Australambrysus alvarado 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 : 326-329

Australambrysus alvarado Sites NEW SPECIES

( Figs. 1a , 7 , 9 )

Description. Macropterous male. HOLOTYPE, length 8.16; maximum width 4.80. Paratypes (n = 9), length 8.08– 8.64 (mean = 8.39); maximum width 4.72–5.12 (mean = 4.94). General shape elliptical; widest across embolia ( Fig. 7a ). Dorsal coloration of head, pronotum, and legs yellowish-brown; hemelytra dark-brown. Dorsal surface coarsely punctate. Ventral coloration of head and thorax medium-brown, abdomen with dense golden-brown pubescence.

Head. Head length 1.40; maximum width 1.94. Mostly yellowish-brown, with medium-brown midline stripe and two paramedian rows of dark-brown punctures. Eyes convergent anteriorly, synthlipsis 0.79; 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 10% of head length; posterior margin between eyes strongly convex, extending posteriorly 36% of head length. Labrum width 2.0 length, evenly rounded. Labium with three visible yellowish-brown segments, darkening distally, extending 0.40 beyond labrum not including extruded stylets. Antennal proportions 2:5:10:7, length 0.48, 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 without 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. 7a ); width 3.0 length; length at midline 1.44; maximum width at anteriormost posterolateral angle 4.32. Prothorax ventrally pruinose throughout; apices of propleura meeting at midline and concealing part of prosternellum, closely appressed to margins of probasisternum; propleuron orange-brown throughout, but darker along lateral and posterior margins; medial 4/5 of posterior margin with elongate golden setae ( Fig. 1a ). Probasisternum with sharp median carina, with row of short setae lateral to carina ( Fig. 1a ). Scutellum coarsely punctate, triangular, entirely brown with yellowish-brown at apex, width 1.9 length, width 2.80, length 1.44. Hemelytra densely punctate, dark-brown, surpassing apex of tergum V, length 5.92 (chord measurement). Clavus with thin, yellow transverse stripe at base; intraclaval suture well-developed; claval commissure yellowish-brown, length 0.76. Embolium length 2.52, greatest width 0.76; lateral margin convex, light-brown in anterior 2/3, dark-brown posteriorly. Oblique suture connecting claval and embolar sutures near bases. Hind wings extending to middle of tergum V. Mesobasisternum midventral tumescence negligible, with sulcus on midline continuing through triangular mesosternellum. Metasternellum (= metaxyphus) transverse, posterior margin concave laterally with apex rounded and obtuse.

Legs. All legs segments brownish-yellow. 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 five 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 four 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 2.04, tibia 1.92, tarsus 0.38; middle leg, femur 2.20, tibia 1.94, tarsomeres 1–3, 0.22, 0.34, 0.36; hind leg, femur 2.60, tibia 3.08, tarsomeres 1–3, 0.18, 0.46, 0.56.

Abdomen. Dorsally with lateral margins of III–VIII exposed, each margin dark-brown in anterior-half and yellowish-brown in posterior half ( Fig. 7a ); lateral margin smooth to shallowly serrate, sparse marginal row of short yellow setae, group of trichobothria near posterolateral corners. Posterolateral corners of II (visible ventrally) –III right angled, IV–VI spinose, VII short and acute. Accessory genitalic process of tergum VI absent. Medial lobes of tergum VIII (pseudoparameres) subquadrate, medial margin straight, posterior margin straight to shallowly convex and with small lobe ( Fig. 7d ). Ventrally entirely golden-brown, with dense pile of fine hairs. Lateral margin with thin, glabrous band. Glabrous elliptical patches near spiracles on laterosternites II–VII. Aedeagus elongate, linear, with acuminate apex; ventral lobes membranous ( Fig. 7b ). Parameres symmetrical, apical lobe twice as long as wide, with stout spines along distal half of mesal margin, apex rounded, strongly arched at base <90 degrees, posterior corner right angled and hyaline ( Fig. 7c ). Proctiger short, length 0.7 width. Pygophore with elongate setae sparsely distributed over most of surface, with thick brush of elongate setae on posterior margin, anterior margin sinuate and convergent to rounded apex ( Fig. 7b ).

Macropterous female. Paratypes (n = 8), length 8.40–8.88 (mean = 8.62); maximum width 4.72–5.04 (mean = 4.90). Similar to male in general structure and coloration except as follows: Hemelytra surpassing posterior margin of tergum VII. Left laterosternite VI without spine on posterior margin. Mediosternite VII (subgenital plate) with lateral margins convergent to broadly rounded posterior margin; apex with semicircular median notch; width 1.05 length; length at midline 0.88; maximum width 0.92 ( Fig. 7e ).

Brachypterous male and female. Unknown.

Diagnostic features. Australambrysus alvarado n.sp. has no spine on the posterior margin of female left laterosternite VI ( Fig. 7e ), which differs from A. aguaro n.sp. with a short spine ( Fig. 6e ). Males of A. alvarado n.sp. can be distinguished from those of A. aguaro n.sp. ( Fig. 6d ) and A. clavieri n.sp. ( Fig. 8b ) by the more dramatically arched parameres. The pseudoparameres are unlike those of any other species in this complex for which males are known; they are subquadrate with the posterior margin straight to shallowly convex and with a small lobe ( Fig. 7d ).

Habitat description. The stream at the type locality ( Fig. 7f ) generally was slow and shallow (<1 m) with reaches of negligible flow and others with large rocks and moderate current. Australambrysus alvarado n.sp. was collected along with Limnocoris stali Montandon, 1897b at the type locality; however, A. alvarado n.sp. occurred in the marginal fine rootmats ( Fig. 7f inset), whereas L. stali was collected among rocks in the current.

Distribution. This species has been collected from streams in five provinces, all in the northern half of Colombia ( Fig. 9 ).

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

Type depository: Enns Entomology Museum, University of Missouri , Colombia, Missouri, USA .

Type material examined. HOLOTYPE ♁. COLOMBIA: Tolima: Mpio.Alvarado, Río Alvarado , N 0433.735’, W7457.038’, 417 m, 20 March 2016, R.W. Sites, rootmats, L-1928 ( UMC) . PARATYPES: same data as holotype (6♁, 5♀ UMC) . Antioquia: Mpio. Puerto Triunfo, Río Claro Reserva Natural, Río Claro , N0553.593’, W7451.345’, 671 m, 15 March 2016, R.W. Sites, rocks & rootmats in current; L-1916 (1♁ UMC) . Caldas: Mpio. Norcasia, Río La Miel , N0534.273’, W7451.543’, 237 m, 17 March 2016, R.W. Sites, marginal veg in current, L-1922 (1♀ UMC) . Cesar: Augachica, Caño Caimán , 18 August 2010, N. Torres, pond (1♀ UMC) . Choc: Mpio. Quibd, Ro Tutenendo , 3 September 2002, L. Alvarez (1♁, 1♀ UMC; 3♁, 3♀ UCO) . Tolima: Mpio. Doima, Quebrada Doima, N 0428.073’, W7455.961’, 522 m, 20 March 2016, R.W. Sites, rootmats & overhanging Papyrus, L-1929 (1♁ UMC) .

Additional material examined. COLOMBIA: Tolima: Mpio. Alvarado, Río Alvarado , N 0433.735’, W7457.038’, 417 m, 20 March 2016, R.W. Sites, rootmats, L-1928 (1♁, DNA-extraction #H6 UMC) .

Figures

FIGURE 1. Part of a Bayesian Inference dendrogram showing relationships among five species in the Australambrysus plax species complex. Complete dendrogram is available in Sites (2022).

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.