''Notoceratops'' (meaning "southern horned face") is a

dubious Doubt is a mental state in which the mind remains suspended between two or more contradictory propositions, unable to be certain of any of them. Doubt on an emotional level is indecision between belief and disbelief. It may involve uncertainty ...

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 extinct

ornithischian 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 ...

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 ...

based on an incomplete, toothless left

dentary In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

(now lost) 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'', ...

Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and g ...

(in

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

), probably dating to the

Campanian The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campani ...

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval ...

. It was most likely a ceratopsian and it was found in the Lago Colhué Huapi Formation.

Discovery and naming

In 1918,

palaeontologist 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 ...

Augusto Tapia (1893–1966) discovered the genus

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 sever ...

. He also named 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 specime ...

, ''N. bonarellii'' (originally spelt as ''Notoceratops Bonarelli''), in 1918. The generic name is derived from Greek ''notos'', "the south", ''keras'', "horn" and ''ops'', "face". The specific name honours Guido Bonarelli (1871-1951), who advised Tapia in his study of the find. By present conventions the epithet is spelled ''bonarellii'', thus without a capital B. In many later publications the specific name is misspelled "bonarelli", with a single "i", from the incorrect assumption it would be derived from a Latinised "Bonarell~ius". The fossil, found near the Lago Colhué Huapi in Chubut, was eventually described by Friedrich von Huene in 1929, but it has since been lost.

Phylogeny

Originally referred as a

ceratopsian Ceratopsia or Ceratopia ( or ; Greek: "horned faces") is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic ...

by Tapia in 1918, it was later dismissed because no other members of that group were known from the Southern Hemisphere. However, the 2003 discovery of another possible ceratopsian, '' Serendipaceratops'', from Australia could change this view. ''Notoceratops'' has since been considered a '' nomen dubium'' and may have been a

hadrosaur Hadrosaurids (), or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod family, which incl ...

instead. An analysis published by Tom Rich ''et al''. in 2014, which focused on the validity of ''Serendipaceratops'', also examined the published material from ''Notoceratops''. They concluded that the holotype had ceratopsian features and that the genus is probably valid.

References

Ornithischian genera Late Cretaceous dinosaurs of South America Fossil taxa described in 1918 {{ornithischian-stub Cretaceous Argentina