A Devonian tetrapod-like fish and the evolution of the tetrapod body plan

Article Abstract:

The discovery of a well-preserved species of fossil sarcopterygian fish from the Late Devonian of Arctic Canada that represents an intermediate between fish with fins and tetrapods with limbs, and provides unique insights into how and in what order important tetrapod characters arose is presented. Though the body scales, fin rays, lower jaw and palate are comparable to those in more primitive sarcopterygians, the new species also has a shortened skull roof, a modified ear region, a mobile neck, a functional wrist joint, and other features that presage tetrapod conditions.

Canada, Natural history, Devonian period

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The pectoral fin of Tiktaalik roseae and the origin of the terapod limb

Article Abstract:

The expanded array of distal endochondral bones and synovial joints in the fin of Tiktaalik roseae is similar to the distal limb pattern of basal tetrapods. The fin of Tiktaalik is capable of a range of postures, including a limb-like substrate-supported stance in which the shoulder and elbow are flexed and the distal skeleton extended and the origin of limbs probably involved the elaboration and proliferation of features already present in the fins of fish such as Tiktaalik.

United States, History

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Haramiyids and triassic mammalian evolution

Article Abstract:

Haramiyid dentaries have been discovered in the Upper Triasic of East England. Features shared by the haramiyids with other mammals based on the find are differentiated teeth and multirooted molariforms. Haramiyids are found to be highly specialized mammals with a unique pattern of puncture-crushing occlusion that is different from the grinding or shearing mechanisms of other Early Mesozoic mammals.

Research, Paleontology, Mammals, Fossil, Fossil mammals, Triassic period

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