Post by Joe Botting on Aug 13, 2005 14:16:09 GMT -5
Hi all,
I spent friday finally going through the bryozoans that we collected mostly from sandstones of the Builth Volcanic Group last summer, and trying to work out how many species there were. We thought there were probably at least seven, but it turns out to have been an underestimate. I'm confident of about 20, and there are probably several more as well. And that's before going into the limestones to compare internal structures, which is normally the only way to reliably distinguish the beastly little things.
Among the more unusual ones is one with star-shaped pores, a feature I can't find in any published examples so far... at least, I think it's a bryozoan. Stellate pores are the norm for a lot of early tabulate corals.
There's also the trace of a boring ctenostome(?) bryozoan. I do, of course, mean boring in the sense of etching; the skeleton decays, but the marks it gouged into the brachiopod shell that it lived on remain.
Overall, there seem to be trepostomes, cystoporates, cyclostomes, fenestellids, and probably some others. In other words, it's a really diverse biota. The most useful aspect of them, though, is that we think we can see clear distribution patterns that relate to water depth or turbulence, or something. They seem almost to have been more sensitive to these things than the brachiopods and sponges. In combination, they'll hopefully help to show ecological patterns in the Builth shallow-water faunas even more clearly than we can already.
I know why everyone ignores them, though - they're a real pain to try to work with from mouldic fragments (i.e. what we normally get). They're quite gorgeous when one gets to know them, though. There's a surprising amount of fun to be had from trying to deal with the really tricky fossils. Honest.
Oh, and there are now drawings of another 10 species on the faunal list!
joe
I spent friday finally going through the bryozoans that we collected mostly from sandstones of the Builth Volcanic Group last summer, and trying to work out how many species there were. We thought there were probably at least seven, but it turns out to have been an underestimate. I'm confident of about 20, and there are probably several more as well. And that's before going into the limestones to compare internal structures, which is normally the only way to reliably distinguish the beastly little things.
Among the more unusual ones is one with star-shaped pores, a feature I can't find in any published examples so far... at least, I think it's a bryozoan. Stellate pores are the norm for a lot of early tabulate corals.
There's also the trace of a boring ctenostome(?) bryozoan. I do, of course, mean boring in the sense of etching; the skeleton decays, but the marks it gouged into the brachiopod shell that it lived on remain.
Overall, there seem to be trepostomes, cystoporates, cyclostomes, fenestellids, and probably some others. In other words, it's a really diverse biota. The most useful aspect of them, though, is that we think we can see clear distribution patterns that relate to water depth or turbulence, or something. They seem almost to have been more sensitive to these things than the brachiopods and sponges. In combination, they'll hopefully help to show ecological patterns in the Builth shallow-water faunas even more clearly than we can already.
I know why everyone ignores them, though - they're a real pain to try to work with from mouldic fragments (i.e. what we normally get). They're quite gorgeous when one gets to know them, though. There's a surprising amount of fun to be had from trying to deal with the really tricky fossils. Honest.
Oh, and there are now drawings of another 10 species on the faunal list!
joe