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Elasmobranch (Chondrichthyes: Elasmobranchii) faunal complex from Late Albian (Early Cretaceous) of Kanev dislocations, Ukraine

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Abstract

During Albian stage of Early Cretaceous cartilaginous fish experienced a rapid diversification event that lead to the exploitation of ecological niches previously unoccupied by them. There are few locations in the world where marine vertebrate complexes of this age can be studied. Sampling from six thin layers of quartz-glauconite sands in Kanev dislocations, Ukraine yielded more than three thousand vertebrate specimens, including elasmobranch teeth, chimaera dental plates, fish and sauropsid teeth and bones. Our study represents the first illustrated and detailed description of elasmobranch teeth from Ukrainian Albian deposits since Rogovich, 1860 monograph. Rogovich described several new species from this location and we got a chance to include in this work some of his specimens currently housed in the National Natural History Museum of National Academy of Sciences of Ukraine. This lead to resurrection of some of his species names, notably Polyacrodus bidentatus, Synechodus kessleri, Heterodontus minutus and Archaeolamna striata. In addition, our research provides insight into the systematics of Albian species of Synechodus and Heterodontus, specifically S. nitidus and S. tenuis validity and H. upnikensis dental morphology. Studied complex, consisting of both our and Rogovich specimens, includes a typical benthic species group of synechodontiform, bullhead, angel, carpet and dogfish sharks. Strangely, batoid and hybodont finds are very rare, Meristodonoides teeth are present only in one layer of sands while lamniform sharks are the most common shark taxon. Lamniformes in Kanev Albian displays the highest ecological diversity, with small sand tiger shark species, early pseudoscapanorhynchids and large carnivorous sharks Cretoxyrhina and Cretolamna. Most importantly, Paraisurus and Cretoxyrhina vraconensis findings confirm Late Albian age of these deposits since they are usually described in geological literature non-specifically as Albian-Cenomanian.

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The nominal Eucrossorhinus microcuspidatus and Cretorectolobus olsoni from the Campanian Judith River Formation of Montana, correspond to teeth from juvenile and adult individuals of one single species of orectoloboid shark. The type series of the latter is heterogeneous and includes, besides the holotype, a tooth belonging to a different orectoloboid of a new generic type named Cederstroemia. This genus is unique among Orectolobiformes by comprising sharks with dental adaptations towards a strict cutting dentition. Two new species of Cederstroemia are described. -Author
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The uppermost beds of the Alinga Formation and the basal part of the overlying Beedagong Claystone in the lower Murchison River area at the southern end of the Southern Carnarvon Basin, Western Australia, have yielded 15 species of lamniform sharks referred to ten genera, of which one genus and three species are new: Cretoxyrhina mantelli, Archaeolamna aff. kopingensis, A. haigi sp. nov., Leptostyrax sp., Cretolamna appendiculata, C. gunsoni sp. nov., Pseudoisurus tomosus, Pseudoisurusl sp., Paranomotodon sp., 'Anomotodon' sp., Johnlongia allocotodon gen. et sp. nov., Carcharias sp. A, C. sp. B, Squalicorax ex gr. curvatus, and S. volgensis. Direct correlation with Germany and the Saratov Province of the Russian Platform, using cosmopolitan lamnoids, dates the basal part of the Beedagong Claystone in the studied area as early or mid Cenomanian. The top of the Alinga Formation is provisionally placed in the early Cenomanian. This contrasts with the most recent previous estimate which suggested an early Turonian age for the upper half of the Alinga Formation. The present account is the first comprehensive documentation of Cretaceous selachians from Australia. It demonstrates the great potential of the use of lamniform shark teeth in intercontinental correlation of mid Cretaceous marine deposits.
Article
Four years after joining the Natural History Department of the British Museum in 1882, Arthur Smith Woodward published his first taxonomic paper erecting three new species based on sharks’ teeth. He retired from the Natural History Museum in 1924 but continued to publish until his death in 1944 at the age of 80. In total he named 321 new fossil fishes, a remarkable achievement, marking him out as the most influential palaeoichthyologist of his time. For the first time brief details of all his type specimens are brought together, accompanied in many cases by high-quality photographic images, in an online format readily available to anyone with access to the Internet. Supplementary material: Details of all the Smith Woodward type specimens, including images, are available at http://www.geolsoc.org.uk/SUP18874
Article
A rich lamniform selachian fauna, comprising twelve species, is recorded from the informal B. mammillatus zone of the Kristianstad Basin. Five new taxa, including a North American one, are introduced. Parasymphyseal teeth of Cretolamna are described for the first time, indicating a close kinship to Cretoxyrhina. A possibly temperature-controlled relatively high degree of endemism is demonstrated for several small to medium sized Campanian odontaspidids. It is concluded that the diversity of lamniform sharks may have been linked to the great abundance of belemnites in the basin during the B. mammillatus time. Davis's 1890 paper on Scandinavian Cretaceous/Palaeocene selachians is revised concerning the lamniforms, clarifying many locality data errors. -from Author
Article
Le Gargasien de la région de Gargas a livré une intéressante faune de poissons comprenant 14 espèces de sélaciens dont 2 nouvelles : Anomotodon principalis nov. sp. et Rhinobatos picteti nov. sp., et une espèce d'Holocéphale. Le genre Notidanodon nov. est proposé pour quelques espèces crétacées et tertiaires. Cette faune permet d'élargir la répartition géographique et stratigraphique de plusieurs espèces et apparaît comme la première faune de sélaciens de caractère "moderne".
Article
Bulk sampling of phosphate-rich horizons within the Late Cretaceous of the Anglo-Paris Basin yielded numerous teeth of members of the Squatiniformes. Along with isolated tooth remains, two museum specimens comprising partial articulated encoskeletal remains including the holotype of the species Squatina cranei Woodward, 1888a are described, and a new subgenus Cretascyllium is proposed for species of the genus Squatina with high degree of heterodonty and triangular anterior teeth. The species Squatina (Cretascyllium) cranei comb. nov. and Squatina (Cretascyllium) hassei comb. nov. are referred to this subgenus. The genus Parasquatina Herman, 1982 previously erected on a single tooth is valid, and two new species P. justinensis sp. nov. and P. jarvisi sp. nov. are described along with a third taxon Parasquatina sp. An enigmatic tooth referred to ?Neoselachii incertae sedis is also reported. The palaeoecology of these taxa is discussed.
Article
A small but diverse selachian fauna, represented by isolated teeth, is described from the lower part of the Gearle Siltstone in the Giralia Anticline, Southern Carnarvon Basin, Western Australia. It consists of: Notorynchus aptiensis, Paraorthacodus sp., Orectolobiformes gen. et sp. nov., Archaeolamna sp., Leptostyrax sp., Cretoxyrhinidae gen. et sp. incertae sedis, Cretolamna sp., Paraisurus aff. compressus, Carcharias striatula, and Squalicorax primaevus. Comparisons with known ranges of these taxa in the Northern Hemisphere place the fauna in the middle to late Albian. Contrary to previous claims, the cowshark Notorynchus aptiensis does not appear to have been primarily a Tethyan faunal element, as its teeth are more common in the cool water facies of the Gearle Siltstone than anywhere else in the world. The few previous records of Cretaceous sharks from Western Australia are revised, resulting in several systematic alterations.
Article
Screening in the Albian of Wissant area has allowed to collect an interesting selachian fauna including some new elements: Orectoloboides nov. gen., Scyliorhinus destombesi nov. sp. and Protosqualus sigei nov. gen., nov. sp.. The relationships of these forms are discussed.