Large deadfalls of the ʻginsuʼ shark Cretoxyrhina mantelli (Agassiz, 1835) (Neoselachii, Lamniformes) from the Upper Cretaceous of northeastern Italy (original) (raw)
Related papers
Reassessment of a large lamniform shark from the Upper Cretaceous (Santonian) of Italy
Cretaceous Research, 2019
To date, only a few partially articulated cartilaginous specimens are known from the Upper Cretaceous marine fossil record of northern Italy. Here, we re-evaluate the taxonomic status and geological age of selachian remains originally discovered during the th century from the Castellavazzo locality. The described specimen is largely embedded in matrix with minute exposure of joined and moderately deformed sequentially stacked vertebral centra. CT-tomographic image-data obtained of the specimen enabled the identification of potential cranial-cartilage located in close proximity to teeth and are here interpreted as remnants of the jaws. Based on tooth and vertebral morphology the specimen is in all likelihood an adult lamniform shark with a measured3.5 m length. Using ordinary least-squares regression analysis (OLS) and proportion-based calculations, we estimated a total-length (TL) of 596.27 and 632.5-672.64 cm respectively. We consider the size estimation derived through OLS bivariate regression more accurate; however, the present analysis, rely on a small sample size (n = 11) and evidence for differential scaling between taxa, impose limitations on the precision of our size prediction. Planktonic foraminifera examined from the surrounding matrix of the slab preserving shark vertebral centra and teeth indicate a Santonian age (Dicarinella asymetrica zone). Although, the specimen could not confidently be assigned beyond the ordinal-level; the sheer centrum size, gross dental morphology, and depositional environment, is indicative of a pelagic apex-predator comparable to coeval lamniforms, with a specific resemblance towards cretoxyrhinids, reported from elsewhere along the peri-Tethyan shelf of Europe and Western Interior Seaway of North America. Finally, the re-emergence of this historical specimen, here re-described using cutting-edge techniques, is of great importance as it contributes to the otherwise poor record of extinct lamniform shark skeletons.
Journal of Paleontology, 2022
The definition of the Cretaceous shark genus Cretodus Sokolov, 1965 is primarily based on isolated teeth. This genus includes five species. Among these, Cretodus houghtonorum Shimada and Everhart, 2019 is the only species based on a partially preserved skeleton. Here, the taxonomic attribution of a virtually complete skeleton of Cretodus from the Turonian of northeastern Italy is discussed, together with a few specimens from the Turonian of England. One of the latter is investigated through micropaleontological analysis to determine its stratigraphic position. The material is referred to Cretodus crassidens (Dixon, 1850), the diagnosis of which is emended herein. The dentition is tentatively reconstructed, exhibiting strong similarities with congeneric species, although it differs in having strong vertical folds on the main cusp labial face, a mesiodistally broad tooth aspect, weak and well-spaced 'costulae' at crown base, and a different dental formula in the number of parasymphyseal and lateral rows. Some tooth malformations are interpreted as feeding-related or senile characters. The Italian specimen suggests that Cretodus crassidens had a wide and laterally expanded mouth and head, a stout body, and attained a gigantic size. Cretodus crassidens was a moderate-speed swimming shark ecologically like the extant tiger shark Galeocerdo cuvier (Péron and Lesueur in Lesueur, 1822). The age estimate from vertebral-band counting suggests that the Italian individual was at least 23 years old and the growth model indicates a longevity of 64 years and a maximum attainable total length of 9-11 m. Cretodus crassidens occurs both in Boreal and Tethyan domains, implying a broad paleobiogeographic distribution and a preference toward offshore settings. Geological setting The geological setting of the 'Lastame' lithofacies of the Scaglia Rossa of the Lessini Mountains (∼30 km N of Verona, Veneto, Italy; Fig. 1), which yielded the Cretodus remains, has been thoroughly described in a series of papers dealing with the remarkable vertebrate assemblage of this Cretaceous Lagerstätte *Corresponding author.
Journal of Vertebrate Paleontology
We describe a partial skeleton of the Late Cretaceous shark, Cretodus, collected from the Blue Hill Shale (middle Turonian) in north-central Kansas, U.S.A. It consists of 134 disarticulated teeth, 61 vertebrae, 23 placoid scales, and fragments of calcified cartilage. The scale morphology suggests that Cretodus was a rather sluggish shark, and the vertebral morphology affirms its placement into Lamniformes. With a strong tendency towards monognathic heterodonty, the dental morphology indicates that the specimen belongs to a new species, C. houghtonorum, sp. nov., increasing the total known species of Cretodus to five. The five species can be divided into three distinct groups: the longiplicatus/semiplicatus-grade, gigantea/houghtonorumgrade, and crassidens-grade. Cretodus, that successively evolved by broadening the tooth crown. The individual of C. houghtonorum, sp. nov., is estimated to be about 515 cm in total length (TL). Our vertebra-based growth analysis suggests that the shark was about 118 cm TL at birth and that the species had an estimated maximum growth length of 684 cm TL. The large size at birth indicates that the intrauterine cannibalism behavior of embryos seen in extant lamniforms had already evolved by the Late Cretaceous. Where C. houghtonorum, sp. nov., preferred nearshore environments, the specimen cooccurred with isolated teeth of Squalicorax and fragments of two dorsal fin spines of a hybodont shark, circumstantially indicating that the individual of Cretodus fed on the much smaller hybodont and was scavenged by Squalicorax.
