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A preliminary note of egg-case oviparity in a Devonian placoderm fish

Carr R. K., Jackson G.

Acta Geologica Polonica

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2018

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Vol. 68, no. 3

381--389

EN

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.

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A new aspinothoracid arthrodire from the Late Devonian of Ohio, U.S.A.

Carr R. K.

Acta Geologica Polonica

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2018

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Vol. 68, no. 3

363--379

EN

The Cleveland Shale fauna represents a unique view of the time after a major Devonian extinction event (Frasnian–Famenian) with the recovery of arthrodires (Placodermi) best represented by this most specious North American fauna. This time was followed by an additional event (Hangenberg Biocrisis) leading to the extinction of arthrodires (and all other placoderms). An understanding of the diversity and interrelationships of North American arthrodires can aid our understanding of this critical time in vertebrate evolution. A new aspinothoracid arthrodire Hlavinichthys jacksoni gen. et sp. nov. is described from the Late Devonian of northern Ohio, U.S.A., which adds to our knowledge of this group. It provides a point of comparison to other members of the fauna whose interrelationships are poorly known. A phylogenetic analysis supports an assignment of Hlavinichthys jacksoni gen. et sp. nov. among the aspinothoracid arthrodires. This work has drawn attention to the continued need for descriptive and phylogenetic analyses of this unique fauna. Decades old species descriptions need revision along with preparation and description of new taxa. The work on Hlavinichthys jacksoni gen. et sp. nov. here is one step in that process.

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Zróżnicowanie facjalne a skamieniałości późnodewońskich plakodermów w Górach Świętokrzyskich

Szrek P.

Przegląd Geologiczny

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2006

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Vol. 54, nr 6

521-524

EN

Main Late Devonian placoderm taxa known from the Holy Cross Mountains are characterised. The distribution of the Late Devonian placoderm fossils is described. Variation in their occurrences depend on the sedimentation environment of the rocks which contain fossils of this group. Connections between the Holy Cross Mountains placoderms development and the synsedimentary tectonic processes active in this area during the Late Devonian is discussed, and the local faunas compared to classic assemblages of the same age from Latvia.

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Skamieniałości Antiarcha (Vertebrata, Placodermi) w dewonie Gór Świętokrzyskich

Szrek P.

Przegląd Geologiczny

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2006

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Vol. 54, nr 7

610-614

EN

The paper indicates a similarity between remains of various Palaeozoic fishes thus hindering identification of fossil of Antiarcha—rare placoderms in the Holy Cross Mountains. A comparison of the vertebrate fossil assemblage from Lode Famennian delta deposits in Latvia with that from the Lower Devonian “Placoderm Sandstone” of the Podłazie hill in the Holy Cross Mountains (Poland) shows their similarity. It indicates a fluvial (?deltaic) origin of the “Placoderm Sandstone” from Podłazie. Additionally, fragmentary antiarch plates are revealed from the Frasnian of the Wietrznia Quarry in Kielce (Holy Cross Mountains).

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The first articulated antiarch (Vertebrata, Placodermi) from the Upper Devonian of the Holy Cross Mountains (central Poland)

Szrek P.

Acta Geologica Polonica

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2004

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Vol. 54, no. 3

401--406

EN

The first articualted antiarch, Bothriolepis jazwicensis sp. nov., from the lowermost Fammenian (Upper Devonian) of the Jaźwica Quarry (Łgawa Hill) near Kielce, in the Holy Cross Mountains (central Poland), is described. B. jazwicensis sp. nov. Is distinguished from all other species of Bothriolepis especially by possessing long and narrow armour and many unusual proportions of the head-shield and trunk-shield plates. This is the most complete specimen of a placoderm ever found in the Holy Cross Mountains and its state of preservation precludes its longer post mortem transport.

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Nowe dane na temat fauny kręgowców w "piaskowcach plakodermowych" z rejonu Daleszyc (Góry Świętokrzyskie)

Szrek P.

Przegląd Geologiczny

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2003

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Vol. 51, nr 5

409-411

PL

Na podstawie wstępnej analizy oznaczeń fauny z "piaskowców plakodermowych" Güricha (1896) oraz Czarnockiego (1919) i porównaniem ich z nową kolekcją (nr OS-223) stwierdzono, że oznaczenie tejże fauny na poziomie rodzajów i gatunków, jest bardzo niepewne i może budzić kontrowersje. Nie mogąc jednak przebadać kolekcji Güricha i Czarnockiego (zaginęły w czasie wojny), autor po analizie swojego materiału potwierdził obecność prawie wszystkich wymienionych przez Güricha (1896) i Czarnockiego (1919) rzędów i rodzin ryb pancernych. Stwierdzono występowanie licznych przedstawicieli Arthrodira, a także odcisków płyt przedstawicieli rzędu Antiarcha, którego obecność w dewonie świętokrzyskim w ogóle, była wątpliwa.

EN

Preliminary analysis of descriptions of "Placoderm Sandstone "fauna by Giirich (1896) and Czarnocki (1919), and comparison with the author 's new collection (no. OS-223), revealed that identification of that fauna at the species level is dubious. It is unlikely to see the Giirich and Czarnocki 's collections (lost during the war time). Review of the newly collected material confirmed the presence of almost all the orders and families of placoderm fish listed by Giirich and Czarnocki. Especially important is the rediscovery of fragments ofantiarchs, as the whose presence of the order Antiarcha in the Devonian of the Holy Cross Mountains was doubted. Besides, the presence of the Arthrodira representatives is documented.