Janenschia

Discovery and naming

In 1911, Richard Sternfeld renamed Gigantosaurus Fraas 1908 to Tornieria, pointing out that Fraas's arguments had been irrelevant. Tornieria africana became the type species of the new genus. G. robustus was placed in Tornieria, as T. robusta. Sternfeld's move was not well received in Germany, as he had acted without consent of the ailing Fraas. In a 1922 article describing the hand of the animal, Werner Janensch, who at the Tendaguru had collected additional material, announced that he would keep using the name Gigantosaurus robustus. He claimed that G. megalonyx was a forgotten nomen oblitum and that the rules of the zoological nomenclature should be disregarded if they caused instability by replacing a well-known name by a completely new one. At the same time he synonymized Tornieria with Barosaurus as regarded its type species which then became a Barosaurus africanus. Janensch, for the remainder of his career, would consistently apply the name Gigantosaurus robustus. In 1928, Sidney Henry Haughton exceptionally assigned Tornieria robusta to Barosaurus also, as a Barosaurus robustus.

In 1930, Baron Franz Nopcsa rejected Janensch's arguments. He admitted that Sternfeld had been discourteous but pointed out that the ICZN only in 1927 recommended that the original author should be involved in such name changes. It would thus be absurd to object to an article written in 1911 — and in any case the lack of courtesy had no bearing on the validity of the name. Nopcsa had found several later mentions of G. megalonyx, which thus had not been a nomen oblitum. Furthermore, Gigantosaurus robustus had not exactly been a well-known name itself, prior to 1922. Distasteful as it might be, Nopcsa concluded, it was inevitable to consider Tornieria to be a valid name. SMNS 12144 was subsequently referred to Tornieria by other authors.

In 1991, German palaeontologist Rupert Wild of the Stuttgart Museum of Natural Sciences clarified the taxonomic status of G. robustus by concluding that it was generically distinct from Tornieria. He renamed it Janenschia in honor of Werner Janensch, who had studied the vertebrate fauna from Tendaguru. Janenschia was placed in the family Titanosauridae, making it the oldest member of Titanosauria.

A number of specimens formerly assigned to Janenschia have been recognized as distinct genera. Two anterior dorsal vertebrae, and a possible posterior cervical vertebra, previously referred to the genus, were named Tendaguria in 2000. On the other hand, the caudal vertebral series MB.R.2091.1–30 does not overlap with SMNS 12144 and instead represents the first taxon of Mamenchisauridae from outside Asia, Wamweracaudia.{{cite journal |doi=10.1111/zoj.12029 |title=Osteology of the Late Jurassic Portuguese sauropod dinosaur Lusotitan atalaiensis (Macronaria) and the evolutionary history of basal titanosauriforms |journal=Zoological Journal of the Linnean Society |volume=168 |pages=98–206 |year=2013 |last1=Mannion |first1=Philip D. |last2=Upchurch |first2=Paul |last3=Barnes |first3=Rosie N. |last4=Mateus |first4=Octávio

References

References

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8. Janensch, W., 1922, "Das Handskelett von ''Gigantosaurus robustus'' und ''Brachiosaurus brancai'' aus den Tendaguru-Schichten Deutsch-Ostafrikas", ''Centralblatt für Mineralogie, Geologie und Paläontologie'' '''1922''': 464–480
9. (1928). "On some reptilian remains from the Dinosaur Beds of Nyasaland". Transactions of the Royal Society of South Africa.
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15. Wild, R. (1991). Janenschia n. g. robusta (E. Fraas 1908) pro Tornieria robusta (E. Fraas 1908) (Reptilia, Saurischia, Sauropodomorpha) [Janenschia n. g. robusta (E. Fraas 1908) for Tornieria robusta (E. Fraas 1908) (Reptilia, Saurischia, Sauropodomorpha)]. Stuttgarter Beiträge zur Naturkunde, Serie B (Geologie und Paläontologie) 173:1–4
16. (September 2024). "Review of Janenschia Wild, with the description of a new sauropod from the Tendaguru beds of Tanzania and a discussion on the systematic value of procoelous caudal vertebrae in the Sauropoda". Palaeontographica Abteilung A.
17. (2019). "Taxonomic affinities of the putative titanosaurs from the Late Jurassic Tendaguru Formation of Tanzania: phylogenetic and biogeographic implications for eusauropod dinosaur evolution". Zoological Journal of the Linnean Society.
18. (2015). "The Anatomy and Phylogenetic Relationships of ''"Pelorosaurus" becklesii'' (Neosauropoda, Macronaria) from the Early Cretaceous of England". PLOS ONE.