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Wyszukujesz frazę "dentary" wg kryterium: Wszystkie pola


Wyświetlanie 1-4 z 4
Tytuł:
New partial dentaries of amphitheriid mammal Palaeoxonodon ooliticus from Scotland, and posterior dentary morphology in early cladotherians
Autorzy:
Panciroli, E.
Benson, R.B.J.
Butler, R.J.
Powiązania:
https://bibliotekanauki.pl/articles/22338.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
We describe two partial dentaries of mammals from the Middle Jurassic of Scotland. They belong to the early cladotherian Palaeoxonodon ooliticus. These dentaries comprise the first specimen of P. ooliticus ever found—although its significance was initially unrecognised so it remained undescribed until now—and the most recently discovered specimen, found during fieldwork in 2017. The new specimen preserves part of the coronoid process of the dentary, previously unknown for P. ooliticus, demonstrating the presence of a deep masseteric fossa, with a prominent crest enclosing the fossa anteriorly, and a masseteric foramen, located in the masseteric fossa on the buccal surface of the dentary. On the lingual surface, the mandibular foramen is offset from the Meckel’s sulcus, and positioned below the alveolar plane. These morphologies allow an updated analysis of the phylogenetic position of P. ooliticus, confirming a sister-taxa relationship between Palaeoxonodon and Amphitherium. The position of the mandibular foramen, and the slight extension of the masseteric fossa into the body of the dentary are new autapomorphies for Palaeoxonodon.
Źródło:
Acta Palaeontologica Polonica; 2018, 63, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A unique dentary suggests a third genus of batrachosauroidid salamander existed during the latest Cretaceous in the western USA
Autorzy:
Gardner, James D.
Powiązania:
https://bibliotekanauki.pl/articles/2216212.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Lissamphibia
Caudata
Batrachosauroididae
Cretaceous
Maastrichtian
Lance Formation
North America
Opis:
An incomplete salamander dentary (AMNH FARB 22965) described herein from the upper Maastrichtian Lance Formation, Wyoming, USA, exhibits a puzzling suite of features. Four features—a prominent bony trough extending anteriorly and curving upwards along the lingual surface of the ramus, lack of an obvious Meckelian fossa or groove, an apparent gap in the tooth row, and a symphysial-like first tooth—are likely anomalies. However, the remaining features are interpreted as normal structures and suggest that AMNH FARB 22965 represents a new genus and species of batrachosauroidid, an extinct family of neotenic salamanders that were prominent components of Cretaceous to Neogene freshwater and floodplain paleocommunities in North America and Europe. The new taxon differs from other batrachosauroidids in a unique suite of dentary and dental features, most notably in having a lingual bony flange paralleling the posterior two-thirds of the dentary tooth row, a prominent and robust coronoid process bearing a grooved anterior face, and the anterior portion of the corpus dentalis behind the symphysis is broadly expanded ventrolingually. The presence of a third batrachosauroidid taxon in the Lance Formation was unexpected, considering that the formation has been well sampled and that its two previously recognized batrachosauroidids, namely Opisthotriton kayi and Prodesmodon copei, are known by abundant isolated bones, including dozens of dentaries, from numerous localities in the unit and elsewhere in the North American Western Interior. Known by a unique dentary from the Bushy Tailed Blowout locality, the taxon represented by AMNH FARB 22965 evidently was uncommon within the Lance Formation paleoenvironment.
Źródło:
Acta Palaeontologica Polonica; 2022, 67, 1; 35-50
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discovery of Middle Jurassic mammals from Siberia
Autorzy:
Averianov, A O
Lopatin, A.V.
Skutschas, P.P.
Martynovich, N.V.
Leshchinskiy, S.V.
Rezvyi, A.S.
Krasnolutskii, S.A.
Fayngertz, A.V.
Powiązania:
https://bibliotekanauki.pl/articles/945775.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
docodonta
morganucodon
dentary
anatomy
bathonian
jurassic
siberia
Opis:
Mammal remains from the Middle Jurassic (Bathonian) Berezovsk Quarry on the south of Krasnoyarsk Territory, West Siberia, Russia are referred to Docodonta indet. (two edentulous fragmentary dentaries) and Mammalia indet. (a single−rooted tooth). The dentaries exemplify a unique combination of plesiomorphic characters found among stem mammals only in Docodonta and Morganucodon: well developed Meckel’s groove, trough for postdentary bones with overhanging medial ridge and a diagonal ridge on the floor separating the “adductor fossa” and angular facet, and well developed and posteroventrally directed pseudangular process with facet for the reflected lamina of angular. Both specimens share with Docodonta the prearticular facet placed ventral to the angular facet and extending posteriorly to the mandibular foramen. This facet is not present in Morganucodon, where the prearticular lies medial to the angular. Medial position of the prearticular in Morganucodon is connected with the compound jaw articulation in this genus, in which a rudimentary articular−quadrate mandibular joint is present medially to the dentary−squamosal joint. In Docodonta indet. from Berezovsk Quarry, Haldanodon and Docodon the position of the prearticular ventral to the angular is connected with the position of the articular complex ventral to the dentary condyle. Such articular complex could not function as a mandibular joint and postdentary bones in Docodonta were used solely for sound transmission. One specimen from Berezovsk Quarry shares with Morganucodon a groove for replacement dental lamina, which was not reported previously for Docodonta. Mammal remains from Berezovsk Quarry are among the oldest occurrences for Docodonta, the first record of Jurassic mammals for Siberia, and only second such record for the whole of Russia.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 4; 789-797
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Marsupials from the Late Cretaceous of Uzbekistan
Autorzy:
Averianov, A
Kielan-Jaworowska, Z
Powiązania:
https://bibliotekanauki.pl/articles/23052.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
dentary fragment
Cretaceous
Late Cretaceous
Uzbekistan
Marsasia
Marsasia aenigma
Asiadelphia
marsupial
paleontology
paleobiogeography
Opis:
A fragment of dentary with m4, showing characters of some Late Cretaceous North American marsupials, is assigned to Marsasia sp. Marsasia Nessov, 1997 from the Coniacian of Uzbekistan, represented by M. aenigma known from edentulous dentaries with inflected angular processes, was attributed by Nessov to ?Marsupialia. Marsasia sp., found in the same horizon as the type species, resembles it in size and structure of the masseteric fossa, but dffiers in having a less steep coronoid process. We assign Marsasia to Marsupialia on the basis of the following characters: inflected angular process, shape of the dentary similar to that in Asiatherium, postcanine dental formula, inferred from alveoli for p1-3, ml-4, and sfructure of m4 more similar to Cretaceous marsupials than eutherians. The phylogenetic position of Marsasia may be between the Albian Kokopellia and Campanian Asiatherium. Marsasia is tentatively referred to the orderAsiadelphia, which may represent an endemic Asian marsupial clade.
Źródło:
Acta Palaeontologica Polonica; 1999, 44, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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