Gemmell R T, Johnston G, Bryden M M
Department of Anatomy, University of Queensland, St. Lucia, Brisbane, Australia.
J Anat. 1988 Aug;159:155-64.
Skeletal development of two marsupial species, the bandicoot, Isoodon macrourus and the brushtail possum, Trichosurus vulpecula, has been examined in whole mount preparations using a technique of clearing and differential staining of cartilage and bone. Both marsupials possess a complete cartilaginous skeleton at birth and ossification begins in the maxilla, mandible and certain bones of the forelimb soon after birth. The general pattern of ossification in these marsupials is similar to that in eutherians but the long bones of the forelimbs, and the thoracic vertebrae, have a precocious development when compared with that of eutherian mammals. This difference may be due to the requirement of the marsupial forearms for the passage of the young from the cloaca to the pouch. Accelerated rib development occurs, and is possibly related to respiratory movements which are initiated at a very much earlier stage than in eutherian mammals.
利用软骨和骨骼的透明及鉴别染色技术，在整装标本中研究了两种有袋类动物的骨骼发育，这两种动物分别是袋狸（Isoodon macrourus）和帚尾袋貂（Trichosurus vulpecula）。两种有袋类动物在出生时都拥有完整的软骨骨骼，出生后不久，上颌骨、下颌骨和前肢的某些骨骼就开始骨化。这些有袋类动物的骨化总体模式与真兽类相似，但与真兽类哺乳动物相比，前肢的长骨和胸椎发育早熟。这种差异可能是由于有袋类动物的前臂需要让幼崽从泄殖腔进入育儿袋。肋骨发育加速，这可能与呼吸运动有关，呼吸运动比真兽类哺乳动物更早开始。
