Ectoparasite borings, mesoparasite borings, and scavenging traces in early Miocene turtle and tortoise shell: Moghra Formation, Wadi Moghra, Egypt

John-Paul Zonneveld,Mohamed K Abdelgawad,Ellen R Miller

doi:10.1017/jpa.2021.92

John-Paul Zonneveld, Mohamed K Abdelgawad + Show 1 more

Open Access

https://doi.org/10.1017/jpa.2021.92

Copy DOI

Abstract

AbstractBorings and bite marks on fossil turtle carapaces and plastra from the Miocene Moghra Formation, northern Egypt, are herein described. All fossil turtle material from Moghra exhibits ichnofossils. The positions of invertebrate borings on external surfaces of tortoise and turtle shell material at Moghra are consistent with the activities of ectoparasites or mesoparasites.A single invertebrate ichnotaxon, Karethraichnus lakkos Zonneveld et al., 2016, occurs on Moghra tortoise fossils. This trace fossil was likely emplaced by ixodid arthropods (ticks). Bite marks assigned to Nihilichnus occur on a carapace peripheral and are interpreted to reflect postmortem scavenging. An abundant and moderately diverse assemblage of invertebrate borings characterizes Moghra aquatic turtle shells. Karethraichnus lakkos and Thatchtelithichnus holmani Zonneveld et al., 2016 traces on aquatic turtles are interpreted to reflect leech and/or trematode parasitism. Gunnellichnus moghraensis (new ichnogenus new ichnospecies) and G. akolouthiste (n. isp.) likely reflect bacterial and/or fungal infections on aquatic turtle shells that rarely dried out.UUID: http://zoobank.org/f0a3977d-deff-4954-b196-536adc405854

Highlights

Bone-modification features are common on Mesozoic and Cenozoic vertebrate fossils and are an essential source of insight into the ecology and taphonomy of their host organisms (e.g., Behrensmeyer, 1978; Behrensmeyer et al, 1979; Fiorillo, 1987; 1990; Tappan, 1994; Hasiotis; 2004; Tapanila et al, 2004; Mikulás et al, 2006; Roberts et al, 2007; Zonneveld et al, 2016)
The epidermal layer protects the bone from damage incurred by interaction of the host organism with its environment, this layer can be penetrated or bypassed by parasites and the bone modified while the host organism remains alive (Zonneveld et al, 2016)
Many of these trace fossils were likely emplaced before the death of the host organism

Summary

Introduction

Bone-modification features are common on Mesozoic and Cenozoic vertebrate fossils and are an essential source of insight into the ecology and taphonomy of their host organisms (e.g., Behrensmeyer, 1978; Behrensmeyer et al, 1979; Fiorillo, 1987; 1990; Tappan, 1994; Hasiotis; 2004; Tapanila et al, 2004; Mikulás et al, 2006; Roberts et al, 2007; Zonneveld et al, 2016). Vertebrate scavenging and predation activities result in tooth marks, scratch marks, and crushing of bone (e.g., Behrensmeyer, 1978; Behrensmeyer et al, 1979: Mikulás et al, 2006) whereas invertebrate scavenging can result in grooves, pits, lesions, and etchings (e.g., Rogers, 1992; Kaiser, 2000; Paik, 2000; Britt et al, 2006; Roberts et al, 2007; Cabral et al, 2011). Extensive data are available on modern reptile, and in particular turtle, pathologies (e.g., Tasnádi-Kubacska, 1962; Wells, 1964; Jacobson, 2007; Rothschild, 2009; Rothschild et al, 2012, 2013) These contributions, invaluable, focus primarily on pathologies of nonskeletonized material, somewhat complicating their application to taphonomic and ichnological investigations of fossil material. Lacking in the literature are descriptions and illustrations of nonpathological bone modification features such as pits, holes, and lesions caused by invertebrate parasites

Methods

Discussion

Conclusion