Postcranial remains of Baphetes and their bearing on the relationships of the Baphetidae (= Loxommatidae)

The first unequivocal postcranial remains of baphetids (= loxommatids) associated with skull roof and lower jaw material are reported from a specimen of Baphetes from the English Upper Carboniferous, Duckmantian. Characters of the mandible, including the incorporation in the symphysis of paired parasymphysial plates, permit the identification of a previously indeterminate jaw from the Langsettian (Westphalian A) of Nova Scotia, as baphetid. The postcranial remains include vertebrae, pectoral and pelvic limb and limb girdle elements that present a combination of unique characters extending the diagnosis of the family Baphetidae, together with plesiomophic and derived characters which suggest that baphetids are primitive stem group tetrapods.     

Functional morphology of the forelimb of tupaiids (Mammalia, Scandentia) and its phylogenetic implications

In this study, the forelimb of 12 species of tupaiids was analyzed functionally and compared to that of other archontan mammals. Several differences that relate to differential substrate use were found in the forelimb morphology of tupaiids. These differences included shape of the scapula, length and orientation of the coracoid process, size of the lesser tuberosity, shape of the capitulum, length of the olecranon process, and shape of the radial head and central fossa. The forelimb of the arboreal Ptilocercus lowii, the only ptilocercine, is better adapted for arboreal locomotion, while that of tupaiines is better adapted for terrestrial (or scansorial) locomotion. While the forelimb of the arboreal Ptilocercus appears to be habitually flexed and exhibits more mobility in its joints, a necessity for movement on uneven, discontinuous arboreal supports, all tupaiines are characterized by more extended forelimbs and less mobility in their joints. These restricted joints limit movements more to the parasagittal plane, which increases the efficiency of locomotion on a more even and continuous surface like the ground. Even the most arboreal tupaiines remain similar to their terrestrial relatives in their forelimb morphology, which probably reflects the terrestrial ancestry of Tupaiinae (but not Tupaiidae). The forelimb of Urogale everetti is unique among tupaiines in that it exhibits adaptations for scratch-digging. Several features of the tupaiid forelimb reflect the arboreal ancestry of Tupaiidae and it is proposed that the ancestral tupaiid was arboreal like Ptilocercus. Also, compared to the forelimb character states of tupaiines, those of Ptilocercus are more similar to those of other archontans and it is proposed that the attributes of the forelimb of Ptilocercus are primitive for the Tupaiidae. Hence, Ptilocercus should be considered in any phylogenetic analysis that includes Scandentia.     

The marine diapsid reptile Endennasaurus from the Upper Triassic of Italy

Abstract:  The marine reptile Endennasaurus from the Upper Triassic Zorzino Limestone of northern Italy is redescribed and reassessed. New details of the skull and postcranial skeleton are revealed, confirming the attribution of this genus to the diapsid reptile clade Thalattosauriformes. Phylogenetic analysis suggests that Endennasaurus was related to the European genus Askeptosaurus and the Chinese Anshunsaurus . Despite a rather conservative postcranial morphology, Endennasaurus clearly occupied a highly specialized dietary niche as it combined a slender tapering premaxillary rostrum with a complete absence of either marginal or palatal teeth.     

A new lizard-like reptile (Diapsida: Lepidosauromorpha) from the Middle Jurassic of England

The Middle Jurassic (Late Bathonian) Mammal Bed at Kirtlington, Oxfordshire, has yielded a rich assemblage of small vertebrates including mammals, frogs, salamanders and small reptiles. This paper describes the skull of a new diapsid reptile, Marmorelta oxoniensis, which was common within the fauna. The skull is gracile with large orbits and relatively long external nares. The frontals and parietals are single in the adult and almost separated on the roof of the skull by the postfrontals. The temporal region shows a mosaic of primitive and derived character states. The quadrate was firmly held to the skull by a large squamosal and a small, free, quadratojugal was retained. However, reduction of the anterior process of the quadratojugal and of the posterior process of the jugal left the lower temporal fenestra broadly open. Comparison with other diapsids leads to the conclusion that Marmoretta was a lepidosauromorph, most probably the sister taxon of Lepidosauria.     

