Janusius geumgangensis, Dányi, László & Park, Kyung-Hwa, 2016

Dányi, László & Park, Kyung-Hwa, 2016, A new species of Janusius Bretfeld, 2010 (Collembola, Sminthuridae) from the Korean Peninsula, with a key to the species of the genus, Zootaxa 4154 (5), pp. 574-580 : 575-580

Janusius geumgangensis sp. nov.

Figs 1–27

Diagnosis. Ground colour pale yellowish-brown, dark grey dots on head and great abdomen, diffuse grey patches on the ventral part of great abdomen and a darker brown diffuse patch on each sides of it. Each tita with 3 clavate tenent hairs. Retinaculum with 3+3 teeth and 4 chaetae. Circumanal chaetae not winged. Anal appendage thickened chaeta-like, smooth. Mucronal chaeta present, anterior chaetotaxy of dens 3,3,3,2,2,1,1.

Type material. Holotype: female: North Korea, Kangwon Province [Gangwon-do], Mt. Kumgang [Geumgangsan], Onjong-ri , pitfall traps baited with beer in a Pinus densiflora forest, 17– 21.06.1988, leg. Merkl, O.; Szél, Gy.; Lőkös, L. & Szerdahelyi, T. (As-572) (Korea 1988/1338) ( NIBR) . Paratypes: 1 male: Same data as for holotype ( NIBR) ; 2 juveniles: Same data as for holotype ( HNHM coll-934).

Etymology. Named after the Korean name “Geumgangsan”, of its terra typica, Mount Kumgang.

Description. Length 2.85 mm in female, 1.93 mm in male. Habitus and colour pattern in ethanol as in Figs 1– 2 . Ground colour pale yellowish-brown, dark grey dots on head and great abdomen, diffuse grey patches on the ventral part of great abdomen and a darker brown diffuse patch on each sides of it, abd. VI with medial black spot, anal valvae black, dens and distal part of manubrium dark grey, proximal part of manubrium paler, subcoxae and coxae with dark band, ventral side of trochanters and the whole femora dark, each tita with three dark rings. Long chaetae both on great and small abdomen.

Head. In male with one pair of humps on frontal area. Postantennal chaeta (A2) normal in female, a bit thickened and spine-like in male ( Fig. 4 and Fig. 3 respectively). Antennal ratios: 1:1.55:1.65:6.90 in male, 1:2.5:3.55:8.55 in female. Ant. I with four mesochaetae on anterior and three microchaetae on posterior side. Ant. IV with 23 subsegments in female and 24 in male, without additional posteroventral chaetae ( Figs 8–9 ). AOIII with one pair of sensilla partly covered by integument, with common opening and without guard sensilla ( Fig. 11 ). Labral chaetae in three rows, proximal to distal 5-5-4 chaetae; middle three chaetae of basal row and median chaeta of middle row shorter than other chaetae; outer chaetae of distal row thickened, spike-like, on very small papillae ( Fig. 7 ). Head ventral chaetotaxy as in Fig. 6 : with 4+4 basomedian, 5+5 basolateral and 2+2 oral chaetae and with one pair of oval organs in the postlabial region. Maxillary outer lobe simple with three sublobal hairs. Labial palpus with six usual papillae (А–E, H), built as drawn for Sminthurus nigromaculatus Tullberg by Fjellberg (1999: Figs 86–87), except that only six proximal chaetae occur (proximal chaeta on papilla D missing), guard chaetae e7 missing. Head of maxilla not clearly visible, but maxillary lamellae extending past teeth of maxillary head. Eight ocelli and two chaetae in each eyepatches, ocelli C, D and G smaller ( Fig. 3 ).

Abdomen. Trichobothrium A, B, C and D present ( Figs 12 , 22 ). Large abdomen covered with macro-, meso- and microchaetae arranged as in Fig. 12 . Macro- and mesochaetae warty as shown in Figs 5 and 12 . Neosminthuroid chaetae missing. Abd. V included in the small abdomen, chaetotaxy as in Fig. 22 . Chaetotaxy of abd. VI as in Figs 21–23 , circumanal chaetae not winged, anal appendage thickened chaeta-like, slightly bent at distal part. Lateral valvae with one additional aai chaeta in both sex (marked as aai’ in Figs 21–22 ). In male mpi1 and mpi2 present, only mps3 missing. Ams3 (oval organ) very small ( Fig. 22 ).

