Coomansinema istvani sp. n. is described from Ecuador, and is characterised by its relatively small size (L = 0.95-1.51 mm), lip region almost continuous with body profile with partly amalgamated lips, odontostyle slightly sinuate, with wide lumen, 20-27 μm long, female reproductive apparatus didelphic, vulva transverse, pre-rectum very short, mainly in female, 8-9 weakly developed, spaced, ventral pre-cloacal supplements, tail short (c′ = 0.6-1.0), tail convex-conoid in male and cupola-shaped, with a short finger-like process dorsally oriented in female. An updated list of the species of Coomansinema and a key to their identification is also provided. In addition, one new and two known species of Aporcelinus are reported. Aporcelinus altitudinalis and A. seychellensis are described on the basis of more numerous specimens and the male of A. seychellensis is described for the first time; it is similar to the female in general morphology and is characterised by a series of 7-9 spaced ventromedian supplements in addition to the cloacal pair with two supplements in the range of the spicules. Aporcelinus reyesi sp. n. is characterised by a 1.69-1.92 mm long body, lip region truncate, set off by a constriction, lips distinct with prominent papillae, odontostyle straight, with wide lumen, 29-36 μm long, female genital system didelphic-amphidelphic, uterus tripartite, containing up to five small eggs, vulva transverse, 13 male supplements, the last three in the range of the spicules. Tail 1.0-1.5 anal body diam. long, conical with acute tip, ventrally slightly convex, dorsally first convex and then concave, often appearing bent dorsad.