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Abstract: Patagoniaemys gasparinae gen. et sp. nov. is a new stem turtle found in central Patagonia, Chubut Province, Argentina, in outcrops of the La Colonia Formation (Campanian–Maastrichtian). This is a turtle of relatively large size (carapace length c. 70 cm), and the preserved remains of the holotype consist of skull fragments and several postcranial elements including a nearly complete vertebral column. A phylogenetic analysis shows Patagoniaemys gasparinae gen. et sp. nov. forming a monophyletic group with Otwayemys cunicularius and Mongolochelys efremovi, as a sister group to Meiolaniidae. A comprehensive review confirms that formed cervical vertebrae appeared independently several times during turtle evolution: in the clade that includes Patagoniaemys gasparinae gen. et sp. nov. and Meiolaniidae, in some baenids, in the total group Pleurodira and in crown group Cryptodira. Likewise, formed caudal vertebrae appeared several times in turtle evolution. 相似文献
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JUAN CARRANZA CONCHA MATEOS SUSANA ALARCOS CRISTINA B. SÁNCHEZ-PRIETO JULIANA VALENCIA 《Biological journal of the Linnean Society. Linnean Society of London》2008,93(3):487-497
Worn teeth in herbivore ungulates may be related to lower efficiency in mastication and hence lower performance. However, selection should favour maximal performance in terms of body mass and reproductive capacity during reproductive lifespan, when permanent teeth are already partially worn. We hypothesize that wear rate may respond to a strategy of use of tooth materials (notably dentine), which balances instantaneous wear rate and performance against tooth preservation for future performance and reproduction. In the present study, we investigated 4151 carcasses of Iberian red deer Cervus elaphus hispanicus and show that more worn molars were not related to lower performance throughout age. By comparing between sexes, tooth wear rates were smaller in females than in males, but the relationship between tooth wear and body performance also differed between the sexes: females did not show a significant relationship between tooth wear and performance but males with more worn teeth were in general heavier and had larger antlers until senile age, when more depleted teeth were related to smaller antlers. These results reveal, for the first time, sex-specific lifetime strategies of dentine expenditure: maintenance of performance ability throughout a longer reproductive lifespan in females, compared with maximizing current performance by depleting dentine reserves within a shorter lifespan in males. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 487–497. 相似文献
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JULIANA DE PAULA-SOUZA VINICIUS CASTRO SOUZA 《Botanical journal of the Linnean Society. Linnean Society of London》2003,141(4):503-506
A new species of Hybanthus (Violaceae) from north-eastern Brazil is described and illustrated. Hybanthus verrucosus Paula-Souza is endemic to 'caatingas' of Bahia and Alagoas states and is very distinct from all other Brazilian species of the genus, for its anterior petal, which is covered with small wart-like outgrowths. Other distinctive characteristics of the new species and its relationship with a closely related species ( H. atropurpureus (A.St.-Hil.) Taub.) are discussed. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 141 , 503–506. 相似文献
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HEYO VAN ITEN VICTOR P. TOLLERTON JR CHARLES A. VER STRAETEN JULIANA
De MORAES LEME MARCELLO GUIMARAES SIMÕES SABRINA COELHO RODRIGUES 《Palaeontology》2013,56(1):29-48
Abstract: Exceptionally abundant specimens of Conularia aff. desiderata Hall occur in multiple marine obrution deposits, in a single sixth‐order parasequence composed of argillaceous and silty very fine sandstone, in the Otsego Member of the Mount Marion Formation (Middle Devonian, Givetian) in eastern New York State, USA. Associated fossils consist mostly of rhynchonelliform brachiopods but also include bivalve molluscs, orthoconic nautiloids, linguliform brachiopods and gastropods. Many of the brachiopods, bivalve molluscs and conulariids have been buried in situ. Conulariids buried in situ are oriented with their aperture facing obliquely upward and with their long axis inclined at up to 87 degree to bedding. Most specimens are solitary, but some occur in V‐like pairs or in radial clusters consisting of three specimens, with the component specimens being about equally long or (less frequently) substantially different in length. The compacted apical end of Conularia buried in situ generally rests upon argillaceous sandstone. With one possible exception, none of the examined specimens terminates in a schott (apical wall), and internal schotts appear to be absent. The apical ends of specimens in V‐like pairs and radial clusters show no direct evidence of interconnection of their periderms. The apical, middle or apertural region of some inclined specimens abuts or is in close lateral proximity to a recumbent conulariid or to one or more spiriferid brachiopods, some of which have been buried in their original life orientation. The azimuthal bearings of Conularia and nautiloid long axes and the directions in which conulariids open are nonrandom, with conulariids being preferentially aligned between 350 and 50 degree and with their apertural end facing north‐east, and nautiloids being preferentially aligned between 30 and 70 degree. Otsego Member Conularia were erect or semi‐erect, epifaunal or partially infaunal animals, the apical end of which rested upon very fine bottom sediment. The origin of V‐like pairs and radial clusters remains enigmatic, but it is probable that production of schotts was not a regular feature of this animal’s life history. Finally, conulariids and associated fauna were occasionally smothered by distal storm deposits, under the influence of relatively weak bottom currents. 相似文献