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Sunday, November 22, 2020

Your Friends The Titanosaurs, part 30: Titanosaurus of India and Madagascar

My original plan was to cover Titanosaurus indicus plus the seven species that hadn't been otherwise included; overstuffed for Thanksgiving, if you like. After 4,500 words, not counting the 46 references, I thought that might be a little too overstuffed. So, I've decided to split the post in two. Today covers just T. indicus and the three other dubious species from India or Madagascar ("T." blanfordi, "T." madagascariensis, and "T." rahioliensis). Later this week, I'll put up the other half, which will take us to Argentina ("T." nanus), England ("T." lydekkeri and "T." valdensis), and Laos ("T." falloti). As usual, house rules apply: indeterminate species have gone back to their original genus and get quotation marks.

A few general remarks before we get started: Titanosaurus is notorious for the numerous far-flung species that have been attached to it (Wilson and Upchurch 2003). We've already seen the cream of the crop, the species which are still considered to be valid or potentially valid, albeit under different genera: Titanosaurus australis (Neuquensaurus), Titanosaurus colberti (Isisaurus), Titanosaurus dacus (Magyarosaurus), and Titanosaurus robustus (Neuquensaurus), plus Laplatasaurus araukanicus, which has sometimes been considered a species of Titanosaurus (e.g., Powell 2003). Let us not forget Titanosaurus montanus either, although technically it doesn't count because it was supposed to be a different genus; O. C. Marsh just came up with the idea of naming a sauropod Titanosaurus the same year that Richard Lydekker did. Anyway, this leaves us with the type species T. indicus and seven dubious species, not all of which are necessarily even titanosaurs. This doesn't get into another pool of fossils identified as Titanosaurus sp., but these are being left out here. If you'd like to delve into those, Wilson and Upchurch (2003) also address them. (One of the examples they address, also known as DGM Series C, later became Baurutitan britoi.)

Why were so many species attributed to Titanosaurus? My guess is there were several factors. First, paleontologists of the 19th century and early 20th century were more apt to add new species to existing genera than paleontologists today. Second, there wasn't much known about sauropods at the time, and almost all of what was known pertained to North American Jurassic sauropods. Third, Titanosaurus indicus is a blank canvas. Outside of characteristics that are now known to be widely distributed among titanosaurs, such as procoelous caudals, there wasn't much to define it. The great majority of the other Titanosaurus species are based on pretty scrappy material. Once the ball got rolling, the definition of Titanosaurus began to stretch and grow to accommodate the various new species, creating a positive feedback loop.

Titanosaurus indicus

Let's start off with some good news: the holotype caudals of T. indicus and "T." blanfordi are no longer lost; they'd just wound up in the invertebrate collections of the Geological Survey of India (Mohabey et al. 2013).

Titanosaurus indicus, the original titanosaur, has a lengthy history (see Wilson and Upchurch 2003, Carrano et al. 2010, or Mohabey et al. 2013 for summaries). The fossils that became the holotype of this genus and species were collected circa 1828 from Bara Simla at Jabalpur, Madhya Pradesh, central India by William Henry Sleeman, in the years before he did the other things that made him famous. I'm not sure, but this may be the only case of a dinosaur holotype being collected by someone who was eventually knighted. (Yes, there's Sir Richard Owen, but I was under the impression people sent him fossils rather than him having to get them himself.) We have a report of the provenance from Sleeman himself (Sleeman 1844), although the exact stratigraphic position in the Lameta Formation is uncertain (Wilson and Upchurch 2003, who favor the "sauropod bed" horizon). Sleeman gave two fossil bones to a surgeon, G. G. Spilsbury, who visited Bara Simla and collected another bone. These specimens were then given to antiquarian James Prinsep in 1832 and then to Dr. Thomas Oldham, Director of the Geological Survey of India. Finally they went to someone with paleontological expertise, Hugh Falconer, who briefly documented them in 1862, in a memo that went unpublished in his lifetime (Falconer 1868). At this early stage the distinctly procoelous vertebrae, the two pairs of processes for the chevrons, and the absence of articulation points for the prezygapophyses drew attention.

Three views of one of the two original T. indicus caudals, modified slightly from Falconer (1868) to remove adjacent figured fossils.

