Similonychiurus, Pomorski, Romuald J., 2007

Pomorski, Romuald J., 2007, Three new genera of Onychiuridae (Collembola), Zootaxa 1461, pp. 49-58 : 49-50

Similonychiurus gen. n.

Type species: Onychiurus (Protaphorura) voegtlini Christiansen & Bellinger, 1980: 386

Diagnosis. Body white, cylindrical and relatively short, without anal spines. Abdominal segments IV–VI fused dorsally. Dorsal side of body with dorsomedial and lateral pseudocelli. Dorsal posterior cephalic pseudocelli present. Ventral pseudocelli absent. Pseudocelli oval and well chitinised, mushroom-like, distinctly protruding above surface of cuticle. Parapseudocelli absent. Furca reduced to the a small convexity with 1+1 setae and two patches of fine granulation, located by sides. Subapical organite present. Antennal III sense organ consisting of 4 guard setae, 4 papillae and simple, stick-like sensory clubs. Postantennal organ with bilobed vesicles. Labial palp modified, with short papillae and dorsal guards apically dilated. Head of maxilla elongated with modified hypertrophic lamellae projecting beyond tip of the reduced spine-like ungulus. Dorsal chaetotaxy oligochaetotic. Dorsal setae apically pointed, poorly differentiated into macro-, meso-, and microsetae. Sensilla on the body distinct. Head without d0 seta. Tibiotarsi with 11 distal setae. Male ventral organ absent.

Etymology. The genus name is derived from the Latin word “similis”––similar.

Discussion. Because the presence of a functional furca, pigmented body and an unusual maxilla Stach (1954) create the subfamily Lophognathellinae with one genus and species Lophognthella choreutes Börner, 1908 . This taxonomic step was supported by Fjellberg (1998/99) which drew attention to large difference between Lophognathella and other onychiurids, especially in labial structure and the general body shape. Ussuriaphorura pluripseudocellata ( Martynova, 1979), like Lophognathella , has a strongly modified maxilla, pigmented body and efficient furca and is therefore transfered to the subfamily Lophognathellinae. The type species of Similonychiurus gen. n. also has the same type modification of the labial palp and the maxillary head like Ussuriaphorura. These characters undoubtedly locate the two genera to the subfamily Lophognathellinae, but Similonychiurus takes an isolated position within the subfamily due to the reduced furca and lack of pigment. In addition the structure of the pseudocelli is exceptional, being unique among Onychiuridae .