DOI: 10.5061/dryad.9360pg2f
title: Data from: Emsian Ammonoidea and the age of the Hunsrück Slate (Rhenish Mountains, Western Germany)

description: The ammonoids from the well-studied German Fossillagerstätte of the
 Hunsrück Slate have the reputation of being the oldest known
 representatives of this cephalopod group. This material is of great
 interest not only because of the global scarcity of the earliest
 ammonoids, but also because it includes the first record of
 stratigraphically-controlled specimens, which could be assigned to the
 middle Kaub Formation in the Bundenbach/Gemünden area. Accordingly, some
 of the Hunsrück Slate ammonoids are indeed the stratigraphically oldest
 ammonoids because they are associated with the index dacryoconarid Nowakia
 praecursor and thus derive from the Nowakia zlichovensis Biozone of the
 early Emsian (Zlíchovian), while younger dacryoconarids and other ammonoid
 samples (Mimagoniatites fecundus, Mimosphinctes tripartitus) indicate the
 Nowakia barrandei to N. elegans biozones. In spite of this special
 importance, these Early Devonian cephalopods have never been revised
 comprehensively.Our study includesmore than 300 Hunsrück Slate specimens
 from both public and private collections. For the first time, ammonoids
 from the Altlay Hunsrück Slate in the Northern Hunsrück/Mosel region are
 reported, while all the materials from older collections derive from the
 middle Kaub Formation of the Central Hunsrück Basin (central Hunsrück,
 Taunus). These early ammonoids thus prove to be a valuable source of
 information for biostratigraphic correlation within the Hunsrück Slate and
 with early Emsian occurrences in other regions. Based on conch characters
 (geometry, ornament, suture lines) and ontogenetic traits, we describe the
 species Metabactrites fuchsi n. sp., Ivoites hunsrueckianus (Erben 1960),
 Ivoites schindewolfi n. sp., ?Ivoites sp., ?Ivoites opitzi n. sp.,
 Anetoceras mittmeyeri n. sp., Erbenoceras advolvens (Erben 1960),
 Erbenoceras solitarium (Barrande 1865), Chebbites sp., Mimosphinctes
 primigenitus (Erben 1965), Mimosphinctes tripartitus Eichenberg, 1931,
 Gyroceratites heinricherbeni n. sp., ?Teicherticeras sp., and
 Mimagoniatites fecundus (Barrande 1865). Supposedly endemic species of the
 Hunsrück Slate such as “Anetoceras recticostatum Erben, 1962” and
 “Mimagoniatites falcistria (Fuchs 1915)” are here synonymized with the
 widely distributed species Erbenoceras solitarium and Mimagoniatites
 fecundus, both known to occur also outside Europe. Furthermore, we studied
 their taphonomy and assigned them to sevengroups of
 preservation.Theresults of this taphonomic study corroborate previous
 interpretations of the depositional environment and diagenesis. We also
 discuss the evolution of the shell in the earliest ammonoids and their
 closest relatives as well as structures (“Opitzian pits”) possibly caused
 by parasitic infestations of these early Emsian ammonoids.
description: List of all studied
 ammonoid specimens from the Hunsrück SlateA excel spreadsheet file
 which contains information (repository number and information, taxonomic
 assignment, locality, stratigraphy, preservation, collection) on all
 studied specimens (as discussed in the text).Hunsruck_AllStudiedSpecimens.xls