Whether or not Falconer had any grander plans for these specimens is not known, but his death prevented him from further work on them. It would fall to Richard Lydekker, who was born 21 years after the specimens were likely found, to finish the descriptive work (Lydekker 1877). To the original caudals, Lydekker also appended a femur found at Bara Simla in 1871. This bone plays a minimal role in the future of T. indicus, as it came from a different horizon of the Lameta Formation (Matley 1921). Huene and Matley (1933) later assigned it to Antarctosaurus sp., which to be honest doesn't help that much but at least is a choice of a genus based on material including a definitely associated femur. Concerning the name, it is simple enough to figure out what the "indicus" refers to. Lydekker chose Titanosaurus for the size of the animal, although this is somewhat deflated when we read his statement that "our Indian species must have been nearly as large as the English giant", the "English giant" being that notably large sauropod Cetiosaurus. (He elsewhere notes that the femur is smaller than that of "Professor Phillip's" Cetiosaurus, a.k.a. Cetiosaurus oxoniensis. Yes, there was once a time when Cetiosaurus oxoniensis was a giant sauropod.) Anyway, the name can be translated as something like "Indian titan lizard".

As his use of Cetiosaurus as a giant sauropod shows, Lydekker didn't have a lot of options for comparison at the time. Had he published it a few years later, he would have had plenty from the Morrison Formation of the United States, but he also wouldn't have been able to use "Titanosaurus," since O. C. Marsh later that very year came up with Titanosaurus montanus. More than a century later, something similar would happen with the name "Ultrasaurus", in which the sauropod that was named first and thus kept the name was smaller than the one that was named second, but I digress. At any rate, he found his Titanosaurus to be most comparable to Pelorosaurus and Cetiosaurus. He gave a pretty thorough diagnosis of the new species, especially considering the very limited nature of the material. The catch, though, is that all of the features he noticed are now known to be more widely distributed throughout Titanosauria (Wilson and Upchurch 2003), which does lead to the observation that Titanosaurus indicus was not unusually specialized in the tail. About the most we can say is that the type vertebrae are of laterally compressed and slender build.

Lydekker also mentioned that there were a "considerable series of caudal vertebrae of this genus" in the collections of the Indian Museum, obtained by a "Mr. W. T. Blanford" from the Lameta of Pisdura, some 320 km (200 mi) to the south of Jabalpur. Within a couple of years he'd decided that Blanford's material warranted its own species, T. blanfordi (Lydekker 1879), getting the ball rolling on the multiplicity of Titanosaurus species. Little would be heard concerning the Indian titanosaur material until Charles Matley began sustained work at Bara Simla in 1917, which he would document with Friedrich von Huene for their 1933 monograph, and which brings us back to the extended discussion on the Jainosaurus septentrionalis entry. No great advances on the eternal Jainosaurus/Titanosaurus question have been made since that entry, although I will say it's interesting that both times Matley thought he had a Titanosaurus skeleton, someone later identified the material as Antarctosaurus (=Jainosaurus) septentrionalis (Huene and Matley 1933 for Bara Simla; Wilson et al. 2011 for Chhota Simla).

Realistically, short of someone finding some heretofore-unknown information that could definitively show that the Bara Simla titanosaur fossils belong to one individual representing T. indicus, or the discovery of at least one new diagnostic feature on the type material, the only way to re-establish T. indicus as more than a historical curiosity is get a large sample of Lameta titanosaur tails (ideally with other parts of the titanosaurs attached). If it doesn't turn out that two or more otherwise distinct titanosaur species share T. indicus-type caudals, you might be onto something.

"Titanosaurus" blanfordi

Somewhere in my internal filing system is a very stubborn process, operating at an unconscious level, that insists this species is spelled blandfordi. It usually ends up getting its way.

