Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact email@example.com with any questions.
Variations in craniodental morphology have been correlated to feeding adaptations in living organisms and used as proxies for paleodiet reconstruction. Within the mammalian order Carnivora, the Miocene fossil musteloid Leptarctus has been variably interpreted as a carnivore, frugivore, herbivore, omnivore, or insectivore based on morphological comparisons with extant species. Here, we perform the first simulation of cranial biomechanics in Leptarctus primus, aiming to identify a living analogue using biomechanical capability rather than qualitative morphology. Finite element models (FEMs) of 18 extant carnivorans and two extinct outgroup taxa were used to compare known dietbiomechanics relationships with the biomechanical properties of L. primus FEMs within a phylogenetic context. Multivariate analyses of simulated bite efficiency and skull stiffness values indicate that L. primus is most similar overall to Taxidea taxus (American badger) in unilateral bite simulations. Based on biomechanical predictions, we postulate that L. primus resembled the American badger in its feeding ecology more closely than any other taxon tested and thus conclude that L. primus was dominantly a carnivore with an auxiliary feeding capability of omnivory. We also compared the L. primus FEMs with the potentially synonymous Hypsoparia bozemanensis to determine a possible range of feeding capabilities. We observed an increase in mechanical efficiency with a deepening of the zygomae of H. bozemanensis, a trait previously used to differentiate it from L. primus. Ongoing work to expand the database of cranial biomechanical simulation data across Carnivoramorpha should help to further clarify evolutionary patterns of skull biomechanical specializations in musteloids and other carnivorans.
Recent field work in the upper Permian Moradi Formation of Niger has yielded new material of the lateoccurring and largest moradisaurine captorhinid, Moradisaurus grandis. The material includes two right hemimandibles, which represent individuals that are slightly smaller than the holotype. The smaller size of these mandibles, together with evidence in the form of tooth replacement, strongly suggest that the new material is ontogenetically younger than the holotype. The available evidence implies that tooth rows were added during growth in M. grandis. The mandible of M. grandis is distinguished from other moradisaurines in the extreme lingual extension of the tooth plate, which forms a dental shelf or plateau that supports the three lingual-most rows of teeth. In addition, a mentomeckelian bone is preserved, the first to be reported in a Paleozoic reptile. In contrast to the conspicuous wear documented on the teeth of certain other moradisaurines, wear facets are not observed on the teeth of the M. grandis specimens described here. The absence of tooth wear is surprising because the articular morphology of M. grandis is virtually identical to, albeit slightly larger than, that of Labidosaurikos meachami, for which propalinal jaw movement was first inferred in a moradisaurine. A phylogenetic analysis incorporating the new anatomical information confirms the hypothesis that M. grandis forms a clade with Rothianiscus multidontus and Gansurhinus qingtoushanensis within Moradisaurinae, and positions Captorhinikos chozaensis as the basal-most member of the subfamily.
The early evolutionary history of waterfowl (Anseriformes) is poorly understood. Aside from the morphologically aberrant Presbyornithidae, the only other known early Paleogene anseriform taxon is Anatalavis oxfordi from the early Eocene of England. Here, I describe two bones from the late Paleocene of southern Mongolia (localities Naran-Bulag and Tsagaan-Khushuu), which belong to a very large swan-sized swimming waterfowl (Anseriformes) and are described as Naranbulagornis khun, gen. et sp. nov. This is the first non-presbyornithid anseriform bird found in the early Paleogene (Paleocene through early Eocene) of Asia and one of the few currently known Paleocene birds from Central Asia. It is also the largest volant bird from the Paleogene of Asia. Naranbulagornis khun documents a mosaic of autapomorphic and plesiomorphic features that are otherwise present in modern Anhimidae, Anseranatidae, and Anatidae, indicating a greater morphological diversity of early Cenozoic anseriforms than previously thought. The new taxon is morphologically closer to Anatoidea than to Presbyornithidae and represents the earliest global evidence of a spatial coexistence between presbyornithids and other basal waterfowl during the early Paleogene.
In this article, we present the proboscideans from the late Miocene (Turolian) locality Chomateri, Greece, near the classical locality Pikermi. The material consists of juvenile teeth, whose morphological features, such as the dislocation of the half-loph(id)s and the resultant alternate arrangement of the successive loph(id)s (anancoidy), permit assignment to the tetralophodont gomphothere Anancus. However, the anancoidy is rather weak and the occlusal morphology simple, both regarded as primitive features within anancines. Reexamination of the late Miocene anancines from Europe reveals that they all share primitive molar features (weak anancoidy, simple morphology, thick enamel) with the material from Hohenwarth, Austria, showing further primitive skull features, such as the longer mandibular symphysis compared with other anancines. The proper name to refer to the late Miocene anancines from Europe is Anancus lehmanni (Gaziry, 1997), with type locality Dorn-Dürkheim 1 (Turolian; Germany). The presence of Anancus in Chomateri constitutes the first late Miocene record of the genus in Greece, and the first faunal element that clearly indicates that Chomateri postdates the classical Pikermi. Finally, we discuss the biostratigraphy and the biogeography of the late Miocene anancines of the Old World. Anancus originated possibly at ∼9.0–8.5 Ma in Asia and entered Europe during the second half of the Turolian, at ∼7.2 Ma (Tortonian-Messinian boundary). The arrival of Anancus in Europe coincides with a faunal turnover in both the eastern and western sectors of the European Mediterranean region, and in the southern Balkans in particular, with the decline of the ‘Pikermian’ large-mammal fauna.
