Radiella pumix Ekins & Erpenbeck & Wörheide & Hooper 2023, sp. nov.
Creators: name: Ekins, Merrick
name: Erpenbeck, Dirk
name: Wörheide, Gert
name: Hooper, John N. A.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Porifera
Demospongiae
Polymastiida
Polymastiidae
Radiella
Radiella pumix

description: Radiella pumix sp. nov. Ekins, Erpenbeck & Hooper
urn:lsid:zoobank.org:act: E596A9A5-C755-4561-BC2C-A16A6EA21316
Figures 1, 2 & 4, Tables 2 & 3
Part Radiella irregularis Ridley & Dendy, 1886, sensu O’Hara et al. 2020: 4
Type material: Holotype QM G337516, Off Byron Bay, New South Wales, Australia, -28.6765, 154.20327 to - 28.709, 154.1897, 2587– 2562 m, Beam Trawl, Coll. Merrick Ekins on RV Investigator, Cruise IN2017_ V03, Sample 90-202, 7/VI/2017.
Paratypes: QM G337515 same collection details as QM G337516, Sample 90-180; QM G337616 same collection details as QM G337516, Sample 90-169; QM G339368 same collection details as QM G337516, Sample 90-169.3.
Etymology: named for its substratum, pumix L., pumice.
Diagnosis: Radiella species attached to pumice, lacking an obvious fringe, but expands by having new discrete hemispherical bouquets outside the ectosome.
Morphology: A convex cream coloured sponge attached to drowned pumice stone (Fig. 4 A, B). The holotype QM G337516, is 8.3 mm in diameter, and 1.2 mm in height. The paratype QM G337616, is 6 mm in diameter and only 0.83 mm in height, whilst paratype, QM G337515 is 5.8 mm in diameter and 1.4 mm in height. The upper surface is hispid, and the sponge lacks an obvious fringe (Fig. 4 C-E). The holotype has a single central papilla, the papillae could not be obviously seen on most of the paratypes (Fig. 4 E).
Skeleton: The choanosomal skeleton is composed of confusedly arranged small tylostyles (Fig. 4 E). The ectosome consists of bouquets of the large principal tylostyles, many of which originate from the choanosome. These bouquets of the principal tylostyles also line the central oscular canal. The ectosome and the periphery of the specimen are characterised by the appearance of discrete bouquets (Fig. 4 C, D). In some cases, the bouquets on the surface appear as spheres giving the surface a papillate appearance.
Spicules: The principal tylostyles vary greatly in length and may be possibly divided into two size categories with large overlapping sizes (640–2270 × 7–19 μm) (Tab. 2). There are smaller tylostyles arranged in disorder in the choanosome (100–300 × 3–15 μm) and intermediate tylostyles (339–660 × 5–13 μm) composing the bouquets of the main ectosomal skeleton.
Distribution: Northern New South Wales, Australia, abyssal depth.
Ecology: Found exclusively on submerged pumice stones.
Molecular data: 28S-C region barcode of holotype QM G337516 (ENA Accession number OY741336), paratype QM G337616 (ENA Accession number OY741340), forming a distinct and supported clade (Figure 2).
Remarks: The new species resembles Spinularia australis Lévi, 1993 from bathyal depths off New Caledonia by the body shape and size and the substrate it grows on, the pumice stones. The individuals of S. australis are slightly larger in diameter, 7 to 12 mm, but similar in height, 1.4 to 3.7 mm. However, our new cream-coloured species differs from S. australis by lacking the lower fringe and associated large tylostyles, with the largest difference being the ectosomal skeleton with many independent small plumose bouquets which is the most distinctive character of this new species. The new species also lacks the radial skeleton seen in S. australis, and it also differs importantly from S. australis by having a new category of much smaller tylostyles and it also lacks raphides. These specimens were previously listed as Radiella irregularis in O’Hara et al. (2020).
description: Published as part of Ekins, Merrick, Erpenbeck, Dirk, Wörheide, Gert & Hooper, John N. A., 2023, Deep Water Polymastiidae (Porifera, Polymastiida) from the South West Pacific, pp. 57-88 in Zootaxa 5369 (1) on pages 63-65, DOI: 10.11646/zootaxa.5369.1.3, http://zenodo.org/record/10146837