DIAGNOSTIC CHARACTERS

GENUS STEINERNEMA AND NEOSTEINERNEMA

Abbreviations used in diagnoses: IJ = infective juvenile; EP = distance from anterior end to excretory pore; SP = spicule length; D% = EP of MALE divided by esophagus length x 100; E% = EP of IJ divided by tail length x 100; GS% = gubernaculum divided by spicule x 100; SW = spicule divided by anal body width; ABW=anal body width, um=micrometers, T=IJ tail length.

 All adult data are from the first generation

DIAGNOSTIC CHARACTERS

Species names are arranged in descending order of spicule length
Steinernema intermedium
Spicule length=91 um (84-100), IJ length=671 um (608-800), EP= 65 um (59-69), T=66 um (53-74), E%=96, mucron absent, dorsal depression of IJ tail. In male, mele D%=67 (58-76), SW=1.24 (1.03-1.39), GS=0.69 (0.62-0.77), spicule well curved with blunt tip, rostrum prominent, velum large.FIG.SEM,DNA
Steinernema arenarium (=anomalae)
Spicule length= 84 um (81-91), IJ length=1034 um (724-1408), EP=83 um (76-86), T=75 um (64-84), E%=119, hookless spicule with ball-like tip, D%=93 (male), SW=2.10, GS=0.65, in ventral view, cuneus of gubernaculum V-shaped, mucron absent. FIG.SEM,DNA .
Steinernema scapterisci
Spicule length=83 um (72-92), IJ length= 572 um (517-609), T=54 um (48-60), E%=73, in male, male D%=38 (32-44), SW= 2.52 (2.04-2.80), GS=0.78 (0.69-0.84), mucron present; female with large double-flapped epiptygma, and excretory duct with elliptically-shaped structure. FIG.SEM. DNA
Steinernema karii
Spicule length=83 um (73-91), IJ length=932 um (876-982), EP= 74 um (68-80), T=74 um (64-80), E%=96, mucron absent, male D%=66 (53-78), SW=1.50, GS=0.7, spicule well curved with blunt tip, spicule head twice as long as wide, velum thin; gubernaculum with posterior end bifurcate, cuneus present.
Steinernema diaprepesi   (new)
Spicule length=79 um (71-90), IJ length=1002 um (880-1133), EP=74 um (66-83), T=83 um (65-91), E%=89.6 (78-114), spicule head elongate, length/width=1.4-2.0, shaft very short, lamina thick, terminus blunt with longtudinal depression, velum present. D% of male=80 (68-86), SW=1.8 (1.5-2.0), GS=0.69 (0.59-0.79), epiptygma low, double flapped, male terminus without mucron, young female terminus usually with 5 papillae-like structures, dissapearing in fully mature females.   (SEM1)(SEM2) SEM3SEM4
Steinernema puertoricense
Spicule length=78 um (71-88), IJ length=1171 um (1057-1238), EP=95 um (90-102), T=94 um (98-107), E%=101, spicule well curved with tip without a hook, mucron absent, male D%=77, SW=1.52, GS=0.51, double flapped-epiptygma present in females; FIG.SEM.
Steinernema siamkayai
Spicule length=77.5 um (75-80), IJ length= 446 um (398-495) , EP= 35 um (29-38), T= 35.5 um (), E%=96 (85-112), spicule with prominent head, shaft indistinct, rostrum present; gubernaculum slender, tapering gradually posteriorly, male D%=42 (35-49), SW=1.7 (1.4-2.2), GS=0.7 (0.6-0.8) epiptygma present, mucron present.
Steinernema glaseri
Spicule length=77 um (64-90), IJ length=1130 um (864-1448) , EP=102 um (87-110), T=78 um (62-87), E%=131, spicule with prominent shaft and hooked tip, in ventral view, gubernaculum tapering gradually anteriorly, cuneus Y-shaped, male D%=70, SW=2.05 (1.64-2.43), GS=0.71 (0.64-0.85), epiptygma absent, mucron absent. FIG.SEM. DNA
Steinernema longicaudum