Triassic-aged fossil vertebrates have been sporadically collected from the Fremouw Formation, central Transantarctic Mountains, since their initial discovery in the late 1960s, giving paleontologists insight into high-latitude faunas in the wake of the end-Permian mass extinction event. On a recent expedition (2010–2011), a small reptile skeleton was collected from Graphite Peak, which we present here alongside novel geological data and interpretations taken on site. Antarctanax shackletoni, gen. et sp. nov., is known from a partial postcranial skeleton including cervical and dorsal vertebrae, a humerus, and both pedes. Important morphological information includes well-defined laminae and deep fossae on cervicodorsal vertebrae. The new taxon can be differentiated from previously known Fremouw Formation reptiles (e.g., Prolacerta, Procolophon), as well as those from the Karoo Basin, South Africa (e.g., Mesosuchus, Proterosuchus, Euparkeria). Our inclusion of A. shackletoni in phylogenetic analyses of early amniotes finds it as an archosauriform archosauromorph, increasing known archosauriform diversity in the Early Triassic. The fauna of the lower Fremouw Formation traditionally has been considered to represent a subset of the Lystrosaurus Assemblage Zone of the Karoo Basin, with differences largely a result of pronounced differences in sampling intensity. However, a review of recent changes to the fauna, as well as a reassessment of occurrences based on older literature, indicates that significant discrepancies, including the co-occurrences of taxa known from both earlier and later in time and the presence of endemic forms in Antarctica, exist between the faunas of the Lystrosaurus Assemblage Zone and lower Fremouw Formation.
Isolated cheek teeth of Sciuridae (Mammalia, Rodentia) from 15 early and middle Miocene localities in Anatolia (Turkey) are described. The localities range in age from local zone B to local zone H, where zones are correlated to European MN zones 1 to 7 + 8. The material represents the two subfamilies: Sciurinae (ground and tree squirrels) and Pteromyinae (flying squirrels). The number of different species found at a single locality ranges from one to four. The Sciurinae were found to belong to the genera Palaeosciurus, Dehmisciurus (formerly called ?Ratufa), Spermophilinus, Tamias, and Atlantoxerus. Members of the Pteromyinae are Hylopetes, Miopetaurista, Aliveria, Albanensia, and Blackia. The MN 2 locality Harami 1 has yielded the oldest Spermophilinus and Miopetaurista known so far. Atlantoxerus adroveri from Bağiçi and Yenieskihisar (MN 7 + 8) is the first member of the Xerini tribe in Anatolia. The squirrel from Keseköy (MN 3), described as Palaeosciurus aff. feignouxi, shows close morphological resemblance to early Miocene Protospermophilus kelloggi from North America. This may suggest that European Palaeosciurus and American Protospermophilus are closely related genera. Three MN 7 + 8 localities (Sarıçay, Bağiçi, and Yenieskihisar) yielded two Spermophilinus species, which shows that Spermophilinus developed, at least locally, along two parallel lines. Similarity between Anatolian and European squirrel assemblages confirms that Anatolia was connected to the European part of the Eurasian continent in early and middle Miocene times. The lacustrine character of the sediments and the presence of both ground and/or tree and flying squirrels indicate that most of the localities represent a wet, but forested environment.
Cavenderichthys talbragarensis (Woodward, 1895) is a common signature freshwater stem teleost in the Upper Jurassic of Australia. Our discovery of numerous otoliths in the Talbragar Fish Bed establishes Cavenderichthys as only the second known Jurassic teleost and the third known stem teleost with otoliths in situ and provides an important calibration point for the interpretation of isolated Mesozoic otoliths. It corroborates the low degree of morphological diversification of stem teleost otoliths. The abundance of otoliths (isolated, in coprolites and in situ) allows the mapping of ontogenetic effects and of intraspecific variability for the first time in attributable stem teleost otoliths. Here, we describe 284 otoliths, mostly from Cavenderichthys. Otoliths in situ in Cavenderichthys document the presence of sagitta, lapillus, and asteriscus. Three other, much rarer otolith types were also found that have a teleost otolith pattern more primitive than that of Leptolepidiformes; the origin of these is unknown, but it is likely that they stem from pholidophoriform fishes of the family Archaeomenidae. If confirmed, this otolith pattern would provide a further highly diagnostic and synapomorphic character to define teleosts at the level of the Leptolepidiformes and above. Different mineral replacement processes in fossils from the Talbragar Fish Bed aided us in finding many otoliths, particularly otoliths in situ. Given their abundance and distinct preservation, it is surprising that otoliths in the Talbragar Fish Bed have not been recognized before.