Abyssalia foliformis Gooday and Holzmann 2020

Holzmann, Maria, Barrenechea-Angeles, Inés, Lim, Swee-Cheng & Pawlowski, Jan, 2024, New xenophyophores (Foraminifera, Monothalamea) from the eastern Clarion-Clipperton Zone (equatorial Pacific), Zootaxa 5419 (2), pp. 151-188 : 162-163

Abyssalia foliformis Gooday and Holzmann 2020

Fig. 5

Abyssalia foliformis Gooday and Holzmann 2020, pp. 15-18 , Figs 9 , 10

Material examined. BC015 RC0612 (morphology and genetics). Sequenced isolate: 21442

Description. Shipboard photographs show a test fragment attached to a nodule ( Fig. 5A ). The fragment was detached when seen later in the laboratory ( Fig. 5B ). It is plate-like, about 21 mm long and 2.0– 2.6 mm thick with a slight twist and widening from about 7.0 mm near the base to about 13 mm at its upper end. The agglutinated particles consist almost entirely of sponge spicules, apart from one or two agglutinated foraminifera. A felted mesh of these spicules forms a poorly defined surface layer from which some of them project. This layer merges into a more open framework of spicules occupying the test interior.

The stercomare, which comprises small, rounded pellet-like masses ( Fig. 5F ), originally occupied much of the test interior. However, they are quite loose, and many had fallen out from the central part of the fragment following preservation. In peripheral areas, however, the stercomare is denser and has largely retained its coherence ( Fig. 5B ), Here, it appears to consist of tightly packed pellets that are presumably bound together in some way.

Branched granellare strands are well-developed and pervade much of the test interior ( Fig. 5C, D ). They are pale cream and of variable width (34–140 µm), often with more or less bulbous sections. The organic tubes that enclose the cytoplasmic branches are relatively thick and clearly visible under a stereomicroscope, given suitable lighting. The tubes are closely associated with the internal spicules, to which they are attached at multiple points ( Fig. 5E ).

Remarks. The holotype and hitherto unique specimen of Abyssalia foliformis from the western CCZ (Gooday et al., 2020) was attached to a nodule by a stalk that merged gradually with the wider upper part of the test. Our new specimen includes only the stalk, but the shape is consistent with the morphology of the holotype. Other features, notably the use of spicules in test construction, the pellet-like stercomare and the granellare strands with their well-developed organic tubes attachment to spicules, are very similar to those described for A. foliformis . We are therefore confident that this fragment represents the same species as that described by Gooday et al. (2020). The only apparent difference is that the holotype has a homogenous test that lacks a surface layer, whereas there is some differentiation between the outer and inner parts of our fragment. This is possibly because the original description was based mainly on the upper part of the test whereas we have only the basal stalk.

Gooday and Wawrzyniak-Wydrowska (2023; Fig. 6F, G therein) recently illustrated a xenophyophore fragment from the IOM license area that may have been derived from an Abyssalia species. Unfortunately, granellare from which DNA could potentially be amplified was not present, and not enough of the morphology was preserved to determine whether it could be assigned to A. foliformis .

Figures

FIGURE 5. Abyssalia foliformis Gooday & Holzmann 2020; RC0612 (BC015). A, Shipboard photograph of unique test fragment. B–F, Laboratory photographs of test fragment; the stercomare had been lost from the central part of the fragment. C, D, Details of fragment showing granellare. E, Fragments of cytoplasm detached from test; note that the fragments are partly attached to sponge spicules. F, Loose stercomare pellets that had fallen out of the test.

FIGURE 6. Abyssalia aff. foliformis, shipboard photographs; RC0615 (BC011).A, B, Two different side views. C, Test viewed from above. D–F, Details of test; the yellow tube in E is probably part of a Saccorhiza ramosa test.

FIGURE 9. Claraclippia seminuda Gooday & Holzmann gen. & sp. nov.; holotype, RC0202 (BC005). A, B, Laboratory photographs taken in Geneva; details of test surface showing stercomate branches, reddish granellare strands, and the surface veneer of fine particles, which was then still partially intact. C–F, Laboratory photographs of fragments consisting mainly of stercomare branches; the photographs were taken in Southampton, by which time the surface veneer of fine particles had largely disappeared.

FIGURE 10. Stereodikyoma mollis Gooday & Holzmann gen. & sp. nov. A, B, Holotype, RC1623 (BC039); shipboard photographs of intact specimen attached to nodule. C–F, Paratype, RC1697 (BC040). C, D, Shipboard photographs. E, F, Laboratory photographs (Geneva) of the two largest fragments.