Heterangaeus koreanus, Podenas, Sigitas, Podeniene, Virginija & Byun, Hye-Woo, 2015

Podenas, Sigitas, Podeniene, Virginija & Byun, Hye-Woo, 2015, Heterangaeus Alexander, 1925 crane flies (Diptera: Pediciidae) of Korea, Zootaxa 4006 (3), pp. 506-520 : 511-518

Heterangaeus koreanus n. sp.

Diagnosis. Medium-size yellowish species. Antenna very short, if bent backwards, reaching pronotum at most; dark brown at base, turning whitish at apex. Distinguished from other species in genus by shape of wing, details of venation, wing pattern, and structure of male terminalia. Wing ( Fig. 5 ) paddle-shaped, with clearly sinuous posterior margin, distinct emarginations not only at tips of both anal veins, but also at posterior margin of second anal cell. Anal angle large, second anal cell wide. Vein Sc2 well before base of Rs; cell m1 with short stem; basal deflection of CuA1 distinctly beyond branching point of M. Wing with distinct and abundant dark pattern. Pigmented areas surrounded by darker margins. The most distinctive are two cross-bands, connected along vein Rs, thus forming “8”-shaped light “window” in the middle; Costal cell mostly clear, basally with weak brownish tinge. Male gonostylus ( Fig. 6 ) club-shaped, with single strong subapical spine; interbase ( Fig. 9 ) horn-shaped; ninth tergite ( Fig. 7 ) with smooth posterior margin and narrow lateral incisions; ninth sternite ( Fig. 10 ) with “U“-shaped incision in the middle. Ovipositor ( Fig. 11 ) with wide arched cercus and straight, comparatively narrow hypovalvae. Dorsal margin of hypovalvae bearing seven long bristles.

