogeographic relationships.