Mycale (Arenochalina) euplectellioides ( Row, 1911 )

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 : 33-36

Mycale (Arenochalina) euplectellioides ( Row, 1911)

Figs 17 a–d, 18a–f, 19a–e, 28

Esperella euplectellioides Row, 1911: 333 , pl. 37 fig. 12, text-fig. 16.

Mycale euplectellioides ; Burton 1926: 80 (no description); Zoltowska-Aksamitowska et al. 2018: 3, figs 1a–b.

Material examined. BMNH 12.2 .1.58, slide, Red Sea (no locality, likely Sudanese Red Sea) .

ZMA Por. 10996, Jordan, Gulf of Aqaba, coll . T. Fanni, field nr 11, May 1995 (red) ; ZMA Por. 16626, Egyptian Red Sea, Hurghada , 27.2333°N 33.8334°E, depth 7–10 m , SCUBA, coll. Diaa Youssef, field nr. DY–13, 2001 (red); ZMA Por. 16989, Jordan, Northern Gulf of Aqaba, in front of Marine Science Station , 29.5167°N 35.0°E, overgrowing broken parts of Lobophyllia at depth of 10 m , SCUBA, coll. I. K̂tter, field nr. 15.12.1, 15 December 2001 ; ZMA Por. 19757, Egyptian Red Sea, Gulf of Aqaba, coll. Tarek Temraz, field nr. SAA–7, no further data (preserved dry) ; RMNH Por. 9628, Saudi Arabia, near Thuwal, Al Asoul , 22.2654°N 39.0021°E , SCUBA, coll. N.J. de Voogd, field nr. THU07/JED126, 10 November 2014; Specimen not retrieved, not registered, Red Sea, Saudi Arabia, Jeddah , near Marine Station , depth 7 m , coll. D. Youssef, field nr. RS605–50.

Description ( Figs 17 a–d, 18d, 19a–b). Cup-shaped to cylindrical or occasionally club-shaped sponges. In situ color is red or pale red ( Fig. 17a ). Size up to 20 cm high and 10 cm diameter in the type, about 12 x 7 cm in our largest specimen. Surface with deep valleys and sharp conules, the dark red color alternated by white stripes formed by the protruding ends of thick skeletal spiculofibres. Membranes between the conules paler red, soft and somewhat mottled. The rim of cup-shaped specimens is smooth pale red. Preserved specimens loose their tissues quickly by copious slime production, and this process may be responsible for the loss of microscleres which occur loose in the surface membrane.

Skeleton ( Figs 18a , 19c ). System of coarse spongin fibres filled with thicker (<500 µm diameter) or thinner (200 µm diameter) bundles of mycalostyes and with frequent foreign inclusions. Surface membrane flaky, mucous, without spicule skeleton (mostly macerated in preserved specimens).

Spicules ( Figs 18 b–c,f, 19d–e). Mycalostyles, virtually no anisochelae found but reported for type specimen, sigmas.

Mycalostyles ( Figs 18b,b 1 ,b 2 ,e,e 1 ,f, 19d,d 1 ,d 2 ), straight, thin, with wide axial canal, often with trifid heads or elongately rounded, 208– 223.4 –251 x 2– 2.4 – 3.5 µm; type specimen 213– 249.7 –282 x 3.5– 4.3 – 5 µm.

Anisochelae, one anisochela of 15 µm was found in ZMA Por. 16626 (not shown, possibly foreign); they were common in the type specimen ( Fig. 18f ), narrow-shaped, 23– 24.8 – 27 µm.

Sigmas ( Fig. 19f ), strongly curved, usually thin, in a single but variable size, 32– 42.9 – 52 µm; type specimen, 37– 54.2 – 69 µm.

Distribution and ecology ( Fig. 28 ). So far known only from the Red Sea. Row’s type specimen is of unkown Red Sea locality. Our specimens originated from the northern Red Sea (Aqaba, Hurgada, Jeddah). On reefs, depth 7– 10 m.

Remarks. Row’s (1911) description reports the presence of many anisochelae, and we found these in the slide of the type we examined ( Fig. 18f ), but virtually none of the specimens we obtained contained these microscleres.Also the sigmas, reported as common by Row, were quite rare in our specimens. Mycalostyles and sigmas were smaller in our specimens than in the type. These differences with the type would seem sufficient to prevent our specimens to be assigned to the same species as Row’s specimen. However, in specimens of this subgenus elsewhere, e.g. in the Caribbean, the presence of microscleres is notoriously variable and they are not infrequently absent in specimens of the same shape and color. The copious production of slime by specimens lifted out of the water may lead to turning the sponge into an almost macerated stage, and this may well be the cause of considerable loss of microscleres. We are not aware of another vase-shaped Mycale (Arenochalina) species in the Red Sea, so we feel justified to assign our specimens to Row’s species.

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 2. Mycale (Aegogropila) gravelyi Burton, 1937, ZMA Por. 07864 from Ambon Bay, Indonesia, a, habitus encrusting on coral rubble (arrows) (scale bar = 1 cm), b–f, SEM images of spicules, b, mycalostyle, b1, details of mycalostyle, c, anisochela I in side view, d, anisochela II, d1, anisochela II enlarged, e, anisochela III, e1, anisochela III enlarged, f, sigma I.

FIGURE 17. Mycale (Arenochalina) euplectellioides Row, 1911, habitus, a, RMNH Por. 9628 from reefs near Jeddah (photo N.J. de Voogd), b, the same preserved (scale bar = 1 cm), c, the same from above showing vent, d, ZMA Por. 16989 on deck freshly collected in the Gulf of Aqaba (photo Iris K̂tter).

FIGURE 18. Mycale (Arenochalina) euplectellioides Row, 1911, a–c, RMNH Por. 9628 from Jeddah, Saudi Arabia, skeleton and spicules, a, light microscopic image of cross section of skeleton, b–c, SEM images of the spicules of the same, b, mycalostyle, b1, details of mycalostyle, b2, details of trifid head of mycalostyle, c, sigma, d–e, ZMA Por. 10996 from Gulf of Aqaba, d, preserved habitus (scale bar = 1 cm), e, SEM image of mycalostyle, e1, detail of the same, f, holotype of Mycale euplectellioides Row, 1911, BMNH 12.2.1.58, light microscopic images of spicules, including sigmas and anisochelae.

FIGURE 19. Mycale (Arenochalina) euplectellioides Row, 1911, ZMA Por. 19757 from the Egyptian Red Sea, a–b habitus, a, on deck (photo Tarek Temraz), b, preserved (scale bar = 1 cm), c, light microscopic view of skeletal fibre showing coring of mycalostyles and foreign material, d–e, SEM images of spicules, d, mycalostyle, d1, details of mycalostyle, d2, various head shapes of mycalostyles, e, sigma.

FIGURE 28. Mycale (Arenochalina) euplectellioides Row, 1911 and M. (Ar.) regularis Wilson, 1925, approximate distribution of specimens studied (squares) and literature records (dots); blue = M. (Ar.) euplectellioides, red = M. (Ar.) regularis. Squares and dots may represent several close collecting localities.