Similonychiurus voegtlini (Christiansen & Bellinger, 1980)

Pomorski, Romuald J., 2007, Three new genera of Onychiuridae (Collembola), Zootaxa 1461, pp. 49-58 : 50-53

Similonychiurus voegtlini (Christiansen & Bellinger, 1980) ) comb. nov.

Figs. 1–15

Onychiurus (Protaphorura) voegtlini Christiansen & Bellinger, 1980: 386 Type material. Paratypes (mounted on 2 slides; no 5753): 4 males (1 reproductive, 3 unreproductive), 5 females; USA, Oregon, Lane Co., Andrews Experimental Forest, Willamette National Forest; Tullgren extract of epiphytes from Pseudotsuga ; 1976; leg. D. Voegtlin (Illinois Natural History Survey collection).

Redescription. Color white. Length (without antennae): males 0.75 mm, females 0.88–0.90 mm. Body shape cylindrical, short, without anal spines, with distinctly broadened abdominal segments II–III ( Fig. 9 ). Granulation of body surface very fine and uniform.

Antennal bases not demarcated. Antennae nearly as long as head. Antennal segment IV with subapical organite and 2 cylindrical sensilla, dorsal-subapical and internal-subbasal ( Fig. 1 ). Microsensillum on antennal segment IV relatively long in latero-external position, above posterior setae. Antennal III sense organ consisting of 4 guard setae, 4 papillae, 2 stick-like sensory clubs and 2 sensory rods ( Figs. 4, 5 ). Antennal segment III with a small microsensillum slightly below antennal organ III.

Postantennal organ short, in shallow cuticular groove, with 8–9 bilobed vesicles ( Figs. 6, 7 ). Labial palp modified, with all 5 papillae present. Papillae apically pointed and relatively short, only papilla B two times longer than the rest ( Fig. 11 ). Dorsal guards b4, b3, d4 and d3 apically dilated (b4 is the widest). Head of maxilla elongated with modified hypertrophic lamellae, much longer than the spine-like reduced ungulus ( Fig. 12 ). Maxillary outer lobe with two sublobal hairs ( Fig. 10 ). Pseudocelli oval and well chitinised, mushroom-like, distinctly protruding above surface of cuticle ( Figs. 2, 3 and 15 ). Pseudocellar formula: dorsal 22/000/33332, ventrally no pseudocelli; subcoxa I–III each with one pseudocellus. Parapseudocelli absent.

Thoracic terga II and III with lateral microsensilla ( Fig. 14 ). Dorsal chaetotaxy as in Fig. 9 , symmetrical, poorly differentiated into apically rounded macro- and mesosetae and apically pointed microsetae. Body sensilla cylindrical, well differentiated according formula: dorsal 0/011/11001. Ventral tube with 6–7 apical setae on each side, without basal setae.

Furca reduced to a small convexity with 1+1 setae and two patches of fine granulation ( Fig. 13 ). Claw with only a small inner denticle ( Fig. 8 ). Empodial appendage as long as claw, with distinct basal lamella. Male ventral organ absent.

Distribution. Known only from the type locality.

Figures

FIGURES 1 – 9. Similonychiurus voegtlini: 1, antennal segments III and IV; 2, pseudocellus dorsal view; 3, pseudocellus lateral view; 4, antennal III sense organ – sensory clubs and rods; 5, antennal III sense organ – papillae and bases of guard setae; 6, postantennal organ and anterior cephalic pseudocelli; 7, vesicles of postantennal organ, cross section; 8, tibiotarsal chaetotaxy and claw; 9, habitus and dorsal chaetotaxy.

FIGURES 10 – 15. Similonychiurus voegtlini: 10, palp and sublobal hairs of the maxillary outer lobe; 11, labial palp; 12, head of maxilla; 13, furcal area; 14, lateral part of thoracic tergum II, microsensillum and sensillum; 15, abdominal terga IV – VI, chaetotaxy and localisation of pseudocelli.