Catalog - Textularia variabilis Catalog - Textularia variabilis

CATALOG OF ORIGINAL DESCRIPTIONS: Textularia variabilis Williamson 1858

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.

Higher levels: pf_cat -> T -> Textularia -> Textularia variabilis
Other pages this level: T. biarritzensis, T. costata, T. decurrens, T. globulosa, T. martini, T. striata, T. variabilis

Textularia variabilis

Citation: Textularia variabilis Williamson 1858
taxonomic rank: species
Described on page(s) : 76
Type specimens: figs 162, 163

Current identification/main database link: Bolivina variabilis (Williamson 1858)

Original Description

Shell oblong; sub-compressed; with rounded and crenulated margins. Segments more or less turgid of nearly equal length and breadth. Septal lines depressed sometimes straight, but more frequently a little arcuate, and bending towards the primordial segment those of one longitudinal series of segments opposed to the centres of the segments in the other series, producing a longitudinal zigzag line in each peripheral aspect, sometimes excavated into a deep and conspicuous groove with prominent margins. Septal orifice conspicuous; at the umbilical border of each segment, close to the preceding one. Texture hyaline, or sub-hyaline conspicuously foraminated; foramina sometimes placed at the bottom of deep hexagonal pits, which render the shell rugose and semi-opaque. Hue a dirty white.

Length 1/45 inch (=50 µm)

Extra details from original publication
Locations Torquay ; Mrs. Brett. Arran, Skye, Fowey, Shetland, Brixham ; Mr. George Barlee. Whitehaven Rev. Mr. Chalmers. Exmouth Mr. W. Kane. Plymouth Sound and Eddystone; Mr. Spence Bate. Boston, Levant, Dardanelles.

Editors' Notes
Williamson (1858) described the typical form and three varieties (spathulata, difformis and laevigata). The description quoted here is that of the typical form - his Textularia variabilis typica [editor's comment - JRY 2022]

No type appears to have been designated, but the species was described from recent sediments off the British Isles, indicating that the name should be associated with an extant species, and the species concept has remained stable ever since. Designation of a type would require a thorough revision of species concepts invoked for material derived from the plankton, combined with the evaluation of other morphologically similar species described from the benthos. [Brummer & Kucera 2022]


Brummer, G-J. A. & Kucera, M. (2022). Taxonomic review of living planktonic foraminifera. Journal of Micropalaeontology. 41: 29-74. gs

Williamson, W. C. (1858). On the recent foraminifera of Great Britain. The Ray Society, London. 1-107. gs O


Textularia variabilis compiled by the pforams@mikrotax project team viewed: 18-4-2024

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