KOBAYASHI, YOSHITSUGU and YOICHI AZUMA, 2003. A NEW
IGUANODONTIAN (DINOSAURIA: ORNITHOPODA) FROM THE LOWER
CRETACEOUS KITADANI FORMATION OF FUKUI PREFECTURE, JAPAN.
Journal of Vertebrate Paleontology: Vol. 23, No. 1, pp.
166-175.
The skull material of a new iguanodontian dinosaur,
Fukuisaurus tetoriensis gen. et sp. nov., discovered from
the fluvial deposits of the Lower Cretaceous Kitadani
Formation, Tetori Group, Fukui Prefecture, Japan, is
described here. Some features of Fukuisaurus show
affinities with Iguanodon, Ouranosaurus, and Altirhinus,
referred to as Iguanodontidae by some. A phylogenetic
analysis using mainly cranial characters shows that
Fukuisaurus is a definitive derived non-hadrosaurid
iguanodontian and implies that Fukuisaurus is more
derived than the clade of Iguanodon + Ouranosaurus and
more basal to the clade of Altirhinus, Probactrosaurus,
Eolambia, Protohadros, Bactrosaurus, Telmatosaurus, and
hadrosaurids. It also supports that Iguanodontidae is
paraphyletic by the exclusion of Altirhinus as suggested
previously. The presence of Fukuisaurus indicates a wider
geographical distribution of the group in eastern Asia.
The occurrences of derived non-hadrosaurid iguanodontians
from the Kitadani Formation and other formations in Japan
support a dispersal of this group into eastern Asia by the
Early Cretaceous and its temporal range extension in
Japan. Fukuisaurus possesses a strong maxilla-vomer
articulation, indicative of the independent acquisition of
a non-pleurokinetic skull (not present in Hypsilophodon,
Iguanodon, and hadrosaurids).