Spi 

 C 



COBB: A KEY TO THE GENERA OF FREE-LIVING NEMAS 475 



Ovary 1, anterior; cephalic setae or minute 

 Gonad 9 outstretched 



Pharynx long, tubular, base halfway to nerve ring: spear none; median bulb . . Gymnolaimus Cobb 1913 

 Pharynx base J distance to nerve ring; spear reduced; oes. bulb strong (Aphelenchoides Fischer 1894) 



( = Seinura Fuchs 1931 

 =Parasitaphelenchus Fuchs 1930 



Gonad 9 renewed -Pathoaphelenchus (Cobb) Steiner 1931) 



Median oesophageal bulb present 



Pharynx wide as long; cardiac bulb not valvate, median valvate; bursa none. .Lycolaimus Rahm 1928 

 Pharynx much longer than wide; cardiac bulb valvate; bursa present ............. Rhabditis Duj. 1845 



( = Diploscapteroides Rahm 1928 

 =Pseudorhabditis Kreis 1929) 



Median oesophageal bulb absent; in soil and fresh water 

 Cardiac swelling long, non-valvate; pharyng. rods heavily cuticular ____ Diphtherophora de Man 1880 



( = Chaolaimus Cobb 1893 

 = Archionchus Cobb 1913) 



Cardiac bulb valvate, preceded by isthmus, i.e. oesoph. cephaloboid; pharyng. rods none 

 Head end lobed by 6 large biting lips or odontia; carnivorous ........... (Teratocephalus de Man 1876) 



Head end not lobed, exc. in Acrobeles insubricus 



Pharynx wall simple.forming 2 chambers ;onchium oft present;ceph.set.O-4 Macrelaimus Maupas 1900 

 Pharynx wall of a longitudinal series of elements, i.e. cephaloboid 

 Probolae on head none ................................................... Panagrolaimus Fuchs 1930 



Probolae on head in 1 or 2 circlets 

 Circlets of probolae 2, elements often elaborate ................................ Acrobeles Linst. 1877 



Circlet of probolae single ..................................................... Cephalobus Bast. 1865 



( = Acrobelmdes (Cobb) Steiner & Buhrer 1933) 

 Ovaries 2; cephalic setae 0, exc. in Teratocephalus minute 



Gonads 9 outstretched; ceph. set. 0; phar. tubular, reaching oesoph. bulb; in soil Aulolaimus de Man 1880 

 Gonads 9 reflexed 

 Spinneret present; wings absent; in fresh water and moist soil ............... Rhabdolaimus de Man 1880 



inneret absent 



uticle with prominent tubercles; lip reg. set off by constrict.; ceph. set. with saccate bases 

 Tubercles encrusting dorsal surface; wings broad, thin; in moss .......... Craspedonema Richters 1908 



Tubercles in longitudinal row(s), right lateral; oesophagus rhabditoid ..... Bunonema Jagerskiold 1905 



( = Rhodolaimus Fuchs 1930) 

 Cuticle without tubercles 



Pharynx a long straight tube, \ neck length or more 



Oesoph. short, a muscular bulb only; <? supplements few, ventral, pre-anal Aulolaimus de Man 1880 

 Oesoph. long, of 2 parts; cf supplements paired, post-anal, i.e. diplogastroid 

 Male papillae 9 pairs; gubernaculum sigmoid; labial papillae 16 ............. Myctolaimus Cobb 1920 



Male papillae 10 pairs ; gubernaculum straight ; bursal membrane narrow . . Cylindrogaster Goodey 1927 

 Pharynx not a simple tube, much shorter 

 Oesophagus without median bulb 



Cuticularized rods supporting pharynx; shed cuticle surrounding nema Diphtherophora de Man 1880 



( = Chaolaimus Cobb 1893 

 = Archionchus Cobb 1913) 

 Cuticularized pharyngeal rods none 

 Head end lobed by 6 large biting lips or odontia; carnivorous ........ (Teratocephalus de Man 1876) 



Headend n&t lobed; bursa present ............................................. Rhabditis Duj. 1845 



Oesophagus with median and cardiac bulbs 



Cardiac bulb valvate; median bulb well set off; glottoid apparatus present 

 Wall of pharynx cylindroid; bursa present; cf tail rhabditoid .................. Rhabditis Duj. 1845 



Wall of pharynx convex inward; bursa much reduced; cf tail long, spicate Rhabditoides Goodey 1929 



(=Rhabditella (Cobb) Chitwood 1933) 



Cardiac bulb without valve; median bulb valvate; d" tail setaceous, diplogastroid 

 Pharyng. rods 3, basal bulbs 2, stalked; tail 25-41%; long, striae fine ...... Tylopharynx de Man 1876 



Pharyng. bulbed supporting-rods none; Diplogasterinae 

 Nema with evident longitudinal striation ........................... Diplogaster M. Schultze 1857 



Nema without longitudinal striation 

 Pharynx wide as deep, wa}l of several elements; d" papillae 0(?) ....... Peronilaimus Rahm 1928 



Pharynx tubular, wall entire; d 1 papillae usually 5 pairs ............... Rhabditidoides Rahm 1928 



Amphid known (for alternative see preceding page) 



External amphid not spiral, circular nor elliptical (for alternative see next page) 

 Habitat marine; cephalic setae and spinneret present; amphid crook-shaped, sometimes =tspiral 

 Ambulatory & somatic set. 0; nema not crooked, not narrowed in card. reg. ; ventral arm amph. pr 

 Phar. wide.heavy, 4-5% ;amphid long,4-50% body ;ceph. setae 4,subceph.l2; -9-. - .Pseudolella Cobb 

 Phar. narrow,inconspic.;amph. under 2%;ceph.set.6,subceph.4;annules tiled; '9' Ceramonema Cobb 1920 



(cf. Pselionema Cobb 1933) 



Ambulatory set. forming ventral pre-anal sole; nema S-shape, narrowed in card, reg.; marine; '9' 

 Oesoph. region hardly swollen; card, bulb faint; cerv. striae all alike. . Notochaetosoma Irwin-Smith 1918 

 Oesoph. region swollen, ovoid; oesophageal bulbs 1 or 2; band of cervical striae 

 accentuated, exc. Tristicochaeta falcatum 

 Ventral ambulatory adhesion tubes or setae in 2 rows ......................... Drepanonema Cobb 1933 



( = Chaetosoma Clap. 1863) 

 Ventral ambulatory adhesion tubes or setae in 3 or 4 rows .................. Tristicochaeta Panceri 1878 



( = Draconema Cobb 1913) 

 Habitat not marine 



Spinneret present; ' 9 ', exc. Chronogaster 



Li ps 6, distinct, revplute; pharynx 9%; amphid semicircular; soil about cane roots Anthonema Cobb 1906 

 Lips not revolute; in fresh water 

 Cephalic setae 4; pharynx wider, under 1.5%; '9 ............................... Chronogaster Cobb 1913 



Cephalic setae 0; pharynx long-tubular; tail 25-30% ......................... Rhabdolaimus de Man 1880 



Spinneret absent; cephalic setae or papilloid 



Tail setaceous, 19%;oesoph. with2 bulbs; amph. semicircular; vulva 21%; '9' Aulolaimnidex Micol. 1915 

 Tail not setaceous, under 15%; oesophagus without median bulb, exc. Cheilobu? 



