نتایج جستجو برای: brachiopoda
تعداد نتایج: 272 فیلتر نتایج به سال:
Most studies of brachiopod evolution have been based on their extensive fossil record, but molecular techniques, due to their independence from the rock record, can offer new insights into the evolution of a clade. Previous molecular phylogenetic hypotheses of brachiopod interrelationships place phoronids within the brachiopods as the sister group to the inarticulates, whereas morphological con...
The genus Kassinella was established by Keller (1960: 90) for extinct Lower Carboniferous (Tournaisian) corals from Kazakhstan. The name, however, is preoccupied by the senior homonym Kassinella Borissiak (1956: 50) (Brachiopoda), equally honouring N. G. Kassin, famous geologist and explorer of Kazakhstan. To resolve the homonymy, in accordance with the International Code of Zoological Nomencla...
The order Billingsellida comprises brachiopods with laminar and fibrous shells, however, the data on their microstructure are scanty and the taxonomic value of differences in their shell structure is uncertain. The shell structure of clitambonitidine Antigonambonites planus was found to be laminar, not fibrous as previously considered; possibly this shows that it belongs to the suborder Billing...
Six brachiopod species, i.e., Discradisca sp., Cryptopora sp., Pliothyrina sp. cf. P. grandis (Blumenbach, 1803), Terebratulina tenuistriata (Leymerie, 1846), Rhynchonellopsis nysti (Bosquet, 1862), and Orthothyris pectinoides (von Koenen, 1894), have been identified in the Late Eocene to Early Oligocene Silberberg Formation of Atzendorf, Central Germany. The species R. nysti and O. pectinoides...
Maximum likelihood and Bayesian inference analyses of seven concatenated fragments of nuclear-encoded housekeeping genes indicate that Lophotrochozoa is monophyletic, i.e., the lophophorate groups Bryozoa, Brachiopoda and Phoronida are more closely related to molluscs and annelids than to Deuterostomia or Ecdysozoa. Lophophorates themselves, however, form a polyphyletic assemblage. The hypothes...
The lophophore, an essential organ of the Brachiopoda, has been used widely in evolutionary and advanced phylogenetic studies, but is hitherto unknown in the fossil record. Here, the extraordinarily well-preserved lophophores of two inarticulated brachiopods Lingulella chengjiangensis and Heliomedusa orienta, from the Lower Cambrian Chengjiang fauna (Yunnan, China) are described. These primitiv...
During the Late Devonian Biodiversity Crisis, the primary driver of biodiversity decline was the dramatic reduction in speciation rates, not elevated extinction rates; however, the causes of speciation decline have been previously unstudied. Speciation, the formation of new species from ancestral populations, occurs by two primary allopatric mechanisms: vicariance, where the ancestral populatio...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید