- 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
Artykuł