Taurovenator
| Taurovenator Temporal range: Late Cretaceous, (Cenomanian), ~
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| Reconstruction of the head of Taurovenator violantei | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Family: | †Carcharodontosauridae |
| Tribe: | †Giganotosaurini |
| Genus: | †Taurovenator Motta et al., 2016 |
| Type species | |
| †Taurovenator violantei Motta et al., 2016
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Taurovenator ("bull hunter") is a large carcharodontosaurid theropod from the late Cretaceous Huincul Formation of Argentina that lived during the Cenomanian age of the Late Cretaceous. It is monotypic, containing only one species, T. violantei.[1]
Discovery and naming
[edit]The holotype of Taurovenator (MPCA-Pv 802), a right postorbital, was discovered in the lower[2] Huincul Formation on the Violante Farm, southeast of the Ezequiel Ramos-Mexía Lake, Río Negro Province, Argentina, by Matías Motta in 2005. Taurovenator was found in the vicinity of the megaraptoran Aoniraptor, several abelisauroids, and a possible unenlagiine paravian.[1]
In 2024, a new specimen of Taurovenator (MPCA-Pv 803) was described, preserving a partial skull, a partial cervical series, several ribs, two partial forelimbs, a femur, a partial pes, and a caudal vertebra.[2] The specimen was initially described in 2016 alongside the holotype, though it was originally regarded as indeterminate.[1] Despite not overlapping in material with the holotype, this specimen was referred to Taurovenator because it was recovered from the same locality as the holotype (the specimen was found 800 metres away from the holotype's dig site) and because it and the holotype preserve features of the Giganotosaurini.[2]
The generic name Taurovenator comes from the Latin taurus ("bull"), and venator ("hunter"). The specific name honors Enzo Violante, the owner of the Violante farm where the animal was discovered.[1]
Description
[edit]
Taurovenator is a very large carcharodontosaurid. It had an estimated body mass of 5,728 kg (12,628 lb), based on a formula that utilizes the circumference of the femur to predict body mass. For reference, this is smaller than Giganotosaurus (6,349 kg), but larger than Meraxes and Mapusaurus (4,263 kg and 4,343 kg, respectively).[2][3] The skull, though incomplete, is estimated to be 135 cm in length.[2]
The holotype showed that part of the postorbital bone was strongly rugose and projected out like a horn, markedly different from the orbital bosses of other carcharodontosaurids. Both Motta et al., 2016 and Rolando et al., 2024 consider this a unique trait,[1][2] but its sister taxon Meraxes too has a postorbital that was described as laterally projecting out like a horn.[4]
Distinctively, Taurovenator's neck vertebrae bore prominent neural spines with flange-like dorsal tips. As a result, the neural spines of cervical vertebrae C3-C6 are "imbricated", ie interlocking with each other. The authors describing this morphology termed this unusual structure a "cervical complex", and likened them to overlapping roof tiles. A similar, though less extreme condition is also known in the C3-C5 of the more basal carcharodontosaurid Acrocanthosaurus.[2][5] Available information of Giganotosaurus and Mapusaurus further suggests that this "cervical complex" is a unique synapomorphy of the group. The presence of the cervical complex would have likely restricted the range of movement of the cervical vertebrae. On the other hand, the skull of Taurovenator and other carcharodontosaurids had a ball-shaped occipital condyle similar to that seen in the skulls of ceratopsian dinosaurs. This could have allowed a large range of rotational movement between the skull and the first cervical vertebra. Furthermore, the cervical complex of Taurovenator could have similar functional implications to those of the syncervical vertebrae (ie fused C1-C3 vertebrae) of ceratopsians, strengthening the anterior region of the neck, and increasing the surface area for epaxial cervico-cranial muscles.[2]
