Psammina limbata Kamenskaya, Gooday & Tendal 2015
Creators: name: Holzmann, Maria
name: Barrenechea-Angeles, Inés
name: Lim, Swee-Cheng
name: Pawlowski, Jan
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Chromista
Foraminifera
Monothalamea
Psamminidae
Psammina
Psammina limbata

description: Psammina aff. limbata form 2 sensu Gooday et al., 2018
Supplementary Fig. S7
Psammina aff. limbata form 2. Gooday et al., 2018, 934–935, Fig. 6, Supplementary Fig. S2.
Material examined. Box core 034. Specimen RC1492 (morphology only). Box core 040. Specimen RC1337 (morphology only). Box core 042. Specimen RC1743 (morphology only). Dried.
Description. RC1337 (Supplementary Fig. S7A–C). The test comprises a semicircular, fan-shaped upper part, almost 33 mm wide, merging into a tapered stalk attached to a nodule. The test (stalk plus fan) is around 26 mm high and almost intact apart from some damage to the margin and several holes within the fan. The upper part is distinctly asymmetrical, being better developed on one side than the other. As a result, the stalk is also asymmetrical and longer on the side where the fan is less well developed. The base of the stalk extends into at least three branched root-like structures that spread across the nodule surface. The fan displays clearly developed ‘growth lines’ that delimit concentric zones. The upper part appears to be empty, the lower part is filled with dark material, probably decayed stercomare.
RC1492 (Supplementary Fig. S7D). The upper part of the test is damaged with little or none of the original margin surviving. What remains is 18 mm wide and displays a well-developed concentric zonation. The overall height is also 18 mm. However, the lower part is intact and tapers to a very short (1.2 mm) but relatively wide (3.0 mm) stalk. In addition to the main stalk there is a wide secondary support developed from the base of the fan, and two long, straight, bar-like processes (6.5 and 7.7 mm long and 0.5–0.6 mm wide), arise from the intact margin on the side of the test and are directed obliquely downwards.
RC1743 (dried). The specimen is badly cracked, but basically forms a semicircular fan with a fairly straight lower margin and the base of a stem. It measures 29.3 mm (width) by 25.8 mm (height). The wall has a rough surface with concentric growth zones. It comprises a mesh of sponge spicules, radiolarians and subordinate numbers of agglutinated foraminiferal tests and fragments, mainly yellow or orange in colour. Parts of the test interior are visible through gaps in the cracked wall, revealing parts of several very thin partitions corresponding to the external furrows that define the zones. Otherwise, the interior is empty.
Remarks. These three specimens are very similar to Psammina aff. limbata form 2 from the UK-1 license area, as illustrated in Figs 6E, G of Gooday et al. (2018). The concentric zonation with corresponding internal partitions is a typical feature and distinguishes this form from other stalked Psammina species described by Gooday et al. (2018). The straight, bar-like processes (Supplementary Fig. S7D) are also present in the UK- 1 specimen.
description: Published as part of Holzmann, Maria, Barrenechea-Angeles, Inés, Lim, Swee-Cheng & Pawlowski, Jan, 2024, New xenophyophores (Foraminifera, Monothalamea) from the eastern Clarion-Clipperton Zone (equatorial Pacific), pp. 151-188 in Zootaxa 5419 (2) on pages 177-178, DOI: 10.11646/zootaxa.5419.2.1, http://zenodo.org/record/10792055