Sphyrna gracile
Cicimurri, Ebersole, Stringer, Starnes & Phillips, 2025
Classification: Elasmobranchii Carcharhiniformes Sphyrnidae
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
Description:
Citation: Sphyrna gracile 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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Sphyrna gracile Cicimurri, Ebersole, Stringer, Starnes & Phillips, 2025; “Sphyrna” gracile sp. nov., teeth. A–C. SC2013.28.155 (paratype), lower left anterior tooth. A. Labial view. B. Lingual view. C. Mesial view. D–E. SC2013.28.913, lower right lateral tooth. D. Labial view. E. Lingual view. F–G. SC2013.28.912, lower left lateral tooth. F. Labial view. G. Lingual view. H–I. SC2013.28.914, lower left lateral tooth. H. Labial view. I. Lingual view. J–K. SC2013.28.156, upper left lateral tooth. J. Labial view. K. Lingual view. L–N. SC2013.28.162 (paratype), lower left lateral tooth. L. Labial view. M. Lingual view. N. Mesial view. O–Q. SC2013.28.158 (holotype), upper right lateral tooth. O. Labial view. P. Lingual view. Q. Mesial view. R–S. SC2013.28.157, upper left anterior tooth. R. Labial view. S. Lingual view. T–U. SC2013.28.161, upper right lateral tooth. T. Labial view. U. Lingual view. Scale bars = 3 mm. From Cicimurri et al. (2025)
Sphyrna gracile Cicimurri, Ebersole, Stringer, Starnes & Phillips, 2025; “Sphyrna” gracile sp. nov., teeth. A–C. SC2013.28.155 (paratype), lower left anterior tooth. A. Labial view. B. Lingual view. C. Mesial view. D–E. SC2013.28.913, lower right lateral tooth. D. Labial view. E. Lingual view. F–G. SC2013.28.912, lower left lateral tooth. F. Labial view. G. Lingual view. H–I. SC2013.28.914, lower left lateral tooth. H. Labial view. I. Lingual view. J–K. SC2013.28.156, upper left lateral tooth. J. Labial view. K. Lingual view. L–N. SC2013.28.162 (paratype), lower left lateral tooth. L. Labial view. M. Lingual view. N. Mesial view. O–Q. SC2013.28.158 (holotype), upper right lateral tooth. O. Labial view. P. Lingual view. Q. Mesial view. R–S. SC2013.28.157, upper left anterior tooth. R. Labial view. S. Lingual view. T–U. SC2013.28.161, upper right lateral tooth. T. Labial view. U. Lingual view. Scale bars = 3 mm. From Cicimurri et al. (2025)
Description
Original diagnosis after Cicimurri, Ebersole, Stringer, Starnes & Phillips (2025) p. 36 [34348]: Mesio-distally wide teeth consisting of a large main cusp and a distal heel. The main cusp is broadly triangular and distally inclined to varying degrees. The mesial cutting edge is straight to weakly convex on the main cusp, but it extends to the end of the mesial root lobe generally through a sloping transition at the base of the cusp. The distal cutting edge is shorter and straight to weakly convex. The distal heel is elongated, low, straight to weakly convex, and differentiated from the distal cutting edge by a shallow notch. All cutting edges are smooth. The root is bilobate with short, sub-rectangular lobes that are highly diverging. The basal margin is straight to weakly concave. The lingual root face is thick, and there is a distinctive medially located nutritive groove. These teeth differ from fossil species reported in the literature, like those of the Miocene Sphyrna arambourgi Cappetta, 1970, by having a wider main cusp and weakly sinuous (as opposed to straight) mesial cutting edge. Additionally, “S.” gracile sp. nov. teeth can be separated from those of both S. arambourgi and S. integra (Probst, 1878) by having an elongated and straight to weakly convex distal heel (as opposed to being rather short and occasionally cuspidate in the latter taxa). Furthermore, the lower teeth of the former taxon have an angular mesial cutting edge, whereas this edge is curved in the latter taxa. “Sphyrna” gracile teeth differ from those of the Miocene S. laevissima (Cope, 1867) by being less robust and by being smaller in mesio-distal width (up to 6 mm for “S.” gracile vs 1 cm for S. laevissima).
Original diagnosis after Cicimurri, Ebersole, Stringer, Starnes & Phillips (2025) p. 36 [34348]: Mesio-distally wide teeth consisting of a large main cusp and a distal heel. The main cusp is broadly triangular and distally inclined to varying degrees. The mesial cutting edge is straight to weakly convex on the main cusp, but it extends to the end of the mesial root lobe generally through a sloping transition at the base of the cusp. The distal cutting edge is shorter and straight to weakly convex. The distal heel is elongated, low, straight to weakly convex, and differentiated from the distal cutting edge by a shallow notch. All cutting edges are smooth. The root is bilobate with short, sub-rectangular lobes that are highly diverging. The basal margin is straight to weakly concave. The lingual root face is thick, and there is a distinctive medially located nutritive groove. These teeth differ from fossil species reported in the literature, like those of the Miocene Sphyrna arambourgi Cappetta, 1970, by having a wider main cusp and weakly sinuous (as opposed to straight) mesial cutting edge. Additionally, “S.” gracile sp. nov. teeth can be separated from those of both S. arambourgi and S. integra (Probst, 1878) by having an elongated and straight to weakly convex distal heel (as opposed to being rather short and occasionally cuspidate in the latter taxa). Furthermore, the lower teeth of the former taxon have an angular mesial cutting edge, whereas this edge is curved in the latter taxa. “Sphyrna” gracile teeth differ from those of the Miocene S. laevissima (Cope, 1867) by being less robust and by being smaller in mesio-distal width (up to 6 mm for “S.” gracile vs 1 cm for S. laevissima).
Remarks
shark-references Species-ID=17563
shark-references Species-ID=17563
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