Only remains of two dorsal vertebrae are known. One is composed of a centrum, but the other is composed of a very tall, 52 cm high neural arch.[2]
Taurovenator had proportionately the smallest arms of all known allosauroids. The nearly completely preserved arms were reduced to a greater degree than even in other carcharodontosaurids, being proportionately smaller than that of taxa such as Meraxes, particularly where the forearm is concerned. Despite such limb reduction, the forearms were robust, and the digits had a great degree of flexibility. Nonetheless like other giganotosaurines, the forelimbs were likely incapable of a wide range of movement.[2]
Taurovenator also shares with Meraxes an enlarged ungual claw on the second toe, approximately 20% longer than the equivalent phalanx of the third toe and more laterally compressed.[2]
Classification
[edit]Motta et al. (2016) suggested that Taurovenator occupied a derived position within Carcharodontosauridae, comparing it to Giganotosaurus, Carcharodontosaurus and Mapusaurus in particular.[1] Coria et al. (2019) suggested that Taurovenator is synonymous with Mapusaurus, considering both of its original autapomorphies as shared with Mapusaurus and also pointing out that both taxa shared a curved lateral margin of the palpebral.[6] Additionally, the authors considered that there was a high likelihood of them being coeval,[6] however, Taurovenator is actually from the lower unit of the Huincul Formation, while Mapusaurus is from the upper unit of the formation.[2] Rolando et al. (2024) reaffirmed Taurovenator's validity, considering the autapomorphies preserved on the holotype as more strongly developed in Taurovenator than any other carcharodontosaurid, while also considering the supposedly diagnostic curved margin of the palpebral as a more widely distributed feature in Carcharodontosauridae.[2]
In order to test the systematics of Taurovenator with the information supplemented by the new specimen, the study used the phylogenetic dataset used in the description of Meraxes, with some additional data. The results of their phylogenetic analysis are shown in a cladogram below:[2][4]
Paleoenvironment
[edit]
The fossil remains of Taurovenator were recovered from the Huincul Formation, which is known for a large assemblage of dinosaurian taxa. Two other giant carcharodontosaurids were discovered from the formation as well, Mapusaurus and Meraxes, though all being found in different layers it is unlikely they are coeval.[2] Other theropods include the paravian Overoraptor, the elaphrosaurine Huinculsaurus, the abelisaurs Skorpiovenator, Tralkasaurus, and Ilokelesia, and the megaraptoran Aoniraptor.[7][8] Sauropods are the dominant herbivores of the area and are represented by the rebbachisaurid sauropods Cathartesaura and Limaysaurus along with the titanosaurs Argentinosaurus, Choconsaurus, and Chucarosaurus. [9][10][11] Ornithiscians are rarer fossil-wise, but are represented by indeterminate iguanodonts and the elasmarian Chakisaurus.[12]
See also
[edit]References
[edit]- ^ a b c d e f Motta, Matías J.; Aranciaga Rolando, Alexis M.; Rozadilla, Sebastián; Agnolín, Federico E.; Chimento, Nicolás R.; Egli, Federico Brissón; Novas, Fernando E. (June 2016). "New theropod fauna from the Upper Cretaceous (Huincul Formation) of northwestern Patagonia, Argentina". New Mexico Museum of Natural History and Science Bulletin. 71: 231–253 – via ResearchGate.
- ^ a b c d e f g h i j k l m n o Rolando, Alexis M. Aranciaga; Motta, Matías J.; Agnolín, Federico L.; Tsuihiji, Takanobu; Miner, Santiago; Brissón-Egli, Federico; Novas, Fernando E. (9 October 2024). "A new carcharodontosaurid specimen sheds light on the anatomy of South American giant predatory dinosaurs". The Science of Nature. 111 (6): 56. doi:10.1007/s00114-024-01942-4. ISSN 1432-1904.
- ^ Campione, Nicolás E.; Evans, David C.; Brown, Caleb M.; Carrano, Matthew T. (4 July 2014). Revell, Liam (ed.). "Body mass estimation in non-avian bipeds using a theoretical conversion to quadruped stylopodial proportions". Methods in Ecology and Evolution. 5 (9): 913–923. Bibcode:2014MEcEv...5..913C. doi:10.1111/2041-210X.12226. ISSN 2041-210X.
