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München, Germany

Nutzel A.,GeoBio Center | Nakazawa K.,28 2 Koyama Shimouchikawara cho
Journal of Systematic Palaeontology

A gastropod fauna from the Permian (Capitanian) Akasaka Limestone from Japan is described. It is one of the most diverse known Permian gastropod faunas and consists of at least 74 species level taxa. Forty taxa have been identified to species level; the remainder are treated in open nomenclature because of insufficient preservation. In addition, three types of neritimorph opercula are present. One family, seven genera and 28 species are described as new by N̈utzel. New taxa are the family Araeonematidae, the genera Coeloconulus, Asamiella, Costataenia, Akasakiella, Cerithiozone, Yochelsonistylus and Permocerithium, and the species Anomphalus japonicus, Anematina parva, Araeonema panthalassica, Coeloconulus panae, Trochonodus permianus, Goniasma fortecarinata, G.? nodifera, Vebericochlis mazaevi, Costataenia hayasakai, Trypanocochlea parva, Cerithiozone ornata, Cerithioides angulatum, Stegocoelia akasakaensis, Yochelsonistylus seussae, Y. felixi, Knightella hydrobiformis, Palaeostylus? irregularis, P. attenuatus, P. minutus, P. lateapicatus, Permocerithium nudum, Protorcula permiana, Medfrazyga convexa, M. rectecostata, Acteonina koizumii, Heterosubulites fusiformis, Nanochilina japonica and Streptacis orientalis. The gastropod fauna of the Akasaka Limestone has previously been known for containing some of the largest species from the Permian and the entire Palaeozoic, with specimens as large as 40 cm. The fauna is strongly dominated by molluscs and especially by gastropods and bivalves. The dominance of these groups represents a modern aspect of this fauna. Among the gastropods, high-spired caenogastropods form the most diverse and abundant group. Most of the new gastropod genera are related to Cerithioidea and some have anterior siphonal canals. This suggests an early radiation of these caenogastropods in the Asia/Panthalassa realm. The relatively large number of new taxa suggests that gastropod faunas of this region have been poorly sampled or preservation of such faunas is only sporadic. Several of the present genera and a few species are also known from Permian deposits in China, Malaysia, and Vietnam. Some of the genera are cosmopolitan. © 2012 The Natural History Museum. Source

Aiglstorfer M.,University of Tubingen | Aiglstorfer M.,Senckenberg Center for Human Evolution and Palaeoenvironment | Rossner G.E.,SNSB Bayerische Staatssammlung fur Palaontologie und Geologie | Rossner G.E.,Ludwig Maximilians University of Munich | And 3 more authors.
Palaeobiodiversity and Palaeoenvironments

One of the rare records of a rich ruminant fauna of late Middle Miocene age (Sarmatian sensu stricto; 12.2-12.0 Ma) was discovered at the Gratkorn locality (Styria, Austria). It comprises, besides Micromeryx flourensianus, ?Hispanomeryx sp., Euprox furcatus, Palaeomerycidae gen. et sp. indet., and Tethytragus sp., one of the oldest records of Dorcatherium naui. Gratkorn specimens of the latter species are in metric and morphologic accordance (e.g. Selenodont teeth, bicuspid p2, non-fusion of malleolus lateralis and tibia) with type material from Eppelsheim (Germany) and conspecific material from Atzelsdorf (Austria), and do not show an intermediate morphology between Late Miocene Dorcatherium naui and Middle Miocene Dorcatherium crassum, thus enforcing the clear separation of the two species. It furthermore confirms the assignation of Dorcatherium naui to a selenodont lineage (together with Dorcatherium guntianum) distinct from a bunoselenodont lineage (including Dorcatherium crassum). The record of ?Hispanomeryx sp. is the first of this genus in Central Europe. While Tethytragus sp. could also be a new bovid representative for the Sarmatian of Central Europe, Micromeryx flourensianus and Euprox furcatus are well-known taxa in the Middle Miocene of Central Europe, but comprise their first records from Styria. Morphological data from this work in combination with isotopic measurements (δ18OCO3, δ13C; Aiglstorfer et al. 2014a, this issue) indicate a niche partitioning for the ruminants from Gratkorn with subcanopy browsing (Euprox furcatus), top canopy browsing (Tethytragus sp.) and even a certain amount of frugivory (Dorcatherium naui and Micromeryx flourensianus). © 2014 Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg. Source

