Tuesday 30 July 2013

Nodosaurid teeth from the Early Cretaceous of southern England.

The Nodosaurids were a group of Ankylosaurid Dinosaurs that differed from other members of the group in having spines, rather than boney clubs, on the ends of their tails, and additional large spines on their shoulders. Most known Nodosaurids have been discovered in North America, but specimens are known from China, Antarctica and England.

In a provisional paper to be published in the journal Acta Palaeontologica Polonica and available online from 13 March 2013, William Blows of the Department of Applied Biological Sciences at City University London and Kerri Honeysett of Bexhill on Sea in East Sussex describe four Nodosaurid teeth from the Isle of Wight and Bexhill on Sea. 

These are distinctive enough to state that they are from a Nodosaurid, but are not assigned to species level, since none of the Nodosaurid specimens known from England has preserved teeth, making it impossible to assign the teeth with confidence to any previously described species, or to say with confidence that they belong to a new species.

The first specimen comes from a plant dedris bed within the the Sudmore Point Sandstone at Sudmore Point east of Brook Chine on the Isle of Wight. It is Barremian in age (between 125 and 129.4 million years old). The Sudmore Point Sandstone is interpreted as having formed on a flat floodplain, with the debris bed representing a flood event. It contains large amounts of disarticulated plant and animal remains. The tooth is nearly complete, comprising both the crown and root, with a total length of 17 mm, 6 mm of which is the crown. 

The Isle of Wight specimen in (A) labial(?) view, (B) distal view and (C) lingual(?) view. Scale bar is 4 mm. Blows and Honeysett (2013).

The other three teeth come from Ashdown Quarry at Bexhill on Sea, where they were located by David Brockhurst, a noted amateur palaeontologist employed at the quarry. They were located within a conglomerate within the Wadhurst Clay Formation, of Valanginian age, making them between 132.9 and 139.8 million years old. 

The first of these is a 20.5 mm tooth with both crown and root, the crown comprising 7 mm of the total. The second is a partial crown 5 mm in heigh, without any root. The third is a 17 mm tooth of which 5 mm is the crown and the remainder is the root; the crown of this tooth appears somewhat worn down.

The first Bexhill on Sea specimen, complete tooth in (A1) lingual(?) view and  (A2) labial(?) view. Blows and Honeysett (2013).

The second and third Bexhil on Sea specimens. Partial tooth in shown in opposite views (B1 and B2), and complete tooth in (C1) lingual(?) view, (C2) distal view, (C3) labial(?) view. Blows and Honeysett (2013).

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