Gromia WINNETOUI 2009, SP. NOV.

GROMIA WINNETOUI SP. NOV. (FIGS 7–9)

Diagnosis: Species of Gromia varying from sausageshaped, to elongate oval, or more irregular in shape. Length 1.0– 2.8 mm; width 0.3–0.8 mm; length: width ratio 1.8–8.9. Single, conical oral capsule. Test typically enclosed completely or partially in a coarsely agglutinated case.

Type material and locality: The holotype and paratypes are from an AGT deployment at station 121#7, 63°34.92 ′ S, 50°41.97 ′ W, 2630-m depth, 14th March 2005. They are deposited at the Research Institute and Natural History Museum Senckenberg, Frankfurt am Main. The holotype is catalogued under reg. no. SMF XXVII 7402. The paratypes are catalogued under reg. no. SMF XXVII 7403. The type specimens are preserved in 4% buffered formaldehyde solution.

Additional material: Station 121#7; 36 specimens.

Derivation of name: From Winnetou, the Native American hero of several novels written by Karl May, and a personal hero of two of the authors.

Overall appearance: The organic test varies from sausage-shaped, to elongate oval, to irregularly shaped (Fig. 7A–D), and is dark to light brown in colour. specimens range in length from 1.0 to 2.8 mm (mean 1.9 ± 0.5 mm), and in width from 0.3 to 0.8 mm (mean 0.5 ± 0.1 mm). The length: width ratio varies from 1.8 to 8.9 (mean 3.9 ± 1.6). Many specimens are encased completely or partially in a coarsely agglutinated case, which is whitish or light brown in colour (Fig. 7A). The case is composed of fairly large, loosely cemented mineral particles, mainly quartz, but also including some dark grains, giving it a speckled appearance (Figs 7A, 8A). Fine clay particles are also present, particularly on the inside of the case, where they form a cushion between the quartz grains and the organic test wall (Fig. 8B–D).

Oral capsule: The single oral capsule is relatively small, and is often obscured by the agglutinated test (Fig. 7A). Where visible, it protrudes as a conical structure in lateral view, and ranges in height from 80 to 120 Mm (N = 4), and in width from 40 to 80 Mm (N = 4) (Fig. 7C, D). The central canal is sometimes visible.

Test wall: Where the wall is visible, it appears dented as a result of pressure from the overlying agglutinated grains. SEM photographs reveal pores ranging in diameter from 10 to 50 nm, scattered across the test surface (Fig. 8D). Clay particles (~ 200 nm in diameter), presumably derived from the outer case, are partially embedded in the wall surface (Fig. 8D). TEM images revealed multiple layers of honeycomb membranes constituting the inner part of the wall. They appear as regular lines (Fig. 9A–D).

Test contents: The test contents consist of a more or less densely packed mass of light-brown stercomata.

Distribution: Powell Basin, east of the tip of the Antarctic Peninsula, ~2600-m depth (Fig. 1).

Remarks: Gromia winnetoui sp. nov. can be distinguished from all previously described gromiids by the agglutinated case that encloses the organic test. This structure resembles the agglutinated capsule that surrounds some allogromiid-like organisms from near-shore habitats in the Antarctic and the Arctic (Gooday et al., 1996, 2005; Gooday, 2002). It also differs from both G. marmorea sp. nov. and G. melinus sp. nov. in having a more elongate shape.