Ovaticeras is a somewhat rarer ammonite which seems to be very restricted, both in terms of local distribution (it’s apparently only really documented from Britain, with its main occurrence in Yorkshire) and in terms of its relative short-livedness (it has only been found in the approx. 35 cm of the so called ovatum bed at the top of the falciferum subzone of the lower toarcian (of course named after the species O. ovatum) and shortly below it. It is thought to have descended from Harpocas falciferum (HOWARTH 1992) and apparently left no descendants itself – end of the line.

I have found Ovaticeras ovatum at Saltwick Bay, at Hawsker and at Ravenscar, but you should be able to find it everywhere on the Yorkshire coast,
where there’s an outcrop of the aforementioned bed.

The oval whorl shape of Ovaticeras is quite characteristic, as are the sloping umbilical walls without an edge,
which differentiates it from large Eleganticeras body chambers.

Adult specimen have  a bit of a “hood” at the end of the body chamber, where the keel slightly overarches the whorl.
The ribs are those of a typical Harpoceratid, of weak falcoid form, receding to mere sinuous growth stripes on adult specimens’ body chambers.
It does have a simple keel with smooth areas to the side of it that also grows weaker on large body chambers.

This large, 17 cm, complete specimen was found on Oct 7, 1991 at Saltwick Bay in a large nodule with a strong pyrite crust and was
extracted from the nodule using hammer and small chisels alone (on the kitchen table of our holiday flat, if you need to know…)
It is not my prettiest specimen, but my largest and the first of the species I’ve found.

This partial specimen shows the nice characteristical sutures of Ovaticeras.
Must be getting close to Christmas, I see Christmas trees everywhere…

AndyS