Ptenothrix koreanensis, Jo & Park, 2023

Jo, Seon Hwa & Park, Kyung-Hwa, 2023, A new species of Ptenothrix Börner, 1906 (Collembola, Symphypleona, Dicyrtomidae) from South Korea, Zootaxa 5301 (1), pp. 124-136 : 126-133

publication ID	https://doi.org/ 10.11646/zootaxa.5301.1.6
publication LSID	lsid:zoobank.org:pub:D885CF47-0FE1-48D5-AEEA-60A0F954E853
DOI	https://doi.org/10.5281/zenodo.8016550
persistent identifier	https://treatment.plazi.org/id/03AB5E67-186A-D17A-FF0F-FD3982D316F7
treatment provided by	Plazi
scientific name	Ptenothrix koreanensis
status	sp. nov.

Treatment

Ptenothrix koreanensis sp. nov.

(Korean name: hankuk-doong-un-toktogi)

Figs 1–8 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 , Table 1 View TABLE 1

Type material. Holotype on slide (P-f 69-1): female, “ South Korea, Deoktae Mountain (35°40'58"N, 127°26'34"E), Baegundong-ro, Baegun-myeon , Jinan-gun , Jeollabuk-do Province ”, 3.VII.2021, leg. SH Jo, IA Lee and GD Chang. GoogleMaps Paratypes on slides: 3 females and 3 males, same data as holotype GoogleMaps .

Diagnosis. Head totally black, except for the mouth and median milky white areas. Large and small abdomens dorsally milky whitish, each area surrounded by black. Ventral abdomen totally milky white. Ant. III with 8 subsegments. Chaetae on eyes patches 2+2, long f and very short o acanthoid chaetae. Acanthoid chaetae formula at median area of the clypeal area as 1, 1, 2, 2, 1, 3, plus 2 ov (between lines c and d). Prelabral and labral regions with 6, 5, 5, 4 chaetae. Whorl II of Tib. I with only one ov (as O2ae). Chaetae mps1, 2, 3 and ms1 on small abdomen of the female all smooth and long. Chaetae as1 and as2 blunt and long acanthoid. Dorsal dental chaetae Ⅰi, Ⅰpi–VIIpi and Ⅰpe–VIIpe fringed, but Ⅰe smooth. Retinaculum with 4 chaetae on the corpus. Rami tridentate.

Description. Body length (head + trunk) of type series ranging between 1.0–2.0 mm in females (4 specimens) and 1.0–1.8 mm in males (3 specimens), holotype with 1.5 mm. Habitus as in Fig. 1 View FIGURE 1 . Head totally black, except for the mouth and median milky white areas. Large and small abdomens dorsally milky white, but each area surrounded by black pigment. Ventral abdomen totally milky white.Antennae milky white, but Ant. III proximally dark and Ant. IV blackish. All legs, VT and furcula milky white.

Anterior head ( Fig. 2 View FIGURE 2 ). Eyes 8+8, plus 2+2 interocular acanthoid chaetae (a long f and a very short o); frontal area with three lines A, D, and E, all with acanthoid chaetae of different sizes, line A with 2 (a and b), line D with 3 (c, d and e), line E with 3 (back head chaetae g, h and i) acanthoid chaetae on each side, respectively; interantennal area with three lines (α, β and γ) with 2, 2 and 1 short acanthoid chaetae on each side, respectively. Clypeal area and labrum ( Figs 2–3 View FIGURE 2 View FIGURE 3 ). Clypeal area a–f lines with 5, 5 (+1), 6, 4, 3 (+1), 5 (+1) chaetae or sensilla on each side, respectively: a line with a total of 10 regular chaetae; b line with 3 acanthoid chaetae, 4 f and 4 regular chaetae; c line with 2 acanthoid chaetae, 4 f and 6 regular chaetae; d line with 2 acanthoid chaetae, 2 f and 4 regular chaetae; e line with 1 acanthoid chaeta, 2 f and 4 regular chaetae; f line with 1 acanthoid chaeta, 4 f and 6 regular chaetae; plus one acanthoid chaeta (between rows b and c) and 2 ov (between rows c and d). Prelabral and labral region with chaetae pattern as 6, 5, 5, 4 ( Fig. 3 View FIGURE 3 ).

