Stable isotope study of a new chondrichthyan fauna   (Kimmeridgian, Porrentruy, Swiss Jura): an unusual   freshwater-influenced isotopic composition for the hybodont shark   &amp;lt;i&amp;gt;Asteracanthus&amp;lt;/i&amp;gt;

Leuzinger, Léa; Kocsis, László; Billon‐Bruyat, Jean‐Paul; Spezzaferri, Silvia; Vennemann, Torsten

doi:10.5194/bgd-12-12899-2015

Cited by 5 publications

(6 citation statements)

References 37 publications

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“…In previous studies δ 18 O PO4 from enameloid and dentine showed no significant differences for the given setting [ 29 , 37 ]. Moreover, bulk sampling is commonly employed when only small teeth or not enough samples are available [ 33 – 35 , 86 ]. In the case of batoids, most of the sampled material consists of dentine.…”

Section: Methodsmentioning

confidence: 99%

Neogene sharks and rays from the Brazilian ‘Blue Amazon’

et al. 2017

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The lower Miocene Pirabas Formation in the North of Brazil was deposited under influence of the proto-Amazon River and is characterized by large changes in the ecological niches from the early Miocene onwards. To evaluate these ecological changes, the elasmobranch fauna of the fully marine, carbonate-rich beds was investigated. A diverse fauna with 24 taxa of sharks and rays was identified with the dominant groups being carcharhiniforms and myliobatiforms. This faunal composition is similar to other early Miocene assemblages from the proto-Carribbean bioprovince. However, the Pirabas Formation has unique features compared to the other localities; being the only Neogene fossil fish assemblage described from the Atlantic coast of Tropical Americas. Phosphate oxygen isotope composition of elasmobranch teeth served as proxies for paleotemperatures and paleoecology. The data are compatible with a predominantly tropical marine setting with recognized inshore and offshore habitats with some probable depth preferences (e.g., Aetomylaeus groups). Paleohabitat of taxa particularly found in the Neogene of the Americas ( †Carcharhinus ackermannii, †Aetomylaeus cubensis) are estimated to have been principally coastal and shallow waters. Larger variation among the few analyzed modern selachians reflects a larger range for the isotopic composition of recent seawater compared to the early Miocene. This probably links to an increased influence of the Amazon River in the coastal regions during the Holocene.PLOS ONE | https://doi.org/10.1371/journal.pone

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Section: Methodsmentioning

confidence: 99%

Neogene sharks and rays from the Brazilian ‘Blue Amazon’

et al. 2017

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“…). Euryhaline character of the hybodont Asteracanthus , recently demonstrated through stable isotope analyses, so far only in the study area (Leuzinger et al . ).…”

Section: Water Salinitymentioning

confidence: 97%

“…Leuzinger et al . () demonstrated with stable isotope analyses that this genus tolerated reduced salinity, broadening the range of potential ecological niches and prey items.…”

Section: Palaeoecologymentioning

confidence: 99%

A new chondrichthyan fauna from the Late Jurassic of the Swiss Jura (Kimmeridgian) dominated by hybodonts, chimaeroids and guitarfishes

Leuzinger¹,

Cuny

Popov

et al. 2017

Papers in Palaeontology

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The fossil record of chondrichthyans (sharks, rays and chimaeroids) principally consists of isolated teeth, spines and dermal denticles, their cartilaginous skeleton being rarely preserved. Several Late Jurassic chondrichthyan assemblages have been studied in Europe based on large bulk samples, mainly in England, France, Germany and Spain. The first study of this kind in Switzerland is based on controlled excavations in Kimmeridgian deposits related to the construction of the A16 motorway in the Swiss Jura (Porrentruy, NW Switzerland). This study is based on more than 2000 isolated chondrichthyan remains (teeth, dental plates, spines and dermal denticles) and adds to our knowledge of the chondrichthyan distribution at a regional scale in Europe. We describe and identify this new fauna, define a new species of hybodont with crushing-type dentition (Asteracanthus udulfensis sp. nov.) and report for the first time the carcharhiniform Corysodon cirinensis in Switzerland. By the Late Jurassic, modern neoselachian sharks had overtaken hybodonts in European marine realms, the latter being gradually confined to brackish or freshwater environments. However, while the associated fauna of the Porrentruy platform indicates marine conditions, neoselachian sharks are surprisingly rare. The chondrichthyan assemblage is largely dominated by hybodonts, guitarfishes (rays) and chimaeroids that are all known to be euryhaline. This unexpected chondrichthyan faunal composition questions the presence of fresh to brackish water in the vicinity of the platform, and the occurrence of salinity fluctuations within a general context marine. This could explain the scarcity of neoselachian sharks and the extended success of hybodonts in the Porrentruy area as late as the Late Jurassic.