Spicule length=77 um (?), IJ length=1063 um (?), EP=81 um, T=95 um, E%=85, hookless spicule tip, male D%=62, SW=1.60, GS=0.62; spicule narrows suddenly to form tip with flattened terminus, epiptygma absent, mucron absent. FIG.SEM.
Steinernema caudatum
Spicule length=75 um, IJ length=1106 um (933-1296), EP=82 um (76-89), T=88 um (80-100), E%=94 (87-100), male D%=71, SW=2.22, GS=0.69. spicule tip truncate, mucron absent; female tail sometimes with 2 projections.
Steinernema thanhi (New)
Spicule length=72 um (67-78), IJ length=851 um (720-960), EP=75 um (68-84), T=63 um (52-72), E%=119 (101-138), male D%=73 (64-82), SW=1.8 (1.5-2.1), GS=0.7 (0.5-0.8), spicule head longer than wide, velum thin, mucron absent.  SEM1SEM2 SEM3
Steinernema oregonense
Spicule length=71 um (65-73), IJ length=980 um (820-1110), EP=66 um (60-72), T=70 um (64-78), E%=100 (90-110), male D%=73 (64-75), SW=1.51, GS=0.79, spicule moderately curved, spicule head enlarged, tapering anteriorly, mucron absent. DNA
Steinernema ceratophorum
Spicule length=71 um (54-90), IJ length=706 um (591-800), EP= 55 um (47-70), T=66 um (56-74), E%=84, male D%=51 (33-65), SW=1.4 (1.0-2.0), GS=0.6 (0.4-0.8), mucron absent in first and second generation, spicule curved with blunt tip, velum large extending nearly to spicule tip, gubernaculum boat-shaped with posterior end bifurcate, cuneus small.
Steinernema loci (New)
Spicule length=71 um (60-80), IJ length=986 um (896-1072), EP=80 um (71-86), T=75 um (66-83), E%=107 (94-120), male D%=73 (61-80), SW=1.9 (1.7-2.1), GS=0.7 (0.5-0.8), spicule head longer than wide, 1/3 of spicule length, tail without mucron. SEM1SEM2 SEM3
Steinernema affine
Spicule length=70 um (67-86), IJ length= 693 um (608-880), EP=62 um (51-69), T=66 um (64-74), E%=94, internal spine in IJ tail, male D%=61, SW=1.17, GS=0.66, mucron present, small. FIG.SEM.
Steinernema feltiae (=bibionis)
Spicule length=70 um (65-77) , IJ length= 849 um (736-950), EP=62 um (53-67), T=81 um (70-92), E%=78, male D%=60, mucron long, tail=81 m, SW=1.13 (0.9-1.30), GS%=59 (0.52-0.62), spicule slightly curved, spicule head twice as long as wide. FIG.SEM. DNA
Steinernema monticolum
Spicule length=70 um (61-80), IJ length=706 um (612-821), EP=58 um (54-62), T=77 um (71-95), E%=76 (63-86), male D%=55 (49-51), SW=1.40 (1.20-1.5), GS=0.60 (0.5-0.7), spicules wide, anterior end rounded, well curved, shaft short but distinct, velum large.
Steinernema ritteri
Spicule length=69 um (58-75), IJ length=510 um(470-590), EP=38 um (32-40), T=51um (44-56), E%=88, mucron absent, male D%=47, SW=1.56, GS=0.64, female with epiptygma.
Steinernema pakistanense (New)
Spicule length = 68 ± 3.6 um (62-73), labial region of IJ bearing two horn-like structures, IJ length= 683±21 um (649-716), EP=54±2.2 um (49-58), T=58±2.1 um (53-62), E%=91±5 (87-102), male D%=60 ± 3 (50-60), SW = 1.8 ± 0.1(1.0-2.2), GS = 0.6 ± 0.04 (0.5-0.6), spicule head elongate, broad not continuous with the blade, tip pointed, velum present, 10% of male with mucron.
Steinernema riobrave
Spicule length=67 um (63-75), IJ length= 622 um (561-701), EP=56 um (51-64), T=54 um (46-59), E%=105, spicule sickle-shaped, spicule head tapering anteriorly, in ventral view, width of neck of gubernaculum large, cuneus Y-shaped, mucron absent, male D%=71, SW=1.14, GS=0.76. FIG.SEM. DNA
Steinernema carpocapsae
