Bharattherium
Bharattherium | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Family: | †Sudamericidae |
Genus: | †Bharattherium Prasad et al., 2007 |
Species: | †B. bonapartei
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Binomial name | |
†Bharattherium bonapartei Prasad et al., 2007
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Synonyms[2] | |
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Bharattherium is a
Bharattherium molariforms are high, curved teeth, with a height of 6 to 8.5 millimetres (0.24 to 0.33 in). In a number of teeth tentatively identified as fourth lower molariforms (mf4), there is a large furrow on one side and a deep cavity (infundibulum) in the middle of the tooth. Another tooth, perhaps a third lower molariform, has two furrows on one side and three infundibula on the other. The tooth enamel has traits that have been interpreted as protecting against cracks in the teeth. The hypsodont (high-crowned) teeth of sudamericids like Bharattherium are reminiscent of later grazing mammals, and the discovery of grass in Indian fossil sites contemporaneous with those yielding Bharattherium suggest that sudamericids were indeed grazers.
Taxonomy
A
In 2007, two teams of scientists independently named the Indian gondwanathere on the basis of new material; both teams included VPL/JU/NKIM/25 in their newly named species. Guntupalli Prasad and colleagues named the animal Bharattherium bonapartei on the basis of an additional tooth, VPL/JU/IM/33,
Description
Fossil | Locality | Tooth position | References |
---|---|---|---|
GSI/SR/PAL-G059 | Gokak | Left mf3 | [9] |
GSI/SR/PAL-G070 | Gokak | Right mf4 | [10] |
GSI/SR/PAL-G074 | Gokak | Right mf4 | [11] |
VPL/JU/IM/33 | Kisalpuri | Molariform | [12] |
GSI/SR/PAL-N071 | Naskal | Left mf4 | [13] |
GSI/SR/PAL-N210 | Naskal | Left i1 | [9] |
GSI/SR/PAL-N212 | Naskal | Right mf4 | [9] |
VPL/JU/NKIM/25 | Naskal | Left mf4 | [14] |
Bharattherium bonapartei is known from a total of eight isolated teeth.
Molariforms
GSI/SR/PAL-G074, a well-preserved right mf4 that Wilson and colleagues selected as the
The right mf4 GSI/SR/PAL-G070, which is damaged on the buccal, distal, and lingual sides, is 8.40 mm high, but has an occlusal surface of only 2.49 × 1.75 mm. Unlike in GSI/SR/PAL-G074, the dentine on the occlusal surface is not exposed, and the occlusal surface is oval in shape. Furthermore, the V-shaped islet is larger and the lingual furrow is less prominent at the occlusal surface, because it tapers near the tip of the tooth. In the heavily damaged left mf4 GSI/SR/PAL-N071 (height 7.16 mm), only the distal side is well preserved. The infundibulum is exposed internally; it extends 4.01 mm down the crown.[21] The occlusal surface is poorly preserved, but its dimensions are at least 2.14 × 2.42 mm. GSI/SR/PAL-N212, a right mf4, is damaged on the mesial side and has a height of 5.86 mm and an occlusal surface of at least 2.66 x 2.04 mm. Cementum fills the V-shaped islet.[22]
VPL/JU/NKIM/25 was the first Indian gondwanathere fossil to be described; it is damaged on one side. Wilson and colleagues identified it as a left mf4 (implying that the damaged side is buccal) with strong similarities to GSI/SR/PAL-G070, including a curved crown and a V-shaped enamel islet atop a deep infundibulum. The occlusal surface is oval. The tooth is 6 mm high and Wilson and colleagues estimate that the occlusal surface is 2.5 × 1.8 mm, close to the dimensions of GSI/SR/PAL-G070. They suggest the tooth probably had enamel on all sides of the crown,[22] but Prasad and colleagues point to a possible enamel-dentine junction on the damaged side as evidence that enamel may be absent there.[18]
GSI/SR/PAL-G059, identified as a left mf3, has a height of 5.97 mm at the mesial side, but only 2.02 mm at the distal side because of curvature. On the lingual side, two long furrows are visible, and on the buccal side breakage exposes three long infundibula, of which the most mesial one is the longest and the most distal one the shortest. In the occlusal surface, these three infundibula merge into a single islet. In addition, three dentine lakes are visible in the occlusal surface, which has dimensions of 4.58 × at least 2.52 mm. Although in Sudamerica, mf2, mf3, and the upper molariforms MF3 and MF4 all have three lophs, like GSI/SR/PAL-G059, its curvature matches the mf3 of Sudamerica best.[22]
