Eunapius conifer ( Annandale, 1916 )

Lim, Swee-Cheng & Tan, Koh-Siang, 2013, A First Record Of Freshwater Sponge From Singapore And Redescription Of Eunapius Conifer (Annandale, 1916) (Haplosclerida: Spongillina: Spongillidae), Raffles Bulletin of Zoology 61 (2), pp. 453-459 : 454-456

Eunapius conifer ( Annandale, 1916)

( Figs. 1–6 )

Spongilla (Eunapius) conifera – Annandale, 1916: 51 (no illustration provided)

Spongilla conifera – Annandale, 1918: 203, pl. IX, figs. 3–5; Gee, 1926: 110; 1927a: 3; 1927b: 184; Gee & Wu, 1927b: 8, fig. 9; Gee, 1931: 36; 1932b: 37; 1932c: 54; Sasaki, 1969: 163

Spongilla (Eunapius) conifera – Gee & Wu, 1927a: 258, figs. a–d

Eunapius coniferus – Penney, 1960: 15; Penney & Racek, 1968: 33; Masuda & Satoh, 1989: 80

Eunapius conifer – Van Soest, 2013, World Porifera Database webpage

Materials examined. — Holotype (in ethanol) ZEV 7105 – 6/7, Spongilla (Eunapius) conifera Annandale , mouth of Moo-Too Creek , Tai Hu, Kiang Su Province, China, ‘stn 12’, 5 Dec.1915.

Paratype USNM 21524 (dry material, labeled as Co-Type), Spongilla conifera Annandale , mouth of Moo-Too Creek , Tai Hu, Kiang Su Prov., China , EX. ZEV 7106 /7, Dec.1915 .

Paratype USNM 21524 (slide, labeled as Type and Schizoholotype), Spongilla conifera Annandale , mouth of Moo-Too Creek , Tai Hu , Kiang Su Prov., China, Gee no. 54388 .

ZRC.POR.0274. Singapore , 2 Feb.2007, on concrete wall of canal, Yishun , Singapore

ZRC.POR.0275. Singapore , 7 Jan.2011, on concrete wall of canal, Yishun , Singapore

USNM P0039458 (dry material), Spongilla conifera Annandale , China; Shandong; Qingdao (as Tsingtao), Gist Gee Freshwater Sponge Collection , collection date unknown .

USNM P0040644 (dry material), Spongilla conifera Annandale , China; Jiangsu, Nanjing, Gist Gee Freshwater Sponge Collection , collection date unknown .

Description. — Material from Singapore and Qingdao, China (Gee Freshwater Sponge Collection), are encrusting, typically 5–8 cm wide and 2–3 cm in height ( Fig. 1 ). The type material (ZSI and USNM, Fig. 2 ) from Tai Hu (Tai Lake) near Shanghai are very thin, approximately 1 mm in thickness, growing on the leaf blade of an eel grass, Vallisneria spiralis (Hydrocharitaceae) . It is interesting to note that gemmules occupied a significant volume of the thin sponge. Colour ranged from almost colourless white to green or brown. Consistency of the living sponge was moderately firm and compact but fragile and friable. Surface smooth, hispid under the light microscope. Oscules fairly numerous, mostly 1–2 mm in diameter. Ostia numerous, slightly less than 1 mm in diameter. Subectosomal cavities not common. The dark gemmules were numerous and can be easily seen through the skeleton of the sponge in the field. Ectosomal skeleton undifferentiated; choanosomal skeleton consists of irregular anisotropic paucispicular tracts: primary tracts typically 2–6 spicules thick; secondary tracts 1–3 spicules thick ( Fig. 3 ). Spongin sparse. Oxeas, 210–232.7–255 μm × 7.5–8.8–11 μm, smooth, straight or slightly bent ( Fig. 4A ). Spicules from type material were larger, ranging 180–350 μm × 8–17 μm. Microscleres absent. Gemmules ( Figs. 5 , 6 ) were conical in shape with a flattened subspherical base (250–315–350 μm) in all type material examined. Pneumatic layer present, thickest at the foramen, becoming thinner towards the base and was thinnest at the base of the gemmule. Gemmuloscleres were embedded in the pneumatic layer only around the foramen ( Figs. 5 , 6 ) and were absent on gemmular surface as well as in other parts of the pneumatic layer. Foramen single with a simple foraminal tubule, simple without collar. Gemmular theca tri-layered. Outer layer consists of outlines of pneumatic chambers evident at the gemmular surface. Pneumatic layer 10–100 μm in thickness with regular lines of polygonal chambers. Foramen opening about 25 μm in diameter, foramen tube straight and simple, without collar. Gemmules are singly scattered throughout the body and are most numerous at the base of ( Fig. 3 ). Gemmuloscleres are oxeas measuring 65–81.5–115μm × 2–2.6–3 μm. The oxeas are smooth, straight, sometimes slightly bent, with blunt tips ( Fig. 4B ).

Habitat. Eunapius conifer was fairly common on a concrete wall lining a storm canal at Yishun, Singapore. It could only be found at the upper, non-tidal reaches of the Yishun–Khatib Bongsu storm canal ( Fig. 1 ). Six specimens of this species were observed on the concrete wall of the canal over a threemeter stretch, just below the surface of running freshwater in Jan.2011 about 50 m downstream of the Yishun Pond, where road runoff accumulated. However, repeated observations made along the edge of the pond itself did not detect the presence of freshwater sponges inside Yishun pond. Similarly, no sponges were found further downstream toward the mouth of the canal leading into the Khatib Bongsu mangroves. Despite visiting 17 localities across reservoirs and streams in Singapore, no other specimens of this species was observed.

Figures

Fig. 1. Eunapius conifer individual encrusting on sloping concrete surface of a shallow drain channel in a storm canal in Singapore. Scale bar = 2 cm. Inset shows the drain channel (water depth about 20 cm) inside storm canal (about 10 m wide).

Fig. 2. Eunapius conifer. A, Holotype ZEV 7105 – 6/7 from ZSI showing encrusting sponge on surface of leaf blade of Vallisneria spiralis. B, Paratype USNM 21524 (dry material). C, Paratype USNM 21524 (slide).

Fig. 3. Eunapius conifer (ZRC.POR.0274). Skeletal cross-section, with gemmules scattered at the base. Scale bar = 200 μm.

Fig. 4. Eunapius conifer (ZRC.POR.0274).A, gemmulosclere.Scale bar = 5 μm. B, skeletal oxea. Scale bar = 20 μm.

Fig. 5. Eunapius conifer. A, ZRC.POR.0274, Gemmule viewed from the side to show gemmuloscleres localised around the foramen (indicated by arrow). Scale bar = 60 μm. B, Paratype USNM 21524, smooth gemmuloscleres around foramen (indicated by arrow). Scale bar = 50 μm.

Fig. 6. Eunapius conifer (ZRC.POR.0274). A, Tangentially cut section of the foramen tip to reveal gemmuloscleres embedded around it. Scale bar = 50 μm. B, Magnified view of gemmuloscleres embedded in pneumatic layer around foramen. Scale bar = 30 μm.