Eocaecilia
| Eocaecilia | ||||||||||||
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Eocaecilia |
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| Temporal occurrence | ||||||||||||
| Lower Jurassic | ||||||||||||
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| Scientific name | ||||||||||||
| Eocaecilia | ||||||||||||
| Jenkins & Walsh , 1993 | ||||||||||||
Eocaecilia is an extinct genus of crawling amphibians whose fossils were found in the Kayenta Formation near Gold Spring in northeastern Arizona . In contrast to all of today's sneak amphibians, Eocaecilia still had four short limbs . A total of 38 specimens were found. None was complete, pelvic bones are always missing, but parts of the shoulder girdle , humerus , radius , ulna , as well as thighbones , tibia and fibula are preserved. The only species is Eocaecilia micropodia .
features
Eocaecilia's feet had three toes. The shoulder girdle is similar to that of the tailed amphibian and the extinct microsauria . The mouth was slightly below. In the upper jaw sat two rows of small, two-pointed teeth, more than in today's sneak amphibians. In contrast to recent sneak amphibians, Eocaecilia had a gill cover (operculum).
Modern features that Eocaecilia shares with recent sneak amphibians are the tentacle pit at the front edge of the eye socket , the fused skull bones and the lower jaw process, to which the second pair of muscles of the typical double jaw-closing mechanism of the sneak amphibian connects.
meaning
In addition to two fossil eddies from the Upper Cretaceous of Bolivia and the Palaeocene of Brazil, the fossils of Eocaecilia are the only fossil finds of the amphibian order. The finds are older than the oldest of the tail amphibians and show that the sneak amphibian descended from four-legged ancestors.
literature
- Werner Himstedt: The blind diggers. Westarp Science, Magdeburg 1996, ISBN 3-89432-434-1 .
- Farish A. Jenkins, Denis M. Walsh: An Early Jurassic caecilian with limbs. In: Nature . 365, 1993, pp. 246-250, doi : 10.1038 / 365246a0 .
- Farish A. Jenkins et al .: Anatomy of Eocaecilia micropodia , A Limbed Caecilian of the Early Jurassic. In: Bulletin of the Museum of Comparative Zoology. 158, No. 6, 2007, pp. 285-365, doi : 10.3099 / 0027-4100 (2007) 158 [285: AOEMAL] 2.0.CO; 2 .
further reading
- Hillary C. Maddin, Farish A. Jenkins Jr, Jason S. Anderson: The Braincase of Eocaecilia micropodia (Lissamphibia, Gymnophiona) and the Origin of Caecilians. PLoS ONE 7 (12): e50743. DOI: 10.1371 / journal.pone.0050743
Web links
- Eocaecilia at Palæos