Whatcheeria
Whatcheeria is an extinct genus of early tetrapod from the early Mississippian of Iowa. Fossils have been found in an old limestone quarry in the town of Delta. They date to 340 million year ago (mya). The type species W. deltae was named in 1995. It is classified with the closely related Pederpes in the family Whatcheeriidae.[1]
| Whatcheeria Temporal range: lower Mississippian, 340 mya
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| Family: | †Whatcheeriidae
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| Genus: | †Whatcheeria Lombard and Bolt, 1995
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Description
changeWhatcheeria possesses a mixture of basal and derived (advanced) traits. Like other stem tetrapods it has a series of lateral lines across the skull, and rows of teeth on the palate These are basal traits derived from its lobe-finned fish ancestors.
It has a cleithrum, a bone in the pectoral girdle that extends from the scapula. The cleithrum once attached to the skull in lobe-finned fish, the ancestors of tetrapods, but detached to allow the neck to move freely.[1]
Whatcheeria grew to about 1 metre (3.3 ft) long. The skull is deep (this is an advanced trait) and the snout is pointed. A hole on the top of the skull behind the eyes called the parietal foramen is relatively large in Whatcheeria. The bones on the skull surface are unusually smooth, unlike the pitted skulls of many other early tetrapods.[1]
Classification
changeWith modern cladistic taxonomy, Whatcheeriidae is not placed in Amphibia or any other class but simply as its own family within Tetrapoda. Its relationships with other tetrapods are left unclear.
References
change- ↑ 1.0 1.1 1.2 Lombard, R.E.; Bolt, J.R. (1995). "A new primitive tetrapod, Whatcheeria deltae, from the Lower Carboniferous of Iowa" (PDF). Palaeontology. 38 (3): 471–495. Archived from the original (PDF) on 2012-03-24. Retrieved 2012-05-25.