''Rioarribasuchus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

aetosaur Aetosaurs () are heavily armored reptiles belonging to the extinct order Aetosauria (; from Greek, (aetos, "eagle") and (, "lizard")). They were medium- to large-sized omnivorous or herbivorous pseudosuchians, part of the branch of archosaurs ...

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s have been found from the

Chinle Formation The Chinle Formation is an Upper Triassic continental geological formation of fluvial, lacustrine, and palustrine to eolian deposits spread across the U.S. states of Nevada, Utah, northern Arizona, western New Mexico, and western Colorado. In Ne ...

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

and

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

that date back to the upper Late

Carnian The Carnian (less commonly, Karnian) is the lowermost stage of the Upper Triassic Series (or earliest age of the Late Triassic Epoch). It lasted from 237 to 227 million years ago (Ma). The Carnian is preceded by the Ladinian and is followed by t ...

stage of the

Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch ...

History

''"

Desmatosuchus ''Desmatosuchus'' (, from Greek δεσμός ''desmos'' 'link' + σοῦχος ''soûkhos'' 'crocodile') is an extinct genus of archosaur belonging to the Order Aetosauria. It lived during the Late Triassic. Description ''Desmatosuchus'' was a ...

" chamaensis'' was named in 2003 and found from the

Petrified Forest Member The Petrified Forest Member is a stratigraphic unit of the Chinle Formation in Arizona, Colorado, New Mexico, Nevada, and Utah. It preserves fossils dating back to the Triassic period. Subunits Beds (are in alphabetical order, asterisks (*) ind ...

of the Chinle Formation in New Mexico. It was suggested to be more closely related to ''

Paratypothorax ''Paratypothorax'' is an extinct genus of aetosaur, known from a single species, ''Paratypothorax andressorum''. It was a broadly distributed member of the group found in Germany, North America, and possibly parts of Gondwana. The best specimen ...

'', and so Parker gave it the name ''Heliocanthus''. However, this new generic name was first proposed in an unpublished thesis, and thus did not meet

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the I ...

regulations for the naming of a new taxon. Later published papers reasserted the genetic separation of ''"D". chamaensis'' from ''Desmatosuchus'', but the name ''Heliocanthus'' remained a ''

nomen nudum In taxonomy, a ''nomen nudum'' ('naked name'; plural ''nomina nuda'') is a designation which looks exactly like a scientific name of an organism, and may have originally been intended to be one, but it has not been published with an adequate descr ...

'' until 2007, where it was thoroughly rediscribed in a paper published by the ''

Journal of Systematic Palaeontology The ''Journal of Systematic Palaeontolog'y'' (Print: , online: ) is a peer-reviewed scientific journal of palaeontology published by Taylor & Francis on behalf of the British Natural History Museum. , the editor-in-chief is Paul D. Taylor. T ...

''. However, a paper previously published in late 2006 assigned ''"D". chamaensis'' to the new genus ''Rioarribasuchus''. As a result, ''Heliocanthus'' is a junior objective synonym of ''Rioarribasuchus'' because the genus has seniority over ''Heliocanthus''. However, the name ''Rioarribasuchus'' has been viewed as a violation of the code of ethics laid out in Appendix A of the International Code of Zoological Nomenclature and the papers that made use of the name have even been described as practicing "intellectual theft". An article published later in 2007 in the science blog ''Tetrapod Zoology'' brought these events to the attention of a wider range of readers, and the controversy was dubbed "Aetogate". This sparked continued debate regarding these issues among vertebrate paleontologists, which eventually led to an investigation by the

Society of Vertebrate Paleontology The Society of Vertebrate Paleontology (SVP) is a professional organization that was founded in the United States in 1940 to advance the science of vertebrate paleontology around the world. Mission and Activities SVP has about 2,300 members inter ...

into these issues and a response given in mid 2008 regarding the unethical conduct of the authors who described ''Rioarribasuchus''.

References

External links

Tetrapod Zoology article explaining the taxonomic issues regarding ''Rioarribasuchus''PDF response given by the Society of Vertebrate Paleontology regarding the issues surrounding the naming and use of ''Rioarribasuchus''
Aetosaurs of North America Chinle fauna Prehistoric pseudosuchian genera {{paleo-archosaur-stub