Melanosclerite
| Melanosclerite Temporal range:
| |
|---|---|
Scientific 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
[edit]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
[edit]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
[edit]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
[edit]- ^ a b c d e 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. Bibcode:2006RPaPa.139...71W. doi:10.1016/j.revpalbo.2005.07.012.
- ^ C. TRAMPISCH (2007). "Melanosclerites from the Öjlemyr Cherts, Gotland". Comunicações Geológicas. 94: 93–107.
- ^ a b 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. Bibcode:1992JPal...66..563C. doi:10.1017/S0022336000024434. JSTOR 1305842. S2CID 89141723.
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