Biology:Koleken

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Koleken (meaning "coming from clay and water") is a genus of carnotaurin abelisaurid from the Maastrichtian La Colonia Formation in the Chubut Province of Argentina. The genus contains a single species, Koleken inakayali, known from one immature specimen about 4.97 metres (16.3 ft) long and six years old in minimum age.[1][2]

Discovery and naming

Koleken is known from only the holotype MPEF-PV 10826 which was initially found and reported in 2015,[3] but was not described as K. inakayali until 2024. The holotype consists of "closely associated (but disarticulated) remains of the skull and atlas, as well as the articulated postcranial skeleton composed of the posteriormost eight dorsal vertebrae, a complete sacrum, eight caudal vertebrae, an almost complete pelvis and hind limbs". It differs from the larger Carnotaurus in anatomical characteristics found in the skull, vertebrae, and leg bones. The specimen is likewise believed to represent a sub-adult based on a lack of fusion in some of the bones.[1]

The generic name, Koleken, is a name in Teushen spoken by the native population of central Patagonia that means "coming from clay and water", given the specimen was found in a sedimentary section dominated by claystone representing an estuarine environment. The specific name, inakayali, honours Inakayal, one of the last chiefs of Tehuelches, native people from central Patagonia.[1]

Classification

Speculative life restoration

Koleken is placed in the Carnotaurini tribe of Abelisauridae, in a polytomy with the other carnotaurins in a phylogenetic analysis:[1]

Abelisauridae

Xenotarsosaurus

Eoabelisaurus

Spectrovenator

Rugops

"Majungasaurinae"

Brachyrostra

Arcovenator

Ekrixinatosaurus

Ilokelesia

Skorpiovenator

Furileusauria

Llukalkan

Viavenator

Carnotaurini

Koleken

Niebla

Carnotaurus

Aucasaurus

Paleoenvironment

Koleken was found in outcrops of the La Colonia Formation, which dates to the Maastrichtian (Cretaceous)–Paleocene (Paleogene) boundary.[4] This formation is best known for fossils of the abelisaurid theropod Carnotaurus and the saltasauroid titanosaur Titanomachya,[1][5] as well as fossils of other reptiles including the turtle Patagoniaemys, the snake Alamitophis and the plesiosaurs Kawanectes, Chubutinectes and Sulcusuchus.[3][6][7][8] Mammals discovered from the formation include Reigitherium, Coloniatherium, Argentodites and Ferugliotherium.[9][10] Remains of an enantiornithine and, possibly, of a neornithine bird have been discovered.[11][12]

References

  1. 1.0 1.1 1.2 1.3 1.4 Pol, Diego; Baiano, Mattia Antonio; Černý, David; Novas, Fernando; Cerda, Ignacio A.; Pittman, Michael (21 May 2024). "A new abelisaurid dinosaur from the end Cretaceous of Patagonia and evolutionary rates among the Ceratosauria". Cladistics 40 (3): 307–356. doi:10.1111/cla.12583. PMID 38771085. 
  2. Seculi Pereyra, E. E.; Pérez, D. E.; Méndez, A. H. (2025). "Macroevolutionary trends in Ceratosauria body size: insights of phylogenetic comparative methods". BMC Ecology and Evolution 25 (1): 32. doi:10.1186/s12862-025-02374-y. PMID 40221646. Bibcode2025BMCEE..25...32P.  Refer Table 2, Supplementary data 1
  3. 3.0 3.1 Gasparini, Zulma; Sterli, Juliana; Parras, Ana; Patricio O'Gorman, José; Salgado, Leonardo; Varela, Julio; Pol, Diego (May 2015). "Late Cretaceous reptilian biota of the La Colonia Formation, central Patagonia, Argentina: Occurrences, preservation and paleoenvironments". Cretaceous Research 54: 154–168. doi:10.1016/j.cretres.2014.11.010. Bibcode2015CrRes..54..154G. https://www.sciencedirect.com/science/article/abs/pii/S0195667114002225. Retrieved 21 May 2024. 
  4. Clyde, W. C.; Krause, J. M.; De Benedetti, F.; Ramezani, J.; Cúneo, N. R.; Gandolfo, M. A.; Haber, P.; Whelan, C. et al. (2021-10-01). "New South American record of the Cretaceous–Paleogene boundary interval (La Colonia Formation, Patagonia, Argentina)". Cretaceous Research 126. doi:10.1016/j.cretres.2021.104889. ISSN 0195-6671. Bibcode2021CrRes.12604889C. 
  5. Pérez-Moreno, A.; Salgado, L.; Carballido, J. L.; Otero, A.; Pol, D. (2024). "A new titanosaur from the La Colonia Formation (Campanian-Maastrichtian), Chubut Province, Argentina". Historical Biology: An International Journal of Paleobiology 37 (4): 792–811. doi:10.1080/08912963.2024.2332997. 
  6. O'Gorman, José P.; Carignano, Ana Paula; Calvo-Marcilese, Lydia; Pérez Panera, Juan Pablo (2023-08-10). "A new elasmosaurid (Sauropterygia, Plesiosauria) from the upper levels of the La Colonia Formation (upper Maastrichtian), Chubut Province, Argentina" (in en). Cretaceous Research 152. doi:10.1016/j.cretres.2023.105674. ISSN 0195-6671. Bibcode2023CrRes.15205674O. https://www.sciencedirect.com/science/article/pii/S0195667123002021. 
  7. José Patricio O'Gorman (2020). "First record of Kawanectes lafquenianum (Plesiosauria, Elasmosauridae) from the La Colonia Formation of Argentina, with comments on the mandibular morphology of elasmosaurids". Alcheringa: An Australasian Journal of Palaeontology 44 (1): 176–193. doi:10.1080/03115518.2019.1687754. Bibcode2020Alch...44..176P. 
  8. O'Gorman, J.P.; Gasparini, Z. (2013). "Revision of Sulcusuchus erraini (Sauropterygia, Polycotylidae) from the Upper Cretaceous of Patagonia, Argentina". Alcheringa: An Australasian Journal of Palaeontology 37 (2): 163–176. doi:10.1080/03115518.2013.736788. Bibcode2013Alch...37..163O. 
  9. Forasiepi, Analía M.; Coria, Rodolfo A.; Hurum, Jørn; Currie, Philip J. (1 December 2012). "First Dryolestoid (Mammalia, Dryolestoidea, Meridiolestida) from the Coniacian of Patagonia and New Evidence on their Early Radiation in South America". Ameghiniana 49 (4): 497. doi:10.5710/AMGH.8.8.2012.581. Bibcode2012Amegh..49..497F. 
  10. Gurovich, Y.; Beck, R. (2009). "The phylogenetic affinities of the enigmatic mammalian clade Gondwanatheria". Journal of Mammalian Evolution 16 (1): 25–49. doi:10.1007/s10914-008-9097-3. 
  11. Lawver, Daniel R.; Debee, Aj M.; Clarke, Julia A.; Rougier, Guillermo W. (January 1, 2011). "A New Enantiornithine Bird from the Upper Cretaceous La Colonia Formation of Patagonia, Argentina". Annals of Carnegie Museum 80 (1): 35–42. doi:10.2992/007.080.0104. Bibcode2011AnCM...80...35L. 
  12. Acosta Hospitaleche, C.; O'Gorman, J. P.; Panzeri, K. M. (2023). "A new Cretaceous bird from the Maastrichtian La Colonia Formation (Patagonia, Argentina)". Cretaceous Research 150: 105595. doi:10.1016/j.cretres.2023.105595. Bibcode2023CrRes.15005595A. 

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Wikidata ☰ Q126012874 entry