Protaphorura abscondita, Kaprus', Igor, Weiner, Wanda & Pasnik, Grzegorz, 2016

Kaprus', Igor, Weiner, Wanda & Pasnik, Grzegorz, 2016, Collembola of the genus Protaphorura Absolon, 1901 (Onychiuridae) in the Eastern Palearctic: morphology, distribution, identification key, ZooKeys 620, pp. 119-150 : 120

Taxon classification Animalia Collembola Onychiuridae

Protaphorura abscondita sp. n. Figs 1-9, 58

Type material.

Holotype (female): Russia, Siberia, Krasnoyarsk Territory, Achinsk Province, 7 km from Nazarovo, steppe meadow, soil, ca 400 m alt., 57°02'N, 90°39'E, 14.VII.1987, leg. S.K. Stebaeva (SNHM). Paratypes: 8 males and 10 females, same data as holotype (SNHM - 7 paratypes: 1 male and 6 females, ISEA - 6 paratypes: 5 males and 1 female, MSPU - 5 paratypes: 2 males and 3 females).

Diagnosis.

PAO with 20-23 simple vesicles. Pso formula dorsally 32/033/33343, ventrally 1/000/0000, subcoxae 1 of I–III legs with 1,1,1 pso respectively. Submedial pso a and b on Abd. terga I–II located close together. Psx formula on Abd. sterna: 111100. Th. tergum I with 12 –15+12– 15 chaetae, chaeta m present. Chaetae s' present on Abd. terga I–III. Manubrial field with 12 chaetae in 3 rows. Claw without lateral denticles.

Description.

Holotype (female) length 1.2 mm, length of paratypes: 0.9-1.1 mm (males) and 1.0-1.3 mm (females). Shape of body typical of the genus: cylindrical with strong AS on distinct papillae (Fig. 1). Colour in alcohol yellowish-white. Granulation more or less uniform, distinct. Usually 10-11 grains around each pso.

Antennae approximately as long as head, their base well marked. Ant. I with 10-11 chaetae, Ant. II with 17-18 chaetae. AIIIO consisting of 5 guard chaetae, 5 papillae, 2 smooth sensory rods, 2 straight and granulated sensory clubs, ventro-lateral microsensillum present (Fig. 5). Ant. IV with subapical organite in unprotected cavity without clear cuticular papilla. Microsensillum on Ant. IV in usual position above second proximal row of chaetae (Fig. 2). Ventrally Ant. IV with numerous chaetae (ca. 58-65) (Fig. 3). Ant. IV with 9-11 well-differentiated sensilla (Fig. 2, 3).

PAO of small length with 20-23 simple vesicles (Fig. 7). Labral formula of chaetae: 4/342. Maxillary outer lobe with simple palp, basal chaeta and with two sublobal hairs. Labial palp of type A. Labium with 6 proximal, 4 basomedian (E, F, G, and f), and 6 basolateral chaetae (a, b, c, d, e, e’). Papillae A-E with 1, 4, 0, 3, 3 guard chaetae respectively.

Pso formula dorsally 32/033/33343, ventrally 1/000/0000. Subcoxae 1 of I–III legs with one pso and one psx each. Submedial pso a and b on Abd. terga I–II located close together, i.e. closer than on Abd. tergum III, both set posteriorly to macrochaeta p5. Psx present on Abd. sterna I–IV (psx formula 0/000/111100). Psp formula dorsally 0/011/1111, ventrally 0/111/01m1m1m, coxae with 1 psp each.

Dorsal chaetotaxy rather symmetrical, as in Fig. 1, 4 and 9. Dorsal chaetae poorly differentiated into macrochaetae and microchaetae. Sensory chaetae s distinct on body. On head p2 chaetae on the same level as p1 and p3. Chaetae p6 on head located anterior to pso b. Th. tergum I with 12 –15+12– 15 chaetae, chaeta m present (chaetotaxy type i2-3m). Both Th. terga II and III with lateral microsensilla and with 5+5 or 6+6 axial microchaetae. Chaetae s' present on Abd. terga I–III, on Abd. tergum V present or absent. On Abd. tergum IV in axial area between M2 and P2 macrochaetae located 7- 8 chaetae, medial chaeta m0 present (rarely absent) (Fig. 1). Abd. tergum V usually with 1-2 unpaired microchaeta m0 and p0 (sometimes m0 absent) (Fig. 1). Abd. tergum VI with 1-2 medial chaetae a0 and m0 (often a0 absent). Relative position of prespinal microchaetae usually of subparallel type (Fig. 9). M/s ratio on Abd. tergum V as 10.5 –11.4/9.0– 9.5, (AS = 10). AS 1.2-1.3 times longer than inner edge of claw and 2.9-3.0 times longer than their basal diameter.

Chaetotaxy of ventral side of head as in Fig. 4. Perilabial area with 4+4 a-chaetae (Fig. 4). Postlabial chaetae 5+5 along ventral groove. Th. sterna I–III with 1+1, 2+2, 2+2 chaetae respectively. VT with ca. 7 –9+7– 9 chaetae, and 2 chaetae at base. Chaetotaxy of Abd. sternum IV as in Fig. 8. Furcal rudiment: cuticular fold (located near the middle of sternum) with 2+2 dental microchaetae in 2 rows. Chaetotaxy of manubrial field rather stable: 4 chaetae present in ma-row, 4 chaetae in mm-row and 4 chaetae in mp-row (Fig. 8). MVO absent. Each lateral anal valves with a0, 2a1 and 1-2a2; upper anal valve with chaetae a0, 2a2, 2b1, 2b2, c0, 2c1 and 2c2 (as in Protaphorura jernika , Fig. 58).

Subcoxae 1 of I, II and III legs with 5, 7, 6 chaetae, subcoxae 2 with 1, 5, 5, coxae with 3, 10, 14, trochanters with 11, 11, 10, femora with 17 each, tibiotarsi with four rows of chaetae (distal whorl (A+T)+B+C): 11+8+3, 11+8+3, 11+8+4 chaetae respectively. Claw with very small (rarely without) denticle in 1/2 of inner edge of claw (Fig. 6). Empodial appendage of same length as inner edge of claw, without basal lamella (Fig. 6).

Etymology.

The name of the new species refers to the Latin absconditus (hidden, concealed).

Discussion.

Protaphorura abscondita sp. n. is characterized by a unique formula of dorsal pso: 2+2 posterior cephalic pso, 3+3 pso on Th. terga II and III and Abd. tergum V. Among seven known species with 3+3 pso on Th. terga II and III, the new species is most similar to the siberian Protaphorura tundricola (Martynova, 1976), Protaphorura submersa Kaprus’ & Pomorski, 2008 and Protaphorura merita Kaprus’ & Pomorski, 2008 due to number of pso on Abd. terga. Protaphorura abscondita sp. n. differs from all these species by the 9-11 well differentiated sensilla on Ant. IV. Additionally, it differs from Protaphorura merita by the absence of cauliflower like papilla on the tip of antenna and 1+1 ventral pso in posterolateral position on head. From Protaphorura submersa , the new species differs by having 3 pso on the base of antennae (4(5) pso in Protaphorura submersa ) and from Protaphorura tundricola by relative position of prespinal microchaetae on Abd.6 (distinctly convergent type in Protaphorura tundricola and subparallel type in Protaphorura abscondita ).