A new early cretaceous lamniform shark (Chondrichthyes, Neoselachii)
Zoological Journal of The Linnean Society, 2008
Eoptolamna eccentrolopha gen. et sp. nov. (Chondrichthyes, Lamniformes) from the near coastal upper Barremian Artoles Formation (Early Cretaceous) of Castellote (northwestern Spain) is described on the basis of about 50 isolated teeth. This taxon represents one of the earliest lamniform sharks known to date. We hypothesize that most pre-Aptian lamniforms belong to an ancient group characterized, amongst others, by a very weak gradient monognathic heterodont dental pattern, and by tearing-type dentition. There is a nutritive groove in the lingual root protuberance in juveniles of Eoptolamna, which persists in adults. A single pair of symphysial and a pair of upper intermediate teeth might have been present. Consequently, a new family, Eoptolamnidae, is introduced to include the new form, as well as Protolamna and probably Leptostyrax. The Eoptolamnidae represent an ancient family within Lamniformes. The origin of lamniform sharks remains, however, ambiguous despite recent advances. The new Spanish taxon is widespread in the Barremian of north-eastern Spain, and occurs in a wide range of facies from near-coastal to lake deposits. This lamniform also occurs in the Lower Cretaceous of northern Africa. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154, 278–290.
1998
Abstract-O. vu. moseladu: stcnosonw gen. et sp. nov. is a small shark described on the basis of 47 specimens in various sta tes of aniculation and association from the spongolithic micritcs of the Lombardische Kieselkalk formation (Arietites b'"'k landi zone. Sincmurian, Early Jurassic) of Osteno (Lake Cercsio. Lombardy. northern Italy). Osrenoselache is placed in the Family Ostenoscluchidac fam. nov. of uncertain posttion within the neoselacbjan sharks (inct? rtae:; uperurdinae). ll1e ana tomy is described in detail.
A new bathyal shark fauna from the Pleistocene sediments of Fiumefredo (Sicily, Italy)
Geodiversitas, 2007
A new shark fauna is described from the lower-middle Pleistocene marine sediments outcropping near the Fiumefreddo village, Southern Italy. Th e fossil assemblage mostly consists of teeth belonging to the bathydemersal and bathypelagic elasmobranch species Chlamydoselachus anguineus, Apristurus sp., Galeus cf. melastomus, Etmopterus sp., Centroscymnus cf. crepidater, Scymnodon cf. ringens, Centrophorus cf. granulosus and C. cf. squamosus, commonly recorded along the extant outer continental shelf and upper slope. From a bathymetrical point of view, the present vertical distribution of the taxa collected allows an estimate of a depth between 500 and 1000 m. Th e bathyal character of the fauna provides new evidence of a highly diversifi ed and heterogeneous deep-sea Mediterranean Plio-Pleistocene marine fauna, in response to the climatic and hydrographical changes. Finally, the Fiumefreddo fauna provides new relevant data for the understanding of the processes involved in the evolution of the extant Mediterranean selachian fauna. RÉSUMÉ Une nouvelle faune de requins bathyaux des sédiments du Pléistocène de Fiumefreddo (Sicile, Italie). Une nouvelle faune de sélaciens bathyaux est décrite des sédiments marins du Pléistocène inférieur-moyen de Fiumefreddo, Italie méridionale. L'association fossile comprend en majorité des dents attribuées à des espèces d'élasmobranches bathydémersaux et bathypélagiques Chlamydoselachus anguineus, Apristurus sp.,
Zoological Journal of the Linnean Society
Eoptolamna eccentrolopha gen. et sp. nov. (Chondrichthyes, Lamniformes) from the near coastal upper Barremian Artoles Formation (Early Cretaceous) of Castellote (northwestern Spain) is described on the basis of about 50 isolated teeth. This taxon represents one of the earliest lamniform sharks known to date. We hypothesize that most pre-Aptian lamniforms belong to an ancient group characterized, amongst others, by a very weak gradient monognathic heterodont dental pattern, and by tearing-type dentition. There is a nutritive groove in the lingual root protuberance in juveniles of Eoptolamna, which persists in adults. A single pair of symphysial and a pair of upper intermediate teeth might have been present. Consequently, a new family, Eoptolamnidae, is introduced to include the new form, as well as Protolamna and probably Leptostyrax. The Eoptolamnidae represent an ancient family within Lamniformes. The origin of lamniform sharks remains, however, ambiguous despite recent advances. The new Spanish taxon is widespread in the Barremian of northeastern Spain, and occurs in a wide range of facies from near-coastal to lake deposits. This lamniform also occurs in the Lower Cretaceous of northern Africa.
Palaeontology, 2008
Bulk sampling of phosphate-rich horizons within the British Coniacian to Campanian (Upper Cretaceous) yielded very large samples of shark and ray teeth. All of these samples yielded teeth of diverse members of the Carcharhiniformes, which commonly dominate the fauna. The following species are recorded and described: Pseudoscyliorhinus reussi (Herman, 1977) comb. nov., Crassescyliorhinus germanicus (Herman, 1982) gen. nov., Scyliorhinus elongatus (Davis, 1887), Scyliorhinus brumarivulensis sp. nov., ?Palaeoscyllium sp., Prohaploblepharus riegrafi (Müller, 1989) gen. nov., ?Cretascyliorhinus sp., Scyliorhinidae incertae sedis 1, Scyliorhinidae incertae sedis 2, Pteroscyllium hermani sp. nov., Protoscyliorhinus sp., Leptocharias cretaceus sp. nov., Palaeogaleus havreensis Herman, 1977, Paratriakis subserratus sp. nov., Paratriakis tenuis sp. nov., Paratriakis sp. indet. and ?Loxodon sp. Taxa belonging to the families ?Proscylliidae, Leptochariidae and Carcharhinidae are described from the Cretaceous for the first time. The evolutionary and palaeoecological implications of these newly recognised faunas are discussed.