Nannotax3 - ntax_Farinacci - Chrysochromulina latilepis

Original descriptions of taxa. For coccolithophores, and many calcispheres, these are pages from the Farinacci & Howe Catalog of Calcareous Nannofossils. In other cases (e.g. non-calcifying haptophytes) the data is directly compiled on this site. The "Catalogue of Calcareous Nannofossils" was originally compiled by Prof A. Farinacci 1969-1989, since 2000 it has been updated and extended by Richard Howe - see The Farinacci and Howe Catalog - an Introduction.
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Citation: Chrysochromulina latilepis Manton 1982

Type sample (& lithostrat): collected from the ferry between Baltra and Santa Cruz by dipping near,the Baltra shore on 15 August 1977, sea temperature 23 °C.

Standardised type level: 160_HOLOCENE

Type locality: Galapagos lands, E. Pacific

Farinacci catalog page (& compiler): n/a

Current citation: Chrysochromulina latilepis Manton 1982

Protoplast ovoid to spheroidal, c. 6 x 9 μm, with somewhat unequal flagella, the longer up to 20 μm and the shorter up to 50% less; the haptonema long, coiling when retracted into a helix of not less than 20 gyres c. 1 μm diam. Periplast dimorphic, the outer layer composed of large, c. 3 x 2.5 μm, flat, very thin oval plates, each with a threadlike marginal thickening projecting slightly from the distal face and with a delicately woven surface-patterning dominated by radial ridges arranged in quadrants on the proximal face, but radial ridges on the distal face overlaid by irregular tangential threads partly concealed by amorphousmaterial, especially towards the scale centre. A few, slightly larger but similarly patterned and equally thin, plate-scales acting as base-plates of slender, tapered, spines not more than 6 μm long, each spine subtended at the base by four, equally spaced, thin struts, adnate to the plate surface and extending to the edge. The inner periplast composed of small, 0.7 x 0.5 μm, oval plates, each conspicuously patterned with radial ridges on the proximal face and irregular threads on the distal face; a broad rope-like, erect rim loosely constructed from tangential threads present on the edge of thisface.

Cells 6 x 9 μm; outer layer scales 3 x 2.5 μm, flat, very thin oval plates, a few with spines; inner layer 0.7 x 0.5 μm, oval plates.

Use of the phrase "delicately woven" in the description of scale patterning should be understood here s denot- ing conformity with recent advances in knowledge of other taxa and not s a record of a new departure limited to this species. In the special case of C tenuispina Manton an exceptionally favourable species for visual analysis of the type required, attention was drawn (Manton 1978b) to the existence of a layered substructure located within the scale and underlying, on each face, the patterning on the surface itself. Parts of an equivalent substructure can be seen in C. latilepis by close scrutiny of the most highly magnified scales. In a fleld such as that illustrated in Figure 4, the familiar pattern of radial ridges arranged in quadrants dominates all scales exposed with their lower (proximal) face uppermost, but when seen more highly magnified, as in Figure 6 centre right, especially where the direction of shadowing is favourable, a compact layer of tangentially wound threads is clearly evident between the radial ridges but bonded to them. Equivalent analysis of the distal face is here impeded by the amorphous deposit concealing details of this surface (Fig. 6 centre left), but as we shall see later, a sub-structure of the same general type is widespread and is undoubtedly to be found in many other species within the genus Chrysochromulina though not, perhaps, all. Hence the desirability of taking explicit note of its presence, in formal descriptions, whenever the facts can be ascertained.

An important detail, excluded from the formal description from lack of sufficient evidence is that of the precise distribution of spines on the cell s a whole. These are relatively few, not more than 6 being visibly associated with each of the illustrated specimens (Figs. l , 2), but whether, in life, the spines would have been loosely scattered over the periplast or grouped at one or both poles is still uncertain.

References:

Manton, I. (1982). Chrysochromulina latilepis sp. nov. (Prymnesiophyceae = Haptophyceae) from the Galapagos Islands with preliminary comparisons with relevant taxa from South Africa. Botanica Marina. 25: 163-169. gs

CATALOG - Chrysochromulina latilepis

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