Friday, 25 September 2020


Hoplites Bennettiana, Troyes, France
An excellent example of the ammonite, Hoplites bennettiana (Sowby, 1826) with a pathology. This beauty is from Albian deposits near Carrière de Courcelles, Villemoyenne, laid down in the Cretaceous near la région de Troyes, Aube,  Champagne in northeastern France.

The Albian is the youngest or uppermost subdivision of the Lower Cretaceous, approximately 113.0 ± 1.0 Ma to 100.5 ± 0.9 Ma (million years ago).

L'Albien or Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It was named after Alba, the Latin name for the River Aube, a tributary of the Seine that flows through the Champagne-Ardenne region of northwestern France.

At the time that this fellow was swimming in our oceans, ankylosaurs were strolling about Mongolia and stomping through the foliage in Utah, Kansas and Texas. Bony fish were swimming over what would become the strata making up Canada, the Czech Republic and Australia. Cartilaginous fish were prowling the western interior seaway of North America and a strange extinct herbivorous mammal, Eobaatar, was snuffling through Mongolia, Spain and England. 

Hoplites are amongst my favourite ammonites. I still have a difficult time telling them apart. To the right, you can see a slightly greyish, Hoplites maritimus, from Sussex England. 

Below him is a brownish Hoplites rudis from outcrops between Courcelles and Troyes, France. There are many Hoplites species. 

Each has the typical raised tire-track ribbing. My preference is for Hoplities bennetianus (or bennettiana). I'm still sorting out the naming of that species. The difference between Hoplites bennettiana and Hoplites dentatus is seen on the centre but I still find the distinctions subtle.

Hoplites shells have compressed, rectangular and trapezoidal whorl sections. They have pronounced umbilical bullae from which their prominent ribs branch out. The ends of the ribs can be both alternate or opposite. Some species have zigzagging ribs and these usually end thickened or raised into ventrolateral tubercles.

Photo One: Hoplites Bennettiana from near Troyes, France. Collection de Christophe Marot

Photo Two: Hoplites maritimus from Sussex, UK. Bottom: Hoplites rudis from near Troyes, France. Collection of Mark O'Dell