Ambrysus montandoni La Rivers

Rodrigues, Higor D. D., Melo, Alan Lane De & Sites, Robert W., 2012, Redescription of Ambrysus montandoni La Rivers, 1963 (Hemiptera: Heteroptera: Naucoridae), with the first records for Brazil, Zootaxa 3357, pp. 63-68 : 65-67

Ambrysus montandoni La Rivers

( Figs. 1–8 )

Ambrysus montandoni La Rivers, 1963 : Biol. Soc. Nevada Occas. Pap. 1–5. Ambrysus montandoni: La Rivers 1965 : Biol. Soc. Nevada Occas. Pap. 5.

Ambrysus montandoni: Sites & Nichols 1999 : Proc. Entomol. Soc. Wash. 5–6.

Brachypterous male redescription ( Figs. 1–2 , 5–7 )

Dimensions (n=4): Length: 11.8–12.5; width across embolium: 7.6–8.0; head length: 2.0; width of head including eyes: 3.2–3.4; interocular space at middle: 1.7–1.9; length of pronotum: 2.1–2.2; maximum width of pronotum at posterolateral corners: 6.6–7.2; length of scutellum: 2.4-2.6; length of segments of fore leg, femur: 3.05–3.47; tibia: 2.43–2.65; tarsomere I: 0.50; middle leg, femur: 3.50–3.75; tibia: 3.30–3.60; tarsomeres I–III 0.36–0.40, 0.39–0.42, 0.63–0.75; hind leg, femur: 4.10–4.52; tibia: 5.20–5.55; tarsomeres I–III 0.43–0.50, 0.65–0.75, 1.25–1.30.

Coloration. Dorsally, head dark yellow to brown with a dark spot between eyes as inverted V; eyes black; labrum brownish yellow. Pronotum brown with small scattered brown to black spots; small longitudinal dark spot behind each eye; lateral margins yellow. Scutellum dark brown to black with brownish yellow antero-lateral corners. Embolium mostly yellow with apical fourth black. Corium and membrane black, with indistinct small brownish spots. Connexiva mostly yellow, III–V with anterior third brownish. Ventral surface and legs brownish mostly yellow, except middle region of pro- and mesopleura dark brown.

Head. Extended forward of the eyes with anterior margin subtruncate medially, depressed laterally in front of eyes. Eyes subglobose in shape and elevated above vertex. Labrum subtriangular, with anterior margin rounded.

Thorax. Pronotum forming indistinct V-shaped lines at its anterior margin; V open posteriorly and with small transverse grooves near anterior margin of head; lateral margins depressed with edges slightly elevated and posterolateral corner rounded. Hemelytra covered with fines tubercles, except posterior part of membrane. Scutellum with a line near anterior margin, irregular and concave medially, with few tubercles between this line and anterior margin. Embolium with lateral margin slightly elevated, basal one-third straight and apical two-thirds rounded, with nearly right angle formed by the posterior margin and embolar suture. Fore femur with large, dark tubercles on dorsal surface; anterior margin of fore trochanter with distinct tuft of setae; gold setae set in junction of propleura, just caudad of prosternum, continuing to mesosternum, close to mesocoxae; meso- and metatibiae with two distinct transverse rows of spines distally in ventral view; tibia and tarsi of middle and hind legs with small spines (less developed than in many congeners), but more developed in middle tibia; first tarsomere of middle and hind legs small; claws of middle and hind legs long, strongly curved, with basal tooth.

Abdomen. Connexivum exposed, with edges smooth; line of hairs dorsally near lateral margin with small tuft of elongate hairs posteriorly; posterolateral corners narrowly rounded, not acute. Venter densely pilose, except marginal band, embolium, median part of segments V–VIII naked, shining; large spiracle laterally in densely pilose area of each visible abdominal segment, 3–4 irregular glabrous areas immediately posterior to spiracle. Sternum V asymmetrical with concavity of posterior margin displaced to left. Mediosternite VI emanating from concavity of V and slightly directed to right. Tergite VI without accessory genital process, having no angle or posterior protuberance; asymmetrical, concave in right margin; tergite VII, pseudoparameres and tergite VIII symmetrical; pseudoparameres with apices directed laterally ( Fig. 5 ). Aedeagus elongate, with subparallel margins and maximum width near apex, left side of apex with a small process; parameres symmetrical; setae on lateral margins and apex of pygophore ( Fig. 6 ).

Brachypterous female description ( Figs. 3–4 , 8 )

Dimensions (n=4), Length 12.0–13.2; width across embolium: 7.8–8.1; head length: 1.9–2.0; width of head: 3.2–3.4; interocular space at middle of eye: 1.7–1.8; length of pronotum: 2.1–2.2; maximum width of pronotum: 6.9–7.2; length of scutellum: 2.5–2.6; length of segments of fore leg, femur: 3.00–3.25; tibia: 2.32–2.53; tarsomere I: 0.50; middle leg, femur: 3.50–3.75; tibia: 3.15–3.30; tarsomeres I–III 0.38, 0.42–0.45, 0.85; hind leg, femur: 4.43–4.50; tibia: 5.43–5.55; tarsomeres I–III 045–0.50, 0.57–0.67, 1.13–1.27.

