Nannotax3 - ntax_Farinacci - Scrippsiella triquetracapitata

CATALOG - Scrippsiella triquetracapitata


Folder trail: ntax_Farinacci -> Calcispheres -> Scrippsiella -> Scrippsiella triquetracapitata
Folders this level: S. sweeneyi, S. triquetracapitata

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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Current identification/main database link: Scrippsiella triquetracapitata Meier, Janofske, & Willems 2002

Compiled data

Citation: Scrippsiella triquetracapitata Meier, Janofske & Willems  2002
Rank: Species
Language: EN
Described on page(s) : 612-3
Type specimens: Holotype: Cyst no. SM SIV/7, SEM micrographs 10303, 10295 (Fig. 9, a–b), now cut in thin sections on slides SIV 14-17, inventory number GSUB M 19
Type sample (& lithostrat): Sample no. 69 - surface sediment, 2155m deep
Type age (chronostrat): Extant
Standardised type level: 160_HOLOCENE
Type locality: E. Mediterranean; Western Levantine Sea, 33.87N; 24.87E
Type repository: Bremen; Geosciences Collection of the University of Bremen
Repository Country: Germany
Farinacci catalog page (& compiler): n/a
Current citation: Scrippsiella triquetracapitata Meier, Janofske, & Willems 2002


Original Description

Diagnosis: Cysts are ellipsoid and formed by a single calcareous layer. The wall consists of subtriangular crystal units, from each of which a short triangular pyramidal spine emerges that ends in an isosceles triangular, pyramidal tip. The crystallographic c-axis of the crystals is oriented tangentially to the cyst wall.

Description: Scrippsiella triquetracapitata is a relatively large cyst with a length of 30–43.5 µm and a width of 21–38.8 µm (n = 5). The wall consists of a single layer of crystals with a thickness of about 2 µm. The main morphological feature of this species is its crystal form, showing a subisosceles triangular outline (Fig. 9, a–e). From each basal plate, which has a width of about 5 µm, a short pyramidal spine arises (about 2.5 µm long), which is tipped distally by an isosceles triangular pyramid. The edges of the triangles and pyramids are always rounded and the sides can be slightly concave, giving the units a triradiate character (Fig. 9b). An undamaged archeopyle has not been observed, but generally the operculum seems to include apical and intercalary plates (Fig. 9e). Cysts can be easily identified in LM studies by their triangular capitate spines, each of which appears in a monochrome color in polarized light using a gypsum plate. In thin sections the spines appear as monocrystalline units with their c-axis oriented tangentially to the cyst wall (Fig. 8).

Size:
length 30–45 µm; width 20–40µm

Etymology:
Latin: triquetrus

Extra details from original publication
Discussion. One cyst of S. triquetracapitata has been described as Rhabdothorax sp. by Keupp and Versteegh (1989) from the Quaternary of Southern Crete. The not validly published genus Rhabdothorax Kamptner ex Gaarder (Williams et al. 1998) is a synonym of Scrippsiella, and the species originally allocated to Rhabdothorax have been transferred to Scrippsiella (Janofske 2000). Scrippsiella triquetracapitata is similar to the ellipsoidal spiny cysts of Scrippsiella trochoidea but can be distinguished by its larger and morphologically different spines, which are triangular in cross-section, more compact, and always have a characteristic pyramidal tip. This species was assigned to the genus Scrippsiella due to the tangential ultrastructure and the presumably large and angular archeopyle. The emended diagnosis of Janofske (2000) for the genus Scrippsiella states that the operculum includes the plates 2'–4' and 1a–3a. We found only one specimen with an archeopyle-like structure, which is large and seems to include the 2'–4' and 1a–3a plates, and further investigations are necessary for confirmation.

Editors' Notes

References:

Meier, K. J. S., Janofske, D. & Willems, H. (2002). New calcareous dinoflagellates (Calciodinelloideae) from the Mediterranean Sea. Journal of Phycology. 38: 602-615. gs


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Scrippsiella triquetracapitata: Catalog entry compiled by Jeremy Young. Viewed: 29-11-2022

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Link to WoRMS (World Register of Marine Species)

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