The Osteology and Phylogenetic Position of Luperosuchus fractus (Archosauria: Loricata) from the Latest Middle Triassic or Earliest Late Triassic of Argentina
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Abstract:
Large archosaurs from the early part of the archosaur radiation are exceedingly rare and with few exceptions, most of these remains consist of fragmentary postcrania. We redescribe the fragmentary skull of Luperosuchus fractus from the early Middle—Late Triassic Chañares Formation of Argentina, assign newly discovered fragments from the original excavation to the same individual, and analyze its phylogenetic affinities. The dorsally convex and mediolaterally compressed anterior portion of the nasal (= 'Roman-nose'), convex and circular knob on the dorsolateral margin of the postorbital, and a long anterior process of the prefrontal that fails to extend to the anterior end of the frontal are considered autapomorphies of Luperosuchus. The elongated gap between the nasal and maxilla is likely an artifact of preservation and this prompted a critical reevaluation of the supposed openings in the anterior portion of the skull of other suchians. We confirm that Luperosuchus is a loricatan (composed mostly of the taxa classically termed as 'rauisuchians') using a well sampled phylogeny and find a close relationship with the other large southwestern Pangean forms, Prestosuchus chiniquensis and Saurosuchus galilei. We also show that the holotype of Luperosuchus is the only known specimen of the taxon and all other previously referred material cannot be assigned with confidence to it.Keywords:
Autapomorphy
Osteology
Osteology
Paleopathology
Forensic anthropology
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SUMMARY 1. Support is cited for the establishment of a separate family, Chacidae comprising the monotypic genus Chaca based on the obtained osteological data. 2. The osteological characterisation of family Chacidae as well as genus Chaca is provided: very broad and depressed skull; very wide mouth gape bounded by unequal jaws; quite broad ethmoid with long and stout cornua; strongly projecting lateral ethmoid; toothless but conspicuous vomer; forked lachrymal; suborbitals lacking; very much reduced nasals; occipital process peculiarly modified. Movable premaxillae, quite large and broad palatine; minute ectopterygoid; hyomandibula solely sustained from the sphenotic; single hypohyal; eight branchiostegal rays; no basibranchials and gill-rakers and single pharyngobranchial. 3. The relationship of the family Chacidae with the Siluridae, Plotosidae, Bagridae and Sisoridae on the evidence of osteology is discussed and osteological support is found for its close affinity with the Sisoridae. 4. A brief discussi...
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Spinous process
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The cranial osteology of the ichthyosaurLeptonectescf.tenuirostrisfrom the Lower Jurassic of England
ABSTRACT For the first time, a three-dimensionally preserved skull of the Lower Jurassic leptonectid ichthyosaur Leptonectes cf. tenuirostris is described. The specimen reveals a wealth of new data on the cranial anatomy of basal leptonectid neoichthyosaurs. The osteology of the skull roof differs fundamentally from other well-known post-Triassic ichthyosaurs and is highly autapomorphic. The structure of the sclerotic ring, which is well preserved in situ, is described and it appears plausible that L. cf. tenuirostris was capable of stereoscopic vision. Inadequate description makes comparison to other leptonectids difficult. It can be demonstrated, however, that L. cf. tenuirostris is most similar to L. tenuirostris among known leptonectids. It is fundamentally different from the Upper Liassic Eurhinosaurus longirostris in the osteology of the skull roof and the size and orientation of the major skull openings, making generic distinction of these two species a necessity. At the moment, no autapomorphies are known of the genus Leptonectes, which therefore must be considered as a metataxon that comprises basal leptonectids from the Lower to Middle Liassic.
Osteology
Autapomorphy
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Base (topology)
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The difficullty to distinguish between sheep and goats is a well-known problem in archaeology and osteology. Distinguishing sheep and goats in archaeological animal remains takes time and time is often limited for osteologists. Because of this difficulty osteologists and archaeozoologists often use the term sheep/goat or ”ovicaprids” in their analytical reports. But even if the term sheep/goat comprise both species, this is often not the case when archaeologists and osteologists interpret and present archaeological findings. Sheep usually dominates in the interpretations and is often seen as a more important animal than goats which ultimately lead to false representations of the species and their relation to humans in the past.Zeder and Lapham (2010) have gathered criterias for post-cranial bone elements which show a high degree of reliability in osteological species determination between sheep and goats. However, when working on archaeological remains you do not know if the evaluation is done correctly. In this thesis, the use of ocular osteological methods from by Zeder and Lapham (2010) are combined with genetical analyzis of selected sheep and goat bones from an archaeological assemblage in order to evaluate how well these osteological methods perform and assess which criterias on the bone elements can be seen as reliable when used to distinguish between the species.According to the results, only three criterias of a total of 21 criterias are seen as reliable. It is also apparent that previous osteological experience is relevant for successfully distinguish between sheep and goat with these methods. However, several criterias show tendencies towards reliability and are probably affected by the small sample set for each bone element, few osteological analysts, and the fact that all genetically analyzed bones resulted in sheep.
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Aim: The development of bipedal position anatomically changed the entire skeleton, not only the legs and pelvis, but also the spine, feet and skull.By studying changes in the appearance of the skull and its volume we can monitor changes of brain volume and intelligence development and human evolution. Materials and methods: The research was conducted on a specimen of 196 macerated and degreased skulls, 82 of which belong to the osteological collection of the Department of Archeology – Chair of Prehistory, Antique Period and Middle Ages – of the State Museum of Bosnia and Herzegovina in Sarajevo. From the osteological collection of the department of Anatomy of the Medical Faculty in Sarajevo, a total of 114 skulls have been examined, 57 of which were skulls of male gender and 57 of female gender. On each of the examined skulls applying craniometrical method we estimated cranial capacity. Results : Regardless of the period in question, we have the highest variability in the category cranial capacity. It is actually a natural sequence due to the impact of all three linear dimensions (length, width and height) of the skull at its formation. Conclusions: Cranial capacity shows a growing tendency going to younger period of time from which the skull encouraged, except for a slight decline during the Middle Ages. Keywords: skull, cranial capacity, craniometry, prehistoric skull, antic period skull, middle ages skull, recent period skull
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