New Eocene Coleoid (Cephalopoda) Diversity from Statolith Remains: Taxonomic Assignation, Fossil Record Analysis, and New Data for Calibrating Molecular Phylogenies

Abstract

New coleoid cephalopods are described from statolith remains from the Middle Eocene (Middle Lutetian) of the Paris Basin. Fifteen fossil statoliths are identified and assigned to the Sepiidae (Sepia boletzkyi sp. nov.,? Sepia pira sp. nov.), Loliginidae (Loligo clarkei sp. nov.), and Ommastrephidae (genus indet.) families. The sediments containing these fossils indicate permanent aquatic settings in the infralittoral domain. These sediments range in age from 46 Mya to 43 Mya. Analysis of the fossil record of statoliths (from findings described here, together with a review of previously published data) indicates marked biases in our knowledge. Fossil statoliths are known from as far back as the Early Jurassic (199.3 to 190.8 Mya) but surprisingly, to the best of our knowledge, no record occurs in the Cretaceous. This is a “knowledge bias” and clearly calls for further studies. Finally, we attempt to compare findings described here with fossils previously used to constrain divergence and/or diversification ages of some coleoid subclades in molecular phylogenies. This comparison clearly indicates that the new records detailed here will challenge some estimated divergence times of coleoid cephalopod subclades.

Buoyancy mechanisms limit preservation of coleoid cephalopod soft tissues in Mesozoic Lagerstätten

“…; Neige et al . ) frequently found fossilized worldwide. Conversely, coleoid soft tissues are preserved in only a handful of Mesozoic and Cenozoic Lagerstätten (Fig.…”

Seagrass and cuttlefish—an historic association

“…Belosaepia sepioides was reported from offshore shale of the Ilaro Formation (Lutetian) overlying the Paleocene of south-western Nigeria from a diverse fauna lacking seagrass indicators (PDB 77257). Neige et al (2016) recorded coleoid statoliths from the middle Lutetian (middle Eocene) of Thiverval-Grignon (Paris Basin, France). They erected two new species, Sepia boletzkyi and ?Sepia pira for statoliths from beds 3b (clayey limestone) and 4a (glauconitic, calcareous sand) at the Thiverval-Grignon section.…”

“…have indicated that buoyancy mechanisms may limit cephalopod soft tissue preservation and may have implications for lack of fossilised cuttlefish. The record of Sepia statoliths from the middle Lutetian (middle Eocene) of Thiverval-Grignon (Paris Basin, France) (Neige et al, 2016) infers that the cuttlebone has gone and that soft parts have disintegrated or been eaten leaving only the aragonitic statoliths to be preserved.…”

“…Fossil cuttlefish are comparatively rare, consisting of the cuttlebone or its fragments. There is a single record of cuttlefish statoliths from the middle Eocene of France (Neige et al, 2016). Part of this rarity may be due to the fibrous, aragonitic nature of the cuttlebone (Checa et al, 2015) as well as preservational conditions.…”

New regulatory tool for the conservation of the geological heritage in France: the Prefectural Decree of the Protection of the Geotope (APPG). Application and feedback in the Yvelines department (Paris basin, Île-de-France)

“…Even though the inventory is highly thorough, new species may still be found. In 2016, statoliths of Sepia (cuttlefish) and Loligo (squid) found in the fossil site allowed to identify three new species (Neige et al, 2016). These are the oldest fossils of cuttlefish and squid found in the world.…”