Description
Female.  Body slightly curved ventrad upon fixation.  Cuticle finely striate, 1.5-2.0 um thick at midbody and 3-4 um thick on tail.  Lateral hypodermal chords occupying ca 33% of body diam. at midbody.  Lateral, dorsal and ventral body pores indistinct.  Lip region truncate, continuous with body or offset by slight depression, ca 2.5 times as wide as high and ca 25% as wide as body diam. at neck base.  Lips amalgamated; labial papillae not protruding.  Amphids stirrup-shaped, amphidal apertures extending ca 50% corresponding body diam. Odontostyle dorylaimoid, ca 1.4 lip region diam. long; its aperture ca 33% of its length.  Guiding ring weak, 'double', fixed ring at 0.86-0.88 lip region diam. from anterior end.  Odontophore simple, rod-like, 1.5-1.9 odontostyle lengths long.  Nerve ring encircling anterior slender part of pharynx at 35-39% of neck length from anterior end.  Expanded part of pharynx occupying 38-46% of total neck length. Cardia elongate conoid, ca one-third as wide as corresponding body diam.  Pharyngeal gland nuclei and their orifices located as follows: DO = 54-55; DN = 56-57; DO-DN = 1.5-2.4; S1N1 = 68-69; S1N2 = 71-72; S2N = 80-81; S2O = 82-83. Genital system amphidelphic; both sexual branches almost equally developed.  Ovary reflexed, 99-219 um long with oocytes arrangedin single row except near tip. Oviduct 39-92 um long, joining ovary sub-terminally.  Sphincter present at oviduct-uterus junction.  Uterine eggs 45-78 x 29-46 um in size.  Vulva transverse.  Vagina extending inwards ca 32-34% corrsponding body diam. Pars proximalis vaginae 10-13 um long with curved walls encircled by musculature; pars refringens vaginae with two goblet-shaped sclerotised pieces, each measuring 6 x 3 um, cw = 10-11 um; pars distalis vaginae short, 1-2 um.  Prerectum 1.6-2.0 anal body diam. long.  Rectum 1.0-1.2 anal body diam. long.  Tail 1.0-2.3 anal body diam. long, tapering abruptly beyond anus, firstly short conoid, than elongate, slightly dorsally bent with the hyaline part covering almost entire elongate portion.  Two caudal pores on each side.

Male
    Copulatory supplements comprising an adanal pair and ten, regularly spaced, ventromedian papillae.  Spicules dorylaimoid, ca 1.6 cloacal body diam. long.  Lateral guiding pieces ca 20% of spicule length.  Prerectum 2.7 cloacal body diam. long, terminating within range of supplements.  Rectum ca as long as cloacal body diam.  Tail short conoid, with bluntly rounded tip, and with a pair of caudal pores on each side.

Type Habitat and Locality
    Litter from secondary forest, Tempisque Conservation Area, Costa Rica.

Diagnosis and Relationships
    Coomansinema brevicauda is characterized by having 1.3-1.6 mm long, robust body; 21-22 um long odontostyle; transverse vulva; female tail short conoid with an elongate dorsally bent projection and male with ten ventromedian supplements.
    The [new] species is closely related to C. oryzae Ahmad, 1994 but differs in having a smaller, comparatively robust body (L = 1.3-1.6 vs 1.71-1.98 mm; a = 21-25 vs 28-31); shorter tail (tail length = 37-75 vs 97-114 um; c = 20-39 vs 17-20; c' = 1.0-2.2 vs 2.4-3.2); in the nature of hyaline part of tail (hyaline part of tail comprising almost entire elongate portion vs hyaline part of tail extending for ca half of the elongated portion); in the absence of a tongue-like structure at the intestine-prerectum junction vs presence of a long, tongue-like structure at the intestine-prerectum junction, and male with longer spicules (61 vs 55-56 um) and comparatively weakly developed and fewer ventromedian supplements (10 vs 12-14).
    The [new] species differs from C. dimorphicauda Ahmad & Jairajpuri, 1989 in the shape of the amphid (vs amphid with duplex fovea); in having a transverse vs longitudinal vulva; longer and differently shaped female tail (vs tail short conoid with a pointed projection at tip), and males with longer spicules (61 vs 48 um) and fewer ventromedian supplements (10 vs 12-15).

(Description- Ahmad & Shaheen, 2004)

Specimens from Costa Rica
    Coomansinema brevicauda (1)
    Coomansinema brevicauda (2)