Guitarra davidconryi, Ekins & Erpenbeck & Goudie & Hooper, 2020

Ekins, Merrick, Erpenbeck, Dirk, Goudie, Lisa & Hooper, John N. A., 2020, New carnivorous sponges and allied species from the Great Australian Bight, Zootaxa 4878 (2), pp. 240-266 : 255-258

Guitarra davidconryi sp. nov.

Figure 8 , Table 4

urn:lsid:zoobank.org:act:E17354FE-8DB8-4821-AD2C-BEF8A5FD5A63

Material Examined: Holotype SAMA S2161 , Commonwealth Marine Reserve, Great Australian Bight , South Australia, SZ 12, 35 o 40’ 46” S 135 o 41’ 37” E, 137 m, Smith-McIntyre grab, Coll. CSIRO on RV Investigator, Cruise IN 2017_C01, sample IN2017_C01_ SMG_212b, 24 April 2017.

Etymology: This species is named for Mr David Mark Conry AM, outgoing Chair of the Board of the Queensland Museum and Co-Founder of Youngcare, in recognition of his guidance, great support, and generosity of his time during some challenging periods.

Distribution: This species is presently known only from a single specimen from the Great Australian Bight, epipelagic depth.

Description: Growth form: The holotype is composed of two small fragments, the largest is a small tear dropshaped fragment only 5 mm in length ( Fig. 8 A ), presumably from a much larger body, of which the remainder is unknown. All of the fragments of the holotype are now mounted on the SEM stubs and microscope slides.

Colour: Off-white after preservation in ethanol.

Ectosomal skeleton: The ectosome consists of a disorganised array of anisoxeote styles tangential to the surface, with occasional placochelae also distributed on the surface.

Endosomal skeleton: The endosomal skeleton consists of widely spaced bundles of oxeas meeting the ectosome at an obtuse angle. Here the mesohyl contains the acanthoisochelae microscleres.

Megascleres: Oxeas slightly curved with greatest thickness at the centre of the spicule, tapering to abrupt points (102–(139)–194 x 1.5–(3.8)– 5.3 µm, n=62). Very thin long sinuous styles slightly curved approximately one-third of their length towards the basal end, base tapering, slightly rounded, almost anisoxeote, points long and tapering (226–(310)–360 x 1.4–(3.9)–6.0 µm, n=41).

Microscleres: Placochelae (26.5–(37.7)–48.6 x 8.1–(13.4)– 19.8 µm, n=34). Palmate acanthoisochelae (6.4– (10.5)–14.3 x 0.4–(0.8)– 1.4 µm, n=47).

Molecular data: Due to the size of the small sample all of the material was used in the manufacture of microscope slides and SEM stubs.

Remarks: Guitarra davidconryi sp. nov. is the first record of the genus from the Australian Exclusive Economic Zone (EEZ). The new species is most similar to G. indica Dendy, 1916 from shallow subtidal depths of Poshetra, India, in the morphology of its anisoxeote styles (which Dendy terms ‘tornostrongyles’), but differs in its gross morphology (massive versus cushion-shaped), and the possession of oxeas in addition to styles as megascleres. Dendy’s illustration of placochelae ( Dendy 1916, Pl. I, Fig. 5b ) depicts both mature and juvenile forms, with the latter referred to as developmental stages, but which are more likely to be palmate acanthoisochelae, similar to those in G. davidconryi sp. nov., G. laplani Boury-Esnault et al., 1993 , G. sepia Lerner et al., 2004 , and G. solorzanoi Cristobo, 1998 .

To some extent this new species also resembles the brief description of G. novaezealandiae Dendy, 1924 from epipelagic depths in New Zealand, in its morphology, size of oxeas and placochelae, but differs from the latter in having styles as well as oxeas as structural megascleres, palmate acanthoisochelae and lacking sigmas. This species also bears some resemblance to G. exoclavata ( Lévi, 1993) from mesophotic depths off New Caledonia, which is cushion shaped, has oxeas and exotyles as megascleres (both of which are magnitudes of size larger than the equivalent megascleres of G. davidconryi sp. nov.), two sizes of placochelae, and tiny bipocilla-like isochelae. Guitarra bipocillifera Brøndsted, 1924 also from New Zealand epipelagic depths, synonymised with G. fimbriata Carter, 1874 by Bergquist & Fromont (1998) but an action not universally accepted by subsequent authors (e.g. Carballo

& Uriz 1998, Van Soest et al. 2018), has one type of spiny bipocilla-like isochelae similar to the palmate acanthoisochelae of G. davidconryi sp. nov. but lacks styles and has larger placochelae. A comparison of morphological characters found in all currently known species of Guitarra is presented in Table 4 .

