On the taphonomy of the late Maastrichtian (Late Cretaceous) marine turtle Allopleuron hofmanni

Abstract

An exhaustive screening of public collections containing remains of the latest Cretaceous (late Maastrichtian) marine turtle Allopleuron hofmanni (Gray, 1831) from the type area of the Maastrichtian Stage (southeast Netherlands, northeast Belgium) shows the available material to represent almost exclusively adult individuals. The various skeletal elements are not preserved in proportionally equal abundance, with portions of carapace, pectoral girdle, cranium and mandible overrepresented. These observations can be explained by population characteristics and taphonomic factors. During the late Maastrichtian, while hatchlings and juveniles in all likelihood lived and fed elsewhere, extensive seagrass meadows might have supported a population of only adult marine turtles.

The shell bone histology of fossil and extant marine turtles revisited

“…Instead, it retains a very thick, well vascularized external and a very thin internal cortex, similar to the general make‐up of the ossicles of the dermochelyoid turtle Psephophorus polygonus (Delfino et al ., ). A taphonomic study on A. hofmanni by Janssen, van Baal & Schulp (: 191) revealed that all known specimens of this species are adults, which led to the hypothesis that the ‘adult individuals inhabited the coastal, shallow environment of the Maastrichtian type area, whereas hatchlings and juveniles lived elsewhere, in yet unknown habitats’, similar to the biphasic lifestyle (neritic versus pelagic) of some modern cheloniids (e.g. C. caretta ; Bolten, ).…”

A tribute to the late Felder brothers – pioneers of Limburg geology and prehistoric archaeology; introduction

“…Most of these skeletal remains can be ascribed to Allopleuron hofmanni (Gray, 1831), the commonest species in the area. Despite its regular occurrence, there still remains a lot to be discovered, as the contribution by Janssen et al (2011) shows.…”

A new species of dercetid (Teleostei, Aulopiformes) from the type Maastrichtian of southern Limburg, the Netherlands

“…The top of the food chain was occupied by mosasauroids, the largest marine reptiles of this time interval, with overall lengths in excess of 16 m (Lingham-Soliar, 1995;Gallagher et al, 2004;Street & Caldwell, 2016). Other associated reptiles included plesiosaurs (Mulder et al, 2000), crocodiles (Mulder et al, 1998(Mulder et al, , 2016 and turtles (Mulder, 2003;Janssen et al, 2011). In addition, a fairly wide array of small to medium-sized cartilaginous fish such as sharks, rays, skates and sawfish (Elasmobranchii) and chimaeras (Holocephali) was represented (Herman, 1977;Duffin & Reynders, 1995), as well as various species of ray-finned fish (Actinopterygii) (Friedman, 2012), in particular in the upper Gulpen Formation and the entire Maastricht and Kunrade formations.…”