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Description
This lean, sprightly animal is Breviceratus cottonwoodensis, the first known member of the long lived and successful Xiphosaurids. In the modern world, large herds of these cursorial plains dwelling herbivores can be found on all continents except for Australia and Antarctica. However, their origins lay in the hot, steamy forests of Middle Eocene North America. Unlike modern members of its lineage, Breviceratus was a rather small, unassuming creature. Measuring just 3m in length and lacking the extensive cranial ornamentation present in today's Xiphosaurids, Breviceratus was nonetheless highly effective at escaping potential predators such as Boreonychine Dromaeosaurs by utilizing a rapid turn of speed. Indeed, velocity appears to have been a family trait in these animals from the very beginning. Xiphoceratids appear to be close relatives of the Rhododromines, forming a sister group with them in most phylogenetic studies and maybe even evolving from among them.

The former can be differentiated from the latter by a number of traits, including proportionally longer hind limbs, atrophied forelimbs, a longer, vaguely Lambeosaurine-like rostrum and the possession of a horn formed from a projection of the frontal and postorbital bones of the skull. What really set Xiphosaurids apart from other small Ornithischians were their teeth. Breviceratus already possessed a high tooth count when compared to Rhododromines, which seem to have been well suited for handling tough vegetation. In later Xiphosaurids, particularly the modern Xiphosaurine subfamily that originated in the Late Oligocene, these teeth had developed into chopping batteries of up to 800 tiny, scalpel blades. After the Late Eocene, Xiphosaurids became confined to Eurasia and would not return to their American homeland until the Late Miocene roughly 6 mya. The reasons for their extinction in North America are poorly understood, but competition from the outwardly similar but unrelated Presidioceratids may be to blame.

Illustrated by Sheather888. Check out his art at sheather888.deviantart.com

Description
This lean, sprightly animal is Breviceratus cottonwoodensis, the first known member of the long lived and successful Xiphosaurids. In the modern world, large herds of these cursorial plains dwelling herbivores can be found on all continents except for Australia and Antarctica. However, their origins lay in the hot, steamy forests of Middle Eocene North America. Unlike modern members of its lineage, Breviceratus was a rather small, unassuming creature. Measuring just 3m in length and lacking the extensive cranial ornamentation present in today's Xiphosaurids, Breviceratus was nonetheless highly effective at escaping potential predators such as Boreonychine Dromaeosaurs by utilizing a rapid turn of speed. Indeed, velocity appears to have been a family trait in these animals from the very beginning. Xiphoceratids appear to be close relatives of the Rhododromines, forming a sister group with them in most phylogenetic studies and maybe even evolving from among them.

The former can be differentiated from the latter by a number of traits, including proportionally longer hind limbs, atrophied forelimbs, a longer, vaguely Lambeosaurine-like rostrum and the possession of a horn formed from a projection of the frontal and postorbital bones of the skull. What really set Xiphosaurids apart from other small Ornithischians were their teeth. Breviceratus already possessed a high tooth count when compared to Rhododromines, which seem to have been well suited for handling tough vegetation. In later Xiphosaurids, particularly the modern Xiphosaurine subfamily that originated in the Late Oligocene, these teeth had developed into chopping batteries of up to 800 tiny, scalpel blades. After the Late Eocene, Xiphosaurids became confined to Eurasia and would not return to their American homeland until the Late Miocene roughly 6 mya. The reasons for their extinction in North America are poorly understood, but competition from the outwardly similar but unrelated Presidioceratids may be to blame.

Illustrated by Sheather888. Check out his art at sheather888.deviantart.com