Department of Geology

Approximately 40% of a skeleton including cranial and postcranial remains representing a
new genus and species of basal neotheropod dinosaur is described. It was collected from
fallen blocks from a sea cliff that exposes Late Triassic and Early Jurassic marine and quasi
marine strata on the south Wales coast near the city of Cardiff. Matrix comparisons indicate
that the specimen is from the lithological Jurassic part of the sequence, below the first
occurrence of the index ammonite Psiloceras planorbis and above the last occurrence of
the Rhaetian conodont Chirodella verecunda. Associated fauna of echinoderms and
bivalves indicate that the specimen had drifted out to sea, presumably from the nearby
Welsh Massif and associated islands (St David’s Archipelago). Its occurrence close to the
base of the Blue Lias Formation (Lower Jurassic, Hettangian) makes it the oldest known
Jurassic dinosaur and it represents the first dinosaur skeleton from the Jurassic of Wales. A
cladistic analysis indicates basal neotheropodan affinities, but the specimen retains plesiomorphic
characters which it shares with Tawa and Daemonosaurus.
Introduction