Glyphis pagoda ( Noetling 1901 )

Shimada, Kenshu, Egi, Naoko, Tsubamoto, Takehisa, Nishioka, Yuichiro, Sonoda, Teppei & Takai, Masanaru, 2016, The extinct river shark Glyphis pagoda from the Miocene of Myanmar and a review of the fossil record of the genus Glyphis (Carcharhiniformes: Carcharhinidae), Zootaxa 4161 (2), pp. 237-251 : 240-245

Glyphis pagoda ( Noetling 1901)

( Figs. 2 , 3 B, 3C)

Carcharias (Prionodon) sp. Noetling 1895: 45.

Oxyrhina pagoda Noetling 1901: 372 , pl. XXV, figs. 1, 1a–1e, 2, 2a–2e, 3, 3a–3b.

Oxyrhina spallanzanii Bonaparte. Noetling 1901: 372 –373, pl. XXV, figs. 4, 5, 5a–e, 6, 6a–e.

Carcharias (Prionodon) gangeticus Müller & Henle. Noetling 1901: 375 , pl. XXV, figs. 11a–e, 12a, 12b, 13a, 13b, 14a, 14b, 15a, 15b.

Oxyrhina spallanzanii Bonaparte. Stuart 1910: 294 , pl. 25, figs. 9, 9a, 10, 10a, pl. 26, figs. 1, 2, 12, 12a.

Carcharias (Prionodon) collata Cope. Stuart 1910: 296 , pl. 26, figs. 12, 12a.

Carchariolamna heroni Hora 1939: 203 , text-fig. 1b, pl. 13, figs. 1–4.

Oxyrhina Agassiz. Hora 1939: 206 , text-fig. 2, pl. 13, figs. 5, 6.

Prionodon Müller & Henle. Hora 1939: 206 , 207, text-fig. 3 (left figure only; right figure may be tooth of Carcharhinus sp.), pl. 13, 7–10.

Aprionodon Gill. Hora 1939: 209 –210, text-fig. 6, pl. 13, figs. 16–20.

Prionodon pagoda (Noetling) . Leriche 1954: 7.

Prionodon sp. (Noetling). Leriche 1954: 7.

Oxyrhina pagoda Noetling. Sarma 1957: 104 , fig. 8.

Carcharodon megalodon Agassiz. Sarma 1957: 104 , fig. 10.

Carcharias (Prionodon) gangeticus Müller & Henle. Sarma 1957: 104 , fig. 11.

Oxyrhina spallanzanii Bonaparte. Sarma 1957 : fig. 12.

Carchariolamna heroni Hora. Tewari 1959: 2 –4, pl. X, fig. 1–3, text-fig. 2. 3.

Carcharhinus pagoda (Noetling) . Mohanti 1966: A76.

Carcharinus jhingrani Mehrotra, Misra & Srivastava 1973: 181 , pl. 1, fig. 1.

Carcharinus (Prionodon) gangeticus (Müller & Henle) . Mehrotra, Misra & Srivastava 1973: 183, pl. 1, fig. 2.

Isurus spallanzanii (Bonaparte) . Mehrotra, Misra & Srivastava 1973: 187 –188, pl. 1, fig. 10a, b.

Isurus pagoda (Noetling) . Mehrotra, Misra & Srivastava 1973: 188, pl. 1, fig. 11.

Isurus rameshi Mehrotra, Misra & Srivastava 1973: 188 , pl. 1, fig. 12.

Carcharodon tandoni Mehrotra, Misra & Srivastava 1973: 189 , pl. 2, fig. 4a, b.

Carcharodon carcharias Linnaeus. Mehrotra, Misra & Srivastava 1973: 191 , pl. 2, fig. 2 (caption " Carcharodon barcharias " [sic]), 6a, b.

Oxyrhina pagoda Noetling. Bhalla & Dev 1975: 98 .

Isurus spallanzanii (Bonaparte) . Sahni & Mehrotra 1981: 99, pl. 1, fig. 1.

Isurus pagoda (Noetling) . Sahni & Mehrotra 1981: 99, pl. 1, fig. 7.

Isurus rameshi Mehrotra, Misra & Srivastava. Sahni & Mehrotra 1981: 99 , pl. 1, fig. 2.

Carcharodon carcharias Linnaeus. Sahni & Mehrotra 1981: 99 , pl. 1, figs. 3–6.

Carcharodon tandoni Mehrotra, Misra & Srivastava. Sahni & Mehrotra 1981: 99 , pl. 1, fig. 9.

