Calyx shackletoni, Goodwin & Brickle, 2012

Goodwin, Claire & Brickle, Paul, 2012, Sponge biodiversity of South Georgia island with descriptions of fifteen new species, Zootaxa 3542, pp. 1-48 : 37-41

Calyx shackletoni sp. nov.

( Figure 21)

Type material: Holotype: Samples in 95% ethanol, tissue section and spicule preparation on slides. BELUM Mc 7585. Prion Island Site 1, South Georgia (54°001.590’S, 37°15.178’W); depth 17.6m; collected by C. Goodwin, D. Poncet, and P. Brewin, 19 th November 2010.

Skeleton Appearance Notes/Distribution

Network of multispicular fibres. Tubular and ramified with a central deep Type locality Marguerite Bay, Antarctic aquiferous cavity. Surface strongly spined by long spines up to 10mm long.

Radial spicule tracts with ends Globular with a large terminal oscule. Originally described as Gelliodes piercing surface Bristling with spikes 2–5mm long. benedeni. Type locality Antarctic..

Ascending paucispicular tracts Dichotomously branching cylindrical Type locality Terra Nova Bay, Antarctic connected by 2–3 transverse branches from a common base. Up to spicules. Ectosome perpendicular 40cm high. Surface areolate.

tufts of oxea.

Close–set tracts joined by ‘cross Cup shaped with coarsely pilose outer Originally described as Sigmaxinyssa bars’. surface. phakellioiodes (type of new genus). Type locality Antarctic.

Tracts of 6–10 oxea joined by Massive amorphous with lobate Ectosomal skeleton not shared by other tracts of 1–3. Ends of tracts processes. species in genus. Type locality Terra Nova penetrate the dermal membrane. Bay, Antarctic.

Ectosomal tangential crust of oxeas.

Not noted. Simple column. Surface covered with Originally described as Thrinacophora ‘aspérités’, rugosities, similar in structure simplex . Type locality Antarctic.

to Axinella.

Irregular network of paucispicular Cushion shaped with a few scattered Originally described as Gellius subtilis tracts joined by unispicular fibres. oscules. from Great Barrier Reef, Australia

Irregular mesh formed of Vase shaped sponge terminating in large Type locality South Georgia.

anastomising columns of oxea oscule. Covered in spiky projections.

Paratypes: Samples in 95% ethanol, tissue section and spicule preparation on slides. BELUM Mc 7622 and BELUM Mc 7628. Right Whale Bay, South Georgia (54°00.173’S, 37° 40.856’W); depth 18m; collected by C. Goodwin, J. Brown and S. Brown, 21 st November 2010 . BELUM Mc 7665. Husvik, South Georgia (54°10.280’S, 36° 40.422’W); depth 8.9m; collected by J. Brown, S. Brown, E. Wells 26 th November 2010 .

Other specimens: Samples in 95% ethanol, tissue section and spicule preparation on slides.

BELUM Mc 7580 , BELUM Mc 7582 and BELUM Mc 7585; Prion Island Site 1, South Georgia (54°001.590’S, 37°15.178’W); depth 17.6m; collected by C. Goodwin, D. Poncet, and P. Brewin, 19 th November 2010 . BELUM Mc 7604. Rosita Harbour Site 1, South Georgia (54°00.715’S, 37° 26.049’W); depth 16.4m; collected by C. Goodwin, P. Brickle, and S. Cartwright, 20 th November 2010 . BELUM Mc 7614 , BELUM Mc 7615 and BELUM Mc 7616. Rosita Harbour Site 2, South Georgia (54°00.649’S, 37° 25.618’W); depth 11.5m; collected by C. Goodwin, J. Brown, and S. Brown, 20 th November 2010 . BELUM Mc 7649. Jagged Point, Possession Bay, South Georgia (54°04.514’S, 37° 07.188’W); depth 10.4m; collected by C. Goodwin, D. Poncet and P. Brewin, 23 rd November 2010 . BELUM Mc 7658 and BELUM Mc 7662. Husvik, South Georgia (54°10.285’S, 36° 40.412’W); depth 18m; collected by C. Goodwin, D. Poncet and P. Brewin, 26 th November 2010 .

Comparative material examined: NMS.Z.1921.143.1419 Gellius arcuarius (Calyx) type specimen in alcohol, tissue section and spicule preparation prepared from type.

MNHN DT703 Calyx stipitatus Topsent, 1916 , Type specimen tissue section and spicule preparation. Images of the preserved type specimen .

BMNH 28.2.15.106 Discovery investigations Calyx arcuarius (Topsent) R.N.XCIV.IV. Stn 175. Specimen in alcohol.

BMNH 28.2.15.117 Discovery investigations Calyx arcuarius (Topsent) R.N.LXI.IV. Stn 160. Specimen in alcohol.

BMNH 26.10.26.235 Terra Nova Antarctic expedition 1910-13. Calyx stipitatus (Topsent) . Specimen in alcohol.