Description. Adult, male ( Figs. 5–10 ). Body length 8.4–8.9 mm; wing length 9.8–9.9 mm. Body yellowish brown. Head dark brown, somewhat lighter ventrally, covered with brownish gray pruinosity, vertex covered with sparse erect whitish setae. Rostrum black. Mouth parts brown. Antenna 0.65–0.87 mm long, if bent backwards, not reaching beyond pronotum. Scape cylindrical, elongate, black ventrally, brown dorsally, covered with sparse grayish pruinosity. Pedicel less than half the length of scape, getting slightly wider toward distal end, reddish brown with somewhat lighter distal end. Both basal segments bearing strong sparse brown setae. Flagellum 11- segmented, basal segments brownish yellow, middle segments yellow, distal segments whitish. Basal flagellomeres oval, remaining segments subglobular, distal flagellomeres elongate, nearly cylindrical. Verticils white and long, approximately three to four times as long as respective segments. Flagellomeres ventrally covered with very short white pubescence. Palpus very long, distinctly longer than antenna, blackish, length of distal segment distinctly exceeds that of preceding segment. Palpus covered with dark erect setae. Thorax generally brownish yellow. Pronotum brown dorsally, with yellowish lateral margins. Prescutum uniformly colored, reddish yellow in lighter specimens, light brown in darker specimens. Pseudosutural fovea yellowish. Prescutal stripes not expressed. Scutal lobes slightly darker than prescutum, especially frontally. Scutellum yellow to fulvous. Mediotergite frontally yellow, turning fulvous posteriorly in lighter specimens, in darker specimens brownish yellow. Pleuron generally yellow, area surrounding wing base and ventral part darkened. Darker specimens with rather distinct oblique dark line extending from head through katepisternum to coxae of middle and posterior legs. Katepisternum without setae. Wing ( Fig. 5 ) iridescent with heavy dark pattern. Dark spots surrounding all cross-veins, branching points and tips of all longitudinal veins. Pigmented areas surrounded by darker margins. The costal cell darkened just at wing base before humeral vein, beyond that it is light with just very tip darkened. Wing base darkened frontally to first anal vein. Separate spot surrounds Sc2. Cross-band starting at base of Rs and connected with spot surrounding additional crossvein in the middle of cell m. Another cross-band extends along cord. Both cross-bands connected along vein Rs, forming characteristic “8“-shaped figure. Another oblique band extends from tip of R3 through distal cross-veins and branching points and reaching basal deflection of CuA1. Shape of spots at distal wing end variable even in same specimen. Cell cu mostly darkened with some light spots in the dark background, but these spots also variable in different specimens. Large spot at tip of first anal vein is connected with dark area in cell cu and with dark spots at tips of CuA1 and CuA2. Large spot with light nucleus is at base of first anal cell. It is connected with large dark spot at tip of second anal vein. That spot covers whole distal part of second anal cell. Venation: vein Sc1 very long, reaching beyond branching point of R2+3 and R4. Vein Sc2 situated long distance before base of Rs. Base of Rs distinctly angulated and long-spurred in some specimens, in other spur is missing, or Rs base arched. Base of R2+3 angulated and short-spurred. Additional cross-veins in cells r1, r3, r4, m1 and m. Cell m1 with short stem, discal cell comparatively short, less than half as long as wide. Additional cross-vein in cell m approximately at same level as base of Rs. Basal deflection of CuA1 distinctly beyond branching point of M. Both anal veins strongly divergent. Posterior wing margin distinctly wavy, distinct emarginations not only at tips of both anal veins, but also at posterior margin of second anal cell. Anal angle comparatively big, second anal cell widest in the central part. Halter 1.33–1.45 mm long, stem whitish, knob yellowish. Legs: frontal coxa yellow, middle coxa brownish, posterior coxa yellowish with brownish infuscation. Trochanters yellow, ventral margin narrowly darkened. Femorae of all legs generally yellow, with whitish bases and distinctly darkened distal ends. Tibiae white with darkened apices. Basal tarsomere yellow with whitish base and narrowly darkened distal end. Second tarsomere light brown basally, turning dark brown distally. Remaining tarsomeres dark brown. Short, semi-erect setae, covering legs, same color as area on which they are distributed, yellow on femur, white on tibiae and dark brown on darkened apices of segments. Femur I: 4.75–5.30 mm long, II: 4.20–6.00 mm, III: 5.50–5.75 mm; tibiae I: 5.10– 6.00 mm, II: 4.90–5.50 mm, III: 5.40–6.30 mm; tarsus I: 7.20–7.60 mm, II: 5.60–6.20 mm, III: 5.80–6.20 mm long. Abdominal tergites yellowish brown. Basal tergite with whitish lateral margins. Posterior tergites dark brown. First abdominal sternite brownish with whitish lateral margins. Succeeding sternites generally brownish yellow, with brown posterior margin and fuzzy brownish lateral stripes. Posterior sternites dark brown. Abdomen covered with scarce semi-erect, whitish setae. Male terminalia ( Fig. 7 ) reddish brown. Ninth tergite with straight posterior margin, which is covered by pubescence, lateral margins of ninth tergite with narrow incisions. Gonocoxite with widened distal end covered in short black spines and separated from the rest of gonocoxite by somewhat narrower “neck“. One pair of gonostyli. Gonostylus ( Fig. 6 ) elongated, club-shaped with strong subapical black spine, margin on the opposite side covered with a few fine setae. Interbase ( Fig. 9 ) horn-shaped, slightly arched. Aedeagus ( Fig. 8 ) short and wide with darkened distal part. Ninth sternite with “U“-shaped incision.

Female ( Fig. 11 ). Body length 9.8–11.5 mm; wing length 11.4 mm. Body coloration generally similar to that of male, but more whitish, than yellowish. Antenna 0.93–1.85 mm long. Halter 1.40–1.65 mm long. Femur I: 5.3–5.6 mm long, II: 5.5–5.7 mm, III: 6.1–6.3 mm; tibiae I: 5.5–5.6 mm, II: 5.3–5.7 mm, III: 6.1–6.3 mm: tarsus I: 7.6 mm, II: 5.0– 6.2 mm, III: 5.8–6.9 mm long. Posterior end of abdomen less darkened than in male. Ovipositor ( Fig. 11 ) grayish brown. Cercus wide, tip raised upwards. Hypovalvae straight and comparatively narrow, dorsal margin bearing seven pairs of strong setae. Distal-most pair separated from the rest, six frontal pairs follow each other in comb-like fashion, frontal pair the shortest, caudal the longest.

