Eotrechus boukali, Tran & Zettel & Sites, 2023

Tran, Anh Duc, Zettel, Herbert & Sites, Robert W., 2023, Revision of the genus Eotrechus Kirkaldy (Hemiptera, Heteroptera, Gerridae), with descriptions of six new species, Deutsche Entomologische Zeitschrift 70 (1), pp. 69-111 : 69

Eotrechus boukali sp. nov.

Figs 18 , 19 A-J , 24

Material examined.

Holotype: Myanmar • ♂ (apterous); Sagaing Division, Alaungdaw Katthapa National Park, Pagoda stream; 22°19.113'N, 94°28.518'E; 350 m a.s.l.; 5 May 2003; Boukal et al. leg; (105); NHMW.

Paratypes: Myanmar • 1 ♂, 2 ♀♀ (apterous); same locality data as holotype; NHMW • 2 ♂♂, 1 ♀ (apterous); Sagaing Division, Alaungdaw Katthapa National Park, Pagoda stream; 22°19.094'N, 94°28.823'E; 350 m a.s.l.; 6 May 2003; Boukal et al. leg.; (110); NHMW .

Description.

Size: apterous males, length 5.70-5.80 (holotype 5.79), width 1.77-1.87 (holotype 1.76); apterous females, length 6.30-6.95, width 2.13-2.25.

Colour (Fig. 18A, B ). Apterous form, dorsum of body mainly yellowish-brown to dark-brown with brown markings on thorax, covered with silvery and golden pubescence; venter yellowish. Head with one narrow median longitudinal dark-yellow stripe and two dark-brown marks laterally to the median stripe, anterolateral corners and posterior margin of head yellow. Antennae yellow to brown, segment I yellow, segment II yellow or brown, segments III, IV brown. Pronotum with a median longitudinal yellow stripe and two dark-brown paramedian marks, yellow laterally. Mesonotum mainly yellowish-brown with a median longitudinal yellow stripe and two dark-brown marks laterally to the median stripe, anterosublateral areas with two yellow marks, anterolateral areas dark-brown. Metanotum and abdominal tergum mainly dark-brown, with narrow median longitudinal dark-yellow stripe on terga III-VII, connexiva brown or yellowish-brown. Pro- and mesopleura yellowish with longitudinal brown stripe; mesopleura with stripe of silvery and reflective pubescence next to and ventrally to brown stripe; apical part of pro-, meso- and metacetabula dark-brown, partially covered with patches of dense silvery and reflective pubescence. Legs with all coxae, trochanters and femora yellow, all tibiae and tarsi yellowish-brown or brown.

Structural characteristics: Apterous male (holotype): Head width across eyes 1.49; interocular width 0.57; eye kidney-shaped in dorsal view, length of eye 0.69. Antennae ca. 1.3 × body length (7.67: 5.79), lengths of segments I-IV: 1.87: 1.58: 1.58: 2.64; segment I usually with 5-6 black spines in apical part. Pronotum broader than long, shorter than head length (0.75: 1.19). Lengths of mesosternum and metasternum: 1.87 and 0.48; posterior margin of metasternum raised in the middle. Lengths of leg segments (femur: tibia: tarsal segment I: tarsal segment II) as follows: fore leg: 2.46: 2.24: 0.23: 0.39; middle leg: 5.89: 5.17: 0.41: 0.48; hind leg: 6.08: 6.54: 0.32: 0.41. Fore leg (Fig. 19A ): trochanter with few long, fine setae; femur moderately thickened at basal part and gradually tapering towards apex, length ca. 6.2 × maximum width (2.46: 0.40), flexor side with only one stout seta at basal part and a few fine, long setae; tibia straight, with long, brown stout setae on apical margin; tarsus covered with long, soft, yellowish setae (denser on ventral surface). Middle and hind femora slender and slightly longer than body; middle and hind femora, middle and hind tibiae with scattered, short, brown, stout setae. Claws stout, lengths of fore, mid- and hind claws: 0.18: 0.19: 0.17. Abdomen short, total length of abdominal sterna II-VII: 1.23, sternum II distinctly raised in the middle, sterna III-V medially grooved. Sternum VII slightly longer than length of two preceding sterna combined (0.39: 0.35), posterior margin with a median notch (ca. 0.25 × the length of sternum VII) (Fig. 19B ). Genitalia (Figs 18C, D , 19D-H ): small, pygophore in ventral view truncate posteriorly, with posterolateral corners produced into small lobes (or rounded in sample from location 22°19.094'N, 94°28.823'E) bearing long, yellowish setae; paramere small and blunt; proctiger simple, elongate, with apex acute and bearing long, yellowish setae.

