adapted from Geraert and Raski, 1987
| 1 | a | Females diovarial | 2 | |
| b | Females monovarial | 5 | ||
| 2 | a | Tail short, subcylindrical, rounded; stylet very long (90-110µm) | Macrotrophurus | |
| b | Tail elongate, attenuated; stylet < 20µm | 3 | ||
| 3 | a | Cephalic framework sclerotized; vulva with lateral membranes; male cloaca with hypoptygma | Antarctenchus | |
| b | Cephalic framework not sclerotized; vulva withithout lateral membranes; male cloaca without hypoptygma | 4 | ||
| 4 | a | Head high, amphidial slit obvious; metacorpus posterior to middle of esophagus | Psilenchus | |
| b | Head low, amphidial slit indistinct; metacorpus anterior to middle of esophagus | Atetylenchus | ||
| 5 | a | Stylet very long (76-104µm) | Tylodorus | |
| b | Stylet long (38-52µm) | Epicharinema | ||
| c | Stylet moderate (22-34µm) | 6 | ||
| d | Stylet short (<22µm) | 7 | ||
| 6 | a | Cuticle with longitudinal ridges | Campbellenchus | |
| b | Cuticle without longitudinal ridges | Gracilancea | ||
| 7 | a | Head with setae | 8 | |
| b | Head without setae | 9 | ||
| 8 | a | Vulva covered by longitudinal flap; male without caudal alae; male cloaca with hypoptygma | Atylenchus | |
| b | Vulva with lateral flaps; male with caudal alae; male cloaca raised | Eutylenchus | ||
| 9 | a | Cuticle with longitudinal ridges | 10 | |
| b | Cuticle without longitudinal ridges | 14 | ||
| 10 | a | Cone about 1/3 of stylet length | 11 | |
| b | Cone almost 1/2 of stylet length | 13 | ||
| 11 | a | Transverse striations not visible through longitudinal ridges | Basirienchus | |
| b | Transverse striations and longitudinal ridges form block (tessellate or areolate) pattern; lateral field with 4 lines | 12 | ||
| 12 | a | Lip region with 2-3 annules, stylet without knobs | Neothada | |
| b | Lip region with 6-7 annules, stylet without knobs | Basirienchus | ||
| 13 | a | Vulva covered by longitudinal flap; stylet 17-19µm | Pleurotylenchus | |
| b | Vulva with lateral flaps; stylet <15µm | Coslenchus | ||
| 14 | a | Cone about 1/3 of stylet length | 15 | |
| b | Cone almost 1/2 of stylet length | 28 | ||
| 15 | a | Head high, with distinct lateral amphid slits | 16 | |
| b | Head variously shaped, amphid slit longitudinal | 19 | ||
| 16 | a | Female body ventrally curved or spiral; female with offset spermatheca and oocytes in multiple rows | Boleodorus | |
| b | Female body straight; oocytes not in multiple rows | 17 | ||
| 17 | a | Tail bent or hook-shaped near tip | Basirienchus | |
| b | Tail more or less straight | |||
| 18 | a | Stylet without knobs, anterior part with wide lumen | Neopsilenchus | |
| b | Stylet with or without knobs, anterior conical with narrow lumen | Basiria | ||
| 19 | a | Head with disc-like structure | 20 | |
| b | Head with smooth contour | 22 | ||
| 20 | a | Head with small disc | 21 | |
| b | Head with large dome-shaped structure | Cucullitylenchus | ||
| 21 | a | Very slender (a=62-76); caudal alae concave posteriorly | Mitranema | |
| b | Less slender; caudal alae rounded | Filenchus | ||
| 22 | a | Very slender (a=60-180); caudal alae lobed | 23 | |
| b | Body width variable; caudal alae rounded if present | 24 | ||
| 23 | a | Head quadrangular; pore-like amphid apertures; body constricted after vulva | Ecphyadophora | |
| b | Head flattened; long amphid apertures; body not constricted after vulva | Ecphyadophoroides | ||
| 24 | a | Cuticle deeply incised | 25 | |
| b | Cuticle not deeply incised | 26 | ||
| 25 | a | Head quadrangular; body striations with zigzag pattern; male without caudal alae | Miculenchus | |
| b | Head flattened; male with caudal alae | Malenchus | ||
| 26 | a | Very slender; indistinct striation; head very flat; long, sinuous amphid aperture | Lelenchus | |
| b | Larger body diameter; distinct striation; head quadrangular; aperture not sinuous | 27 | ||
| 27 | a | Head high with longitudinal amphid apertures lateral; clavate stylet knobs; DEGO > 1/2 stylet length behind knobs | Irantylenchus | |
| b | Head quadrangular; distinct striation; round stylet knobs; DEGO < 1/2 stylet length behind knobs | Filenchus | ||
| 28 | a | Vulva with lateral flaps | 29 | |
| b | Vulva without flaps | 30 | ||
| 29 | a | Lateral field of 2 lines; vagina thin; post-vulval sac short | Allotylenchus | |
| b | Lateral field of 3 lines; vagina thickened; post-vulval sac short | Aglenchus | ||
| c | Lateral field of 4 or 6 lines; vagina not thickened; post-vulval sac long | Cephalenchus | ||
| 30 | a | Lateral field and striations inconspicuous; caudal alae very small | Polenchus | |
| b | Lateral field and striations distinct; caudal alae distinct | Tylenchus |