Anyway, "T." blanfordi was named in Lydekker (1879) for two caudal vertebrae recovered from Pisdura by W. T. Blanford, which he'd previously attributed to T. indicus (Lydekker 1877). One of the two was elongated and cylindrical, the other more equant (and, of course, to increase the difficulty neither came with a neural arch). He later considered the possibility that blanfordi deserved its own genus (Lydekker 1887), but did not take that step. Charles Matley made additional collections at Pisdura in 1920. The issues with the titanosaur collections from Bara Simla rightly cause frustration, but it's not as if the Pisdura specimens got off any easier: Huene and Matley (1933) divided the specimens among Titanosaurus indicus, T. blanfordi, Antarctosaurus sp., cf. Laplatasaurus madagascariensis, and the obligatory indeterminate sauropod.

Plate V from Lydekker (1879), with larger numbers added for clarity. 1 & 2 and 4 & 5 are views of the two vertebrae assigned to "T." blanfordi, while 3 is an anterior view of the holotype T. indicus caudal and 6 & 7 are two views of an "Ichthyosaurus" indicus caudal vertebra. The vertebra pictured as 1 & 2 was assigned to cf. Laplatasaurus madagascariensis by Huene ("Titanosaurus" madagascariensis below), leaving the elongated specimen illustrated as 4 & 5 as the holotype of blanfordi.

Von Huene did one thing that was helpful, in a roundabout way: he transferred the equant vertebra to cf. Laplatasaurus madagascariensis (Huene 1929), leaving the distinctive elongate caudal from Lydekker's original type material. Oddly enough, in Huene and Matley (1933) a few more equant caudals from Pisdura found their way into blanfordi, as well as postcranial bits which really had no business being referred to a species known only from caudals. Jain and Bandyopadhyay (1997) removed all of this additional material (to cf. L. madagascariensis, back to being Titanosaurus madagascariensis in their paper), reducing blanfordi to that one elongate caudal. As for that specimen, it shows various typically titanosaurian traits (strongly procoelous, base of neural arch positioned anteriorly, etc.), but is basically an elongate but not otherwise particularly unusual middle caudal centrum, representing an indeterminate titanosaur (Wilson and Upchurch 2003).

"Titanosaurus" madagascariensis

We briefly met "T." madagascariensis back in 2019 as the Ur-example of titanosaurian osteoderms. While I would love to tell you that after titanosaurian armor was accepted, "T." madagascariensis went on to become a scientifically well-regarded species, this did not happen. At the end of the day it was still "T." madagascariensis, scientifically based on two caudals and a humerus. Some species can get by with two caudals and a humerus, but not this one, for reasons which will become clear.

"T." madagascariensis was described in Depéret (1896); no points for guessing the meaning of the species name. The bones, along with various other fossils, were primarily obtained for Depéret by Sergeant-Major Landillon under instructions from Dr. Félix Salètes, engaged in installing a hospital in the Maevarana area. The titanosaur fossils were found in a clay or clayey sandstone (=Maevarano Formation) making up the lower slopes of the plateau country there, with most of them found at one locality. Depéret gave much more detailed provenance information than your average late 19th century paleontologist, and waxed optimistically on the paleontological potential of the formation, which would be borne out by expeditions a century later. Depéret described a partial humerus and two anterior caudals as Titanosaurus madagascariensis, and tentatively placed what we would now recognize as a titanosaur osteoderm in the same species, mostly on the basis of association with the caudals. The caudals are now cataloged as UCB 92829 and UCB 92305 (Université Claude Bernard, Lyon, France), the partial humerus as UCB 92831, and the osteoderm as UCB 92827 (Curry Rogers and Forster 2004). At that time, the only named sauropod known to Depéret that also had procoelous anterior caudals and caudal neural arches positioned near the anterior end of the centrum was Titanosaurus, so logically enough the new species was assigned to it. Depéret regarded a caudal that was eventually named "Titanosaurus" valdensis to be particularly similar to the caudals of the new species. Thevenin (1907) added some additional vertebrae and limb elements.

Depéret (1896)'s plate illustrating the type material of "Titanosaurus" madagascariensis and what eventually became Majungasaurus crenatissimus. "T." madagascariensis is represented by items 1-1a, 2-2a, and 3-3a, and M. crenatissimus gets the rest.

