Genus Isolaimium
Cobb, 1920 (emended)
Photo Gallery- Nine-mile Prairie
Photo Gallery- Arkansas

Diagnosis:  Isolaimiidae new family.  Body elongate (3-6 mm).  Cuticle annulated, at least anteriorly; punctations set in longitudinal and transverse rows (probably always present; sometimes faint or visible only on tail).  Lateral chords faint.  Six hollow tubes surrounding mouth and stoma.  External circle of six large recessed papillae; second circle of six smaller papillae.  Amphids arpparently absent or represented by dorso-lateral papillae of second circle.  Esophagus clavate, with thickened lining.  Stoma long, triradiate, cuticularized, usually with thicker walls near anterior.  Cardia long, cylindrical.  Vulva transverse; female gonads amphidelphic, with flexures.  Male gonads diorchic, outstretched.  Spicules thick, cephalate or non-cephalate, internally divided or not.  Short parallel gubernaculum with two short posterior apophyses.  Preanal, midventral papillary supplements in male.  Large caudal papillae on male tail and fine papillae on female tail.  Tails short, conoid, with bluntly-rounded to pointed tip.

Type species:  Isolaimium papillatum  Cobb, 1920.
(Description- Timm, 1968)

Emended description of the genus Isolaimium (Swart & Heyns, 1991)
Diagnosis:  Isolaimidae.  Body elongate, 3-7 mm.  Cuticle marked with punctations set in longitudinal and transverse rows, forming transverse striae and longitudinal lines over varying parts of the body, depending on the species.  Punctations distinctly visible or faint.  Head sensilla represented by familiar compliment of six inner labial receptors (represented by six tubes), six outer labial papillae, four cephalic papillae and two laterally situated pore-like amphid apertures.  Oesophagus cylindrical to clavate, its lumen minute but with well-sclerotized radii.  Stoma long, tubular, triradiate with sclerotized walls which are thickened towards the anterior.  Cardia long, cylindrical tp pyramidal, dorso-ventral in symmetry.  Seven oesophageal glands observed in one species, number and postition unknown in other species.  Vulva tranverse, female gonads didelphic, amphidelphic.  Male gonads diorchic, outstretched; spicules thick, arcuate to falcate, cephalate or non-cephalate, internally divided or not.  Short gubernaculum has two (or four) apophyses.  Papilloid supplements in male pre-anal, midventral.  Caudal papillae present on tails of both males and females.  Tail short, conoid, with bluntly rounded to pointed tip.

DNA Sequences Obtained
Specimen: Collected:
ARK-10 Washington Co., Arkansas
9 Mile 3-17 BB-01 9-Mile Prairie