Melanosclerite
Temporal range:
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Cnidaria (?)
Order: †Melanoscleritoitidea
Eisenack, 1963
Family: †Melanoscleritoitidae
Eisenack, 1942

The Melanosclerites are a group of problematic microfossils obtained by palynological processing.

Morphology

The 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]

Affinity

The affinity of melanosclerites is uncertain; algal has been proposed, but hydrozoan (cnidarian) is preferred, though 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 at least one species of extant cubomedusan hydroid does produce a similarity resilient "chitinous" 'wall'.[3]

Occurrence

They 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:

  • Eichbaumia Schallreuter, 1981
    • Eichbaumia incus Schallreuter, 1981
  • Melanoarbustum Górka, 1971
    • Melanoarbustum balticum Górka, 1971
  • Melanoclava Eisenack, 1942
    • Melanoclava betaotda Eisenack, 1942
  • Melanocyathus Eisenack, 1942
    • Melanocyathus dentatus Eisenack, 1942
  • Melanoporella Górka, 1971
    • Melanoporella polonica Górka, 1971
    • Melanoporella bulla
    • Melanoporella clava Schallreuter, 1981
  • Melanorhachis Eisenack, 1942
    • Melanorhachis regularis Eisenack, 1942
  • Melanoscleritoites Eisenack, 1963
  • Melanosteus Eisenack, 1942
    • Melanosteus acutus Eisenack, 1942
  • Melanostylus Eisenack, 1963
    • Melanostylus coronifer Eisenack, 1963
  • Menola Schallreuter, 1981
    • Menola os Schallreuter, 1981
  • Mirachitina Eisenack, 1963
    • Mirachitina quadrupedis Eisenack, 1963
  • Semenola Schallreuter, 1981
    • Semenola semen Schallreuter, 1981

References

  1. 1 2 3 4 5 Winchester-Seeto, T.M.; McIlroy, D. (May 2006). "Lower Cambrian melanosclerites and foraminiferal linings from the Lontova Formation, St. Petersburg, Russia". Review of Palaeobotany and Palynology. 139 (1–4): 71–79. doi:10.1016/j.revpalbo.2005.07.012.
  2. ↑ C. TRAMPISCH (2007). "Melanosclerites from the Öjlemyr Cherts, Gotland". Comunicações Geológicas. 94: 93–107.
  3. 1 2 P. B. Cashman (July 1992). "Melanosclerites: First North American report of these problematic microfossils and discussion of their affinity". Journal of Paleontology. 66 (4): 563–569. doi:10.1017/S0022336000024434. JSTOR 1305842. S2CID 89141723.


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