Euchelipluma claudochela Ekins & Erpenbeck & Hooper 2020, sp. nov.

Euchelipluma claudochela sp. nov.

Figure 32, Table 17

urn:lsid:zoobank.org:act: 0DD6EF16-32D2-4ED9-9B01-DC48F5B96964

Material examined: Holotype: QM G337511 Central Eastern Commonwealth Marine Reserve, Off Central New South Wales, Australia, 30° 15’ 50.3994”– 30° 17’ 12.1194” S, 153° 52’ 12”– 153° 49’48.7194” E, 4481– 4414 m, Beam Trawl, Coll. Merrick Ekins on RV Investigator, Cruise IN2017_ V03, Sample 88-126, 6/vi/2017 (all of the sample is on an SEM stub).

Etymology: Claud, L. for closed, refering to the teeth of the abyssochelae of this species.

unknownsubtylostyles 553–1004 x 9unknownplacochelae 13–15 x 4unknown18–21Off Loggerhead Key, Carribean, bathyal

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Erect stipitate, with short naked constricted stem, slightly widened and flattened body bearing short spines paired or in 3 rows, slightly widened basal attachment14–22Axis of main stem cored by subtylostyles 1 condensed near base, divided into parallel fibres upwards, with tufts of subtylostyles 2 inserted into fibres symmetrically, ascending spicular- fibres spread in the body cored by subtylostyles 3, with strongyles in the basesubtylostyles 1, 1000 x 30subtylostyles 2, 400–600 x 11 subtylostyles 3, 600 x 20strongyles 240–370 x 10–14placochelae 60–73 x 15palmate isochelae 80–1001, 22–24 2, 12SW of l’île BoaVista, Cape Vert, NW Atlantic, photic

Distribution. This species is presently known only from type locality off the central coast of New South Wales, Australia, abyssal depth.

Description:

Growth form: The sponge is an erect, stipitate, moderately thin stem, sawfish-shaped sponge 14 mm in length, 0.5–0.7 mm in diameter, with short bilateral filaments (Figure 32 A). Unfortunately the base of the specimen was not collected, and as such no basal rootlets could be examined for the potential presence of basal desmas in this species.

Colour: White on deck.

Ectosomal skeleton: The ectosomal skeleton is thin and membranous, containing abyssochelae, the less common placochelae and the sigmancistras (Figure 32 I).

Endosomal skeleton: The axis of the stem and filaments consist of bundles of larger mycalostyles longitudinally arranged (Figure 32 G–I). The smaller oxetote styles are packed together around the mycalostyles forming a sheath (Figure 32 H).

Megascleres: Large mycalostyles with long tapering points and gradually tapering bases, thickest about 60– 70% towards the basal end (404-(904)- 1060 x 8.9-(19.8)-27.4 μm, n=16) (Figure 32 E). Small oxeote styles with long tapering points and abruptly tapering bases, thickest at the centre of the spicule (78-(189)-456 x 4.3-(10.1)- 22.6 µm, n=46) (Figure 32 F).

Microscleres: Large placochelae with frontal alae nearly completely detached and lateral alae completely fused to the fimbria (31.5-(61.3)-74.7 x 9.2-(13.6)-18.0 µm, n=62) (Figure 32 B).

Abyssochelae with both upper and lower frontal and lateral alae nearly fused (12.4-(17.2)-22.7 x 6.5-(10.5)- 13.2 µm, n=53) (Figure 32 C). Small slightly contort sigmancistras (5.3-(6.4)-8.7 x 1-(1)- 1 µm, n=57). (Figure 32 D).

Molecular data: It was not possible to get unambiguous molecular data from the type material.

Remarks: This species is unique amongst the four known Euchelipluma species, by a combination of its morphology and the unique shape of the abyssochelae, whereby upper and lower alae are nearly fused together. Euchelipluma claudochela sp. nov. is most similar in growth form to the shape of the Alaskan species, E. elongata Lehnert, Stone & Heimler, 2006, for which it also shares the possession of fusiform (mycalo-)styles and a single category of sigmancistras. The new species, however, lacks the tylostyles and has uniquely shaped abyssochelae, whereas E. elongata has palmate-arcuate isochelae. Euchelipluma claudochela sp. nov. also differs from E. arbuscula (Topsent, 1928c) in lacking strongyles, subtylostyles, desmas and the large sigmas, having abyssochelae instead of isochelae in the latter.

Euchelipluma congeri de Laubenfels, 1936 from the Caribbean, is poorly known only from its description, but has a very different morphology and possesses (sub)tylostyles.

Euchelipluma pristina Topsent, 1909 also has three categories of subtylostyles, strongyles in the basal skeleton, two sizes of sigmas and very different isochelae morphology compared to E. claudochela sp. nov. (see Table 17).

Hestetun et al. (2016a) recovered Euchelipluma as a sister group of Abyssocladia based on the common possession of arcuate isochelae, the shape of the sigmancistras, and molecular data (the latter data with varying support), but the latter genus, up until now, lacking placochelae. The discovery of this new species E. claudochela sp. nov., with abyssochelae lends further support to this hypothesis proposed by those authors.