New species of fossil crinoid discovered in south Wales

The discovery of any new type of fossil is one of the most exciting things that can happen to a palaeontologist. A new fossil discovered in south Wales – and the only one known of its kind - has been given the name Hylodecrinus cymrus to illustrate its Welsh origins.

Whilst on a field trip to Pembrokeshire in 2009 to study the 350 million year old (Carboniferous Period) rocks in a small cove at West Angle Bay, Cindy Howells, a palaeontology curator at Amgueddfa Cymru, discovered an interesting new fossil that did not match any scientifically recorded specimen. In the Carboniferous Period Wales was located close to the equator and was covered with shallow tropical seas. The rocks here suggest there were many fierce tropical storms which usually smashed the shells of marine organisms into small pieces before they were fossilised. However a few layers contain whole fossils, deposited in quieter conditions, and in one of these the new specimen was found.

Reconstruction of Hylodecrinus cymrus.

The fossil is a crinoid, a small marine animal that looked a little like a plant. Crinoids have a long flexible stem, anchored into the sea-bed. This is topped with a small cup shaped structure containing its internal organs. Long flexible feathery tentacles, or arms, are extended up above the animal and these collect micro-organisms from the seawater and channel them down to its stomach.

The new fossil was carefully extracted from the rocks and taken back to Cardiff. After consultation with Professor Tom Kammer from West Virginia University (an expert on Carboniferous crinoids), it was decided that this fossil was a new species and also belonged to a group never seen before outside the USA. It has been given the name Hylodecrinus cymrus to illustrate its Welsh origins. The description of this new fossil was published online in the Geological Journal. This specimen becomes the ‘type’ specimen of the species, against which others may be compared.

As of 2013, it is the only known specimen of this species.

The tropical seas of the Carboniferous Period were teeming with life including brachiopods, bivalves, gastropods, corals, fish and particularly crinoids. Rocks of this age are especially well exposed along the south Wales coastline, from Glamorgan to Pembrokeshire. Studies on fossils help us to understand how these rocks were deposited, and the conditions in which the animals preserved within them would have lived.