Lycopodina helios, Ekins & Erpenbeck & Hooper, 2020

Ekins, Merrick, Erpenbeck, Dirk & Hooper, John N. A., 2020, Carnivorous sponges from the Australian Bathyal and Abyssal zones collected during the RV Investigator 2017 Expedition, Zootaxa 4774 (1), pp. 1-159 : 144-146

Lycopodina helios sp. nov.

Figure 29 , Table 14

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Material examined: Holotype: QM G337468 , off Cape Barren Island , Flinders Central Marine Reserve , Tasman Sea, NE Tasmania, Australia, Station 16, 40° 27’ 46.8”– 40° 27’ 40.3” S, 149° 24’ 54.0”– 149° 21’ 50.4” E, 4129– 4321 m depth, Brenke Epibenthic Sledge, Coll. Merrick Ekins on RV Investigator, Cruise IN2017_ V03 , Sample 16-140, 21/v/2017.

Etymology: Gr. Helios, the sun refering to the sponges bright radiant morphology

Distribution: This species is currently restricted to Tasmania, Australia, at abyssal depth.

Description:

Growth form: A delicate erect pedunculate sponge with a subspherical club-shaped body and a long slender stem ( Figure 29 G–H). Total length of the sponge is 16.6 mm, the majority of this being the stem of 11.3 mm. The width of the sponge body is 4 mm and diameter of the stem is less than 1 mm. The basal attachment was not collected.

Colour: Yellow on-deck and in ethanol.

Ectosomal skeleton: The remains of a very thin ectosomal membrane bearing the anisochelae can be seen covering the body of the sponge. This membrane is supported by the projecting subtylostyles ( Figure 29 I ).

Endosomal skeleton: The axis of the stem is cored by dense longitudinally arranged subtylostyles ( Figure 29 J ). The body has subtylostyles radiating in every direction, with the longer of these projecting through the membranous ectosome. Adjacent radiating subtylostyles often cluster together to form filaments covered in anisochelae ( Figure 29 I ).

Megascleres: Subtylostyles with long tapering points and narrowed or slightly subtylote bases, with the largest diameter of styles approximately at their centre. However, there is no clear size delineation of the megascleres, (508-(849)- 1770 x 8.2-(13.1)-18.9 μm, n=63) ( Figure 29 B–E).

Microscleres: Palmate anisochelae with three smooth upper alae, the central one nearly fully detached, and the two lateral ones fused to the fimbria. The lower frontal alae has three terminal spines and the lower lateral alae each have two spines. Anisochelae length (15.5-(21.4)-25.5 μm x 4.5-(7.1)-9.4 μm (large alae width), 3.3-(5.2)-6.7 μm (small alae width) ( Figure 29 A ). Sigmancistras were also found (12.2-(16.0)-18.5 x 1.0-(1.4)-2.3 μm, n=46) ( Figure 29 F ).

Molecular data: The 28S sequence of QM G337468 is provided in the Sponge Barcoding Database under accession number SBD#2306 and the molecular difference to other congenerics displayed in Figure 3 .

Remarks: This new species of Lycopodina has a more spherical shaped body of a much smaller size than its most similar species, L. callithrix ( Hentschel, 1914) . In addition this species differs in the shape of the anisochelae, which are much larger than those of L. callithrix reported by Hentschel (1912) and Koltun (1964). This species also lacks the very large styles/ subtylostyles (2000–4000 µm) that are present in L. callithrix . This species is also unique in having the ectosomal membrane containing the anisochelae supported by the subtylostyles ( Figure 29 I ).

This new species shares a similar morphology size and shape as L. callithrix reported by Dressler-Allame et al. (2017), as well as anisochelae (9–22 x 4–9 µm) and style/subtylostyle (180– 1600 x 7–18 µm) measurements. Possibly some or all of the specimens of L. callithrix reported by Dressler-Allame et al. (2017) could belong to this new species. Molecular techniques may in the future confirm if they are conspecific.

The description of L. communis ( Lopes & Hajdu, 2014) from the Campos Basin off Brazil is also very similar to that of L. callithrix , both sharing a similar gross morphology, the size and dentition of the anisochelae, and the size range of mycalostyles falling within the size range of the specimens described by Dressler-Allame et al. (2017). Molecular techniques may in the future confirm whether or not they might be conspecific, despite their very disjunct biogeographic ranges.

Figures

FIGURE 3. Maximum-likelihood phylogram of the DNA sequences of this study in comparison with other, published cornivorous sponges. Sequences from taxa of this study are in bold. Number at the branches are RAxML rapid bootstrap values. Numbers following the taxa are either QM registration numbers (QM G3xxxxx) or NCBI Genbank accession numbers. Scale bare are substitutions per site. Please note that the reconstruction does not represent a phylogeny as due to the variability of the 28SrRNA gene C-Region barcoding marker no unambiguous alignment is possible and clipping ambiguous sites would remove diagnostic characters for taxon distinction. The tree therefore indicates molecular differences rather than a robust phylogeny.

FIGURE 29. Lycopodina helios sp. nov., holotype QM G337468. A. Anisochelae. B. Large subtylostyles 1. C. Magnified ends of subtylostyle 1 depicted in B. D. Smaller subtylostyles 2. E. Magnified ends of subtylostyle 2 depicted in D. F. Sigmancistra. G.SEM of the sponge body and stalk. H. Holotype QM G337468 after fixation. I. SEM image of the styles supporting the membranous ectosome containing the anisochelae. J. SEM image of the stalk showing the membranous anisochelae ectosome over the subtylostyle bundle forming the stalk.