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1
Content available remote Systematics and dental system reconstruction of the durophagous chondrichthyan Lagarodus JAEKEL, 1898
Lebedev O.
Acta Geologica Polonica
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2008
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Vol. 58, no. 2
199-204
EN
The type species of the Carboniferous chondrichthyan genus Lagarodus JAEKEL, 1898 is changed to Psammodus specularis TRAUTSCHOLD, 1874 because of an identification error in TRAUTSCHOLD (1874). Five morphotypes: angustus, specularis, cubicus, accessory, and orobranchial are recognised. Tooth morphology, configuration of wear surfaces, growth traces on the basal surface and comparison with extant analogues were used to reconstruct the dentition.
2
Content available remote New genus of chondrichthyans from the Silurian - Devonian boundary deposits of Tuva (Russia)
Zigaite Z.
Acta Geologica Polonica
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2008
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Vol. 58, no. 2
127-131
EN
A new genus of Chondrichthyes from the uppermost Silurian.lowermost Devonian deposits of central Tuva (Russia) is described on the basis of the microremains (scales). A sample from the Khondergei Formation of the Bazhyn-Alaak locality in the Tchadan region contained scales of a new chondrichthyan, Tuvalepis schultzei gen. et sp. nov., together with another chondrichthyan, Elegestolepis grossi KARATAJUTE-TALIMAA, 1973, as well as numerous scales of the thelodont Helenolepis navicularis KARATAJUTE-TALIMAA, 1978. The scales of T. schultzei display significant morphological variation and are characterized by a very fine, comparatively wide and flat crown with longitudinal ribs and a small and short neck. The growth pattern of T. schultzei scales is very different from that of elegestolepids described so far - the scales grew by appositional addition of layers towards the distal side of the crown, in contrast to the scales of Elegestolepis grossi which lack any kind of concentric growth lines.
3
Content available remote New data on chondrichthyan microremains from the Givetian of the Renanue section in the Aragonian Pyrenees (Spain)
Ginter M., Liao J., Valenzuela-Rios J.
Acta Geologica Polonica
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2008
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Vol. 58, no. 2
165-172
EN
The continued investigations on the Middle Devonian part (Givetian, Middle through Upper Polygnathus varcus conodont Zones) of the section near the Renanue village in the Aragonian Pyrenees, Spain, brought twelve teeth of chondrichthyan taxa typical of the so-called "Omalodus shark assemblage" (Omalodus grabaui, Phoebodus fastigatus, Ph. sophiae, and probably Antarctilamna sp., the first record of Antarctilamna from the Givetian of Europe) previously known from a few places in Laurussia and North Gondwana. This taxonomic composition resembles the most that of the North Evans Limestone from New York. The species represent three different families and orders: Omalodontidae nov. (Omalodontiformes), Phoebodontidae (Phoebodontiformes), and Antarctilamnidae nov. (Antarctilamniformes nov.). In addition to the teeth of the listed taxa, several chondrichthyan scales of the "ctenacanth" type were found.
4
Content available remote Late Devonian - Early Permian chondrichthyans of the Russian Arctic
Ivanov A.
Acta Geologica Polonica
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1999
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Vol. 49, no. 3
267-285
EN
New chondrichthyan material is reported from the Upper Devonian - Lower Permian of the various regions of the Russian Arctic. Shark remains are recorded from the Novaya Zemlya Archipelago for the first time. Ten species are described, two of which are new, Denaea? decora sp.n. and Adamantina foliacea sp.n. Upper Devonian - Lower Permian shark assemblages are discussed.
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