"T." madagascariensis was not to remain in Titanosaurus for long: von Huene, preparing his vast monograph on Argentina's dinosaurs (Huene 1929), had access to a much greater sample of titanosaurian remains, and concluded that "T." madagascariensis was more similar to one of his amalgamated titanosaurs, Laplatasaurus araukanicus, classifying it as cf. Laplatasaurus madagascariensis. As we saw back in L. araukanicus's entry, von Huene had assigned plenty of bones to Laplatasaurus, including caudals, so there was no shortage of seemingly comparable material; the problem was the limited evidence for assigning those bones to Laplatasaurus in the first place (Gallina and Otero 2015). As mentioned above, he then took the step of placing one of the two type caudals of "Titanosaurus" blanfordi in cf. L. madagascariensis, introducing another species into the increasingly crowded Pisdura bonebed. If you've ever wondered why Laplatasaurus is placed in India and Madagascar in old dinosaur books, this is your answer. Huene and Matley (1933) placed additional Indian material (a sacral and three caudals from Pisdura) in cf. L. madagascariensis. Eventually, though, it drifted back to Titanosaurus (McIntosh 1990; Jain and Bandyopadhyay 1997).

Beginning in the 1990s, the Maevarano Formation was the source of many more titanosaur specimens, some of which have been described as Rapetosaurus krausei or Vahiny depereti (not yet covered). Why has "T." madagascariensis been left out of the fun? It goes back to the two caudals of the original type material. It turns out that two titanosaur species can definitely be distinguished in the Maevarano fossils, and Depéret's two caudals include one from each. Specifically, UCB 92829 is a Rapetosaurus caudal (Curry Rogers and Forster 2001), and UCB 92305 belongs to the other one, which has been known for some time as "Malagasy Taxon B" (Curry Rogers and Forster 2004; Curry Rogers and Wilson 2014). "All right then," you say. "We make UCB 92305 the lectotype of madagascariensis, slap on a new genus name, and everything's cool." That's one way of handling it. The complication is that although we know there is at least one non-Rapetosaurus titanosaur in the Maevarano, the scarcity of associated or articulated material means that we can't be *sure* that all of the non-Rapetosaurus stuff goes to one species, and of course titanosaurs delight in multiplicity. So, for the moment, we are left with Rapetosaurus krausei, Vahiny depereti, and Malagasy Taxon B/part of "Titanosaurus" madagascariensis, although presumably there could be a future with Vahiny madagascariensis.

This still leaves us with the Indian material, which Jain and Bandyopadhyay (1997) increased with the referral of all of the Pisdura "T." blanfordi specimens described in Huene and Matley (1933) (a caudal, a tibia, a metacarpal, and a possible scapula fragment). Conveniently enough, von Huene based his own assignment of Indian material to cf. Laplatasaurus madagascariensis on UCB 92305 (Curry Rogers and Wilson 2014), which would ally it to Malagasy Taxon B. Although I am skeptical that the Indian material represents the same species as Malagasy Taxon B, you *could* make an argument for as many as four titanosaur species in the Lameta Formation based on middle caudals: flat-sided (T. indicus), cylindrical and elongate ("T." blanfordi), squarish ("T." "madagascariensis"), and waisted (Isisaurus) (Jain and Bandyopadhyay 1997). Honestly, despite the current widespread Isisaurus/Jainosaurus model, there's no a priori reason to reject the possibility of more titanosaur species in the Lameta. It's not inconsistent with other titanosaur-bearing formations; there's no evidence for any other herbivores of any size taking up ecospace (unless you have faith in the lovely doorstop named Brachypodosaurus gravis); and we really don't know how large the landmass was at the end of the Cretaceous, given that India was at that time in the process of bidding farewell to what became the Seychelles, and some not-insubstantial region of real estate has since become crumpled into the Himalayas. Again, what are needed are good titanosaur tails, to show the extent of variation.