Carcharinus jhingrani Mehrotra, Misra & Srivastava. Sahni & Mehrotra 1981: 100 , pl. 2, fig. 3.

Isurus pagoda (Noetling) . Bhalla & Dev 1984b: 2, pl. I, fig. 9, 10.

Isurus spallanzanii (Bonaparte) . Bhalla & Dev 1984b: 2, pl. I, fig. 2.

Carcharhinus collatus Eastman. Bhalla & Dev 1984b: 4 , pl. I, fig. 5.

Isurus pagoda (Noetling) . Bhalla & Dev 1988: table 1.

Carcharodon carcharias Linnaeus. Mondal, Das, Mallick & Adhikary 2009: 141 , pl. II, figs. 1, 2.

Isurus desori Sismonda. Mondal, Das, Mallick & Adhikary 2009: 142 (in part), pl. II, figs. 11, 12.

Isurus oxyrinchus Rafinesque. Mondal, Das, Mallick & Adhikary 2009: 144 (in part), pl. II, figs. 14, 15.

Isurus pagoda (Noetling) . Mondal, Das, Mallick & Adhikary 2009: 144, pl. III, figs. 1–3.

Carcharodon carcharias Linnaeus. Ralte, Tiwari, Malsawma & Malsawma 2011: 332 , pl. 1, figs. 3a, 3b, 4a, 4b, 5a, 5b.

Isurus spallanzanii (Bonaparte) . Ralte, Tiwari, Malsawma & Malsawma 2011: 333, pl. 1, figs. 11a, 11b, 12a, 12b, 14a, 14b (not 13a–13c that is? Hemipristis serra ).

Isurus pagoda (Noetling) . Ralte, Tiwari, Malsawma & Malsawma 2011: 335, pl. 1, figs. 10a, 10b.

Glyphis pagoda (Noetling) . Cappetta 2012, p. 305.

Glyphis pagoda (Noetling) . Chavasseau, Aung Aung Khyaw, Chaimanee, Coster, Emonet, Aung Naing Soe, Rugbumrung, Soe Thura Tun & Jaeger 2013: table 19.5.

Carcharodon carcharias Linnaeus. Tiwari & Jauhri 2014 : pl. III, fig. c.

Isurus oxyrinchus Rafinesque. Sharma & Patnaik 2014: 293 , pl. 1, fig. 1a–c.

Isurus pagoda (Noetling) . Sharma & Patnaik 2014: 293, pl. 1, fig. 2a–c.

Isurus desori Sismonda. Sharma & Patnaik 2014: 293 , 294, pl. 1, fig. 3a, b.

Carcharodon carcharias Linnaeus. Sharma & Patnaik 2014: 294 , pl. 1, fig. 4a, b.

Emended diagnosis. Carcharhiniform teeth with orthodentine tooth histology and exhibiting strong dignathic heterodonty along with following combination of characters: upper teeth—broad triangular crown that approaches equilateral triangle; labial crown face flat and lingual face weakly convex; both labial and lingual faces smooth without any ornamentation; mesial margin of crown gently curved inward or nearly straight; occlusal half of distal margin gently convex or straight; basal half of distal margin gently to strongly concave; both mesial and distal margins finely serrated but coarser towards base; lingual crown base gently convex apically and labial crown base nearly straight; tooth neck practically absent on labial face and very narrow on lingual face; root rectangular and is as wide as crown base; root weakly bilobed with slight basal concavity and relatively sharp mesiobasal and distobasal corners; labiolingual thickness of root as thick as crown; lingual protuberance practically absent but generally with nutritive pore at center of lingual root face that continues basally as well-marked nutritive groove; both mesial and distal borders of nutritive groove generally slightly extending basally; lower teeth—narrow, sharply-pointed crown with sigmoidal profile and tooth root that may be narrow or broad; labial crown face gently convex and lingual face strongly convex; both labial and lingual faces smooth without ornamentation; apex of crown in teeth with narrow root may be distinctly broad to form spearhead shape; mesial and distal cutting edges weak in teeth with spearhead-shaped apex; fine serrations on portions with strong mesial and distal cutting edges; mesial and distal crown base may be substantially spread mesiodistally and may exhibit a pair of low, blunt lateral cusplets at terminal ends; lingual crown base weakly convex apically and labial crown base nearly straight; tooth neck practically absent on labial face and very narrow on lingual face; root weakly to strongly bilobed with low to high basal concavity, respectively; tip of each root lobe rounded; labiolingual thickness of root as thick as crown; lingual protuberance practically absent but with nutritive groove that continues basally at center of lingual root face.

