Bruhathkayosaurus

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Bruhathkayosaurus
Temporal range:
Ma
↓
Speculative
life restoration
of Bruhathkayosaurus
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: †Sauropodomorpha
Clade: †Sauropoda
Clade: †Macronaria
Clade: †Titanosauria
Genus: †Bruhathkayosaurus
Yadagiri & Ayyasami, 1987
Species:
†B. matleyi
Binomial name
†Bruhathkayosaurus matleyi
Yadagiri & Ayyasami, 1987

Bruhathkayosaurus (

titanosaur Argentinosaurus,[1] as longer than 35 metres (115 ft) and weighing over 80 tonnes. A 2023 estimate placed Bruhathkayosaurus as potentially weighing approximately 110–170 tonnes (110–170 long tons; 120–190 short tons). If the upper estimates of the 2023 records are accurate, Bruhathkayosaurus may have rivalled the blue whale as one of the largest animals to ever exist.[2] However, all of the estimates are based on the dimensions of the fossils described in Yadagiri and Ayyasami (1987), and in 2017, it was reported that the holotype fossils had disintegrated and no longer exist.[3][4]

Discovery and naming

The

palaeontologist Charles Alfred Matley
, who discovered many fossils in India.

The monsoon season, combined with the sands and clays of the Kallamedu Formation, creates water-saturated fossils which are very friable. During the dry season, expansion during the day and contraction during the night can cause fossils to split apart. This results in poorly preserved bones that can be impossible to extract without damage. In 2017, Galton and Ayyasami reported that the Bruhathkayosaurus fossils started to disintegrate inside their field jackets before reaching the Geological Survey of India (GSI) and no longer exist.[4]

Classification

Bruhathkayosaurus was originally classified as a

titanosaur sauropod.[6] Some later studies listed Bruhathkayosaurus as an indeterminate sauropod or as a nomen dubium.[7][8][9]

The original publication described little in the way of diagnostic characteristics and was only supported by a few line drawings and photographs of the fossils as they lay in the ground. This led to online speculation by researchers that the bones might actually have been petrified wood, akin to the way the original discoverers of Sauroposeidon initially believed their find to be fossilized tree trunks.[10][11][12] A 2022 review by Pal and Ayyasami presented additional previously unseen photographs of the tibia bone at the excavation site and in a plaster jacket, and reinforced the taxon's position within Titanosauria.[13] However, as Mohabey and colleagues noted in 2024, "this new information has not resolved the identity of the element nor the validity of the taxon."[14]

Size estimates

According to the published description, the shin bone (tibia) of Bruhathkayosaurus was 2 m (6.6 ft) long.[3][13] This is 29 percent larger than the fibula of Argentinosaurus, which is only 1.55 m (5.1 ft) long. The fragmentary femur was similarly huge; across the distal end, it measured 75 cm (2.46 ft), 33% larger than the femur of Antarctosaurus giganteus, which measures 56 cm (1.84 ft). The ilium measured 1.2 m (3.9 ft) in length.[15][4]

No total body size estimates for Bruhathkayosaurus have been published, but paleontologists and researchers have posted tentative estimates on the Internet. In a post from June 2001, Mickey Mortimer estimated that Bruhathkayosaurus could have reached 44.1 m (145 ft) in length and might have weighed 175–220 t (193–243 short tons), but in later posts retracted these estimates, reducing the estimated length to 28–47 m (92–154 ft) based on more complete titanosaurs (

weblog Sauropod Vertebra Picture of the Week, paleontologist Matt Wedel used a comparison with Argentinosaurus and calculated the weight of Bruhathkayosaurus at up to 126 metric tons (139 short tons).[18] In 2019, Gregory S. Paul suggested that the supposed tibia was probably a degraded femur, in which case its length was slightly greater than that of Dreadnoughtus (1.91 meters) and Futalognkosaurus (1.98 meters). Its ilium is similar in length to that of Dreadnoughtus whereas the width of the distal femur appears to slightly exceed that of Patagotitan. Paul estimated its mass at around 30–55 t (33–61 short tons), much lower than any previous estimation.[19] In 2020, Molina-Perez and Larramendi suggested that the 2 m (6.6 ft) long tibia is probably a fibula, and estimated the size of the animal at 37 m (121 ft) and 95 metric tons (105 short tons).[20]

By comparison, the titanosaur Argentinosaurus is estimated to have reached 35 m (115 ft) in length, and to have weighed 65–100 tonnes.

fossil record. In addition, isometric scaling is based on the assumption that body proportions remain the same, which is not necessarily the case. In particular, the proportions of the titanosaurs are not well known, due to a limited number of relatively complete specimens.[15]

If the upper size estimates for Bruhathkayosaurus are accurate, it would even rival the size of the largest recorded blue whale. Mature blue whales can reach 30 m (98 ft) in length, and the record-holder blue whale was recorded at 173 tonnes (190 short tons),[22] with estimates of up to 199 tonnes (220 short tons).[23]