"Titanosaurus" rahioliensis

"T." rahioliensis comes from Rahioli, Gujarat, western India, also home to a titanosaur egg bed (Mathur and Srivastava 1987; Wilson and Upchurch 2003). The egg-bearing horizon is regarded as correlating to the main Lameta Formation limestone at Bara Simla, while titanosaur bones have been found in abundance in the overlying sandstone (Wilson and Upchurch 2003). "T." rahioliensis is based on a series of teeth cataloged as GSI 19,997 to 20,007 (Geological Survey of India, Kolkata, India) (Mathur and Srivastava 1987), but the specimens are now missing, leaving only photographs to go on (Wilson and Upchurch 2003). The species name refers to Rahioli (Mathur and Srivastava 1987), giving us something like "titan lizard from Rahioli". Mathur and Srivastava (1987) only tentatively referred the species to Titanosaurus, mostly on the basis of Titanosaurus being the "characteristic Upper Cretaceous sauropod genus from Madhya Pradesh and the study area." Given that Titanosaurus indicus is only known from caudals, there's no overlap and no reason to keep them in the same genus. Isisaurus and Jainosaurus have since been reported from Rahioli (Wilson et al. 2019), making them candidates as well.

The photographed teeth are of the long, slender, pencil-like variety, slightly curved, with D-shaped cross-sections near the tip and faint longitudinal ridges at the crown. About the only thing notable about these teeth is that the enamel is thicker on the lip side (labial) than the tongue side (lingual) (Mathur and Srivastava 1987; Wilson and Upchurch 2003). This is uncommon in sauropods; when Wilson and Upchurch (2003) made their review of Titanosaurus species, this was only known in the rebbachisaurid Nigersaurus. This characteristic has since been reported in other forms, including Bonitasaura salgadoi (Gallina and Apesteguía 2011) and a tooth from the "Continental Intercalaire" of Algeria, BSPG 1993 IX 2A (Holwerda et al. 2018). There isn't a lot to go on, but I wonder if the asymmetric distribution of enamel could be a feature correlated with the same environmental pressures that produced a partly to fully squared-off jaw.

"T." rahioliensis has been considered indeterminate almost since the time it was named (McIntosh 1990). Wilson and Upchurch (2003) assigned it no farther than Neosauropoda. Malkani (2019a, 2019b) suggested that the teeth came from a "gspsaurid" based on the reprinted photos in Wilson and Upchurch (2003). Curiously, although the reprinted caption to the figure states that the photos are different views of one tooth (GSI 20,006), as in Wilson and Upchurch (2003), the text of Malkani (2019a, 2019b) seems to have misinterpreted the figure as showing two teeth, one of which is described as more like those of Gspsaurus pakistani, the other more like Saraikimasoom vitakri. No information has been given on the enamel thicknesses for these forms.

References

Carrano, M. T., J. A. Wilson, and P. M. Barrett. 2010. The history of dinosaur collecting in central India, 1828–1947. Pages 161–173 in R. T. J. Moody, E. Buffetaut, D. Naish, and D. M. Martill, editors. Dinosaurs and other extinct saurians: a historical perspective. Geological Society of London, London, United Kingdom. Special Publication 343.

Curry Rogers, K., and C. A. Forster. 2001. The last of the dinosaur titans: a new sauropod from Madagascar. Nature 412 (6846):530–534.

Curry Rogers, K., and C. A. Forster. 2004. The skull of Rapetosaurus krausei (Sauropoda: Titanosauria) from the Late Cretaceous of Madagascar. Journal of Vertebrate Paleontology 24(1):121–144.

Curry Rogers, K., and J. A. Wilson. 2014. Vahiny depereti, gen. et sp. nov., a new titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous Maevarano Formation, Madagascar. Journal of Vertebrate Paleontology 34(3):606–617.

Depéret, C. 1896. Note sur le dinosauriens sauropodes et théropodes du Crétacé Supérieur de Madagascar. Bulletin de la Société Géologique de France 24:176–194. [translated]

Falconer, H. 1868. Notes on fossil remains found in the Valley of the Indus below Attock, and at Jubbulpoor. Pages 414–419 in C. Murchison, editor. Palaeontological memoirs and notes of the late Hugh Falconer, vol. I. Fauna Antiqua Sivalensis. Robert Hardwicke, London.

Gallina, P. A., and S. Apesteguía. 2011. Cranial anatomy and phylogenetic position of the titanosaurian sauropod Bonitasaura salgadoi. Acta Palaeontologica Polonica 56(1):45–60.

Gallina, P. A., and A. Otero. 2015. Reassessment of Laplatasaurus araukanicus (Sauropoda: Titanosauria) from the Upper Cretaceous of Patagonia, Argentina. Ameghiniana 52:487–501. doi:10.5710/AMGH.08.06.2015.2911.

