Mycale (Aegogropila) crassissima ( Dendy, 1905 )

Calcinai, Barbara, Bavestrello, Giorgio, Bertolino, Marco, Pica, Daniela, Wagner, Daniel & Cerrano, Carlo, 2013, Sponges associated with octocorals in the Indo-Pacific, with the description of four new species, Zootaxa 3617 (1), pp. 1-61 : 35-37

publication ID	https://doi.org/ 10.11646/zootaxa.3617.1.1
publication LSID	lsid:zoobank.org:pub:4DCCD152-65DA-44A3-AB19-59811384E1E7
DOI	https://doi.org/10.5281/zenodo.6156093
persistent identifier	https://treatment.plazi.org/id/03B7DE6C-8A0D-F853-FF38-C44AFE1CC1EC
treatment provided by	Plazi
scientific name	Mycale (Aegogropila) crassissima ( Dendy, 1905 )
status

Treatment

Mycale (Aegogropila) crassissima ( Dendy, 1905) View in CoL

( Fig. 22A–H View FIGURE 22. A – I )

Examined material. Sample HL 168: Vietnam, Hang Trai Island, Hang Du II Lake, intertidal, 26 April 2004.

Comparative material: holotype of Mycale (Aegogropila) crassissima Dendy, 1905 BMNH 1907.2.1.56 ( Fig. 22 View FIGURE 22. A – I J-O); holotype of Mycale (Aegogropila) pectinicola Hentschel, 1911 ZMB Por 4404 ( Fig. 31 View FIGURE 31 A-I).

Description. The sponge is rounded, irregularly cushion-shaped, about 20 cm 2 and covers three branches of a colony of Carijoa riisei as a thick mass ( Fig. 22A View FIGURE 22. A – I ). Numerous parts of the branches of the octocoral are free from the sponge, but where the sponge is present it completely covers the octocoral and also the polyp openings. The surface is reticulated and the consistency is firm. The sponge is yellow in situ ( Fig. 22A View FIGURE 22. A – I ) and beige when preserved in ethanol.

Skeleton. The ectosomal skeleton consists of an irregular reticulum of single mycalostyles and tracts of spicules with limited spongin ( Fig. 22B View FIGURE 22. A – I ) and scattered microscleres. In the choanosome ascending tracts of mycalostyles open into fans ( Fig. 22C View FIGURE 22. A – I ). Numerous chelae in rosettes are in the upper part of the tracts.

Spicules. Mycalostyles: slightly curved, with a slightly swollen head and a constricted neck; the axis of the mycalostyles increases in thickness in the middle part of the spicule, which ends with a hastate tip ( Fig. 22D View FIGURE 22. A – I ), 428 – (464.1 ± 23.8) – 495 x 10 – (15 ± 1.3) – 20.5 μm. Anisochelae in two size classes: anisochelae I of usual shape, with upper alae well developed ( Fig. 22E View FIGURE 22. A – I ), 50 – (67.7 ± 6.2) – 75 μm; anisochelae II with reduced alae at one end and a small frontal ala, hook-like, with a small tooth ( Fig. 22F View FIGURE 22. A – I ), 15 – (18 ± 1.1) – 35 μm. This character is clearly visible with SEM. Sigmas “C” shaped ( Fig. 22G View FIGURE 22. A – I ) very thin, 20 – (41.2 ± 8.6) – 52.5 μm. Raphides very abundant, often in trichodragmas ( Fig. 22H View FIGURE 22. A – I ), 22.5 – (24.7 ± 1.8) – 27.5 μm long. Microxeas, smooth, very small (visible only with SEM), up to 2.5 μm long ( Fig. 22I View FIGURE 22. A – I ).

Distribution and remarks. Ceylon ( Dendy 1905 ), Aru Island ( Hentschel 1912), Nicobar and Andaman Archipelagos and Indonesia (Hooper et al. 2000); this species was previously recorded in Vietnam by Dawydoff (1952) and Azzini et al. (2007). Samples were recorded at the intertidal level in a dark tunnel connecting a marine lake in Ha Long Bay to the open sea.

Only three species belonging to the subgenus Aegogropila with raphides are present in the Indo-Pacific area (van Soest et al. 2011): Mycale (A.) pectinicola Hentschel, 1911 , M. (A.) pellucida ( Ridley, 1884) and M. (A.) crassissima ( Dendy, 1905) . The re-examination of the holotype of M. (A.) pectinicola confirmed the presence of isochelae, so that this species has to be moved to the subgenus Zygomycale (see M. (Z.) parishi ). Mycale (A.) pellucida is characterised by very large chelae (about 100 µm) and raphides (60 µm). The spicule complement of our specimen is consistent with Dendy’s (1905) description of M. (A.) crassissima both in shape and size: Dendy (1905) described and illustrated the mycalostyles (490 x 16 µm) with “developed oval heads narrower than the middle of the shaft, from which they are separated by a well marked constriction”. The size of the sigmas and raphides is also similar (36 and 20 x 3.6 µm respectively). The main difference compared to our specimen is in the anisochelae that Dendy (1905) described as belonging to a single category of about 60 x 2.4 µm. The reexamination of its holotype revealed the presence of a second category of anisochelae ( Fig. 22 View FIGURE 22. A – I J) and also of very small microxeas ( Fig. 22 View FIGURE 22. A – I K), both overlooked by Dendy (1905) . These anisochelae II (about 14 µm long) are clearly characterized by reduced alae and by a small frontal ala, with a small tooth; the microxeas are smooth and very small (up to 2 µm long). Additional spicules are mycalostyles (470–520 µm) ( Fig. 22 View FIGURE 22. A – I L), anisochelae I (50–95 µm) ( Fig. 22 View FIGURE 22. A – I M), sigmas (20–45 µm) ( Fig. 22 View FIGURE 22. A – I N) and raphides in trichodragmas (25 µm) ( Fig. 22 View FIGURE 22. A – I O) as reported and illustrated by Dendy (1905) .