Wyniki wyszukiwania - Biblioteka Nauki

Ten serwis zostanie wyłączony 2025-02-11.

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

4 Acta Palaeontologica Polonica

Znaleziono wyników: 4

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: Carnian

Sortuj według:

Ogranicz wyniki do:

Cynodont teeth from the Carnian [Late Triassic] of Northern Italy

100%

Renesto S. , Lucas S. G.

nr 2

357-360

A jaw fragment with three teeth preserved, collected from the Gorno Formation (Carnian, Upper Triassic) of Lombardy (Italy) is described. The teeth are transversely elongated, threecusped and bear anterior and posterior cingula. Their overall morphology supports their identification as postcanines of a “eucynodontian”. The unique tooth morphology of the new specimen supports its attribution to a new genus and species, while at the same time precluding positive assignment to already known gomphodont families. There is a fairly small record of gomphodont cynodonts in Europe, so that the described specimen adds to the knowledge of the distribution and diversity of European gomphodonts and it also represents the first ever collected in Italy.

Functional morphology and biomechanics of the cynodont Trucidocynodon riograndensis from the Triassic of Southern Brazil: Pectoral girdle and forelimb

80%

de Oliveira T. V. , Schultz C. L.

tom 61

nr 2

Non-mammalian cynodonts provide insights on several points about mammalian evolution, such as the postural change and locomotory advances within the group. Unfortunately, complete skeletons of Triassic cynodonts are rather uncommon and where more complete specimens are found they can offer a global vision on some traits not available from partial specimens. This is the case of the cynodont Trucidocynodon riograndensis, from the Triassic of Brazil, that has preserved its forelimbs providing some insights into locomotory properties. The movements between interclavicle and clavicle must have been limited, as such as those occurring between the latter and the scapulocoracoid although the long acromion process of this should have permitted a greater degree of freedom. Some of the more significant movements were those on the shoulder joint, in which the maximum adduction should have been ca. 35º relative to the parasagittal plane and the greater abduction ca. 55º. The maximum adduction occurred when the humerus was in the more retracted position during stride and the variation in the adduction/abduction should have been significant to the limb posture during its recovery stroke. The long olecranon and the distal overlapping between radius and ulna suggest the predominance of simple flexion/extension on the forearm without significant pronation/supination. The poorly preserved hand suggests that Trucidocynodon could have evolved a slight semidigitigrad condition in its forelimbs. All these features give to this cynodont an important role in the evolution of the mammalian locomotory properties indicating that some features, such as the possibility of greater humeral adduction, evolved early in cynodont lineage.

The first ornithosuchid from Brazil and its macroevolutionary and phylogenetic implications for Late Triassic faunas in Gondwana

80%

Muller R. T. , Belen von Baczko M. , Desojo J. B. , Nesbitt S. J.

nr 1

A new Metapolygnathus platform conodont species and its implications for Upper Carnian global correlations

80%

Mazza M. , Rigo M. , Nicora A.

tom 56

nr 1

A rich conodont fauna from two Neotethyan sections, Pizzo Mondello (western Sicily, Italy) and Pignola 2 sections (southern Apennines, Italy) includes conodonts described herein as a new species. Metapolygnathus praecommunisti sp. nov. is transitional between Paragondolella noah and Metapolygnathus communisti. The genus Metapolygnathus (including M. praecommunisti) is now characterised by posterior prolongation of the keel termination, associated with a centrally located pit and with a weak ornamentation confined to the anterior part of the platform margins. The establishment of M. praecommunisti addresses the problems related to the origin and the peculiar, probably facies−controlled, distribution of its descendant species M. communisti. Since M. praecommunisti occurs in the entire Tethys and in North America, we propose the species as a good guide fossil for global correlations, characterised by a short temporal range limited to the uppermost Tuvalian (upper Carnian). The stratigraphic occurrence of the genus Metapolygnathus is restricted to the Tuvalian–Lacian (upper Carnian–lower Norian), excluding its presence in the Julian substage (lower Carnian).