Anurida troglodyta sp. nov.

Figs 1–2

Diagnosis. Colour in alcohol creamy white. Body shape slender, elongate. Ocelli absent. Ant IV with 16–17 blunt sensilla and trilobed apical bulb. PAO morel-like with more than 100 vesicles. Mandibles with 5 teeth: 3 apical ones in oblique transverse row, large thin basal one and intermediary tooth. Maxilla with strong, toothed capitulum and 3 serrated lamellae. Chaetom plurichaetotic and clearly differentiated: head with 2 mesochaetae and 4 macrochaetae, Th II–Abd IV without dorsal but with well-developed lateral macrochaetae. Abd IV, ‘sensory chaetae’ s = p4. Abd VI truncated.

Type locality. Hoeokgul (cave) (N37°16´25.8˝ E128°05´39.8˝, 492 m above sea level, 50m long showing vertical morphology), located in Chiaksan (mountain), Seongnam-ri, Sillim-myeon, Wonju-si, Gangwon-do Province, Korea.

Type material. Holotype (male) on slide, 4-vi-2005; 6 paratypes (3 females & 3 males) on slides, same data as holotype; 2 paratypes on SEM stub and 6 paratypes in ethyl alcohol, same locality as holotype; 27.vii.2000, 4.vi.2005, 3.viii.2005; hand collected in dark zone (30m from entrance) of limestone cave by Choi HG leg.

Etymology. The name “ troglodyta ” reflects the species occurrence in deep inside cave. Korean name of the species: Dong-gul-minteok-munui-tok-to-gi.

Description. Body length 3.0– 3.8 mm. Colour in alcohol creamy-white. Body shape slender, elongate (Figs 1 A, 2A, 2D). Paratergites on thorax and abdomen lobed laterally, Abd VI truncated. Body integument with uniform, coarse granulation. Ocelli absent. Ant IV as in Fig. 1 B, with 16–17 curved sensilla; external ms and subapical organite present; trilobed apical papilla present subterminally. Ant III and IV fused dorsally. Sensory organ of Ant III consisting of two sensory pegs, two long, widely separated outer sensilla, and a small ventral ms.

Ant II with 12 chaetae. Ant I with 7 chaetae. PAO morel-like with more than 100 vesicles in a bunch (Fig. 2 C); each vesicle with lots of perforations on SEM photo. Mandibles with 5 teeth: 3 apical ones in oblique transverse row, large basal one and strong intermediary tooth (Fig. 1 C). Maxillary capitulum with 4 teeth and three serrated lamellae: lam.2 longer than capitulum (Figs 1 D, 2B). Labral formula interpreted as 4/2334. Labium with 10 chaetae on each side: apical part with 4 chaetae and 2 small, peg-like sensilla (as in Fig. 4 A). Female genital plate with 18–26 microchaetae; male genital plate with about 34–36 microchaetae. Unguis with inner tooth. Furcal area on Abd IV with a pair of small tubercles with 1 chaeta near the basis.

Chaetotaxy. Dorsal chaetotaxy moderately plurichaetotic (Fig. 1 A), especially on head, thorax and laterally on pleura: the position and numbers of some chaetae varied; macro- and microchaetae well differentiated, head dorsally with 2 mesochaetae and 4 macrochaetae, without dorsal macrochaetae on Th II–Abd IV. Macro- and microchaetae slightly serrated, sensilla smooth. Lateral macrochaetae strongly developed: head with 4; Th I–Th III with 1,1–1,1–1; Abd I–VI with 2,2,2,4,5,6 on each half, respectively. Thoracic tergum I dorsally with 7–9 +7–9 microchaetae and 1 + 1 mesochaetae; thoracic terga II–III with two chaetal clusters each (dorso-anterior and dorsoposterior): thoracic tergum II dorsally with 9–10+9–10 chaetae in DA and 5–6+ 5–6 in DP, ‘sensory chaetae’ s = p3 and m6; thoracic tergum III dorsally with 8+8 chaetae in DA and 5–6+ 5–6 in DP, ‘sensory chaetae’ s = p3 and m6; abdominal terga I–III with 7+7 chaetae between sensory chaetae s (p4); abdominal tergum IV dorsally with 10+10 chaetae, ‘sensory chaetae’ s = p4. Abdominal tergum V, ‘sensory chaetae’ s = p3. Formula of ‘sensory chaetae’ s per half tergum: 022/11111. Lateral microsensilla (ms) present on thoracic tergum II, absent on thoracic tergum III. Tibiotarsi I, II and III with 19, 19 and 18 chaetae, respectively. Ventral tube with 8–9+8–9 chaetae.

Biology. It inhabits dark zone of vertical limestone cave. The cave atmosphere has a relatively constant temperature throughout the year: air temperature ranges from 2 to 7.5? and humidity ranges from 81 to 90 %.

Discussion. A. troglodyta sp. nov. has a morel-like PAO, but has no occelli. Eleven previously described congenera share these characteristics (Jordana et al. 2012). The new species has about 16–17 sensilla on Ant IV, which is more than typical of most species of Anurida, and that can be considered as a troglobiontic character together with big size, multiplication of PAO lobes and specific chaetotaxy with long lateral setae.

A. troglodyta sp. nov. is rather similar to A. plurichaetotica Yosii, 1966 described from a cave of Korea, and A. okamotoi Yosii, 1970 and A. irieti Yosii, 1970 described from caves of Japan, in the presence of differentiated macrochaetae on dorsal area of a head. However this new species clearly differs by size of p1 chaeta on abdominal terga IV or V: small on Abd IV and V in A. troglodyta sp. nov., large on Abd IV and (or) V in three other species. Apart from this, A. troglodyta sp. nov. can easily be identified by characteristic PAO.

Other differences between A. troglodyta sp. nov. and similar species are summarized in Table 1.

Distribution. Korea.