Pyroraptor
Pyroraptor was presumably a dromaeosaurid or unenlagiid dinosaur genus which lived approximately 70.6 million years ago. It is known only from a partial skeleton which was found in Provence (France) in 1992. It was scientifically described only in 2000, and named as Pyroraptor olympius.[1] Due to its fragmentary fossil remains, we have only few information regarding the appearance and biology of the species, and its taxonomic position is also uncertain.
Pyroraptor olympius. By Mette Aumala - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=116449372
Known occurrences of Pyroraptor olympius fossils.
Discovery and fossil remains
Pyroraptor was discovered in the south-eastern region of France, in Provence, at the La Boucharde locality of the Arc Basin in. The meaning of the genus name is "Fire thief", as its fossils were found after a forest fire in 1992. The species name refers to Mont Olympe, which is a mountain in Provence, near the place where the fossils were explored. A holotype specimen and paratypes were described from this location, all of them were quite fragmentary. The holotype specimen only has the second toe claw of the left foot, while the paratypes consisted of the equivalent claw of the right foot, a more complete second toe claw, a right ulna, a left second metatarsal, and two teeth as well.
From two locations of Spain, from the Vitória Formation and the Tremp Group, additional material was assigned to Pyroraptor. These further material consists of five pedal digits, a fragmentary metacarpal, a right radius, one dorsal vertebra, one tail vertebra, and one manual digit.[1] Further fossil teeth hve been reported from north-Eastern Spain and attributed to Pyroraptor[2], however, a subsequent reevaluation concluded that these fossils probably belonged to some other dromeaosaurid species.[3]
A diagram of the dromaeosaurid dinosaur Pyroraptor olympius with selected fossil elements that can be reliably scaled using measurements given by Allain & Taquet (2000) to produce a realistic estimate of the taxon's size and proportions in life. This silhouette is based on the supposition of the missing elements of Pyroraptor's skeleton having fairly generalized dromaeosaurid proportions. By Mette Aumala - Own workSkeletal elements drawn based on Allain & Taquet (2000),"A new Genus of Dromaeosauridae (Dinosauria, Theropoda) from the Upper Cretaceous of France", Journal of Vertebrate Paleontology, 20: 404-407., CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=116444512
Valid species and taxonomy
The sole species belonging to the genus is Pyroraptor olympius . Due to the fragmentary state of Pyroraptor type material, there is a chance of synonymy between Pyroraptor and an other dromaeosaurid species, Variraptor, described from the same geological time and locality. However, as the type material of Variraptor is also fragmentary, and there is no overlap between the fossil material of the two taxa, more remains would be needed to test the theory of this synonymy.[4]
The precise classification of Pyroraptor is problematic, as due to its fragmentary remains, we do not know enough diadnostic characters of the species to make a good comparison with other dromaeosaurids. As a result of these reasons, Pyroraptor is often omitted from phylogenetic analyses.[5]
In two 2014 studies Pyroraptor was included into the phylogenetic tree of Microraptor[6], and also to the phylogenetic tree of Archeopteryx[7], causing a polytomy in the two cladograms. In the description of Hesperornithoides, in 2019, Pyroraptor was found to belong to unenlagiinae, which result was biostratigraphically and geographically consistent with the Cretaceous Europe.[8] This is in line with previous hypotheses suggesting that Pyroraptor and other Laurasian dromaeosaurids might have Gondwanan origins.[9][10] However, other researchers found that Pyroraptor did not fell within any Laurasian dromaeosaurid groups.[5] Furthermore, the description of Velociraptor greeni in 2022 elucidated some morphological traits which suggest that Pyroraptor might had more similar characteristics with unenlagiines, thereby supporting the idea of European raptors being closely related to groups in Africa and South America.[11] An other research from 2022, based on the sickle claw morphology, also found that Pyroraptor could be placed within unenlagiines.[12]
The serrated teeth of Pyroraptor makes more complicated its taxonomic position. Unenlagiines have no serrations on the edges of their teeth, and their teeth are usually fluted. This contradicts with the fact that the teeth of Pyroraptor does have serrated edges. This either means that Pyroraptor is a dromeaosaurid, and not an unenlagiid[13], or, that there existed exceptions within unenlagiids, with serrated and not fluted teeth.[3]
From evolutionary point of view, there is a chance that Pyroraptor and European dromaeosaurids were the remnants of those Late Jurassic or maybe Early Cretaceous paleofauna that evolved in its own separate way when Southern Europe was isolated during the late Cretaceous.[1] The other option is that these dinosaurs have Gondwanan origins, as their anatomy is more similar to Gondwanan Unenlagiines.[5][13]
Size comparison between the dinosaur Pyroraptor olympius and a human. Size of Pyroraptor is based on the holotype fossil. By Conty - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=12406682
Description
Pyroraptor was a small predatory theropod with a bird-like appearance. It had an enlarged and curved predatory claw on the second toe of each foot, which was about 6.5 centimeters long. We known only two teeth belonging to Pyroraptor, and these are flattened and curved backwards, and also have some serrations which is finer on the rear tooth margin than on the frontal edge.[1] Presumably, Pyroraptor had a similar built than other dromeaosaurids, e.g. probably it had a long and thin tail which helped in balancing, well-developed forelimbs which were armed with strong curved claws, an elongated head on a flexible and muscular neck, and the hindlegs being longer and more robust then the forelegs. Furthermore, likely its body was covered with feathers.