Type material. Noetling (1901) did not specify any type materials, but his three illustrated teeth of ' Oxyrhina pagoda ' are here considered the type series for the species: GSI 0 7773 ( Noetling, 1901, pl. 25, fig. 1, 1a-e), GSI 0 7774 ( Noetling, 1901, pl. 25, fig. 2, 2a–e), and GSI 0 7775 ( Noetling, 1901, pl. 25, fig. 3, 3a–b). It should be noted that his three illustrated teeth of ' Oxyrhina spallanzanii ', which would constitute the type material for the species, are here considered conspecific with Glyphis pagoda : GSI 0 7776 ( Noetling, 1901, pl. 25, fig. 4), GSI 0 7777 ( Noetling, 1901, pl. 25, fig. 5, 5a–e), and GSI 0 7778 ( Noetling, 1901, pl. 25, fig. 6, 6a [top], 6a [bottom; likely sic], 6b–d). Likewise, his five illustrated teeth of ' Carcharias (Prionodon) gangeticus ', which would constitute the type material for the species, are here considered conspecific with Glyphis pagoda : GSI 0 7783 ( Noetling, 1901, pl. 25, fig. 11, 11a–e), GSI 0 7784 ( Noetling, 1901, pl. 25, fig. 12, 12a–b), GSI 0 7785, ( Noetling, 1901, pl. 25, fig. 13, 13a– b), GSI 0 7786 ( Noetling, 1901, pl. 25, fig. 14, 14a–b), and GSI 0 7787 ( Noetling, 1901, pl. 25, fig. 15, 15a–b).

New material. NMMP-KU-IR 1496 ( Fig. 2 C), nearly complete upper tooth from TeB-PG1 locality; NMMP- KU-IR 1522(1) ( Fig. 2 D), nearly complete lower tooth from YS2 locality; NMMP-KU-IR 1522(2) ( Fig. 2 E), nearly complete upper tooth YS2 locality; NMMP-KU-IR 1530(1) ( Fig. 2 F), nearly complete lower tooth from OND locality; NMMP-KU-IR 1530(2) ( Fig. 2 H), nearly complete lower tooth from OND locality; NMMP-KU-IR 1530(3) ( Fig. 2 I), nearly complete lower tooth from OND locality; NMMP-KU-IR 1530(4) ( Fig. 2 J), broken crown of lower tooth from OND locality; NMMP-KU-IR 1530(5) ( Fig. 2 G), crown of lower tooth (broken longitudinally exposing cross-sectional surfaces) from OND locality; NMMP-KU-IR 1530(6) ( Fig. 2 A, B), complete lower tooth in matrix from OND locality; NMMP-KU-IR 1530(7) ( Fig. 2 K), partial upper tooth from OND locality; NMMP- KU-IR 1530(8) ( Fig. 2 M), nearly complete upper tooth from OND locality; NMMP-KU-IR 1 530(9) ( Fig. 2 L), distal(?) half of upper tooth from OND locality; NMMP-KU-IR 1530(10) ( Fig. 2 O), crown of upper tooth from OND locality; NMMP-KU-IR 1530(11) ( Fig. 2 N), incomplete crown of upper tooth from OND locality; NMMP- KU-IR 1530(12) ( Fig. 2 P), nearly complete lower tooth from OND locality; NMMP-KU-IR 1530(13) ( Fig. 2 Q), nearly complete lower(?) tooth from OND locality; NMMP-KU-IR 1530(14) ( Fig. 2 R), crown of lower tooth from OND locality; NMMP-KU-IR 1 530(15) ( Fig. 2 S), complete lower tooth from OND locality; NMMP-KU-IR 1530(16) ( Fig. 2 T), nearly complete lower tooth from OND locality; NMMP-KU-IR 1530(17) ( Fig. 2 U), crown of lower tooth from OND locality.

Description. Twenty isolated teeth ( Fig. 2 ), one of which still encased in matrix exposing only its labial side ( Fig. 2 A, B); most teeth partially damaged or, where complete, generally show slight to moderate taphonomicallyinduced abrasion indicated by worn tooth surfaces ( Fig. 2 C, D); tooth size ranges from 10.0 mm to 18.5 mm in total tooth height (Appendix 1); orthodentine tooth histology with pulp cavity observable in specimens with damaged crown ( Fig. 2 G). Seven teeth identified as upper teeth characterized by broad, distally inclined triangular crown where crown width may slightly exceed crown height (Appendix 1). Crown inclinations suggesting as many as four of them are from the right side and three from the left side; remaining 13 specimens identified as lower teeth possess acutely-pointing, nearly erect cusp that may or may not have broad base. Six teeth are probably from the right side and seven possibly from left side.

