Chondrocladia (Chondrocladia) freycinetensis, 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 : 114-117

Chondrocladia (Chondrocladia) freycinetensis sp. nov.

Figures 20 & 21 , Tables 10 & 12

urn:lsid:zoobank.org:act:6DF96499-A54D-435E-8A7E-9F7A3D2152C5

Material Examined:

Holotype: QM G337455 off Freycinet Peninsula , Station 4, Tasmania, Australia, 41° 43’ 49.8”– 41° 47’ 28.7” S, 149° 7’ 10.9”– 149° 9’ 20.9” E, 2820– 2751 m, Beam Trawl, Coll. Merrick Ekins on RV Investigator, Cruise IN2017_ V03 , Sample 4-145, 18/v/2017.

Paratype: QM G337999 off Jervis Bay , News South Wales, Australia, 35° 19’ 58.8”– 35° 19’ 55.2” S, 151° 15’ 28.9”– 151° 12’ 50.4” E, 2650– 2636 m, Beam Trawl, Coll. Merrick Ekins on RV Investigator, Cruise IN2017_ V03 , Sample 56-250.1, 29/v/2017

Etymology: Named after the national park on the Freycinet Peninsula, Tasmania, adjacent to the offshore study site.

Distribution: This species is so far only known from the type locality off the Freycinet Peninsula, Tasmania, and Jervis Bay, New South Wales, Australia, at bathyal depth.

Description:

Growth form: An erect pedunculate unbranched ‘crinorhiza’ form sponge, 140 mm long with a subglobular balloon-shaped body 13 x 23 mm ( Figure 20 A ). The anterior part of the body is flattened with a single central raised parasol on the apex. The stem is 85 mm long and 0.7 mm wide. The sponge has many basal rhizoid root-like processes, up to 30 mm long, with rootlets anastomosing to fine points at their ends. The filaments are retracted into the body, but the filament bases can clearly be seen protruding through the hispid ectosome ( Figure 21 A–B). The paratype is only 68 mm long and 0.4 mm in width, but is missing the lower part of the stem and the basal root like processes. Its body is 12 x 6 mm and lacks the apical parasol.

Colour: Pale cream on deck and in ethanol.

Ectosomal skeleton: The ectosome consists of a crust of mycalostyles perpendicular to the surface producing a hispid sponge body ( Figure 21 A–D). The ectosome is punctuated by holes through which round swellings can be seen within the endosome. The isochelae are also present in the ectosome. There is no ectosomal skeleton on the stem or basal rootlets, except where the stem meets the body, perhaps it may have been lost during collection.

Endosomal skeleton: The endosome consists of thick bundles of mycalostyles arising from the roots ( Figure 21 F ) and stem ( Figure 21 E ), then radiating outwards through the body, and terminating in spherical swellings, which most likely contain retracted filaments.

Megascleres: There are three different types of styles present in this sponge. The large mycalostyles that are present in the stem and body, holotype: (1550-(2213)-3240 x 21.5-(36.1)-64.7 μm, n=92), paratype (1390-(1760)- 2420 x 20.5-(29.8)-44.1 μm, n=29) ( Figure 20 D–E). In the stem and body there is also the rare very thin supporting styles, holotype: (548-(1602)-3120 x 6.0-(8.9)-14.9 μm, n=7), paratype: (458-(1178)- 2320 x 4.2-(6.0)-8.3 μm, n=6) ( Figure 20 H-I). The most common style is present in the body, the stem and the rootlets, holotype: (515-(883)- 1530 x 7.1-(17.2)-27.4 μm, n= 103), paratype: (575-(844)- 1200 x 5.6-(15.5)-23.2 μm, n=27) ( Figure 20 F–G).

Microscleres: Tridentate unguiferate anchorate isochelae in two size classes. Large isochelae 1, holotype: (51.4- (62.5)-71.1 μm length x 2.2-(5.3)-7.0 μm stem width, n=76), paratype: (40.2-(50.9)-62.9 x 3.0-(4.6)-6.2 μm, n=96) ( Figure 20 C ), small isochelae 2, holotype: (21.7-(29.6)-37.7 x 1.7-(2.7)-3.9 μm, n=56), paratype: (21.5-(31.1)-36.3 x 1.6-(2.8)- 3.7 µm, n=33) ( Figure 20 B ). Sigmas in two size classes: large sigmas 1 in holotype only (50.1-(67.7)- 86.2 x 1.9-(3.0)-3.7, n=4) ( Figure 20 K ) and small sigmas 2, holotype: (15.1-(20.8)-25.4 x 0.7-(1.5)-2.0 μm, n=22), paratype (16.1-(22.3)-31.7 x 1.1-(1.9)-2.4 μm, n=13) ( Figure 20 J ), the former with up to 90 o torsion, the latter close to 45 o torsion.

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

Remarks: This species is similar to Ch. (Ch.) antartica Hentschel, 1914 , as redescribed by Koltun (1964: 34), Göcke & Janussen (2013: 67) and Dressler-Allame et al. (2017: 196). However, all spicules, especially the isochelae and sigmas, are significantly smaller in Ch. (Ch.) freycinetensis sp. nov., overlapping slightly with the smallest specimen described by Dressler-Allame et al. (2017) ( Tables 10 , 12 ). The gross morphology of this new species also superficially resembles that of Abyssocladia bruuni (see Lévi 1964: 78) and illustrated in Koltun (1970: Pl. III), but our new species lacks abyssochelae. Although filaments were not visible in the holotype of Ch. (Ch.) freycinetensis sp. nov. it is assumed that these have retracted into the spherical swellings observed on the apex of the body.

Figures

FIGURE 20. Chondrocladia (Chondrocladia) freycinetensis sp. nov., A. holotype QM G337455. B. Small unguiferous arcuate isochelae. C. Large unguiferous arcuate isochelae. D. Large mycalostyle. E. Magnified ends of the mycalostyle illustrated in D. F. Small mycalostyle. G. Magnified ends of the mycalostyle illustrated in F. H. Thin style. I. Magnified ends of the mycalostyle illustrated in H. J. Small sigma. K. Large sigma.

FIGURE 21. Chondrocladia (Chondrocladia) freycinetensis sp. nov., A. holotype QM G337455, showing the parasol on top of the sponge body. B. Section through the body of the sponge showing the radial pattern of mycalostyle to the bases of the filaments. C. Hispid surface of the sponge body. D. Small mycalostyles penetrating the ectosomal layer of isochelae and sigmas. E. Stem of the sponge illustrating the longitudinal arrangement of mycalostyles. F. Diverging root like appendages also illustrating the longitudinal arrangement of mycalostyles.