Nutzel A.,GeoBio Center

The shell of marine gastropods conserves and reflects early ontogeny, including embryonic and larval stages, to a high degree when compared with other marine invertebrates. Planktotrophic larval development is indicated by a small embryonic shell (size is also related to systematic placement) with little yolk followed by a multiwhorled shell formed by a free-swimming veliger larva. Basal gastropod clades (e.g. Vetigastropoda) lack planktotrophic larval development. The great majority of Late Palaeozoic and Mesozoic 'derived' marine gastropods (Neritimorpha, Caenogastropoda and Heterobranchia) with known protoconch had planktotrophic larval development. Dimensions of internal moulds of protoconchs suggest that planktotrophic larval development was largely absent in the Cambrian and evolved at the Cambrian-Ordovician transition, mainly due to increasing benthic predation. The evolution of planktotrophic larval development offered advantages and opportunities such as more effective dispersal, enhanced gene flow between populations and prevention of inbreeding. Early gastropod larval shells were openly coiled and weakly sculptured. During the Mid- and Late Palaeozoic, modern tightly coiled larval shells (commonly with strong sculpture) evolved due to increasing predation pressure in the plankton. The presence of numerous Late Palaeozoic and Triassic gastropod species with planktotrophic larval development suggests sufficient primary production although direct evidence for phytoplankton is scarce in this period. Contrary to previous suggestions, it seems unlikely that the end-Permian mass extinction selected against species with planktotrophic larval development. The molluscan classes with highest species diversity (Gastropoda and Bivalvia) are those which may have planktotrophic larval development. Extremely high diversity in such groups as Caenogastropoda or eulamellibranch bivalves is the result of high phylogenetic activity and is associated with the presence of planktotrophic veliger larvae in many members of these groups, although causality has not been shown yet. A new gastropod species and genus, Anachronistella peterwagneri, is described from the Late Triassic Cassian Formation; it is the first known Triassic gastropod with an openly coiled larval shell. © The Palaeontological Association. Source

Clauss M.,University of Zurich | Rossner G.E.,SNSB Bayerische Staatssammlung fur Palaontologie und Geologie | Rossner G.E.,Ludwig Maximilians University of Munich | Rossner G.E.,GeoBio Center
Annales Zoologici Fennici

The omasum of pecoran ruminants (which is absent in tragulids) and shorter gestation periods in non-giraffid crown pecorans (as opposed to giraffids) could represent cases of key innovations that caused disparity in species diversity in extant ruminants. Literature suggests that the different ruminant groups inhabited similar niche spectra at different times, supporting the 'increased fitness' interpretation where a key innovation does not mainly open new niches, but allows more efficient use of existing ones. In this respect, we explored data on fossil species diversity of Afro-Eurasian ruminants from the Neogene and Quaternary. Tragulid and giraffid diversity first increased during the Early/Middle Miocene with subsequent declines, whereas bovid and cervid diversity increased distinctively. Our resulting narrative, combining digestive physiology, life history and the fossil record, thus provides an explanation for the sequence of diversity patterns in Old-World ruminants. © Finnish Zoological and Botanical Publishing Board 2014. © 2014 Finnish Zoological and Botanical Publishing Board. Source

Kocha A.,Leibniz Institute for Biodiversity of Animals | Gaulke M.,GeoBio Center | Bohme W.,Leibniz Institute for Biodiversity of Animals

Recently, the first part of the morphological revision of the Southeast Asian water monitor lizards of the Varanus salvator (Laurenti, 1768) species group provided a taxonomic overview over the members of this successful and widespread species complex (Koch et al. 2007). There, the Philippine taxa marmoratus, nuchalis and cumingi were reelevated to species status due to diagnostic morphological characteristics, e.g. significantly enlarged scales on the neck region. In this second part of the ongoing revision, these three species are re-investigated using additional voucher specimens and advanced statistical techniques including canonical variates analysis and principal component analysis. Our new investigations indicate that V. marmoratus represents a composite species, comprising at least three distinct taxa. Hence, the populations of the Sulu Archipelago (Tawi-Tawi Island) and those of the Palawan region are described as new species, viz. Varanus rasmusseni sp. nov. and V. palawanensis sp. nov., respectively. The allopatric island populations of V. cumingi inhabiting Samar, Leyte, and Bohol (the East Visayan subregion) show characteristic and geographically correlated colour patterns distinct from the type locality Mindanao (the second subregion of Greater Mindanao), warranting subspecific partition of this species. The new subspecies is named V. cumingi samarensis ssp. nov. In contrast, the taxonomic status of V. nuchalis remained unchanged, although this species shows some considerable variation in colour pattern. The systematic chapters are supplemented with notes about biology and conservation status. The hitherto underestimated diversity and zoogeography of Philippine water monitors is discussed in the light of Pleistocene sea level fluctuations. Finally, we introduce a scenario for the evolution and spread of Southeast Asian water monitor lizards and provide an identification key for the Philippine members of the V. salvator complex. Copyright © 2010 • Magnolia Press. Source

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