A new species of Tethycometes Sara 1994 (Porifera: Hadromerida: Tethyidae) from Singapore

Abstract

Eight species of stalked tethyids have been described previously from the tropics (Sarà & Burlando, 1994; Van Soest et al., 2005; Sarà, 2002). These stalked species are now placed in three genera, namely, Halicometes Topsent, 1898, Burtonitethya Sarà, 1994, and Tethycometes Sarà, 1994. The three genera are distinguished principally on the relative length of the stalk in relation to the size of the hemispherical body which is attached to one end of the stalk (Sarà, 1994, 2002; Sarà & Burlando, 1994). Members of the genus Halicometes have stalks between two and four times the length of the body. Six species have been described from depths of 150–2100 m in the Atlantic and Indo-Pacific regions (Sarà, 2002). In contrast, the monotypic Burtonitethya is characterized by a short stalk that is only as long as the subspherical body. The type species B. gemmiformis Sarà, 1994 was described from the Andaman Islands from an unknown depth (Sarà, 1994, 2002). More recently, specimens collected off Java in 1900 at a depth of 82 m and possessing a long stalk eight times the length of the ovoid body were designated as type species for Tethycometes (see Sarà, 1994, 2002). This paper describes a new species of Tethycometes dredged from waters less than 15 m deep off the coast of Singapore Island, Southeast Asia. With a long stalk eight times the length of its ovoid body, it is the second species to be assigned to the recently erected genus Tethycometes. It differs from the type species T. sibogae Sarà, 1994 in the presence of oxyspherasters which form a thin but distinct cortex. It also differs from all other stalked tethyids in having a partially detached tangential skeleton surrounding the stalk, as well as in possessing rooting processes emanating from the basal half of the stalk.