''Riparovenator'' ("riverbank hunter") 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 ...

baryonychine Baryonychinae is an extinct clade or subfamily of spinosaurids from the Early Cretaceous (Valanginian-Albian) of Britain, Portugal, and Niger. In 2021, it consisted of six genera: '' Ceratosuchops'', ''Cristatusaurus'', ''Riparovenator'', ''Suc ...

spinosaurid The Spinosauridae (or spinosaurids) are a clade or family of tetanuran theropod dinosaurs comprising ten to seventeen known genera. They came into prominence during the Cretaceous period. Spinosaurid fossils have been recovered worldwide, includi ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

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 ...

(

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma ( million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is pre ...

)

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

of Britain, the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

is ''Riparovenator milnerae''.

Discovery and naming

Between 2013 and 2017, spinosaurid fossils were uncovered at the beach near the

Chilton Chine The Chilton Chine is a geological feature on the south west coast of the Isle of Wight, England. It lies to the west of the village of Brighstone. It is a small coastal gully, one of a number of such chines on the island created by stream ero ...

before being brought to

Dinosaur Isle Dinosaur Isle is a purpose-built dinosaur museum located in Sandown on the Isle of Wight in southern England. The museum was designed by Isle of Wight architect Rainey Petrie Johns in the shape of a giant pterosaur. It claims to be the first cu ...

. Such remains had been generally referred to ''

Baryonyx ''Baryonyx'' () is a genus of theropod dinosaur which lived in the Barremian stage of the Early Cretaceous period, about 130–125 million years ago. The first skeleton was discovered in 1983 in the Smokejack Clay Pit, of Surrey, England, in ...

'' but were understood recently to represent two species new to science. In 2021, the

''Riparovenator milnerae'' was named and described by a team of

palaeontologists Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

including Chris T. Barker, David William Elliot Hone,

Darren Naish Darren William Naish is a British vertebrate palaeontologist, author and science communicator. As a researcher, he is best known for his work describing and reevaluating dinosaurs and other Mesozoic reptiles, including '' Eotyrannus'', ''Xeno ...

, Andrea Cau, Jeremy A.F. Lockwood, Brian Foster, Claire E. Clarkin, Philipp Schneider and Neil John Gostling. The generic name is derived from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power ...

''rīpārius'', "of the river bank", and ''vēnātor'', "hunter". The specific name honors

Angela Milner Angela Cheryl Milner (3 October 1947 – 13 August 2021) was a British paleontologist who, in 1986 alongside Alan Charig, described the dinosaur '' Baryonyx''. Early life Milner was born Angela Girven in Gosforth, daughter of Cyril and L ...

, deceased in August 2021. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

remains of this taxon consist of IWCMS 2014.95.6 (premaxillary bodies), IWCMS 2014.96.1, 2; 2020.448.1, 2 (a disarticulated braincase) and IWCMS 2014.96.3 (a partial lacrimal and prefrontal), all of which were recovered from rocks in the Chilton Chine of the

Wessex Formation The Wessex Formation is a fossil-rich English geological formation that dates from the Berriasian to Barremian stages (about 145–125 million years ago) of the Early Cretaceous. It forms part of the Wealden Group and underlies the younger Vec ...

. Referred remains include a posterior nasal fragment (IWCMS 2014.95.7) and an extensive caudal axial series of twenty-two vertebrae (IWCMS 2020.447.1-39), representing around fifty individual bones in total.

Description

''Riparovenator'' is estimated to have measured about 8.5 metres (28 feet) in length based on the skeletal reconstruction in the describing paper by Dan Folkes.

Classification

In 2021, ''Riparovenator'' was, within

Spinosauridae The Spinosauridae (or spinosaurids) are a clade or family of tetanuran theropod dinosaurs comprising ten to seventeen known genera. They came into prominence during the Cretaceous period. Spinosaurid fossils have been recovered worldwide, includ ...

, placed into the

Baryonychinae Baryonychinae is an extinct clade or subfamily of spinosaurids from the Early Cretaceous (Valanginian-Albian) of Britain, Portugal, and Niger. In 2021, it consisted of six genera: '' Ceratosuchops'', '' Cristatusaurus'', ''Riparovenator'', ''Su ...

. The authors in a

cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived ch ...

analysis recovered ''Riparovenator'' as a member of the newly erected clade,

Ceratosuchopsini Baryonychinae is an extinct clade or subfamily of spinosaurids from the Early Cretaceous (Valanginian-Albian) of Britain, Portugal, and Niger. In 2021, it consisted of six genera: '' Ceratosuchops'', '' Cristatusaurus'', '' Riparovenator'', ''S ...

, closely related to ''

Suchomimus ''Suchomimus'' (meaning "crocodile mimic") is a genus of spinosaurid dinosaur that lived between 125 and 112 million years ago in what is now Niger, during the Aptian to early Albian stages of the Early Cretaceous period. It was named an ...

'' and the coeval ''

Ceratosuchops ''Ceratosuchops'' (meaning "horned crocodile face") is a genus of spinosaurid from the Early Cretaceous ( Barremian) of Britain. Discovery and naming In 2021, the type species ''C. inferodios'' was named and described by a team of paleo ...

'', its

sister species In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

Palaeoecology

''Riparovenator'' lived in a dry Mediterranean habitat in the

, where rivers were home to riparian galleries. Like most spinosaurids, it would have fed on aquatic prey as well as other terrestrial prey in these areas.

References

Spinosaurids Monotypic dinosaur genera Barremian life Early Cretaceous dinosaurs of Europe Cretaceous England Fossils of England Fossil taxa described in 2021 Taxa named by Darren Naish {{theropod-stub