Antarctotetilla grandis ( Sollas, 1886 )

Carella, Mirco & Uriz, Maria J., 2018, Description of two new genera (Antarctotetilla, Levantiniella) and a new species of Tetillidae, Zootaxa 4455 (2), pp. 295-321 : 305-306

Antarctotetilla grandis ( Sollas, 1886)

Synonymy: Tetilla leptoderma Sollas, 1886 ; Tetilla grandis var. alba Sollas, 1886 ; Craniella coactifera ( Lendenfeld, 1907) .

Material examined: holotype of Tetilla grandis NHM98.1.1.5 Sollas, 1886, Kerguelen, Subantarctic region; Antarctotetilla grandis , CEAB.POR.BIO.501b ANT 27123 and CEAB.POR.BIO.501aANT 27124, Newmayer, Antarctic coasts, -70° 52.21‘S, 10° 35.81‘W, 225–284 m depth, 0 1 April 2011; Tetilla grandis , MNHN-IP 2011 167, Terre D’Adelie, Antarctic coasts, -66°34'S, 141°204'E, 170–210 m depth, 13 January 2008.

GenBank accession numbers ( Carella et al. 2016): CEAB.POR.BIO.501b ANT 27123 ( KT124324 , KT124344 , KT124330 and KT124363 ) and CEAB.POR.BIO.501a ANT 27124 ( KT124325 , KT124346 , KT124331 and KT124364 ).

Description ( Fig. 6 ). Globular, almost spherical sponges, about 10 cm in diameter ( Fig. 6a ). Surface smooth; oscules numerous on small conical elevations of the sponge surface ( Fig. 6b ). Pores grouped in small depressions, widespread overall the surface ( Fig. 6c ). Color beige in life, yellowish brown in alcohol. Pseudocortex ( Fig. 6d ) composed of auxiliary oxeas loosely arranged perpendicularly to the surface, as in Antarctotetilla leptoderma . Anchoring anatriaene-made tufts.

Spicules ( Fig. 7 ; Table 1). Megascleres: oxeas I ( Fig. 7a ) large and fusiform: 3500–5513.8–7850 µm x 35 – 54.6–78 µm. Auxiliary small oxeas II ( Fig. 7b ): 600–1211.8–1900 µm x 6.2–20–35 µm. Anatriaenes I ( Fig. 7f ): 3340–9195–14550 µm x 17.5–26.3–30 µm in size with long and thin clades: 140–220.3–320 µm; rhabdomes fusiform, thicker at the middle and filiform at the terminal part. Anatriaenes II: 1650–3483.3–6000 µm x 8.7–15.6– 20 µm in size ( Fig. 7e ) with short clades: 50–75–120 µm and fusiform rhabdomes. Protriaenes I ( Fig. 7c ): 4180– 5217.7–8000 µm x 10 –28.4–42.5 µm, with clades of 60–152–280 µm long, usually one clade longer than the others two; rhabdomes tapering from the base of the clades to end in a filamentous termination. Protriaenes II ( Fig. 7d ): 1700–3152.7–5400 µm x 6.2–12–18.5 µm, with clades: 22.5–84.9–155 µm in length, usually one clade longer than the other two; rhabdomes tapering to a filiform end. Trichodal protriaenes ( Fig. 7g ) very small with filamentous rhabdomes: 465–931.6–1677.5 x 2.5–3.3–3.7 µm long and thin, 12.5–57.9–92.5 µm long clades. Microscleres: Sigmaspires ( Fig. 7h–i ): 12.5–13.5–15 µm in length.

Skeletal arrangement. The skeletal structure is typical of Tetillidae , made of bundles of oxeas together with anatriaenes and protriaenes, which radiate upward from the central part to the periphery. Spicules protrude the ectosome only rarely and thus the surface is almost even. Auxiliary oxeas arranged in palisade at the sponge periphery and scattered in the choanosomal zone. Trichodal protriaenes have been reported at the peripheral zone ( Sollas 1888), mostly around the incurrent canals under the grouped pores. Sigmaspires spread throughout the sponge.

Distribution and habitat. Antarctic coasts (Newmayer and Terre D’Adelie), Kerguelen Islands ( Sollas 1886; Lendenfeld 1907), on sediment and rocky substrates, from 45 to more than 600 meters of depth.

Remarks. The variety Tetilla grandis var. alba , which lacks the anchoring basal mass described by Sollas (1886), also seems to belong in Antarctotetilla .

Figures

FIGURE 6. Antarctotetilla grandis from Terre D’Adelie (MNHN-IP 2011 167). A. Arrows point to the conical elevations. B. Summit of a conical elevation, arrows point to the oscule. C. Pores grouped in small surface depressions. D. Transversal section.

FIGURE 7. Spicules of Antarctotetilla grandis from Terre D’Adelie (MNHN-IP 2011 167). A. Terminal part of a large fusiform oxea I. B. Auxiliary secondary oxea II. C. Large Protriaene I. D. Medium size protriaene II. E. Small anatriaene II. F. Large Anatriaene I. G. Trichodal protriaene. H, I. Sigmaspires.