Matches in SemOpenAlex for { <https://semopenalex.org/work/W2087430103> ?p ?o ?g. }
Showing items 1 to 68 of
68
with 100 items per page.
- W2087430103 endingPage "469" @default.
- W2087430103 startingPage "409" @default.
- W2087430103 abstract "Lagynocystis pyramidalis (Barrande) from the marine Lower Ordovician of Bohemia (Šárka Formation (Llanvirn)), has features which suggest that it is ancestral, or nearly so, to living cephalochordates such as amphioxus ( Branchiostoma ). L. pyramidalis belongs to a strange group of fossils classified by some workers as ‘carpoid’ echinoderms (phylum Echinodermata, subphylum Homalozoa, class Stylophora). They are better seen, however, as primitive chordates with echinoderm affinities (phylum Chordata, subphylum Calcichordata Jefferies, 1967, class Stylophora). The most striking echinoderm-like feature of the calcichordates is their calcite skeleton with each plate a single crystal of calcite. Their chordate characters include: (1) branchial slits; (2) a postanal tail (stem) with muscle blocks, notochord, dorsal nerve cord and segmental ganglia; (3) a brain and cranial nervous system like those of a fish; and (4) various asymmetries like those of recent primitive chordates. The calcichordates are divided into a more primitive order, Cornuta, and a more advanced order Mitrata, which evolved from Cornuta. L. pyramidalis is a specialized member of the order Mitrata. Forms up till now associated with it in the suborder Lagynocystida of the Mitrata are better separated from it to form a new suborder Peltocystida (Kirkocystidae plus Peltocystidae). The features which ally L. pyramidalis to amphioxus are as follows: (1) a median ventral atrium opening by a median ventral atriopore; (2) a probably excretory posterior coelom which could give rise to the nephridia of amphioxus by upward growth of the gill slits; (3) evidence that the anus opened externally on the left; (4) evidence that the mouth and buccal cavity was innervated more strongly from the left than from the right; (5) evidence suggesting that, if it swam, L. pyramidalis would rotate about its long axis, clockwise as seen from behind, like late larval amphioxus and larval tunicates. The amphioxus-like features of L. pyramidalis are imposed on the pattern of a very primitive mitrate. There existed thus: (1) a well-developed brain and the cranial nerves were more of the vertebrate pattern than those of amphioxus; (2) left and right branchial openings in addition to the median atriopore; and (3) the tail or stem had paired segmental ganglia. The latest common ancestor of vertebrates and amphioxus would be a primitive mitrate. It follows, since Lagynocystis had a calcite skeleton, that such a skeleton has been lost at least twice in the evolution of the chordates." @default.
- W2087430103 created "2016-06-24" @default.
- W2087430103 creator A5037958011 @default.
- W2087430103 date "1973-06-21" @default.
- W2087430103 modified "2023-09-25" @default.
- W2087430103 title "The Ordovician fossil <i>Lagynocystis pyramidalis</i> (Barrande) and the ancestry of amphioxus" @default.
- W2087430103 cites W1509354250 @default.
- W2087430103 cites W1977224729 @default.
- W2087430103 cites W2013764007 @default.
- W2087430103 cites W2065673241 @default.
- W2087430103 cites W2072273025 @default.
- W2087430103 cites W2087049632 @default.
- W2087430103 cites W2105992191 @default.
- W2087430103 cites W2323644041 @default.
- W2087430103 doi "https://doi.org/10.1098/rstb.1973.0032" @default.
- W2087430103 hasPublicationYear "1973" @default.
- W2087430103 type Work @default.
- W2087430103 sameAs 2087430103 @default.
- W2087430103 citedByCount "47" @default.
- W2087430103 countsByYear W20874301032012 @default.
- W2087430103 countsByYear W20874301032019 @default.
- W2087430103 countsByYear W20874301032021 @default.
- W2087430103 countsByYear W20874301032022 @default.
- W2087430103 crossrefType "journal-article" @default.
- W2087430103 hasAuthorship W2087430103A5037958011 @default.
- W2087430103 hasConcept C104317684 @default.
- W2087430103 hasConcept C105702510 @default.
- W2087430103 hasConcept C151730666 @default.
- W2087430103 hasConcept C23785310 @default.
- W2087430103 hasConcept C2777929075 @default.
- W2087430103 hasConcept C2778534911 @default.
- W2087430103 hasConcept C2778712684 @default.
- W2087430103 hasConcept C2778961482 @default.
- W2087430103 hasConcept C55493867 @default.
- W2087430103 hasConcept C86803240 @default.
- W2087430103 hasConcept C91442348 @default.
- W2087430103 hasConceptScore W2087430103C104317684 @default.
- W2087430103 hasConceptScore W2087430103C105702510 @default.
- W2087430103 hasConceptScore W2087430103C151730666 @default.
- W2087430103 hasConceptScore W2087430103C23785310 @default.
- W2087430103 hasConceptScore W2087430103C2777929075 @default.
- W2087430103 hasConceptScore W2087430103C2778534911 @default.
- W2087430103 hasConceptScore W2087430103C2778712684 @default.
- W2087430103 hasConceptScore W2087430103C2778961482 @default.
- W2087430103 hasConceptScore W2087430103C55493867 @default.
- W2087430103 hasConceptScore W2087430103C86803240 @default.
- W2087430103 hasConceptScore W2087430103C91442348 @default.
- W2087430103 hasIssue "871" @default.
- W2087430103 hasLocation W20874301031 @default.
- W2087430103 hasOpenAccess W2087430103 @default.
- W2087430103 hasPrimaryLocation W20874301031 @default.
- W2087430103 hasRelatedWork W2002916455 @default.
- W2087430103 hasRelatedWork W2033908064 @default.
- W2087430103 hasRelatedWork W2062955619 @default.
- W2087430103 hasRelatedWork W2073652014 @default.
- W2087430103 hasRelatedWork W2131252653 @default.
- W2087430103 hasRelatedWork W2131278302 @default.
- W2087430103 hasRelatedWork W2131770907 @default.
- W2087430103 hasRelatedWork W2166338020 @default.
- W2087430103 hasRelatedWork W2921383982 @default.
- W2087430103 hasRelatedWork W3124642680 @default.
- W2087430103 hasVolume "265" @default.
- W2087430103 isParatext "false" @default.
- W2087430103 isRetracted "false" @default.
- W2087430103 magId "2087430103" @default.
- W2087430103 workType "article" @default.