ZMB 4835 Siphonochalina linea (?) gaussina. Hentschel, 1914 Type specimen tissue slide and images of preserved specimen.

Etymology: Named, in recognition of its probable pan-Antarctic presence, after Sir Ernest Shackleton, polar explorer, and also for the Shackleton Scholarship Fund, which supported this work.

External morphology: In situ appearance: The type specimen is in the form of a cream heart shaped, stalked lobe and is 10cm high ( Fig. 21a). The appearance of the paratypes and other specimens is variable ( Table 11) but all have some sort of stalk. The largest specimens reach over 20cm in height. The larger specimens are stalked lobes; in some of these the ends are developed into flattened branches ( Fig. 21a). Sponges are pale yellow to cream in colour and have prominent oscules. The skeletal tracts are often visible through the surface visible as a mesh like pattern of lines and numerous large oscules are scattered over the sponge surface.

Preserved appearance: The type specimen is buff coloured and has a tough texture. The colour of other specimens ranges from cream to pale brown in colour but most have a tough texture.

Skeleton: The choanosomal skeleton has a regular appearance with ascending tracts of oxeas 2/3 spicules thick joined by single oxeas. There are also irregular thicker fibres of oxea up to 10 spicules thick (bottom right Fig. 21b). The base of the stalk is made up of several of these thicker fibres intertwined. The ectosome forms an irregular hexagonal to triangular mesh of oxeas, sides two spicules thick, joined by abundant sponging at the nodes ( Fig. 21c).

Spicules: ( Fig. 21d): Oxea: Chunky short oxea slight variation in length between specimens ( Table 11), in the type 144(158)178 by 12(16)22µm. The oxea are normally slight bent a third from each end giving an angular curve to the spicule. Thin oxea 1–2µm in width are also present.

Toxa: Toxa in the type specimen are an ox-horn shape, 54(80)100µm, and very abundant. The largest are similar in width to the thin oxea. In the paratypes toxa are abundant but in several of the other specimens they were so rare as to appear to be absent on initial inspection.

Remarks: Burton (1932) recorded several specimens, which have a similar external form to ours (from branching to flabellate) and similar with oxea size (180–280 by 11–18µm), although the width of the skeletal oxea tracts is reported as 20–40 spicules thick. He also noted the variable presence of toxa and concluded that these were of no taxonomic significance and therefore Calyx stipitatus Topsent, 1916 , which he identified his specimens with, was a junior synonym of Gellius arcuarius Topsent, 1913 ; he supposed the type specimen of the latter was a small broken piece of a fan. However, Gellius arcuarius , from examination of the type specimen, is a thin, probably encrusting, species (described by Topsent as 20x12x 3mm), which has similar sized toxa (70–110µm) but much larger oxea (350–400 by 12–15µm) and a confused choanosomal skeleton rather than the neat reticulation found in the genus Calyx . It conforms to the current definition of Haliclona (Gellius) and should be reassigned to this genus. In contrast Calyx stipitatus is described as a stalked sub-triangular species with prominent oscules and an ectosomal unispicular reticulation of oxea (300–325 by 17µm in description, we measured as 232(278)313 by 13(17)22µm in the type) but does not possess toxa. To add to the confusion between these species Desqueyroux-Faúndez & Valentine (2002b) in Fig. 3A depict the holotype RSME 1921.143.1419 as a flabellate stalked specimen but this image does not match the specimen held in the museum’s collections.

Our specimens have a similar skeleton to the type of Calyx stipitatus and match the definition of the genus (Desqueyroux-Faúndez and Valentine 2002b), but differ from C. stipitatus in that they possess smaller oxea and have toxa. The only other species of Calyx described from the Antarctic is Calyx kerguelensis ( Hentschel, 1914) , which Burton (1934) reported from South Georgia, however this species has oxea ranging from 260–320µm and sigma 22–40µm. In view of the confusion in Haplosclerid taxonomy we have examined descriptions of other Antarctic species within the family. Cladocroce gaussiana ( Hentschel, 1914) (originally described as Siphonochalina (?) gaussiana ) as figured in de Weerdt (2002), p857, has a similar external appearance and choanosomal skeleton. However these Figures are taken from various different museum specimens rather than the type. The type specimen does have a similar skeletal form and possess toxas similar to those of our specimens. However, both the toxa and the oxea of the type specimen are substantially larger (130–150µm and 240–280µm respectively— Hentschel (1914) gives 80–152 and 232–264µm). The type specimen is a small enlongated fragment and it is difficult to determine external form, however, it was much less robust in texture than our specimens. We are unable to find any matching species within the Haplosclerida , consequently we assign these specimens as a new species.

Distribution: It seems likely that our specimens are con-specific with some of Burton’s specimens assigned to C. arcuarius from the Antarctic, South Georgia and Shag Rocks ( Burton 1929; 1932; 1934) and in view of the similarity in appearance to other Antarctica specimens ( Brueggeman 1998) this species may be widespread and common in the Antarctic.