Tropeognathinae

Subfamily Tropeognathinae nov.

Zoobank LSID: urn:lsid:zoobank.org:act:0722EB2F­8A40­40E4­9896­E548202E54FE

Stem-based definition: The most inclusive clade containing Tropeognathus mesembrinus but not Coloborhynchus clavirostris or Anhanguera blittersdorffi .

Included genera: Ferrodraco Pentland, Poropat, Tischler, Sloan, Elliott, Elliott, and Elliott, 2019 , Mythunga Molnar and Thulborn, 2008 , Siroccopteryx Mader and Kellner, 1999 , and Tropeognathus Wellnhofer, 1987 .

Diagnosis.—Anhanguerids with reduced premaxillary/dentary lateral expansions (under 130% the width of the post­rosette width); relatively short teeth (crown height under 3 times diameter); and premaxillary crests reaching the rostral tip.

Remarks.— Tropeognathus mesembrinus is, alongside Anhanguera blittersdorffi , an internal specifier of a nodebased Anhangueridae sensu Kellner (2003) . In the present work, we recognize the Tropeognathinae as a clade joining Tropeognathus mesembrinus (Albian, Romualdo Formation, Brazil), Siroccopteryx moroccensis (Albian–Cenomanian, Kem Kem Group, Morocco), Ferrodraco lentoni (Winton Formation, Cenomanian–Turonian, Australia), and Mythunga camara (Albian, Toolebuc Formation, Australia). The relationships of Siroccopteryx moroccensis have been controversial (see Rodrigues and Kellner 2008; Holgado et al. 2019; Jacobs et al. 2019). Siroccopteryx has been previously regarded as a close relative of Coloborhynchus by several works ( Rodrigues and Kellner 2008, 2013; Andres et al. 2013, 2014; Holgado et al. 2019). Recently, anatomical comparisons between Siroccopteryx , Coloborhynchus , and Tropeognathus led Jacobs et al. (2019) to, very eloquently, reinterpret for the first time Siroccopteryx as a close relative of Tropeognathus instead of Coloborhynchus . The evidence presented by Jacobs et al. (2019) is taken into account here, leading us to support their conclusions (see further below on Phylogenetic Analysis and Discussion). The close relationship between Ferrodraco + Mythunga and Tropeognathus mesembrinus (see Pentland et al. 2019) is also corroborated here.

Concerning the phylogenetic relationships of Tropeognathus mesembrinus and previous analyses, under the works of Holgado et al. (2019) and Pêgas et al. (2019) Tropeognathus was recovered as a monotypic branch within the Anhangueridae , alongside the clades Coloborhynchinae and Anhanguerinae. Jacobs et al.(2019) recovered Tropeognathus mesembrinus as closely related to Ornithocheirus simus and Siroccopteryx moroccensis . Under the analyses of Andres et al. (2014) and Longrich et al. (2018), Tropeognathus mesembrinus was recovered as closely related to Ornithocheirus simus and Coloborhynchus clavirostris .

In the present work, we support a close relationship between Tropeognathus mesembrinus , Siroccopteryx moroccensis , Ferrodraco lentoni , and Mythunga camara , composing the Tropeognathinae (comprised within Anhangueridae ). However, this clade does not include Coloborhynchus clavirostris (or any other coloborhynchine) nor Ornithocheirus mesembrinus (regarded as a basal ornithocheiraean). Our systematic proposal and the synapomorphies behind it are further elaborated below.

Stratigraphic and geographic range.—Albian–Cenomanian– Turonian (probably Turonian); Romualdo Formation, Brazil; Toolebuc Formation, Australia; Kem Kem Group, Morocco; Winton Formation, Australia.