Description of the tympanic regions of Paraechinus and Podogymnura

58 p. : ill. ; 24 cm.Includes bibliographical references (p. 56-58)."Although living hedgehogs have long been regarded [as] the archetypes of the primitive placental mammal, they have nonetheless had a complex Cenozoic history that is reflected in the recognition of three extinct and two living erinaceid subfamilies. Members of one extinct subfamily, the Brachyericinae, underwent a remarkable shortening of the skull and a reduction in the number of teeth during the Oligocene, Miocene, and early Pliocene. This trend culminated in the two North American genera, Brachyerix and Metechinus, in which only three teeth were retained anterior to P[subscript]4. Dimylechinus, a European form from the early Miocene, and Exallerix from the medial Oligocene of Asia both retained at least four teeth anterior to P[subscript]4. None of the four genera had an M[subscript]3. Brachyerix and Metechinus occur from the Great Plains to the Pacific coast of North America. Brachyerix is temporally restricted to the Miocene; Metechinus occurs in late Miocene and early Pliocene sediments. Although both genera are known from several localities, they are never found together, which may reflect an ecological separation of these two forms during temporal overlap. Both are known only from cranial osteology. During the past 40 years, the differences between these two North American genera have not been well defined, and only now with the availability of several specimens of each can the generic boundaries be adequately reviewed. Two species of Brachyerix are recognized in the present paper. Brachyerix macrotis, restricted to the early and medial Miocene, is the larger of the two and differs from B. incertis, new combination (late Miocene), in having a stronger lingual cingulum on P[superscript]3 and in entirely lacking a P[superscript]3 protocone. Metechinus marslandensis can now be synonymized with B. macrotis, whereas Talpa incerta and Metechinus fergusoni are both junior synonyms of B. incertis. Only Metechinus nevadensis still requires generic separation owing to its unique basicranium, small auditory bullae, nature of the sagittal crest, and relatively anteroposteriorly compressed M[subscript]1 trigonid. Dimylechinus bernoullii is an adequate structural ancestor for Brachyerix macrotis and its descendents. However, as both Dimylechinus and Exallerix are known only from single specimens, their relationship to the North American brachyericines as well as to one another is not well understood and will not be until further specimens are found. An appendix describing the ear regions of two living hedgehog genera, Paraechinus and Podogymnura, is included to supplement Butler's (1948) paper on the erinaceid ear region. Paraechinus is the only living erinaceid that has bony tubes covering part of the blood vessels contained in the tympanic cavity, a condition developed to the extreme in the Miocene Brachyerix"--P. [1]-2

New eucryptodiran turtle

35 p. : ill., maps ; 26 cm.Includes bibliographical references (p. 28-30).Chubutemys copelloi is the oldest nonmarine cryptodire from South America represented by a skull. The skull and associated postcranial fragments are from the Aptian Cerro CostaŠno Member of the Cerro Barcino Formation of Chubut, Argentina. Chubutemys has a processus trochlearis oticum, showing that it is a cryptodire, and an enclosed canalis caroticus internus extending to the posterior margin of the pterygoid, showing that it is a eucryptodire. The skull of Chubutemys is similar to that of other primitive eucryptodires, particularly Dracochelys, but also to Hangaiemys, Judithemys, Sinemys, and Ordosemys. Chubutemys differs from all these, however, in possessing a solidly roofed skull, formed by long, wide parietals, rather than a posterior emargination. Chubutemys also differs from these taxa in having no cheek emargination. A phylogenetic analysis using PAUP* analyzed 104 parsimony-informative characters resolving into one most parsimonious cladogram of 224 steps, a consistency index of 0.55, and a retention index of 0.74. The phylogenetic analysis weakly joins Chubutemys and meiolaniids on the basis of the prefrontal-postorbital contact. Chubutemys also has a fully roofed skull and slitlike posterior opening of the foramen caroticum laterale (foramen posterius canalis caroticus laterale), features to be expected in a meiolaniid sister taxon. Chubutemys provides further evidence that meiolaniids are related to 'basal' eucryptodires ('sinemydids/macrobaenids'), that is, eucryptodires outside the living Cryptodira, the Polycryptodira. The basicranial morphology of meiolaniids, with an intrapterygoid slit, rather than being a unique feature of the group is instead a modified state of the primitive eucryptodire condition, as seen in such forms as Chubutemys, Dracochelys, Ordosemys, and Sinemys. The intrapterygoid slit of meiolaniids is homologous with the pterygoid flange associated with the foramen caroticum laterale (foramen posterius canalis caroticus laterale of Sukhanov) in non-Polycryptodiran eucryptodires like Ordosemys. Chubutemys shows that nonmarine eucryptodires were present in South America in the Cretaceous, as they were in North America, central Asia, and Australia

Antarctic dispersal routes, wandering continents, and the origin of Australia\u27s non-passeriform avifauna

Volume: 36Start Page: 63End Page: 12

The Pliocene and Quarternary Flamingoes of Australia

Volume: 25Start Page: 207End Page: 22

The Australian Dromornithidae: a group of extinct large ratites

Volume: 330Start Page: 93End Page: 10

A new owlet-nightjar from the early to mid-Miocene of eastern New South Wales

Volume: 38Start Page: 247End Page: 25

A fossil plain wanderer (Aves: Pedionomidae) from fire-hole deposits, Morwell, southeastern Victoria, Australia

Volume: 330Start Page: 251End Page: 25