Comesomatidae Filipjev 1918

Family Comesomatidae Filipjev, 1918

Remarks. The monophyly of the Comesomatidae has been established only by the presence of a spiral amphid of at least 2.5 turns by Lorenzen (1994). However, the Comesomatidae are generally large species,> 1 mm long, with cylindrical body and conico-cylindrical tail. The cuticle usually has transverse rows of punctations of variable size, with or without lateral differentiation and an enlarged/elevated lateral field may be present. Somatic setae run along the length of the body in 4 longitudinal rows. The cephalic region has 6 lips and a 6+6+4 sensilla arrangement. The labial sensilla are papillate, the cephalic sensilla setose and in either one or two rings, the posterior cephalic setae usually longest. Amphids are usually multispiralled and located closely behind the cephalic setae, with the exception of Cervonema in which the cervical region is elongate. The buccal cavity is perhaps the most variable character across Comesomatidae, ranging from small and undifferentiated in Cervonema to having a sclerotized, dilated and conical posterior section with well developed teeth at its anterior margin in Paramesonchium Wieser 1954. The oesophageal lumen is tri-radiate with distinct marginal tubes. Ovaries and testes are paired, opposed and outstretched. The male copulatory apparatus typically comprises arcuate spicules, proximally cephalate and distally acute, and a gubernaculum with or without (usually paired) dorsocaudally directed apophyses.