Bohemicardia hainense (Maurer) revisted: insights into ontogeny and variability of a Devonian hippocardiid rostroconch (Conocardiida: Hippocardiidae)

Abstract

Re-examination of type material and abundant specimens enable the reinstatement of ‘Conocardium hainense Maurer, 1885’, a species erroneously synonymised with Babinicardia clathrata by Rogalla and Amler. Based on the completely reconstructed morphology, C. hainense can be assigned to the genus Bohemicardia within the Hippocardiidae of the Hippocardioidea. About 600 specimens from a single locality available for study including a wide range of ontogenetic stages allow documentation of allometric growth, with shell width increasing faster than shell height. Protoconchs are not preserved, leaving the development from larval stages to early juveniles unrecorded. The large number of specimens confirms a rather narrow range of morphological variation within the taxon. Based on the preservation of the rarely observed external shell layer, conclusions on shell shape, presence of a hood and external shell ornamentation of the taxon are possible. The material confirms that recognising different shell layer architecture in conocardiid rostroconchs is a prerequisite for specific identification and basic taxonomy.