Hypanus heterodontus
Cicimurri, Ebersole, Stringer, Starnes & Phillips, 2025
Classification: Elasmobranchii Myliobatiformes Dasyatidae
Reference of the original description
Late Oligocene fishes (Chondrichthyes and Osteichthyes) from the Catahoula Formation in Wayne County, Mississippi, USA. European Journal of Taxonomy, 984(1), 1–131
Late Oligocene fishes (Chondrichthyes and Osteichthyes) from the Catahoula Formation in Wayne County, Mississippi, USA. European Journal of Taxonomy, 984(1), 1–131
Types
Hypanus heterodontus
Holotype: SC: 2013.28.449; Paratype: SC: 2013.28.406; SC: 2013.28.409; SC: 2013.28.444;
Hypanus heterodontus
Holotype: SC: 2013.28.449; Paratype: SC: 2013.28.406; SC: 2013.28.409; SC: 2013.28.444;
Images of types
Description:
Citation: Hypanus heterodontus Cicimurri, Ebersole, Stringer, Starnes & Phillips, 2025: In: Database of fossil elasmobranch teeth www.shark-references.com, World Wide Web electronic publication, Version 09/2025
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Hypanus heterodontus Cicimurri, Ebersole, Stringer, Starnes & Phillips, 2025; low-crowned teeth. A–E. SC2013.28.461. A. Labial view. B. Occlusal view. C. Lingual view. D. Basal view. E. Profile view. F–J. SC2013.28.437. F. Labial view. G. Occlusal view. H. Lingual view. I. Basal view. J. Profile view. K–O. SC2013.28.440. K. Labial view. L. Occlusal view. M. Lingual view. N. Basal view. O. Profile view. P–T. SC2013.28.445. P. Labial view. Q. Occlusal view. R. Lingual view. S. Basal view. T. Profile view. U–Y. SC2013.28.455. U. Labial view. V. Occlusal view. W. Lingual view. X. Basal view. Y. Profile view. Z–DD. SC2013.28.450. Z. Labial view. AA. Occlusal view. BB. Lingual view. CC. Basal view. DD. Profile view. Scale bars = 1 mm. From Cicimurri et al. (2025)
Hypanus heterodontus Cicimurri, Ebersole, Stringer, Starnes & Phillips, 2025; low-crowned teeth. A–E. SC2013.28.461. A. Labial view. B. Occlusal view. C. Lingual view. D. Basal view. E. Profile view. F–J. SC2013.28.437. F. Labial view. G. Occlusal view. H. Lingual view. I. Basal view. J. Profile view. K–O. SC2013.28.440. K. Labial view. L. Occlusal view. M. Lingual view. N. Basal view. O. Profile view. P–T. SC2013.28.445. P. Labial view. Q. Occlusal view. R. Lingual view. S. Basal view. T. Profile view. U–Y. SC2013.28.455. U. Labial view. V. Occlusal view. W. Lingual view. X. Basal view. Y. Profile view. Z–DD. SC2013.28.450. Z. Labial view. AA. Occlusal view. BB. Lingual view. CC. Basal view. DD. Profile view. Scale bars = 1 mm. From Cicimurri et al. (2025)
Description
Original diagnosis after Cicimurri, Ebersole, Stringer, Starnes & Phillips (2025) p. 54-55 [34348]: Low-crowned teeth and high-crowned teeth are represented for this taxon. Low-crowned teeth generally have a convex labial face (amount of convexity varies) with a transversely depressed area near the apex. The labial face bears highly irregular ridges that are weakly to strongly developed and extend onto a wide transverse crest. The lingual face is smooth and bears a medial longitudinal crest flanked by lateral depressed areas. The bilobate root is low, located closer to, and extending beyond, the lingual crown margin. High-crowned teeth are cuspidate, with cusp height and degree of distal and lingual inclination varying. A thin transverse crest subdivides the crown into a large lingual face and much smaller labial face. The labial face may be virtually smooth but is usually ornamented with irregular and disconnected vertical ridges, sometimes forming a reticulated network. The lingual face is smooth and exhibits a medial longitudinal crest of varying width. New fossil species of Hypanus have yet to be named, but fossil teeth of several extant species (formerly placed in Dasyatis) have been reported. A small male tooth identified as H. americanus (Hildebrand & Schroeder, 1928) from the lower Miocene Pungo River Formation of North Carolina has a much more concave labial face and the lingual crown curvature is more pronounced apically than on Hypanus? heterodontus