Glyptosaurinae

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Lepidosauromorpha
Superordo: Lepidosauria
Ordo: Squamata
Cladus: Unidentata, Episquamata
Cladus: Toxicofera
Subordo: Anguimorpha
Infraordo: Neoanguimorpha
Superfamilia: Diploglossa

Familia: Anguidae
Subfamilia: †Glyptosaurinae
Genera: Glyptosaurus - Helodermoides - Odaxosaurus - Paraglyptosaurus - Paraplacosauriops - Placosaurus - Proglyptosaurus - Proxestops

Name

Glyptosaurinae Marsh 1872
Vernacular names
English: Glyptosaurine lizards

Glyptosaurinae is an extinct subfamily of anguid lizards that lived in the Northern Hemisphere during the Late Cretaceous and the Paleogene.
Description
Skull of the glyptosaurine Peltosaurus

Glyptosaurines are known primarily from their osteoderms, scale-like pieces of bone that are embedded in the skin and cover much of their bodies. The shape and extent of the osteoderms in glyptosaurines are similar to those seen in an unrelated group of lizards called Monstersauria, which includes the living Gila monster and beaded lizard.[1] The osteoderms of glyptosaurines are unusually complex, consisting of four distinct layers of bony tissue. These tissues may have derived from both the dermis (the lower layer of the skin) and the epidermis (the outer layer of the skin) during their development in the embryo. The tissue forming the outermost layer of glyptosaurine osteoderms is similar to tooth enamel and has even been given its own name, osteodermine.[2]

Glyptosaurines have been split into the subgroups Melanosaurini and Glyptosaurini, although recent phylogenetic analyses show that Melanosaurini in its traditional sense is paraphyletic, representing an evolutionary grade of glytosaurines more basal ("primitive") than Glyptosaurini. Below is a cladogram from Conrad and Norell (2008) showing the interrelationships of glyptosaurines and their relationship to other anguid lizards:[1]

Anguimorpha

†Carusioidea Anguidae Diploglossinae †Glyptosaurinae †Odaxosaurus piger †Proxestops jepseni †Xestops vagans †Paraplacosauriops quercyi †Peltosaurus granulosus †Melanosaurini (sensu stricto) †Arpadosaurus gazinorum †Melanosaurus maximus †Glyptosaurini †Glyptosaurus sylvestris †Placosaurus rugosus †Proglyptosaurus huerfanensis †Paraglyptosaurus princeps †Helodermoides tuberculatus †Placosaurus estesi †Stenoplacosaurus mongoliensis Anguinae Gerrhonotinae

Evolutionary history

The earliest known Glyptosaurines like Odaxosaurus are known from the Late Cretaceous (Campanian) of North America. They arrived in Europe at the beginning of the Eocene (Ypresian). Only a single species, Stenoplacosaurus mongoliensis dating to the Mid-Eocene, is known from Asia. Glyptosaurines declined after the Mid-Eocene, become extinct in Europe by the end of the period as part of the "Grande Coupure".[3] The youngest known remains of glyptosaurines is Peltosaurus granulosus from the Monroe Creek and upper Sharps formations of Sharps Corner, South Dakota, dating to the mid Oligocene, between 27.4 and 26.4 million years ago.[4]
References

Conrad, J. L.; Norell, M. A. (2008). "The braincases of two glyptosaurines (anguidae, Squamata) and anguid phylogeny". American Museum Novitates (3613): 1. doi:10.1206/586.1. hdl:2246/5917. S2CID 55155105.
De Buffrénil, V.; Dauphin, Y.; Rage, J. C.; Sire, J. Y. (2011). "An enamel-like tissue, osteodermine, on the osteoderms of a fossil anguid (Glyptosaurinae) lizard". Comptes Rendus Palevol. 10 (5–6): 427. doi:10.1016/j.crpv.2011.03.010.
Sullivan, Robert M. (2019-10-01). "The taxonomy, chronostratigraphy and paleobiogeography of glyptosaurine lizards (Glyptosaurinae, Anguidae)". Comptes Rendus Palevol. 18 (7): 747–763. doi:10.1016/j.crpv.2019.05.006. ISSN 1631-0683. S2CID 202174449.
Scarpetta, Simon G. (2019-05-04). "Peltosaurus granulosus (Squamata, Anguidae) from the middle Oligocene of Sharps Corner, South Dakota, and the youngest known chronostratigraphic occurrence of Glyptosaurinae". Journal of Vertebrate Paleontology. 39 (3): e1622129. doi:10.1080/02724634.2019.1622129. ISSN 0272-4634. S2CID 196690362.