''Fylax'' (meaning "keeper") is a genus of

hadrosauroid Hadrosauroidea is a clade or superfamily of ornithischian dinosaurs that includes the "duck-billed" dinosaurs, or hadrosaurids, and all dinosaurs more closely related to them than to ''Iguanodon''. Their remains have been recovered in Asia, Eu ...

ornithopod Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (), that started out as small, bipedal running grazers and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous wo ...

from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

Figuerola Formation of

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

. The genus contains a single species, ''Fylax thyrakolasus'', known from a nearly complete left dentary.

Discovery and naming

The holotype of ''Fylax'', IPS-36338, a left dentary, was discovered in the early 1990s. It was found in the Figuerola Formation in

Lleida province The Province of Lleida (; Aranese Occitan: Lhèida ; es, Lérida ) is one of the four provinces of Catalonia. It lies in north-eastern Spain, in the western part of the autonomous community of Catalonia, and is bordered by the Provinces of ...

, northeastern Spain. It was initially described in 1999.Casanovas, M.L., Pereda Suberbiola, X.P., Santafé, J.V., and Weishampel, D.B. 1999. "A primitive euhadrosaurian dinosaur from the uppermost Cretaceous of the Ager syncline (southern Pyrenees, Catalonia)". ''Geologie en Mijnbouw'' 78: 345–356 In 2021, Albert Prieto-Márquez and Miguel Ángel Carrera Farias described the dentary as belonging to a new genus of hadrosauroid dinosaur. The generic name, ''Fylax,'' comes from the modern Greek, fýlax (keeper), and the specific name, ''thyrakolasus'', comes from the Greek thýra (gate) and kólasi (hell), thus creating the combination "keeper of the gates of hell” in reference to the proximity of this taxon to the Cretaceous-Paleogene mass extinction event.

Classification

Prieto-Márquez and Carrera Farias recover ''Fylax'' as the sister taxon to ''

Tethyshadros ''Tethyshadros'' ("Tethys Ocean, Tethyan hadrosauroid") is a genus of hadrosauroidea, hadrosauroid dinosaur from Trieste, Italy. The type and only species is ''T. insularis''. Discovery and naming Sometime in the 1980s, Alceo Tarlao and Giorgi ...

'', in a derived position in the

Hadrosauromorpha Hadrosauromorpha is a clade of iguanodontian ornithopods, defined in 2014 by David B. Norman to divide Hadrosauroidea into the basal taxa with compressed manual bones and a pollex, and the derived taxa that lack them. The clade is defined as ...

, making it one of the latest surviving non-hadrosaurid hadrosauromorphs. Their cladogram is shown below:

References

{{Taxonbar, from=Q107088395 Hadrosaurs Fossils of Spain Cretaceous Spain Fossil taxa described in 2021 Ornithischian genera