Karethraichnus lakkos Zonneveld et al., 2016
|
publication ID |
https://doi.org/ 10.26879/1315 |
|
persistent identifier |
https://treatment.plazi.org/id/03BE87DE-FFFD-FFF7-9A68-F98F41F2F940 |
|
treatment provided by |
Felipe |
|
scientific name |
Karethraichnus lakkos Zonneveld et al., 2016 |
| status |
|
Karethraichnus lakkos Zonneveld et al., 2016
( Figure 3B, C View FIGURE 3 )
Material. Four borings on a plastron (NVP002) and several bowl-shaped pits on three carapaces (NVP003‒005).
Description. Simple shallow, circular to subcircular bores, bowl-shaped pits, sometimes closely spaced, and fused ( Figure 3B View FIGURE 3 ) unbranched shafts into bone borings. They vary in diameter from 0.6 to 6 mm, 1‒4 mm in depth. Depression sides are generally smooth, flattened to rounded.
Discussion. Karethraichnus lakkos represents the third dominant trace fossil in the studied turtle bones. The specimens described show most of the morphological characters of the holotype of K. lakkos as described and illustrated by Zonneveld et al. (2016, p. 6, figure 6.1). This ichnospecies is common on the external surfaces of the plastron and carapaces of the majority of turtle shells. In the present study, K. lakkos appeared in two forms; one of them corresponds to small, unjagged rounded holes, not completely penetrative, apart from each other with varying distances and are not occurring in sets, affecting the external surface of plastron fragments, especially at sulci between epidermal scalesplastron. The second form is slightly larger, consisting of shallow, bowl-shaped pits, closely spaced, and sometimes fused together on the external surfaces of carapace. Borings of the ichnospecies K. lakkos are only located in accessible places in living turtles (in vivo), such as external surfaces of the carapace and plastron, especially at marginal or lip areas. Although K. lakkos was first described from fossil shell bones of geoemydid turtles from lower Eocene non-marine strata of Wyoming (Zonneveld et al., 2016), it was observed also in both terrestrial tortoises and aquatic turtles from the Lower Miocene of Egypt (Zonneveld et al., 2022a).
Producer. Trace makers usually associated with K. lakkos include leeches and ixodid arthropods (ticks), which are known to feed on blood sinuses within shell bone, especially at sulci between epidermal scales (e.g., Siddall and Gaffney, 2004; Zonneveld et al., 2016). However, barnacles attaching onto a bone substrate are also a suggested producer of this ichnotaxon (Zonneveld et al., 2016, 2022b; Collareta et al., 2022).
Stratigraphic and geographic distribution. Campanian of the Qarn Ganah, Kharga Oasis (this study). Karethraichnus lakkos has been recorded from the Lower Eocene of USA (Zonneveld et al., 2016; Adrian et al., 2021), Miocene of Peru, Italy and Egypt (Collareta et al., 2022; Collareta et al., 2023a; Zonneveld et al., 2022a), to Recent (Zonneveld et al., 2022b). This determination extends the stratigraphic range of the taxon at minimum to the Campanian.
Ichnogenus Cubiculum Roberts et al., 2007
Type ichnospecies. Cubiculum ornatus Roberts et al., 2007
Diagnosis. Discrete ovoid borings in bone. Hollow, oval chambers with concave flanks bored into inner spongy and outer cortical bone surfaces. Chamber length three to four times greater than diameter. May be isolated, but observed more commonly in dense, sometimes overlapping concentrations. Walls commonly roughened, composed of shallow, arcuate (apparently paired) grooves (emended after Roberts et al., 2007).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.