Australambrysus tuberculatus Rodrigues, Canejo & Sites, 2024

Rodrigues, Higor D. D., Canejo, Rafael P. R. & Sites, Robert W., 2024, New species, new combinations, and morphological notes of South American Ambrysinae (Heteroptera: Naucoridae), Zootaxa 5447 (2), pp. 199-224 : 201-206

Australambrysus tuberculatus Rodrigues, Canejo & Sites NEW SPECIES urn:lsid:zoobank.org:act:149DEF5A-2FB3-4B9A-B839-7B061CCF330B

( Figs. 3 , 13 )

Description. Macropterous male. HOLOTYPE, length 8.80; maximum width 5.12. Paratypes (n = 7), length 8.13–9.45 (mean = 8.80); maximum width 4.78–5.36 (mean = 5.05). General shape ovate, broadly convex laterally; widest across embolia. Overall dorsal coloration brown, head; pronotum, part of embolium and abdominal terga lighter ( Fig. 3A ). Dorsal surface coarsely punctate. Ventrally, brownish ( Fig. 3B ).

Head. Length 1.44; maximum width 1.92. Brown, with wide dark-brown median area narrowing anteriorly, coarsely punctate. Eyes flat and not raised above level of vertex or pronotum, convergent anteriorly, synthlipsis 0.80. Anterior margin between eyes slightly convex, nearly straight, extending anteriorly in front of eyes 8.33% of head length; posterior margin between eyes strongly convex, extending posteriorly 33.33% of head length. Labrum width 2.30× length, evenly rounded. Labium with three visible segments, basal two segments brown, distal segment dark-brown, extending 0.48 beyond labrum. Antennal proportions 6:14:20:16, length 0.56, elongate hairs on segment IV and posterior half of III.

Thorax. Pronotum coarsely punctate; transverse sulcus marking anterior border of transverse band in posterior 1/4; brown with yellowish marks on lateral margins, midline, and transverse band; lateral margins convex, with row of short recumbent setae, convergent anteriorly; posterior margin shallowly convex in middle, slightly lobed laterally; anterior margin deeply concave to embrace convex posterior margin of head and eyes; posterolateral corners slightly truncate ( Fig. 3A ); width 2.78× length; length at midline 1.52; maximum width at posterolateral corners 4.24. Ventrally, prothorax with narrow glabrous band along lateral margin; apices of propleura meeting broadly at midline, in same level of prosternellum; propleuron brown on inner half and yellowish laterally, and 2/3 of posterior margin with elongate golden setae. Probasisternum brown, with sharp median carina in anterior half and with row of setae lateral to carina. Scutellum coarsely punctate, triangular, entirely brown with lateral margins slightly lighter, width 2.05× length, width 2.96, length 1.44. Hemelytra densely punctate. Clavus with yellowish transverse stripe at base; claval commissure yellowish, length 0.88. Embolium length 2.56, greatest width 0.56; lateral margin straight in anterior 3/4, slightly convex posteriorly, yellow-brown in anterior 2/3, becoming darker posteriorly. Oblique suture connecting claval and embolar sutures near bases. Hind wings well-developed. Mesobasisternum with midventral longitudinal tumescence with sulcus on midline through triangular mesosternellum; tumescence with row of golden setae. Mesopleuron with rows of golden setae along lateral and posterior margins. Metasternellum (= metaxyphus) subtriangular with apex acute.

Legs. All leg segments light-brown, except yellowish tarsomeres. Profemur dorsally coarsely punctate; posterior margin with brush of elongate setae in basal 1/4; anterior margin with dense pad of setae. Protibia and tarsus with occlusal surface flattened and with spatulate setae; tarsus immovable, one-segmented; pretarsal claw single, minute, triangular. Procoxa with cluster of stout, brown anteromedial spines. Meso- and metacoxae partially recessed into thorax, with broad longitudinal sulcus that can accommodate flexed femora. Meso- and metafemora with row of short, brown spines on anterior margin; spines restricted to basal half on mesofemur, nearly full-length of metafemur. Meso- and metatibiae with ventrolateral, ventromedial, dorsolateral, and dorsomedial rows of stout reddish-brown spines; meso- and metatibiae with one comb row of reddish-brown spines at apical rim dorsolaterally, and two comb rows at apical rim ventrally. Meso- and metatibiae and -tarsi with long pale swimming hairs; hairs profuse on metatibia and -tarsus. Meso- and metapretarsi with paired claws slender, curved, without basal tooth. Leg measurements as follows: fore leg, femur 2.44, tibia 2.04, tarsus 0.36; middle leg, femur 2.24, tibia 2.08, tarsomeres 1–3, 0.10, 0.26, 0.40; hind leg, femur 2.60, tibia 3.08, tarsomeres 1–3, 0.20, 0.50, 0.50.

