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I've been looking at my specimens of Acrocoelites trisulculosus from the Toarcian Jet Rock (Mulgrave Shale Member = Falciferum Zone) of the north Yorkshire coast. This is an anoxic mudstone deposited during a prominent worldwide Ocean Anoxic Event (OAE) and, as might be expected, the preservation is very good. A number of them (7 so far) have a thin pyrite layer around the apex. This shows obvious lineation in all of them, mostly oblique to the axis of the rostrum. As pyrite is often associated with soft tissue decay, I strongly suspect that this is preserving musc
Megaonychites, form genus for the giant hooks that some belemnites have been shown to carry as a pair. By analogy with modern coleoids, they were probably carried by the males and used as mating claspers. This is a fairly large one at 3.4cm (the range is 0.5cm to about 4cm). It most likely belonged to a large Acrocoelites trisulculosus, by far the most common belemnite in these beds. Very rare in the UK but more frequent in the equivalent Holzmaden Posidonienschiefer. I've only seen one other from here - a partial - and that was mine until I gave it away thinking at
Please could anyone suggest what this is? I'm assuming fish, with little (less than 1mm) white spherules that might be teeth or denticles. From the Jet Rock (Mulgrave Shale Member) - a Lower Jurassic, Toarcian shale at least partly deposited in anoxic waters. Near Whitby, Yorkshire, UK. (Acquired in an auction as an extra with another fossil that I really wanted so I'm just curious really, I know little about fish!)
TqB posted a topic in Member CollectionsAt over 4" across, this is the last few chambers of by far the largest diameter belemnite phragmocone I've ever seen. (If anyone has one from a Megateuthis, I'd love to see it! - they don't seem ever to be preserved.) Given to me by a friend, it is in a nodule from the Jet Rock (Upper Lias, Lower Jurassic) of Port Mulgrave, north Yorkshire coast. It must have belonged to an exceptionally large Acrocoelites trisulculosus which is probably the only belemnite to occur in this bed. It's a large species anyway - typical rostra of it are 5 - 7" long but about 9" has very rarely bee