TERMINOLOGY

Appendix 1 - terms we have not used


The following terms have previously been used in nannoplankton literature but are not used here, for the reasons outlined. In these notes, the term is briefly defined, using our terminology. Then the reason for our not using it is given (see also the introductory section on the choice of terms).
Attachment surface contact-surface between two elements. Superfluous synonym, contact-surface seems more objective.
Bar / Bridge
(sensu Theodoridis 1984)
synonyms of disjunct and conjunct bar, especially for helicoliths. We consider these terms confusing. Also they are of limited application, whereas the terms disjunct and conjunct can be applied to any central-area structure, not just bars.
Bar / Bridge
(sensu Aubry 1988)
as per Theodoridis (1984) but with opposite meanings.
Coccocylinder cylindrical coccosphere. Superfluous term (despite being based on a very beautiful specimen), numerous coccospheres are aspherical and there is no utility in coining numerous shape related terms. {Covington 1985}
Column often used as a synonym of spine, which we prefer.
Cone alternative to apical cycle, for fasciculiths. This cycle only forms a conical structure in a few species so we prefer the more neutral term apical cycle.
Complete/incomplete caneoliths endothecal coccoliths of Syracosphaera with, respectively, 3 and 2 flanges. The distinction is useful but there is no real need for these rather obscure special terms. Also, we prefer to use the terms complete and incomplete to describe degree of completion of growth of coccoliths.{Halldal and Markali 1955}
Cribrate central area obscure alternative to net.
Discolith this term has been widely used for coccoliths with elevated rims but no shields, i.e. muroliths as defined here. We prefer murolith since Discolith has also been used with the different sense of 'a coccolith belonging to the Pontosphaeraceae'. In addition the word discolith is potentially misleading.
Geometric unsuitable alternative of polygonal. Ellipses and circles are just as geometric as triangles or pentagons are.
Heliolith / Ortholith These terms for coccolith types were originally defined on the basis of the crystallographic orientation of the main elements: Ortholiths - dominant elements large with vertical or tangential c-axis orientation (e.g. Discoaster, Braarudosphaera); Helioliths - dominant elements have approximately radial c-axes giving a "sphérolithique" appearance (e.g. Watznaueria, Reticulofenestra). This concept is of limited use since most heterococcoliths are composed of both vertical and radial crystal-units, whilst for many nannoliths the concept of radial and vertical are unclear. As a result there has been only limited agreement between authors who have used these terms as to which taxa should be included in which group - compare Deflandre (1952), Tappan (1980), Aubry (1984 et seq.). {Deflandre 1950}
Jugum synonym of bar. Obscure and superfluous.
Knob synonym of boss, especially for discoasters. We prefer boss, and it has more general application.
Labiatiform elongate double-lipped sacculiform protrusion. Unnecessarily specialised term, applying to only one taxon Algirosphaera robusta.{Halldal and Markali 1955}
Limb / spoke synonym of arm. We prefer arm and it has been more widely applied.
Loxolith rim synonym of zeugoid rim, which we prefer.
Marginal area rim. We prefer rim since it is handier for forming complex terms (e.g. proximal rim element), and because marginal area suggests an unimportant feature whereas this is the most important part of many coccoliths. {many authors}
Nanofossil, Nanoplankton synonyms of nannofossil and nannoplankton. Both nano- and nanno- are etymologically valid prefixes derived from the Greek word nanos (dwarf). We prefer nanno- on the following grounds. A. General usage, as noted by the Oxford English Dictionary (2nd edn 1989), nearly all palaeontologists use nannofossil and many biologists use nannoplankton so this is the de facto "correct" spelling. B. Priority, this was the spelling adopted by Lohmann (1909), when he coined the term nannoplankton. C. Differentiation, the SI use of nano- implies 10-9 (e.g. nanometre).
Optically continuous/
discontinuous structure
essentially synonyms of conjunct and disjunct. We prefer the latter as they are shorter and less potentially misleading.
Oval, ovoid often used as synonyms of elliptical, but these terms more accurately mean egg-shaped and so are very rarely applicable to coccoliths.
Pterygal, meta-pterygal,
pre-pterygal, anti-pterygal
orientation terms for helicoliths. Elegant but too obscure for practical use. {Theodoridis 1984}
Precession alternative to obliquity for description of element orientation in plan view. The common scientific use of precession is related to orbital motions which are not analogous to the element orientation. Hence the special use of this term for coccoliths is obscure. {Black 1972}
Prymnesiophyte alternative to Haptophyte. Green and Jordan (1994) showed that Haptophyta, rather than Prymnesiophyta is the correct division level name, it follows that haptophyte is preferable to prymnesiophyte as the informal name for members of the division.
Rhombolith synonym of scapholith. Both are often used, we follow Braarud et al. (1955a, 1955b) in using scapholith. {Halldal 1954}
Stomatal opening,
stomatal coccolith
circum-flagellar coccoliths. Stomata implies mouth, and so has unwanted functional implications. {Halldal and Markali 1955}
Wedge element of a nannoconid. Bronnimann also used the term plate and this is preferred since it better describes the shape of nannoconid elements as shown by electron microscopy. {Bronnimann 1955}
Zygodiscid rim synonym of zeugoid rim, which we prefer.

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