VPL/JU/IM/33, the holotype of Bharattherium bonapartei, is 7.33 mm high,[5] 2.66 mm long, and 2.0 mm wide. The occlusal surface is about rectangular and is mostly covered by a V-shaped dentine lake, which encloses a small heart-shaped enamel islet at the top of an cementum-filled infundibulum. A vertical furrow is also present. Near the top of the tooth, enamel covers the entire crown, but further down there is no enamel on the concave face of the tooth.[18]
Incisor
The left i1 GSI/SR/PAL-N210 is flat on the medial side (towards the middle of the head) but convex on the lateral side (towards the side of the head) and bears a shallow groove on the lateral side. At the base, the tooth is broadest on the lower end. The tooth is slightly curved upward towards the tip. Measured on the lower side, the tooth is 11.76 mm long, but breakage means the true length is probably larger. The depth of the tooth is about 3.39 mm. Wilson and colleagues identified this incisor as Dakshina on the basis of its size;[22] the upper and lower incisor that they assigned to an indeterminate gondwanathere are smaller.[23]
Enamel microstructure
The microstructure of the enamel of VPL/JU/NKIM/25 has been studied. Unlike other gondwanatheres, it has enamel consisting of three layers—radial enamel, tangential enamel, and PLEX.[24] The rows of small, round enamel prisms are separated by interprismatic matrix[3] that forms crystals oriented at right angles relative to the prisms. Prisms arise at the enamel-dentine junction, run through the enamel, and meet the outer enamel at a high angle. These features of the enamel are apparently adaptations that protect the tooth from cracks.[25]
Relationships
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Relationships among gondwanatheres[26] |
Bharattherium is identifiable as a sudamericid because it has hypsodont molariforms with cementum-filled furrows.[27] Among the four known sudamericid genera—Gondwanatherium and Sudamerica from Argentina; Lavanify from Madagascar; and Bharattherium—it shares with Sudamerica and Lavanify the presence of furrows that extend down to the base of the tooth.[28] In addition, it shares several features with Lavanify, suggesting the two are closely related.[29] Wilson and colleagues list three features shared by the two: the presence of an infundibulum (seen in only one of two specimens of Lavanify), interprismatic matrix, and perikymata.[24] Prasad and colleagues also interpreted the interprismatic matrix as a shared character, but added the absence of enamel on one side of the tooth crown.[30] Wilson and colleagues identified the presence of a V-shaped enamel lake on mf4 and of three layers in the enamel as autapomorphies (uniquely derived characters) of the Indian sudamericid.[24]
Range and ecology
Remains of Bharattherium have been found at three widely separated Late Cretaceous sites in peninsular India—Naskal,
In modern mammals, hypsodont teeth are often associated with diets that include abrasive vegetation such as
It is among the two Indian mammal taxa that are inferred to have survived the
Notes
- ^ This tooth is stored in the collection of mammals from the Naskal fossil site in the Vertebrate Palaeontology Laboratory at the University of Jammu, numbered 25.[3]
- ^ This tooth is stored in the collection of mammals from the Intertrappean Beds in the collections of Jammu University's Vertebrate Palaeontology Laboratory, numbered 33.[5]
- ^ Like the others described by Wilson and colleagues, this tooth is stored in the collections of the Palaeontology Division of the Southern Region of the Geological Survey of India.[7]
References
- ^ a b Wilson, G. P.; Widdowson, M.; Anantharaman, S.; Das Sarma, D. C.; Wilson, J. A.; Renne, P. R. (October 27, 2016). "New mammalian fossils from the intertrappean beds of the southern part of the Deccan Volcanic Province and the Cretaceous-Paleogene transition in India". SVP 2016 Program Book. Vol. 6. Society of Vertebrate Paleontology. p. 252.
- ^ a b Prasad 2008, p. 91.
- ^ a b Krause et al. 1997, p. 505.
- ^ Krause et al. 1997, p. 504.
- ^ a b c Prasad et al. 2007, p. 19.
- ^ Wilson, Das Sarma & Anantharaman 2007, p. 521.
- ^ a b c d Wilson, Das Sarma & Anantharaman 2007, p. 522.
- ^ Wilson, Das Sarma & Anantharaman 2007, pp. 526–527.
- ^ a b c Wilson, Das Sarma & Anantharaman 2007, pp. 522, 525.
- ^ Wilson, Das Sarma & Anantharaman 2007, pp. 522, 524.
