Volkheimeria
Volkheimeria is an extinct genus of sauropod dinosaurs that lived in what is now Argentina during the Early Jurassic, 178–179 million years ago. Its type and only species is Volkheimeria chubutensis.
| Volkheimeria | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | †Sauropodomorpha |
| Clade: | †Sauropoda |
| Genus: | †Volkheimeria Bonaparte, 1979 |
| Species: | †V. chubutensis |
| Binomial name | |
| †Volkheimeria chubutensis Bonaparte, 1979 | |
Discovery and naming
The only known specimen of Volkheimeria was discovered at the site of Cerro Cóndor Sur, roughly a kilometer west of the village of Cerro Cóndor in Chubut Province, Argentina.[1] In 1979, José Bonaparte described it as representing a new genus and species, Volkheimeria chubutensis, alongside two other species discovered in the same strata, Piatnitzkysaurus floresi and Patagosaurus fariasi.[2] The genus name Volkheimeria honors the Argentinean paleontologist Wolfgang Volkheimer.[3]
Fossil record
Only a single specimen of Volkheimeria chubutensis is known: the holotype PVL 4077, a partial skeleton from the Cañadón Asfalto Formation of Argentina. This specimen consists of a partial cervical vertebra, two complete and two partial dorsal vertebrae, part of the sacrum, several incomplete caudal vertebrae, partial ilia, a pubis, an ischium, a femur, and a tibia.[1] The specimen was not fully grown, but had probably reached sexual maturity.[4] An isolated tooth found in the Cañadón Asfalto Formation, MPEF-PV 10860, may belong to Volkheimeria, though this cannot be proven without more complete specimens.[5]
Description
The size of a fully-grown Volkheimeria is not known, as it is only known from an immature specimen.[6]
Classification
Volkheimeria was originally identified as a primitive sauropod, distinguishable from Patagosaurus. Some phylogenetic analyses of the taxon have recovered it as a eusauropod, vulcanodontid, or primitive sauropod, though its position is variable due to its incomplete nature. The phylogenetic analysis of Pol and colleagues in 2022 recovered Volkheimeria as a non-eusauropod based on primitive features of the vertebrae, though alternative placements were identified as closer to either Amygdalodon or Archaeodontosaurus, as shown below.
| Sauropoda |
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Classification history
Bonaparte initially regarded Volkheimeria as a primitive member of Cetiosauridae.[2] He considered both it and Lapparentosaurus to represent an early stage in cetiosaurid evolution, more advanced than Vulcanodon but more primitive than Patagosaurus and Cetiosaurus.[7][8] In 1990, John S. McIntosh included both Volkheimeria and Lapparentosaurus in Brachiosauridae,[9] albeit without providing anatomical evidence for classifying Volkheimeria as such.[10] In 2004, Upchurch et al. regarded the affinities of Volkheimeria as uncertain, due to the lack of a phylogenetic analysis including the taxon.[10] In 2011, Pol et al. included both Volkheimeria and Lapparentosaurus in a phylogenetic analysis, and recovered them as basal eusauropods, more derived than Shunosaurus but more basal than Barapasaurus, with Volkheimeria more basal than Lapparentosaurus.[11] In 2017, Cerda et al. found Volkheimeria to be a non-eusauropod sauropod closely related to Tazoudasaurus.[4] In 2018, Holwerda and Pol found Volkheimeria to be a non-eusauropod sauropod, as the sister taxon of Spinophorosaurus.[12]
Evolution
Volkheimeria lived during the Toarcian age of the Early Jurassic, 178-179 million years ago.[1] The beginning of the Toarcian was a time of significant faunal turnover for sauropodomorphs, as all sauropodomorph lineages except for sauropods died out and eusauropods, which became the dominant sauropod group in the Middle Jurassic, began to diversify.[13] Volkheimeria was not a member of the eusauropod radiation, and was probably a representative of a lineage that diverged from other sauropods in the earliest Jurassic or even the Triassic.[1]
Paleoecology
The ecosystem represented by the Cañadón Asfalto Formation included at least four sauropods other than Volkheimeria chubutensis, all of them eusauropods: Bagualia alba,[13] Patagosaurus fariasi, an unnamed basal eusauropod,[14] and a possible neosauropod.[15]
References
- Pol, D.; Gomez, K.; Holwerda, F.H.; Rauhut, O.W.M.; Carballido, J.L. (2022). "Sauropods from the Early Jurassic of South America and the Radiation of Eusauropoda". In Otero, A.; Carballido, J.L.; Pol, D. (eds.). South American Sauropodomorph Dinosaurs. Record, Diversity and Evolution. Springer. pp. 131–163. doi:10.1007/978-3-030-95959-3. ISBN 978-3-030-95958-6. ISSN 2197-9596.
