''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 nom ...

of basal styracosternan

iguanodont Iguanodontia (the iguanodonts) is a clade of herbivorous dinosaurs that lived from the Middle Jurassic to Late Cretaceous. Some members include ''Camptosaurus'', ''Dryosaurus'', ''Iguanodon'', '' Tenontosaurus'', and the hadrosaurids or "duck-bil ...

known from the Early Cretaceous Escucha Formation (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 ± 0 ...

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 Za ...

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 ...

Discovery and naming

It contains a single

species In biology, a species is the basic unit of 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 the appropriate s ...

, ''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 st ...

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 co ...

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

Bolong ''Bolong'' (meaning "Bo's dragon") is a genus of iguanodontian dinosaur known from the Early Cretaceous-age Yixian Formation of western Liaoning Province, China. It lived about 125 million years ago in the earliest Aptian. Discovery and naming ...

'' 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 Chine ...

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