Leuceta pyriformis, Dendy, 1913

LeuceTa cf. pyriformis Dendy, 1913

( Figs 19, 20; Table 10)

Synonyms: Leuceta pyriformis : Dendy 1913: 11; Dendy and Row 1913: 734; Tanita 1943: 392; Burton 1959: 180; Van Soest and De Voogd 2018: 82. Leuceta cf. pyriformis : Klautau et al. 2013: 455.

Type material: Holotype, BMNH 1925.11 .1.1120; Cargados Carajos, Indian Ocean, ‘Sealark’ Coll. ( XC5 A), 82 m depth. MEOW: Cargados Carajos / Tromelin Island. Burton (1963) mentioned the specimen XC5B as the holotype ( BMNH 1920.12.9.52); however, Dendy (1913) clearly indicated the specimen XC5A as the type.

Material examined: SAMA S1860, GAB, 35°02 ʹ 17″S, 135°05 ʹ 42″E, depth: 221 m, coll: GABRP, site IN2015 _C02_128, 4 December 2015 GoogleMaps . SAMA S1894, GAB, 34°17 ʹ 30″S, 132°42 ʹ 24″E, depth: 283 m, coll: GABRP, site IN2015 _C02_181, 7 December 2015 GoogleMaps . SAMA S1912, SAMAS1916 , SAMAS1930 ,GAB, 33°20 ʹ 13″S, 130°15 ʹ 27″E, depth: 189 m, coll: GABRP, site IN2015 _C02_395, 15 December 2015 GoogleMaps . SAMA S1951, GAB, 33°21 ʹ 56″S, 130°44 ʹ 52″E, depth: 198 m, coll: GABRP, site IN2015 _C02_398, 15 December 2015 GoogleMaps .

Colour: Beige to light brown in ethanol ( Fig. 19A).

Morphology and anatomy: Sponge massive and sub-spherical ( Fig. 19A). Surface smooth, covered with bright spicules. Te osculum is single and apical, without ornamentation. Te atrium can be large or reduced. Aquiferous system leuconoid.

Large and small triactines are present in the cortex ( Fig. 19B). In the choanosome there are mostly small triactines and a few tetractines surrounding the excurrent canals ( Fig. 19C). Te large triactines can also be observed dispersed in the choanosome and near the atrium ( Fig. 19D). Te atrial skeleton is thick and composed only of the small triactines ( Fig. 19D). Large excurrent canals can be seen in the atrium.

Spicules ( Table 10)

Large triactines: Regular (equiangular and equiradiate). Actines are conical, with blunt tips ( Fig. 20A). Size: 762.4 (±236.6)/82.2 (±25.5) µm. One large tetractine was observed (302.4/43.2 µm).

Small triactines: Regular (equiangular and equiradiate), but sagital spicules were also observed. Actines are conical,

straight, with rounded to blunt tips ( Fig. 20B, C). Size: 174.1 (±20.2)/15.3 (±2.2) µm.

Small tetractines: Regular (equiangular and equiradiate), but sagital spicules were also observed. Actines are conical, straight, with rounded to blunt tips ( Fig. 20D). Tetractines are not abundant. Teir apical actine is conical, frequently very thin (needle-like), but thicker apical actines are also present, smooth and sharp; occasionally they are very long ( Fig. 20D). Size: basal, 155.0 (±31.5)/13.0 (±1.5) µm; apical, 139.0 (±46.7)/8.7 (±2.9) µm.

Geographical distribution: Cargados Carajos/Tromelin Island ( type locality; Dendy 1913); the Seychelles ( Van Soest and De Voogd 2018); Northern and Central Red Sea ( Van Soest and De Voogd 2018); the Maldives ( Burton 1959); and four localities in the GAB (this study).

Ecology: Tis species was previously found from depths of 0–82 m (Dendy 1913, Van Soest and De Voogd 2018). Here, we extend its depth range to 283 m on the edge of the continental shelf (in fine sand and silt). Burton (1959) found this species at 27 m depth in ‘botom sof cream mud’ in the Maldives.

Taxonomic remarks: Tis is the first potential record of Leuceta pyriformis in Australia. Although the species is considered to be widely distributed in the Indian Ocean (see above), it had never previously been reported from Australia.

Te specimens from the GAB are morphologically very similar to Leuceta pyriformis from other regions. Spicule measurements are similar (large triactines, 1000/100 µm; small triactines and tetractines, 170/12.5 µm; see Table 6). However, it is referred to as Leuceta cf. pyriformis because only triactines were found in the atrial skeleton, whereas Dendy (1913) mentioned the presence of triactines and tetractines. Van Soest and De Voogd (2018) noted that specimens from Saudi Arabia and the Seychelles had only tetractines in the atrial skeleton. It is possible that Leuceta pyriformis has a variable composition of the atrial skeletal. It is also possible that the specimens are different species. Until more is known about the variability of the atrial skeleton, the GAB specimen is considered to be Leuceta cf. pyriformis .

Van Soest and De Voogd (2018) assumed that the records of Leuceta microraphis Haeckel, 1872 from the Red Sea published by Voigt et al. (2017) could represent Leuceta pyriformis . However, in the phylogenies determined in this study, those specimens grouped with Leuceta microraphis from different locations (as in the studies by Voigt et al. 2017, Klautau et al. 2020) and not with Leuceta pyriformis . Consequently, this record is not included in the list of synonyms.

In the molecular tree, there is also a sequence of the specimen MNRJ 13843, from Antarctica, previously identified as Leuceta cf. pyriformis by Klautau et al. (2013). Te specimens in this study did not group with it. Re-examination of the specimen MNRJ 13843 demonstrated that it is not Leuceta pyriformis , and it has been allocated as Leuceta sp. in this study.