Temat: chondrichthyes - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Late Oligocene sharks and rays from the Chandler Bridge Formation, Dorchester County, South Carolina, USA
Autorzy:: Cicimurri, D.J.
Knight, J.L.
Powiązania:: https://bibliotekanauki.pl/articles/21710.pdf
Data publikacji:: 2009
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:: Late Oligocene
Oligocene
shark
ray
Chandler Bridge Formation
Dorchester County
South Carolina
USA
Chondrichthyes
Neoselachii
Opis:: A diverse vertebrate fauna, dominated by elasmobranch taxa, was collected from the upper Oligocene (Chattian) Chandler Bridge Formation in Summerville, Dorchester County, South Carolina. Nearly 3,500 teeth and dermal denticles are assigned to 29 species of sharks and rays, and our sample includes the oldest known occurrence of the whale shark, Rhincodon, as well as a new skate, Raja mccollumi sp. nov. The Chandler Bridge elasmobranch assemblage is comparable in species diversity to Chattian assemblages of Virginia and North Carolina, USA, and Germany. Notable absences from Germany include Rhincodon, Hemipristis, and Sphyrna zygaena, likely reflecting the influence of colder water on the North Sea Basin during the Chattian. Squaloids, pristiophoroids, and hexanchoids are known from Chattian deposits of the Albemarle Embayment (North Carolina), Salisbury Embayment (Virginia), and North Sea Basin, but these taxa are absent from the Chandler Bridge assemblage, perhaps because of shallow, warm water (20 to 25°C) conditions within the more southerly Charleston Embayment.
Źródło:: Acta Palaeontologica Polonica; 2009, 54, 4
0567-7920
Pojawia się w:: Acta Palaeontologica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Early Pennsylvanian xenacanth chondrichthyans from the Swisshelm Mountains, Arizona, USA
Autorzy:: Johnson, G.D.
Thayer, D.W.
Powiązania:: https://bibliotekanauki.pl/articles/21790.pdf
Data publikacji:: 2009
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:: vertebrate
fauna
xenacanth chondrichthyan
chondrichthyan
Swisshelm Mountains
Arizona
USA
Chondrichthyes
Xenacanthiformes
Bransonelliformes
Orthacanthus
Triodus
Bransonella
Opis:: Three genera of xenacanths, based on isolated teeth, occur in the lepospondyl (amphibian)−dominated fauna from the upper Black Prince Limestone (late Bashkirian). Orthacanthus donnelljohnsi sp. nov. teeth, with carinae lacking serrations on the compressed principal cusps, and only one intermediate cusp, represent both adult and juvenile teeth. Heterodonty occurs in both adult and juvenile dentitions. The absence of serrations is unique among Pennsylvanian species of Orthacanthus. Teeth with often highly asymmetrical bases with an aborally−flexed lingual marginal flange (= anterolingual shelf) and a single intermediate cusp are assigned to Triodus elpia sp. nov. A central foramen occurs in the base, unlike most other species; the moderately compressed principal cusps bear generally straight cristae. They represent the first reported occurrence of Triodus in the Paleozoic of North America. Five teeth, with cristae extending from the cusps onto their bases, belong to Bransonella. Two are questionably assigned to Bransonella nebraskensis, one to B. ?lingulata with its labio−lingually elongated apical button and smaller than normal intermediate cusp, and one each to Bransonella sp. “A” and “B”. Bransonella sp. “A” has a base wider (labio−lingual) than long, the reverse of the other Bransonella teeth. Bransonella sp. “B” is distinctly different, as it lacks an intermediate cusp (as in some B. lingulata teeth), and the basal tubercle is beneath one of the cusps (with no evidence of deformity).
Źródło:: Acta Palaeontologica Polonica; 2009, 54, 4
0567-7920
Pojawia się w:: Acta Palaeontologica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Morphology and histology of dorsal spines of the xenacanthid shark Orthacanthus platypternus from the Lower Permian of Texas, USA: palaeobiological and palaeoenvironmental implications
Autorzy:: Beck, K.G.
Soler-Gijon, R.
Carlucci, J.R.
Willis, R.E.
