RESUMO
Scolecophidia (worm snakes) are a vertebrate group with high ecomorphological conservatism due to their burrowing lifestyle. The Eurasian or Greek blindsnake Xerotyphlops vermicularis is their only European representative, a species-complex with an old diversification history. However, its systematics and taxonomy has remained untouched. Here, we extend previous work that relied heavily on mitochondrial markers, following a multi-locus approach and applying several species-delimitation methods, including a Bayesian coalescence-based approach (STACEY). Four "species" delimitation analyses based on the mtDNA (ABGD, bGMYC, mPTP, parsimony networks) returned 14, 11, 9 and 10 clusters, respectively. By mitotyping twice as many specimens as before, we have a complete picture of each cluster's distribution. With the exception of the highly-divergent Levantine lineage, the three independent nuclear markers did not help with phylogenetic resolution, as demonstrated in haplotype networks, concatenated and species-trees, a result of incomplete lineage sorting. The prevailing model from the coalescence-based species-delimitation identified two species: the lineage from the Levant and all others. We formally recognize them as distinct species and resurrect Xerotyphlops syriacus (Jan, 1864) to include the Levantine blindsnakes. Finally, X. vermicularis and X. syriacus may represent species-complexes themselves, since they include high levels of cryptic diversity.
Assuntos
Tipagem Molecular , Filogenia , Serpentes/classificação , Serpentes/genética , Animais , Teorema de Bayes , DNA Mitocondrial/genética , Variação Genética , Haplótipos , Mitocôndrias/genética , Especificidade da EspécieRESUMO
Crested newts of the Triturus karelinii group occur in a phylogeographically understudied region: the Near East. Controversy surrounds the systematic position of these newts within the complete crested newt assemblage (the Triturus cristatus superspecies). We explore the situation using mitochondrial sequence data (ND2 and ND4, approximately 1.7kb) and employing different methods of phylogenetic inference (Bayesian inference and Maximum Likelihood using mixed models) and molecular dating (r8s and BEAST). The T. karelinii group is monophyletic and constitutes one of four main lineages in the T. cristatus superspecies. The separation of the T. karelinii group from the remaining crested newts around 9Ma is related to the formation of the Mid-Aegean Trench, which separated the Balkan and Anatolian landmasses. The T. karelinii group comprises three geographically structured clades (eastern, central and western). The genetic divergence shown by these clades is comparable to that among recognized crested newt species. We suggest the uplift of the Armenian Plateau to be responsible for the separation of the eastern clade around 7Ma, and the re-establishment of a marine connection between the Black Sea and the Mediterranean at the end of the Messinian Salinity Crisis to have caused the split between the central and western clade around 5.5Ma. Genetic structuring within the three clades dates to the Quaternary Ice Age (<2.59Ma) and is associated with alternating periods of isolation and reconnection caused by periodic changes in sea level and surface runoff.
Assuntos
Evolução Molecular , Variação Genética , Filogenia , Salamandridae/classificação , Animais , Teorema de Bayes , DNA Mitocondrial/genética , Geografia , Haplótipos , Funções Verossimilhança , Oriente Médio , Salamandridae/genética , Alinhamento de Sequência , Análise de Sequência de DNARESUMO
Order Chiroptera is the second largest mammal group after rodents. An understanding of the development of the bats, which is a very special mammal group in terms of their lifestyles, morphology and their ability to fly, is very important because most of the adult anatomical differences characterizing species occur during organogenesis. In this study, developmental stages were determined for Myotis myotis species based on external morphological characteristics from embryos obtained from wild-caught pregnant females. The developmental stages of M. myotis were comparable with those of other bat species.
Assuntos
Quirópteros/embriologia , Animais , Feminino , Membro Posterior/embriologia , Pigmentação , Gravidez , Cauda/embriologia , Asas de Animais/embriologiaRESUMO
Cystic masses of the mediastinum are a heterogenous group of asymptomatic or symptomatic, congenital, infectious, or neoplastic lesions. For early and correct diagnosis, evaluation, and optimal patient management of cystic mediastinal masses in infants, children, or adults imaging plays an important role. A non-invasive and sensitive imaging modality is an efficient and cost-effective tool. Multidetector computed tomography (MDTC) with volumetric acquisition provides fast acquisition of high resolution images and multiplanar reconstruction. Both 2D and 3D imaging in mediastinal imaging help in surgical planning and assessing resectability of mediastinal lesions. MR imaging has many advantages over other modalities for detecting and identifying cystic, or fluid-filled mediastinal masses, because of its intrinsic high soft tissue contrast and direct multiplanar imaging capabilities. However, histological tissue analysis may be required to differentiate a cystic lesion from other cyst-like or low-attenuation lesions.
RESUMO
The newts Triturus vulgaris and Triturus montandoni are sister species that exhibit contrasting levels of intraspecific morphological variation. Triturus vulgaris has a broad Eurasiatic distribution encompassing both formerly glaciated and unglaciated areas and shows substantial morphological differentiation in the southern part of its range, while T. montandoni, confined to the Carpathians, is morphologically uniform. We analysed sequence variation of two mtDNA fragments of the total length of c. 1850 bp in 285 individuals of both species collected from 103 localities. Phylogenetic analysis of 200 unique haplotypes defined 12 major clades, their age estimated at c. 4.5-1.0 million years (Myr). Most of the older clades were found in the southern part of the range, and also in central Europe, mainly in Romania. The distribution of mtDNA clades points to the existence of several glacial refugia, located in the Caucasus region, Anatolia, the Balkan Peninsula, Italy, and more to the north in central Europe. The concordance between mtDNA based phylogeny and the distribution of T. vulgaris subspecies was weak. Triturus montandoni haplotypes did not form a monophyletic group. Instead they were found in six clades, in five of them mixed with T. vulgaris haplotypes, most likely as a result of past or ongoing hybridization and multiple introgression of mtDNA from T. vulgaris to T. montandoni. Patterns of sequence variation within clades suggested long-term demographic stability in the southern groups, moderate and relatively old demographic growth in the populations inhabiting central Europe, and high growth in some of the groups that colonized northern parts of Europe after the last glacial maximum.