Upper Triassic semionotids from western Gondwana

Semionotids是最重要的，虽然了解较少的基础新翼鱼类。它们代表了这一类群的第一个也是最重要的分支之一，这一类群还包括硬骨鱼，因此也包括大多数现代硬骨鱼。因此，了解基新翼类的系统发育关系和进化对于理解硬骨鱼的进化和生物多样性至关重要。由于硬骨鱼类起源于晚三叠世，因此，像半鱼目这样的基底新龙类的早期历史特别令人感兴趣。早期的化石记录主要是偏向于北方半球的semionotiforms和很少知道的起源和第一次辐射在冈瓦纳。阿根廷的大陆上三叠统Cacheuta组（Norian）是冈瓦纳三叠纪中极少数的该组记录之一，也是南美洲唯一的三叠纪有关节的半电离层遗迹。因此，这条鱼，Semionotus vallejensis，代表了一个独特的机会，可以深入了解冈瓦纳西部semionotiforms的早期历史。该项目的目的是开展一项实地考察活动，以收集更多的材料Semionotus vallejensis，迄今为止代表了一个不完整的保存标本。有了新的材料，该分类群将被详细研究，包括分类学修订和分析其系统发育关系。

Semionotids are among the most important, though less understood basal neopterygian fishes. They represent one of the first and most important radiations of this group, which also includes the teleosts and thus most of the Recent bony fishes. Therefore, knowledge of basal neopterygian phylogenetic relationships and evolution is essential to understand teleost evolution and biodiversity. Since teleosts originated in the late Triassic, the early history of basal neopterygians like the semionotiformes is of special interest. The early fossil record of the semionotiforms is largely biased to the Northern Hemisphere and very little is known about the origin and first radiation of this group in Gondwana. The continental Upper Triassic Cacheuta Formation (Norian) in Argentina has yielded one of the very few records of the group in the Triassic of Gondwana and the only Triassic articulated semionotid remains in South America. This fish, Semionotus vallejensis, thus represents a unique opportunity to have an insight into the early history of semionotiforms in Western Gondwana. The aim of this project is to carry out a fieldwork campaign to collect more material of Semionotus vallejensis, so far represented by a single incompletely preserved specimen. With the new material, the taxon will be studied in detailed, including a taxonomic revision and analysis of its phylogenetic relationships.