Oceanapia Norman, 1869

Ubare, Vibha V. & Mohan, P. M., 2018, New Records and Range Extensions of Some Marine Sponges (Porifera: Demospongiae and Homoscleromorpha) from the Andaman Islands, India; Part of the Indo-Burma Biodiversity Hotspot., Zoological Studies 57 (3), pp. 1-15 : 8-10

Genus Oceanapia Norman, 1869 Oceanapia fistulosa ( Bowerbank, 1873)

( Figs. 10 and 11 )

Synonyms: Desmacidon fistulosa Bowerbank, 1873 (genus transfer)

Phloeodictyon fistulosum ( Bowerbank, 1873) (genus transfer)

Rhizochalina fistulosa ( Bowerbank, 1873) (genus transfer)

Rhizochalina fistulosa var. infradensata Ridley, 1884 (junior synonym)

Material examined: 2 ex., DOSMB 00176- DOSMB 00177, India: Andaman and Nicobar Islands: North Andaman: Diglipur, Coll. Vibha Ubare, 14.xii.2013.

Description: The shape of the sponge is globular with 7-8 fistules ( Fig. 10A ) apically. The specimen is buried in the sandy substratum. The fistulae are 1.1-3.3cm long and 0.2-0.4 cm in diameter. It is somewhat sturdy. The size of the full specimen is 3.6-4.6 cm. The colour of the sponge is milky white but externally it is fully covered with dark pinkish purple coloured soft coral. Colour remains unchanged after preservation. The fistula shows a circular opening but it is not clear if it has oscules; mostly closed from the upper side. The body of the sponge is porous. The consistency of sponge is hard, incompressible and uneven.

Spicules: Megascleres- It has oxea of two types, one is thick and the other is thin. Thick oxea ( Fig. 10B 1 ) is smooth, robust, slightly curved in the center part of the spicule with a blunt end. It measures 195.0-263.0/4.0-15.0 µm. The thin oxea ( Fig. 10B 2 ) is smooth with pointed ends 87.0- 255.0/3.0-9.0 µm. Microscleres is absent.

Skeleton: The ectosomal skeleton is multilayered and tangentially arranged. The choanosomal skeleton shows multispicular tracts which are arranged in irregular meshes. The section also shows sclerites structure, which from the soft coral ( Figs. 10 C-F).

Habitat: It is attached to rocks. The area is covered by dead corals with several types of algae. The specimen is associated with the soft coral and foraminifera, Elphidium spp.

Distribution: India: Gulf of Mannar ( Carter 1880; Rao 1941; Thomas 1985); the present study observed them in the location at North Andaman - Diglipur; Elsewhere: Aegean Sea ( Kefalas et al. 2003), Banda Sea ( Topsent 1897), Leeuwin ( Bowerbank 1873), Mediterranean Sea - Eastern Basin ( Koukouras 2010), North Atlantic Ocean ( van Soest 2001), Northern Monsoon Current Coast ( Pulitzer-Finali 1993), Western Arabian Sea ( Burton 1959), Western and Northern Madagascar ( Vacelet et al. 1976) Brazil ( Muricy et al. 2011), Eastern Brazil ( Ridley and Dendy 1886), Greater Antilles ( Pulitzer-Finali 1986; van Soest 1980), Indian Ocean ( Thomas 1981), Kenya ( Pulitzer-Finali 1993) and Seychelles ( Thomas 1981) ( Fig. 11 ).

Remarks: Dendy (1905) documented this species from the west coast of Ceylon (Now Sri Lanka); Burton, 1934 and 1959 mentioned this species in the Great Barrier Reef and South Arabian Coast, respectively. Rao (1941) described this species in the Pamban, Gulf of Mannar region. The other species, Oceanapia ascidia (Schmidt, 1870) from the Caribbean region, has also been called Oceanapia fistulosa ( Bowerbank, 1873) , however the spicule size varies (larger oxeas 219-271 × 8.5-14 μm, and smaller oxeas 77- 129 × 3-7 μm) and the habitat consists of soft bottom sediments (van Soest 2017). Further, van Soest (2017) suggested that the use of the name Oceanapia fistulosa ( Bowerbank, 1873) should be restricted to the Indo-West Pacific region specimens.

is absent.

Skeleton: The ectosomal skeleton is absent.

Figures

Fig. 10. Oceanapia fistulosa (Bowerbank, 1873). (A) Specimen after preservation. (B1) Thick Oxea. (B2) Thin Oxea. (C) Longitudinal section. (D) Longitudinal section showing soft coral sclerites. (E) Transverse section showing soft coral sclerites. (F) Transverse section.

Fig. 11. Geographical extension of Oceanapia fistulosa (Bowerbank, 1873).

Fig. 1. Study Area.

Fig. 2. Spheciospongia globularis (Dendy, 1922). (A) Specimen in situ. (B) Specimen after preservation. (C1) Large sized Tylostyles. (C2) Medium sized Tylostyles. (C3) Small sized Tylostyles. (C4) Spiraster. (D) Longitudinal section. (E) Longitudinal section. (F) Transverse section.