Larva ( Figs. 12–18 ). Last instar larvae. Body length 13.0– 14.9 mm; width 1.7–2.4 mm. Larvae are hemicephalic, metapneunistic. Body covered with long dark brown setae, which gives body brown-greenish color. Tergum and sternum are covered with longer setae forming longitudinal lines. Line of longer setae on tergum is interrupted by area of very short pubescence on the seventh abdominal segment ( Fig. 12 ). Line of longer setae on sternum is continuous and reach anal field ( Fig. 13 ). The first thoracic segment and abdominal segments 3 – 7 are longer than wider. Two other thoracic and first two abdominal segments are longer than wider. Abdominal segments 4 – 7 with well developed ventral creeping welts, laterally elevated into humps. Creeping welts on 5 – 7 segments are slightly longer than on 4th segment and their length increases gradually towards posterior end. Apical part of each welt bears short, dark brown spinulae.

Head capsule. Length 1.14–1.22 mm, width 0.50–0.53 mm. Well-sclerotized, massive, dorsally depressed, narrow and elongate in shape, partially retracted within thorax. Lateral margins of head capsule parallel, posterior parts of genae are heavily sclerotised. Dorsal sutures short, arched and directed outward. Frontoclypeal suture straight with side parts raised up. Mandible with long setae at the base. Eight sensory pits located around the setae and one pit near the middle line ( Fig. 14 ). A sensory pit is near the middle of frons. One long and one medium length setae and three sensory pits are at the base of maxilla ( Fig. 15 ). One long seta is at the base of maxilla near hypostoma. Length of groove, formed by frontal suture, is 2/ 3x the head capsule. Posterior part of frons pointed. Clypeus wide and trapezoidal, with rounded margins. Labrum saddle-shaped with several sensory structures: one seta of medium length and two sensory papillae near the anterior margin, four short sensory papillae and a tubercle with sensory pegs on anteriolateral part, a long seta and four short papillae are in the middle ( Fig. 16 ). Epipharynx covered with short dense bristles. Antenna short, reaching apical part of clypeus ( Fig. 14 ). Basal segment cylindrical, with sensory pit near the base, twice as long as wide, with two very long but equal in length apical FIGURES 12–18 . (Continued) papillae (1.3x the length of basal segment itself) and four short sensory papillae on the apex of basal segment of antenna ( Fig. 14 ). Mandible large, heavily sclerotised and sickle-shaped. Apical tooth is the largest ( Fig. 17 ). First and second dorsal teeth are small, similar in size, triangular, with blunt apex. Third tooth is more than twice as long as other dorsal teeth, horn-shaped. First and second ventral teeth small and blunt. Third and fourth teeth large, triangular. Fourth tooth curved and sharply pointed. Two long setae at base of mandible. A sensory pit located on dorsal surface of mandible, near the dorsal teeth. Maxillae well developed, consists of outer lobe (palpiger) and inner lobe (galea) ( Fig. 15 ). Palpiger cylindrical, more prominent, with large sclerite at the base. Apical part surrounded by sclerotised ring. Palpus button-shaped with few sensory structures (exact number was difficult to establish). A sensory pit is on the outer margin and another sensory pit is on the inner margin of apical part of palpiger. Galea finger-shaped with large sclerite at the base. Apical part of galea sclerotised with two long setae and one papilla. Cardo arched, well developed with two very long setae and a sensory pit. Hypostoma heavily sclerotised, divided into two plates each of which bears four sharp teeth ( Fig. 15 ). The outermost tooth significantly shorter; the other teeth are similar. Plates connected with well developed push-button connection. Prementum as a flattened plate with protruding lateral lobes and set apically with short teeth ( Fig. 18 ).

