Oligaphorura judithnajtae, Weiner & Paśnik, 2017

Weiner, Wanda Maria & Paśnik, Grzegorz, 2017, Oligaphorura judithnajtae n. sp. from Japan (Collembola, Onychiuridae), Zoosystema 39 (1), pp. 69-73 : 70-73

Oligaphorura judithnajtae n. sp.

( Figs 1 , 2 )

TYPE MATERIAL. — Holotype. ♂: Japan, Shigawatari Do Cave, Akka Iwaizumi , Pref. Iwate, 29.VIII.1990, leg. Yanagisawa ( ISEA) . Paratypes. 1 ♀, 2 juveniles: same data as holotype ( ISEA) ; 1♂: same data as holotype ( MNHN) .

ETYMOLOGY. — The new species is dedicated cordially to our Colleague, Master and Friend – world-renowned collembologist – Judith Najt.

DIAGNOSIS. — PAO with one four-lobed vesicle. Pso formula: 1+22/133/33342 + 1 dorsally, 2/–/1111 ventrally, each subcoxa with one pso. Psx indistinct. Th. tergum I with 6+ 6 chaetae, with some asymmetries (4-7 chaetae). Ms on Ant. IV and III, Th. II and III prominent in size.

DESCRIPTION

Body

Holotype (♂): length 1.12 mm, paratype female: 1.69 mm, paratype males: 1.47-1.66 mm. Shape of body cylindrical ( Fig. 1A ). Colour in alcohol white. Granulation with coarse granules around all dorsal pseudocelli, usually 12 grains around each pseudocellus.

Antennae

Antennae shorter than head. Ant. I with 8 chaetae, Ant. II with 15-16 chaetae. AIIIO consisting of five guard chaetae, five papillae, two smooth sensory rods, two sensory clubs morel-like (internal one straight and smaller, external bent and bigger), lateral s-microchaeta (ms) present ( Fig. 1B, C ). Ant. IV with subapical organite and s-microchaeta in the second basal row of chaetae ( Fig. 1B ).

Postantennal organ PAO with one four-lobed vesicle (two anterior twice longer than posterior ones), located in small cuticular depression ( Figs 1D ; 2A ). Labral formula of chaetae: 4/342. Labium of type AC, 10 (7 long and 4 spiniform) guard setae and 6 proximal setae present ( Fig. 1E ).

Pseudocelli PSO formula dorsally: 1+22/133/33342+1 ( Fig. 1A ); ventrally: 2/–/1111. Psx indistinct. All subcoxae 1 with one pseudocellus. Psp formula dorsally 011/1111, ventrally 111/??? 1 m.

Chaetotaxy

Dorsal chaetotaxy with asymmetry, as in Fig. 1A . Chaetae relatively long and thin, differentiated into macro- and mesochaetae. Sensory chaetae s undifferentiated. Th. tergum I with 6+6 chaetae sometimes asymmetrically with 4-7 chaetae. Th. tergum II and III with prominent lateral microsensilla (ms) = 0.05 mm ( Fig. 2C, D ).Abd. tergum V without medial unpaired chaetae. Abd. tergum VI with two medial chaetae, a0. and p0. AS on small papillae ( Fig. 1A ), reaching in length inner edge of claw.

Th. sterna I-III with 0 +0, 1 +1, 1 +1 chaetae respectively. VT with 8+ 8 chaetae and 2 +2 setae at base ( Fig. 2B ). Male genital plate as in Figure 2E , males without ventral organ.

Furcal rudiment as a very small, finely granulated area with very small cuticular furrow. Chaetotaxy of manubrial field consists of 2 chaetae in ma–row (so-called “dental setae”), 4 chaetae in mm’-row, 4 chaetae in mm-row and 4 chaetae in mp-row (external ones as macrochaetae) ( Figs 1F ; 2G ). Anal valves with numerous acuminate chaetae; each lateral valve with a0 and 2a1; upper valves with chaetae a0, 2b1, 2b2, c0, 2c1, 2c2 ( Fig. 2F ).

Legs

Tibiotarsi I-III with 20 (11 A +T, 8 B, 1C), 20-21 (11 A +T, 8 B, 1-2C) and 19 chaetae (11 A +T, 7 B, 1C), respectively. Femora I, II, III with 17, 16, 14, trochanters I, II, III with 9, 9, 9, coxae I, II, III with 3, 8-11, 9-12, scx 2 I, II, III with 0, 3, 3 and scx 1 I, II, III with 2-3, 3-4, 3-4 chaetae. Claw without denticle. Empodial appendage with small basal lamella, length of empodium 0.6 of inner edge of claw ( Fig. 1G ).

DISCUSSION

The new species is quite exceptional by the presence of ventral pseudocelli on abdominal segments I-IV, the large size of s-microchaetae (ms) on antennae and thoracic terga II and III, by the long, thin body macrochaetae and by the build of furcal remnant (see above).

Only four species in the tribe possess ventral pso on abdominal segments and anal spines: Onychiurus (Oligaphorura) multiperforata Gruia, 1973 and Onychiurus (Oligaphorura) uralica Khanislomova, 1986 , both treated as Micraphorura in Bellinger et al (2016), Dimorphaphorura olenae Weiner & Kaprus, 2014 and O. duocellata Babenko & Fjellberg, 2015 , the only member of the genus Oligaphorura .

All these species differ from O. judithnajtae n. sp. mainly by the build of furcal remnant (four rows of manubrial setae in the new species, in contrast to the three rows in remaining species). Additionally, M. multiperforata is unique by multiplication of dorsal pso, while M. uralica differs from the new species by the dorsal abdominal pso formula (44454 in uralica and 33343 in the new species) and by the number of pso on subcoxae (2,3,3 in uralica and 1,1, 1 in the new species). Dimorphaphorura olenae clearly differs from O. judithnajtae n. sp. mainly by the PAO with one three-lobed vesicle (four-lobed in the new species) and nine setae in distal whorl of tibiotarsi (eleven in the new species).

Oligaphorura judithnajtae n. sp. seems to be most similar to O. duocellata but can be distinguished from that species as the first thoracic segment has one pso (two pso in duocellata ), the presence of one pso on each subcoxae (2,2,3 pso in duocellata ) and by the PAO with one four-lobed vesicle (three-lobed in O. duocellata ).

Figures

FIG. 1. — Oligaphorura judithnajtae n. sp.: A, habitus and dorsal chaetotaxy;B, dorsal side of Ant. IV; C, sensorial elements of AIIIO; D, PAO and anterior cephalic pso; E, labial palp; F, furcal area; G, tibiotarsus of leg III. Abbreviations: see Material and methods.

FIG. 2. — Oligaphorura judithnajtae n. sp.:A, PAO and anterior cephalic pso; B, ventral tube;C, microsensilla (arrow) on thoracic tergum II; D, microsensilla (arrow) on thoracic tergum III; E, male genital plate; F, anal valves; G, furcal area. Scale bars: A, E, 10 μm; B, F, G, 20 μm; C, D, 5 μm.