Dysidea teawanui, Mc Cormack & Kelly & Battershill, 2020

Mc Cormack, Samuel P., Kelly, Michelle & Battershill, Christopher N., 2020, Description of two new species of Dysidea (Porifera, Demospongiae, Dictyoceratida Dysideidae) from Tauranga Harbour, Bay of Plenty, New Zealand, Zootaxa 4780 (3), pp. 523-542 : 534-537

Dysidea teawanui sp. nov.

Figs 1 , 6–8

urn:lsid:zoobank.org:act:6476B247-9085-46A4-B7DE-7D8F97BEFBCA

Material examined. Tauranga Harbour, Bay of Plenty: Holotype— NIWA 113650 , 37.681° S, 176.171° E, 8 m, 27 Nov 2018. Paratypes— Pilot Bay , Tauranga Harbour , Bay of Plenty: NIWA 113651–113655 , 37.681° S, 176.171° E, 12 m, 09 Dec 2018, SCUBA dive .

Distribution. Tauranga Harbour, Bay of Plenty, New Zealand, 8– 12 m.

Description. Massive, spherical to hemispherical, multilobed cushions, frequently conjoined, forming broad matts covering up to 2.5 m 2 ( Fig. 6 A–E), typically 10–50 cm long, 6–50 cm wide, 7.5–10 cm high; immature specimens spherical with low surface mounds ( Fig. 6C ), often 3–4 cm long, 1.5–3 cm wide, 1.5–2.5 cm high. Larger specimens frequently only alive in the top 4–5 cm of the sponge; when torn, the base is usually dead with only the ladder-like primary fibres visible ( Fig. 7A ). Surface with regularly spaced conules, 1–3 mm in height ( Fig. 6 C–E), granular to the touch. Cobwebs of fibrillar collagen in the surface membrane are clearly visible, stretching between the tips of primary fibres, joining adjacent conules ( Fig. 6E ). Oscules are relatively large, up to 5 mm diameter, scattered over the surface, with raised translucent collars ( Fig. 6C, E ). Texture in life, soft, slightly elastic, compressible. In life, the sponge is covered in sediment, appearing as rock substrate. Colour in life beneath surface sediment, powder blue-grey externally ( Fig. 6 C–E; 7A), cream to tan, sometimes orange-tinged in the non-illuminated base, cream in ethanol. Dermal membrane translucent.

Skeleton. Large, thick, primary fibres, 483 (300–800) µm diameter, relatively uniform in their thickness, dominate the skeleton ( Fig. 7A ), forming an irregular, laddered reticulation ( Fig. 7B ) with thin secondary fibres 113 (80– 160) µm diameter, flanged where they join the primary fibres ( Fig. 8A, B ). Thin, clear, auxiliary secondary fibres are visible in places; about 15 µm thick ( Fig. 7B ). All secondary fibres are solidly cored, spongin along the edges of the fibres is not visible. The secondary fibres directly link the primary fibres or may form a reticulation between the primary fibres ( Fig. 8A, B ). Primary fibres diverge from the base of the sponge ( Fig. 7A ), forming meshes about 814–2567 µm long and 800–1500 µm wide. All fibres heavily cored with sand and foreign spicule fragments.

Ectosome cavernous, mesohyl shrinking between the fibres in the preserved specimen ( Fig. 7A ). Canals filled with detritus and sediment, possibly resultant from worm activity in the aquiferous canals. Ectosome about 108 (105–140) µm deep, reinforced by a thin layer of fibrillar collagen ( Fig. 8C ), strands of which stretch between the apex of the primary fibres ( Fig. 6E ). A translucent dermal membrane is raised by large primary fibres, rarely with any inclusions of detritus; unarmoured ( Fig. 8C ). Choanocyte chambers are obscured by the abundant detritus in the mesohyl.

Substrate, depth range and ecology. Found on sheltered rocky reef substrate, covering rocks and boulders to a depth of 10 cm, and on wharf pilings, 5–8 m deep. The clown nudibranch, Ceratosoma amoenum ( Cheeseman, 1886) predates on this species, and fan worms are often integrated into the matrix of the sponge.

Etymology. Named for Tauranga Moana, Te Awanui, a spiritual symbol of identity for all whanau, hapu and iwi living in the harbour catchment area (Te Awanui, Tauranga Moana; te reo Māori). This species name was accepted and approved by local Tauranga Moana iwi, Ngāti Ranginui, Ngāi Te Rangi and Ngāti Pūkenga.

