Genus Crossonema
Mehta & Raski, 1971
Syn.:
 Neocrossonema Ebsary, 1981
Homogma Siddiqi, 1986
Ogma (Homogma Siddiqi, 1986)
Photo Gallery- Niobrara River
Diagnosis
Genus Ogma. Females 0.29-0.86 mm, with 40-93 annules. Annules round, not lobed, with a continuous fringe of fine or blunt spines on most of body; spines simple, but some in posterior region modified in being bifurcate, knobbed or clubbed.  Cephalic region offset, with two differentiated annules; anterior cephalic annule smooth, crenate or spined.  Lip areas elevated, submedian lobes absent.  Stylet 62-125 um long.  Vulva 3-16 annules from terminus, lips generally pointed.  VL/VB about 0.8-1.1.  Tail conoid-rounded or conoid pointed.  Males with three, sometimes four incisures in lateral field, low bursa and setose spicules.  Fourth-stage juveniles with longitudinal rows of broad scales, each bearing one or more spines.

Type species
    Crossonema civellae (Steiner, 1949) Mehta & Raski, 1971
        Syn.: Criconema civellae Steiner, 1949
              Ogma civellae (Steiner) Raski & Luc, 1987
              Ogma civellae civellae (Steiner, 1949) Raski & Luc, 1987 (Reay & Davies, 1998)
              Criconema celetum Wu, 1960
              Crossonema (Crossonema) celetum (Wu) Siddiqi, 1986
              Criconema eurysoma Golden & Friedman, 1964
              Crossonema (Crossonema) eurysoma (Golden & Friedman) Siddiqi, 1986
              Criconema vishwanathum Edward & Misra, 1966
              Crossonema (Crossonema) vishwanathum (Edward & Misra) Siddiqi, 1986
(Description- Siddiqi, 2000)

DNA Sequences Obtained
Specimen: Collected:
Niobrara SF  Niobrara River