''Morohasaurus'' is an extinct genus of ''cf.'' monstersaurian squamates know from a single left dentary from the Early Cretaceous (? Albian) Ohyamashimo Formation of the

Sasayama Group , formerly known as , is a city in the central eastern part of Hyōgo Prefecture, Japan. , the city had an estimated population of 40,050 in 17523 households and a population density of 110 persons per km2. The total area of the city is Geograph ...

in Tamba City, Hyogo Prefecture,

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

. The type and only species is ''Morohasaurus kamitakiensis.'' As of 2021, Ikeda ''et al.'' place this taxon ''a conferatur'' within Monstersauria based on general synapomorphies but without performing a phylogenetic analysis. The unique characters described in the paper to distinguish ''Morohasaurus kamitakiensis'' as a valid species include "the sinuous posteroventral rim of the dentary with a large U-shaped upper notch and small V-shaped lower notch, posteroventral corner of intramandibular septum with a weakly pointed eminence projecting posteriorly, and unicuspid, curved trenchant teeth with distinct blade-like

carinae ''Carinae'' was an area of ancient Rome. It was one of its most exclusive neighborhoods, where many of the senatorial class lived. Florus described the ''Carinae'' as the "''most celebrated part of the city''" (''celeberrima pars urbis''). Des ...

on their mesial and distal sides without grooves or serrations." If its presumed affinities are correct, ''Morohasaurus'' represents the oldest known monstersaurian to date.

References

Anguimorpha Cretaceous lizards Early Cretaceous reptiles Fossil taxa described in 2021 {{lizard-stub