Remarks. Dysidea teawanui sp. nov. has a highly characteristic morphology and colouration that separates it clearly, in the field, from D. tuapokere sp. nov. in the same location; D. teawanui sp. nov. forms massive, pale blue-grey, multi-lobed cushions or spheres while D. tuapokere sp. nov. forms a cavernous lilac mass of lobed branches. Only two species noted from New Zealand waters, Dysidea sp. ‘b’ of Brøndsted (1924) and D. elegans ( Nardo, 1847) sensu Brøndsted (1927) ( Table 1), vaguely resemble the characteristic cushion-shape of D. teawanui sp. nov.

Dysidea sp. ‘b’ Brøndsted, 1924, from a “sandy mud” seabed, at 46 m in Carnley Harbour on the Auckland Islands (see Brøndsted 1924: 165), provides a reasonable description of a sponge attached to shell, with a variable shape, but generally “oblong, lump-shaped”. The “greatest extent” was about 50 mm, the colour in life was “pale grey to greyish yellow” and the surface was conulose, conules being 1 mm high and 4 mm apart. The primary fibres formed an irregular network, generally running perpendicular to the surface and were about 160 µm thick. The thinner spongin fibres were “almost devoid of foreign particles”, and the primary fibres cored with sand grains and broken spicules. While the general form and colour in life are reminiscent of D. teawanui sp. nov., the fibres are much thinner than in the latter. Furthermore, as for D. tuapokere sp. nov., the possibility of conspecificity of D. teawanui sp. nov. with a Subantarctic New Zealand sponge, is low. Finally, with relatively clear secondary fibres, the sponge may be more closely comparable to several Chatham Rise species described by Bergquist (1961b) as Leiosella levis ( Lendenfeld, 1886) , Polyfibrospongia australis ( Lendenfeld, 1888) [now considered to be Fasciospongia turgida ( Lamarck, 1814) ( Van Soest et al. 2018a) ], or Euryspongia arenaria Bergquist, 1961b .

Dysidea laxa ( Lendenfeld, 1889: 671) , from 30–40 m in Port Philip Bay, Australia, is the only other Southwest Pacific species of Dysidea that has a massive, lobose morphology with a light bluish-violet colour in life. However, unlike for D. teawanui sp. nov., the surface is tuberculate, sand-armoured and the oscules are arranged in a longitudinal series along the sides of the lobes. The fibres of D. laxa are quite large (200–500 mm thick) but they form a highly irregular, angular network in which the primary fibres are not clearly pronounced, differentiating it further from D. teawanui sp. nov., which has a highly regular ladder-like architecture. While all fibres in D. laxa are charged with small, abundant sand grains, these are more irregularly scattered in the slender fibres (after Lendenfeld 1889).

Figures

FIGURE 1. Map showing type localities for new species, Dysidea tuapokere sp. nov. and D. teawanui sp. nov., from Tauranga Harbour, Bay of Plenty, New Zealand.

FIGURE 6. Dysidea teawanui sp. nov.: A. Massive, hemispherical, to multilobed specimens covering rocks and boulders at Dive Crescent, Tauranga Harbour at a depth of 5 m; B. Spherical specimen with predatory sea slugs Ceratosoma amoenum; C. Holotype NIWA 113650, showing the almost spherical morphology of smaller specimens, the regular conulose surface with raised, membranous oscules visible in profile on the surface; D. Surface of a massive specimen showing large apical oscules with raised membranous collars; E. Apical oscule showing regular distribution of conules and collagen fibrils stretching between conules.

FIGURE 7. Dysidea teawanui sp. nov., holotype NIWA 113650: A. Dense, ladder-like architecture of the primary and secondary fibres, showing the powder bluey-grey colouration of the freshly collected sponge; B. Macerated fibrous skeleton, showing densely aligned and anastomosing primary fibres, connected by slender, cored secondary fibres.

FIGURE 8. Dysidea teawanui sp. nov., holotype NIWA 113650: A. Two primary fibres joined by slender, fully cored, flanged, secondary fibres; B. Branching secondary fibres between two primary fibres; C. Ectosomal membrane containing fibrillar collagen in the surface. Note only traces of detritus in mesohyl.