Tendalia, 2018

Gooday, Andrew J., Holzmann, Maria, Goineau, Aurélie, Pearce, Richard B., Voltski, Ivan, Weber, Alexandra A. - T. & Pawlowski, Jan, 2018, Five new species and two new genera of xenophyophores (Foraminifera: Rhizaria) from part of the abyssal equatorial Pacific licensed for polymetallic nodule exploration, Zoological Journal of the Linnean Society 183, pp. 723-748 : 738

TENDALIA GOODAY & HOLZMANN GEN. NOV.

urn:lsid:zoobank.org:act:D45EFBB7-4629-449C-8326-FA476C7B14B8

Diagnosis: Test free, forming network of fragile agglutinated tubes lying in single plane with open spaces typically 3–5 mm in maximum dimension. Xenophyae comprising mainly radiolarian and diatom fragments on test exterior with smaller mineral grains forming relatively smooth inner surface without ridges. No internal xenophyae. Test interior occupied by 1–2 stercomare branches and a single pale granellare strand.

Etymology: Named in honour of Ole Secher Tendal, whose landmark 1972 monograph and subsequent publications rescued xenophyophores from obscurity and led directly to our present appreciation of their importance in deep-sea benthic communities.

Remarks: Tubular pieces of the test of Tendalia resemble fragments of the genus Syringammina , which Tendal (1972: 34) described as being ‘made of numerous radiating tubes that are connected by side branches’. The new genus is very fragile and known only from fragments in which the tubes lie in a single plane. Since the fragments originate from two cores and were only discovered when the sediment was sieved, complete tests probably form a single layer that spreads across the sediment, probably just below the surface. Syringammina , on the other hand, has a large (often 5 cm or more in diameter) three-dimensional, typically dome-shaped test that is often clearly visible on the sediment surface in seafloor photographs ( Tendal & Lewis, 1978; Bett, 2001). There are no molecular data for the type species ( S. fragilissima Brady, 1881 ), but DNA sequences obtained from S. corbicula ( Pawlowski et al., 2003) , which is morphologically similar to S. fragilissima , suggest that Syringammina and Tendalia are not closely related ( Fig. 3).

Tendalia fragments could be confused with those of Occultammina , a genus represented by a single described species ( Tendal, Swinbanks & Shirayama, 1982) and several records of undescribed species, including from the eastern CCZ ( Gooday et al., 2017a). The main morphological differences are that Occultammina tubes branch but unlike those of Tendalia they do not anastomose, and they possess distinct inner and outer test layers (the former thicker than the latter) as well as several ridges running longitudinally along the inner surface of the wall ( Tendal et al., 1982; Gooday et al., 2017a: fig. S7e–g). Although different kinds of agglutinated grains are visible on the inner and outer surfaces of the test in the new genus, they are not differentiated into two distinct layers. Unfortunately, no DNA data are available for Occultammina .

TENDALIA RETEFORMIS GOODAY & HOLZMANN GEN.