Powiązania:: https://bibliotekanauki.pl/articles/21629.pdf
Data publikacji:: 2016
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:: morphology
histology
dorsal spine
xenacanthid shark
shark
Orthacanthus platypterus
Chondrichthyes
Xenacanthiformes
Lower Permian
Texas
USA
paleobiology
paleoenvironment
Opis:: Detailed studies on Carboniferous species of the xenacanth Orthacanthus have shown that the xenacanth dorsal fin spine can be used for skeletochronological analyses and provides valuable information about development, growth and environmental life conditions of those extinct sharks. We report here for the first time the histology and skeletochronology of Permian specimens, dorsal spines of Orthacanthus platypternus from the Craddock Bone Bed (lower Clear Fork Formation; Early Permian, Leonardian age) of northern Baylor County (north-central Texas, USA). Twelve dorsal spines of O. platypternus preserve a highly vascularized wall mainly composed of centrifugally growing dentine in a succession of dentine layers, probably deposited with an annual periodicity. As expected, spines of individuals with 1–2 dentine layers, presumably juveniles, present the smallest sizes. However, spines of individuals showing at least 3–4 dentine layers and interpreted to be subadults/young adults, are distributed in two spine-size clusters corresponding to females (probably the largest spines) and males, in agreement with the hypothesis of sexual size dimorphism proposed in a previous biometric analysis. Our comparative study of O. platypternus and the Stephanian species O. meridionalis further suggests that spine denticulation can be useful for distinguishing between species of Orthacanthus and sexually dimorphic forms (juvenile to adults) in each species. Total body length estimations of O. platypternus from the Craddock Bone Bed point to relatively large juveniles and small subadults/young adults (less than 2 m in total length), living as opportunistic predators in the pond-channel coastal plain environments represented by the bone bed deposits. The comparative analyses of the ontogenetic stages of the recorded specimens of O. platypternus and their distribution along different facies and localities indicate that this species was euryhaline, diadromous with a catadromous life-cycle which was strongly regulated by the semi-arid, seasonally dry tropical climate affecting western Pangaea during the Early Permian.
Źródło:: Acta Palaeontologica Polonica; 2016, 61, 1
0567-7920
Pojawia się w:: Acta Palaeontologica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: A preliminary note of egg-case oviparity in a Devonian placoderm fish
Autorzy:: Carr, R. K.
Jackson, G.
Powiązania:: https://bibliotekanauki.pl/articles/139073.pdf
Data publikacji:: 2018
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: Devonian
Famennian
Cleveland Shale
Ohio
USA
Placodermi
Arthrodira
oviparity
egg case
Chondrichthyes
dewon
famen
ryby pancerne
tarczowce
plakodermy
zawiasowce
jajorodność
ryby chrzęstnoszkieletowe
ryby chrzęstne
chrzęstniki
Opis:: Six enigmatic fossils from the Famennian (Devonian) Cleveland Shale in Ohio, U.S.A., are interpreted here as arthrodiran (Placodermi) egg cases. Recognition as egg cases is confirmed based on the observation of layered collagen fibers. The presence of a tuberculated bone fragment preserved within one case confirms a vertebrate source. The nature of the tubercles and the unique morphology of the egg cases supports the interpretation of an arthrodiran source. Reports of Devonian egg cases are limited to either assumed chondrichthyan producers or a putative ‘egg sac’ with a morphology atypical for any vertebrate. The Cleveland Shale egg cases thus represent the first record for a non-chondrichthyan producer. Among placoderms, behaviors of a pelagic life style with obligate nesting sites, reef fishes with live birth, and estuarine and fluvial nurseries, along with eggcase oviparity testifies to the diversity of reproductive strategies. As with modern fishes these strategies may be ecologically driven and the derived and variable reproductive biology of extant chondrichthyans is actually a primitive condition among gnathostomes. One consequence of the diversity of reproductive strategies (dependent on the topology of relationships) is the independent origin of internal fertilization within placoderms, possibly suggesting external fertilization as the primitive gnathostome reproductive mode.
Źródło:: Acta Geologica Polonica; 2018, 68, 3; 381-389
0001-5709
Pojawia się w:: Acta Geologica Polonica
Dostawca treści:: Biblioteka Nauki