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Chimaeroid (Chondrichthyes: Holocephali) mandibular toothplates of Edaphodon kawai, sp. nov., are described from the Cretaceous-Paleogene Takatika Grit of Chatham Islands, New Zealand. This is the first description of a chimaeroid from the Chatham Islands-New Zealand region, extending the geographical and temporal range of this genus globally. The new species is defined by a straight toothplate and long robust beak, which is armed with a long laminated symphyseal tritor and has an elongate anterior outer tritor and a pronounced asymmetric ridge positioned mesially on the oral surface. This unique arrangement may reflect a feeding strategy of cutting and crushing, which differs from most previously identified callorhynchids that possess crushing surfaces only.
The evolutionary origin of the great white shark (Carcharodon carcharias) is unclear, with debate centering around two principal hypotheses. The first, based on similarity in tooth shape, claims that C. carcharias originated from a group of extinct mako sharks that includes Isurus hastalis. The second hypothesis, based mostly on cladistic evidence, claims that C. carcharias originated from the same lineage as the giant megatoothed sharks, sharing a close evolutionary ancestor with the extinct Carcharodon megalodon. To distinguish between the two hypotheses we performed several morphometric analyses. In the first analysis, we used Procrustes method and principal components analysis to quantify variation between C. carcharias, I. hastalis, and C. megalodon in four different positions within the dentition. The results indicate no significant difference in tooth shape between C. carcharias and I. hastalis. In the second analysis, correlating tooth size with age, we analyzed teeth from upper anterior and lower anterior positions. For both tooth positions, we show that the growth rate of C. carcharias is more congruent with the growth rate of I. hastalis than that of C. megalodon. Finally, we used scanning electron microscopy to show that the tooth serrations of C. carcharias are distinct from those of the megatooths and more similar in size to those of slightly serrated mako teeth. Taken together, these results indicate that C. carcharias originated from an extinct group of mako sharks and not from the megatoothed sharks.
A new species of pufferfish from the Miocene (Messinian) of Algeria is described. The single specimen available consists of a fragment of the trunk region including abdominal and caudal vertebrae, dorsal and anal fin pterygiophores, and ventral postcleithrum. It can be referred to the genus †Archaeotetraodon on the basis of its bifid scale spinules covering the preserved portion of the body. The skeletal morphology of this new species is compared to that of the previously known †Archaeotetraodon species and of selected extant tetraodontids and used to formulate hypotheses about the potential muscle arrangement in the trunk region, its significance for the functional morphology of swimming and puffing behaviour, and the possible origin of pufferfish.
The cranial anatomy of Lydekkerina huxleyi, a lydekkerinid stereospondyl from the Lower Triassic Lystrosaurus Assemblage Zone (Beaufort Group; Karoo Basin) of South Africa, is redescribed in detail following additional preparation of the poorly known holotype specimen. Whereas previous studies failed to identify any uniquely derived characteristics of L. huxleyi, three autapomorphies are identified herein: the presence of paired, anterodorsal projections within the anterior palatal vacuity, vomerine shagreen, and a series of thickened ridges on the ventral surface of the skull roof. The low ridge on the quadrate ramus of the pterygoid in L. huxleyi, previously identified as the crista obliqua homologous to that of mastodonsauroids, is reinterpreted in light of new observations on rhinesuchids. The mandible is described in detail for the first time and is shown to possess an extensive denticle shagreen on all three coronoid elements (as in primitive stereospondyls), and a distinctly elongated, prong-like arcadian process of the postglenoid area. Characters that show intraspecific variation in L. huxleyi include the contribution of the lacrimal to the narial margin, the presence of an ectopterygoid tusk, the degree of development of the transverse flange of the pterygoid, and the number of anterior meckelian foramina on the mandible. Redescription of L. huxleyi permits a reassessment of lydekkerinid species diversity in the Karoo Basin: ‘Broomulus dutoiti’ and ‘Limnoiketes paludinatans’ are regarded as subjective junior synonyms of L. huxleyi. Morphologically, Eolydekkerina magna resembles L. huxleyi more closely than had been initially suggested, and is cautiously regarded as a distinct taxon.
