Rasahus nesiotes, Swanson, 2018

Swanson, Daniel R., 2018, Three new species of Rasahus, with clarifications on the identities of three other Neotropical corsairs (Heteroptera: Reduviidae: Peiratinae), Zootaxa 4471 (3), pp. 446-472 : 450-451

Rasahus nesiotes sp. nov.

( Fig. 1 )

Diagnosis: Easily separated from all other species of Rasahus by the small size, the black connexiva, and the presence of a small pale macula occupying the apex of the medial cell of the hemelytral membrane.

Coloration: Black, except the following reddish-testaceous: all antennal segments (lighter apically), femora to tarsi of all legs (but these, especially the femur, suffused with both slightly lighter red and black), and fossula spongiosa of protibia and mesotibia. Connexiva and abdominal tergites suffused with dark castaneous. Second and third rostral segment also slightly lighter, becoming dark castaneous but may be due to preservation. The following spots of the hemelytra tawny or luteous: apical third of clavus, adjacent portion of corium covering apical half of claval margin, faint short vitta on membrane adjacent to corial apex, and oval spot well-contained in medial cell of membrane.

Structure: Anteocular region covered on all surfaces with short silvery pile. Interocular region with width subequal to width of eye, with setae and silvery pile dorsally. Postocular region with short longitudinal sulcus reaching cephalad from transverse sulcus. Neck laterally and ventrally with short pile.

Antennae: as per description under Rasahus .

Eyes in lateral view nearly reaching dorsal margin and not reaching ventral margin.

Ocelli moderate-sized, slightly raised, separated from each other by slightly more than diameter of one ocellus and from eye by approximate width of one ocellus.

Rostrum: as per description under Rasahus .

Pronotum: Anterior pronotal lobe with sulci distinct and granulate within, sparse short and long setae in sulci. Posterior pronotal lobe with small granules immediately posterior to transverse pronotal suture on apical third of disc medially, this granulate area diminishing laterally, otherwise smooth, with few scattered setae near lateral and posterior margins.

Scutellum obscured by pin, apex prolonged in apically-rounded spine.

Pleura: Propleuron with integument granulate, delimited laterally from dorsal face by distinct carina. Mesopleuron with integument more sparsely granulate. Metapleuron with integument conspicuously granulate, glabrous except coxal sheath densely silvery pilose, metapleural sulcus narrow between carinae.

Sterna: Metasternum convex medially, more or less rounded posteriorly.

Hemelytra reaching apex of seventh tergite, base of corium (usually veins) and outer margin of clavus with rows of distinct black setae.

Forelegs: Profemur with ventral setae arranged in two rows. Protibia slightly thickened apically, with thick brush of setae at anterior face at apex, fossula spongiosa long, covering almost three-fourths length of tibia.

Middle legs: Tarsus with thick black spinose setae ventrally, second tarsal segment longest. All else as forelegs.

Hind legs: as per description under Rasahus .

Abdomen with connexiva with long thin seta at posterolateral angle, disc of seventh ventrite densely pubescent.

Female genitalia: Of general peiratine form. Visible portion of eighth tergite short, posterior margin convex. Ninth tergite trapezoidal. Tenth tergite trapezoidal to subtriangular, apex subrounded. Lobes of valvifer 1 (=part of eighth segment) hemispherical. Valvulae 1 somewhat elongate, convex apicolaterally, apex roundly acute. All segments with integument smooth (except few rugulae ventrally on valvifer 1), lacking spines or tubercles, with abundant short pale appressed pubescence and sparse scattered long semi-erect setae. Tenth tergite with long golden setae of moderate length, more densely so along lateral and apical margins.

Male: unknown.