Antennae ( Fig. 4 View FIGURE 4 ). Ant. Ⅰ with 7 regular chaetae ( Fig. 4A View FIGURE 4 ); Ant. II with 3 ƒ and 19 regular chaetae ( Fig. 4A View FIGURE 4 ); Ant. III with 8 subsegments, basal part with 2 small acanthoid chaetae (Ba, Bi) plus 4 ƒ (Bae, Bai, Bp, Be), apical part with 4 ƒ (Aa, Ap, Ae, Ai) plus an apical organ with 2 cm, and with about 77–79 regular chaetae ( Fig. 4B View FIGURE 4 ); Ant. IV with four subsegments, 3 bc and 2 cm in the apical area, respectively, plus 1 css and 1 msh (above css) in the subapical area, plus about 58 regular chaetae ( Fig. 4C View FIGURE 4 ).

Leg I ( Fig. 5A View FIGURE 5 ). Epicoxa, subcoxa and coxa with 0, 1, 0 regular chaetae, respectively; trochanter and femur: trochanter with 4 regular chaetae; femur with 12 regular chaetae, plus 2 ov and 1 microsensillium, f absent; tibiotarsus: F region with 3 primary FP chaetae (FPe, FPpe, FPae) and 2 secondary chaetae (FSa, FSpe↓), FPe as f; whorls II–Ⅴ with 8 primary chaetae, respectively; whorls II and III with 1 ov each (O2ae, O3ae), whorl IV with 2 ov (O4ae, O4pe), whorls III, IV and Ⅴ with 1 f (IIIe, IVe, Ve), whorls III and IV with 1 additional secondary chaeta on each (3a and 4a respectively); whorl Ⅰ with 9 chaetae, Ja curved.

Leg II ( Fig. 5B View FIGURE 5 ). Epicoxa, subcoxa and coxa with 1 small acanthoid chaeta, 1 regular chaeta and 3 regular chaetae, respectively; trochanter and femur: trochanter with 5 regular chaetae; femur with 13 regular chaetae plus 2 ov, 1 microsensillium and 1 f; tibiotarsus: F region similar to Tib. I; whorls II–Ⅴ with 4 f (IIe, IIIe, IVe, Ve), whorls II–IV with 4 ov (O2ae, O3ae, O4ae and O4pe) with 3 additional secondary chaetae (2a, 3a, 4a); whorl Ⅰ similar to Tib. I.

Leg III ( Fig. 5C View FIGURE 5 ). Epicoxa, subcoxa and coxa with 1 small acanthoid chaeta, 1 regular chaeta and 4 regular chaetae, respectively; trochanter and femur: trochanter with 6 regular chaetae; femur with 12 regular chaetae plus 2 ov, 1 microsensillium and 1 f; tibiotarsus: F region similar to Tib. I; whorls II–Ⅴ with 4 f (IIe, IIIe, IVe, Ve), whorls II–IⅤ with 4 ov (O2ae, O3ae, O4ae and O4pe), with 4 additional secondary chaetae (2a, 3a, 4a and 4i); whorl Ⅰ similar to Tib. I.

Unguis I–III with 1 small basal and 2 large distal inner teeth, tunica absent, lateral lamella without teeth, pseudonychia lateral margins serrate with three basal and two distal teeth; unguiculus I–III with 1 basal inner tooth, subapical filament reaching the tip of unguis, weakly knobbed. Pretarsus with 1 anterior and 1 posterior chaetae on each leg ( Fig. 5 View FIGURE 5 ).

Large abdomen ( Fig. 6 View FIGURE 6 ). Th. II with 1 small acanthoid chaeta at row a and 1 microsensillium at row m; Th. III with 1 blunt acanthoid chaeta and 1 regular chaeta at row a, 2 blunt acanthoid chaetae and 1 microsensillium at row m; Abd Ⅰ with 1 microsensillium at row a, 2 blunt acanthoid chaetae, 1 regular chaeta and 1 microsensillium at row m, 1 small acanthoid chaeta at row p; Abd. II–Ⅴ with Bothr. A with 2 accessory small acanthoid chaetae (a1, a'), Bothr. B with a thin b1 accessory regular chaeta, Bothr. C with c1 and c2 accessory regular chaetae, Bothr. AB> BC, A inserted in a conspicuous papilla. Posterior dorsal complex with dⅠ, dII and dIII rows with 18, 9, 10 small acanthoid chaetae, respectively, Bothr. D with 1 accessory f, plus 3 regular chaetae at row a and 2 regular chaetae at row p; parafurcal area with smooth regular chaetae and 2 f. Retinaculum with 4 chaetae on corpus, rami tridentate.

