Search results for "tetrapod"

Theoretical morphology of tetrapod skull networks

2014

Abstract Network models of the tetrapod skull in which nodes represent bones and links represent sutures have recently offered new insights into the structural constraints underlying the evolutionary reduction of bone number in the tetrapod skull, known as Williston's Law. Here, we have built null network model-derived generative morphospaces of the tetrapod skull using random, preferential attachment, and geometric proximity growth rules. Our results indicate that geometric proximity is the best null model to explain the disparity of skull structures under two structural constraints: bilateral symmetry and presence of unpaired bones. The analysis of the temporal occupation of this morphosp…

Tetrapod trackways from Southern Egypt and Northern Sudan

1990

Abstract Tetrapod footprints were found in the Cretaceous strata-formerly called “Nuba(n) Sandstone” -of SE-Egypt and NW-Sudan. The trackways are here for the first time described in detail and in connection with their relative depositional environments. As the preservation of these footprints is poor, generic or specific names were not given. The name of the ichnogenus that comes closest to fitting the shape has been noted for each print. With respect to their paleoecological and stratigraphical significance, investigations of tetrapod footprints were necessarily concentrated on the continental strata of Egypt and Sudan. More discoveries will be welcome.

Ventastega curonica and the origin of tetrapod morphology.

2008

The gap in our understanding of the evolutionary transition from fish to tetrapod is beginning to close thanks to the discovery of new intermediate forms such as Tiktaalik roseae. Here we narrow it further by presenting the skull, exceptionally preserved braincase, shoulder girdle and partial pelvis of Ventastega curonica from the Late Devonian of Latvia, a transitional intermediate form between the 'elpistostegids' Panderichthys and Tiktaalik and the Devonian tetrapods (limbed vertebrates) Acanthostega and Ichthyostega. Ventastega is the most primitive Devonian tetrapod represented by extensive remains, and casts light on a part of the phylogeny otherwise only represented by fragmentary ta…

Design and synthesis of colloidal nanocrystal heterostructures with tetrapod morphology.

2006

Preliminary report on the microvertebrate faunal remains from the Late Triassic locality at Krasiejów, SW Poland

2019

Fossil vertebrate remains from the Keuper unit in the vicinity of the village of Krasiejów have been analyzed for almost two decades. However, the main goal of these works was focused mainly on large vertebrates. Here the authors present the first description of microvertebrate fossils from that site. The collection of around 5,000 specimens is mainly comprised of teeth and scales. The most numerous remains belong to osteichthyans: dipnoans (Ptychoceratodus and cf. Arganodus), palaeoniscids, semionotids, redfieldiids and chondrichthyans, such as Lonchidion sp., which is the first indisputable record of that genus in the Upper Triassic of Poland and the first shark at the Krasiejów locality.…