Australambrysus aguaro Sites, 2023

Sites, Robert W., 2023, The Australambrysus plax (La Rivers, 1967) species complex (Heteroptera: Naucoridae), with descriptions of three new species, Zootaxa 5278 (2), pp. 318-332 : 323-326

Australambrysus aguaro Sites NEW SPECIES

( Figs. 6 , 9 )

Description. Macropterous female. HOLOTYPE, length 7.28; maximum width 4.08. Paratype (n = 1), length 7.04; maximum width 4.00. General shape elliptical; widest across embolia ( Fig. 6a ). Dorsal coloration of head, pronotum, and legs yellowish-brown; hemelytra dark-brown. Dorsal surface coarsely punctate. Ventral coloration of head and thorax brownish-orange, abdomen with dense golden pubescence.

Head. Head length 1.22; maximum width 1.70. Mostly yellow anteriorly, yellowish-brown posteriorly, with two paramedian rows of dark-brown punctures. Eyes convergent anteriorly, synthlipsis 0.72; thin band of cuticle along posterolateral margin of eye; eyes not raised above level of vertex or pronotum. Anterior margin between eyes slightly convex, extending anteriorly in front of eyes 8% of head length; posterior margin between eyes strongly convex, extending posteriorly 39% of head length. Labrum width 2.1 length, evenly rounded. Labium with three visible yellowish-brown segments, darkening distally, extending 0.360 beyond labrum not including extruded stylets. Antennal proportions 3:5:11:6, length 0.44, extending to near lateral margin of eye, elongate hairs on segment 4 and distal half of 3.

Thorax. Pronotum coarsely punctate, ground color yellowish-brown; transverse sulcus and nearly confluent series of dark-brown punctures marking anterior border of transverse band in posterior 1/4; cuticle irregularly darkened adjacent to posterolateral margin of eye; lateral margins with few dark-brown punctures, convergent, shallowly convex, explanate; posterior margin straight; anterior margin deeply concave between eyes to embrace convex posterior margin of head; posterolateral corner truncate, thus with two obtuse angles and straight margin between angles ( Fig. 6a ); width 3.4 length; length at midline 1.04; maximum width at anteriormost posterolateral angle 3.56. Prothorax ventrally pruinose throughout; apices of propleura meeting at midline and concealing much of prosternellum, closely appressed to margins of probasisternum; propleuron orange-brown throughout, but darker along posterior margin; medial 2/3 of posterior margin with elongate golden setae. Probasisternum with sharp median carina, with row of short setae lateral to carina. Scutellum coarsely punctate, triangular, mostly orange-brown, width 1.9 length, width 2.24, length 1.16. Hemelytra densely punctate, medium-brown, extending to near end of abdominal terga, length 5.20 (chord measurement). Clavus with thin, yellow transverse stripe at base; intraclaval suture well-developed; claval commissure length 0.70. Embolium length 2.24, greatest width 0.64; lateral margin convex, yellowish in anterior 3/4, medium-brown posteriorly. Oblique suture connecting claval and embolar sutures near bases. Hind wings extending to middle of tergum VI. Mesobasisternum midventral tumescence negligible, with sulcus on midline continuing through triangular mesosternellum. Metasternellum (= metaxyphus) transverse, posterior margin concave laterally with apex acute.

Legs. All legs segments yellowish-brown. Profemur posterior margin with row of tightly arranged setae in proximal 2/3, row of short brown spines along middle third, spines generally single proximally becoming small combs of two to three spines distally; anterior margin with dense pad of setae without associated spines. Protibia and tarsus with occlusal inner surface flattened; tarsus immovable, one-segmented; pretarsal claw single, minute, triangular. Procoxa with row of brown, elongate anteromedial setae. Meso- and metacoxae partially recessed into thorax. Meso- and metafemora with row of short, brown spines on anterior margin; spines restricted to basal half on mesofemur, nearly full-length, but sparse and in combs of two to three on metafemur. Mesotibia with ventrolateral, ventromedial, dorsolateral, and dorsomedial rows of stout reddish-brown spines; ventromedial and dorsomedial rows intermixed with combs of two to four spines. Metatibia with ventrolateral, ventromedial, dorsolateral, and dorsomedial rows of stout reddish-brown spines. Meso- and metatibia with semi-circlets of spines at apex of dorsal and mesal margins; two comb rows of stout spines near apex of ventral margin. Long, pale swimming hairs on femora and tibiae of middle and hindlegs and metatarsi; hairs profuse on metatibia and -tarsus. Meso- and metapretarsi with paired claws slender, gently curved, with small basal tooth. Leg measurements as follows: foreleg, femur 1.90, tibia 1.72, tarsus 0.40; middle leg, femur 1.96, tibia 1.70, tarsomeres 1–3, 0.12, 0.28, 0.40; hind leg, femur 2.60, tibia 2.34, tarsomeres 1–3, 0.15, 0.46, 0.52.

