Geology Reference
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von Saccocoma -Resten (Schwebcrinoiden) in Oberjura-
Kalken des nördlichen Tethys-Schelfs. - Geologische
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Kristan-Tollmann, E. (1977): Zur Gattungsunterscheidung
und Rekonstruktion der triadischen Schwebcrinoiden. -
Paläontologische Zeitschrift, 51 , 195-198
Moffat, H.A., Bottjer, D.J. (1999): Echinoid concentration
beds: two examples from the stratigraphic spectrum. -
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Moore, R.C. (ed., 1967): Echinodermata 1. General charac-
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Moore, R.C., Jeffords, R.M. (1968): Classification and no-
menclature of fossil crinoids based on dissociated parts of
their columns. - University of Kansas Paleontological Con-
tributions, 9 , 1-86
Moore, R.C., Teichert, C. (eds., 1978): Echinodermata 2.
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Nebelsick, J. (1995): Uses and limitations of actuopaleonto-
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Further reading: K128
or solid (cidaroid type). The hollow center is called the
lumen. The solid center filled with stereom is termed
the medulla (Fig. 10.57), the surrounding zone is the
cortex. A still useful classification of echinoid spines
based on the microstructure was established by Hesse
(1900) who distinguished six major groups (see Pl. 96/
6-8, 12, 13 for examples).
Distribution: The oldest echinoids appeared in the
Late Ordovician but were only a minor element of the
benthos throughout the Paleozoic. The roots of mod-
ern echinoids can be traced back to the Permian where
the first cidaroids appeared and started to diversify in
the Triassic. A major diversification of echinoids took
place in the Jurassic. The first irregular echinoids spe-
cialized in deposit feeding appeared in the Jurassic.
Echinoids generally became a major constituent of the
shallow-water benthos during the Jurassic and Creta-
ceous, also in deep-water environments (chalk) in the
Late Cretaceous.
Ophiuroidea and Holothuroidea
Remains of echinoderm groups other than crinoids
and echinoids are extremely rare in thin sections of
limestones, although skeletal elements of holothurians
and ophiuroids are often abundant in acid residues of
carbonates.
Cross sections of ophiuroid vertebrae from Meso-
zoic and Late Tertiary limestones exhibit two coalesced
calcite plates, each of which constitutes a single crys-
tal, forming a mirrowed reflection pattern (Glazek and
Radwanski 1968).
Holothurian sclerites may be represented in thin sec-
tions by wheel-like structures (Fig. 10.58; Pl. 96/4) or
sieve plates.
Basics: Echinoderms
Donovan, S.K. (1991): The taphonomy of echinoderms;
calcareous multi-element skeletons in the marine environ-
ment. - In: Donovan, S.K. (ed.): The process of fossil-
ization. - 241-269, London (Belhaven Press)
Glazek, J., Radwanski, A. (1968): Determination of brittle
star vertebrae in thin sections. - Bulletin de l'Académie
polonaise des Sciences, Série des Sciences géologique
et géographique, 16 , 91-96
Guensburg, T.E., Sprinkle, J. (1992): Rise of echinoderms in
the Paleozoic evolutionary fauna: significance of paleo-
environmental controls. - Geology, 20 , 407-410
Hess, H., Ausich, W.E., Brett, C.E., Simms, M.J. (1999): Fos-
sil crinoids. - 275 pp., Cambridge (University Press)
Hesse, W. (1900): Die Mikrostruktur der fossilen Echinoi-
deenstacheln und deren systematische Bedeutung. - Neues
Jahrbuch für Mineralogie, Geologie und Paläontologie,
Abhandlungen, 13 , 185-264
10.2.5 Rare Thin-Section Fossils
In contrast to the preceding chapters, this chapter and
plate 97 deal with fossils that may be recognized in
thin sections of limestones, but are generally rare.
Vertebrate remains seen in thin-sections are pre-
dominantly bones, scales and teeth of fish. Bones may
have ovate, rectangular or round shapes. Remains of
amphibians and reptiles are very rare but may occur in
lacustrine carbonates. These phosphatic vertebrate
grains display clear, amber or brownish, sometimes
black colors in thin sections under ordinary light. Be-
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