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“…During the Kimmeridgian, the climate of the Jura carbonate platform was semi-arid subtropical to Mediterranean with strong seasonal differences between prolonged, warm, dry summers and relatively short, wet winters, e.g., [39–44]. The presence of freshwater on the platform is corroborated by the occurrence of charophytes [45,46] and hybodontid shark teeth that display an unusual freshwater isotopic signal [47]. …”

Section: General Settingmentioning

confidence: 99%

Megalosauripus transjuranicus ichnosp. nov. A new Late Jurassic theropod ichnotaxon from NW Switzerland and implications for tridactyl dinosaur ichnology and ichnotaxomy

et al. 2017

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A new ichnospecies of a large theropod dinosaur, Megalosauripus transjuranicus, is described from the Reuchenette Formation (Early–Late Kimmeridgian, Late Jurassic) of NW Switzerland. It is based on very well-preserved and morphologically-distinct tracks (impressions) and several trackways, including different preservational types from different tracksites and horizons. All trackways were excavated along federal Highway A16 near Courtedoux (Canton Jura) and systematically documented in the field including orthophotos and laserscans. The best-preserved tracks were recovered and additional tracks were casted. Megalosauripus transjuranicus is characterized by tridactyl tracks with clear claw and digital pad impressions, and notably an exceptionally large and round first phalangeal pad on the fourth digit (PIV1) that is connected to digit IV and forms the round heel area. Due to this combination of features, M. transjuranicus clearly is of theropod (and not ornithopod) origin. M. transjuranicus is compared to other Megalosauripus tracks and similar ichnotaxa and other unassigned tracks from the Early Jurassic to Early Cretaceous. It is clearly different from other ichnogenera assigned to large theropods such as Eubrontes–Grallator from the Late Triassic and Early Jurassic or Megalosauripus–Megalosauropus–Bueckeburgichnus and Therangospodus tracks from the Late Jurassic and Early Cretaceous. A second tridactyl morphotype (called Morphotype II) is different from Megalosauripus transjuranicus in being subsymmetric, longer than wide (sometimes almost as wide as long), with blunt toe impressions and no evidence for discrete phalangeal pad and claw marks. Some Morphotype II tracks are found in trackways that are assigned to M. transjuranicus, to M.? transjuranicus or M. cf. transjuranicus indicating that some Morphotype II tracks are intra-trackway preservational variants of a morphological continuum of Megalosauripus transjuranicus. On the other hand, several up to 40 steps long trackways very consistently present Morphotype II features (notably blunt digits) and do not exhibit any of the features that are typical for Megalosauripus (notably phalangeal pads). Therefore, it is not very likely that these tracks are preservational variants of Megalosauripus transjuranicus or Megalosauripus isp. These trackways are interpreted to have been left by an ornithopod dinosaur. The high frequency of large theropod tracks in tidal-flat deposits of the Jura carbonate platform, associated on single ichnoassemblages with minute to medium-sized tridactyl and tiny to large sauropod tracks has important implications for the dinosaur community and for paleoenvironmental and paleogeographical reconstructions. As with most other known occurrences of Megalosauripus tracks, M. transjuranicus is found in coastal settings, which may reflect the preference of their theropod trackmakers for expanded carbonate flats where food was abundant.

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Stable isotope study of a new chondrichthyan fauna (Kimmeridgian, Porrentruy, Swiss Jura): an unusual freshwater-influenced isotopic composition for the hybodont shark <i>Asteracanthus</i>

Cited by 5 publications

References 37 publications

Neogene sharks and rays from the Brazilian ‘Blue Amazon’

Neogene sharks and rays from the Brazilian ‘Blue Amazon’

A new chondrichthyan fauna from the Late Jurassic of the Swiss Jura (Kimmeridgian) dominated by hybodonts, chimaeroids and guitarfishes

Megalosauripus transjuranicus ichnosp. nov. A new Late Jurassic theropod ichnotaxon from NW Switzerland and implications for tridactyl dinosaur ichnology and ichnotaxomy

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