Apterous female: Head width across eyes 1.50; interocular width 0.61; eye kidney-shaped in dorsal view, length 0.68. Antennae ca. 1.1 × of body length (7.12: 6.30), lengths of segments I-IV: 1.75: 1.47: 1.38: 2.52; segment I with 4-5 black spines subapically. Pronotum slightly shorter than head length (0.72: 1.08). Lengths of mesosternum and metasternum: 1.87 and 0.58. Lengths of leg segments (femur: tibia: tarsal segment I: tarsal segment II): fore leg: 2.22: 2.00: 0.26: 0.40; middle leg: 5.69: 4.85: 0.50: 0.47; hind leg: 5.95: 5.31: 0.41: 0.43. Fore leg (Fig. 19C ): trochanter with two or three long, stout setae on ventral side; femur moderately thickened at basal part and gradually tapering towards apex, length ca. 6.3 × maximum width (2.22: 0.35), along flexor side with a row of 12-15 stout, black setae of irregular length, some as long as greatest width of fore femur; tibia straight with 10-14 scattered, long, stout setae on extensor surface and long, black spines on apical margin; tarsus covered with long, soft, yellowish setae (denser on ventral surface). Middle and hind femur slender and subequal to body length; middle and hind femora, middle and hind tibiae with scattered, short, brown spines. Claws stout, lengths of fore, mid- and hind claws: 0.18: 0.21: 0.21. Total length of abdominal sterna II-VII ca. 0.3 × body length (2.04: 6.30). Sternum VII ca. 1.6 × length of two preceding sterna combined (0.85: 0.54), posterior margin straight. Connexival corners of sternum VII curved mesad and with tuft of long, golden setae directed mesad. Genitalia not totally concealed by sternum VII, part of gonocoxae and proctiger still visible in lateral and ventral views; proctiger elongate, with cone-shaped apex and directed posterodorsad (Fig. 19I, J ).

Macropterous morph: unknown.

Remarks.

Eotrechus boukali sp. nov. is most similar to E. hygropetricus in the following characteristics: the fore femur of both sexes is widest at the basal part and gradually tapering towards the apex; the fore femur of the female has a row of long, stout setae on the flexor side; the proctiger of the female is elongate and with a cone-shaped apex; the genitalia of the female is not totally concealed in lateral view of the abdomen; however, this new species can be easily distinguished from the latter by the following: In E. boukali sp. nov., the fore femur of the male has no long, stout setae on the flexor side; abdominal sterna III-V of the male have a distinct median, longitudinal groove; the pygophore is truncate in ventral view, with posterolateral corners rounded or produced in to small lobes; sternum VII of the female is distinctly longer than the two preceding sterna combined; the proctiger of the female is directed posterodorsad. In E. hygropetricus , the fore femur of both sexes has long, stout setae on the flexor side; the male pregenital abdomen is only slightly impressed in the middle; the pygophore is simple, with a rounded posterior margin in ventral view; sternum VII of the female is subequal in length to the two preceding sterna combined; the proctiger of the female is directed almost straight caudad ( Andersen 1982). Note that the apterous morph of E. hygropetricus is still unknown; thus, it is not possible to determine whether the apterous female of this species has the tuft of long, golden setae on the connexival corners of sternum VII. If not, this structure might be unique for E. boukali sp. nov., in comparison with its congeners.

Body size and general dorsal colour pattern of E. boukali sp. nov. resemble that of E. vietnamensis Tran & Yang, 2006 and E. pumat J. Polhemus, Tran & D. Polhemus, 2009. However, this new species is clearly different from these species in the following characteristics: the pronotum and mesonotum lack sublateral, brown marks; the fore femur (both sexes) gradually tapers towards the apex (whereas in E. vietnamensis and E. pumat , it is clearly constricted at the apical part); the fore femur of the female has a row of ca. 12 long, stiff setae along the flexor side and the fore femur of the male lacks stiff setae (Fig. 19A, C ) (whereas in both sexes of E. vietnamensis and E. pumat , the flexor side of the fore femur has only 2-5 stiff setae at basal part); the posterior margin of sternum VII of the male has a wide and shallow median notch (whereas in E. vietnamensis and E. pumat , the median notch on sternum VII is narrower and deeper); the pygophore is simple, less modified, without prominent posterolateral processes (Figs 18C, D , 19D-F ); the connexival corner of sternum VII of the female has a tuft of long, golden setae (Fig. 19I, J ).

Etymology.

This species is dedicated to Czech scientist Dr David Boukal from the University of South Bohemia who collected the type series.

Distribution.

Myanmar: Sagaing Region (Fig. 24 ).

Figures

Figure 18. Eotrechus boukali sp. nov. A, B. Habitus; A. Apterous male; B. Apterous female; C. Pygophore, dorsal view; D. Proctiger, dorsal view (A, B. Same scale; C, D. Same scale).

Figure 19. Eotrechus boukali sp. nov. (A-J) and E. hygropetricus (K). A. Right fore leg of male; B. Abdomen of male, ventral view (excluding genital capsule); C. Right fore leg of female; D, G. Genital capsule, lateral view; E, H. Genital capsule ventral view; F. Genital capsule, dorsal view (D-F. Paratype from location 22 ° 19.113 ' N, 94 ° 28.518 ' E; G, H. Paratype from location 22 ° 19.094 ' N, 94 ° 28.823 ' E); I, K. Abdomen of female, lateral view; J. Abdomen of female, lateral view (A, B, I-K. Same scale; D-H. Same scale).

Figure 24. Distribution records of species of Eotrechus. Squares represent E. brevipes species group; circles represent E. hygropetricus species group.