Table 1.
Summary of all examined shark jaws.
Specimens are either deposited in the collection of the Department of Palaentology, University of Vienna (UV) or in the collection of the Earth and Planetary Sciences of Birkbeck, University of London (BBK) and are publicly accessible.
Table 2.
Summary of all examined extant and fossil shark teeth.
All specimens are deposited in the collection of the Department of Palaentology at the University of Vienna and are publicly accessible.
Fig 1.
Terminology used to describe the position of teeth within the jaw and tooth files.
(A) Jaw of Hemipristis elongata in anterior view, (B) anterior part of the lower jaw of Hemipristis elongata, (C) Tooth series LPC6 of Hemipristis elongata. F, functional tooth; LMC, left Meckel’s cartilage; LPC, left palatoquadrate cartilage; MC, Meckel’s cartilage (lower jaw); PQ, palatoquadrate cartilage (upper jaw); R, replacement tooth; RMC, right Meckel’s cartilage, RPC, right palatoquadrate cartilage.
Fig 2.
Micro-CT images of tooth series of sharks of the genus Carcharhinus.
Tooth files showing the number of teeth, tooth stages and mineralization in (A) LMC3 (lower jaw) C. melanopterus, (B) LPC3 (upper jaw) C. melanopterus (EMRG-Chond-J-3), (C) LMC3 C. obscurus, (D) LPC3 C. obscurus (EMRG-Chond-J-5), (E) RMC3 C. signatus, (F) RPC3 C. signatus (EMRG-Chond-J-4). Scalebar = 0.5cm. en, enameloid; mc, Meckel’s cartilage; or, orthodentine; pc, pulp cavity; pq, palatoquadrate.
Fig 3.
Micro-CT images of tooth series of the carcharhinid sharks Galeocerdo cuvier, Prionace glauca, and Rhizoprionodon acutus.
Tooth files showing the number of teeth, tooth stages and mineralization in (A) RMC3 (lower jaw) Galeocerdo cuvier, (B) RPC3 (upper jaw) Galeocerdo cuvier (EMRG-Chond-J-13), (C) LMC3 Prionace glauca, (D) LPC3 Prionace glauca (EMRG-Chond-J-6), (E) LMC3 Rhizoprionodon acutus, (F) LPC3 Rhizoprionodon acutus (EMRG-Chond-J-7). Scalebar = 0.5cm. en, enameloid; mc, Meckel’s cartilage; or, orthodentine; pc, pulp cavity; pq, palatoquadrate.
Fig 4.
Micro-CT images of tooth series of sharks of the family Hemigaleidae.
Tooth files showing the number of teeth, tooth stages and mineralization in (A) LMC3 (lower jaw) Chaenogaleus macrostoma, (B) LPC3 (upper jaw) Chaenogaleus macrostoma (CD042), (C) LMC3 Hemigaleus microstoma, (D) LPC3 Hemigaleus microstoma (CD045), (E) LMC3 Paragaleus randalli, (F) LPC3 Paragaleus randalli (CD046). Scalebar = 0.5cm. en, enameloid; mc, Meckel’s cartilage; or, orthodentine; pc, pulp cavity; pq, palatoquadrate.
Fig 5.
Micro-CT images of tooth series of the sphyrnid shark Sphyrna zygaena.
Tooth files showing the number of teeth, tooth stages and mineralization. (A) LMC3 (lower jaw), (B) LPC3 (upper jaw) of Sphyrna zygaena (EMRG-Chond-J-8). Scalebar = 0.5cm. en, enameloid; mc, Meckel’s cartilage; or, orthodentine; pc, pulp cavity; pq, palatoquadrate.
Fig 6.
Micro-CT images of tooth series of Hemipristis elongata.
Tooth files showing the number of teeth, tooth stages and mineralization in (A), (B) LMC3 (lower jaw), (C), (D) LPC6 (upper jaw) of Hemipristis elongata EMRG-Chond-J-1. Scalebar = 0.5cm. en, enameloid; mc, Meckel’s cartilage; or, orthodentine; os, osteodentine; pc, pulp cavity; pq, palatoquadrate.
Fig 7.
Micro-CT images of functional teeth of each tooth series in the lower and upper jaw of Hemipristis elongata.
The jaws show strong dignathic and monognathic heterodonty with slender anterior teeth for grasping, and serrated lateral teeth for cutting the prey. Although the morphology of teeth within a horizontal row change drastically, the tooth histology is the same for each functional tooth. Scalebar = 0.5cm.
Table 3.
Mineralization sequence in Hemipristis elongata.
Table showing the degree of mineralization for every tooth within the tooth files LMC3 and LMC4. Tooth files of the lower jaw show an alternate mineralization pattern, with replacement teeth of one file showing a higher degree of mineralization than teeth of the adjacent file. en, enameloid; or, orthodentine; os, osteodentine.
Fig 8.
Micro-CT images of tooth sections of different developmental stages in †Hemipristis serra in frontal, sagittal and axial view.
(A), (B), (C) EMRG-Chond-T-9, Pulp cavity hollow with little intrusion of osteodentine; (D), (E), (F) EMRG-Chond-T-12, Pulp cavity hollow, half filled with osteodentine; (G), (H), (I) EMRG-Chond-T-10, pulp cavity filled, tooth fully mineralized; scalebar = 1cm; en, enameloid; mc, Meckel’s cartilage; or, orthodentine; os, osteodentine; pc, pulp cavity; pq, palatoquadrate.
Fig 9.
Root mineralization in Hemipristis.
(A) Mineralization sequence of the root in Hemipristis elongata; (B) fully mineralized tooth with fully filled pulp cavity and dense osteodentine in the root in †Hemipristis serra (EMRG-Chond-T-11); (C) tooth with hollow pulp cavity in the crown and porous osteodentine within the root displaying a replacement tooth of †Hemipristis serra (EMRG-Chond-T-9). Scalebar = 1cm.
Fig 10.
Micro-CT images of tooth sections of †Hemipristis curvatus, Carcharhinus leucas, and Galeocerdo cuvier in frontal, sagittal, and axial view.
(A), (B), (C) †Hemipristis curvatus (EMRG-Chond-T-20), the pulp cavity is hollow with little intrusion of osteodentine from the root; (D), (E), (F) Carcharhinus leucas (EMRG-Chond-T-15), tooth with hollow pulp cavity and a shark border between the osteodentine of the root and the pulp cavity; (G), (H), (I) Galeocerdo cuvier (EMRG-Chond-T-16), tooth with hollow pulp cavity and a sharp border between the osteodentine of the root and the pulp cavity; scalebar = 1cm; en, enameloid; mc, Meckel’s cartilage; or, orthodentine; os, osteodentine; pc, pulp cavity; pq, palatoquadrate.
Fig 11.
Tooth sections of an orthodont (Carcharhinus leucas), pseudoosteodont (†Hemipristis serra) and osteodont shark (Isurus oxyrinchus).
The white line indicates the plane of the section. (A), (B), (C) Carcharhinus leucas (EMRG-Chond-T-15) has a hollow pulp cavity surrounded by tightly packed orthodentine; (D, E, F) fully mineralized tooth of †Hemipristis serra (EMRG-Chond-T-11) with a thick layer of orthodentine, surrounding the osteodentine core; (G, H, I) the crown of Isurus oxyrinchus (EMRG-Chond-T-14) is fully filled by osteodentine. Orthodentine is absent in this species. en, enameloid; mc, Meckel’s cartilage; or, orthodentine; os, osteodentine; pc, pulp cavity; pq, palatoquadrate.