| 词条 | Melanosclerite |
| 释义 |
| taxon = Melanoscleritoitidae | fossil_range = {{Fossil range | Lower Cambrian | Frasnian|refs=[1] }} }} The Melanosclerites are a group of problematic microfossils obtained by palynological processing. MorphologyThe form-taxon contains a wide array of rod-like fossils, 100 µm to some mm long, that culminate in a broad bulbous 'head', often separated from the stalk by a constriction.[1] The bulbous end may bear broad 'prongs', giving the appearance of the end of a human femur where the prongs are paired, although the prongs often occur in higher number – five, six, a dozen – with some resemblance to Namacalathus.[2] AffinityAffinity of Melanosclerites is uncertain; algal has been proposed, but hydrozoan (cnidarian)is preferred, but not conclusively established.[1] Melanoscleritoites (Eisenack, 1963) is interpreted as a hydrozoan,[3] with other taxa not attributable to that particular class, on the basis of a broad morphological similarity – though the distinguishing features are far from unequivocal,[1] and the preservation of the material raises some taphonomic problems. The composition resembles that of chitinozoans, scolecodonts, graptolites, and fungi – though a particular species of extant cubomedusan hydroid does produce a similarity resilient "chitinous" 'wall'.[3]OccurrenceThey have been reported in shallow marine sandstones and limestones, as well as upper slope and open marine sediments, in strata from the Lower Cambrian to Upper Devonian.[1] Taxa include:
References1. ^1 2 3 4 {{cite journal|last1=Winchester-Seeto|first1=T.M.|last2=McIlroy|first2=D.|title=Lower Cambrian melanosclerites and foraminiferal linings from the Lontova Formation, St. Petersburg, Russia|journal=Review of Palaeobotany and Palynology|date=May 2006|volume=139|issue=1–4|pages=71–79|doi=10.1016/j.revpalbo.2005.07.012}} {{palaeo-stub}}2. ^{{Cite journal|journal=Comunicações Geológicas |year=2007 |volume=94| pages=93–107 |title=Melanosclerites from the Öjlemyr Cherts, Gotland|author= C. TRAMPISCH}} 3. ^1 {{cite journal|doi=10.2307/1305842|jstor=1305842|title=Melanosclerites: First North American Report of These Problematic Microfossils and Discussion of Their Affinity|author=P. B. Cashman|journal= Journal of Paleontology|volume=66|number= 4|date= July 1992| pages= 563–569 |doi-broken-date=2018-09-21}} 2 : Incertae sedis|Ordovician fossil record |
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