''Proa'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of basal

styracosterna Ankylopollexia is an extinct clade of ornithischian dinosaurs that lived from the Late Jurassic to the Late Cretaceous. It is a derived clade of iguanodontian ornithopods and contains the subgroup Styracosterna. The name stems from the Greek wo ...

n iguanodont known from the

Early Cretaceous The Early Cretaceous (geochronological name) or the Lower Cretaceous ( chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pr ...

Escucha Formation The Escucha Formation is a geological formation in La Rioja and Teruel provinces of northeastern Spain whose strata date back to the late Aptian to middle Albian stages of the Early Cretaceous. Dinosaur remains are among the fossils that have bee ...

(lower

Albian The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/ Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± ...

stage) of

Teruel Province Teruel (Catalan: ''Terol'' ) is a province of Aragon, in the northeast of Spain. The capital is Teruel. It is bordered by the provinces of Tarragona, Castellón, Valencia (including its exclave Rincón de Ademuz), Cuenca, Guadalajara, and Z ...

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") , ...

Discovery and naming

It contains a single

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

, ''Proa valdearinnoensis''. The generic name is from the Spanish word "proa" (meaning "prow"), which alludes to the pointed shape of the animal's

predentary Ornithischia () is an extinct order of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek s ...

bone; while the specific name is derived from Val de Ariño, the traditional name for the coal mines near where the first fossils were found. The animal was described on the basis of three partial skeletons and several skull elements from different individuals.

Description

''Proa'' is distinguished from other basal hadrosauriforms (especially other iguanodontids) in having a predentary that reaches the rostral margin, with divergent lateral processes. It can also be diagnosed by a unique combination of characters: dentary tooth row convex dorsally in lateral view; dentary tooth row extending caudal to the base of the coronoid process; platform between the dentary tooth row and the base of the coronoid process; coronoid process expanded along rostral and caudal margins; maxilla lacks a rostrodorsal process; quadrate straight in lateral view; ilium with dorsal margin convex dorsally, non-pendant supraacetabular process, and postacetabular process that tapers without a break in slope along its dorsal margin; cranial pubic process concave along its dorsal margin but lacks expansion of distal end.

Phylogeny

McDonald et al. (2012) recover ''Proa'' at the base of Hadrosauriformes along with ''

Iguanodon ''Iguanodon'' ( ; meaning 'iguana-tooth'), named in 1825, is a genus of iguanodontian dinosaur. While many species have been classified in the genus ''Iguanodon'', dating from the late Jurassic Period to the early Cretaceous Period of Asia, ...

''. In his osteology of ''

Hypselospinus ''Hypselospinus'' is a genus of iguanodontian dinosaur which was first described as a species of '' Iguanodon'' (''I. fittoni'') by Richard Lydekker in 1889, the specific name honouring William Henry Fitton. History In May 2010 the fossils c ...

'', Norman (2015) recovered ''Proa'' in a monophyletic Iguanodontidae as closer to the East Asian '' Bolong'' and ''

Jinzhousaurus ''Jinzhousaurus'' is a genus of hadrosauroid dinosaur of the Early Cretaceous of China. The type species is ''Jinzhousaurus yangi''. The generic name refers to the town Jinzhou. The specific name honours Yang Zhongjian as the founder of Chin ...

'' than to other European members of Iguanodontidae. Verdu ''et al'' (2017) recovered it as part of Eurasian clade including the Asian '' Xuwulong, Altirhinus,

Koshisaurus ''Koshisaurus'' is a monospecific genus of basal hadrosauroid from the Kitadani Formation in Japan. The discovery of the genus suggests that hadrosauroids had higher diversity along the eastern margin of Asia in the Early Cretaceous. "Koshi" m ...

'' and ''

Gongpoquansaurus ''Gongpoquansaurus'' (meaning "Gongpoquan reptile") is an extinct genus of basal hadrosauroid dinosaur that was not formally named until 2014, while the name was a ''nomen nudum'' for many years previously. It is known from IVPP V.11333, a par ...

.'' ''Proa'' was found in the most derived position as sister taxon to '' Batyrosaurus.''

References

Iguanodonts Early Cretaceous dinosaurs of Europe Albian life Cretaceous Spain Fossils of Spain Fossil taxa described in 2012 Taxa named by James I. Kirkland {{Ornithopod-stub