''Albalophosaurus'' (meaning 'white crest lizard') 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 ceratopsian ornithischian

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 ...

. It was described in 2009 from remains found in 1997 by Yoshinori Kobayashi from the

Kuwajima Formation The Kuwajima Formation is an Early Cretaceous geologic formation in Japan. Its precise age is uncertain due to a lack of identifying fossils, and it was previously considered likely Valanginian to Hauterivian in age. However, it is now considered ...

of central Japan, outcropping in Hakusan in the Ishikawa Prefecture. 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 sever ...

, SBEI 176, consists of cranial bones from an incomplete, disarticulated skull and left lower jaw thought to belong to a single individual. 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 ...

is named ''A. yamaguchiorum''. The generic name is derived from

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 of the ...

''albus'', "white", and

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

λόϕος (''lophos''), "crest", a reference to the snow-covered crest of Mount Hakusan. The specific name honours Ichio Yamaguchi and Mikiko Yamaguchi, who discovered and prepared many fossils from the site. The exact age of the strata from which the remains of ''Albalophosaurus'' have been found is not known because of the lack of marine beds containing

index fossil Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them.Hine, Robert. “Biostratigraphy.” ''Oxford Reference: Dictionary of Bio ...

s, but the Kuwajima Formation is known to have formed during the Early Cretaceous, most likely after the

Berriasian In the geological timescale, the Berriasian is an age/stage of the Early/Lower Cretaceous. It is the oldest subdivision in the entire Cretaceous. It has been taken to span the time between 145.0 ± 4.0 Ma and 139.8 ± 3.0 Ma (million years ago ...

and before the

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 precede ...

based on the ages of underlying and overlying formations. More recent studies suggest that the age of the Kuwajima Formation is most likely

Valanginian In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 139.8 ± 3.0 Ma and 132.9 ± 2.0 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretace ...

—

Hauterivian The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous Epoch or a stage in the Lower Cretaceous Series. It spans the time between 132.9 ± 2 Ma and 129.4 ± 1.5 Ma (million years ago). The Hauterivian is preceded by the ...

, although the exact age is still uncertain.

Phylogeny

Although ''Albalophosaurus'' was classified as a basal ceratopsian in a

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

analysis conducted along with the description of the genus, only one ambiguous

synapomorphy In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ...

of the clade is present in the holotype, and none of the unambiguous synapomorphies that define Ceratopsia are present. Other characteristics, such as those of the dental

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines * Morphology (archaeology), study of the shapes or forms of artifacts * Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...

of ''Albalophosaurus'', seem to suggest that the genus shares a relation to

Ornithopoda Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (), that started out as small, bipedal running grazers and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous worl ...

. Thus the authors of the original description of the genus refer it to Cerapoda ''

incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertain ...

'', and do not consider it to be a ceratopsian. Han ''et al.'', 2012 found ''Albalophosaurus'' to be a ceratopsian more derived than '' Micropachycephalosaurus'', ''

Yinlong ''Yinlong'' (, meaning "hidden dragon") is a genus of basal ceratopsian dinosaur from the Late Jurassic Period of central Asia. It was a small, primarily bipedal herbivore. Discovery and species A coalition of American and Chinese paleontolo ...

'', ''

Stenopelix ''Stenopelix'' (meaning "narrow pelvis") is a genus of small marginocephalian dinosaur, possibly a basal ceratopsian, from the Early Cretaceous of Germany. It lived in the late Berriasian Stage of the Cretaceous period, approximately 140 myr ag ...

'', and '' Chaoyangosaurus'', but basal to a clade composed of ''

Psittacosaurus ''Psittacosaurus'' ( ; "parrot lizard") is a genus of extinct ceratopsian dinosaur from the Early Cretaceous of what is now Asia, existing between 126 and 101 million years ago. It is notable for being the most species-rich non-avian dinosaur gen ...

'' and more derived ceratopsians.

References

{{Taxonbar, from=Q192389 Ceratopsians Ornithischian genera Early Cretaceous dinosaurs of Asia Fossils of Japan Fossil taxa described in 2009