Rev 01/25/2022
(Compiled from Maggenti, 1981, and lectures by Maggenti in 1992)
| 1 | a |
|
Class: | go to 2 |
| b | Amphid apertures on lips, often difficult to see; no hypodermal glands; hypodermal cells are multinucleate; no caudal glands; male with a single testis and with paired pre-anal supplements, subventral in 2 rows; 3 esophageal glands | Class: | go to 7 | |
| 2 | a | Body without annules; amphid aperture not elaborate - may be large, oval, or stirrup-shaped; 5 esophageal glands | Sub-class: | go to 3 |
| b | Body usually has annules; amphids elaborate, spiral; 3 esophageal glands | Sub-class: | go to 4 | |
| 3 | a | Marine environment; excretory system a single cell; setae on head behind lip region; male with elaborate supplements; esophageal glands open into esophageal lumen anterior to nerve ring, 3 open into stoma | Super-order:
Marenoplica |
go to 5 |
| b | Soil and (rarely) freshwater environment; no excretory cell, have hypodermal glands which may be excretory (except Trichodorus); no head setae; male with delicate supplements; esophageal glands open posterior to nerve ring, opening difficult to see | Super-order:
Terrenoplica |
go to 6 | |
| 4 | a | Female with 1 ovary; prominent circular amphids | Monhysterida | |
| b | Single-spiral or multiple-spiral amphids | Chromadorida | ||
| c | Shepherd's crook-shaped amphid | Araeolaimida | ||
| d | Somatic setae and ornamentation on body | Desmodorida | ||
| e | Somatic setae, ornamentation, and head cap | Desmoscolecida | ||
| 5 | a | Marine and brackish water | Enoplida | |
| 6 | a | Long and slender, soil inhabitants | Isolaimiida | |
| b | Strong, cuticularized stoma, predators | Mononchida | ||
| c | Movable hollow spear | Dorylaimida | ||
| d | Movable tooth | Triplonchida | ||
| e | Esophagus with multiple glands, vertebrate and invertebrate parasites | Stichosomida | ||
| 7 | a | Three-part esophagus (corpus, isthmus and postcorpus), valve in postcorpus; corpus and postcorpus in 12 cells | Sub-class: | go to 8 |
| b | Wine bottle esophagus; large nematodes (many >2.5 cm); all animal parasites | Sub-class: | go to 9 | |
| c | Three-part esophagus with valve in metacorpus (median bulb) and postcorpus glandular | Sub-class: | go to 10 | |
| 8 | a | Male with rays in delicate caudal alae | Rhabditida | |
| b | Male with prominent rays in lobed caudal alae | Strongylida | ||
| 9 | a | Large stoma; most are minor parasites of birds and fish (generally < 2 cm long, except Ascaris) | Ascaridida | |
| b | Collapsed stoma; large nematodes; all use invertebrate for one host | Spirurida | ||
| c | Parasites of terrestrial and aquatic vertebrates with copepods as obligatory secondary hosts | Camallanida | ||
| d | Parasites of annelids and molluscs | Drilonematida | ||
| 10 | a | Very muscular metacorpus; structured glandular postcorpus; movable tooth in stoma; individuals may connect with others at tail tip in water to form a ball of nematodes | Diplogastrida | |
| b | Stoma with buccal stylet | Tylenchida | go to 11 | |
| 11 | a | Dorsal esophageal gland opening (DEGO) in metacorpus; male with rose-thorn spicule and 6 rays in caudal alae | Sub-order: | |
| b | Dorsal esophageal gland opening (DEGO) in procorpus; male with blade-shaped spicule and 0 or 1 ray in caudal alae | Sub-order: |