Rowella haeckeliana (Poléjaeff, 1883)

Rowella haeckeliana (Poléjaeff, 1883) View in CoL

( Figs 21, 22; Table 11)

Synonyms: Leuceta haeckeliana : Poléjaeff 1883: 69; Fell 1950: 10. Leucetusa haeckeliana : Dendy and Row 1913: 739; Burton 1932: 261, 1963: 553; Lopes et al. 2018: 66; Riesgo et al. 2018: 837. Leucilla haeckeliana : Fell 1950: 10. Leucetusa sp. 1: Voigt et al. 2012: 3. Rowella haeckeliana : Lopes and Klautau 2023: 34.

Type material: Syntypes, BMNH 1884.22.62-64; off Port Jackson , Sydney, NSW, Australia, ‘ Challenger’ Expedition (Station 163a), 3 June 1874, 55–64 m depth . MEOW: Manning–Hawkesbury .

Materialexamined: SAMAS1855 ,GAB, 35°02 ʹ 17″S, 134°05 ʹ 42″E, depth: 221 m, coll GoogleMaps : GABRP, site IN2015 _C02_128, 4 December 2015 . SAMA S1890, GAB, 34°17 ʹ 30″S, 132°42 ʹ 24″E, depth: 283 m, coll: GABRP, site IN2015 _C02_181, 7 December 2015 . SAMA S1928, GAB, 33°20 ʹ 13″S, 130°15 ʹ 27″E, depth: 189 m, coll: GABRP, site IN2015 _C02_395, 15 December 2015 . SAMA S1940, GAB, 33°21 ʹ 56″S, 130°44 ʹ 52″E, depth: 198 m, coll: GABRP, site IN2015 _C02_398, 15 December 2015 .

Colour: Beige in ethanol ( Fig. 21A).

Morphology and anatomy: Several tubular specimens with one apical osculum, without ornamentation, and a thinner region at the base similar to a peduncle ( Fig. 21A). Tere is a cavity inside this peduncle. Surface smooth. Te body wall is 0.1 cm thick. Te atrium is wide ( 0.6 cm), hispid, and with a few spherical excurrent canals. Aquiferous system leuconoid. All the specimens are full of embryos and larvae ( Fig. 21B). Te consistency of SAMA S1855 is like rubber.

Te cortical skeleton is composed of large triactines and very rare tetractines ( Fig. 21C, D). Tey lie tangentially to the sponge surface, and the tetractines project their apical actines into the choanosome, sometimes reaching the atrium. Pygmy triactines and tetractines are sparsely spread throughout the choanosome ( Fig. 21D, E). In the choanosome there are also canals, and they are surrounded by pygmy tetractines. Te atrial skeleton is composed of pygmy tetractines, larger than those of the choanosome, and rare pygmy triactines ( Fig. 21F). Te tetractines project their apical actines into the atrium ( Fig. 21E, F).

Spicules ( Table 11)

Cortical triactines: Regular (equiangular and equiradiate). Near the osculum they are sagital, sometimes with curved paired actines. Actines are cylindrical to slightly conical, with blunt tips ( Fig. 22A). Variable sizes. Size: 473.5 (±72.4)/21.8 (±4.3) µm.

Cortical tetractines: Regular (equiangular and equiradiate). Actines are cylindrical to slightly conical, with blunt tips ( Fig. 22B). Te apical actine is conical, very long and sharp. Size: basal, 540.5/32.4 µm; apical, 695.0 (±296.8)/37.8 (±17.9) µm.

Choanosomal and atrial triactines: Regular (equiangular and equiradiate). Tese spicules are tiny, and they are not as abundant as the tiny tetractines. In the peduncle they are rare. Actines are cylindrical to conical, with sharp tips; when they are conical there is a thickening near the centre of the spicule, which appears to be deformed. Actines are frequently undulated ( Fig. 22C). Occasionally, these spicules loose one actine, becoming similar to a boomerang. Size: 30.3 (±17.9)/3.6 (±1.6) µm.

Choanosomal and atrial tetractines: Regular (equiangular and equiradiate). Actines are cylindrical or conical, with sharp tips; when they are conical there is a thickening near the centre of the spicule, which appears to be deformed ( Fig. 22D). Actines are frequently undulated. Te apical actine is conical, sharp, smooth, and straight or slightly curved. It is frequently thicker and longer than the basal actines. Size: basal, 31.8 (±10.3)/3.7 (±1.3) µm; apical, 74.5 (±13.8)/5.7 (±0.9) µm.

Geographical distribution: Manning–Hawkesbury (Poléjaeff 1883); Bassian ( Voigt et al. 2012); possibly Malvinas /Falklands ( Burton 1932); possibly Agulhas Bank ( Burton 1963, based on a slide from T. Mortensen), and four localities in the GAB (this study). Te occurrence of Rowella haeckeliana in Malvinas /Falklands and in South Africa should be regarded with caution, because the identification could not be confirmed ( Lopes and Klautau 2023).

Ecology: Rowella haeckeliana was originally found at depths of 55–64 m (Poléjaeff 1883). Later, it was collected at a depth of 174 m (specimen analysed by Voigt et al. 2012) and now from depths of 189–283 m on the edge of the continental shelf (in fine sand and silt). Lopes and Klautau (2023) mentioned the range in depth for this species as 55–2000 m, but this was an error. Te correct bathymetry for this species is depths ranging from 55 to 283 m. Tis species has already been found atached to hard and sof botoms, such as sand and shells ( Lopes and Klautau 2023). Here, the specimens were found on sof botom.

Remarks: Rowella haeckeliana was originally described from eastern Australia (Port Jackson), by Poléjaeff (1883). Specimens from this study match the morphology of the syntype. Te cortical triactines are cylindrical and very thin, the cortical tetractines are very rare, and the pygmy spicules are widened at the base. In the GAB specimen, the cortex varies from a thin layer to multiple layers, not as thick as the choanosome, whereas in the syntype the cortex and the choanosome are almost the same thickness. Specimens examined here are full of embryos and larvae; therefore, it is possible that this variation is atributable to the reproductive state of this species, and the specimens from the GAB have been identified as Rowella haeckeliana .

Tis species is morphologically very similar to Rowella imperfecta (Poléjaeff, 1883) , another species from eastern Australia. However, the cortical tetractines are abundant in Rowella imperfecta and they can occur in the choanosome, whereas Rowella haeckeliana has very rare cortical tetractines restricted to the cortical skeleton, never present in the choanosome.

Clathrinida incertae sedis Borojević, Boury-Esnault, Manuel & Vacelet, 2002