TERMINOLOGY

2. Coccosphere related terms


These terms cover coccosphere shape, description of the variation of coccoliths on a coccosphere, and their arrangement on the coccosphere. Much of the teromology is based on Okada and McIntyre (1977).

2.1 Descriptive Terms

Monomorphic all coccoliths of similar type (e.g. Coccolithus).
Dimorphic coccoliths of two discrete types (e.g. Scyphosphaera).
Polymorphic coccoliths of more than two discrete types (e.g. Syracosphaera pulchra).
Varimorphic coccosphere with coccoliths whose size and/or morphology varies according to position on the coccosphere (e.g. Helicosphaera). {Young et al. 1997}
Dithecate with two discrete layers of coccoliths of different types (e.g. Syracosphaera pulchra).
Endotheca inner layer of coccoliths of dithecate coccosphere.
Exotheca outer layer of coccoliths of dithecate coccosphere.
Monothecate with a single layer of coccoliths (e.g. Scyphosphaera).
Multilayered with two or more layers of coccoliths but no differentiation into endo- and exotheca (e.g. Emiliania, Florisphaera, Coccolithus pelagicus phase hyalinus).
Shape coccospheres are three-dimensional so their shape should be described using appropriate terms for solid objects. Useful terms include: cylindrical, ellipsoidal, fusiform (elongate with tapering ends), obpyriform (inverse pear-shaped), ovoid (egg-shaped, i.e. one end broader than the other), spherical. See also Heimdal (1993), Jordan et al. (1995).

coccosphere features
coccosphere shape
Coccosphere shape (see also Heimdal 1993).

2.2 Orientation

Apical pole end of coccosphere with flagellar opening.
Antapical pole opposite end of coccosphere.
Antapical coccoliths (abb. AAC)
coccoliths occurring at antapical pole.
Body coccoliths (abb. BC)
coccoliths other than polar coccoliths and exothecal coccoliths.
Circum-flagellar coccoliths / apical coccoliths (abb. CFC)
coccoliths occurring around flagellar opening. (Alternative term stomatal coccoliths, see appendix).
Exothecal coccoliths (abb. XC)
coccoliths of the exotheca
Flagellar opening opening in coccosphere through which the flagella and haptonema pass.
Polar coccoliths coccoliths occurring at poles of coccospheres. {Kamptner 1937}

Coccolith arrangement

2.3 Coccolith arrangement

Overlapping adjacent coccoliths overlap.
Non-overlapping adjacent coccoliths arranged with edges directly butting rather than overlapping.
Interlocking adjacent coccoliths interlock.
Non-interlocking adjacent coccoliths do not interlock.
N.B. Interlock and overlap are separate phenomena, and can occur in any combination (see Fig. 1).

2.4 Informal taxon-based terms

As with coccoliths (see below), various terms have been coined to refer to coccospheres of particular taxonomic groups. These do not need any special definition, beyond noting the taxonomic groups included. E.g.; braarudosphere Braarudosphaeraceae, helicosphere Helicosphaeraceae.


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