Habaek koreanus, Murányi & Hwang, 2023

Murányi, Dávid & Hwang, Jeong Mi, 2023, A new genus and species of Perlodinae (Plecoptera: Perlodidae) from Korea, Zootaxa 5249 (1), pp. 138-150 : 140-146

Habaek koreanus sp. n.

( Figs. 1–22 )

Diagnosis: As for the genus.

Type material. Holotype male ( EMKU): SOUTH KOREA, Gangwon-do , Inje-gun , Girin-myeon , Bangdongri, Bangtaesan Natural Recreation Forest, 37°54′29.57″ N 128°24′25.14″ E, alt. 690 m, 11.V.–21.VI.2019, Malaise trap, leg. Daseul Ham, Sunghwan Park. Paratypes: same data as holotype: 1 female ( EMKU); Gangwon-do , Pyeongchang-gun , Jinbu-myeon, Odaesan, 37°47′5.67″ N, 128°34′16.97″ E, alt. 830 m, 1.VI.–14.VII.2019: 1 male ( NIBR, NIBRIN0000886471 ); Gangwon-do , Pyeongchang-gun , Jinbu-myeon , Bukdae Mireukam Temple, Odaesan, 37°48′12.82″ N, 128°34′03.02″ E, alt. 1296 m, 1.V.–29.V.2020, Malaise trap, leg. Jeong Mi Hwang, Ji Hyoun Kang, Daseul Ham, Sunghwan Park: 2 males, 2 females ( EMKU); same locality, 23.VI.–28.VII.2020, Malaise trap, leg. Jeong Mi Hwang, Ji Hyoun Kang, Daseul Ham, Sunghwan Park: 12 males, 9 females ( EMKU), 1 male, 1 female ( EKCU); Gangwon-do , Pyeongchang-gun , Jinbu-myeon, Odaesan, 37°47′34.58″ N, 128°33′37.97″ E, alt. 929 m, 29.V.–23.VI.2020, Malaise trap, leg. Jeong Mi Hwang, Ji Hyoun Kang, Daseul Ham, Sunghwan Park: 2 females ( EMKU); Gangwon-do , Pyeongchang-gun , Jinbu-myeon, Odaesan, 37°47′35.47″ N, 128°33′43.19″ E, alt. 941 m, 30.V.–23.VI.2020, Malaise trap, leg. Jeong Mi Hwang, Ji Hyoun Kang, Daseul Ham, Sunghwan Park: 1 male ( EMKU), 1 male, 1 female ( EKCU); Gangwon-do , Pyeongchang-gun , Jinbu-myeon, Odaesan, 37°45′19.09″ N, 128°34′22.24″ E, alt. 822 m, 29.V.–23.VI.2020, Malaise trap, leg. Jeong Mi Hwang, Ji Hyoun Kang, Daseul Ham, Sunghwan Park: 1 male ( EMKU); Gangwon-do , Pyeongchang-gun , Jinbu-myeon, Odaesan, 37°47′4.20″ N, 128°33′42.31″ E, alt. 822 m, 29.V.–23.VI.2020, Malaise trap, leg. Jeong Mi Hwang, Ji Hyoun Kang, Daseul Ham, Sunghwan Park: 1 male, 3 females ( EMKU); Gangwon-do , Gariwangsan Natural Recreation Forest in Hoedong-ri , Jeongseon-eup, Jeongseon-gun, 37°25′4.80″ N 128°31′27.51″ E, alt. 697m, 26.V.–20.VI.2020, leg. Daseul Ham, Sunghwan Park: 2 females ( EMKU).

