Amemboides falcatus, Tran & J. Polhemus, 2009

Tran, A. D. & Polhemus, J. T., 2009, Two new species of the genus Amemboides Polhemus & Andersen, 1984, stat. nov. (Hemiptera: Heteroptera: Gerromorpha: Gerridae) from Vietnam, Zootaxa 2216, pp. 49-56 : 52-53

Amemboides falcatus , sp. nov.

( Figs. 1–6)

Material examined. Holotype (apterous male) and allotype (apterous female), Vietnam, Da Nang Prov., Ba Na-Nui Chua, Suoi Vong Nguyet, coll. Tran A.D. & Tan H.H., 01 Mar. 2005, THH05-24 ( ZMHU).

Paratypes: VIETNAM: Da Nang Prov.: 1 male (apterous), same as holotype locality data ( ZMHU) ; 5 males (apterous), Ba Na - Nui Chua, Suoi Nai - Thac Cau Vong, coll. Tran A.D., 26 May 2003, TAD0334 ( ZRC) ; 2 males (apterous), Ba Na - Nui Chua, Suoi Nai - Thac Cau Vong, coll. Tran A.D. & Tan H.H., 01 Mar. 2005, THH05-23 ( ZRC) .

Description. Size (all apterous): males, length 4.0–4.8 (holotype: 4.5), width 1.40–1.56 (holotype: 1.56); female (allotype), length 4.8, width 1.83.

Colour. Apterous form, body mainly yellowish brown, with faint brownish markings on dorsum (brown markings paler in female); head with median light stripe; pronotum and mesonotum with distinct median light stripe, marginated with light brown markings; lateral sides and submedian part with expanded faint brownish markings; brown lateral stripe on mesonotum, about 3/5 of length, running from anterior margin; metanotum dark brown, covered with golden pubescence; terga 1 and 2 and connexival margins dark brown; dorsum of abdomen with scattered golden pubescence; silvery spots as typical for genus (on mesoacetabula and metaacetabula). Venter light yellowish.

Apterous male: Head width 0.92, interocular width 0.51, eye length 0.42. Lengths of antennal segments 1–4: 1.03: 0.98: 1.14: 1.51. Pronotum length: 0.60, mesonotum length: 1.27. Mesosternum length: 1.57, metasternum length: 0.32. Lengths of leg segments (femur: tibia: tarsus 1: tarsus 2): front leg: 1.74: 1.56: 0.13: 0.29; middle leg: 3.77: 2.54: 0.56: 0.43; hind leg: 3.19: 1.56: 0.32: 0.37. Pregenital abdomen length 0.59. Genital segments relatively long: abdominal segment 8: dorsal length: 0.54, ventral length: 0.54, on ventral view, slightly longer than all preceding abdominal sterna combined ( Fig. 2). Pygophore with slightly emarginated hind margin, minus process next to the base of paramere ( Figs. 3, 4). Proctiger long, slender, slightly constricted at middle part ( Fig. 6). Paramere long, falcate, with long scattered hairs, curved at 1/3 distal part, rounded apex ( Fig. 5).

Apterous female: Head width 0.98, interocular width 0.56, eye length 0.41. Lengths of antennal segments 1–4: 1.11: 0.98: 1.21: 1.35. Pronotum length: 0.57, mesonotum length: 1.71. Mesosternum length: 2.01, metasternum length: 0.44. Lengths of leg segments: front leg: 1.72: 1.59: 0.14: 0.33; middle leg: 4.21: 2.81: 0.60: 0.46; hind leg: 3.33: 1.74: 0.33: 0.40. Pregenital abdomen length: 1.16, sternite 7 length: 0.46, abdomen straight, sternite 7 not slanted downwards, connexival angles rounded.

Etymology. This species is named after the falcate shape of the male paramere.

Remarks. Amemboides falcatus is closely related to A. sexualis Polhemus & Andersen, 1984 . It shares with the latter species the following characteristics: falcate paramere, slender and constricted proctiger, apically emarginated pygophore, rounded connexival angles in female. However, it can be separated from A. sexualis by shorter genital segments (very long in A. sexualis ), paramere curved at distal ⅓ (curved at distal ½ in A. sexualis ), pygophore only slightly emarginated, not distinctly bifid apically and without long hair tufts laterally, female hind femur without long hairs basally, female sternite 7 not slanted downwards. Females of A. falcatus show an intermediate combination of characters between the two subspecies A. velaris velaris (sensu Polhemus & Andersen, 1984) and A. velaris orientalis (sensu Zettel & Chen, 1997): the shape of abdominal segment 7 is similar to that of A. velaris orientalis but the short and sparse hairs on the connexival margin are as in A. velaris velaris ; the absence of long black hairs on hind margins of terga 5–7 is similar to A velaris orientalis (whereas these structures are present in A. velaris velaris ).

Distribution. Vietnam: Da Nang.