Search the Community
Showing results for tags 'epirostrum'.
-
A lovely 18" belemnite slab I've bought for my birthday (birthday belemnites are a bit of a tradition!). From the Jurassic Posidonienschiefer (Toarcian, Upper Lias) of Holzmaden - a very interesting and unusual selection of mostly the same species, one with a nice epirostrum. Not quite sure of the actual species, but it's close to Acrocoelites subtenuis and A. gracilis - neither of which usually have epirostra (the squashed bit at the tip of photo 2). It also contains a couple of bonus teeth including a Hybodus type which Sebastian @belemniten tells me is a rarity there. Apart from the fact it's a great display piece, the main reason I bought it is its faunal similarity to the basal beds of the Alum Shales around Whitby in Yorkshire, known as the "Hard Shales" (Toarcian, Bifrons Zone). There, you get accumulations of Acrocoelites subtenuis at the same sort of density - possibly conspecific with these, but never showing an epirostrum. One possible reason for this is that the epirostrum is a sexual dimorphism, connected with breeding grounds, so they only occur in specific areas at any given time. Or it may just be a different species... form with short epirostrum: orthorostrum:
- 15 replies
-
- 9
-
- acrocoelites
- belemnite battlefield
- (and 4 more)
-
An extreme morphology, much of the length consisting of an epirostrum - an overgrowth and extension of the normal rostrum. This may have been aragonitic and partially organic and is frequently crushed. Described under Youngibelus tubularis: Doyle, P. 1990-92 The British Toacian (Lower Jurassic) Belemnites. Monograph of the Palaeontographical Society, London: Part 2, 50-79, pls.18-28 (Publ. No. 587, vol. 145) Cuspiteuthis Abel 1916 was re-established as senior synonym of Youngibelus Riegraf in: Riegraf, W, Janssen, N.M.M & Schmitt-Riegraf, C. 1998. Cephalopoda dibranchiata fossiles (Coleoidea)II. -(In:) Westphal, F. (ed.) Fossilium Catalogus. 1: Animalia, Pars 135: 1-519, Leiden (Backhuys).
-
- 1
-
- alum shales
- cuspiteuthis
-
(and 2 more)
Tagged with: