Plakortis bergquistae Muricy, 2011

Pereira, Preeti & Raghunathan, Chelladurai, 2020, New records of Indo-Pacific sponges from the Andaman and Nicobar Islands India, Zootaxa 4894 (4), pp. 81-97 : 93

Plakortis bergquistae Muricy, 2011

( Figures 7 A–G)

Synonymy:

Plakortis bergquistae Muricy, 2011: 311–313 , fig. 7.

Material examined: 2 specimens, ZSI/ANRC–20445, February 20, 2016, B. Quarry, Great Nicobar Island , Coll. Sudhanshu Dixit ; 1 specimen, ZSI/ANRC–20971, July 21, 2018, Rutland Island (site II), South Andaman , Coll. Preeti Pereira.

Description: Thickly encrusting sponge forming cushions, 4 cm in length and thickness up to 2 cm; colour of the specimen dark brown ( Fig. 7A ) when alive and light brown ( Fig. 7B ) in isopropyl alcohol; surface smooth and irregular; consistency soft and compressible; oscules raised when alive, become flush with the surface on preservation.

Skeleton: Ectosome not clearly differentiated from the choanosome; skeleton reticulate, forming irregular/circular meshes, 80–275 µm in diameter ( Fig. 7C & 7D ).

Spicules: Diods and triods; diods abundant, some straight or slightly curved, smooth, thickened at the centre and in two size categories ( Fig. 7E & 7F ). I: 61.0–104.1–169.7 × 2.1–4.2– 6.5 µm; II: 182.5–240.1–315.1 × 5.8–8.1– 10.7 µm; triods smooth, with all actines of equal length ( Fig. 7G ); 20.5–40.5–60.0 × 2.4–3.5– 4.8 µm.

Distribution: This species is reported herein for the first time in Indian waters from the Andaman and Nicobar Islands. The type locality of this species is north Sulawesi in the West Coral Triangle province and has also been described from Western Australia, Northwest Australian Shelf province ( Muricy 2011). The current report extends the distribution of this species to the Andaman province and also the West Indo-Pacific realm.

Remarks: Plakortis bergquistae is the third species of the genus Plakortis to be reported from the Andaman and Nicobar Islands. It differs from its congeners, P. badabaluensis Ubare & Mohan, 2016 (originally described from Badabalu of South Andaman) and P. communis Muricy, 2011 in spicule morphology as the former has a single size category of diods (vs. two size categories of diods based on thickness) while the latter has smaller diods and triods in a size range (vs. larger diods and triods).

Figures

FIGURE 7. Plakortis bergquistae Muricy, 2011 (ZSI/ANRC–20445): A, in situ photograph, B, preserved specimen. C, tangential view of ectosome and choanosome. D, cross sectional view of choanosome. E, F, diods of different sizes. G, triod.