sp. nov. teeth of similar stature (Purdy et al. 2001). However, this comparison may be irrelevant, as we believe the Miocene tooth is that of a mobulid ray. Fitch (1966, 1970) reported a total of 12 H. dipterurus (Jordan & Gilbert, 1880) teeth from Pleistocene deposits of California, but he did not describe or illustrate them. Deynat & Brito (1994) reported caudal spines of H. guttatus (Bloch & Schneider, 1801) from the Miocene of central South America, but no teeth were noted. Pliocene teeth from the Yorktown Formation of North Carolina identified as H. say (Lesueur, 1817) by Purdy et al. (2001) are smaller in overall size and more strongly ornamented compared to H.? heterodontus. However, high-crowned teeth of living H. say have a more concave labial face and more strongly lingually curved crown compared to H.? heterodontus, and the ornamentation on low-crowned teeth of the former species does not extend onto the transverse crest as it does on teeth of the latter species (see Reinecke et al. 2023: pls 64–67).
Original diagnosis after Cicimurri, Ebersole, Stringer, Starnes & Phillips (2025) p. 54-55 [34348]: Low-crowned teeth and high-crowned teeth are represented for this taxon. Low-crowned teeth generally have a convex labial face (amount of convexity varies) with a transversely depressed area near the apex. The labial face bears highly irregular ridges that are weakly to strongly developed and extend onto a wide transverse crest. The lingual face is smooth and bears a medial longitudinal crest flanked by lateral depressed areas. The bilobate root is low, located closer to, and extending beyond, the lingual crown margin. High-crowned teeth are cuspidate, with cusp height and degree of distal and lingual inclination varying. A thin transverse crest subdivides the crown into a large lingual face and much smaller labial face. The labial face may be virtually smooth but is usually ornamented with irregular and disconnected vertical ridges, sometimes forming a reticulated network. The lingual face is smooth and exhibits a medial longitudinal crest of varying width. New fossil species of Hypanus have yet to be named, but fossil teeth of several extant species (formerly placed in Dasyatis) have been reported. A small male tooth identified as H. americanus (Hildebrand & Schroeder, 1928) from the lower Miocene Pungo River Formation of North Carolina has a much more concave labial face and the lingual crown curvature is more pronounced apically than on Hypanus? heterodontus sp. nov. teeth of similar stature (Purdy et al. 2001). However, this comparison may be irrelevant, as we believe the Miocene tooth is that of a mobulid ray. Fitch (1966, 1970) reported a total of 12 H. dipterurus (Jordan & Gilbert, 1880) teeth from Pleistocene deposits of California, but he did not describe or illustrate them. Deynat & Brito (1994) reported caudal spines of H. guttatus (Bloch & Schneider, 1801) from the Miocene of central South America, but no teeth were noted. Pliocene teeth from the Yorktown Formation of North Carolina identified as H. say (Lesueur, 1817) by Purdy et al. (2001) are smaller in overall size and more strongly ornamented compared to H.? heterodontus. However, high-crowned teeth of living H. say have a more concave labial face and more strongly lingually curved crown compared to H.? heterodontus, and the ornamentation on low-crowned teeth of the former species does not extend onto the transverse crest as it does on teeth of the latter species (see Reinecke et al. 2023: pls 64–67).
Remarks
shark-references Species-ID=17562
shark-references Species-ID=17562
Image gallery
References
Late Oligocene fishes (Chondrichthyes and Osteichthyes) from the Catahoula Formation in Wayne County, Mississippi, USA. European Journal of Taxonomy, 984(1), 1–131
DOI: 10.5852/ejt.2025.984.2851
Late Oligocene fishes (Chondrichthyes and Osteichthyes) from the Catahoula Formation in Wayne County, Mississippi, USA. European Journal of Taxonomy, 984(1), 1–131
DOI: 10.5852/ejt.2025.984.2851