Spiracular disc. Spiracular disc bears two conical elongated ventral lobes. Each of them more than three times as long as its width at base, pointed apically, with three long setae at the apex ( Fig. 12 ). Spiracles are very small, elongated in shape. The distance between spiracles almost equal to the width of a spiracle. Spiracular disc (except small area around the spiracles) entirely covered with setae.

Anal field. Anus surrounded by four very short, segmented, white and fleshy anal papillae, which are fingershaped and equal in size, one-third the length of spiracular lobes.

Period of activity. Adults are flying from late April through end of August.

Habitat ( Fig. 19 ). Wet muddy mountain slopes covered by deciduous trees well above river level. Larvae were collected from mud accumulated on stones under leaf litter or mosses.

Distribution. South Korea.

Examined material. Holotype, male (pinned). South Korea, Jeollanam-do province, Gurve, Toji-myeon, Naedong-ri, Piakol valley, N35.26586, E127.58090, altitude 448 m, 2012.04.27, collected by S. Podenas.

Paratypes. 1♂ (pinned), South Korea, Jeollabuk-do, Namwon, Sannae-myeon, Deokdong-ri, N35.33629, E127.53230, altitude 727 m, 2013.05.0 7, collected by S. Podenas; 1♂, 2♀♀, (1♂, 1♀ pinned; 1♀ body in ethanol, wings slide mounted, ovipositor in microvial on pin), South Korea, Jeollanam-do province, Gurve, Toji-myeon, Naedong-ri, Piakol valley, N35.26580, E127.58128, altitude 378 m, 2013.05.10, collected by S. Podenas; 3♂♂, 1♀, (2♂♂, 1♀ pinned, 1♂ in ethanol), South Korea, Gyeonggi-do, Gapyeong-gun, Buk-myeon, Hwaak-ri, N37.99363, E127.52102, altitude 810 m, 2014.08.20, collected by S. Podenas.

Larvae. 4 presumable last instar larvae from S. Korea, Gyeongsangnam-do, Hamyang, Macheon-myeon, Samjeong-ri, N35.35880, E127.63672, altitude 692 m, 2013.05.11, collected by V. Podeniene; 7 presumable last instar larvae from South Korea, Jeollanam-do province, Gurve, Toji-myeon, Naedong-ri, Piakol valley, N35.26580, E127.58128, altitude 378 m, 2013.05.12, collected by V. Podeniene.

Etymology. Species is named for the country of its discovery, Korea.

Discussion. H. koreanus n. sp. is related to H. gloriosus gloriosus ( Alexander, 1924) . Main differences are observed in wing pattern and wing venation ( Figs. 1 , 5 ), as well as in male and female genitalia ( Figs. 2–4 , 6, 9 ). Wing cell c beyond humeral vein is clear in H. koreanus n. sp., when that of H. gloriosus gloriosus has dark spot above the origin of Rs. Vein Sc 2 in H. koreanus n. sp. is well before base of Rs, thus dark spot, surrounding it, is separate from spot, surrounding base of Rs. Because Sc 2 in H. gloriosus gloriosus is close to Rs base, thus it is surrounded by same dark spot, which surrounds base of Rs. H. koreanus n. sp. has extra cross-vein in cell r1, which is missing in H. gloriosus gloriosus . The most distinct feature of H. koreanus n. sp. wing is distinctly darkened area along whole Rs. It makes characteristic “8“-shaped figure in central part of wing. Central part of Rs not surrounded by dark area in H. gloriosus gloriosus , thus central transparent area of wing is not separated and more resembles transverse light band. Pigmentation of cell cu in both species is variable, but that of H. koreanus n. sp. is mostly darkened with separate small light spots, when that of H. gloriosus gloriosus is mostly light with 6–7 dark spots. Posterior margin of wing distinctly emarginate in H. koreanus n. sp., deep emarginations present not only at apices of both anal veins, but also at posterior margin of cell a2. Posterior wing margin of H. gloriosus gloriosus only shallowly emarginated. Gonostylus of male genitalia is wider, and subapical spine longer in H. koreanus n. sp., than in H. gloriosus gloriosus . Gonocoxite of H. koreanus n. sp. has distinctly narrowed “neck“, which is not visible in paratype of H. gloriosus gloriosus . Distal part of interbase of H. koreanus n. sp. is straight and narrow, when that of H. gloriosus gloriosus is wider and slightly arched. Female of H. gloriosus gloriosus is undescribed, but we compared H. koreanus n. sp. females with a female from Japan. Ovipositor of Korean female has comparatively shorter and wider cercus and narrower hypovalvae. Dorsal margin of hypovalvae of Korean females has seven pairs of strong setae, Japanese female just six pairs. Caudal pair of setae, separated from the frontal six pairs by wide gap, is totally missing in Japanese specimen.