- ^ Wilson, Das Sarma & Anantharaman 2007, pp. 522–524.
- ^ Prasad et al. 2007, pp. 19–20.
- ^ Wilson, Das Sarma & Anantharaman 2007, pp. 522, 524–525.
- ^ Krause et al. 1997, pp. 505–506; von Koenigswald, Goin & Pascual 1999, pp. 290–293; Prasad et al. 2007, pp. 19–20; Wilson, Das Sarma & Anantharaman 2007, pp. 522, 525.
- ^ Prasad et al. 2007, p. 17; Wilson, Das Sarma & Anantharaman 2007, p. 522.
- ^ Wilson, Das Sarma & Anantharaman 2007, pp. 525–526.
- ^ Prasad et al. 2007, p. 22.
- ^ a b c Prasad et al. 2007, p. 20.
- ^ Wilson, Das Sarma & Anantharaman 2007, p. 526; Prasad et al. 2007, pp. 19, 21.
- ^ a b Wilson, Das Sarma & Anantharaman 2007, p. 523.
- ^ Wilson, Das Sarma & Anantharaman 2007, p. 524.
- ^ a b c d Wilson, Das Sarma & Anantharaman 2007, p. 525.
- ^ Wilson, Das Sarma & Anantharaman 2007, p. 527.
- ^ a b c Wilson, Das Sarma & Anantharaman 2007, p. 526.
- ^ Prasad et al. 2007, p. 24.
- ^ Krause et al. 1997, fig. 3; Wilson, Das Sarma & Anantharaman 2007, p. 526; Prasad et al. 2007, p. 23.
- ^ Wilson, Das Sarma & Anantharaman 2007, p. 526; Prasad et al. 2007, p. 20.
- ^ Wilson, Das Sarma & Anantharaman 2007, p. 526; Prasad et al. 2007, p. 21.
- ^ Wilson, Das Sarma & Anantharaman 2007, p. 526; Prasad et al. 2007, p. 23.
- ^ Prasad et al. 2007, p. 21.
- ^ Wilson, Das Sarma & Anantharaman 2007, pp. 521–522; Prasad et al. 2007, p. 19.
- ^ Wilson, Das Sarma & Anantharaman 2007, p. 522; Prasad et al. 2007, p. 19.
- ^ Prasad & Sahni 2009, pp. 370, 373.
- ^ Wilson, Das Sarma & Anantharaman 2007, pp. 521, 528.
- ^ Prasad et al. 2007, pp. 23–24; Prasad et al. 2005, pp. 1179–1180; Wilson, Das Sarma & Anantharaman 2007, p. 521.
Literature cited
- von Koenigswald, W.; Goin, F.; Pascual, R. (1999). "Hypsodonty and enamel microstructure in the Paleocene gondwanatherian mammal Sudamerica ameghinoi". Acta Palaeontologica Polonica. 44 (3): 263–300.
- Krause, D. W.; Prasad, G. V. R.; von Koenigswald, W.; Sahni, A.; Grine, F. E. (1997). "Cosmopolitanism among Gondwanan Late Cretaceous mammals" (PDF). Nature. 390 (6659): 504–507. S2CID 205025618. Archived from the original(PDF) on 2010-06-11.
- Prasad, G.V.R. (2008). "Sedimentary basins & fossil records". In Singhvi, A.K.; Bhattacharya, A (eds.). Glimpses of Geoscience Research in India: The Indian Report to IUGS 2004–2008. New Delhi: The Indian National Academy of Sciences. pp. 90–96.
- Prasad, G. V. R.; Sahni, A. (2009). "Late Cretaceous continental vertebrate fossil record from India: Palaeobiogeographical insights". Bulletin de la Société Géologique de France. 180 (4): 369–381. .
- Prasad, V.; Strömberg, C. A. E.; Alimohammadian, H.; Sahni, A. (2005). "Dinosaur coprolites and the early evolution of grasses and grazers". Science. 310 (5751): 1177–1180. S2CID 1816461.
- Prasad, G.V.R.; Verma, O.; Sahni, A.; Krause, D.W.; Khosla, A.; Parmar, V. (2007). "A new late Cretaceous gondwanatherian mammal from central India". Proceedings of the Indian National Science Academy. 73 (1): 17–24.
- Wilson, G. P.; Das Sarma, D. C.; Anantharaman, S. (2007). "Late Cretaceous sudamericid gondwanatherians from India with paleobiogeographic considerations of Gondwanan mammals". Journal of Vertebrate Paleontology. 27 (2): 521–531. S2CID 130294882.