A new species of Ptenothrix Börner, 1906 (Collembola, Symphypleona, Dicyrtomidae) from South Korea Author Jo, Seon Hwa Division of Science Education and Institute of Science Education, Jeonbuk National University, 54896, Jeonju, South Korea. Tel: + 82 - 63 - 270 - 2783, Fax: + 82 - 63 - 270 - 2781. Author Park, Kyung-Hwa Division of Science Education and Institute of Science Education, Jeonbuk National University, 54896, Jeonju, South Korea. Tel: + 82 - 63 - 270 - 2783, Fax: + 82 - 63 - 270 - 2781. text Zootaxa 2023 2023-06-08 5301 1 124 136 http://dx.doi.org/10.11646/zootaxa.5301.1.6 journal article 53766 10.11646/zootaxa.5301.1.6 40ab6982-18c9-47be-8ff8-6f4049b5212a 1175-5326 8016548 D885CF47-0FE1-48D5-AEEA-60A0F954E853 Ptenothrix koreanensis sp. nov. (Korean name: hankuk-doong-un-toktogi) Figs 1–8 , 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. Paratypes on slides: 3 females and 3 males , same data as holotype . 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 . 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. FIGURE 1. Ptenothrix koreanensis sp. nov. habitus of a fixed specimen: A , dorsal view; B , ventral view; C , lateral view. Scale bar: 0.5 mm. Anterior head ( Fig. 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 ). 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 ). FIGURE 2. Anterior head of Ptenothrix koreanensis sp. nov. , axial chaetae are represented by solid circles, extra chaeta is marked with an asterisk, median area is marked with a black line box. FIGURE 3. Prelabral and labral chaetae of Ptenothrix koreanensis sp. nov. FIGURE 4. Antennal segments of Ptenothrix koreanensis sp. nov. : A , Ant. Ⅰ and Ant. II; B , Ant. III; C , Ant. IV. FIGURE 5. Legs of Ptenothrix koreanensis sp. nov. : A , Leg Ⅰ; B , Leg II; C , Leg III. From the apex to the base: trochanters, femurs and tibiotarsi. Antennae ( Fig. 4 ). Ant. Ⅰ with 7 regular chaetae ( Fig. 4A ); Ant. II with 3 ƒ and 19 regular chaetae ( Fig. 4A ); 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 ); 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 ). FIGURE 6. Large abdomen chaetotaxy of Ptenothrix koreanensis sp. nov. , photograph marks the parafurcal area (black arrows indicate the two f ). Leg I ( Fig. 5A ). 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 ). 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 ). 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 ). FIGURE 7. Small abdomen of Ptenothrix koreanensis sp. nov. : A, female; B, male. Asterisk indicates an extra regular chaeta. Large abdomen ( Fig. 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 ). 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 ). 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. FIGURE 8. Furca of Ptenothrix koreanensis sp. nov. , dorsal chaetae are marked with solid circles, ventral chaetae with dotted circles. Furca ( Fig. 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 ). Mucro without chaeta, dorsal side with about 28–33 inner and 28–37 outer teeth ( Fig. 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. TABLE 1. Characteristics of Ptenothrix koreanensis sp. nov. and three possibly related species of the genus.

Characteristics	Ptenothrix koreanensis sp. nov.	P. saxatilis (1)	P. higashihirajii (2)	P. ciliophora (1)
Locality	South Korea	South Korea	Japan	South Korea
Color pattern
head	uniformly black except for a median pale area	uniformly black except for a median pale area	pale, but mottled in the frontal region	brownish, but with black pigments near the mouth
large abdomen	wide pale dorsal area, without extra patterns	wide pale dorsal area, with extra longitudinal stripes	wide pale dorsal area, without extra patterns	narrow pale dorsal area, posteriorly with extra longitudinal stripes
Ratio
Ant Ⅰ: II: III: IV	1: 6: 6.8: 1.5	1: 5.4: 5.7: 1.7	1: 7: 9: 1.8	1: 8: 10: 2
Ⅰe: Ⅰpe (ou1: ou2)	1.4: 1	1.2: 1	1: 1	1: 1
Chaetae formulae
acanthoid chaetae on clypeal area	1 , 1 , 2 , 2 , 1 , 3	1 , 1 , 2 , 2 , 1 , 1	1 , 1 , 2 , 2 , 1 , 3	1 , 1 , 2 , 2 , 1 , 1
labrum chaetae	6 , 5 , 5 , 4	6 , 5 , 3 , 4	6 , 5 , 5 , 4	6 , 5 , 3 , 4
whorls on Ant III	8	?	?	?
acanthoid chaetae on posterior large Abd. (dⅠ–dIII)	19 , 8 , 10	?	?	?
Chaetae
Head
ocular ( f, o )	o much smaller than f	o smaller than f	o as long as f	o smaller than f
Small abdomen (♀)
ms1 (a0)	smooth	ciliated	smooth	ciliated
ms2 (N)	ms2 much smaller than as2	ms2 as long as as2	ms2 much smaller than as2	ms2 as long as as2
ps1 (sa)	regular	regular	acanthoid	regular
pi2	regular	regular	acanthoid	regular
mps’	regular	regular	regular	acanthoid
mps1 , 2 , 3	all smooth	all ciliated	all smooth	all ciliated
ms4 , mps4 (H, T)	ms4 as long as mps4	ms4 much longer than mps4	ms4 as long as mps4	ms4 as long as mps4
Unguiculus
subapical filaments on Ⅰ–III	all weakly knobbed	all knobbed	all swollen	Ⅰ and II acute, obtuse on III
Dens parafurcal area Mucro	all smooth	?	?	?
mucro teeth (outer, inner)	28–33, 28–37	39, 45	28, 37	33, 48

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 ). 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 ) 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 ) 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 ) 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 ).