Upper teeth―Crown ranging from about 8.0 mm to 12.4 mm in height (n = 6), from 9.8 mm to 11.9 mm in width (n = 2), and from 1.5 mm to 3.3 mm in thickness (n = 7) (Appendix 1; note that small sample size for crown widths is due to damaged crown base in most specimens); crown mesiodistally broad at base without prominent shoulders and overall narrows gradually apically; mesiodistal extensions of crown base short; lateral cusplets absent; fine, regularly-distributed serrations along mesial and distal cutting edges in which slight coarsening of serrations occur at basal one-third of crown; labial crown face smooth and slightly convex whereas lingual crown face smooth and flat; labial crown foot nearly straight whereas lingual crown foot gently curved; basal ledge or groove, and ornamentation (e.g., striations) absent on both sides of crown foot; tooth neck practically absent on both sides; crowns generally asymmetrical with varying degrees of distal inclination; root bilobed and as wide as crown, measuring from 11.5 mm to 11.9 mm (n = 2; Appendix 1, where root width equivalent to tooth width); root only slightly thicker than crown thickness, ranging from 2.4 mm to 3.9 mm (n = 5); labial root surface flat; lingual root surface gently convex without prominent lingual protuberance; prominent nutritive groove present; basal concavity very weak and may be interrupted by basally extending ridges of root that define nutritive groove (e.g., Fig. 2 E).

Lower teeth―Crown narrower than that in upper teeth, ranging from about 8.0 mm to 13.5 mm in height (n = 11), from 3.6 mm to 8.6 mm in width (n = 10), and from 1.7 mm to 3.3 mm in thickness (n = 10) (Appendix 1); crown base may be mesiodistally narrow (e.g., Fig. 2 B, D, F), moderately wide (e.g., Fig. 2 P, Q), or broad to form narrow shoulders extending outward (e.g., Fig. 2 T) and may even bear a pair of short, blunt lateral cusplets (e.g., Fig. 2 S); lingually curved crown developing apically into sharp, narrow cusp with a slight labial flex; spearheadlike slight mesiodistal expansion with well-developed cutting edges present at apex of tall narrow crown in which the rest of the those teeth tend to have weakly developed cutting edge (e.g., Fig. 2 B, F–J); fine, regularlydistributed serrations present along mesial and distal cutting edges in teeth with moderately wide crown base; labial crown face strongly convex; labial crown foot nearly straight whereas lingual crown foot gently curved; basal ledge or groove, and ornamentation (e.g., striations) absent on both sides of crown foot; lingual crown face flat and smooth, lacking ornamentation; tooth neck practically absent on both sides; crowns almost symmetrical or with slight inclination; root bilobed and slightly wider than crown base, measuring from 5.7 mm to 10.9 mm (n = 7; Appendix 1, where root width equivalent to total tooth width); root only slightly thicker than crown thickness, ranging from 1.9 mm to 5.5 mm (n = 9; Appendix 1 where root thickness equivalent to tooth thickness); labial root surface slightly rounded; lingual root surface convex without prominent lingual protuberance; prominent nutritive groove present; basal concavity weak ( Fig. 2 D, F, P, S, T) to moderate ( Fig. 2 B, H, I, Q) and may be interrupted by basally extending ridges of root that define nutritive groove ( Fig. 2 F, Q, S).

Taxonomic remarks. Until recently, when the genus Glyphis was resurrected to be a valid taxon within Carcharhiniformes ( Compagno 1984, 1988), the species G. pagoda had been placed under at least the following eight other genera: Aprionodon , Carcharias , Carcharinus , Carchariolamna , Carcharodon , Isurus , Oxyrhina , and Prionodon (see synonymy list above). We note that G. pagoda (with an orthodentine tooth histology) does not belong to Lamniformes (i.e., Carcharias , Carchariolamna , Carcharodon , Isurus , and Oxyrhina ) which has osteodentine tooth histology (e.g., Welton & Farish 1993). We note that a spearhead-shaped crown apex as defined by Noetling (1901) is a diagnostic characteristic for G. pagoda , and there is little doubt that previous reports of the species are genuinely reliable due to this unique crown morphology among Cenozoic elasmobranchs (see Cappetta 2012).

