Two new species of the genus Daptonema Cobb, 1920 (Nematoda: Xyalidae) found in the monospecific Halophila ovalis patches within an intertidal mixed-species seagrass bed on the coast of the Andaman Sea, Thailand

Daptonema hyalocella sp. n. and D. setihyalocella sp. n. are described from the Ban Pa Khlok seagrass bed, Phuket Province, Thailand. These new species are characterized by the epidermal chords consisting of large cells with a transparent appearance, as in D. conicum (Filipjev, 1922) and D. trabeculosum (G. Schneider, 1906). The key characteristics of D. hyalocella sp. n. are the peculiar epidermal chords, loose S-shaped spicules with no proximal cephalation, an indistinct gubernaculum with a lateral piece, and two terminal setae. For D. setihyalocella sp. n., the key characteristics are similar peculiar epidermal chords, but in this case with the L-shaped spicules having proximal cephalation, a distinct gubernaculum with dorsal apophysis and lateral piece, and four terminal setae.