Chribellphorura allanae (Christiansen & Bellinger, 1980)

Pasnik, Grzegorz & Weiner, Wanda Maria, 2018, Redescription of Chribellphoruraallanae (Christiansen & Bellinger, 1980) (Collembola, Onychiuridae), with comments on the systematic position of the genus, ZooKeys 803, pp. 1-6 : 3-4

Chribellphorura allanae (Christiansen & Bellinger, 1980) Figs 1-6, 7

Onychiurus (Archaphorura) allanae Christiansen & Bellinger, 1980: 406.

Type material.

Paratype, female (No. Insect Collection 529.3270): USA, Corvallis, Benton Co., Oregon, under loose bark of fir tree, 1967, leg. Fitzgerald, housed in Illinois Natural History Survey, Insect Collection.

Diagnosis.

Pso formula as 32/122/23343 dorsally and 2/000/00000 ventrally; AIIIO with four papillae, four guard setae, two smooth, straight sensory clubs and two smooth sensory rods in the middle, subequal in length to sensory clubs; Abd. sternum IV divided ventrally into two subsegments; Ant. IV with apical vesicle flanked by two papillae; PAO with one five-lobed vesicle; Labium of type 0; Tibiotarsi I–III with 2,3,3 clavate tenent setae.

Redescription.

Length up to 2.0 mm, specimen examined (female) 1.3 mm. Colour in alcohol white (red when alive; Christiansen and Bellinger 1980). Body shape cylindrical, abdomen slightly broadened in the region of Abd. III and IV (Fig. 1). Granulation homogenous.

Antennae thin, shorter than head, not club-like, their base not marked. Ant. I with 10 setae, Ant. II with 16 setae. AIIIO consisting of four papillae, four guard setae, two smooth, straight sensory clubs and two smooth sensory rods in the middle, subequal in length to sensory clubs (Fig. 4), ventro-lateral s-microsetae (ms) present (Fig. 2). Ant. IV with small subapical organite and apical vesicle with two closely flanked papillae (giving the impression of a trilobed vesicle) (Fig. 3) and s-microsetae (ms) located in the middle of the segment (Fig. 2).

PAO with one five-lobed vesicle (5 or 6 lobed; Christiansen and Bellinger 1980), located in a depression with schitinised edges, subequal in length to the nearest pseudocellus (Fig. 5). Seta d0 on the head absent. Labral formula of setae: 4/342. Maxillary palp simple with two sublobal hairs. Labial type 0. Labium with four basal and five basolateral setae.

Dorsal pso formula as 32/122/23343 (Fig. 1), ventrally as 2/000/00000. Abd. terga II–III with pso c located in antero-lateral position (Fig. 1). Psx indistinct. Subcoxa 1 of legs I–III with 1,1,1 pso and 5,5,5/6 setae respectively. Dorsal chaetotaxy asymmetrical, setae relatively short, weakly differentiated into macro- and microsetae. Sensory setae s undifferentiated. Th. tergum I with 4+5 setae. Th. tergum II–III with lateral s-microsetae (ms). Abd. tergum VI with medial setae a0 and p0. Anal spines small and straight, set on small papillae, 0.33 as long as inner edge of claw (Fig. 1). Th. sterna I–III without setae. VT tube with 7+7 distal setae and 2+2 setae at base.

Abd. sternum IV elongated, divided ventrally into two subsegments, below this division with four setae in the middle of segment (Fig. 6). Furcal vestige reduced to field of fine granulation. Chaetotaxy of manubrial field with four setae in ma-row, four setae in mm-row and five setae in mp-row (Fig. 6). Anal valves with numerous acuminate setae, each lateral valve with a0 and 2a1; upper valves with setae a0, 2b1, 2b2, c0, 2c1, 2c2.

Tibiotarsi I–III with 22, 22, 21 setae respectively, distal tibiotarsal whorl with 11 setae (Fig. 7). Distal whorl on tibiotarsi I–III with 2,3,3 clavate tenent setae respectively (Fig. 7). Claw without denticle. Empodial appendage without basal lamella and 0.45 as long as inner edge of claw (Fig. 7).