Maxwell Erin E, López-Arbarello Adriana
Staatliches Museum für Naturkunde Stuttgart, Stuttgart, Germany.
Department of Earth- and Environmental Sciences, Palaeontology and Geobiology, and GeoBio-Center, Ludwig-Maximilians-Universität München, Munich, Germany.
PeerJ. 2018 Jun 27;6:e5033. doi: 10.7717/peerj.5033. eCollection 2018.
is one of the most abundant and diverse genera of ganoid fishes from the Early Jurassic fossil lagerstätte of Europe. In spite of its abundance, however, its timing of extinction is poorly constrained, with the youngest described material being Early Jurassic in age. We describe new diagnostic and relatively complete material of a large species of (standard length estimated at 50 cm) from the Middle Jurassic (earliest Aalenian) Opalinuston Formation of Baden-Württemberg, Germany. The Aalenian material represents a distinct species, sp. nov., differing from Early Jurassic species in a unique combination of characters pertaining to the shape of the dermal skull elements, pectoral fin position, and scale shape and ornamentation. However, although sp. nov. exhibits a unique combination of characters, there are no autapomorphies with which to distinguish it from the Toarcian species of . represents the geologically youngest species of , extending the range of this genus into the Middle Jurassic. The Opalinuston Formation fills an important gap in the marine vertebrate fossil record, and finds from this horizon have the potential to greatly improve our understanding of evolutionary dynamics over this period of faunal transition.
是欧洲早侏罗世化石库中最丰富多样的硬鳞鱼类属之一。然而，尽管它数量众多，但其灭绝时间却受到的限制很少，已知最年轻的化石材料来自早侏罗世。我们描述了一种来自德国巴登 - 符腾堡州中侏罗世（最早的阿连阶）奥帕林斯顿组的大型（标准长度估计为50厘米）的新的具有诊断意义且相对完整的材料。阿连阶的材料代表了一个独特的物种，新物种，它在与真皮头骨元素形状、胸鳍位置以及鳞片形状和纹饰相关的特征的独特组合上与早侏罗世物种不同。然而，尽管新物种展现出独特的特征组合，但没有可将其与托阿尔阶物种区分开来的自近裔性状。新物种代表了该属地质上最年轻的物种，将该属的范围扩展到了中侏罗世。奥帕林斯顿组填补了海洋脊椎动物化石记录中的一个重要空白，从这一层位的发现有可能极大地增进我们对这一动物群过渡时期进化动态的理解。
