Leucaltis nodusgordii ( Poléjaeff, 1883 )

Van, Rob W. M. & De, Nicole J., 2018, Calcareous sponges of the Western Indian Ocean and Red Sea, Zootaxa 4426 (1), pp. 1-160 : 66-70

Leucaltis nodusgordii ( Poléjaeff, 1883)

Figures 37a–e , 38a–f .

Heteropegma nodusgordii Poléjaeff, 1883 (in part, only the Torres Strait material): 45, pl. I fig. 7, pl. IV figs 1a–d.

Leucaltis clathria ; Dendy 1913: 16, pl. 1 figs 1–2; Hôzawa 1940: 136, pl. VI fig. 3; Wörheide & Hooper 1999: 876, figs 7I –S (not: Haeckel 1872).

Leucaltis nodusgordii ; Van Soest & De Voogd 2015: 39, figs 28a–c, 29a–d, 30a–e (with further synonyms).

Material examined. ZMA Por. 12436, Seychelles, Amirantes, Desroches Atoll, SW rim, outer reef slope, 5.7167°S 53.6167°E, depth 5–30 m, scuba, coll. M.J. de Kluijver, field nr. NIOP-E stat. 774/03, 30 December 1992; ZMA Por. 12443, Seychelles, Amirantes, Poivre Atoll, N rim, outer reef slope, 5.7333°S 53.3167°E, depth 7–8 m, scuba, coll. R.W.M. van Soest, field nr. NIOP-E stat. 768/08, 31 December 1992; ZMA Por. 16248, Seychelles, Mahé, SE coast, Anse Royale Bay, 4.7333°S 55.5167°E, depth 2–13 m, scuba, coll. R.W.M. van Soest, field nr. NIOP-E stat. 740/04, 24 December 1992; ZMA Por. 20623, Seychelles, Mahé, NE Point, 4.5833°S 55.4667°E, depth 0–5 m, snorkling, coll. R.W.M. van Soest, field nr. NIOP-E stat. 604, 8 December 1992.

Description. Because this species has been treated recently in Van Soest & De Voogd (2015), we refrain from extensively describing the Seychelles material. The species forms masses of loosely anastomosed tubes ( Fig. 37a ), size up to 3 x 4 cm, individual tubes approximately 0.5 cm in diameter. Color pale blue or bluish white in situ, white in preservation. Some of the tubes have open endings, presumably oscules. Consistency fragile, surface optically smooth, but feels rough.

Aquiferous system. Elongate, ramified choanocyte chambers, supported by small equiangular spicules.

Skeleton. ( Figs 37–e ) In cross section ( Fig. 37b ) from outside to atrium, there is a cortical skeleton of giant tri- and tetractines ( Fig. 37c ), a choanosomal skeleton ( Fig. 37d ) of small thin equiangular and equiradiate tri- and tetractines, and an atrial membrane ( Fig. 37e ) supported by small sagittal (‘abruptly’-angled) tri- and tetractines.

Spicules. ( Figs 38a–f ) Giant tri- and tetractines, small regular tri- and tetractines, small sagittal tri- and tetractines.

Giant tetractines ( Figs 38a ), quite variable in size, similar in shape and size to the giant triactines, actines 144– 571 – 1020 x 18 – 79.8 –126 µm.

Giant triactines ( Figs 38b ), quite variable in size, equiangular and equiradiate, with thick conical actines measuring 102– 505 –960 x 14 – 60.2 –138 µm.

Regular equiangular equiradiate tetractines ( Fig. 38c ), with thin cylindrical actines; basal radiate actines 60– 73 – 84 x 2 – 2.4 –4 µm, with apical actines 9– 20.7 – 28 x 2 – 2.1 –3 µm.

Regular equiangular equiradiate triactines ( Fig. 38d ), with thin cylindrical actines measuring 59– 66.9 – 78 x 2 – 2.1 –3 µm.

Sagittal, abruptly angled tetractines ( Fig. 38e ), with unpaired actines 39– 57 – 69 x 2.5– 3.5 –5 µm, paired actines 60– 69 – 84 x 2 – 3.4 –5 µm, apical actines 18– 29.8 – 45 x 2 – 2.9 –5 µm.