Description: Medium sized Perlodinae , males brachypterous, females slightly brachypterous ( Figs. 17–18 ). Forewing length: holotype male 7.5 mm, male paratypes 6.5–7.5 mm, female paratypes 10.0–11.0 mm; body length: holotype male 14.0 mm, male paratypes 12.0– 12.5 mm, female paratypes 15.0– 15.5 mm. Sexual dimorphism regards size, terminalia and different wing length: female wings terminate above tip of abdomen while male wings do not cover terminal segments; shortened male wing has less crossveins but branching Radial vein. Setation generally short and dense. General colour dark brown, contrasting pale pattern on wings and appendages. Head and pronotum entirely dark brown; tentorial callosities and M-line hardly visible, occiput with well developed but not contrasting rugosities ( Fig. 11 ). Eyes and ocelli black and small, ocelli located far from each other, in a regular triangle.Antenna as long as the length of body, with more than 45 slightly clubbed antennomeres. Scape bicolored: base and inner edge dark brown, apex and outer edge light brown; pedicel and the next few antennomeres are light brown, gradually darkened towards dark brown two thirds of the antennae. Palpi brown, mouthparts mostly dark brown but glossa, paraglossa and apex of labrum contrastingly pale; vestigial submental gills present ( Fig. 4 ). Pronotum rectangular, about as wide as long, edges rounded; rugosities numerous and small. Meso- and metanotum dark brown with whitish membranes around the wing base. Forewing with contrasting pattern: costal area and anal field shiny dark brown with metallic tint, the rest of the remigium off-white; venation brown, darker in the costal area. Hindwing is less contrasting, mostly brown with dark brown costal area ( Figs. 2–3 ). Ventral surface of thorax contrasting: membranous areas white, while sclerotized plates brown to dark brown. Legs long and slender; tibiae distinctly longer than femora, and even more slender; claws symmetrical, arolium large. Femora dark brown with contrasting pale apical ring. Basal third of tibiae dark brown, then gradually lightened towards pale brown apical third. Tarsi light brown to brown but apical half of metatarsi dark brown.

Ventral sclerites of thorax ( Fig. 1 ): Prothorax: cervical sclerites large, with bud-like gill vestiges; rounded presternum fused with small basisternum,both with a longitudinal median ridge;precoxal bridge vestigial,eutrochantin well developed; furcasternum large and triangular, fused with basisternum, postcoxal bridge and medially ridged postfurcasternum; the furcasternal area similar to the mesothoracic furcasternum–furcasternal arm–furcasternal pit complex. Mesothorax: anterior thoracal bud-like gill vestiges present; spinasternum vestigial, presternum large and triangular, fused with the small, stripe-like basisternum; trochantin stripe-like; furcasternum large and triangular, fused with basisternum; furcal pit (furcasternal arm) connecting anteriorly to arm of mesosternal ridge that continued in a long stem (furcasternal pit); areas between furcal pit and stem sclerotized but hardly delimited. Metathorax: anterior thoracal bud-like gill vestiges present; spinasternum vestigial, presternum large and triangular, fused with the small, stripe-like basisternum; trochantin stripe-like; furcasternum large and quadrangular, fused with basisternum; furcal pit connecting to lateral margin of furcasternum; sternum I fused with furcasternum.

Wing venation ( Figs. 2–3, 5–6 ): Forewing: Costal field enlarged, with many irregular, often forked or interrupted crossveins between Costa and irregular Subcosta, humeral crossvein not clearly distinguishable. Subcosta joins the unbranched Radial vein before single radiomedial crossvein in the female, well after the branching of Radial vien in the male; there are one or two crossveins between Subcosta and Radial vein, further two between Costa and Radial vein, stigma is lacking. Medial vein originates independently from Radial vein but its base is obscure, the two veins are distinctly separated well before arculus; Medial vein branches into an irregular network shortly after arculus in the female, with several crossveins, and four longitudinal veins reaching wing margin. There are 3–5 mediocubital crossveins besides arculus. Cu1 and Cu2 branching before arculus, cubital cell quadrangular, there are 8–9 cubital crossveins in the female, 3–4 in the male; Cu1 ends about the position of Radial vein ending, last 2–3 crossveins end directly in wing margin, Cu2 ends about the position of Subcosta ending. Cubital vein and A1 basally fused, branches at the anal crossvein, cubitoanal crossvein distinct in the female but lacking in the male; A1 strongly curved after the crossveins, ends about half of wing length. There are three further anal veins besides A1; A2 and A3 can be connected with a crossvein, A4 is very short. Hindwing: Enlarged costal field, Costa, Subcosta and Radial vein network is generally similar to forewing, but humeral crossvein can be identified more distinctly. Origin of Medial vein separated from Radial vein, similarly to forewing, but irregular network of its branching is with less crossveins. There are two mediocubital crossveins besides arculus. Cu1 and Cu2 branching before arculus, cubital cell quadrangular but short, there are 5–6 cubital crossveins. Cubitoanal crossvein short and connected to a basal anal cell, there is an additional crossvein between Cu2 and A1 well after half wing length. Anal field very large and as long as the remigium, the fold of the wing extending between the parallel Cu2 and A1. Additional A veins are 7–8, branching irregularly, the last Anal vein gives irregular crossveins towards wing margin.