Holwerda, F. M., V. Díez Díaz, A. Blanco, R. Montie, and J. W. F. Reumer. 2018. Late Cretaceous sauropod tooth morphotypes may provide supporting evidence for faunal connections between North Africa and southern Europe. PeerJ 6:e5925 doi:10.7717/peerj.5925.

Huene, F. von. 1929. Los Saurisquios y Ornitisquios del Cretáceo Argentino. Anales del Museo de La Plata 3:1–196.

Huene, F. von, and C. A. Matley. 1933. The Cretaceous Saurischia and Ornithischia of the central provinces of India. Palaeontologia Indica 21:1–74.

Jain, S. L., and S. Bandyopadhyay. 1997. New titanosaurid (Dinosauria: Sauropoda) from the Late Cretaceous of central India. Journal of Vertebrate Paleontology 17(1):114–136.

Lydekker, R. 1877. Notices of new and other Vertebrata from Indian Tertiary and Secondary rocks. Records of the Geological Survey of India 10(1):30–43.

Lydekker, R. 1879. Indian pre-Tertiary Vertebrata. Part 3. Fossil Reptilia and Batrachia. Palaeontologica Indica (series 4) 1:20–33.

Lydekker, R. 1887. On certain dinosaurian vertebrae from the Cretaceous of India and the Isle of Wight. Quarterly Journal of the Geological Society of London 43:156–160.

Malkani, M. S. 2019a. Titanosaurus indicus, Titanosaurus blanfordi, Antarctosaurus septentrionalis, Jainosaurus septentrionalis, Laplatasaurus madagascariensis and Titanosaurus rahioliensis titanosaurs from India; their guide fossils affinity to recent valid titanosaurs Isisaurus, Pakisaurus, Saraikimasoom and Gspsaurus from Indo-Pakistan. Researchgate.net. Research. 40 pages.

Malkani, M. S. 2019b. Comparison of Pakistani and Indian titanosaurs; Diversity of skull rostrum and braincases, vertebral and limb fossils. Researchgate.net. Research. 144 pages.

Mathur, U. B., and S. Srivastava. 1987. Dinosaur teeth from Lameta Group (Upper Cretaceous) of Kheda district, Gujarat. Journal of the Geological Society of India 29:544–566.

Matley, C. A. 1921. On the stratigraphy, fossils and geological relationships of the Lameta Beds of Jubbulpore. Records of the Indian Geological Survey 53:142–164.

McIntosh, J. S. 1990. Sauropoda. Pages 345–401 in D. B. Weishampel, P. Dodson, and H. Osmólska, editors. The Dinosauria. University of California Press, Berkeley, California.

Mohabey, D. M., S. Sen, and J. A. Wilson. 2013. India's first dinosaur, rediscovered. Current Science 104(1):34–37.

Powell, J. E. 2003. Revision of South American titanosaurid dinosaurs: palaeobiological, palaeobiogeographical, and phylogenetic aspects. Records of the Queen Victoria Museum 111.

Sleeman, W. H. 1844. Rambles and recollections of an Indian official. J. Hatchard and Son, London, United Kingdom.

Thevenin, A. 1907. Paléontologie de Madagascar. Annales de Paléontologie 2:121–136.

Wilson, J. A., and P. Upchurch. 2003. A revision of Titanosaurus Lydekker (Dinosauria – Sauropoda), the first dinosaur genus with a "Gondwanan" distribution. Journal of Systematic Palaeontology 1(3):125–160.

Wilson, J. A., P. M. Barrett, and M. T. Carrano. 2011. An associated partial skeleton of Jainosaurus cf. septentrionalis (Dinosauria: Sauropoda) from the Late Cretaceous of Chhota Simla, central India. Palaeontology 54(5):981–998.

Wilson, J. A., D. M. Mohabey, P. Lakra, and A. Bhadran. 2019. Titanosaur (Dinosauria: Sauropoda) vertebrae from the Upper Cretaceous Lameta Formation of western and central India. Contributions of the Museum of Paleontology, University of Michigan 33(1):1–27.

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