Geosaurinae Bonaparte 1845
Creators: name: Young, Mark T.
name: Wilberg, Eric W.
name: Johnson, Michela M.
name: Herrera, Yanina
name: Brandalise, Marco de Andrade
name: Brignon, Arnaud
name: Sachs, Sven
name: Abel, Pascal
name: Foffa, Davide
name: Fernández, Marta S.
name: Vignaud, Patrick
name: Cowgill, Thomas
name: Brusatte, Stephen L.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Crocodylia
Metriorhynchidae

description: Geosaurinae Bonaparte, 1845 (Zoological Code)
Geosaurinae Bonaparte 1845: 4, (as Geosaurina), converted clade name (PhyloCode)
RegNum registration number 1020.
Type genus: Geosaurus Cuvier, 1824.
Etymology
‘Pertaining to Geosaurus ’. The stem Geosaur - is based on the genus Geosaurus. - inae, is a Latin feminine plural suffix for ‘pertaining to’. Under Article 29.2 of the Zoological Code, the suffix - inae denotes a subfamily rank within the family-group.
Geological range
Middle Jurassic (early Bathonian) to Early Cretaceous (earliest Aptian) (Cau and Fanti 2011, Chiarenza et al. 2015, Sachs et al. 2020).
PhyloCode phylogenetic definition
The largest clade within Metriorhynchidae containing Geosaurus giganteus (von Sömmerring 1816) but not Rhacheosaurus gracilis von Meyer, 1831, Metriorhynchus brevirostris (Holl 1829), and Gracilineustes leedsi (Andrews 1913).
Reference phylogeny
Fig. 3.
Zoological Code diagnosis and PhyloCode diagnostic apomorphies
Metriorhynchid crocodylomorphs with the following unique combination of characters (6): cranial rostrum with a mesorostrine condition created by elongation of the maxilla (shared with ‘ Cricosaurus ’ saltillensis) (7.1); cranial rostrum wider than high (8.0); anterior margin of the choana is ‘M’-shaped (shared with Maledictosuchus) (379.2); paroccipital process largely horizontal, with the lateral ends sharply inclined (415.2); surangular along the dorsal margin of the mandible does not extend anteriorly beyond the orbits (545.0); 20 or fewer maxillary alveoli (within Metriorhynchidae, shared with the Cretaceous rhacheosaurin) (594.1–3).
Potentially diagnostic characters
Depending on the phylogenetic position of the South American ‘ Metriorhynchus ’ species, the dentition having true denticles (653.1–2) could be diagnostic for Geosaurinae or a more inclusive subclade. The posterior cervical vertebral centra being subequal in length and width (699.1) may be diagnostic to Geosaurinae, within Metriorhynchidae this character is only known amongst geosaurines.
Composition
Neptunidraco, the subclade Geosaurini, and multiple taxa that do not have a valid generic assignment (e.g. ‘ Metriorhynchus ’ brachyrhynchus, the ‘E’-clade, and the indeterminate specimens in Plesiosuchina and Dakosaurina).
Comments
Authorship: The nomen Geosaurinae was first used by Bonaparte (1845: 4), as Geosaurina, not Lydekker (1888a) as reported by Young and Andrade (2009).
Prior phylogenetic definition: Young and Andrade (2009) defined Geosaurinae as the most inclusive clade, including Geosaurus giganteus (von Sömmerring 1816), but not Metriorhynchus geoffroyii von Meyer, 1832. Here we have added Rhacheosaurus gracilis and Gracilineustes leedsi as external specifiers, as they are now internal specifiers for Metriorhynchinae.
description: Published as part of Young, Mark T., Wilberg, Eric W., Johnson, Michela M., Herrera, Yanina, Brandalise, Marco de Andrade, Brignon, Arnaud, Sachs, Sven, Abel, Pascal, Foffa, Davide, Fernández, Marta S., Vignaud, Patrick, Cowgill, Thomas & Brusatte, Stephen L., 2024, The history, systematics, and nomenclature of Thalattosuchia (Archosauria: Crocodylomorpha), pp. 547-617 in Zoological Journal of the Linnean Society 200 (2) on page 606, DOI: 10.1093/zoolinnean/zlad165, http://zenodo.org/record/11241243