Helicopsyche lamnata, Johanson & Pham, 2012

Johanson, Kjell A. & Pham, Hong-Thai, 2012, Three new species of Helicopsyche (Trichoptera, Helicopsychidae) from northern Vietnam, with a key to Helicopsyche species of Vietnam, European Journal of Taxonomy 6, pp. 1-10 : 7-9

Helicopsyche lamnata sp. nov.

Fig. 3

Diagnosis

Helicopsyche lamnata sp. nov. is most similar to H. vongsombathi Johanson & Malm, 2007 , from which it is easily distinguished by the presence of a central posterior process of segment IX and the distal part of the gonopods are more strongly produced posteriorly. The species also resembles H. meander sp. nov., particularly by the nearly club-shaped apex of tergum X in lateral view, but in H. lamnata sp. nov. the VIth sternal process is much longer and the gonopods are less sharply sigmoid.

Etymology

Lamnata, plate-like in Latin, refers to the process on the posterior margin of sternite IX.

Material examined

Holotype ♂

VIETNAM: Vinh Phuc Prov, Me Linh District , stream near Ngoc Thanh Village , Melinh Station for Biodiversity , 21°23'28.2"N, 105°42'46.7"E, 233 m, Malaise trap 4-12 Apr. 2011, loc#VN001, leg. K.A. Johanson, P.H. Thai & T.T. Du ( NHRS, alcohol) [DNA voucher IP9].

Paratype Same data as holotype, except ( IEBR, alcohol).

Description

MAXILLARY PALPS. Two-segmented, all segments sub-equal in length. Pair of interantennal setal warts very large, spherical, elevated, densely covered by long setae. Each scapus slightly longer than individual segments of maxillary palps. Spur formula 1,2,4; each foreleg spur nearly as long as each first tarsomere.

LENGTH. Forewing 4.0 mm, hind wing 3.1 mm (N = 1).

MALE ABDOMEN AND GENITALIA. ( Fig. 3 ) Sternal process VI about two-fifths as long as sternum VI, straight, oriented posteroventrad; parallel-sided in lateral view ( Fig. 3A ); almost parallel-sided in ventral view ( Fig. 3B ). Segment IX slightly taller than long in lateral view ( Fig. 3C ); each anterior lobe of segment IX ( Fig. 3C ) smoothly narrowing anteriorly in lateral view, asymmetrical, oriented anterodorsad; anterodorsal margin almost straight; anteroventral margin concave ( Fig. 3C ); in dorsal view, inner margin forming narrowly ellipsoid cavity ( Fig. 3D ); large central posterior process located below basis of gonopods, sharply triangular in lateral view ( Fig. 3C ); in ventral view widely trapezoid, with slightly concave posterior margin. Lateral apodemes nearly horizontal ( Fig. 3C ), parallel-sided along their length, located at mid-height of segment IX, ending in sub-marginal line; tergal transverse apodemes absent; sternal transverse apodeme oriented in right angle to lateral apodeme, located along posterior margin of segment IX ( Fig. 3C ). Transverse plate absent. Tergum X, in lateral view, oriented posteroventrad ( Fig. 3C ), strongly tapering towards mid-length, with single, dorsolateral, stout seta at mid-length; distal half almost parallel-sided, apex slightly club-shaped, orienting posteroventrally ( Fig. 3C ); in dorsal view ( Fig. 3D ), deeply and narrowly divided into pair of parallel-sided and parallelrunning branches; each with 4 pairs equally long megasetae in apical group, and two pairs stout, posteradoriented spines ( Fig. 3C ). Superior appendages club-shaped ( Fig. 3C ), oriented posteroventrad. Primary branch of gonopods, in lateral view ( Fig. 3C ), with basal part oriented posterad before strongly bending posterodorsad, curving posterad after mid-length, apical part rounded in dorsal view; produced mesad into pointed plates above tergum X in dorsal view ( Fig. 3D ); slightly widening along their length; basal part of anterior margin smooth; dorsal and posterior margins undulating. Secondary branch of gonopods absent. Basomesal lobes long, slightly broadening before apex, each with pair of apical setae; straight in lateral view ( Fig. 3C ), diverging in ventral view ( Fig. 3E ). Basal plate, in lateral view ( Fig. 3C ), straight, strongly narrowing anteriorly towards mid-length, anterior half very slender, not produced beyond anteroventral margin of segment IX in lateral view ( Fig. 3C ); almost parallel-sided in ventral view ( Fig. 3E ), with rounded anterior apex. Phallic apparatus, lateral view, irregularly tube-shaped along its length ( Fig. 3F ), apex about as broad as base; nearly straight after mid-length; irregular in ventral view ( Fig. 3G ); widest after mid-length; endotheca weakly produced, posteroventral part not sclerotized, except long, single, weakly sclerotized triangular processes distally of phallic sclerite.