Hora (1939) referred five teeth to Aprionodon sp. from the Miocene of Orissa, India, at least one of which (text-fig. 6) exhibits a narrow crown with a spearhead-shaped apex and is interpreted to be a lower tooth of G. pagoda . Narrow teeth of G. pagoda without a spearhead-shaped apex, here interpreted to be distally located lower teeth, have also been referred to other taxa, such as Carcharias (Prionodon) collata , Carcharhinus collatus , Carchariolamna heroni , Oxyrhina spallanzanii , Oxyrhina sp., Isurus spallanzanii , I. rameshi , I. desori , and I. oxyrinchus (see synonymy list for references). Likewise, broad triangular upper teeth of G. pagoda were previously referred to different taxa, including Carcharias (Prionodon) sp., Carcharias (Prionodon) gangeticus , Carcharinus (Prionodon) gangeticus , Carcharinus jhingrani , Carcharodon carcharias , Carcharodon megalodon , and Carcharodon tandoni (see synonymy list for references).

Noetling (1901) described Glyphis pagoda on the basis of teeth collected from an uncertain Miocene horizon near Thayetmyo, Myanmar. Misidentifications of G. pagoda as other taxa stem from the original diagnosis of the species, which was solely based on the presence of the spearhead-shaped crown apex. Case in point, among some other shark taxa Noetling (1901) reported were teeth of ' O. spallanzanii ' from the same stratigraphic range where specimens of ' O. pagoda ' and ' Carcharias (Prionodon) gangeticus ' occurred. The teeth of O. spallanzanii are similar to O. pagoda , but Noetling (1901, p. 373) noted that the "species is easily distinguished from Oxyrhina pagoda ... by the absence of the arrow-head like expansion of the upper end [= crown apex]." In fact, Noetling's (1901) specimens of O. spallanzanii are within the morphological range of lower teeth in extant Glyphis spp. that may not necessarily exhibit the 'arrow-head like expansion' of the crown apex. Furthermore, Noetling's (1901) description and illustrations of teeth of C. (P.) gangeticus are morphologically consistent with upper teeth of extant Glyphis spp. (e.g., see Müller & Henle 1839, pl. 13; Compagno 1984, p. 509; Cappetta 2012, fig. 287, 288). The fact that localities where G. pagoda is reported generally also yield C. (P.) gangeticus and O. spallanzanii (including those species under different generic assignments) does not contradict our interpretation that all these nominal taxa are conspecific. The original narrow definition of the species by Noetling (1901) clearly led to the perpetuation of misidentification of G. pagoda to other taxa from Miocene deposits in the region (including India) as demonstrated in the synonymy list above. It is particularly ironic that Noetling (1895, p. 45) noted, in describing his ' Carcharias (Prionodon) sp. ' from the Miocene of Myanmar prior to his description of ' O. pagoda ' in 1901, now interpreted to be G. pagoda , that "I refrain from identifying them specifically [to a new species] … considering the great variety in the shape of the teeth according to position, even within the individual."

Figure 3 illustrates the upper and lower dental series of extant G. g l y p h i s as an example to show the diagnathic heterodonty present in the shark as well as to show tentative correspondences in tooth positions of selected teeth of G. pagoda collected in the Miocene of Myanmar ( Fig. 2 ). It also lists, for each morphological range, names of previously misidentified taxa for G. pagoda (see synonymy list above). Nevertheless, the wide morphological range observed in our fossil samples from Myanmar may invoke the question of the possibility that our specimens may represent multiple species, rather than our interpretation that they are all conspecific. We contend that they are conspecific because the range of morphological variation seen in the teeth is within the range of intraindividual variation in extant Glyphis ( Compagno 1984, p. 509), but more significantly because the 20 described fossil teeth are the only shark remains found and collected at those Miocene localities and at least 19 of them occurred in freshwater-deposits (Irrawaddy sediments: see Bender 1983). Among extant sharks, those with low-salinity tolerance are rare. The only extant sharks that regularly inhabit or venture into freshwater environments are Glyphis spp. and the bull shark Carcharhinus leucas (Valenciennes) ( Compagno 1984, 1988). Cases of their cooccurrence in the same river systems are known ( Compagno 1988; Berra 2010), but C. leucas , which has more robust teeth and coarser serrations than Glyphis spp. ( Compagno 1984, 1988), is not recognized in the G. pagoda - bearing Miocene deposits. Therefore, it is more parsimonious to consider that only one freshwater-tolerant shark species, G. pagoda , is present. It is also worth noting that the wide range of tooth morphologies (upper vs. lower as well as mesial vs. distal) represented in our sample is what one might expect to find from random surface sampling.