Heterochrony and tooth evolution in hyperodapedontine rhynchosaurs (Reptilia, Diapsida)

The tooth arrangement of hyperodapedontine rhynchosaurs shows clear patterns of morphological derivation, which can be summarized as three main apomorphic trends: the increase in the number of tooth rows lateral to the main maxillary groove, the loss of dental structures (medial groove and lingual teeth) medial to the main maxillary groove, and the loss of dental structures (medial crest and lingual teeth) medial to the main dentary crest. The analysis of these trends from a heterochronic viewpoint reveals that acceleration was the most probable process involved in the increase in number of the lateral maxillary tooth rows, while the loss of the medial structures of the maxilla and dentary seem to be related respectively to neoteny and post-displacement. Both peramorphic and paedomorphic processes are, therefore, thought to have directed the main modifications seen in the tooth arrangement of the hyperodapedontine rhynchosaurs. Heterochrony plays an important role in the evolution of the Late Triassic rhynchosaurs, which are differentiated mainly on the basis of their dental morphology.     

The species taxonomy of the sauropodomorph dinosaurs from the Löwenstein Formation (Norian, Late Triassic) of Germany

The species taxonomy of the sauropodomorph dinosaurs from the Löwenstein Formation of Germany is examined. Previous work has classified these into two taxa: Sellosaurus gracilis from a number of localities and the widespread Plateosaurus engelhardti from a single monospecific accumulation in the Löwenstein Formation, near the town of Trossingen. The current hypodigm of Sellosaurus gracilis is found to contain a substantial amount of variation. This includes differences in the dentition, structure of the skull, composition of the sacrum and the structure of the caudal vertebrae and pelvis. This variation was analysed using a specimen–based parsimony analysis of the sauropodomorphs from the Löwenstein Formation. It was found that two discrete taxa comprise the current hypodigm of Sellosaurus . The more common of these two is a plesiomorphic form for which the correct name is Efraasia minor comb. nov. The less common form (which includes the holotype of Sellosaurus gracilis ) is found to share a number of synapomorphies with Plateosaurus engelhardti and is placed in this genus as Plateosaurus gracilis     

Late Paleozoic and Triassic bryozoans from the Tethys Himalaya (N India, Nepal and S Tibet)

New findings of Late Paleozoic and Triassic bryozoans from the Tethys Himalaya are reported. Fifteen species, including three undetermined, were described, while determinations at order, family or genus level were obtained on fragmentary material. The studied bryozoans were framed in a solid lithostratigraphic scheme spanning across the Tethys Himalaya for over 1500 km, from NW India (Zanskar and Spiti) through Nepal (Dolpo and Manang) to South Tibet; they are concentrated in correlatable stratigraphic intervals corresponding to the Upper Devonian-Tournaisian, Bashkirian, Sakmarian, Midian and Lower Norian. This study allowed us to integrate bryozoan occurrences reported from the literature, mostly referring to the Tournaisian, Bashkirian and Early Norian, and to refine the available biostratigraphic dates. Bryozoan-rich intervals are interpreted as associated to long-term transgressions, in turn driven by major climatic and/or tectonic events. Cosmopolitan genera which prevail in the Paleozoic, are replaced by provincial forms after the Triassic crisis.     

Liverwort fossils from the Late Triassic of Baiyin City,Gansu Province,and their geological significance

Although liverworts are widely distributed around the world with a large number of extant species, reliable fossil records are relatively rare. Here, we report a new species, Ricciopsis baojishanensis Han and Yan, n. sp. (Ricciaceae) and an unnamed species, Hepaticites sp. from the Late Triassic Nanying’er Formation in Baojishan Basin, Baiyin City, Gansu Province, Northwest China. The generic designation is based on detailed comparison of the gross morphology with related fossil and extant species. The new species is characterized by its rosette-forming thallus, dichotomous branching, ribbon-like segments and entire margins. The current fossils represent the first record of liverwort from the Late Triassic in Baojishan Basin, Gansu Province. Based on the different fossil records of the Ricciaceae, we suggest that these taxa were widely distributed during Late Triassic to Oligocene worldwide, mainly in warm temperate and tropical environments, similar with their current distribution. The discovery of the present fossils indicates that the climate of Baojishan Basin in Late Triassic is warmer and more humid than that of today.     