Legs. Subcoxal process on legs II and III present. Subcoxae 1 I–III with 0,1,1 chaetae respectively and without detectable pseudopore, subcoxae 2 I–III with 0,1,2 chaetae respectively, coxae I–III with 1,3,4 chaetae respectively. Coxae II–III with one oval organ and one coxal microsensilla (microsensilé coxale in Nayrolles 1990). Trochanters I–III with 2 oval organs and with 5,6,6 chaetae respectively ( Figs 13–14 ). Femora I–III with one oval organ, one cup organ and 17,18,19 chaetae respectively. Tita I–III with five oval organs and with chaetotaxy as in Fig. 13 , almost identical with that given by Nayrolles (1988) for Sminthurus viridis (Linnaeus) except the presence of an additional chaeta on legs II (marked in Fig. 13 ) and III (on leg I present in both species). Each tita with three clavate tenent hairs, spatulate part hyalinous. Claw with one inner and one external tooth, with simple pseudonychia, without tunica, with one tooth on inner crest ( Figs 15–18 ). All empodia with one tooth and filament as long (in emp. III) or longer than claw ( Figs 1 5–16 ).

Ventral tube with 1+1 lateral and 1+1 anterodistal chaetae ( Fig. 20 ). Sacs retracted and vesicles not visible. Retinaculum with 3+3 teeth and four chaetae ( Fig. 19 ).

Furca. Manubrium with 8+8 posterior and 1+1 anterior chaetae in female and 7+7 posterior and 1+1 anterior chaetae in male ( Figs 26–27 ). Dens anteriorly with chaetae arranged as 3,3,3,2,2,1,1 ( Fig. 24 ), posteriorly with 8 chaetae in row E, 12 in row P and 9 in row J ( Fig. 25 ). Mucro with chaeta and with smooth edges as in Fig. 25 . Ratio: length of dens/mucro = 2.95 in female, 2.9 in male.

Discussion. The three spatulate chaetae on all tita separates the new species from Janusius daisetsuzanus ( Uchida, 1957) , Janusius sensibilis ( Börner, 1909) and Janusius sylvestris ( Banks, 1899) which have 5–6 spatulate chaetae on tita I–III. Apart from this character, J. geumgangensis sp. nov. differs from J. sylvestris also in appendices annales (smooth in geumgangensis sp. nov., with few to numerous fringes and short apical teeth in sylvestris ), and in the anterior chaetotaxy of dens (3,3,3,2,2,1,1 in geumgangensis sp. nov. and 3+1,3,3,2,2,1,1 in sylvestris ). J. geumgangensis sp. nov. differs from J. daisetsuzanus also in colouration (four wedge-shaped darker bands converging from the side to the postero-dorsal part of the great abdomen in daisetsuzanus , one pair brownish lateral spot in J. geumgangensis sp. nov.). Janusius sensibilis has no mucronal chaeta which is present in the new species. J. geumgangensis sp. nov. differs from the other Korean species, J. annulatus ( Kang & Lee, 2005) comb. nov. in the number of chaetae on retinaculum (2 in annulatus , 4 in geumgangensis sp. nov.) and in having mucronal chaeta (missing in annulatus ).

Figures

FIGURES 1 – 2. Janusius geumgangensis sp. nov.: 1, habitus, dorsal view (female); 2, habitus, lateral view (female) (without scale).

FIGURES 3 – 7. Janusius geumgangensis sp. nov.: 3, ocelli and frontal area (male, lateral view); 4, cephalic chaetotaxy (female, frontal view); 5, ornamentation of chaeta C 1 from head (female); 6, ventral cephalic chaetotaxy (female); 7, labrum (female, frontal view).

FIGURES 8 – 12. Janusius geumgangensis sp. nov.: 8, antennal segments II – IV (female); 9, distal subsegment of ant. IV (female); 10, tip of ant. IV (female); 11, AOIII (female, sensilla—under the integument—drawn in dashed lines); 12, chaetotaxy of great abdomen (male, detail: shape and ornamentation of chaeta a 1).

FIGURES 13 – 20. Janusius geumgangensis sp. nov. (female): 13, chaetotaxy of leg II (asterisk marks chaeta missing in Sminthurus viridis (Linnaeus )); 14, leg III basal part; 15, claw and empodium of leg II; 16, claw and empodium of leg III; 17, claw II seen from distal; 18, claw III seen from distal; 19, retinaculum; 20, ventral tube (lateral view).

FIGURES 21 – 27. Janusius geumgangensis sp. nov.: 21, abd. V – VI (female, caudal view); 22, abd. V – VI (male, lateral view), 23, abd. VI (male, dorsal view); 24, dens (female, posterior view); 25, dens and mucro (female, anterior view, arrow indicates mucronal chaeta); 26, manubrium (male, posterior view); 27, manubrium (female, posterior view).