TABLE 1. The studied bioerosional ichnotaxa reported on the turtle remains, stratigraphic range, impacted surface(s), their producers and ethological categories. * ‒ ichnotaxa recorded for the first time in Egypt.
| Trace fossil | Stratigraphic range | Impacted surface(s) | Trace makers | Ethological category | |
| 1. | Nihilichnus nihilicus Mikuláš et al., 2006 (Figure 3A) |
Middle Triassic‒Lower Palaeocene | Carapace | Scavengers and predators (Milàn et al., 2011) | Praedichnia (predation or scavenging traces) |
| 2. | Karethraichnus lakkos Zonneveld et al., 2016 (Figure 3B, C) |
Campanian (this study)‒Recent | Carapace and Plastron | Multiple trace makers may produce similar traces (the ectoparasites ticks, barnacles (Zonneveld et al., 2016) |
Fodinichnia |
| 3. | * Cubiculum ornatus Roberts et al., 2007 (Figure 3D, E) |
Middle Jurassic‒Pleistocene | Carapace | Larvae of dermestid beetles (Kitching, 1980; Martin and West, 1995; Hasiotis et al., 1999; Ozeki et al., 2020; Perea et al., 2020) | Pupichnia |
| 4. | * Cubiculum inornatus (Xing et al., 2015) (Figure 3D, F) |
Campanian (this study)‒Middle Triassic | Carapace | Indeterminate osteophagous insect (Xing et al., 2015; Paes Neto et al., 2016) |
Pupichinia |
| 5. | * Cubiculum isp. (Figure 3G, Figure 4F) |
Campanian (this study) | Carapace | Dermestid beetles | Pupichnia |
| 6. | * Osteocallis mandibulus Roberts et al., 2007 (Figure 3D, H, Figure 4A, B) |
Upper Triassic‒Lower Pliocene | Carapace | Feeding by osteophagous insects produced by silphid and histerid beetles (Roberts et al., 2007) |
Fodinichnia |
| 7. | Radulichnus inopinatus Voigt, 1977 (Figure 4C, D) |
Middle Devonian‒Pleistocene | Carapace | Gastropods and polyplacophorans (chitons) (Voigt, 1977; Jagt, 2003; Gibert et al., 2007; Lopesa and Pereira, 2019; Collareta et al., 2023a) |
Pascichnia |
| 8. | * Osteichnus ossiobontum (Thenius, 1988a) (Figure 4E) |
Upper Jurassic‒Upper Miocene | Carapace | Attributed to osteophagous insects nymphs of mayflies (Thenius, 1988a) |
Fodinichnia |
| 9. | * Osedacoides jurassicus Karl et al., 2012 (Figure 4F) |
Upper Jurassic‒Campanian (this study | Carapace | Osteophagous polychaetes (Karl et al., 2012) | Fodinichnia |
| 10. | * Sulculites bellus Vialov and Nessov, 1974 (Figure 4G) |
Albian‒Campanian (this study) | Carapace | Unknown organisms, may be worms | Fodinichnia |
| 11. | * Machichnus ? bohemicus Mikuláš et al., 2006 (Figure 4H) |
Campanian (this study)‒Lower Palaeocene | Carapace | Rodent probably teeth of fishes and crocodile (Mikuláš et al., 2006; Mikuláš and Dvořák, 2010) |
Praedichnia (predation or scavenging traces) |