First report of dinosaurian claws from the Late Triassic of India

The Late Triassic Tiki Formation has yielded five isolated nearly complete claws or ungual phalanges from a fossil locality, which are described in detail and compared with other Late Triassic tetrapods. Of these, four ungual phalanges are slender, asymmetric, ventrally recurved, transversely compressed, and contain deep collateral grooves on either side, a low median keel on the proximal articular surface and a prominent proximoventral flexor tubercle showing their high similarity to the theropod dinosaurs. The remaining claw is unlike that of any theropods in terms of high robusticity and near symmetry. However, as in dinosaurs it is ventrally recurved and contains deep lateral grooves, a small flexor tubercle, lateromedially extended proximal articular surface with a distinct median keel and is considered as belonging to an indeterminate dinosaur. Although it is not possible to ascertain whether the unguals belong to a single taxon or multiple taxa, this new find points towards the presence of small dinosaurs in the Late Triassic Tiki fauna.     

Plants of Leptostrobus Heer （Czekanowskiales） from the Early Cretaceous and Late Triassic of China, with Discussion of the Genus

Investigation of the Mesozoic seed plant Leptostrobus Heer from the Yangcaogou Formation of the Late Triassic and the Yixian Formation of the Early Cretaceous, Liaoning Province, China, provides new Insight Into Its general morphology and geographical distribution. The materials of L. cancer from the Yixian Formation described herein are later than all the past findings of this species and add to the record of L. cancer during the Early Cretaceous. Based on well-preserved specimens, the specific diagnosis Is slightly emended and the reconstructlon of L. cancer Is perfected. The materials from the Yangcaogou Formation of the Late Triassic are placed in L. spheericus, in addition, we review the history of investigation of the genus Leptostrobus since its establishment in 1876 and discuss the main characteristics of each species.     

New Late Triassic gastropods from the wallowa Terrane (Idaho) and their biogeographic significance

Summary Two characteristic new species and one new genus are described from the Late Triassic of Idaho (Wallowa Terrane):Brochidiella idahoensis n. gen., n. sp. andPtychostoma ornata n. sp.Brochidiella is only known from western North America.Ptychostoma is present in the Carnian of the European Alps (Tethys) and is widespread in the western part of the North American continent (Panthalassa). Late Triassic gastropod faunas from the accreted terranes of North America are poorly known but hold a great potential for future palaeobiogeographic reconstructions.     

Some Late Triassic gastropods from the Nayband formation in Central Iran

Summary Six gastropod species from the Late Triassic Nayband Formation are reported. The following taxa are introduced as new:Trochonodus iranicus n. gen., n. sp. andCryptaulax convexa n. sp. The following species are transferred toTrochonodus n. gen.:Riselloidea aliabadensis Nützel and Senowbari-Daryan 1999 (type species ofTrochonodus),Riselloidea biarmata (Münster),Riselloidea bitorquata (Hébert and Eudes-Deslongchamps),Scalaria limatula Ammon, andAmberleya trimonilis (Orbigny). The holotype ofChulitnacula jenningsi (Douglas) is newly illustrated and described. According to the current state of knowledge, the gastropod faunas of the Nayband Formation near Esfahan and near Tabas differ considerably from each other. They share onlyAnulifera binodosa. TheAnulifera species-cluster has representatives in the Norian/Rhaetian from the North Alps, Iran, Burma, and South China. Contribution to the Triassic Paleontology of Iran No. 10. For No. 9 see previous text in this volume.     

The trackmaker of Apatopus (Late Triassic, North America): implications for the evolution of archosaur stance and gait

Abstract:  For some decades, a major focus of research has been on how locomotor modes changed in some archosaurian reptiles from a more or less 'sprawling' to an 'erect' posture, whether there were discrete intermediate stages, and how many times 'erect' posture evolved. The classic paradigm for the evolution of stance and gait in archosaurs, a three-stage transition from sprawling to 'semi-erect' to erect posture, has been replaced by a subtler understanding of a continuum of changing limb joint angles. We suggest a further separation of terminology related to stance vs. gait so as not to entail different processes: 'sprawling' and 'erect' should refer to continua of stance; 'rotatory' and 'parasagittal' are more appropriate ends of a continuum that describes the motions of gait. We show that the Triassic trackway Apatopus best fits the anatomy and proportions of phytosaurs, based on a new reconstruction of their foot skeleton; it is less likely to have been made by another pseudosuchian or non-archosaurian archosauromorph. Moreover, the trackmaker was performing the high walk. A phytosaurian trackmaker would imply that the common ancestor of pseudosuchians, and therefore archosaurs could approximate the high walk (depending on phylogeny), and if so, erect stance and parasagittal gait did not evolve independently in pseudosuchians and ornithosuchians, although the kinematic mechanisms differed in the two groups. It remains to be seen how far outside Archosauria, if at all, more or less erect posture and parasagittal gait may have evolved.     

