- Tytuł:
- Autothecal morphs and dormancy in the camaroid graptolite Xenotheka
- Autorzy:
- Mierzejewski, P
- Powiązania:
- https://bibliotekanauki.pl/articles/23262.pdf
- Data publikacji:
- 2003
- Wydawca:
- Polska Akademia Nauk. Instytut Paleobiologii PAN
- Tematy:
-
Xenotheka klinostoma
Graptolithina
Camaroidea
Sweden
Ordovician
microfossil
ultrastructure
paleontology
dormancy
camaroid graptolite - Opis:
- The camaroid graptolite Xenotheka klinostoma Eisenack, 1937 is described from the lower Llanvirn limestones of Gilbergabrottet, northern Öland, Sweden. Two distinct autothecal morphs are recognized: (1) normal morph (described for the first time), i.e. an autotheca with an unsculptured outer surface, devoid of both an outer lining and autothecal occlusion, and inhabited by an active zooid; and (2) sealed morph, i.e. an autotheca coated and occluded, provided with a sculptured outer lining made of a unique verrucose fabric, and inhabited by an inactive or dormant zooid. In addition, the existence of a hypothetical (3) unsealed morph or re−opened autotheca, devoid of an autothecal occlusion but provided with an outer lining, and inhabited by a reactivated zooid, is predicted. The sealed morphs may represent an adaptation which allowed their inhabitants to survive adverse conditions. The outer lining of Xenotheka is compared with a peculiar outer membrane found in the modern hemichordate Rhabdopleura, from the intertidal zone of Fiji, and with camaroid extracamaral tissue.
- Źródło:
-
Acta Palaeontologica Polonica; 2003, 48, 1
0567-7920 - Pojawia się w:
- Acta Palaeontologica Polonica
- Dostawca treści:
- Biblioteka Nauki
Artykuł