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EN
Ichthyosaurs were highly adapted to a marine lifestyle, as shown by their fish-like body shape and their assumed active swimming abilities and high metabolic rates. However, the processes of adaptation to an aquatic life in the early stages of this lineage remain poorly understood. Here, we present the first osteohistological data concerning the most basal ichthyopterygian yet known, Utatsusaurus hataii, from the Lower Triassic of Japan. The cancellous bone structure suggests adaptation to active swimming in an open marine environment. Moreover, the possible occurrence of rapidly deposited bone tissue, in a fibrolamellar complex, suggests a higher metabolic rate than in modern poikilothermic reptiles, and therefore a trend toward homeothermy. This basal ichthyosaur, with its elongate body, was already more adapted to an aquatic lifestyle than expected from its morphology, and the process of adaptation to a marine lifestyle was already well advanced by the Early Triassic.
EN
The subfamily Murininae has high species diversity in Vietnam, but taxonomic studies are limited. In this paper, we describe a new species of the genus Murina based on a specimen collected from Ngoc Linh Nature Reserve, Kon Tum Province in the Central Highlands of Vietnam. It is a medium-sized species with ‘suilla-type’ dentition. A taxonomic review of Murininae from Vietnam was also conducted based on combined morphological, DNA, and karyological characteristics. Molecular phylogenetic analyses based on the mitochondrial cytochrome c oxidase subunit (COI) gene supported the subfamily Murininae, while the genus Murina proved to be paraphyletic in relation to the genera Harpiocephalus and Harpiola. Fourteen species of the genus Murina, one species of Harpiocephalus, and one species of Harpiola are recognized from Vietnam. Murina tiensa is regarded as a junior synonym of M. harrisoni; strong sexual dimorphism was observed in M. harrisoni. Relations between forearm length and total length of skull showed different trends among species and sexes. Karyotypes of Murina huttoni, M. cyclotis, M. lorelieae, M. beelzebub, M. feae, and Harpiola isodon were 2n = 44, FN = 50, while that of Harpiocephalus harpia was 2n = 44, FN = 52.
EN
During the examination of a series of specimens, formerly referred to Myotis montivagus, recently collected in Vietnam and Lao PDR, we found that they differ in several important ways from any species formerly included in M. montivagus. We describe them as a new species characterised by a relatively long forearm, moderately long ears, flat cranial profile and wide anteorbital bridge. Based on characters classically used to separate the ‘subgenera’ of Myotis the new species shows affinities to both the nominate subgenus ‘Myotis’ and ‘Selysius’. Our morphological investigations support recent phylogenetic analyses showing that the former ‘subgenera’ of Myotis are in fact paraphyletic groups, even within Southeast Asia. Nevertheless, many of the external and craniodental features formerly used to separate these subgenera provide a practical means of grouping species. Using these characters we provide an identification key to identify the new species, as well as other currently recognized medium and large sized, small-footed Myotis species from the Indomalayan Region.
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