Oriented microwear on a tooth of Edestus minor (Chondrichthyes, Eugeneodontiformes):  Implications for dental function

Itano, Wayne M.

doi:10.26879/831

Cited by 4 publications

(4 citation statements)

References 28 publications

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“…triserratus and E . minor have whorls that exhibit a greater degree of curvature, leading Itano [8, 38, 39, 40] to imagine the whorls to curl outside the mouth for a vertical slashing motion. The evidence used for this hypothesis include several specimens of Edestus teeth showing wear patterns that are predominantly transverse to the crown (i.e., parallel to the base) [38, 39, 40].…”

Section: Resultsmentioning

confidence: 99%

“…minor have whorls that exhibit a greater degree of curvature, leading Itano [8, 38, 39, 40] to imagine the whorls to curl outside the mouth for a vertical slashing motion. The evidence used for this hypothesis include several specimens of Edestus teeth showing wear patterns that are predominantly transverse to the crown (i.e., parallel to the base) [38, 39, 40]. This wear pattern is entirely consistent with the anatomy and functional reconstruction of FMNH PF 2204 [2], showing that Edestus whorls were positioned in opposition inside the mouth, and that the biting motion involved anterior-posterior slicing with the lower whorl.…”

Section: Resultsmentioning

confidence: 99%

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Redefining species concepts for the Pennsylvanian scissor tooth shark, Edestus

Tapanila¹,

Pruitt²

2019

PLoS ONE

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This study reevaluates the tooth morphology used to define species within the genus Edestus (Chondrichthyes, Euchondrocephali). Known as the scissor tooth shark, Edestus produced a unique dentition of spiraled tooth families positioned in the symphysis (midline) of the upper and lower jaws. Morphometric analysis of more than 200 ejected teeth and intact spiral tooth whorls demonstrates that teeth from the upper and lower whorls differ in shape and ontogeny. Comparison of these data to the type specimens of 13 existing species reduces the number of morphologically distinct Edestus to just four species and refines the stratigraphic occurrence and expansion of the group. E . triserratus has a narrow bullet-shaped crown that points anteriorly and has roots of intermediate length. E . minor crowns have a wider triangular base, whereas the crowns of E . heinrichi form nearly equilateral triangles and are supported by an elongated root. E . vorax , which also has roughly equilateral triangular crowns, has short and deep roots, and is only known from very large specimens that are distinct from the growth series of E . heinrichi . Tooth and whorl morphologies among the species are consistent with cranial anatomy observed in a juvenile E . heinrichi and with transverse tooth-wear patterns to suggest Edestus used a forward to backward slicing motion to bite its prey. Extrapolating body size from tooth whorl length provides a conservative estimate that E . heinrichi could exceed 6.7 m in length. Edestus fossils are recovered from coastal marine to estuarine deposits spanning roughly six million years (313–307 Ma). Edestus first appears in England during the latest Bashkirian (313 Ma, Carboniferous), a few million years after its most closely resembling genus Lestrodus . Diversification and range expansion of Edestus coincides with the Moscovian transgression that flooded Laurentia and the Russian platform.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Redefining species concepts for the Pennsylvanian scissor tooth shark, Edestus

Tapanila¹,

Pruitt²

2019

PLoS ONE

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“…Galeocerdo cuvier's serrated teeth are suitable for cracking hard prey, as well as for cutting though flesh (Ferrara et al, 2011). The latter feeding is hypothesized as a potential reason for several scratches on Edestus minor teeth (Itano, 2019), therefore, it could potentially cause also furrows on the dental surface on G. cuvier. Galeocerdo cuvier has the most opportunistic diet of all investigated shark species, including fish, marine mammals, birds, as well as carrion and even garbage into its diet (Table 2).…”

Section: Suitability Of Dental Surface Texture On Shark Teeth For Die...mentioning

confidence: 99%

“…McLennan also postulates that there is diet-related antemortem wear preserved on fossil Carcharodon carcharias and Carcharocles megalodon teeth. Similarly, a 2D microwear study using stereomicroscopy to count the number of ante-mortem scratches on fossil teeth of the Carboniferous shark Edestus minor found a relationship between abundance and orientation of scratches near the tooth apex to hunting and feeding behaviour (Itano, 2019).…”

Section: Introductionmentioning

confidence: 96%

Dental microwear texture analysis on extant and extinct sharks: Ante- or post-mortem tooth wear?

Weber

Winkler

Kaiser

et al. 2021

Palaeogeography, Palaeoclimatology, Palaeoecology

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Testing dental microwear as a proxy for characterising trophic ecology in fossil elasmobranchs (chondrichthyans)

Paredes-Aliaga,

Botella,

Romero

2024

Swiss J Palaeontol

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Dental microwear analysis is a well-established technique that provides valuable information about the diets of extant and extinct taxa. It has been used effectively in most major groups of vertebrates. However, in chondrichthyans, these methods have been implemented only recently in the form of dental microwear texture analysis, with conflicting results. Causes intrinsic to chondrichthyan biology, such as limited food-to-tooth contact, low diversity in terms of trophic categories or fast tooth replacement, have been suggested to reduce diet-related wear on individual teeth, hindering the use of this approach for reliable dietary reconstruction. Here, we explored the relationship between diet and dental microwear in chondrichthyans by using 2D analysis, which can provide finer-scale identification and accurate definition of scratch morphology from tooth surfaces a priori. Scratches were counted and measured on the teeth of 34 extant elasmobranchs grouped into three categories (piscivorous, durophagous and generalist) according to dietary preferences. Our results revealed specific patterns of tooth microwear as a function of dietary abrasiveness, enabling the discrimination of trophic groups and thus establishing a useful comparative framework for inferring aspects of trophic ecology in fossils. We then used this information to study dental microwear in six fossil species from the same locality and stratigraphic levels. First, analyses of the enameloid surfaces of the fossil show that post-mortem alterations are distinguishable, allowing reliable quantification of diet-related ante-mortem microwear signatures. Discriminant analysis allowed the recognition of microwear patterns comparable to those of living sharks and linked them to specific trophic groups with high probability levels (> 90%). Thus, microwear features developing on chondrichthyan teeth during feeding are intense enough to retain information regarding diet preferences. 2D microwear analysis can track this information, proving to be a useful tool for providing significant information not only about diet but also about oral processing mechanisms in extinct chondrichthyans.

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Oriented microwear on a tooth of Edestus minor (Chondrichthyes, Eugeneodontiformes): Implications for dental function

Cited by 4 publications

References 28 publications

Redefining species concepts for the Pennsylvanian scissor tooth shark, Edestus

Redefining species concepts for the Pennsylvanian scissor tooth shark, Edestus

Dental microwear texture analysis on extant and extinct sharks: Ante- or post-mortem tooth wear?

Testing dental microwear as a proxy for characterising trophic ecology in fossil elasmobranchs (chondrichthyans)

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