Palaeoamyda messeliananov. comb. (Testudines, Pan-Trionychidae) from the Eocene Messel Pit and Geiseltal localities, Germany, taxonomic and phylogenetic insights

Abstract

BackgroundAbundant pan-trionychid (soft-shell) turtles specimens have been found in Eocene sequences of central Europe, particularly from two localities in Germany, the Messel Pit (a UNESCO World Natural Heritage Site) and Geiseltal, traditionally attributed to Trionyx messelianus or Rafetoides austriacus. Over the last two decades new specimens of this taxon from these two localities have been discovered and fully prepared. However, they have remained unstudied, as well as their phylogenetic position inside Pan-Trionychidae is unknown.ResultsFive new specimens of Palaeoamyda messeliana nov. comb. from Messel Pit and Geiseltal localities are fully described here. A revised diagnosis for the species is also presented here, together with its inclusion in a phylogenetic analysis of Pan-Trionychidae that shows that this species is sister to the extant Amyda cartilaginea, one of the most abundant pan-trionychid (soft-shell) turtles from Asia, both members of the clade Chitrini. The specimens described in here are among the best and most complete fossil pan-trionychid skeletons so far known.

The turtles from the upper Eocene, Osona County (Ebro Basin, Catalonia, Spain): new material and its faunistic and environmental context

“…The localities with turtle remains are located in the magnetostratigraphic section of Vic, Vic-Manlleu marls formation. level at which fossil fishes were found (Farrés et al, 2016;Carnevale et al, 2018). The sequence finishes with the deposit of the continental terrestrial siltstones of the Artés Formation (Burbank et al, 1992;Costa, 2011;Costa et al, 2010) (Fig.…”

“…Lignified remains of plants, sponges and invertebrate marks are represented in the Vespella marls member (Farrés, 2003). Osteichthyan fishes were discovered at the base of the Terminal Complex (CT, in Farrés et al, 2016;Carnevale et al, 2018) at a level which is positioned in lateral passage with the Sant Martí Xíc Formation that provided Eocenochelus: this level corresponds to the end of the Eocene marine deposits and is situated just below the continental Artés Formation s. l. (Farrés, 1961(Farrés, , 1993(Farrés, , 2003Farrés and Altimiras, 2007;Farrés and Fierstine, 2009;Staid-Staadt, 1964, 2009;Farrés et al, 2005Farrés et al, , 2016Farrés i Malián, 1960, 2002) (See additive fossils in the series and sedimentology in Farrés et al, 2016. ) All these discoveries highlight the great diversity of fossils from Osona County, deposited in the Ebro Basin and coming from both the littoral zone and the shore of the continental region.…”

Morphological Diversity of Turtle Hyoid Apparatus is Linked to Feeding Behavior

“…28 [2], partially). This is a synapomorphy that can be used to describe pan-trionychids, as it is observable in specimens preserved in the fossil record, such as Palaeoamyda messeliana ( Cadena 2016 ). Unfortunately, most fossil turtles do not preserve the hyoid apparatus (e.g., Cadena and Parham 2015 ; Shao et al.…”