Acanthacorydalis asiatica ( Wood-Mason, 1884 )

Bolotov, Ivan N., Bespalaya, Yulia V., Gofarov, Mikhail Yu., Spitsin, Vitaly M. & Tumpeesuwan, Sakboworn, 2014, First record of rare dobsonfly species Acanthacorydalis asiatica (Wood-Mason, 1884) (Megaloptera: Corydalidae: Corydalinae) in Myanmar, Zootaxa 3841 (3), pp. 446-450 : 446-449

Acanthacorydalis asiatica ( Wood-Mason, 1884)

( Figs 1–7 )

Corydalis asiatica Wood-Mason, 1884: 110 . Type locality: “Naga Hills, N.E. frontier of India ”.

Acanthacorydalis asiatica ( Wood-Mason, 1884) : Glorioso 1981: 282; Liu et al. 2005: 374; Yang & Liu 2010: 99.

Material examined. 3 females, Myanmar, Kachin State, Nam Ru River valley ( Mali Hka River Basin), near Wasandum village, 860 m alt., 27°29”41.7’ N, 97°11”23.5’ E, 18th March 2014, mountain rainforest with bamboo patches in the river valley, at light, Bolotov, Gofarov, Spitsin & Vikhrev leg. The specimens are deposited in the Biological Museum of the Institute of Ecological Problems of the North, the Ural Branch of the Russian Academy of Sciences, Arkhangelsk, Russia ( INEP).

Diagnosis. Head dark yellow with distinct black marks on the clypeus, in ocellar triangle and at base of antennae; a pair of almost triangular black spots laterally on vertex; narrow black band or few irregular black spots along posterior margin of the head. Pronotum dark yellow with a large round black spot at each corner, between these spots a notable arrowhead-like yellow spot.

Description of female. Body length 48–58 mm; forewing length 67–71 mm, hindwing length 60–61 mm.

Head large, subquadrate and flattened, with two prominent postocular spines, and with pair of spines on the vertex ( Fig. 1 ). Ground colour of the head dark yellow, with distinct black marks: one spot along clypeus, one spot in ocellar triangle, pair of spots around base of antennae, pair of almost triangular spots laterally on vertex, these spots connected with narrow black band (or few irregular black spots) along posterior margin of the head; spines black ( Fig. 2 ). Ventral surface of head dark yellow, with pair of lateral brownish black spots (near spines) and three brownish black spots along posterior margin. Compound eyes brown, ocelli dark yellow. Antennae black, filiform. Mouthparts blackish brown, bearing short yellowish and black setae; labrum yellow with black edging and black central spot or black with small yellow central spot. Galea yellow. Mandibles black; as long as the head; with one large inner basal tooth, one small inner median tooth (sometimes reduced to very small convexity) and one large inner apical tooth ( Fig. 3 ).

Prothorax 1.2–1.4X longer than wide at midlength, without setae; setae on meso- and metathorax long, light brownish. Pronotum dark yellow with one large roundish black spot in each corner, between spots, a distinct arrowheadlike yellow spot. Prosternum dark yellow, with anterior margin and posterior margin black, and with black spot near posterior margin. Mesonotum black; metanotum dark yellow with two large black spots. Meso- and metasternum blackish brown, with dark yellow areas near coxae, with long pale brown setae. Legs brownish black; inner surfaces of fore coxae, trochanters and bases of femora dark yellow; tarsal claws black; coxae, trochanters and femora with long golden setae, tibiae and tarsus with short black setae. Fore tibiae slightly S-curved. Forewings pale brown, darkened on posterior half; a few indistinct elongated black spots between main veins (spots “resembling dried splashes of muddy water,” Wood-Mason (1884)); veins brownish black, with black marks bordering crossveins; Rs 8–10-branched, usually MA bifurcate distally; 4–7 crossveins between R and Rs; MP1+2 2-branched; MP3+4 2-branched; CuA 4–5-branched; 1A 2-branched. Number of costal crossveins 33–38. Hindwings pale brown, sometimes with few black spots between R and Rs.

Abdomen dark yellow, with dark yellowish setae and black markings (each of 2nd–4th tergites with broad black band; each of 5th–9th tergites with three round black spots). Female tenth tergum sagitally divided by anus, and with free semicircular ventral portion; gonocoxite valvate and membranous, with apical portion subquadrate; tip of gonostylus digitiform ( Figs 4–5 ).

Remarks. Wood-Mason (1884) in his protologue noted that abdomen is brown, without brown or black marks. It is most likely, that abdomen of the type specimens became monochromatic brown due to poor drying. Similarly, he described the head and thorax coloration of type specimens as brown, but he assumed that live insects may have a green colour ( Wood-Mason 1884). Actually, live individuals have dark yellow body colour.

Habitat. Mountain oligotrophic zone of the Nam Ru River, Mali Hka River Basin (tributary of the Irrawaddy River) ( Fig. 6 ).

Distribution. Northeastern India (Assam State), northern Myanmar (Putao District, Kachin State) and southwestern China (Yunnan Province) ( Fig. 7 ).

Figures

FIGURE 6. Habitat of Acanthacorydalis asiatica in upstream of Nam Ru River, Kachin State, northern Myanmar. (Photo: Ilya V. Vikhrev).

FIGURE 7. Map with known localities of Acanthacorydalis asiatica. The red boundary represents the area of the type locality, the former Naga Hills District of British India (Wood-Mason 1884); the red circle represents our record from Kachin State, northern Myanmar; the blue circles represent records from Yunnan Province, China (Yang & Liu 2010). The digital elevation model and other layers of the map were added from Esri Data & Maps 10 dataset (Map: Mikhail Yu. Gofarov).

FIGURES 1 – 5. Female specimens of Acanthacorydalis asiatica from Nam Ru River valley, Kachin State, Northern Myanmar. Fig. 1. General view of a specimen; Fig. 2. Individual variability of marking patterns on head and pronotum; Fig. 3. Individual variability of left mandibles; Fig. 4. Apex of abdomen (lateral view); Fig. 5. Apex of abdomen (dorsal view). (Photos: Vitaly M. Spitsin).