Another poorly known sauropod that shares similar size estimates to Bruhathkayosaurus is Maraapunisaurus fragillimus, which is based on a now-missing dorsal vertebra. In 2006, Kenneth Carpenter used Diplodocus as a guide and estimated Maraapunisaurus to be 58 m (190 ft) in length and weigh only about 122.4 metric tons (130 short tons).[24] In 2018, however, Carpenter estimated Maraapunisaurus to be 30–32 m (98–105 ft) in length based upon comparisons with rebbachisaurids.[25] In 2019, Paul gave a higher estimation of 35 to 40 metres (115 to 131 ft) and a weight of 80 to 120 tonnes (88 to 132 short tons).[19]

Paul and Larramendi (2023) suggested that Bruhathkayosaurus may have weighed within the range of 110–170 tonnes (120–190 short tons), though they stated that it would have likely weighed between 110 and 130 tonnes (120 and 140 short tons). Whilst its most liberal estimate was 240 tons when scaled with Patagotitan, they considered any estimate over 170 tonnes (190 short tons) to be unlikely.[2]

See also

References

  1. ^ a b Paul, Gregory S. (Autumn 1994). "Big Sauropods - Really, Really Big Sauropods" (PDF). The Dinosaur Report. The Dinosaur Society. pp. 12–13. Retrieved 14 November 2011.
  2. ^
    S2CID 259782734
    .
  3. ^ a b c Yadagiri, P. and Ayyasami, K. (1987). "A carnosaurian dinosaur from the Kallamedu Formation (Maestrichtian horizon), Tamilnadu." In M.V.A. Sastry, V.V. Sastry, C.G.K. Ramanujam, H.M. Kapoor, B.R. Jagannatha Rao, P.P. Satsangi, and U.B. Mathur (eds.), Three Decades of Development in Palaeontology and Stratigraphy in India. Volume 1. Precambrian to Mesozoic. Geological Society of India Special Publication, 11(1): 523-528.
  4. ^
    ISSN 0077-7749
    .
  5. ^ Schneiderman, P. (Nov 1994). "Report on the initial description". Dinosaur Mailing List
  6. ^ Chatterjee, S. (1995). "The last dinosaurs of India". The Dinosaur Report, Fall 1995. p. 12-18.
  7. ^ Upchurch, P., Barrett, P. M. and Dodson, P. 2004. Sauropoda. pp. 259–322. in Weishampel, D. B., Dodson, P. and Osmólska, H. (eds). The Dinosauria, Second Edition. University of California Press, Berkeley, 861 pp.
  8. S2CID 9166607
    .
  9. PMID 26888916
    .
  10. ^ Holtz, T. (1995), http://dml.cmnh.org/1995Sep/msg00701.html Archived 11 November 2011 at the Wayback Machine "Re: Biggest predators"], discussion group, The Dinosaur Mailing List, 22 September 1995. Accessed 24 February 2019.
  11. ^ Mortimer, M. (2006), "Re:" Archived 19 November 2011 at the Wayback Machine, discussion group, The Dinosaur Mailing List, 17 November 2006. Accessed 24 February 2019.
  12. ^ Brusatte, S. (2001), "Re: Bruhathkayosaurus" Archived 7 January 2009 at the Wayback Machine, discussion group, The Dinosaur Mailing List, 18 June 2001. Accessed 24 February 2019.
  13. ^
    S2CID 250056201
    .
  14. ISSN 0272-4634
    .
  15. ^ a b c Mortimer, M. (2004), "Re: Largest Dinosaurs" Archived 13 September 2019 at the Wayback Machine, discussion group, The Dinosaur Mailing List, 7 September 2004. Accessed 23 May 2008.
  16. ^ Mortimer, M. (2001), "Re: Bruhathkayosaurus", discussion group, The Dinosaur Mailing List, 19 June 2001. Accessed 23 May 2008.
  17. ^ Mortimer, M. (2001), "Titanosaurs too large?" Archived 3 March 2016 at the Wayback Machine, discussion group, The Dinosaur Mailing List, 12 September 2001. Accessed 23 May 2008.
  18. ^ Wedel, M. "SV-POW! showdown: sauropods vs whales." [Weblog entry.] Sauropod Vertebra Picture of the Week. 20 May 2008. Accessed 23 May 2008.
  19. ^
    S2CID 210840060. Archived
    (PDF) from the original on 29 September 2022.
  20. Bibcode:2020dffs.book.....M
    .
  21. ^ Paul, Gregory S. (1997). "Dinosaur models: the good, the bad, and using them to estimate the mass of dinosaurs". In Wolberg, D. L.; Stump, E.; Rosenberg, G. D. (eds.). DinoFest International Proceedings. The Academy of Natural Sciences. pp. 129–154.
  22. ^ "Assessment and Update Status Report on the Blue Whale Balaenoptera musculus" (PDF). Committee on the Status of Endangered Wildlife in Canada. 2002. Retrieved 19 April 2007.
  23. PMID 25649000
    .
  24. ^ Carpenter, K. (2006). "Biggest of the big: a critical re-evaluation of the mega-sauropod Amphicoelias fragillimus." In Foster, J.R. and Lucas, S.G., eds., 2006, Paleontology and Geology of the Upper Jurassic Morrison Formation. New Mexico Museum of Natural History and Science Bulletin 36: 131–138.
  25. S2CID 210973474
    .

External links
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