Measurements (in mm): total length (apex of head to apex of hemelytra): 13.3; head length: 2.4; head width (across eyes): 1.5; anteocular length: 1.2; postocular length: 0.4; neck length: 0.4; scape length: 1.0; pedicel length: 2.1; basiflagellum length: 2.2; distiflagellum length: 2.3; antennal segment ratio: 1.0: 2.1: 2.2: 2.3; eye length: 0.8; eye width: 0.5; rostral segment 1 length: 0.9; rostral segment 2 length: 1.5; rostral segment 3 length: 0.9; rostral segment ratio: 1.0: 1.7: 1.0; prothorax length: 3.2; prothorax width (across humeri): 3.2; anterior pronotal lobe length: 2.3; posterior pronotal lobe length: 0.9; scutellum length: 1.6; scutellum width (at base): 1.4; hemelytra length: 8.7; procoxa length: 1.7; protrochanter length: 0.9; profemur length: 3.1; protibia length: 2.8; protibial fossula spongiosa length: 2.6 (0.6 of which overhangs tibial apex); protarsi length: 1.2; protarsal segment ratio: approximately 1.0: 1.5: 1.7; mesocoxa length: 0.7; mesotrochanter length: 0.7; mesofemur length: 2.9; mesotibia length: 2.5; mesotibial fossula spongiosa length: 2.1; mesotarsi length: 1.4; mesotarsal segment ratio: approximately 1.0: 2.0: 1.5; metacoxa length: 1.0; metatrochanter length: 1.0; metafemur length: 4.1; metatibia length: 4.4; metatarsi length: 2.4; metatarsal segment ratio: approximately 1.0: 3.0: 2.0; abdomen length: 7.1; abdomen (widest) width: 4.1.

Material examined: [ THE BAHAMAS:] Grand Bahama Island: 27–28 December 1965, R. D. Alexander [1 female, holotype] ( UMMZ).

Distribution: Known only from the type locality ( Fig. 4 ).

Etymology: The specific epithet, a noun in apposition, comes from the Greek νησιώτης, Latinized nesiotes , ‘islander’ and references the type locality.

Remarks: This species is easily referred to the complex of species with a circular macula well-contained in the medial cell of the hemelytral membrane (= hamatus group; see Key to Species of Rasahus and Froeschnerisca ). This group consists of R. amapaensis , R. angulatus , R. arcitenens , R. arcuiger , R. argentinensis , R. biguttatus , R. grandis , R. hamatus , R. limai , R. thoracicus , and R. scutellaris stat. rev. (see next section).

Among these, it seems that R. nesiotes sp. nov. is most closely related to R. hamatus , based on a more similar color pattern, including the lack of a pale arcuate spot of the cubital cell and the black costal margins, as well as close geographical proximity. However, R. nesiotes sp. nov. differs from R. hamatus in various ways. First, the female holotype of R. nesiotes sp. nov. (ca. 13 mm) is much smaller than females of R. hamatus (17–18 mm). The spots of the hemelytra differ subtly as well. In R. nesiotes sp. nov., the postscutellar macula is limited to the apical third of the clavus and is essentially obsolete in the basal third of the adjacent part of the corium. Conversely, the postscutellar macula occupies the apical half of the clavus and reaches to the bases (although narrowed) in the adjacent region of the corium in R. hamatus . The round spot of the membranal medial cell also differs in size between the two species, being smaller and clearly not occupying most of the cell in R. nesiotes sp. nov. versus essentially filling the cell in R. hamatus . Lastly, the connexiva of R. nesiotes sp. nov. are wholly black, whereas they are either wholly stramineous (males) or distinctly bicolorous yellow-black (females) in R. hamatus .

This is the only peiratine species currently known from the Bahamas.

Figures

FIGURE 1. Rasahus nesiotes sp. nov., adult female (holotype): (A) dorsal habitus; (B) lateral habitus; (C) pronotum, dorsal view; (D) terminalia, caudal view; (E) labels. Scale bar = 2 mm.

FIGURE 4. Map indicating type locality of Rasahus nesiotes sp. nov., R. deliquus sp. nov., and R. abolitus sp. nov.