Sequence Variation and Molecular Evolution of Hormone-Sensitive Lipase Genes in Species of Bovidae

The partial sequences of exon Ⅰ of hormone-sensitive lipase （HSL） genes in yak （Bos grunniens）, cattle （Bos taurus）, zebu （Bos indicus）, and buffalo （Bubalus bubalis） were analyzed. Comparisons of these sequences and the deduced amino acid sequences with the homologous HSL gene and protein sequences in other mammalian species including pig （Sus scrofa）, human （Homo sapiens）, mouse （Mus musculus）, and rat （Rattus sp.） retrieved from the GenBank were carried out and finally a phylogenetic tree was constructed using the partial DNA sequences of the HSL genes in all species. The results showed that the homologies of the partial exon Ⅰ sequences of the HSL genes between yak and cattle, zebu, buffalo, pig, human, mouse, and rat were as high as 99.8%, 99.6%, 97.4%, 90.6%, 88.4%, 83.5%, and 82.3%, respectively. This was accompanied by highly homologous amino acid sequences of the HSLs： 100%, 100%, 98.2%, 94.0%, 92.2%, 89.8%, and 89.8% identity, respectively. There are more transitions, less transversions, and no insertion or deletion in variable nucleotides of the HSL genes between the yak and other species. The majority of the variable mutations was synonymous and was found most frequently at the third codon, followed by the first and second codons, a finding that was in accordance with the neutralism hypothesis for molecular evolution. In the phylogenetic tree, the cattle and zebu were clustered together first, followed by the yak, buffalo, pig, human, mouse, and rat. This was in agreement with taxonomy suggesting that the partial sequences of exon Ⅰ of the HSL genes were useful in constructing the phylogenetic tree of mammalian species. Among the four species of Bovidae, genetic differentiation in the HSL genes between yak and buffalo is equivalent to that between buffalo and cattle and between buffalo and zebu. Furthermore, the genetic distances in the HSL genes are much smaller between yak, cattle, and zebu than those between each of the three species and the buffalo. Therefore, it is reasonable to consider yak as an independent species of the genus Bos.

The Late Miocene‘ovibovin’bovids in Eurasia

During the Late Miocene,numerous medium to large-sized herbivores,that resemble the living Ovibos in skeletal morphology,dispersed throughout the Holarctic realm and comprised eleven genera:Lantiantragus,Shaanxispira,Tsaidamotherium,Criotherium,Mesembriacerus,Hezhengia,Urmiatherium,Parurmiatherium,Plesiaddax,Sinotragus,and Prosinotragus.These genera are primarily found in eastern Asia,in which nine genera are found in northern China,as well as in countries in eastern Europe and western Asia.They are distinguished by unique characteristics,including a perpendicular braincase,specialized horn cores,and a robust basioccipital.Previous studies have often classified these‘ovibovin’bovids as part of the conventional subfamily/tribe Ovibovinae/Ovibovini,along with extant Ovibos.Nevertheless,an increasing number of studies do not support the monophyly of the subfamily/tribe Ovibovinae/Ovibovini,nor is a close relationship likely between these Late Miocene‘ovibovin’bovids and extant Ovibos.Among the eleven genera of‘ovibovin’bovids,Plesiaddax,Hezhengia,and Urmiatherium are often considered to have a very close relationship and conventionally form the tribe Urmiatheriini.However,previous phylogenetic analyses do not support the monophyly of Urmiatheriini.This paper presents a summary of the transmutation of the terms Ovibovidae/Ovibovinae/Ovibovini/Ovibovina,the temporal and spatial distribution of the Late Miocene‘ovibovin’bovids in Eurasia,the principal characteristics of these taxa,and the previous phylogenetic analyses.

New species of Tsaidamotherium(Bovidae,Artiodactyla) from China sheds new light on the skull morphology and systematics of the genus

A new species of Tsaidamotherium(Bovidae,Artiodactyla),T.brevirostrum,described here represents only the second discovery of the genus.Tsaidamotherium is a mid-sized late Miocene bovid with an odd-looking plate-like horn-core apparatus so far known only from northwestern China.The holotype of T.brevirostrum is a cranial part of skull from the Liushu Formation(late Miocene)of the Linxia Basin.The new species differs from the type species,T.bohlini,mainly in horn-core morphology,having the frontal horn-cores proper much smaller and less distinctly separated from the plate-shaped posterior portion.Furthermore,the new species has smaller frontal sinuses,but a thicker layer of compact bone beneath the horn-core apparatus as seen in frontal section.A complete skull with a smaller horn-core apparatus is considered to represent a female individual of T.brevirostrum.The facial part of the skull,which is first known for this genus,is very short and high,with a high nasal cavity,strongly retracted nasals,and shortened premaxillae and premolar rows.All this probably suggests that the animal with an enlarged nasal cavity,like the modern Saiga and Budorcas,may have had a special adaptation to the high plateau environment.

Do methods for predicting paleohabitats apply for mountain and insular fossil bovids?

A variety of methods have been developed to use bovid postcranial elements in the functional morphology approach to paleohabitat prediction.This study represents a first attempt at testing morphometric methods based on astragalus and phalanges on extant mountain-dwelling bovids and insular fossil bovids from Sardinia assigned to the so-called‘Nesogoral group’,already regarded as close to the Caprini tribe.We intended to answer the questions whether a classic four-habitats model could be successfully applied to extant mountain-dwelling bovids,and whether results obtained could support the hypothesis of a radiative evolution for the Sardinian bovids.Results obtained,on the one hand,highlighted some inadequacies of the method if not applied to African bovids;on the other hand,they stressed the difficulties of discriminating habitat preferences of Sardinian taxa only based on biometry of astragalus and phalanges.Nonetheless,statistical habitat predictions suggest the contemporaneous presence in Sardinia of bovids having about the same size,but inhabiting different environments,giving support to the hypothesis that Sardinian representatives of the genus Nesogoral originated from a still unknown ancestor by an adaptive radiation evolutionary process.