ABSTRACT

New material from the Upper Devonian (Famennian) Catskill Formation of Pennsylvania, U.S.A., indicates the presence of a new species of Megalichthys. A large collection of complete and well-preserved fossil material from the Red Hill field locality enables a thorough anatomical description that is not commonly available in Megalichthyidae. The cranial material includes skull roof, partial cheek, lower jaw, opercular-gular elements, palatoquadrate, and dermal palatal elements. The postcranial material includes pectoral fin elements including cleithrum, mesomeres, and lepidotrichia; pelvic fin including lepidotrichia; and body scales in articulation. The new species is distinguished from other species of Megalichthys by the presence of a pineal series of bones, a triangular-shaped principal gular, and a lack of sensory canal pores on the postparietal. We review the taxonomic history and status of Megalichthyidae and Megalichthys and provide revised diagnoses for each that include only discrete features demonstrated to be sufficient for taxonomic assignment. We discuss additional cosmine-covered osteolepiform fossils from other Catskill Formation exposures. These include the type and only specimen of Sterropterygion brandei and seven new specimens (including a partial snout, a partial parietal shield, a partial postparietal shield, a partial cheek, and complete lower jaws) that potentially represent megalichthyid species in addition to the one at the focus of this study. With this description of new megalichthyid material, the Catskill Formation continues to produce, in some cases, the only known Devonian occurrence of otherwise younger taxa.

摘要

美国宾夕法尼亚上泥盆纪（Famennian）卡茨基尔组的新物质表明存在一种新的巨of。来自红山野外的大量完整且保存完好的化石材料的收集，提供了完整的解剖学描述，这在巨Mega科中是不常见的。颅骨材料包括颅骨顶，部分脸颊，下颌，舌状胆囊元件，掌qua和真皮pa成分。颅后材料包括胸鳍元素，包括韧皮部，减数分裂和鳞翅目毛虫。骨盆鳍，包括鳞翅目鱼类；和人体秤的关节。新物种区别于其他巨li属由于存在松果体系列的骨骼，三角形的主卵形壁和顶壁上缺少感觉管孔。我们回顾了巨鳞甲科和巨鳞甲科的分类历史和地位，并为每种分类提供了经过修订的诊断，这些诊断仅包括证明足以用于分类学分配的离散特征。我们讨论了其他卡茨基尔形成群暴露的其他被胭脂红覆盖的骨鳞状化石。其中包括直翅目夜蛾的类型和唯一标本除本研究重点外，还有七个新标本（包括部分口鼻部，部分顶盾，部分顶后盾，部分脸颊和完整的下颌），可能代表甲藻类。通过对新甲藻类物质的描述，卡茨基尔组在某些情况下继续产生泥盆纪唯一已知的其他较年轻的类群。