Bew pelvis of Gargantuavis (1 Viewer)

Gerald Mayr, Vlad Codrea, Alexandru Solomon, Marian Bordeianu & Thierry Smith, 2019

A well-preserved pelvis from the Maastrichtian of Romania suggests that the enigmatic Gargantuavis is neither an ornithurine bird nor an insular endemic

Cretaceous Research. in press: Article 104271. doi:10.1016/j.cretres.2019.104271

https://www.sciencedirect.com/science/article/pii/S0195667119302289?via=ihub

Highlights

first record of Gargantuavis outside the Ibero-Armorican Island.

new biogeographic link between the Hațeg and Ibero-Armorican islands.

disproval of ornithurine affinities of Gargantuavis.

new fossil that may elucidate the affinities of previously described birds from Romania.

Abstract

We describe a well-preserved pelvis from the Maastrichtian Sânpetru Formation of the Haţeg Basin in Romania. The fossil closely resembles the pelvis of Gargantuavis philoinos from the Ibero-Armorican Peninsula, but differs in a smaller size and a few morphological features. It constitutes the first record of Gargantuavis outside the Ibero-Armorican Island and is more complete than any of the previously known Gargantuavis pelves. The new fossil allows the recognition of characteristics previously unknown for Gargantuavis. These include the presence of large supratrochanteric processes, the absence of a widened midsection of the synsacrum (which indicates the absence of a glycogen body), and the absence of fusion between the pelvic bones at the level of the acetabulum. The latter two features suggest that Gargantuavis is not closely related to the Ornithurae and the taxon may even fall outside the Ornithothoraces, the clade including Enantiornithes and Ornithuromorpha. Recognition of Gargantuavis in the fauna of the Haţeg Island is of particular significance, because various theropods have been described from the Upper Cretaceous of Romania. The Romanian pelvis is of similar-size to Elopteryx nopcsai, which was described as avian and is based on hindlimb elements, and it also shows some similarities to the pelvis of the unusual theropod Balaur bondoc. The new fossil furthermore disproves the hypothesis that the flight capabilities of I]Gargantuavis[/I] were lost in an insular environment of the Ibero-Armorican Island, and raises the possibility that Gargantuavis, Elopteryx, and Balaur belong to a distinctive theropod clade of the Late Cretaceous European archipelago.

Enjoy,

Fred

Eric Buffetaut & Delphine Angst, 2020

Gargantuavis is an insular basal ornithurine: a comment on Mayr et al., 2020, 'A well-preserved pelvis from the Maastrichtian of Romania suggests that the enigmatic Gargantuavis is neither an ornithurine bird nor an insular endemic'

Cretaceous Research. in press: Article 104438. doi:10.1016/j.cretres.2020.104438

Abstract: https://www.sciencedirect.com/science/article/pii/S0195667120300124?via=ihub

We agree with Mayr et al., 2020, that a pelvis from the Maastrichtian of Romania closely resembles Garantuavis philoinos, from the Late Cretaceous of the Ibero-Armorican island, showing that gargantuaviids were not restricted to the latter landmass. However, we disagree with many other assertions and interpretations of Mayr et al.: contrary to their claims, lines of arrested growth are known in the bones of many modern birds; not all terrestrial birds have a narrow pelvis; the pubic and ischiadic peduncles are broken on all Gargantuavis pelves from the Ibero-Armorican island; an enlargement of the middle part of the synsacrum (to accomodate the glycogen body) is not present in all Ornithothoraces, since it is absent in Hesperornithiformes (probably because of the low number of preacetabular synsacral vertebrae, as in Gargantuavis); the palaeobiogeographical scenario proposed by Mayr et al. is not supported by palaeogeographical reconstructions of Cretaceous Europe. We conclude that Gargantuavis was a basal ornithurine, at an evolutionay level similar to that of Hesperornithiformes, in all likelihood the result of insular evolution (involving the crossing of sea barriers) on the Late Cretaceous European archipelago.

Fred

Gerald Mayr, Vlad Codrea, Alexandru Solomon, Marian Bordeianu & Thierry Smith, 2020

Reply to comments on "A well-preserved pelvis from the Maastrichtian of Romania suggests that the enigmatic Gargantuavis is neither an ornithurine bird nor an insular endemic

Cretaceous Research. in press: Article 104465. doi:10.1016/j.cretres.2020.104465

Abstract: https://www.sciencedirect.com/science/article/pii/S0195667120300872?via=ihub

We appreciate the comments of Buffetaut and Angst on our recent study of a Gargantuavis-like pelvis from the Late Cretaceous of Romania. We consider some of their points to be valid, but maintain our conclusion on the likely absence of a glycogen body in Gargantuavis and the lack of fusion of the pelvic elements in the acetabular region. Both characters conflict with a classification of the taxon into Ornithurae. We also uphold our hypothesis that Gargantuavis is possibly related to the enigmatic theropod Balaur bondoc.

Fred