Tedania (Tedaniopsis) tantula ( Kirkpatrick, 1907 )

Goodwin, Claire E., Berman, Jade & Hendry, Katharine R., 2019, Demosponges from the sublittoral and shallow-circalittoral (<24 m depth) Antarctic Peninsula with a description of four new species and notes on in situ identification characteristics, Zootaxa 4658 (3), pp. 461-508 : 496-497

Tedania (Tedaniopsis) tantula ( Kirkpatrick, 1907)

( Figure 21 )

Synonomy: Tedania tantula ( Kirkpatrick, 1907) , Oceanapia tantula Kirkpatrick, 1907 .

Specimens. BELUM. Mc 2015.600 Grotto Island , Verdansky Base (Site 1) (65°14.615’S, 64° 15.019’W), depth 14–24 m; 16/02/2015 . BELUM. Mc 2015.619 Grotto Island , Verdansky Base (Site 2) (65°14.529’S, 64° 15.451’W), depth 6–18 m; 16/02/2015 . BELUM. Mc 2015.686 Rocks NW of Laktionov Island (65°45.536’S, 65° 47.319’W), depth 6–23 m; 22/02/2015 . BELUM. Mc 2015.738 Port Charcot, Booth Island (65°03.853’S, 64° 01.868’W), depth 6–16 m; 23/02/2015 . BELUM. Mc 2015.778 Under Spiggot Peak, Orne Harbour (64°37.755’S, 62° 33.018’W), depth 5–21 m; collected by C. Goodwin and E. Priestley, 25/02/2015 . BELUM. Mc 2015.809 Neptune’s Bellows, Deception Island (62°59.607’S, 60° 33.601’W), depth 7–18 m; collected by C. Goodwin and E. Priestley, 26/02/2015 .

BELUM. Mc 2015.840 Diomedea Island (62°12.185’S, 58° 56.760’W), depth 10–18 m ; collected by C. Goodwin and E. Priestley, 01/03/2015.

Comparative material examined. BMNH 1908.2 .5.198 Oceanapia tantula Kirkpatrick, 1907 Holotype. Slides a–k (spicule preparations and tissue sections).

External morphology. In situ appearance ( Figure 21A ): Yellow orange tubular sponge which may be branched. Up to 10 cm in length. The oval tubes taper out to a pore sieve structure at their end. In all of our specimens the majority of the tube was covered in encrusting epiphytes and epizooids (algae, bryozoans, other sponges) and only the terminal pore sieve structures were visible and immediately apparent. The texture of the tubes is very chitinous and most un sponge-like—resembling a worm tube.

Preserved appearance. Tapered tube with smooth surface. Texture very firm. Alcohol coloured bright yellow.

Skeleton: The main choanosomal skeleton ( Figure 21B ) is formed of ascending columns of up to 20 styles mixed with onychaetes with some smaller intercrossing columns and many free styles. The outer ectosomal chitinous layer ( Figure 21C ) is formed of an ectosomal tangential layer of tornotes.

Spicules: Measurements from BELUM.Mc2015.600.

Styles ( Figure 21D ): 393(445)512 by 16(20) 22 µm abruptly pointed and usually curved.

Tornotes ( Figure 21E,F ): 404(438)452 by 7(12) 15 µm ends usually symmetrical.

Onychaetes 1 ( Figure 21G ): length 76(88) 103 µm.

Onychaetes 2 ( Figure 21H,I ): length 416(510) 694 µm.

Remarks. The spicule size ranges and external form of our specimen closely match those of the type (from our measurements of the Holotype (styles 460–550 by 18–22 µm; tornotes 320–390 by 10 µm; onychaetes 550–670 µm and 80–110 µm). The form of the styles differs slightly in that the majority of those in the holotype are modified into strongyles, where strongyle modifications were hardly ever found in our specimens. Rios (2006) also notes the presence of strongyle modifications in some of her specimens.

Paratedania Burton 1929 was erected for this species because of its densely packed layer of tangential megascleres as opposed to the bouquet-type arrangement found in other Tedania . However, Burton (1932) withdrew the genus and synonomised the species with Tedania (Tedaniopsis) massa Ridley & Dendy, 1886 as he noted that some T. massa specimens had patches of chitinous ectosome which had a similar arrangement of spicules, even though in the rest of the specimen the arrangement was normal. Whilst he notes a variety of forms, some with cuticle and some without, in T. massa and T. tantula he considered, given the similarities in spiculation and embryology, that they were not valid species.

Koltun (1964) states that while T. tantula is similar to T. massa in terms of skeletal arrangement its external form is more like that of T. actiniformis Ridley & Dendy, 1886 and recommended that, pending a revision of all Antarctic Tedania species, they be maintained as separate species. Desqueyroux-Faúndez & Van Soest (1996) and Van Soest (2002b) followed Burton (1932) in considering T. tantula as a junior synonym of T. massa Ridley & Dendy 1886 . Van Soest (2002c) re-examined the type specimen of T. tantula and noted that the tangential arrangement of spicules at the surface was probably induced by the shells of molluscs to which they were attached. Whilst he noted some differences in the tornote ending between T. tantula and T. massa he considered that, as this character is variable, conspecificity was still possible. Rios (2006) collected several specimens of T. tantula from the Antarctic Peninsula and notes that the tangential arrangement of spicules is present in the ectosomal layer even when the specimens are not attached to mollusc shells, therefore she maintains it as a valid species. We support this here and the in situ appearance also differs significantly from T. massa : the type specimen of T. massa is described as ‘massive, cake-like, attaining enormous dimensions’ whereas, as in our specimens the type of T. tantula is a thin-walled tube.

Distribution. This species is very abundant in the Antarctic and sub-Antarctic ( Koltun 1964, 1976). Records include the type location, Winter Quarters Ross Sea, ( Kirkpatrick 1907); McMurdo Sound ( Burton 1929); Ross Sea ( Pansini et al. 1994), Weddell Sea ( Gutt & Koltun 1995, Göcke & Janussen 2013). Antarctic Peninsula and Bellinghausen Sea ( Rios 2006).

Figures

FIGURE 21. Tedania (Tedaniopsis) tantula (Kirkpatrick, 1907). BELUM.Mc2015.600.A. In situ appearance. B. Choanosomal skeleton, scale bar 500 µm. C. Ectosomal skeleton, scale bar 500 µm D. Style. E. Tornote. F. Tornote ends. G. Small onychaete. H. Large onychaete. I. Large onychaete ends. Spicule scale bars all 10 µm.