Male abdomen ( Figs. 7–8 , 19–20 ): Segments I–II are fully divided into terga and sterna by pleura, segment III with shallow posterior notch of pleura, rest of the segments are entire. Terga I–III with wide, lightly sclerotized medial field, tergum IV with small medial field, terga V–IX entirely sclerotized and unmodified, dark brown; terga I–IX with entire antecosta, lack sensilla basiconica. Tergum X full divided into hemiterga; mostly dark brown, apical portions lighter, lack sensilla basiconica. Hemiterga triangular with rounded apex, the apical halves are converging in dorsal view, and elevated in lateral view; the wide basal anchor of epiproct divides hemiterga in the basal third by more than half of segment width, apices of hemiterga divided by a gap as wide as one fifth of the segment width. Sterna I–VIII brown, gradually darkening towards the apical segments, lacks vesicle. Sternum IX forms a well developed, rounded subgenital plate, covering sternum X and most of paraproct; sternum X widely divided medially. Paraproct dark brown, triangular with narrowed apical half, ending in a blunt apex; eversible portion is lacking. Cercus as long as the length of body, with 22–24 cylindrical segments, apical ones are rather elongated; basal 4–5 cercomeres yellowish, the rest is gradually darkened towards dark brown apical half of the cercus, but each cercomere with pale apical ring.

Epiproct ( Figs. 7–8 , 12–14 , 19–20 ): Basal anchor large and wide, connected to large, posteriorly directed lateral arms with raised tip, stretching basal membranes.The lever arm long and curved, rather wide in dorsal view, separated from the complex epiproct tip. The epiproct tip is shaped like an elongated 8 in dorsal, straight stripe-like in caudal, and half moon shaped in lateral view; most of the surface is lightly coloured but with a wide, lateral dark stripe and a dark dorsal ridge; the apex is arrow-shaped, tip slightly down curved in lateral view, and basally connected to rounded membranous portion. Paragenital plate large and bears ventral projection; stripe-like and slightly curved in dorsal view, dorsal portion darker in lateral view and with down curved apical portion, ventral projection has caudal edge perpendicular to the dorsal portion. Lateral stylet small, not fused and hidden in the cowl in resting condition of the epiproct; curved and stripe-like, apex with a curved, acute tooth. The cowl is densely covered by setae on most of its surface, with the exception of the dorsal surface basally to lateral stylets; bears a distinct, wide field of dense, tiny golden spikes between the stretched lateral stylets, seen only in fully everted position. In everted condition of the epiproct, the lateral arms of basal anchor raised dorsad, as well the rather enlarged cowl and epiproct tip that is fully exposed. Paragenital plates only slightly change posture, holding tight the base of the cowl. The lateral stylets are turning outwards by the base of the epiproct tip, stretching the apex of the cowl into two small, apicolateral lobes, and exposing the field of golden spines in front of the epiproct tip. The everted cowl has no other lobes, its shape is blunt conical in lateral, and rectangular in caudal view.

Aedeagus ( Figs. 15–16 ): Shape and lobes of the fully everted aedeagus remained unknown, but surface armatures and certain lobes around the armatures were clearly seen after dissection. On the ventral surface, golden brown scales are forming a large T-shaped loop; the scales are irregular small plaques with raised flanges. Adjacent to the upper part of the T, a pair of small lobules present, while the lower stem of the T is connected to a larger lobe forming an upside down C, bearing a small patch of scales beneath the stem of the T. Both the paired lobules and the lower lobe bear minute colourless spicules, scarce spinules distributed also on the surface beneath lower lobe; the surface lateral and above to the T is rarely wrinkled. The dorsal surface is armed with three small patches of golden scales similar to the ventral surface but no spicules; the upper two, elongated patches are positioned on inverting lobes, while the third, rounded patch is positioned medially on a rounded lower lobe.

