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Showing results for tags 'stylophora'.
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So...... let's say I wanted to collect one specimen of each class of echinoderms (yes, the classes are always in flux, I know). Not a great specimen, just some ossicle or fragment easily determinable to be a member of that class for each class. It would be a fun trip around the world going to a set of localities, each of which was the easiest place in the world to find specimens of some particular echinoderm class. Some classes (crinoids, echinoids) seem almost too easy; others (blastoids, cyclocystoids, paracrinoids) are hard in some parts of the world but trivially easy here in eastern Missouri, USA. But more obscure classes of echinoderms (ctenocystoids, cinctans, solutans, stylophorans) seem to be hard to find no matter where you go; for each of these, I'm curious what formation / location would be the *least* hard. So let's start with a weird one: Where in the world is it *least difficult* to find a fossil readily determinable as belonging to an ophiocistioid?
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- asteroidea
- asterozoa
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Tagged with:
- asteroidea
- asterozoa
- blastoidea
- blastozoa
- cincta
- coronoidea
- crinoidea
- crinozoa
- cryptocrinoidea
- ctenocystoidea
- cyclocystoidea
- diploporita
- echinodermata
- echinoidea
- echinozoa
- edrioasteroidea
- eocrinoidea
- helicoplacoidea
- holothuroidea
- homalozoa
- ophiocistioidea
- ophiuroidea
- parablastoidea
- paracrinoidea
- rhombifera
- soluta
- somasteroidea
- stenuroidea
- stylophora
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Lagynocystis pyramidalis was first described and figured by Barrande 1887 under the name Anomalocystites pyramidalis. Taxonomy from Parsley, 2000. Lagynocystis pyramidalis (Barrande) from the marine Lower Ordovician of Bohemia, has features which suggest that it is ancestral, or nearly so, to living cephalochordates such as amphioxus (Branchiostoma). Diagnosis from Parsley 2000, p. 258: "Ankyroid with asymmetrical theca. M‘l—M'5 well developed: MI—M3 shortened and reduced in size: M4 and M5 absent; large CS plate. M‘5 protuberant, hollow. Sutures with M’4 and in some specimens narrowly sutured with M'3 but not flexibly articulated. Superior face with distally overlapping platelets that wrap around onto inferior face near posterior ends. Proximal aulacophore with multiplated meres; styloid with four or five denticulate cups; distal aulacophore atypically long with elongate ossicles and tall rectangular cover plates." Line drawing from Parsley 2000, p. 255: References: Barrande, J. (1887). Classe des Echinodermes. Ordre des cystidées, p. 1–233. In Systême silurien du centre de la Bohême, 7. Rivnác (Prague) and Gerhard (Leipzig). Jefferies R. P. S. (1973). The Ordovician fossil Lagynocystis pyramidalis (Barrande) and the ancestry of amphioxus Phil. Trans. R. Soc. Lond. B265, pp. 409–469. Parsley, R. L. (2000). Morphological and Paleoecolgical Analysis of the Ordovician Ankyroid Lagynocystis (Stylophora: Echinodermata). Journal of Paleontology, 74(2), 254–262.
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