A new species of freshwater Testudinoidea is described from the fossil locality of Le Quesnoy (Oise, France; Argiles à Lignites du Soissonnais, Lower Eocene, Ypresian, MP7). This taxon is the oldest representative of Ptychogasteridae known from Europe. This species is compared to the American representatives of the genus EchmatemysHay, 1906, to three Ptychogasteridae from the Geiseltal Formation (Eocene, Germany; Geiselemys ptychogastroides [Hummel, 1935], “Geoemyda” saxonicaHummel, 1935 and Hummelemys ambiguaHervet, 2004b), and to representatives of the Ptychogaster complex and to ClemmydopsisBoda, 1927. The phylogenetic relationships of this new taxon and of the other European Ptychogasteridae are studied.
The Parareptilia, the sister group to the Eureptilia, is poorly known, with many taxa in need of adequate description. One such taxon, Macroleter poezicus is found in Middle Permian strata of the Mezen River Basin in the Arkhangel'sk Province of Russia. The cranial anatomy of Macroleter is described from four new well-preserved specimens, and 89 cranial characters are incorporated into a phylogenetic analysis of parareptiles. A single most parsimonious topology is found, consisting of 205 steps, with the novel result that Macroleter is the taxon most closely related to pareiasaurs. This result has important implications for the phylogeny of the Parareptilia as well as for the identity of a disputed element (the tabular) in the skull of pareiasaurs.
A new genus and species of protorosaur is described on the basis of material originally referred to Tanystropheus antiquus from the Upper Buntsandstein of the Black Forest, Germany. The new taxon is characterized by eight cervical vertebrae that bear markedly elongate cervical ribs, a shagreen of denticles covering the vomers, palatines and pterygoids, a bifurcate second sacral rib, a well-ossified tarsus with three distal tarsals, and an elongate proximal phalanx on digit five. The status of Tanystropheus antiquus is discussed and, while it is retained, its validity is questioned.
Two juvenile specimens of the pterodactyloid pterosaur Germanodactylus cristatus are identified from the Solnhofen Limestone of southern Germany. The specimens had been referred to the nominal species Pterodactylus kochi and P. micronyx. They have edentulous tips on the upper and lower jaws; their skulls are taller and less elongate and have fewer teeth than similarly sized specimens assigned to P. antiquus and P. micronyx; and they have tall neural spines on their cervical vertebrae. In addition, they exhibit a distinctive suite of skeletal proportions that distinguishes them from similarly sized specimens assigned to P. antiquus and P. micronyx. The specimens do not exhibit any trace of a cranial crest, which supports the interpretation that the cranial crest developed late in ontogeny, probably as the individual approached skeletal and/or sexual maturity. The taxonomy of Germanodactylus is reviewed and revised diagnoses are presented.
A reexamination of the French Compsognathus corallestris, from the Portlandian lithographic limestones of the Tithonian of southern France, provides new cranial and postcranial information crucial for a better understanding of the taxon Compsognathus. The French Compsognathus is almost completely preserved either as actual bony elements or as impressions, lacking only the distal portion of its tail, and some of the manual phalanges. It is preserved in two blocks, one containing the skull and postcranial skeleton up to the seventh caudal vertebra, the other caudal vertebrae nine through 31. Compsognathids are currently known from Europe, South America, and China. The absence of an external mandibular fenestra, dorsally fan-shaped dorsal neural spines with hook-shaped ligament attachments, and a very short McI and a PhI-1, which is stouter than the radius distinguish compsognathids from other coelurosaurs. Anatomical and morphological characters of the Bavarian specimen of Compsognathus are nearly identical to those of the French specimen. The differences are related to ontogenetic or within-species variation or are caused by preservational factors. Therefore this study proposes that C. corallestris is a subjective junior synonym of Compsognathus