Abdomen. Dorsally with lateral margins of III–VIII exposed, margins of III–VI each dark in anterior-half and light in posterior half; lateral margin smooth to shallowly serrate, group of trichobothria near posterolateral corners. Posterolateral corners of II (visible ventrally) –III right angled, IV–VI acute and spinose. Posterior margin of left laterosternite VI with short spine approximately half size of posterolateral spine ( Fig. 6e arrows). Ventrally entirely golden brown, with dense pile of fine hairs. Lateral margin with thin, glabrous band. Glabrous elliptical patches near spiracles evident on laterosternites II–VII. Mediosternite VII (subgenital plate) with lateral margins convergent to broadly rounded posterior margin; apex with semicircular median notch 1.5 wider than deep; subgenital plate width 0.93 length; length at midline 0.94; maximum width 0.87 ( Fig. 6e ).

Macropterous male. Paratype (n = 1), length 7.12; maximum width 4.08. Similar to female in general structure and coloration except as follows: Hemelytra surpassing posterior margin of tergum V. Accessory genitalic process of tergum VI absent. Medial lobes of tergum VIII (pseudoparameres) slightly asymmetrical, posterolateral corner anteriorly displaced ( Fig. 6c arrow), posterior margin continuously convex from anteriorly set posterolateral corner to straight medial margin, ( Fig. 6c ). Aedeagus elongate, linear, with acuminate apex ( Fig. 6b ); ventral lobes membranous. Parameres symmetrical, stout, and broad, apical lobe as long as wide, with stout spines along distal half of mesal margin, apex rounded, anterior margin shallowly concave, posterior corner right angled and hyaline ( Fig. 6d ). Proctiger short, length 0.5 width. Pygophore with elongate setae sparsely distributed over most of surface, with thick brush of elongate setae on posterior margin, anterior margin convergent to narrowly rounded apex ( Fig. 6b ).

Brachypterous male and female. Unknown.

Diagnostic features. Australambrysus aguaro n.sp. has a short spine on the posterior margin of female left laterosternite VI ( Fig. 6e ), which differs from A. alvarado n.sp. which lacks a spine ( Fig. 7e ). Males of A. aguaro n.sp. can be distinguished from those of A. alvarado n.sp. and A. clavieri n.sp. by the relatively shorter, broader parameres (compare Figs. 6d , 7e , 8b ); and by the medial lobes of tergum VIII continuously rounded from the anteriorly displaced posterolateral corner ( Fig. 6c arrow) to the medial margin, whereas those of A. clavieri n.sp. are broadly rounded only on the posteromedial corner and meet the lateral lobe at a right angle ( Fig. 8c ) and those of A. alvarado n.sp. are subquadrate with a subtle lobe on the otherwise relatively straight posterior margin ( Fig. 7d ).

Discussion. This species was collected with the saucer bugs Limnocoris pusillus Montandon, 1897b , Limnocoris reynosoi Rodrigues & Sites, 2021 , and Placomerus obscuratus Sites & Camacho, 2014 at the type locality. Australambrysus aguaro n.sp. is known from only Venezuela, although two similar specimens from Guyana have a female with a short spine on the posterior margin of left laterosternite VI and a male with parameres resembling those of Australambrysus alvarado n.sp.

Etymology. The specific epithet is a noun in apposition and refers to the river in which the type series was collected.

Type depository: Museo del Instituto de Zoologia Agrícola , Maracay, Venezuela .

Type material examined. HOLOTYPE ♀. VENEZUELA: Guárico: UCV San Nicolasito Field Stn, Ro Aguaro, 86.226’N, 6626.228’W, 52 m, 10 January 2009, colls: Short , Garcia , Camacho , Miller , Joly, VZ 09-0110- 01A ( MIZA) . PARATYPES: same data as holotype (1♁, 1♀ UMC) .

Additional material examined. Same data as holotype (1♀, DNA-extraction #H2 UMC) .

Figures

FIGURE 6. Australambrysus aguaro n.sp. (a) Dorsal habitus of holotype, (b) genital capsule with terga IX and X removed, (c) male abdominal tergum VIII, arrow indicates anterolateral corner of pseudoparamere, (d) left and right parameres, (e) terminal abdominal sterna of female, arrows indicate spines on left laterosternite VI (apical terga removed digitally). ae = aedeagus, pr = paramere, sgp = subgenital plate.

FIGURE 7. Australambrysus alvarado n.sp. (a) Dorsal habitus of holotype, (b) genital capsule with terga IX and X removed, (c) left and right parameres, (d) male abdominal tergum VIII, (e) terminal abdominal sterna of female (apices of terga and hemelytra removed digitally), (f) type locality of Río Alvarado with rootmat habitat in inset.

FIGURE 8. Australambrysus clavieri n.sp. (a) Dorsal habitus of holotype, (b) left and right parameres, (c) abdominal tergum VIII, (d) genital capsule with terga IX and X removed.

FIGURE 9. Distribution records of species in the Australambrysus plax species complex.