Description of three new Tetranchyroderma gastrotrichs (Macrodasyida: Thaumastodermatidae) from South Korea

Abstract

The present paper deals with description of three new marine gastrotrich species belonging to the genus Tetranchyroderma with a new record for Korea of T. schizocirratum Chang, Kubota & Shirayama, 2002, on the basis of specimens from the Korean coast. Tetranchyroderma anisoankyrum sp. nov. is differentiated from congeners by its dorsal cuticular armature of pentancres with central tine longer than the others, a pair of rod-like cephalic tentacles, 2 cirratum-type TbDL, 13–14 cirratum-type TbL per side, and a pair of TbL. Tetranchyroderma coreense sp. nov. is distinguished from other pentancrous species by cirratum-type tubes of 2 TbDL, one TbL, 3–4 TbVL, paired foot-type TbV, and absence of cephalic tentacles. Tetranchyroderma oblongum sp. nov. is characterized by the character combination of cuticular armature of tetrancres, 7 dorsolateral and 7–9 lateral cirratum-type tubes, and 33–38 TbVL along whole body. This brings the total number of species in the genus Tetranchyroderma known from South Korea to 12.

1. Gastrotricha

“…Europe and North and South America have been sampled more intensively than, for example, Africa, Southeast Asia, or Australia (see Balsamo et al 2008 for more information). Currently, freshwater species are described from Japan (e.g., Suzuki et al 2013) and marine species from South Korean waters (see Lee et al 2013 and references therein); some investigations deal with the Caribbean fauna (e.g., Hummon 2010 or discover the Eastern Mediterranean and the Red Sea (Hummon 2011) or South Africa (Todaro et al 2011b In freshwater species as well as in marine species, some species appear to have a wide distribution, being found in disjunct regions. Currently, freshwater species are described from Japan (e.g., Suzuki et al 2013) and marine species from South Korean waters (see Lee et al 2013 and references therein); some investigations deal with the Caribbean fauna (e.g., Hummon 2010 or discover the Eastern Mediterranean and the Red Sea (Hummon 2011) or South Africa (Todaro et al 2011b In freshwater species as well as in marine species, some species appear to have a wide distribution, being found in disjunct regions.…”

A new gastrotrich species of the genusTetranchyroderma(Macrodasyida: Thaumastodermatidae) from Korea

“…A total of 82 species are currently recognized in the genus Tetranchyroderma, and they are largely adorned with tetrancres (30 species) or pentancres (44 species) (see Lee et al 2013 for details). In the northwest Pacific, 13 species have been reported, which consist of five species with tetrancres (T. dendricum Saito, 1937, T. gracilium Chang, Lee & Clausen, 1998 hoonsooi Chang & Lee, 2001, T. schizocirratum Chang, Kubota & Shirayama, 2002, and T. oblongum Lee, Kim & Chang, 2013), seven with pentancres (T. heterotentaculatum Chang & Lee, 2001, T. monokerosum Lee & Chang, 2007, T. multicirratum Lee & Chang, 2007 aethesbregmum Lee & Chang, 2012, T. megabitubulatum Lee & Chang, 2012, T. anisoankyrum Lee, Kim & Chang, 2013, T. coreense Lee, Kim & Chang, 2013) and a species with triancres and tetrancres combined (T. insolitum Lee & Chang, 2012) (Saito 1937, Chang et al 1998, Chang & Lee 2001, Lee & Chang 2007, 2012Lee et al 2013).…”