[ref. ID; 7637 (Khera, 1973)]
Clark (1961) included the genera Alaimus de Man, 1880, Amphidelus Thorne, 1939 and Adorus Thorne, 1939 (the last genus has been considered a doubtful one by him) in the family Alaimidae Micoletzky, 1929. Thorne (1939) considered this family under superfamily Dorylaimoidea (de Man, 1876) Thorne, 1934. Baker (1962) in his work stated "the family Alaimidae does not belong in the superfamily Dorylaimoidea, although formerly placed in this group. However, because of its long association with the Dorylaimoidea it is included here for the possible covenience of those using these lists". Goodey (1963) raised family Alaimidae to superfamily rank whereas Clark (1961) proposed a new suborder Alaimina to include the family Alaimidae. The definition of suborder Alaimina was emended by Clark (1962) by transferring the superfamily Diphtherophoroidea Clark, 1961 from suborder Dorylaimina (de Man, 1876) Pearse, 1936 to suborder Alaimina on the basis of striking similarity in the male reproductive system, in the presence of excretory pore, a poorly delimited, somewhat pyriform, posterior bulb in the oesophagnus, and in not having a pre-rectum and paired anal supplements. He further redefined the suborder Dorylaimina. The present author agrees with Siddiqi and Husan (1967) in not accepting the transfer of Diphterophoroidea under Alaimina because excretory pore has occasionally been reported and posterior oesophageal bulb a regular character encountered in the family Leptonchidae Thorne, sensu Khera (1970), in the suborder Dorylaimina. Further, as stated by Siddiqi and Husain (1967), buccal armature in some of the Dorylaimina is somewhat similar to that of Diphtherophoroidea. In the final analysis the superfamily Diphtherophoroidea thus connected the suborder Dorylaimina with suborder Alaimina. As it cannot be accommodated either in suborder Dorylaimina because of the presence of a single anterior testis, and is not having a distinct pre-rectum and paired adanal supplements, or in Alaimina because of the presence of buccal armature and a small gubernaculum, the superfamily Diphtherophoroidea is raised to the subordinal rank. This suborder is placed in the order Dorylaimida (de Man, 1876) Pearse, 1942. The suborder Alaimina, as defined by Clark (1962), is not accepted.
Chitwood (1937) regarded the family Alaimidae, and Clark (1961) the suborder Alaimina, a member of order Enoplida. The present author, while disagreeing with these authors, agrees with conventional classification by Goodey (1963) in placing suborder Alaimina as well as Dorylaimina under order Dorylaimida as the characters of these two suborders as well as those of Diphtherophorina n. suborder are covered by the definition of order Dorylaimida.
Diphtherophorina (Thorne, 1935) N. Grad.
Diagnosis
Dorylaimida. Stylet (sensu Thorne, 1939 et acut.) is the combined stylet and stylet extensions. Stylet short, stout, elaborate or long, arcuate attenuated. Only tip (i.e., the true stylet) moulted. Amphid aperture ellipsoidal. Oesophagus a slender tube anteriorly but swelling posteriorly and gradually to a pyriform or elongated-conoid basal bulb. Pre-rectum absent; gubernaculum present.