Paleobiology
The Argiles et Gres a Reptiles Formation, from which Pyroraptor was part of the Ibero-Arorican island landmass (today's Southern France and Northern Spain). Pyroraptor shared this place with a large number of other dinosaurs, such as Zalmoxes, Ampelosurus atacis, Arcovenator escotae, Tarascosaurus salluvicus, and Zalmoxes, and Lirainosaurus astibiae.[3]
Pyroraptor olimpius was a predatory dinosaur, which probably hunted for small amphibians, reptiles, like snakes or lizards, other small dinosaurs and mammals. The role of the enlarged curved claws on the hindlegs might be used during hunting. However, an other theory suggest, that it also could be used as climbing aid.[14] Unfortunately, due to the scarce and fragmentary fossil material of Pyroraptor , we do not know whether it lived in packs or it hunted alone.
Scientific references
[1] Allain, R., & Taquet, P. (2000): A new genus of Dromaeosauridae (Dinosauria, Theropoda) from the Upper Cretaceous of France. Journal of Vertebrate Paleontology, 20: 404-407.
[2] Pereda-Suberbiol, X.; Corral, J.C.; Astibia, H.; Badiola, A.; Bardet, N.; Berreteaga, A.; Buffetaut, E.; Buscalioni, A.D.; Cappetta, H.; Cavin, L.; Díez Díaz, V. (2015): Late cretaceous continental and marine vertebrate assemblages from the Lano quarry (Basque-Cantabrian Region, Iberian Peninsula): an update. Journal of Iberian Geology, 41 (1): 101-124. doi: 10.5209/rev_JIGE.2015.v41.n1.48658.
[3] Isasmendi, Erik; Torices, Angelica; Canudo, José Ignacio; Currie, Philip J.; Pereda-Suberbiola, Xabier (2022): Upper Cretaceous European theropod palaeobiodiversity, palaeobiogeography and the intra-Maastrichtian faunal turnover: new contributions from the Iberian fossil site of Lano. Papers in Palaeontology, 8 (1). doi: 10.1002/spp2.1419.
[4] Chanthasit, P.; Buffetaut, E. (2009): New data on the Dromaeosauridae (Dinosauria: Theropoda) from the Late Cretaceous of southern France. Bulletin de la Société Géologique de France, 180 (2): 145-154. doi: 10.2113/gssgfbull.180.2.145.
[5] Turner, A.H.; Makovicky, P.J.; Norell, M.A.(2018): A Review of Dromaeosaurid Systematics and Paravian Phylogeny. Bulletin of the American Museum of Natural Histor, 371: 1-206. doi: 10.1206/748.1.
[6] Pei, Rui; Li, Quanguo; Meng, Qingjin; Gao, Ke-Qin; Norell, Mark A. (2014): A New Specimen of Microraptor (Theropoda: Dromaeosauridae) from the Lower Cretaceous of Western Liaoning, China. American Museum Novitates, (3821): 1-28. doi: 10.1206/3821.1.
[7] Foth, C.; Tischlinger, H.; Rauhut, O.W.M. (2014): New specimen of Archaeopteryx provides insights into the evolution of pennaceous feathers. Nature, 511(7507): 79-82. doi: 10.1038/nature13467.
[8] Hartman, S.; Mortimer, M.; Wahl, W.R.; Lomax, D.R.; Lippincott, J.; Lovelace, D.M. (2019): A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7: e7247. doi: 10.7717/peerj.7247.
[9] Agnolín, Federico L.; Novas, Fernando E. (2013): Uncertain Averaptoran Theropods. Avian Ancestors, Dordrecht: Springer Netherlands, 37-47. doi: 10.1007/978-94-007-5637-3_4.
[10] Makovicky, P.J.; Apesteguía, S.; Agnolín, F.L. (2005): The earliest dromaeosaurid theropod from South America. Nature, 437 (7061): 1007-1011. doi: 10.1038/nature03996.
[11] Longrich, Nicholas R.; Martill, David M.; Jacobs, Megan L. (2022): A new dromaeosaurid dinosaur from the Wessex Formation (Lower Cretaceous, Barremian) of the Isle of Wight, and implications for European palaeobiogeography . Cretaceous Research, 134: 105123. doi: 10.1016/j.cretres.2021.105123.
[12] Santos Brilhante, Natan; de França, Tainá Constância; Castro, Fabiano; Sanches da Costa, Leandro; Currie, Philip J.; Kugland de Azevedo, Sergio Alex; Delcourt, Rafael (2022): A dromaeosaurid-like claw from the Upper Cretaceous of southern France. Historical Biology: 1-10. doi: 10.1080/08912963.2021.2007243.
[13] Brum, A.S.; Pegas, R.V.; Bandeira, K.L. N.; Souza, L.G.; Campos, D.A.; Kellner, A.W. A. (2021): A new unenlagiine (Theropoda, Dromaeosauridae) from the Upper Cretaceous of Brazil. Papers in Palaeontology, 7 (4): 2075-2099. doi: 10.1002/spp2.1375.
[14] Manning, P.L.; Payne, D.; Pennicott, J.; Barrett, P.M.; Ennos, R.A. (2005): Dinosaur killer claws or climbing crampons? Biology Letters 2; pp. 110-112. doi: 10.1098/rsbl.2005.0395.