Nowe badania z niespodzianka dla Mixsa:o)

Dyskusje na temat gadów kopalnych (oprócz dinozaurów).
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Daniel Madzia
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Jurajski allozaur
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Nowe badania z niespodzianka dla Mixsa:o)

Post autor: Daniel Madzia »

:!: Jalil, N.-E., and Peyer, K. 2007. A new rauisuchian (Archosauria, Suchia) from the Upper Triassic of the Argana Basin, Morocco. Palaeontology 50(2):417-430. doi: 10.1111/j.1475-4983.2007.00640.x. :!:

ABSTRACT: In the 1970s the Upper Triassic strata of the Argana Basin yielded archosaurian remains that were tentatively attributed to the rauisuchian Ticinosuchus. Restudy of this material together with new remains reveal new anatomical data and show that it in fact belongs to a new taxon, Arganasuchus dutuiti gen. et sp. nov. The systematics of the Rauisuchia are still unresolved; nevertheless, a monophyletic suprageneric group can be defined within the probable non-monophyletic rauisuchians. Arganasuchus dutuiti differs from all adequately known rauisuchians in three autapomorphies: acetabular rim on pubis runs anteroventrally parallel to pubic shift rather than being terminal and perpendicular to it; large contribution of pubis to acetabular depression; palatal process of maxillary low and confluent with interdental crest, rather than separated from it by a large area. The maxilla of Arganasuchus resembles those of Batrachotomus and Fasolasuchus in having a Y-shaped rather than a U-shaped form. As in rauisuchids, Arganasuchus dutuiti has short cervical vertebrae and a dorsal border of the proximal extremity of the pubis that is convex in lateral view. It shares one derived character state with Batrachotomus and Postosuchus (a tear-shaped and anteriorly orientated rugosity on the lateral side of the pubis, lying on a deep, longitudinal depression) and one more derived character state with Batrachotomus (narrow ante-acetabular part of the pubis; hence, the anterior border of the proximal extremity of the pubis is almost contiguous with the actabular rim).

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Danilov, I.G., and Parham, J.F. 2007. The type series of 'Sinemys' wuerhoensis, a problematic turtle from the Lower Cretaceous of China, includes at least three taxa. Palaeontology 50(2):431-444. doi: 10.1111/j.1475-4983.2006.00632.x.

ABSTRACT: We re-examine the type series of 'Sinemys' wuerhoensis Yeh (at least 20 specimens, including several shells and skulls on three slabs of matrix and one isolated skull) from the Early Cretaceous Tugulu Group of China. Our study shows that the type series of 'S.'wuerhoensis is actually a chimera made up of at least three distinct taxa. The holotype of this taxon should be assigned to the basal eucryptodire genus Xinjiangchelys Yeh. As there are no characters that distinguish 'S.'wuerhoensis from Xinjiangchelys species, we consider it to be a nomen dubium. This new assignment of 'S.'wuerhoensis expands the temporal range of Xinjiangchelys from the Late Jurassic into the Early Cretaceous in Asia. The majority of the paratypes of 'S.'wuerhoensis (several shells in dorsal and ventral aspect and skulls) are referred to the basal eucryptodire genus Ordosemys Brinkman and Peng. We establish a new name for these specimens, Ordosemys brinkmania sp. nov. One additional specimen in the type series of 'S.'wuerhoensis, a skull, is referred to cf. Pantrionychia Joyce, Parham and Gauthier indet.

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Christiansen, P. 2007. Long-bone geometry in columnar-limbed animals: allometry of the proboscidean appendicular skeleton. Zoological Journal of the Linnean Society 149(3):423-438. doi: 10.1111/j.1096-3642.2007.00249.x.

ABSTRACT: Limb-bone allometry was investigated for 19 species of proboscideans, spanning almost the entire phylogenetic spectrum. More archaic proboscideans ('gompthotheres') have substantially thicker long-bone diaphyses relative to length than elephantids, as has been suggested previously, but contrary to previous suggestions it could not be confirmed that Mammuthus had more massive long-bone diaphyses on average than extant Elephas and Loxodonta. When correcting for phylogeny, the circumference of the limb bones to their length in proboscideans as a group generally scale with negative allometry, becoming stouter with increased length, as would be expected from limb mechanics. Few slopes were, however, statistically significantly negatively allometric. Correcting for phylogeny produced better correlations than traditional regression analyses, in contrast to most other studies where the reverse is the case. Intraspecific analyses of extant Elephas and Loxodonta, in addition to Mammuthus primigenius, Mammut americanum, and Gomphotherium productum, also resulted in negatively allometric regression slopes, frequently conforming to the theory of elastic similarity, as could be expected from the columnar posture of proboscideans. At present the reasons for the more massive limbs of gomphotheres s.l. are not fully understood.