Sagittal, abruptly angled triactines ( Fig. 38f ), similar to the sagittal tetractines, with unpaired actines 36– 50 – 63 x 2 – 2.8 –4.5 µm, paired actines 54– 64 – 81 x 2 – 3.1 –4.5 µm.

Distribution and ecology. Seychelles, Cargados Carajos, Australia, Sri Lanka, Indonesia, on reefs at depths down to 88 m.

Remarks. The data for the Seychelles specimens closely conform to those of the Indonesian material described by us recently. Size of the Seychelles specimens is smaller than the Indonesian ones, but individual tubes are similar in both. The giant tetractines of the Indonesian specimens were reported as somewhat larger. Unfortunately, Dendy’s (1905) record of this species from Sri Lanka was not described, so we do not know whether this inbetween locality had inbetween sizes.

We obtained sequences of an Indonesian specimen described in our 2015 paper (RMNH Por. 1772) and two of the Seychelles specimen (ZMA Por. 12436 and 12443) treated here. We also downloaded longer 28S sequences from GenBank of a Panamanian (Caribbean) Leucaltis sp. = L. clathria ( Haeckel, 1872) , proclaimed a different species by us (Van Soest & De Voogd, 2015; Van Soest, 2017), and two Australian sequences named L. clathria ( Haeckel, 1872) (acc.nrs. JQ272302 and AY563542 ), which are assumed to be conspecific with Indonesian and Seychelles specimens of L. nodusgordii . As the detailed relationships between these specimens are not clearly apparent in Fig. 2B , we did a separate analysis of the aligned and trimmed sequences of these six specimens (alignment length 369 sites), which showed 21 non-conserved sites. Where the maximum site difference between the five sequences from the Indo-West Pacific was 6 or less, the Panamanian sequence had 11 unique nonconserved sites, along with two non-conserved sites shared with Indonesia and one with Australia. This supports the previously claimed separate specific status of the Caribbean Leucaltis populations, even though the differences among the specimens are not significant enough to show up in the phylogenetic analysis of our Fig. 2B.

A possible junior synonym of Leucaltis nodusgordii is Leucaltis bathybia var. mascarenica Ridley, 1884 , reported from the Amirantes, very near to two of our collected specimens (ZMA Por. 12436 and 12443). Ridley’s description of the habit and the large tetractines sounds close to our material, but there is not sufficient information to be certain. Leucaltis bathybia Haeckel, 1872 from 600 m depth in the Red Sea is not conspecific judging from its description (see also below). It is assigned to Leucandra at present (see Van Soest et al. 2018), but the predominance of large tetractines makes it more likely that it belongs to Leucilla . L. bathybia was associated with Sycettusa (Calcaronea, Heteropiidae ) by Burton (1963, p. 318) but this cannot be accepted.

Figures

FIGURE 2. Maximum-likelihood tree based on analysis of sequences of the partial 28S gene (C2–D2 region, comprising 442 sites) of Western Indian Ocean Calcinea newly generated by the Naturalis Biodiversity Center and sequences additionally obtained from GenBank, the Sponge Barcode Project and from Oliver Voigt (München) from the Red Sea, Indonesia, Australia, and a few sequences from other parts of the world, to demonstrate the affiliation of the compared species. Please note that Arturia sequences do not appear in the same clade, indicating Arturia is non-monophyletic. Numbers at the root of clades are bootstrap values of 1000 replicates. Since the high number of sequences were difficult to read in detail, we subdivided the present tree in three detailed sections 2A, 2B, and 2C.

FIGURE 37. Leucaltis nodusgordii (Poléjaeff, 1883), ZMA Por. 16248, from the Seychelles, a, preserved habitus (scale bar = 1 cm), b–e, SEM images of the skeleton, b, cross section of tube, c, surface of the tube showing cortex of giant tri- and tetractines, d, part of the choanosomal skeleton showing small regular tri- and tetractines, e, atrial skeleton of sagittal ‘abruptly’ angled tri- and tetractines.

FIGURE 38. Leucaltis nodusgordii (Poléjaeff, 1883), ZMA Por. 16248, from the Seychelles, a–f, SEM images of the spicules, a, cortical giant tetractines, b, cortical giant triactines, c, choanosomal regular tetractine, d, choanosomal regular triactine, e, atrial sagittal ‘abruptly’ angled tetractine, f, atrial sagittal ‘abruptly’ angled triactine.