Figures

FIGURE 2. Teeth of Glyphis pagoda from the upper Middle to lower Upper Miocene of Myanmar. A, NMMP-KU-IR 1530 (6), lower tooth in matrix. B, NMMP-KU-IR 1530 (6), lower tooth in close-up view (cf. Fig. 2 A). C, NMMP-KU-IR 1496, upper tooth. D, NMMP-KU-IR 1522 (1), lower tooth. E, NMMP-KU-IR 1522 (2), upper tooth. F, NMMP-KU-IR 1530 (1), lower tooth. G, NMMP-KU-IR 1530 (5), lower tooth. H, NMMP-KU-IR 1530 (2), lower tooth. I, NMMP-KU-IR 1530 (3), lower tooth. J, NMMP-KU-IR 1530 (4), lower tooth. K, NMMP-KU-IR 1530 (7), upper tooth. L, NMMP-KU-IR 1530 (9), upper tooth. M, NMMP-KU-IR 1530 (8), upper tooth. N, NMMP-KU-IR 1530 (11), upper tooth. O, NMMP-KU-IR 1530 (10), upper tooth. P, NMMP-KU-IR 1530 (12), lower tooth. Q, NMMP-KU-IR 1530 (13), lower tooth. R, NMMP-KU-IR 1530 (14), lower tooth. S, NMMP-KU-IR 1530 (15), lower tooth. T, NMMP-KU-IR 1530 (16), lower tooth. U, NMMP-KU-IR 1530 (17), lower tooth. Orientations: A, B = labial view; C – G = lingual (left), mesial (middle), and labial (right) views (note: mesial view in G = longitudinal cross-sectional view to show pulp cavity); H – U, lingual (left) and labial (right) views. All scales = 5 mm.

FIGURE 3. Dentition of extant Glyphis (A) compared with selected teeth of G. pagoda from the Miocene of Myanmar (B, C), and three separate morphological ranges in the dentition of Glyphis that alluded the total intraindividual variation of G. pagoda (1 ‒ 3). A, upper and lower dental series of extant G. glyphis in labial view (jaw symphysis to the left; after Compagno 1984, p. 509). B, isolated upper teeth of G. pagoda artificially aligned with size adjustment to show approximate correspondence with upper teeth of extant G. glyphis (top half of Fig. 3 A): from left to right, NMMP-KU-IR 1522 (2) (Fig. 2 E), NMMP-KU-IR 1496 (Fig. 2 C; image reversed), NMMP-KU-IR 1530 (8) (Fig. 2 M; image reversed), NMMP-KU-IR 1530 (7) (Fig. 2 K; image reversed), NMMP-KU-IR 1530 (10) (Fig. 2 O), NMMP-KU-IR 1530 (11) (Fig. 2 N). C, isolated lower teeth of G. pagoda artificially aligned with size adjustment to show approximate correspondence with lower teeth of extant G. glyphis (bottom half of Fig. 3 A): from left to right, NMMP-KU-IR 1530 (1) (Fig. 2 F; image reversed), NMMP-KU-IR 1530 (6) (Fig. 2 B; image reversed), NMMP-KU-IR 1530 (3) (Fig. 2 I; image reversed), NMMP-KU-IR 1530 (2) (Fig. 2 H; image reversed), NMMP-KU-IR 1530 (16) (Fig. 2 T), NMMP-KU-IR 1530 (15) (Fig. 2 S; image reversed), NMMP-KU-IR 1522 (1) (Fig. 2 D; image reversed), NMMP-KU-IR 1530 (12) (Fig. 2 P; image reversed). 1, original range of morphological variation defined by Noetling (1901); 2, morphological range of G. pagoda teeth previously misidentified as or misclassified by previous workers to Carcharias (Prionodon) sp., C. (P.) gangeticus, Carcharinus (P.) gangeticus, C. jhingrani, Carcharodon carcharias, C. megalodon, or C. tandoni (e. g., see synonymy list in text); 3, morphological range of G. pagoda teeth previously misidentified as or misclassified by previous workers to Carcharias (P.) collata, Carcharhinus collatus, Carchariolamna heroni, Oxyrhina spallanzanii, O. sp., Isurus spallanzanii, I. rameshi, I. desori, or I. oxyrinchus (e. g., see synonymy list in text). All scales = 5 mm.