Skeletal indicators of ecological specialization in pika (Mammalia,Ochotonidae)

Pika species generally fall into two ecotypes, meadow‐dwelling (burrowing) or talus‐dwelling, a classification that distinguishes a suite of different ecological, behavioral, and life history traits. Despite these differences, little morphological variation has previously been documented to distinguish among ecotypes. The aim of this study was to test whether postcranial features related to burrowing are present in meadow‐dwelling species and whether talus‐dwelling species exhibit postcranial modifications related to frequent leaping between rocks. To test this, the scapula, humerus, ulna, radius, innominate, femur, tibia, and calcaneus of 15 species were studied and measured. Twenty‐three measurements were taken on 199 skeletons, and 19 indices were constructed from these measurements. Indices were compared between the two ecotypes using Student's t‐test. Comparisons among ecotypes, species, and subgenera were made using one‐way ANOVA with the Tukey honest significant difference post hoc test. Multivariate results were generated using principal components analyses. Thirteen forelimb and hind limb indices proved significant in distinguishing the meadow‐dwelling, talus‐dwelling, and intermediate forms. A number of these indices are associated with burrowing or leaping in other mammals, providing some support for the hypothesis that postcranial modifications in pika are related to locomotor differences. This evidence of morphological responses to ecological specialization will be useful for reconstructing the paleobiology of extinct taxa, assessing the behavioral variability of extant species, and improving our understanding of the evolutionary history of pikas. J. Morphol., 2013. © 2013 Wiley Periodicals, Inc.     

Late Triassic (Late Norian) gastropods from the Wallowa Terrane (Idaho,USA)

A diverse Late Triassic (Late Norian) gastropod fauna is described from the Mission Creek Limestone of the Wallowa terrane (Idaho, USA). Sample standardization by rarefaction analysis indicates that the fauna is even more diverse than the Late Triassic gastropod fauna from the Pucara Formation (Peru) which represents the most diverse gastropod fauna from South America. The gastropod fauna consists of 66 species; several genera are reported for the first time from North America. A high percentage of the species are highly ornamented and several have distinct siphonal canals. This suggests that the appearance of truly Mesozoic elements among the gastropods began before the Mesozoic Marine Revolution in other clades. The fauna is dominated by high-spired strongly ornamented procerithiids, a group more characteristic for the Jurassic. Comparison of the present fauna and the Iranian Nayband Formation gastropod fauna show that the procerithiids underwent a first global radiation in the Late Triassic. The high number of new species in this fauna suggests that sampling of Late Triassic gastropod faunas is still incomplete and hinders palaeobiogeographic considerations. Previous suggesions that gastropod faunas from the Wallowa and Wrangellia terranes resemble each other and are distinct from those of Alexander, Chulitna, and Farewell terranes are basically corroborated. The gastropod fauna of the Mission Creek Limestone differs considerably from that of the western and central Tethys but shares several taxa with the Late Triassic gastropod fauna of the Pucara Formation in Peru. Thus, the Hispanic corridor was probably not present in the Norian but opened only in the Early Jurassic. The subfamily Andangulariinae is introduced and placed in the Zygopleuridae. The generaSpiniomphalus, Nodoconus, Gudrunella, Blodgettella, Idahospira, andSiphonilda and the subgenusCryptaulax (Wallowax) are introduced. 27 species are erected. A lectotype is designated forCryptaulax rhabdocolpoides Haas, 1953.      

Trace fossils in fluvial deposits of the uppermost Stockton Formation (Late Triassic), Newark Basin,New Jersey

Abstract

Fluvial deposits of the uppermost Stockton Formation (Late Triassic), Newark Basin, west-central New Jersey have yielded an assemblage of trace fossils. Dominated by burrows, specimens include Cochlichnus anguineus, Helminthoidichnites tenuis, Planolites beverleyensis, Scoyenia gracilis, Spongeliomorpha carlsbergi, Treptichnus bifurcus, Treptichnus pollardi, plant remains, and an undetermined vertebrate trace fossil. The assemblage belongs to the Scoyenia ichnofacies. On the basis of stratification and primary sedimentary structures, the beds are interpreted as deposits in a meandering stream environment. Larval insects, wormlike forms, and arthropods are probably responsible for most of the animal traces in wet or moist channel, floodplain, and point bar sediments subject to subaerial exposure.