DOI: 10.3897/vz.76.e180973

Authors: Oleg V. Brandler, Andrey R. Tukhbatullin, Svetlana Y. Kapustina, Sergey N. Matveevsky, Fatimat A. Tembotova, Andrey Y. Puzachenko

Abstract: Abstract The systematics of blind mole rats (Spalacinae), a group of highly specialized subterranean rodents, remain a subject of debate. Within the genus Spalax, the greater blind mole rat (Spalax microphthalmus) is distinguished by its unique diploid chromosome number (2n = 60 versus 2n = 62 in others) and the most extensive geographic range. However, its intraspecific variation has been insufficiently studied. Previous finding of specimens with 2n = 62 in the North Caucasus were attributed to chromosomal polymorphism within S. microphthalmus. In this study, we conducted a comprehensive analysis of morphometric, morphological, molecular, and chromosomal variation across the entire range of S. microphthalmus, integrated with a comparative analysis of the genus Spalax. Our results demonstrate that the North Caucasian populations (2n = 62) exhibit consistent species-level differences in molecular genetics (from 8% to 12% divergence in cyt b), karyotype, and cranial morphology, distinguishing them from S. microphthalmus and all other congeners. This lineage also possesses a unique combination of morphological traits, including features that bring it closer to the hypothetical common ancestor of all modern Spalax species. Based on this integrative evidence, we describe this lineage as a new species: Spalax lyapunovae sp. nov., increasing the number of extant Spalax species to nine. This newly recognized species, endemic to the central North Caucasus, requires further ecological and distributional studies. Given its presumably limited range, an urgent assessment of its conservation status is warranted.

HTML

XML

PDF

DOI: 10.3897/vz.75.e167908

Authors: Irina V. Kulikova, Philip Lavretsky, Kevin G. McCracken, Yury N. Zhuravlev, Irina L. Miroshnichenko, Andrew B. Correll, Jeffrey L. Peters

Abstract: Eurasian wigeon (Mareca penelope) and American wigeon (Mareca americana) are sister species with diagnosable differences mostly in male plumage. They breed in the Palearctic and Nearctic, respectively, but due to transoceanic migrations come in contact in North America, Western Europe, and north-eastern Asia, where they occasionally hybridize. To estimate genomic divergence and study their population structure we sequenced mitochondrial (mt) DNA control region and obtained 3092 autosomal and 189 Z chromosome loci from double-digest restriction associated DNA sequencing (ddRAD-seq). Consistent with previous work with few nuclear loci, we observed discordant patterns between mtDNA and nuclear DNA divergence. Deeply divergent species-specific mtDNA haplogroups contrasted with low autosomal differentiation and moderate Z-sex chromosome divergence. Meanwhile, Z-linked differentiation (ФST = 0.192) between taxa was five times higher than differentiation of autosomal loci (ФST = 0.0386), with four fixed and eight nearly fixed differences in SNPs discovered in three and six Z-linked outlier loci, respectively. No species-specific SNP variants were found among 83 autosomal outlier loci. This elevated Z-chromosome differentiation is most likely the result of selection that has been important in speciation. The lack of population genetic structure within Eurasian wigeon and American wigeon supports the common notion that migratory waterfowl have high dispersal ability that contributes to strong genetic connectivity between geographic populations.

HTML

XML

PDF

DOI: 10.3897/vz.75.e153115

Authors: Anna A. Bannikova, Paulina D. Jenkins, Vladimir S. Lebedev, Svetlana V. Pavlova, Vasily D. Yakushov, Alexandra A. Raspopova, Yongke Zhu, Yun Fang, Yue-Hua Sun, Boris I. Sheftel

Abstract: Abstract The taxonomy of the stripe-backed shrew complex (Sorex cylindricauda species group), distributed in mountains of western China, appears challenging due to remarkable variation in morphological traits and relatively recent times of diversification. According to classical points of view only two or three species of the stripe-backed shrews can be distinguished. However, previous molecular reconstructions revealed at least 14 genetic lineages including a number of undescribed cryptic species. In the current study we revise the taxonomic status of large-sized stripe-backed shrews occurring in high mountain areas in south Gansu, north-western Sichuan and western Qinghai that were previously treated as S. aff. cylindricauda or S. sinalis. The available molecular data place them in a separate species-level lineage of the stripe-backed shrew complex. Our morphological analysis indicate that shrews of this lineage are distinct from the two other large-sized Chinese species, S. cylindricauda and S. sinalis, based on both cranial and external traits. Therefore, we here describe it as a species new to science, the karyotype of which is characterized by 2n = 26 with an additional B chromosome and NFa = 44. Our molecular phylogenetic analysis demonstrates multiple instances of mitonuclear discordance among lineages within the S. cylindricauda complex, which is likely a result of mtDNA introgression, thus highlighting the important role of reticulation events in the evolution of the group.

HTML

XML

PDF