Mycale (Naviculina) cliftoni ( Gray, 1867 )

Van, Rob W. M., Aryasari, Ratih & De, Nicole J., 2021, Mycale species of the tropical Indo-West Pacific (Porifera, Demospongiae, Poecilosclerida), Zootaxa 4912 (1), pp. 1-212 : 152-154

Mycale (Naviculina) cliftoni ( Gray, 1867)

Figs 97 a–c, 98a–d

Naviculina cliftoni Gray, 1867: 538 ; Hooper & Wiedenmayer 1994: 293; Hajdu 1999: 227, figs 1–2.

Mycale (Naviculina) cliftoni ; Van Soest & Hajdu 2002: 681, fig. 8; Lerner & Hajdu 2002 (keyed out).

Material examined. ZMA Por.P. 12186 (slide only), Indonesia, Nusa Tenggara, N of Sumbawa, Bay of Sanggar, 8.3383°S 118.2733°E, sea grass field and corals, depth 8–11 m , SCUBA, coll. R. W.M. van Soest, Indonesian-Dutch Snellius II Expedition stat. 122, field nr. 122 / IV, 22 September 1984 (separated from ZMA. Por. 08540, Cliona spec.) ; ZMA Por. 11188, Seychelles, Mahé, NE of Aride Island, 4.1667°S 55.7333°E, depth 55 m, Agassiz trawl, coll . R. W.M. van Soest, Netherlands Indian Ocean Expedition stat. 714, field nr. IOP-E 714/03, 19 December 1992 (slide only, specimen could not be found in 2019) (live color orange) ; ZMA Por. 12655, Seychelles, Amirantes, N of Platte Island Atoll , 5.8167°S 55.3667°E, depth 6 m , SCUBA, coll. R. W.M. van Soest, Netherlands Indian Ocean Expedition stat.796, field nr. IOP-E 796/45, 7 January 1993 (orange) ; ZMA Por. 12659, Seychelles, Amirantes, S of D’Arros Island, 5.4667°S 53.3°E, depth 50–55 m, Agassiz trawl, coll . R. W.M. van Soest, Netherlands Indian Ocean Expedition stat.764, field nr IOP-E 764/11a, 28 December 1992 ; ZMA Por. 12660, Mahé, W coast, Port Launaye National Park , 4.6333°S 55.3833°E, on oyster Lopha cristata , depth 1–7 m, snorkeling, coll . R. W.M. van Soest, Netherlands Indian Ocean Expedition stat. 605, field nr. IOP-E 605/05, 9 December 1992 .

Description ( Figs 97 a–b). The material identified as this species comprise predominantly thin crusts ( Fig. 97a ), but one sample, ZMA Por. 11188 (unfortunately it could not be found in the collection in 2019) consists of larger branches of 1.5 cm thick and 10 cm high ( Fig. 97b ). The surface of the branched specimen is optically smooth, although bumpy in places, with easily detachable ‘skin, overlaying a fibrous interior. Color of all reported specimens is orange in life, becoming whitish in preservation. Consistency soft.

Skeleton ( Fig. 97c ). The choanosomal skeleton consists of thick spicule tracts, 150–250 µm in diameter (up to 30 spicules in cross section), arranged in a plumoreticulate fashion in the elaborate specimen, but largely plumose in thin crusts. The tracts fan out near the surface into thinner tracts 20–40 µm in diameter. The ectosomal skeleton ( Fig. 97c ) is of the aegogropila-type with intercrossing thicker (40 µm thick, 5–8 spicules across) and thinner (20 µm thick, 2–3 spicules across) forming a neat reticulation with meshes of 150–200 µm in widest extent. Microscleres are scattered between the ectosomal tracts and in the interior. No rosettes.

Spicules ( Figs 98 a–d). Mycalostyles, two overlapping categories of naviculichelae, sigmas. It is likely that the two sizes of naviculichelae conform to anisochelae II and III of other members of the subgenus.

Mycalostyles ( Figs 98a,a 1 ), robust, straight, with prominent heads and pointed opposite ends, 324– 407.6 –478 x 5– 8.9 – 15 µm.

Anisochelae I (= II) ( Figs 98b ), usually rare, occasionally absent, naviculichela-shape, robustly rounded in outline, two sides shaped slightly different, lateral alae well-developed, 22– 29.8 – 36 µm.

Anisochelae II (= III) ( Figs 98c ), dominant, naviculichela-shape, oval in shape, with inner plate and median alae in various stages of closure, 13– 14.8 – 18 µm.

Sigmas I ( Fig. 98d ), thin, symmetrical, with slightly incurved endings, not obviously divisible in size categories, 11– 18.9 – 33 µm.

Distribution and ecology. Indonesia, Seychelles, West Australia. In deeper parts of reefs and on sandy bottoms, 8–55 m depth.

Remarks. Along with M. (N.) microxea Vacelet et al., 1976 (cf. below), this species stands out among Mycale (Naviculina) members by the absence of ‘normal’ anisochelae I. The chelae comprise only naviculichelae in a wide size range, divisible into two overlapping size categories, which are also slightly different in shape. There are no previous descriptions of the habitus of this species, as the only extant type material is a slide in the Natural History Museum, mentioned for the first time in Bowerbank (1864) (p. 252), and redescribed by Hajdu (1999). All specimens listed above under Material examined are proposed to belong to M. (N.) cliftoni , and these include next to thin crusts also elaborate upright branches.

There is some variability among the specimens in the abundance and sizes of the microscleres. The range in sizes and overlap of larger naviculichelae and the smaller ones in some specimens, with the larger naviculichelae rare and/or barely different in size make distinction between two categories not obvious. Sigmas may be abundant or more rare, and extremely small or large ones are often rare or absent. The limits of variation of the present species remain to be further established.

In view of the lack of normal-shaped chelae, it could be argued, that this species only has anisochelae II and III, and lacks anisochelae I, because the normal-shaped anisochelae in the remaining species are always the largest anisochelae.

Figures

FIGURE 1. A. Numbers of available specimens for the present study from the collections of the Naturalis Biodiversity Center distributed over Indo-West Pacific Marine Ecoregions (MEOWS, cf. Spalding et al. 2007). B. Ditto for type specimens and additional specimens from other institutions consulted for this study.

FIGURE 97. Mycale (Naviculina) cliftoni (Gray, 1867), habitus and skeleton, a, ZMA Por. 12659, preserved encrustation on oyster shell, from Amirantes, Seychelles, b–c, ZMA Por. 11188, from Aride Island, Seychelles, b, habitus on deck of branched specimen, c, light microscopic image of ectosomal skeleton.

FIGURE 98. Mycale (Naviculina) cliftoni (Gray, 1867), ZMA Por. 12659, SEM images of spicules, a, mycalostyle, a1, details of mycalostyle, b, naviculichelae I from front and side, c, naviculichelae II in various stages of closure (all naviculichelae same scale), d, sigma.