1 Stoma armed with three odontia situated at juncture of cyathiform and tubular portion of the stoma; interchordal punctuations in circumferential rows................................. 2
1 ' Stoma armed with six odontia situated at juncture of cyathiform and tubular regions of the stoma; interchordal punctuations irregularly distributed (12–14 precloacal suppl.; spic. 101, 2 abd; ov. outstreched) ............. Hopperia hexadentata Hope & Zhang 1995
2 Length of posterior cylindrical region of the stoma larger than 1,5 amphid diameters 3
2 ’ Length of posterior cylindrical region of the stoma smaller than 1,5 amphid diameters (12 precloacal supplements; spicules 44 µm long, 0.5 abd; ov. outstretched)................ ........................................................................................................ H. patagonica n. sp.
3 Length of posterior cylindrical region of the stoma between 1,5 and 2,5 amphid diameters....................................................................................................................................... 4
3 ’ Length of posterior cylindrical region of the stoma larger than 2,5 amphid diameters 5
4 Spicules shorter than or equal to 2.0 abd...................................................................... 6
4 ’ Spicules longer than 2 abd (precloacal suppl. present; Spic. 87.0 µm, 2.5 abd, ov. outstreched).......................................................................... H. muscatensis Warwick 1973
5 More than 10 precloacal supplements (20–21 precloacal suppl.; Spic. 69.0 µm long, 1.5 abd, ov. outstretched ............................................. H. indiana Muthumbi et al. 1997
5 ’ Less than 10 precloacal supplements (8 precloacal suppl.; Spic. 37.0–44.0 µm, 1.5 abd, ov. outstretched).............................................................. H. australis Jensen 1992
6 Tail tip not swollen........................................................................................................ 7
6 ’ Tail tip swollen.............................................................................................................. 8
7 Reflexed ovaries (8 precloacal suppl., spic. 40.0 µm, 2 abd)....................................................................................................................... H. dorylaimopsoides (Allgen, 1959)
7 ’ Outstretched ovaries (6–7 precloacal suppl., spic 54,8 µm, 1,5 abd).............................. ................................................................................... H. beaglense Chen & Vincx 1998
8 Number of precloacal supplements greater than 10 (13–16 precloacal suppl., spic. 52.0–54.0 µm long, 1.3 abd, ov. reflexed) ....................... H. massiliensis Vitiello 1969
8 ’ Number of precloacal supplements smaller than 10 (6 precloacal suppl., ov. outstretched) spic. 54.0 µm, 1.4 abd........................... H. americana Pastor de Ward 1984 spic. 48.7 µm, 1.8 abd ....................................................... H. arntzi Chen & Vincx 1998