Search results for "Classification"
showing 10 items of 29475 documents
Globacrochordiceras gen. nov. (Acrochordiceratidae, late Early Triassic) and its significance for stress-induced evolutionary jumps in ammonoid linea…
2013
<i>Globacrochordiceras transpacificum</i> gen. et sp. nov. is an ammonoid (Ammonoidea, Cephalopoda) with a shell characterized by plicate ribbing (rounded and undulating ribs strengthening on the venter without interruption), increasing involution through ontogeny, overhanging and deep umbilical wall, absence of tuberculation, subtriangular whorl section, globose adult shape with a closed umbilicus followed by an abrupt egressive coiling, and a subammonitic adult suture line. This new taxon occurs in Nevada (USA) and in Guangxi (South China). It has its typical occurrence within the <i>Neopopanoceras haugi</i> Zone of late Spathian age (Early Triassic). The plicate r…
Variability of growth pattern observed in Metoposaurus krasiejowensis humeri and its biological meaning
2017
Purpose Histological studies on temnospondyl amphibian bones remain rare. A systematic revision of the histology was applied for the purpose of testing the histovariability in the humeri and becoming new information about the growth pattern. Methods The present study includes 12 humeri of Metoposaurus krasiejowensis, which originate from the Late Triassic clay pit near Krasiejo´w, southwestern Poland. The specimens were scanned with a microCT and the histological thin-sections have been obtained with the standard petrographic method. Results The evaluation of the studied bones shows a uniform growth series resulting in one morphotype. Strikingly, the histological analysis reveals a greater …
Toros-Menalla (Chad, 7 Ma), the earliest hominin-bearing area: how many mammal paleocommunities?
2014
12 pages; International audience; The fossiliferous area of Toros-Menalla (TM) (Djurab Desert, northern Chad) has yielded one of the richest African mammal faunas of the late Miocene. It is also the place where the earliest known hominin, Sahelanthropus tchadensis, was found. Although more than 300 localities are recorded in that area, previous paleoecological studies focused only on the largest and richest one. The integration of the material from other TM localities, and thus of a significant number of mammal taxa, is crucial to improve the corresponding paleoenvironmental reconstructions. Before such inferences can be drawn, it is necessary to test for the ecological integrity of these m…
New data on bat fossils from Middle and Upper Pleistocene localities of France
2011
We describe the bat fossils preserved in four sites from the middle and upper Pleistocene, three of them being well-known French localities: the rock shelter of Les Valerots, the caves of l’Escale at Saint Estève Janson and ‘‘du Prince’’ at Grimaldi (Italy), and the filling of Combe-Grenal, all of them containing microvertebrate assemblages with yet undescribed bat fossils. All species represented in these four localities are still presently distributed in France and had been previously recorded in other Pleistocene localities of central and western Europe, including France. The four assemblages differ both in the abundance of bat fossils as in species composition. The characteristics of ea…
Evidence of endothermy in the extinct macropredatory osteichthyan Xiphactinus audax (Teleostei, Ichthyodectiformes)
2020
Xiphactinus audax is the largest macropredatory osteichthyan ever known (Everhart et al., 2010). Some of the largest specimens exceed 5 m in total length, although the discovery of a few large, isolated teeth suggests that this teleost could reach even larger body sizes (Vavrek et al., 2016, and references therein). Fossil remains of this species have only been reported from the Upper Cretaceous of North America, across the Western Interior Basin (Schwimmer et al., 1997; Vavrek et al., 2016). The discovery of several virtually complete individuals in this area has provided valuable information about the anatomy, the dimensions, and the ecology of this species (Cope, 1872; Bardack, 1965). Xi…
Nomenclatural revision concerning some genera of the Order Trigoniida (Bivalvia)
2018
The authors have become aware of a couple of nomenclatural conflicts involving Mesozoic trigoniid genera, which are in need of clarification and proposal of replacement names: The case of Protrigonia. The subgenus Trigonia (Protrigonia) Guo, 1985 (p. 204, 269; type species Trigonia (Protrigonia) yunnanensis Guo, 1985), was proposed to encompass those species referred to the genus Trigonia which, according to that author, have small and nearly smooth shells and relatively weak teeth. Guo (1985) also included other Triassic species: Trigonia gaytani (von Klipstein, 1843) and Trigonia zlambachiensis Haas, 1909. According to Fang et al. (2009, p. 55) there was a wrong translation from the Chine…
Le site à ambre et plantes du Cénomanien de Neau (Mayenne, France)
2020
International audience; A new Cenomanian amber- and plant-bearing deposit has been discovered at Neau, in the Mayenne department (France). The Cenomanian fossiliferous lignites are located in karst filling in a substratum of Cambrian limestones. The amber corresponds mainly to tiny millimetric grains, devoid of arthropod inclusions, but rich in microorganisms, especially the sheated bacteria Leptotrichites resinatus , and containing pollen grains ( Classopollis ) and wood fibers (Araucariacae or Cheirolepidiaceae). The lignites provide abundant conifer and ginkgoale cuticle fragments ( Frenelopsis , Eretmophyllum ) and a lot of palynomorphs ( e.g. Gleicheniidites senonicu s, Cyathidites , D…
Evolutionary trends of Triassic ammonoids.
2015
The Triassic represents a key interval in the evolutionary history of ammonoids. Characterized by the dominance of the Ceratitida with their typical suture line indented on the lobes only, the Triassic quasi-monophyletic clade shows a remarkable biostratigraphic and geographic record. However, very few studies have thoroughly investigated their evolutionary trends, except for taxonomic richness. Although Triassic ammonoids show a very large range of morphologies, suture complexity and adult size, little is currently known about their trends, except for peculiar time intervals or taxonomic groups. Nevertheless, it seems that taxonomic diversity and morphological disparity of Triassic ammonoi…
Messinian Italian Bovidae revised: paleobiogeographic and biochronological implications
2021
Bovidae from the Messinian localities of Italian Peninsula are poorly known and documented except in the Monticino Quarry record (Brisighella, central Italy), which represents, therefore, a key loc...
Early Miocene marsupialiforms, gymnures, and hedgehogs from Ribesalbes-Alcora Basin (Spain)
2020
AbstractMaterials from the localities of Araia d'Alcora in the Ribesalbes-Alcora Basin (Spain, early Miocene, Biozone C, MN4) have yielded an assemblage of erinaceids and metatherians, relatively rich for an Iberian site. The most common erinaceid is the gymnureGalerix symeonidisiDoukas, 1986, present in almost all of the studied sites. Other erinaceids in the faunal list are possibly an indeterminate species of the generaLantanotheriumFilhol, 1888 andAtelerixPomel, 1848, in what constitutes one of their oldest occurrences in Europe. Metatherians are represented by the herpetotheriidAmphiperatherium frequens erkertshofense(Koenigswald, 1970). The material described here was partially publis…