- ^ a b Canale, Juan I.; Apesteguía, Sebastián; Gallina, Pablo A.; Mitchell, Jonathan; Smith, Nathan D.; Cullen, Thomas M.; Shinya, Akiko; Haluza, Alejandro; Gianechini, Federico A.; Makovicky, Peter J. (July 2022). "New giant carnivorous dinosaur reveals convergent evolutionary trends in theropod arm reduction". Current Biology. 32 (14): 3195–3202.e5. Bibcode:2022CBio...32E3195C. doi:10.1016/j.cub.2022.05.057. PMID 35803271. S2CID 250343124.
- ^ Harrid, Jerald David (1998). A reanalysis of Acrocanthosaurus atokensis, its phylogenetic status, and paleobiogeographic implications, based on a new specimen from Texas. New Mexico Museum of Natural History and Science (published 1 January 1998).
- ^ a b Coria, Rodolfo A.; Currie, Philip J.; Ortega, Francisco; Baiano, Mattia A. (2019). "An Early Cretaceous, medium-sized carcharodontosaurid theropod (Dinosauria, Saurischia) from the Mulichinco Formation (upper Valanginian), Neuquén Province, Patagonia, Argentina". Cretaceous Research. 111: 104319. doi:10.1016/j.cretres.2019.104319.
- ^ Matías J. Motta; Federico L. Agnolín; Federico Brissón Egli; Fernando E. Novas (2020). "New theropod dinosaur from the Upper Cretaceous of Patagonia sheds light on the paravian radiation in Gondwana". The Science of Nature. 107 (3): Article number 24. Bibcode:2020SciNa.107...24M. doi:10.1007/s00114-020-01682-1. hdl:11336/135530. PMID 32468191. S2CID 218913199.
- ^ Cerroni, M.A.; Motta, M.J.; Agnolín, F.L.; Aranciaga Rolando, A.M.; Brissón Egli, F.; Novas, F.E. (2020). "A new abelisaurid from the Huincul Formation (Cenomanian-Turonian; Upper Cretaceous) of Río Negro province, Argentina". Journal of South American Earth Sciences. 98: 102445. Bibcode:2020JSAES..9802445C. doi:10.1016/j.jsames.2019.102445. S2CID 213781725.
- ^ Calvo, Jorge O.; Salgado, Leonardo (1995). "Rebbachisaurus tessonei sp. nov. a new Sauropoda from the Albian-Cenomanian of Argentina; new evidence on the origin of the Diplodocidae" (PDF). Gaia. 11: 13–33. Archived from the original (PDF) on 23 September 2021.
- ^ Baiano, Mattia A.; Coria, Rodolfo A.; Cau, Andrea (June 2020). "A new abelisauroid (Dinosauria: Theropoda) from the Huincul Formation (lower Upper Cretaceous, Neuquén Basin) of Patagonia, Argentina". Cretaceous Research. 110: 104408. Bibcode:2020CrRes.11004408B. doi:10.1016/j.cretres.2020.104408. S2CID 214118853.
- ^ Agnolin, Federico L.; Gonzalez Riga, Bernardo J.; Aranciaga Rolando, Alexis M.; Rozadilla, Sebastián; Motta, Matías J.; Chimento, Nicolás R.; Novas, Fernando E. (2 February 2023). "A new giant titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous of Northwestern Patagonia, Argentina". Cretaceous Research. 146: 105487. Bibcode:2023CrRes.14605487A. doi:10.1016/j.cretres.2023.105487. ISSN 0195-6671.
- ^ Alvarez-Nogueira, Rodrigo; Rozadilla, Sebastián; Agnolín, Federico L.; Garcia Marsà, Jordi A.; Motta, Matias J.; Novas, Fernando E. (11 March 2024). "A new ornithopod from the Upper Cretaceous (Huincul Formation) of Northwestern Patagonia, Argentina. Implications on elasmarian postcranial anatomy". Cretaceous Research. 159 (In press): 105874. Bibcode:2024CrRes.15905874N. doi:10.1016/j.cretres.2024.105874.
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