Overall appearance of larva of H. koreanus n. sp. is the same as H. mongolicus . Length and color of setae covering body are different in these two species. H. mongolicus is covered with short white setae, when body of H. koreanus n. sp. is covered with long and dark brown setae. Both species have long setae on tergum forming longitudinal line which is interrupted by shorter setae on last abdominal segment and this once again confirm, that this character could be one of the distinguishing features for larvae of this genus. Line of longer setae on sternum is visible just in H. koreanus n. sp. Both species have creeping welts on 7–10 abdominal segments, which look like humps. Differences were noticed in coloration of spinulae covering humps: in H. mongolicus they are light brown in H. koreanus n. sp. dark brown. Number and shape of anal papillae are the same in both species. Shape and length of spiracular lobes of H. mongolicus and H. koreanus n. sp. is very similar. It was noticed that H. koreanus n. sp. has three setae at the apex of spiracular lobe, but it is hard to say if these setae really absent in H. mongolicus or they are just broken on the specimens examined.

The general appearance of head capsule of H. mongolicus and H. koreanus n. sp. is very similar. Differences were noticed in number and arrangement of sensory structures on labrum and frons. Antennae of H. mongolicus and H. koreanus n. sp. are similar, but H. koreanus n. sp. has four papillae on the apex, when H. mongolicus has only three. Mandibles of both Heterangaeus species are similar in shape. Differences were noticed just in shape of fourth ventral teeth. The most significant differences were noticed in hypostoma. Each part of hypostoma of H. koreanus n. sp. bears four teeth, when H. mongolicus bears just three. Two parts of hypostoma are held together with push-button connection (which connects two plates of hypostoma) in H. koreanus n. sp., when in H. mongolicus push-button connection is not well developed. Larvae of both species of Heterangaeus develop in organic-rich mud; H. koreanus n. sp. was collected from mud accumulated on the stones and H. mongolicus from mud in marsh.

H. koreanus n. sp. is the first species of the family Pediciidae listed from the territory of South Korea.

Figures

FIGURE 19. Habitat of Heterangaeus koreanus n. sp. (Piakol valley).

FIGURES 5 – 11. Heterangaeus koreanus n. sp., paratypes. 5, wing; 6, gonostylus; 7, male genitalia, dorsal view; 8, aedeagus; 9, interbase; 10, ninth sternite; 11, ovipositor, lateral view.

FIGURES 12 – 18. Heterangaeus koreanus n. sp., larva. 12, tenth and eleventh body segments, dorsal view; 13, tenth and eleventh body segments, ventral view; 14, labrum, clypeus, left antenna and uppermost part of frons, dorsal view; 15, left maxilla and hypostoma, ventral view; 16, labrum and clypeus, dorsal view; 17, left mandible, dorsal view; 18, prementum, ventral view.

FIGURES 1 – 4. Heterangaeus gloriosus gloriosus. 1, wing of female from Paiktusan, N. Korea; 2 – 4, male genitalia, paratype from Saghalien Island: 2, gonostylus; 3, gonocoxite with gonostylus and interbase; 4, interbase; 5, ninth sternite of male from Japan.