During a survey of marine biodiversity in the deep-sea off northeastern Guam, two marine desmoscolecid nematodes belonging to the subgenus Tricoma were discovered. Tricoma (Tricoma) disparseta sp. nov. was described based on specimens collected from sponge and starfish habitats on a seamount at depths ranging from 1300 to 1500 meters. T. (T.) disparseta sp. nov. is distinguished by having 59 to 62 main rings, 9 to 10 subdorsal setae, and 14 to 18 subventral setae on each side. Notable features include the differentiation in length and insertion between subdorsal and subventral setae, and a curved, hooked gubernaculum. The specimen of T. (T.) longirostris observed in this study closely resembles previously reported specimens, characterized by 78 main rings, a long and narrow head shape, 8 to 9 subdorsal setae, 14 to 15 subventral setae, and a gubernaculum with a knobbed apophysis. The morphological characteristics and detailed illustrations of two Tricoma species from the Northwest Pacific Ocean were documented using differential interference contrast microscopy (DIC) and scanning electron microscopy (SEM). Furthermore, pictorial keys and comparative tables are presented for species exhibiting 50 to 64 main rings, aiding in their identification and differentiation.