Spicule length=66 um (58-77), IJ length=558 um (438-650), EP=38 um (30-60), T=53 um (46-61), E%=66, spicule head wider than long, ventrally projected, spicule tip pointed or bluntly pointed; in ventral view, cuneus arrowhead-shaped or Y-shaped, mucron present, male D%=41, SW about 1.72, GS=0.71. FIG.SEM. DNA
Steinernema bicornutum
Spicule length=65 um (53-70), IJ length=769 um (648-873), EP=61 um (53-65), T=72 um (63-78), E%=84 (80-100), male D%=52 (50-60), SW=2.22, GS=0.72, spicule curved, spicule head typified by ventral projection and a width greater than length, blade well curved anteriorly or at mid region, posterior part slightly curved ot straight, velum present; in ventral view, cuneus arrowhead-shaped, mucron absent. FIG.SEM. DNA
Steinernema abassi
Spicule length=65 um (57-74), IJ length=541 um (496-579), EP= 48 um (46-51), T=56 um (52-61), E%=86, male D%=60, SW=1.56 (1.07-1.87), GS=0.7 (0.58-0.85), mucron absent, spicule curved, velum large.Gubernaculum boat-shaped.
Steinernema kushidai
Spicule length= 63 um (48-72), IJ length=589 um (524-662), EP=46 um (42-50), T=50 um (44-59), E%=92; spicule head truncate or rounded anteriorly, almost as long as wide, blade with large anterior end, rostrum prominent, velum present; mucron absent, male D%=51; SW=1.50, GS=0.70. FIG.SEM. DNA
Steinernema sangi (New)
Spicule length=63 um (58-80), IJ length=753 um (704-784), EP=51 um (46-54), T=81 um (76-89), E%=62 (56-70), male D%=49 ((42-62), SW=1.5 (1.2-1.6). GS=0.6 (0.5-0.7), mucron small, spicule head short, velum large.  SEM1 SEM2 SEM3
Steinernema thermophilum (New)
spicule length=61 um (44-72), IJ length=555 um (510-620), EP=40 um (37-46), T=45 um (40-52), E%=90 (81-102), male D%=63 (50-87), SW=1.7 (1.2-2.8), GS=0.6(0.5-0.7), spicule head short, spicule tip pointed, velum present.
Steinernema cubanum
Spicule length=58 um (50-67), IJ length=1283 um (1149-1508), EP=106 um (101-114), T=67 um (61-77), E%=160, male D%=70, SW=1.40, GS=0.67, spicule head continuous with spicule blade dorsally, spicule tip hookless, in ventral view, cuneus of gubernaculum Y-shaped, velum narrow; mucron absent FIG.SEM.
Steinernema neocurtillae
Spicule length=58 um (52-64), IJ length=885 um (741-988), EP=18 um, E%=23, EP extremely short, T=80 um (64-97), male D%=12, SW=1.43 (1.18.1.64), GS=0.89 (0.82-0.93), spicule short, spicule tip with a prominent depression on ventral side; mucron present, short. FIG.SEM. DNA
Steinernema kraussei
Spicule length=49 um (42-53), IJ length= 951 um (797-1102), EP=63 um (56-66), T=79 um (63-86), E%=80, spicule well or moderately curved, mucron small, male D%=53, SW=1.10, GS=0.67. FIG.SEM.
Steinernema rarum
Spicule length=47 um (42-52), IJ length=511 um (443-573), EP=38 um (32-40), T=51 um (44-56), E%=72, morphometrics of this nematode are less than those of other steinernematids, mucron present, male D%=50, SW=0.94, GS=0.71. Spicules with rounded anterior end, shaft present, sometimes indistinct, velum wide. Gubernaculum thick, cuneus present.
Neosteinernema longicurvicauda
Spicule=61 um (52-67), IJ length=926 ) um (789-1084), EP=68 um (61-76), T=167 um (141-190), E%=41, male D%=44 (30-54), SW=1.03 (0.80-1.50), GS=0.97 (0.84-1.08), male terminus digitate, spicule foot-shaped, 27-29 genital papillae, phasmids large, female tail longer than ABW, IJ tail long, curved, as long as esophagus length. FIG.SEM.

Updated October 2004
This document was constructed and is maintained by KHUONG B. NGUYEN
Entomology & Nematology Department
University of Florida