Ceratopsian Month #04 – Auroraceratops rugosus

Auroraceratops (“dawn horned face”) lived during the Early Cretaceous of China (~130-100 mya). Around 2m long (6′6″), it had a shorter and wider snout than other early ceratopsians, with a more flattened broader head shape.

It was closely related to other small Asian species like Koreaceratops, and was probably primarily bipedal due to its proportionally short arms. But, since it falls at a transitional point in ceratopsian evolution between bipedal ancestors and quadrupedal later forms, it may have adopted a four-legged posture while feeding or moving at slow speeds.

Its skull had several patches of thickened bone, found directly in front of its eyes and on its lower jaw. These could have had some visible tough keratinous coverings in life – although I’ve not depicted any here – and could potentially have been used for pushing and butting during fights.

The back of its small frill shows evidence of attachment sites for its jaw muscles, suggesting that ceratopsian frills may have originally evolved to support large powerful chewing muscles before being secondarily modified into elaborate display structures.

Ceratopsian Month #03 – Aquilops americanus

Although most early ceratopsians are known from Asia, during the Early-to-Mid Cretaceous a few dispersed across to North America via a land connection in Beringia.

These migration events happened at least three times, and Aquilops (“eagle face”) was part of the first wave of immigrants, dating to 109-100 mya and representing one of the earliest ceratopsians discovered in North America. Known from a single tiny skull found in Montana, USA, its full size would have been only around 60cm long (2′) – about the size of a large rabbit.

The narrow triangular shape of its snout suggests it was probably a selective browser, feeding on leaves and soft shoots in low-level foliage. Its hooked beak also had a raised bump on the front, which may have supported a larger display structure such as a horn.