Osteichnus ossiobontum ( Thenius, 1988a )

Hedeny, Magdy El, Mohesn, Sara, Tantawy, Abdel-aziz, El-Sabbagh, Ahmed, AbdelGawad, Mohamed & El-Kheir, Gebely Abu, 2023, Bioerosion traces on the Campanian turtle remains: New data from the lagoonal deposits of the Quseir Formation, Kharga Oasis, Egypt, Palaeontologia Electronica (a 40) 26 (3), pp. 1-21 : 10

Osteichnus ossiobontum ( Thenius, 1988a)

( Figure 4E )

Material. Up to 25 borings on a carapace remain (NVP022).

Description. Cylindrical non-branched parallel borings with fused U-notches, inclined to the bone surface, cross-section long-oval at deeper levels with smooth interior surface. Dimensions vary between 3–8 mm long and between 1–3 mm in width. Depth of borings is ~ 2–3 mm.

Discussion. The specimens resemble the type ichnospecies Asthenopodichnium ossibiontum as described and illustrated by Thenius (1988a, p. 9, pl. 3, figures 1, 2) from the Miocene of Austria. The lithic-boring Rogerella Saint-Seine (1951) has closely similar features to the present osteic skeletal substrates ichnogenus. Unlike the producer of the present ichnogenus, barnacles of the Order Acrothoracica are considered to be the trace makers of Rogerella (e.g., Mikuláš, 1992).

Producer. Asthenopodinae mayfly larvae ( Thenius, 1988a, 1988b; Britt et al., 2008; Ozeki et al., 2020). In particular, the Asthenopodinae mayfly larvae, a subfamily of Polymitarcyidae , have been assigned to be the producer of the present ichnospecies ( Thenius, 1979, 1988a; Jalvo and Andrews, 2016; Genise, 2017). Nowadays, species of this family live in moderate to high energy fluvial systems (Barber-James et al., 2008).

Stratigraphic and geographic distribution. Campanian of the Qarn Ganah, Kharga Oasis (this study). Upper Jurassic of USA (Britt et al., 2008) to Middle‒Upper Miocene of Austria ( Thenius, 1988a, 1988b).

Ichnogenus Osedacoides Karl et al., 2012

Type ichnospecies. Osedacoides jurassicus Karl et al., 2012

Diagnosis. Simple, basally thickened to branched borings in marine vertebrate bones with a single opening to the surface ( Karl et al., 2012).

Figures

FIGURE 4. (A, B) Osteocallis mandibulus. (A) Small randomly oriented surface borings. (B) Close up view of A, showing small randomly oriented surface borings. (C, D) Radulichnus inopinatus, parallel to sub-parallel arcuate bundles closely spaced in groups. (E) Osteichnus ossiobontum, parallel borings with fused U-notches, inclined to the bone surface. (F) Osedacoides jurassicus, small simple borings in bone (yellow arrows) penetrating into the turtle bone. Note the occurrence of some Cubiculum isp. traces (red arrows). (G) Sulculites bellus, smooth, slender narrow, nonbranched straight to curved grooves. (H) Machichnus?bohemicus, shallow serial parallel or subparallel grooves (arrows) in carapace peripheral. Scale bars equal 1.0 cm, except for B, D, and E, which are 0.5 cm.