- Bonaparte, J.F. (1979). "Dinosaurs: A Jurassic Assemblage from Patagonia". Science. 205 (4413): 1377–1379. Bibcode:1979Sci...205.1377B. doi:10.1126/science.205.4413.1377. JSTOR 1748887. PMID 17732331. S2CID 34854458.
- Holtz, T. R. (2007). Dinosaurs: the most complete, up-to-date encyclopedia for dinosaur lovers of all ages. New York: Random House. ISBN 978-0-375-82419-7.
- Cerda, Ignacio Alejandro; Chinsamy, Anusuya; Pol, Diego; Apaldetti, Cecilia; Otero, Alejandro; Powell, Jaime Eduardo; Martínez, Ricardo Nestor (2017-06-27). "Novel insight into the origin of the growth dynamics of sauropod dinosaurs". PLoS ONE. 12 (6). doi:10.1371/journal.pone.0179707. ISSN 1932-6203.
- Becerra, Marcos G.; Gomez, Kevin L.; Pol, Diego (2017-10-19). "A sauropodomorph tooth increases the diversity of dental morphotypes in the Cañadón Asfalto Formation (Early – Middle Jurassic) of Patagonia". Comptes Rendus Palevol. 16 (8): 832–840. doi:10.1016/j.crpv.2017.08.005. ISSN 1631-0683.
- Paul, Gregory S. (2016). The Princeton Field Guide to Dinosaurs (2nd ed.). Princeton University Press.
- Bonaparte, J. F. (1986). "Les dinosaures (carnosaures, allosauridés, sauropodes, cétiosauridés) du Jurassique moyen de Cerro Cóndor (Chubut, Argentine)". Annales de Paléontologie. 72 (4): 325–386.
- Bonaparte, José F. (1986). "The early radiation and phylogenetic relationships of the Jurassic sauropod dinosaurs, based on vertebral anatomy". In Padian, Kevin (ed.). The beginning of the age of dinosaurs: faunal change across the Triassic–Jurassic boundary. Cambridge: Cambridge University Press. pp. 247–258. ISBN 0-521-30328-1.
- McIntosh, J. S. (1990). "Sauropoda". In Weishampel; Dodson, P.; Osmólska, H. (eds.). The Dinosauria (1 ed.). Berkeley: University of California Press. pp. 345–401.
- Upchurch, P.; Barrett, P. M.; Dodson, P. (2004). "Sauropoda". In Weishampel, D. B.; Dodson, P.; Osmólska, H. (eds.). The Dinosauria (2nd ed.). University of California Press.
- Pol, Diego; Garrido, Alberto; Cerda, Ignacio A. (2011-01-26). "A new sauropodomorph dinosaur from the Early Jurassic of Patagonia and the origin and evolution of the sauropod-type sacrum". PLoS ONE. 6 (1). doi:10.1371/journal.pone.0014572. ISSN 1932-6203.
- Holwerda, Femke M.; Pol, Diego (2018-12-13). "Phylogenetic analysis of Gondwanan basal eusauropods from the Early-Middle Jurassic of Patagonia, Argentina". Spanish Journal of Palaeontology. 33 (2): 289. doi:10.7203/sjp.33.2.13604. ISSN 2255-0550.
- Pol, D.; Ramezani, J.; Gomez, K.; Carballido, J. L.; Carabajal, A. Paulina; Rauhut, O. W. M.; Escapa, I. H.; Cúneo, N. R. (2020-11-25). "Extinction of herbivorous dinosaurs linked to Early Jurassic global warming event". Proceedings of the Royal Society B: Biological Sciences. 287 (1939). doi:10.1098/rspb.2020.2310. eISSN 1471-2954. ISSN 0962-8452.
- Holwerda, Femke M.; Pol, Diego; Rauhut, Oliver W. M. (2015-02-18). "Using Dental Enamel Wrinkling to Define Sauropod Tooth Morphotypes from the Cañadón Asfalto Formation, Patagonia, Argentina". PLoS ONE. 10 (2). doi:10.1371/journal.pone.0118100. ISSN 1932-6203.
- Carballido, José; Holwerda, Femke; Pol, Diego; Rauhut, Oliver (2017). "An Early Jurassic sauropod tooth from Patagonia (Cañadón Asfalto Formation): implications for sauropod diversity". Publicación Electrónica de la Asociación Paleontológica Argentina. 17 (2): 50–57. doi:10.5710/PEAPA.17.11.2017.249. ISSN 2469-0228.