Small abdomen. Female ( Fig. 7A View FIGURE 7 ). Dorsal anal valve primary chaetae: as1–2 as blunt large acanthoid, as3 as regular, as4–5 as f, ms1 as regular, ms2 as blunt large acanthoid, ms3 as s, ms4 as blunt large acanthoid, and ps1 and ps2 as thin regular chaetae; secondary chaetae: mps1–3 as long regular, mps4 as blunt large acanthoid, and mps' as a regular chaeta and as long as as3. Ventral anal valve primary chaetae: ai1 as f, ai2 as anterior “ s ”, ai3–ai6 as regular chaetae, mi1 as blunt spiny and as long as mps4, mi2 as posterior “ s ”, mi3–4 long and thicker than mpi1–2, mi5 (subanal appendage) thicker than mi3–4 and curved dorsally, and pi1–3 as thin chaetae; secondary chaetae: aai1, ami1, ami3 as regular chaetae plus one ami2 as ov and 1 extra regular chaeta beside ami2.

Small abdomen. Male ( Fig. 7B View FIGURE 7 ). Dorsal anal valve primary chaetae similar to those of the female; secondary chaetae: mps1 thinner than the one of the female, mps4 as a blunt large acanthoid, mps2–3 and mps' absent. Ventral anal valve primary chaetae similar to those of the female, but mi3–4 and pi1–3 thinner than those of the female, mi5 weakly spiny; secondary chaetae: aai1, ami1, ami3 as regular chaetae plus 1 ami2 as ov, extra regular chaetae beside ami2 absent.

Furca ( Fig. 8 View FIGURE 8 ). Manubrium with 9+9 dorsal chaetae. Dens with 25 dorsal chaetae, Ⅰi and Ⅰpi–VIIpi fringed, but VIIIpi smooth; Ⅰpe–VIIpe fringed, but Ⅰe smooth. Bpi, Bp, Bpe, 1p–4p all smooth; ventral side with 8 chaetae, ventral chaetae formula as 3, 2, 1, 1 ... 1 from the apex to the basis ( Fig. 8 View FIGURE 8 ). Mucro without chaeta, dorsal side with about 28–33 inner and 28–37 outer teeth ( Fig. 8 View FIGURE 8 ).

Etymology. The species was named after the country ( Korea) where it was collected.

Habitat. The new species was collected from litter and soil mass of a coniferous forest dominated by the Korean pine Pinus koraiensis Siebold & Zuccarini.

References to each species: (1) Yosii & Lee (1963), (2) Yosii (1965).

Remarks. Ptenothrix koreanensis sp. nov. has a similar color pattern, with the body with a pale dorsal area, compared to P. ciliophora Yosii & Lee, 1963 and P. saxatilis Yosii & Lee, 1963 from Korea, and P. higashihirajii Yosii, 1965 from Japan. However, several other characters are different between these taxa ( Table 1 View TABLE 1 ). The new species differs from P. ciliophora and P. saxatilis in the color pattern of the large abdomen (without longitudinal stripes in P. koreanensis sp. nov. ( Fig. 1 View FIGURE 1 ) vs with longitudinal dorsal black stripes in the other two possibly related species). Other noticeable differences between them are the number of median spiny chaetae on the clypeal area of head (1, 1, 2, 2, 1, 3 in P. koreanensis sp. nov. vs 1, 1, 2, 2, 1, 1 in the other related two species), prelabral and labral chaetotaxy (6, 5, 5, 4 in P. koreanensis sp. nov. ( Fig. 3 View FIGURE 3 ) vs 6, 5, 3, 4 in the related two species), and the morphology of mps1, 2, 3 and ms1 chaetae on the small abdomen of the female (all smooth in P. koreanensis sp. nov. ( Fig. 1 View FIGURE 1 ) vs all ciliated in the related two species). The body color pattern of this new species is most similar to P. higashihirajii , since it has no extra pigments on the wide pale dorsal area. Apart from this character, these two species can also be separated from each other by ps1 and pi2 chaetae on the small abdomen of the female (thin in P. koreanensis sp. nov. vs blunt and strong in P. higashihirajii ).