[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Aquilops, new ceratopsian from Lower Cretaceous of Montana, oldest in North America

Ben Creisler

New in PLoS ONE:

Andrew A. Farke, W. Desmond Maxwell, Richard L. Cifelli &  Mathew J.
Wedel (2014)
A Ceratopsian Dinosaur from the Lower Cretaceous of Western North
America, and the Biogeography of Neoceratopsia.
PLoS ONE 9(12): e112055.

The fossil record for neoceratopsian (horned) dinosaurs in the Lower
Cretaceous of North America primarily comprises isolated teeth and
postcrania of limited taxonomic resolution, hampering previous efforts
to reconstruct the early evolution of this group in North America. An
associated cranium and lower jaw from the Cloverly Formation
(?middle–late Albian, between 104 and 109 million years old) of
southern Montana is designated as the holotype for Aquilops americanus
gen. et sp. nov. Aquilops americanus is distinguished by several
autapomorphies, including a strongly hooked rostral bone with a
midline boss and an elongate and sharply pointed antorbital fossa. The
skull in the only known specimen is comparatively small, measuring 84
mm between the tips of the rostral and jugal. The taxon is interpreted
as a basal neoceratopsian closely related to Early Cretaceous Asian
taxa, such as Liaoceratops and Auroraceratops. Biogeographically, A.
americanus probably originated via a dispersal from Asia into North
America; the exact route of this dispersal is ambiguous, although a
Beringian rather than European route seems more likely in light of the
absence of ceratopsians in the Early Cretaceous of Europe. Other
amniote clades show similar biogeographic patterns, supporting an
intercontinental migratory event between Asia and North America during
the late Early Cretaceous. The temporal and geographic distribution of
Upper Cretaceous neoceratopsians (leptoceratopsids and ceratopsoids)
suggests at least intermittent connections between North America and
Asia through the early Late Cretaceous, likely followed by an interval
of isolation and finally reconnection during the latest Cretaceous.

News and blogs: