Ontogenetic series are rarely preserved in the fossil record, but when present they provide valuable insight into life history, developmental, and evolutionary patterns in extinct taxa. Here, we describe an intact, three-dimensionally preserved skull of Pasawioops mayi (Amphibamiformes, Micropholidae), which has not been fully described previously. Together with the holotype, also an intact skull, these two specimens of Pasawioops are interpreted as part of an ontogenetic series. The two specimens differ in traits that are thought to change during ontogeny in temnospondyls, including elongation of the postorbital region, transformation of the palatal dentition from small groups of denticles to significantly larger teeth, and a posteriorly shifting lower jaw articulation. We survey previously described amphibamiform taxa and use the ontogenetic data derived from Pasawioops to identify other potential ontogenetic series (e.g., Eoscopus). Additionally, we briefly compare amphibamiform ontogenetic series to known ontogenetic data of olsoniform and micromelerpetontid dissorophoids, and other early tetrapod lineages, to determine the extent to which ontogeny may or may not be conserved across these lineages. Several aspects of the ontogeny of Pasawioops are found to be present in lissamphibians and Amphibamiformes (i.e., branchiosaurids and amphibamids), revealing that some ontogeny-dependent traits are highly conserved within this group, whereas others are more broadly conserved across other tetrapod lineages.

化石记录很少保存在化石记录中，但是当存在时，它们为灭绝生物群的生活史，发育和进化模式提供了宝贵的见识。在这里，我们描述了完整的，保存完好的3头Pasawioops mayi头骨（两栖类，小伞形目），此前尚未对其进行完整描述。连同完整完整的头骨的完整版一起，这两个Pasawioops标本被解释为本体论系列的一部分。两种标本的特征不同，据认为在个体发育过程中会发生突触性脊柱突的改变，包括眶后区域的延长，齿从小类的细齿到明显更大的牙齿的转变，以及下颌的关节向后移动。我们调查了先前描述的两栖类生物分类群，并使用了来自Pasawioops的个体发育数据来识别其他潜在的个体发育系列（例如，Eoscopus）。此外，我们简要地比较了两亲型的个体发育系列与已知的olsoniform和micromelerpetontid dissophophoids以及其他早期四足动物谱系的个体发育数据，以确定在这些谱系中个体保守性的程度。发现两栖类和两栖类动物中存在Pasawioops个体发育的几个方面（即，分支龙和两栖动物），这表明该群体中某些个体发育相关的性状是高度保守的，而其他四足动物谱系则具有更广泛的保守性。