Search results for "Axon"
showing 10 items of 2126 documents
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…
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…
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…
Revision of Permo-Carboniferous griffenflies (Insecta: Odonatoptera: Meganisoptera) based upon new species and redescription of selected poorly known…
2009
33 pages; International audience
Athenacrinus n. gen. and other early echinoderm taxa inform crinoid origin and arm evolution
2020
AbstractIntermediate morphologies of a new fossil crinoid shed light on the pathway by which crinoids acquired their distinctive arms. Apomorphies originating deep in echinoderm history among early nonblastozoan pentaradiate echinoderms distinguish Tremadocian (earliest Ordovician) crinoid arms from later taxa. The brachial series is separated from the ambulacra, part of the axial skeleton, by lateral plate fields. Cover plates are arrayed in two tiers, and floor plates expressed podial basins and pores. Later during the Early Ordovician, floor plates contacted and nestled into brachials, then were unexpressed as stereom elements entirely and cover plates were reduced to a single tier. Inco…
Dental microwear texture reflects dietary tendencies in extant Lepidosauria despite their limited use of oral food processing
2019
Lepidosauria show a large diversity in dietary adaptations, both among extant and extinct tetrapods. Unlike mammals, Lepidosauria do not engage in sophisticated mastication of their food and most species have continuous tooth replacement, further reducing the wear of individual teeth. However, dietary tendency estimation of extinct lepidosaurs usually rely on tooth shape and body size, which allows only for broad distinction between faunivores and herbivores. Microscopic wear features on teeth have long been successfully applied to reconstruct the diet of mammals and allow for subtle discrimination of feeding strategies and food abrasiveness. Here, we present, to our knowledge, the first de…
Urania sloanus (Cramer, 1779) (Lepidoptera: Uraniidae), an Enigmatic Extinct Species in Polish Museum Collections
2019
Urania sloanus is an endemic species in Jamaica. The species probably became extinct at the end of the 19th century or the beginning of the 20th century. During the work on combining the collections of exotic butterflies in the Upper Silesian Museum in Bytom, one specimen of this taxon was found. The discovery of this species in the Museum of Upper Silesia in Bytom led us to search for entomological collections in other Polish museums. As a result of our search, we found three additional specimens: two specimens in the collection of the Museum of Natural History of the University of Wrocław and one at the Zoological Museum of the Polish Academy of Sciences in Warsaw. In total, in the Polish…
Systematic Position of Gastropini (Diptera: Ephydridae), and a Review of Two Included Genera:GastropsWilliston andNotacanthinaMacquart
2017
The placement of the tribe Gastropini within the subfamily Gymnomyzinae, with the tribe Gymnomyzini as a sister-group, is supported. Validity for two genera Gastrops Williston and Notacanthina Macquart (senior synonym of Beckeriella Williston) is maintained. Particular characters of their proboscis, ventral receptacle and the male terminalia are presented. A key to species and habitus photographs of selected species of Gastrops and Notacanthina are provided. The following new combinations are proposed: Notacanthina clypeata (Lizarralde de Grosso, 1986), comb. nov., N. fasciata (Mathis & Grimaldi, 2000), comb. nov., N. filipina (Lizarralde de Grosso, 1994), comb. nov., N. gigas (Lizarralde d…
Use of DNA barcoding in the assignment of commercially valuable fish species from Romania
2017
DNA barcoding is a molecular technique frequently used either for biodiversity monitoring and fish conservation or in the identification of the species of origin for raw and processed food from restaurants or fish markets. The most important aspect of this technique is that it works for all stages of life and can be used to distinguish between closely related taxa. Also, the technique has been used to unmask attempts of frauds in fish markets where more desirable and expensive fish are sometimes substituted with lower valued species. Our study aims to test the utility of the COI barcoding gene in the correct identification of several economically and ecologically valuable fish species, and …
Behavioural, ecological, and evolutionary aspects of diversity in frog colour patterns
2016
The role of colours and colour patterns in behavioural ecology has been extensively studied in a variety of contexts and taxa, while almost overlooked in many others. For decades anurans have been the focus of research on acoustic signalling due to the prominence of vocalisations in their communication. Much less attention has been paid to the enormous diversity of colours, colour patterns, and other types of putative visual signals exhibited by frogs. With the exception of some anecdotal observations and studies, the link between colour patterns and the behavioural and evolutionary ecology of anurans had not been addressed until approximately two decades ago. Since then, there has been eve…