Figures

FIGURE 5. Abyssocladia oxyasters sp. nov., A. Upper surface of the sponge body showing the cleistochelae on the exterior of the ectosome, and the oxyasters in the underlying endosome above the mycalostyles. B. Copepods commonly occurring in the endosome with the oxyasters. C. Stem of the holotype showing the cleistochelae on the endosome and the underlying mycalostyles. D. Two filaments showing the abundant sigmancistras and cleistochelae in the ectosome and the underlying mycalostyles in the endosome.

FIGURE 8. Guitarra davidconryi sp. nov., holotype SAMA S2161. A. Holotype fixed. B. Placochela. C. Placochelae in various orientations. D. Palmate acanthoisochelae. E. Oxea. F. Magnified ends of the oxea depicted in E. G. Anisoxeote style. H. Magnified ends of the style depicted in G. I. SEM showing the ectosome and the underlying choanosomal skeleton. J. SEM close-up of the ectosomal skeleton showing the sinuous styles, placochelae and the isochelae in situ. K. Detail of a placochela with one alae removed to show the underlying siliceous filaments.

Tables

Table 4. Comparison of all known species of Guitarra.

Species	Source	morphology	Colour	oscules	Ectosome	Choanosome	Oxeas (µm)	Styles (µm) (LxW)	Placochelae	Biplacochelae	Palmate	Bipocilla	Sigmas	Locality	Depth (m)
							(LxW)		(µm)	(µm)	acanthoisochelae	like	(µm)
											(µm)	isochelae
												(µm)
Guitarra davidconryi	present work	teardrop shaped	off-white	not observed	disorganised array	widely spaced	102-194 x	sinuous 226-360 x	26.5-49 x 8-20	absent	6-14 x 0.4-1.4	absent	absent	Great Australian	137
sp. nov.		fragments of a	preserved		of anisoxeote styles	bundles of oxeas	1.5-5.3	1.4-6.0						Bight, South
		larger more massive			tangential to the	meeting the								Australia
		specimen			surface	ectosome at an
						obtuse angle
Guitarra abbotti Lee,1987	Lee, 1987:465,	encrusting to massive,	brown	clustered 1 -6 mm	spicular brushes of	regular isotropic	absent	249-396 x 5-9	large 64-100	23-46	absent	3-14	absent	California,USA	34-46
	Figs 1-13	ovoid or pulvinate			bundles of styles	reticulation			small 27-53
		when small,			penetrating surface	of bundles of
		digitate and irregular				styles
		when massive
Guitarra antarctica	Hentschel, 1914:	massive to spherical,	whitish brown	small, narrow slit-	microscopically	loose net-like	408-496 x	absent	95-110 x 33-40	absent	absent	absent	23-28	Antarctica	380-385
Hentschel,1914	75-76,Pl.VI,	surface fairly smooth		shaped openings	hispid with spicule	reticulation as	7-11		45-55 x 12-13
	Fig.4			with raised edges	bundles ending in	well as scattered
					clumps	oxeas
Guitarra bipocillifera	Brøndsted,	massive rounded,	light grey	scattered 1mm	choanosomal tract	regular	320-425 x	Nil	23-101	absent	absent	10-13	absent	part New Zealand	55-110
Brøndsted, 1924	1924:458 -	lump-shaped	preserved,		of oxeas fan into	isodictyal	5-10
	459, Fig.16;	to globular,	white alive		brushes at surface	triangular
	Bergquist &	characteristic furrowed				reticulate of
	Fromont 1988:	compartmentalised				oxea spicule
	40-42,Pl.14	surface, finely hispid				bundles,with
	D-F,Fig. 15					many oxeas
	A-C (the latter					also scattered in
	synonymised					mesohyl
with G.
fimbriata Carter)
Guitarra endyi (Kirkpatrick,	Kirkpatrick,	small cushion, narrow	pale brown in	Nil	protective armour	radiating	absent	exotyles 358 x 6.5	85 x 30	absent	absent	absent	9 x 5	Antarctica	240
1907)	1907:285-286	base	preservative		formed by gigantic	bundles of		strongyles 468 x 10
					spheroidal heads of	exotyles
					exotyles
Guitarra exoclavata (Lévi,	Levi,1993: 46,	hemispherical plano-	light grey	Nil	bundles of long	bundles of oxeas	420-520 x	exotyles 810-800 x 7-10	1, 55-65 x	absent	absent	8	absent	New Caledonia	500-510
1993)	Fig.13D,Pl.V,	convex cushion-			exotyles on the	criss-crossing	8-10		20-23
	Fig.5-6, Pl XI,	shaped			surface and irregular	throughout the	280-300 x		2, 32-36 x
	Fig.9-11				tangential oxeas	choanosome	8-10		8-10

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