Key to male Helicopsyche from Vietnam

1. Maxillary palps each with two segments; gonopods without secondary branch...................................2

– Maxillary palps each with four segments; gonopods with secondary branch.......................................6

2.(1) In genitalia, basomesal lobe absent (as in Fig. 1C ).... H. boniata Malicky & Chantaramongkol, 1992

– In genitalia, basomesal lobe present ( Fig. 2C )......................................................................................3

3.(2) In genitalia, basomesal lobe originated from ventral part of gonopod basis, resembling secondary branch of gonopods (as in Schefter & Johanson 2001, figs 5, 9)........................................................4

– In genitalia, basomesal lobe originated from mid-height of gonopod basis ( Fig. 2C )........................5

4.(3) In genitalia, segment IX about as long as high; tergum X slender along its length in lateral view; in ventral view basomesal lobes fused mesally into common basal plate; in dorsal view, tergum X shallowly divided apically............................................... H. khemoiensis Schefter & Johanson, 2001

– In genitalia, segment IX much higher than long; tergum X wide and posteriorly tapering in lateral view; in ventral view basomesal lobes separated; in dorsal view, tergum X deeply divided apically...... ............................................................................................................... H. azwudschgal Malicky, 1995

5.(3) Sternite VI with sternal process about two-fifths as long as segment VI ( Fig. 3A ); posteroventral margin of segment IX produced posterad into large plate ( Figs 3C, E ); gonopods slightly sigmoid ( Fig. 3C )................................................................................................................... H. lamnata sp. nov.

– Sternite VI with sternal process about one-seventh as long as segment VI ( Fig. 2A ); posteroventral margin of segment IX not produced posterad ( Fig. 2E ); gonopods strongly sigmoid, bending about 90° ( Fig. 2C )................................................................................................................ H. meander sp. nov.

6.(1) In genitalia, dorsal branch of gonopods almost parallel-sided in lateral view.................................... ..................................................................................... H. admata Malicky & Chantaramongkol, 1992

– In genitalia, primary branch of gonopods widening distally in lateral view ( Fig. 1C )......................7

7.(6) In genitalia, primary branch of gonopods produced anterad ( Fig. 1C ).............. H. melina sp. nov.

– In genitalia, primary branch of gonopods produced posterad.............................................................8

8.(7) In genitalia, primary branch of gonopods shorter than secondary branch of gonopods; each lateral branch of tergum X divided apically............................................................... H. angusta Ulmer, 1951

– In genitalia, primary branch of gonopods longer than secondary branch of gonopods; each lateral branch of tergum X undivided apically.................................. H. dacklestenensis Schefter & Johanson, 2001

Figures

Fig. 3. Helicopsyche lamnata sp. nov., ♂ holotype. A. abdominal sternum VI, lateral view. B. abdominal sternal process VI, ventral view. C. genitalia, lateral view. D. genitalia, dorsal view. E. genitalia, ventral view. F. phallus, lateral view. G. phallus, ventral view.

Fig. 1. Helicopsyche melina sp. nov., ♂ holotype. A. abdominal sternum VI, lateral view. B. abdominal sternal process VI, ventral view. C. genitalia, lateral view. D. genitalia, dorsal view. E. genitalia, ventral view. F. phallus, lateral view. G. phallus, ventral view.

Fig. 2. Helicopsyche meander sp. nov., ♂ holotype. A. abdominal sternum VI, lateral view. B. abdominal sternal process VI, ventral view. C. genitalia, lateral view. D. genitalia, dorsal view. E. genitalia, ventral view. F. phallus, lateral view. G. phallus, ventral view.