Thalassodrominae

Thalassodrominae or Thalassodromidae (meaning "sea runners", due to previous misconceptions of skimming behavior; they are now thought to be terrestrial predators) is a group of azhdarchoid pterosaurs from the Cretaceous period. Its traditional members come from Brazil, however, other possible members also come from other places, including Morocco and Argentina. Thalassodrominae is considered either to be a subfamily within the pterosaur family Tapejaridae, or as a distinct family, Thalassodromidae, within the clade Neoazhdarchia, closely related to dsungaripterids or azhdarchids.

Thalassodromines Temporal range: Early-Late Cretaceous, 112–88 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Replica skeleton of Tupuxuara leonardii
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Order:	†Pterosauria
Suborder:	†Pterodactyloidea
Clade:	†Tapejaromorpha
Subfamily:	†Thalassodrominae Kellner, 2007
Type species
†Thalassodromeus sethi Kellner & Campos, 2002
Genera
†Aerotitan? †Alanqa? †Argentinadraco? †Banguela? †Kariridraco †Lacusovagus? †Leptostomia? †Thalassodromeus †Tupuxuara †Xericeps?
Synonyms
Tupuxuaridae Martill, Bechly & Heads, 2007 Thalassodromidae Witton, 2009

Classification

Thalassodrominae traditionally includes only two genera, Thalassodromeus and Tupuxuara, and was defined to include them and any other descendants of their most recent common ancestor.^[1] The classification of thalassodromines is controversial. Some studies, including one by Lü and colleagues in 2008, have found that the thalassodromines are more closely related to the azhdarchids than to the tapejarids,^[2] and have placed them in their own family (which has sometimes been referred to as Tupuxuaridae,^[3] though Thalassodrominae was named first^[1]). Alternately, they have been considered a family within the clade Neoazhdarchia, as Thalassodromidae.^[4]

Below are three alternate cladograms resulting from studies of azhdarchoid relationships. The first, presented by Felipe Pinheiro and colleagues in 2011, found the thalassodromines as a subgroup within the Tapejaridae.^[5] The second, presented by Lü and colleagues in 2008, found them to be closer to the Azhdarchidae, though they used the name Tupuxuaridae for the group.^[2] The third, presented by Brian Andres, James Clark and Xu Xing in 2014, also found thalassodromines closer to azhdarchids, and as the sister group of the dsungaripterids.^[6]

Azhdarchoidea	Azhdarchidae Tapejaridae Thalassodrominae Chaoyangopterinae Tapejarinae

Azhdarchoidea	Tapejaridae Neoazhdarchia Tupuxuaridae Chaoyangopteridae Azhdarchidae

Azhdarchoidea	Tapejaromorpha Neoazhdarchia Thalassodrominae Dsungaripteridae Chaoyangopteridae Azhdarchidae

More recently, the Late Cretaceous genera Alanqa and Aerotitan, typically considered azhdarchids, have been recovered as thalassodromines (the group is defined as Thalassodromidae in the study). However, their remains are fragmentary, so this assignment is only tentative,^[7] and a 2021 study further show dissimilarities between them and azhdarchids, with Aerotitan being a true azhdarchid while Alanqa was a basal azhdarchoid related to Keresdrakon.^[8]

References

1. Kellner, A.W.A.; Campos, D.A. (2007). "Short note on the ingroup relationships of the Tapejaridae (Pterosauria, Pterodactyloidea". Boletim do Museu Nacional. 75: 1–14.
2. Lü, J., Unwin, D.M., Xu, L., and Zhang, X. (2008). "A new azhdarchoid pterosaur from the Lower Cretaceous of China and its implications for pterosaur phylogeny and evolution." Naturwissenschaften,
3. Martill, D.M., Bechly, G., and Heads, S.W. (2007). "Appendix: species list for the Crato Formation." In: Martill, D.M., Bechly, G., and Loveridge, R.F. (eds.), 2007. The Crato Fossil Beds of Brazil: Window into an Ancient World. Cambridge University Press, Cambridge. Pp. 582–607.
4. Witton, M. P. (2009). "A new species of Tupuxuara (Thalassodromidae, Azhdarchoidea) from the Lower Cretaceous Santana Formation of Brazil, with a note on the nomenclature of Thalassodromidae". Cretaceous Research. 30 (5): 1293–1300. Bibcode:2009CrRes..30.1293W. doi:10.1016/j.cretres.2009.07.006. S2CID 140174098.
5. Pinheiro, F.L., Fortier, D.C., Schultz, C.L., De Andrade, J.A.F.G. and Bantim, R.A.M. (in press). "New information on Tupandactylus imperator, with comments on the relationships of Tapejaridae (Pterosauria)." Acta Palaeontologica Polonica, in press, available online 03 Jan 2011. doi:10.4202/app.2010.0057
6. Andres, B.; Clark, J.; Xu, X. (2014). "The Earliest Pterodactyloid and the Origin of the Group". Current Biology. 24 (9): 1011–6. Bibcode:2014CBio...24.1011A. doi:10.1016/j.cub.2014.03.030. PMID 24768054.
7. Longrich, N.R., Martill, D.M., and Andres, B. (2018). Late Maastrichtian pterosaurs from North Africa and mass extinction of Pterosauria at the Cretaceous-Paleogene boundary. PLoS Biology, 16(3): e2001663. doi:10.1371/journal.pbio.2001663
8. Pêgas, R.V.; Holgado, B.; Ortiz David, L.D.; Baiano, M.A.; Costa, F.R. (August 21, 2021). "On the pterosaur Aerotitan sudamericanus (Neuquén Basin, Upper Cretaceous of Argentina), with comments on azhdarchoid phylogeny and jaw anatomy". Cretaceous Research. 129: Article 104998. doi:10.1016/j.cretres.2021.104998. ISSN 0195-6671. S2CID 238725853.