Female abdomen ( Figs. 9–10 ): Segments I–II are fully divided into terga and sterna by pleura, segment III with shallow posterior notch of pleura, rest of the segments are entire. Terga unmodified, uniformly brown but apical two segments are darker, all with entire antecosta. Sterna I–VII brown, gradually darkening towards the apical segments. Subgenital plate reduced to a very slightly protruded, widely rounded posterior margin of sternum VIII, slightly bulging in lateral view; sternum VIII dark brown, with an inconspicuous longitudinal pale stripe medially. Sterna IX–X unmodified, dark brown but sternum IX with a mediobasal paler area. Paraproct dark brown with paler tip, elongated and narrow triangular, ending in a blunt apex. Cercus nearly as long as the length of body, with 24 cylindrical segments, apical ones are rather elongated; basal 3–4 cercomeres yellowish, the rest is gradually darkened towards dark brown apical two thirds of the cercus, but each cercomeres with narrow, pale apical ring.

Egg: No fully matured eggs are available, but one of the females contains several dozens of nearly matured eggs. These are spherical, elongated oval with 0.3–0.4 mm length and 0.2–0.3 mm diameter. The chorion is golden light brown, apparently with dense punctuations of FCIs. No traces of collar or rims can be recognized.

Larva: unknown.

Affinities: As for the genus.

Ecology and distribution: The species was caught by Malaise traps during May, June and July. The traps were set at elevations ranging from 700 to 1300 m, along medium sized forest streams with fast flow and mixed rocky and sandy substrate ( Fig. 21 ). The known localities are located in the Thebaek ranges, in three counties of Gangwon province (Gangwon-do): Inje-gun, Pyeongchang-gun, Jeongseon-gun ( Fig. 22 ).

Etymology: The name koreanus refers to the Korean Peninsula where this remarkable stonefly was found. Used as a noun adjective, gender masculine.

Figures

FIGURES 1–6. Somatic characters of Habaek koreanus gen. n., sp. n.—1: ventral sclerites of the female thorax (P: prothoracic; Me: mesothoracic; M: metathoracic–Bs: basisternum; Cx: coxa; Etn: eutrochantin; Fs: furcasternum; Fsa: furcasternal arm or furcal pit; Fsp: furcasternal pit or stem of mesosternal ridge; Gv: gill vestige; Lcs: lateral cervical sclerite; Pfs: postfurcasternum; Pn: pronotum; Po: postcoxal bridge; Pr: precoxal bridge; Prs: presternum; Ss: spinasternum; St1: sternum 1; Tn: trochantin; Tr: trochanter); 2: female forewing; 3: female hindwing (A: anal vein; a: anal crossvein; arc: arculus; C: costa; Cu: cubital vein; cu-a: cubitoanal crossvein; h: humeral crossvein; M: medial vein; m-cu: mediocubital crossvein; R: radial vein; r-m: radiomedial crossvein; Sc: subcosta); 4: female head, ventral view (arrow indicates submental gill); 5: female forewing; 6: male forewing—scales 1 mm.

FIGURES 7–11. Terminalia, head and pronotum of Habaek koreanus gen. n., sp. n.—7: male terminalia, dorsal view; 8: same, lateral view; 9: female terminalia, ventral view; 10: ventral edge of female terminalia, lateral view; 11: head and pronotum, dorsal view (holotype)—scales 1 mm.

FIGURES 12–16. Male epiproct and aedeagus of Habaek koreanus gen. n., sp. n.—12: everted epiproct and terminal segment, lateral view; 13: same, caudal view; 14: same, dorsal view (Ba: basal anchor; Co: cowl; Et: epiproct tip; Ht10: hemitergum 10; La: lateral arm; Le: lever arm; Ls: lateral stylet; Pg: paragenital plate; Pp: paraproct); 15: aedeagus, ventral surface; 16: same, dorsal surface—scale 1 mm.

FIGURES 17–20. Habitus and male terminalia of Habaek koreanus gen. n., sp. n.—17: male habitus, dorsal view; 18: female partial habitus, dorsal view; 19: male terminalia with partly everted epiproct, dorsal view; 20: same, ventral view—scales 1 mm.

FIGURE 21–22. Habitat and distribution of Habaek koreanus gen. n., sp. n.—21: type locality habitat of Habaek koreanus gen. n., sp. n.: South Korea, Bangtaesan Natural Recreation Forest (photograph by Sunghwan Park); 22: distribution of Habaek koreanus gen. n., sp. n. in the Korean Peninsula (type locality signed with a ring).