Similar to brachypterous male in color and morphology. Genital operculum shining; depressed in middle with prominent rounded tubercle on each lateral margin near apex; deeply emarginated at apex, forming two rounded lobes; emargination continuing anteriorly as prominent carina for 1/4–1/3 length of genital operculum ( Fig. 8 ).

Intraspecific variation. We observed substantial variation only in the intensity of color, where some specimens were paler, thereby making the brownish spots of the hemelytra more evident. Possibly these variations exist due to the long time that these specimens were fixed in alcohol, which can be seen in Figures 1 and 3 of the dorsal habitus of the male and female. In addition, curvature of the lateral margin of the embolium differed between populations; it was nearly continuous in specimens from Venezuela, whereas the anterior 1/3 was nearly straight in specimens from Brazil.

Material examined. All specimens brachypterous. BRAZIL: 1 male, Roraima State, Yanomami indigenous area, Serra de Surucucu (02º49’53.78”N, 63º38’19.78”W), stream without name, 24.XI.1991, V. Py-Daniel and U. Barbosa coll., at INPA; 1 male, 2 females, same data, except collected in River of the waterfall, at INPA, except for 1 pair at DPIC; 1 male, 1 female, Yanomami indigenous area, Xitei/Xidéa indigenous park (02º36’20.54”N, 63º52’27.76”W), Igarapé das Irmãs, 17.XI.1993, V. Py-Daniel and U. Barbosa coll., at INPA. VENEZUELA: 4 males, 4 females, Amazonas State, S. Puerto Ayachucho, El Tobogan de la Selva (5º23.207’N, 67º36.922’W), 125 m, 14.I.2009, J. Camacho coll., VZ20090114-01, at MU; 1 male, Bolivar State, 108 km SW Sta. Elena de Uairén, blackwater stream, 04.VII.1987, R.S. Miller coll., at MU.

Discussion. The Brazilian specimens in this study are from west Roraima State, which borders the Territorio of Amazonas, southern Venezuela, the type is located is located. This species has not been recorded in Brazil previously ( Moreira et al., 2011); thus, this is the first record of A. montandoni for the Brazilian naucorid fauna. These localities in Brazil are situated between 800 and 1000 meters of elevation, as in the type locality at approximately 4,000 feet (1219 meters). In contrast, the Venezuelan specimens examined from El Tobogan de la Selva were collected at much lower elevation. Thus, elevation does not appear to be a limiting factor in the distribution of this species. Our specimens from Brazil were collected in rocky streams with fast currents, clinging to the stones; whereas the specimens from El Tobogan, Venezuela, were collected beneath leaves on a gently sloping, smooth granite bedrock stream.

La Rivers (1963) referred to A. montandoni and Ambrysus maldonadus La Rivers, 1954 , as “square species” in reference to their divergent shape from that of congeners. He also distinguished these species by the condition of the “procts” (= pseudoparamere) and the absence of the male accessory genitalic process of the 6th tergum. Further, he commented that these two species are superficially similar, but after deeper analysis he noticed that they had many characteristics that differ. We found the most remarkable interspecific differences to be the tuberculate hemelytra in A. montandoni ; length of the propleural junction being distinctly less than the length of the prosternum in A. montandoni , whereas these distances are subequal in A. maldonadus ; and the pseudoparameres being brown, more elongate, and with sides parallel in A. montandoni , whereas they are black and with sides converging in A. maldonadus . In the original description of A. maldonadus, La Rivers (1954) suggested that this species could form a monotypic group of Ambrysus primarily because of the distinct pseudoparameres and the genital operculum of the female, and together with Ambrysus montandoni, La Rivers (1963) more specifically suggested they might represent a distinct subgenus. However, the currently recognized subgeneric assignments in Ambrysus were brought into question with morphometric analyses by Sites & Willig (1994), whose results did not support the current subgeneric associations. The currently recognized subgenera ( La Rivers 1965) are based on indiscriminately chosen morphological similarities and not on a phylogenetic approach. Thus, although A. montandoni and A. maldonadus have a unique shape and possess similarly developed pseudoparameres, additional features including molecular data and a robust phylogenetic analysis are needed to resolve the evolutionary relationships of these species with other taxa of Ambrysus and Cryphocricinae .

Figures

FIGURES 1 – 4. Ambrysus montandoni. (1) Dorsal and (2) ventral habitus of the male, (3) dorsal and (4) ventral habitus of the female.

FIGURES 5 – 8. Ambrysus montandoni. (5) Dorsal view of the terminal abdominal segments of the male, (6) male genital capsule with aedeagus and parameres, (7) right paramere, (8) ventral view of the terminal abdominal segments of the female.