2010年2月14日 星期日

呼吸系統的解剖構造暗示大頭龜是澤龜科(Emydidae)的姐妹群

[根據肺葉形態所重建的現生龜鼈類親緣關係, superlink: ScienceDirecet]
[肺葉形態在羊膜類動物的演化趨勢與特徵狀態, superlink: ScienceDirect]

文獻來源: Lambertz M, Bohme W, Perry SF. 2010. The anatomy of the respiratory system in Platysternon megacephalum Gray, 1831 (Testudines: Cryptodira) and related species, and its phylogenetic implications, Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology, In Press

Abstract

We discuss the morphology of the respiratory system regarding the phylogenetic relation among selected Testudines (Tetrapoda: Amniota). Lung structure and the associated coelomic organization are compared in Platysternon megacephalum and in representatives of the most-likely closely related taxa Chelydridae and Testudinoidea (Emydidae + Testudinidae). P. megacephalum shows horizontal intrapulmonary septation in the medial chambers, dividing them into dorsal and ventral lobes. This structure is found only in Platysternon and in the Emydidae, and is interpreted as a possible synapomorphy for these two taxa. In addition to further suggested synapomorphies for Platysternon and the Testudinoidea, we found - in contrast to previous reports - a small post-pulmonary septum (PPS) and incomplete coelomic compartmentalization in the Chelydridae. Thus, all major taxa of Testudines possess a PPS. Since this structure is also present in mammals, archosaurs and some lepidosaurs, the plesiomorphy of a coelomic compartmentalization by the PPS in amniotes in general should be considered. These preliminary results indicate that further comparative study of the respiratory apparatus might help resolve the phylogenetic relationships among the Testudines, as well as to shed light on its evolution among the Amniota.