Machichnus? bohemicus Mikuláš et al., 2006
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publication ID |
https://doi.org/ 10.26879/1315 |
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persistent identifier |
https://treatment.plazi.org/id/03BE87DE-FFF3-FFFA-9A6A-FE584532F8B7 |
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treatment provided by |
Felipe |
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scientific name |
Machichnus? bohemicus Mikuláš et al., 2006 |
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Machichnus? bohemicus Mikuláš et al., 2006
( Figure 4H View FIGURE 4 )
Material. Three parallel scratches on a carapace remain (NVP030).
Diagnosis. Shallow, thin, discrete, parallel to subparallel, smooth-bottomed scratches. The scratches occur in small groups or series of corresponding width and length; width typically reaches 0.2–1.0 mm and usual length is up to 10 mm ( Mikuláš et al., 2006).
Description. Shallow, thin, discrete, parallel to subparallel scratches. At the studied site, they occur on cortical bone of long bones or on the surfaces of antlers. The scratches occur in small groups. Within the series, they typically cover 10– 50% of the surface. Each individual scrape is very short and does not overlap or approach any adjacent scrape. Length for each individual mark is typically greater (average 0.65 mm) than width. Each pair is approximately one millimetre apart.
Remarks. Scratches of the given morphology most likely occur during the feeding activity on soft tissues surrounding the bones. In the case of antlers, the scratches are interpreted as gnawing traces, as there is no digestible tissue to be consumed, except the felt on young antlers.
Discussion. The ichnofamily Machichnidae is characterised by a set of grooves, with somewhat irregular outlines on the cortical bone. This family is represented by five distinctive ichnogenera: Machichnus , Nihilichnus, Linichnus, Knethichnus , and Mandaodonites . Chumakov et al. (2013) erected three new ichnospecies, namely Machichnus normani , M. harlandi , and M. jeansi , for scratches on phosphorite nodules and pebbles from the Upper Cretaceous of England. Herein, the presence of shallow, thin, discrete, parallel to subparallel scratches that occur in small groups or series are undoubtedly assigned to the ichnogenus Machichnus . However, because of the smaller dimensions of each pair than the holotype of M. bohemicus described by Mikuláš et al. (2006), their ichnospecific determination is uncertain and needs more additional, well-preserved specimens to be confirmed.
Producer. The ichnospecies Machichnus bohemicus is interpreted as a biting trace, possibly made by crocodylians ( Mikuláš et al., 2006; Mikuláš and Dvořák, 2010). This ichnospecies is suggested to be produced by mechanical action of carnivore teeth (e.g., fishes and crocodiles) on the bones (Bieńkowska-Wasiluk et al., 2013; Irazoqui and Acosta Hospitaleche, 2022).
Stratigraphic and geographic distribution. Campanian of the Qarn Ganah, Kharga Oasis (this study). Machichnus bohemicus has been recorded from the Middle Danian (Lower Palaeocene) of Denmark ( Milàn et al., 2011), Eocene of West Antarctica ( Irazoqui and Acosta Hospitaleche, 2022) and Miocene of Czech Republic ( Mikuláš et al., 2006). This determination extends the stratigraphic range of the ichnotaxon through at minimum the latest Maastrichtian. In addition, Mujal et al. (2022) identified bite traces on tetrapod bones from the Middle Triassic of Southwestern Germany that were identified as Machichnus -like traces.
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