First fossil records of the <I>tholichthys</I> larval stage of butterfly fishes (<I>Perciformes, Chaetodontidae</I>), from the Oligocene of Europe

Abstract

The first fossils of the <I>tholichthys</I> larval stage of a <I>chaetodontid </I>from the lower Oligocene (Rupelian, Fish Shales; about 30.1 MYA) of Frauenweiler (Baden-Wurttemberg, S Germany) are described, along with two less well-preserved probable <I>tholichthys</I> from the lower Oligocene Menilite-Formation (IPM3, 30-29 MYA and IPM4A, 29-28 MYA) of PrzemyA &gt; l (Outer Carpathians, SE Poland). The fossils are compared with <I>tholichthys</I> larvae of the extant genus of <I>Chaetodontidae</I> to which they are most similar, namely Chaetodon. The German specimens are identified as<I> tholichthys</I> larvae by the plate-like expansions of the supracleithrum and posttemporal that extend posteriorly well behind the head and by an expanded preopercle with a large posterior spine; these bones, and the frontals and supraoccipital, are distinctively rugose. The Polish specimen from IPM3 has similar features so it is safe to assume that it also is a <I>chaetodontid tholichthys</I>, whereas the specimen from IPM4A is so poorly preserved that it can only very tentatively be referred to the <I>Chaetodontidae</I>. The occurrence of tholichthys larvae prompts reconsideration of the paleoenvironmental situation at their respective fossil sites.