“Hadrosauridae, a household of big herbivorous dinosaurs, were amongst the most plentiful dinosaurs of Late Cretaceous terrestrial environments of the Western Interior Basin of North America for about 20 million years,”stated Montana State University paleontologist Sebastian Dalman and his associates from Harrisburg University, Penn State University, New Mexico Museum of Natural History and Pavol Jozef Šafárik University.

“This group, typically called the ‘duck-billed’ dinosaurs, was among the most taxonomically varied and effective dinosaur groups throughout the Cretaceous.”

“During the last 20 million years of the Cretaceous, hadrosaurids accomplished a worldwide circulation and existed in Africa, Antarctica, Asia, Europe, and North and South America.”

Called Ahshislesaurus wimanithe brand-new hadrosaurid types lived throughout the Late Cretaceous, around 75 million years earlier.

The dinosaur’s fossilized bones were discovered in the layers of the Kirtland Formation in the Ah-shi-sle-pah Wilderness, which lies in San Juan County, New Mexico, in between Chaco Canyon and the De-na-zin Wilderness.

“The holotype specimen includes an insufficient diagnostic skull, a number of separated cranial components consisting of the best jugal, quadrate, dentary, and surangular, and a series of articulated cervical vertebrae,” the scientists stated.

“In addition to the holotype, a number of specimens from the very same layers might likewise come from this newly-identified types, consisting of an unspoiled left dentary and a partial skeleton, in addition to 2 humeri, one coming from a big adult and the other to a juvenile.”

In previous research studies, Ahshislesaurus wimani was described Kritosaurusa more youthful genus of saurolophine hadrosaurid from the Kirtland Formation.

Both types are reasonably carefully associated within the hadrosaurid subfamily Saurolophinae.

According to the phylogenetic analysis, they represent 2 unique groups that were present throughout the Campanian age of the Cretaceous in southern Laramidia.

“The stratigraphically more youthful Kritosaurus belongs to the Kritosaurini clade that consists of a number of northern Laramidian types,” the researchers stated.

“Furthermore, the phylogenetic outcomes recommend that the clade that consists of Ahshislesaurus and Naashoibitosaurusin addition to 2 unnamed types from southern Laramidia, divided from Kritosaurini throughout the Late Campanian (75 million years ago).”

According to the group, together with Naashoibitosaurus Ahshislesaurus kinds a possibly brand-new group of flat-headed saurolophine hadrosaurids.

“This clade recommends the saurolophines were a taxonomically varied group, which, throughout the last 20 million years of the Cretaceous, were amongst the dominant herbivorous dinosaurs in southern Laramidia,” the authors stated.

“Recognition of a brand-new hadrosaurid types from New Mexico likewise supplies more proof for latitudinal variation in the hadrosaurid animals throughout the Late Cretaceous in Laramidia.”

The group’s paper will be released in the New Mexico Museum of Natural History and Science Bulletin

_____

Sebastian Dalman et al2025. A brand-new saurolophine hadrosaurid (Ornithischia: Hadrosauridae) from the Upper Cretaceous (Campanian) Hunter Wash Member, Kirtland Formation, San Juan Basin, New Mexico. New Mexico Museum of Natural History and Science Bulletin 101