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Pol, D., and Norell, M.A. 2007. Uncertainty in the age of fossils and the stratigraphic fit to phylogenies. Systematic Biology 55(3):512-521. doi: 10.1080/10635150600755446.

ABSTRACT: The ages of first appearance of fossil taxa in the stratigraphic record are inherently associated to an interval of error or uncertainty, rather than being precise point estimates. Contrasting this temporal information with topologies of phylogenetic relationships is relevant to many aspects of evolutionary studies. Several indices have been proposed to compare the ages of first appearance of fossil taxa and phylogenies. For computing most of these indices, the ages of first appearance of fossil taxa are currently used as point estimates, ignoring their associated errors or uncertainties. The effect of age uncertainty on measures of stratigraphic fit to phylogenies is explored here for two indices based on the extension of ghost lineages (MSM* and GER). A solution based on randomization of the ages of terminal taxa is implemented, resulting in a range of possible values for measures of stratigraphic fit to phylogenies, rather than in a precise but arbitrary stratigraphic fit value. Sample cases show that ignoring the age uncertainty of fossil taxa can produce misleading results when comparing the stratigraphic fit of competing phylogenetic hypotheses. Empirical test cases of alternative phylogenies of two dinosaur groups are analyzed through the randomization procedure proposed here.

d_m

czaszka neoaetozauroida

Post autor: d_m »

Daniel Madzia pisze::!: Jalil, N.-E., and Peyer, K. 2007. A new rauisuchian (Archosauria, Suchia) from the Upper Triassic of the Argana Basin, Morocco. Palaeontology 50(2):417-430. doi: 10.1111/j.1475-4983.2007.00640.x. :!:
CzÄ?sto przeglÄ?dajÄ?c witryny periodyk??w mo??na natrafiÄ? na darmowe pr??bki ca??kiem nowych numer??w. Palaeontology udostÄ?pni?? tegoroczny zeszyt styczniowy, a w nim min. opis czaszki kuzyna krasiejowskiego stagonolepisa - Neoaetosauroides engaeus, zawierajÄ?cy te?? informacje o sporej r????norodno??ci w??r??d aetozaur??w. Moim zdaniem wynika z tego wszystkiego co tam piszÄ?, ??e s??uszno??Ä? chyba majÄ? ci, kt??rzy podejrzewajÄ? aetozaury (jako ca??Ä? grupÄ?) o wszystko??erno??Ä?. U tego za?? konkretnego gatunku zÄ?by na ko??ci przedszczÄ?kowej dochodzÄ? prawie do czubka pyszczka, wiÄ?c keratynowego dziobu, tu przynajmniej, nie by??o. Opis szkieletu postkranialnego wyszed?? w Ameghiniana w 2005 roku (po hiszpa??sku :(): http://www.scielo.org.ar/scielo.php?scr ... so&tlng=es
Obrazek
Ostatnio zmieniony 17 marca 2007, o 19:08 przez d_m, łącznie zmieniany 1 raz.

Awatar użytkownika
Daniel Madzia
Jurajski allozaur
Jurajski allozaur
Posty: 1609
Rejestracja: 15 marca 2006, o 12:39
Lokalizacja: Třinec, Česká republika
Kontakt:

Re: czaszka neoaetozauroida

Post autor: Daniel Madzia »

Daniel Madzia pisze::!: Jalil, N.-E., and Peyer, K. 2007. A new rauisuchian (Archosauria, Suchia) from the Upper Triassic of the Argana Basin, Morocco. Palaeontology 50(2):417-430. doi: 10.1111/j.1475-4983.2007.00640.x. :!:
BTW, gdyby mial ktos przypadkowo te prace, bardzo chetnie bym poczytal. :)

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EDIT 18.3.
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OK, juz nie trzeba... mam ja :wink:

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