Vater Milos
Institute of Zoology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
J Anat. 2007 Sep;211(3):290-5. doi: 10.1111/j.1469-7580.2007.00768.x. Epub 2007 Jul 20.
According to current knowledge, only the prefrontal bone (os prefrontale) of the circumorbital series is preserved in the family Salamandridae. However, the exact origin and number of ossification centres creating this bone is unknown. Detailed examination of the prefrontal bone during ontogeny of juvenile and adult specimens of the Alpine Newt (Triturus alpestris) indicates its dual origin (prefrontal and lacrimal). We found that the prefrontal bone originates from four ossification centres, i.e. three prefrontal centres and one posterior lacrimal centre. The anterior lacrimal centre participates in the maxillar ossification. The development of these ossification centres occurs very late in ontogeny (at stage 54), and starts after differentiation of the nasal capsules. The total fusion of the lacrimal ossification centre with the prefrontal bone of T. alpestris is distinct from the fully differentiated lacrimal bone attached to the prefrontal bone of the fossil family Branchiosauridae (Temnospondyly). We propose that heterochrony, observed in the recent species, is a delayed development followed by accelerated ossification that resulted in the fusion of the anterior lacrimal centre with the maxilla and the posterior lacrimal centre with the prefrontal bone.
根据目前的认识，有尾目蝾螈科动物仅保留了眶周骨系列中的额前骨（os prefrontale）。然而，形成这块骨头的骨化中心的确切起源和数量尚不清楚。对高山蝾螈（Triturus alpestris）幼体和成体标本个体发育过程中的额前骨进行详细检查后发现，它有双重起源（额前骨和泪骨）。我们发现额前骨起源于四个骨化中心，即三个额前中心和一个后泪中心。前泪中心参与上颌骨的骨化。这些骨化中心的发育在个体发育过程中非常晚才发生（在第54阶段），且在鼻囊分化之后开始。高山蝾螈泪骨化中心与额前骨的完全融合，与化石科枝螈科（离片锥目）额前骨上附着的完全分化的泪骨不同。我们认为，在现存物种中观察到的异时性现象，是一种发育延迟，随后是加速骨化，导致前泪中心与上颌骨融合，后泪中心与额前骨融合。
