2004 Denver Annual Meeting (November 7–10, 2004)

Paper No. 13
Presentation Time: 4:45 PM


SIVETER, Derek J.1, SUTTON, Mark D.1, BRIGGS, Derek E.G.2 and SIVETER, David J.3, (1)Department of Earth Sciences, Univ of Oxford, Parks Road, Oxford, OX1 3PR, (2)Department of Geology and Geophysics, Univ of Yale, P.O. Box 208109, New Haven, CT06520-8109, (3)Department of Geology, Univ of Leicester, University Road, Leicester, LE1 7RH, derek.siveter@earth.ox.ac.uk

The Herefordshire (Silurian) Konservat-Lagerstätte in England yields remarkable, three-dimensional, non-biomineralized fossils in carbonate concretions hosted in a volcaniclastic deposit. Pycnogonids (sea spiders) have an extremely sparse fossil record, and are known globally from just four species based on a few tens of specimens from two localities. A new, exceptionally preserved sea spider from the Herefordshire deposit represents the oldest known adult by some 35 million years, the most completely known fossil species, and provides new insight into the early morphology of the Pycnogonida and its relationship to other arthropod groups. The morphology of this recently discovered form has been digitally reconstructed to produce a ‘virtual fossil’ in the round.