An Abraded Tooth of<i>Edestus</i>(Chondrichthyes, Eugeneodontiformes): Evidence for a Unique Mode of Predation

Itano, Wayne M.

doi:10.1660/062.118.0101

Cited by 4 publications

(7 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Dozens of blades and hundreds of ejected Edestus teeth have been collected from Pennsylvanian age (330 million years ago) marine shale deposits of midwestern United States and Britain, but cranial material is exceedingly rare. In the absence of anatomical context, functional models of Edestus propose comparisons to slashing sawfish rostrums (Eastman, 1902;Hay, 1909), shearing scissor jaws (Peyer, 1968;Zangerl and Jeremiah, 2004), or fixed vertical slashing weapons (Itano, 2014(Itano, , 2015(Itano, , 2018. Hay (1912) described a specimen of Edestus mirus having blades positioned at the jaw symphysis, though only cartilages at the anteriormost site of attachment were preserved.…”

Section: Edestus (Edestidae): a New Type Of Extreme Dentitionmentioning

confidence: 99%

Saws, Scissors, and Sharks: Late Paleozoic Experimentation with Symphyseal Dentition

Tapanila

Pruitt²,

Wilga

et al. 2018

The Anatomical Record

View full text Add to dashboard Cite

Sharks of Late Paleozoic oceans evolved unique dentitions for catching and eating soft bodied prey. A diverse but poorly preserved clade, edestoids are noted for developing biting teeth at the midline of their jaws. Helicoprion has a continuously growing root to accommodate >100 crowns that spiraled on top of one another to form a symphyseal whorl supported and laterally braced within the lower jaw. Reconstruction of jaw mechanics shows that individual serrated crowns grasped, sliced, and pulled prey items into the esophagus. A new description and interpretation of Edestus provides insight into the anatomy and functional morphology of another specialized edestoid. Edestus has opposing curved blades of teeth that are segmented and shed with growth of the animal. Set on a long jaw the lower blade closes with a posterior motion, effectively slicing prey across multiple opposing serrated crowns. Further examples of symphyseal whorls among Edestoidae are provided from previously undescribed North American examples of Toxoprion, Campyloprion, Agassizodus, and Sinohelicoprion. The symphyseal dentition in edestoids is associated with a rigid jaw suspension and may have arisen in response to an increase in pelagic cephalopod prey during the Late Paleozoic.

show abstract

Section: Edestus (Edestidae): a New Type Of Extreme Dentitionmentioning

confidence: 99%

Saws, Scissors, and Sharks: Late Paleozoic Experimentation with Symphyseal Dentition

Tapanila

Pruitt²,

Wilga

et al. 2018

The Anatomical Record

View full text Add to dashboard Cite

show abstract

“…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%

Redefining species concepts for the Pennsylvanian scissor tooth shark, Edestus

Tapanila¹,

Pruitt²

2019

PLoS ONE

View full text Add to dashboard Cite

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.

show abstract

“…Many of the teeth in the sample were considered not useful for this study because the apical parts of the crown were truncated (broken off). In none of the cases in which the crowns were apically truncated was the surface of the remaining part of the crown smoothly polished, as for the Edestus minor tooth described by Itano (2015). Others, e.g., TMM 40234-18 (Figure 4.4), have had much of the outer, hypermineralized layer removed.…”

Section: Initial Survey Of All Teethmentioning

confidence: 99%

“…Macrowear sustained during life has been reported on a tooth of E. minor from the Smithwick Shale (Pennsylvanian, late Atokan = Moscovian) of San Saba County, Texas, USA (Itano, 2015). The apex of the crown is truncated, and the surface of the remaining part is smooth and convex, as if worn by repeated contact with an abrasive surface, such as the skin of a large fish covered with scales or denticles.…”

Section: Introductionmentioning

confidence: 99%

An Abraded Tooth ofEdestus(Chondrichthyes, Eugeneodontiformes): Evidence for a Unique Mode of Predation

Cited by 4 publications

References 9 publications

Saws, Scissors, and Sharks: Late Paleozoic Experimentation with Symphyseal Dentition

Saws, Scissors, and Sharks: Late Paleozoic Experimentation with Symphyseal Dentition

Redefining species concepts for the Pennsylvanian scissor tooth shark, Edestus

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

Contact Info

Product

Resources

About