Abdomen. Dorsally with lateral margins of III–VIII exposed, each margin brown anteriorly and light-brown posteriorly; 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 narrowly rounded to right angled and not spinose, IV–VII forming spines. Accessory genitalic process of tergum VI absent ( Fig. 3D ). Medial lobes of VIII (pseudoparameres) with posteromedial corner acutely rounded, posterior margin distinctly concave; lateral lobes of VIII with lateral margins shallowly concave in posterior half ( Fig. 3E ). Ventrally entirely golden-brown, with dense pile of fine hairs, except two median glabrous stripes on mediosternites IV–V ( Fig. 3B ). Lateral margin with thin, glabrous band. Glabrous elliptical patches near spiracles on laterosternites II–VII. Mediosternite III with midventral ridge; V near posterior margin on right side with a distinct protuberance extending ventrally ( Figs. 3B–C ). Proctiger short, length 0.73× 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 ( Figs. 3F–G ). Phallosoma elongate, almost linear, with acuminate apex; ventral lobes membranous ( Fig. 3H ). Parameres asymmetrical, with left paramere arched at base 90 degrees, right paramere arched> 90 degrees, elongate setae along posteromesal margin, apex rounded.

Macropterous female. Paratypes (n = 8), length 8.02–8.94 (mean = 8.40); maximum width 4.90–5.21 (mean = 5.04). Similar to male in general structure and coloration, except as follows: Posterior margin of left and right laterosternites VI without spine. Mediosternite VII (subgenital plate) with lateral margins converging to broadly rounded posterior margin; apex with semicircular median notch; subgenital plate width 1.13× length; length at midline 0.92–0.97; maximum width 1.03–1.06. Laterosternite VII with mesal margin shallowly convex; posterolateral corner spinose, extending posteriorly further than apex of subgenital plate ( Fig. 3J ).

Comparative notes. Males of Australambrysus tuberculatus n. sp. are easily distinguished from their congeners by the presence of a distinct protuberance on abdominal sternum V ( Figs. 3B–C ), which is absent in all other species of Ambrysinae . Females can also be easily distinguished from other species in the A. plax complex by abdominal laterosternite VII distinctly spinose and extending posteriorly further than the apex of the subgenital plate ( Fig. 3I ). Australambrysus tuberculatus n. sp. was represented in the dendrograms by Sites (2022, 2023a) as Ambrysus sp. 2 and Australambrysus sp. , respectively. As such, A. tuberculatus n. sp. is sister to A. aguaro Sites, 2023 , which is known from Venezuela.

Habitat description. The material from Minas Gerais was collected in two different environments. The specimens from the Parque Nacional da Serra do Cipó were collected in a stream approximately one-meter-wide, shaded, and with a gravel substrate. The specimen from the municipality of Luz was collected on the bank of a muddy stream without marginal vegetation.

Distribution. This species is distributed from the Amazon, in the states of Roraima and Rondônia in northern Brazil, to the Cerrado, in the states of São Paulo and Minas Gerais in southeastern Brazil ( Fig. 13 ).

Etymology. The specific epithet tuber, from Latin (= tubercle, protuberant), refers to the distinct protuberance on the male abdominal sternum V, a unique feature among Ambrysinae .

Type material examined. All specimens macropterous. HOLOTYPE ♂ ( MZUSP), BRAZIL, São Paulo, Pedregulho, 15.IX.1989, C.G. Froehlich col. PARATYPES: BRAZIL, Roraima: 436, Rio Urarica-á, Igarapé Canoã , 02.IX.1987, V. Py-Daniel & U. Barbosa col. (1♂, 1♀ INPA) ; 1338, BR-421 , Igarapé Boa Vista , 31.VII.1985, V. Py-Daniel & L. Aquino col. (1♂, 1♀ INPA) . Rondônia: 1690, Rio Preto , 19.VIII.1985, V. Py-Daniel & U. Barbosa col. (1♂, 2♀ MZUSP) ; 224, Bacia do Rio Candeias, Igarapé 13: 20, 05.VIII.1985, V. Py-Daniel & U. Barbosa col. (1♂, 1♀ MZUSP; 2♂, 3♀ UMC) ; 36, Bacia do Rio Jaciparaná, Igarapé Vertente ( Barracão ), 19.VIII.1985, V. Py-Daniel & L. Aquino col. (1♂, 1♀ MZUSP; 1♂, 1♀ CEIOC) ; Minas Gerais: Parque Nacional da Serra do Cipó, córrego at trail to Canyon das Bandeirinhas , 19°24’21.0”S, 43°34’44.7”W, 815 m, 06.VI.2014, H. Rodrigues col. (2♂ MZUSP) .

Additional material examined. BRAZIL: Minas Gerais, Ribeirão Jorge Grande , 19º40.252'S, 45º36.635'W, 623 m, 28 Nov. 2016, L-1972, R.W. Sites coll. (1♀ DNA-extraction #H18 UMC) .

Figures

FIGURE 3. Australambrysus tuberculatus n. sp., (A) dorsal, (B) ventral and (C) lateral habitus of male holotype (MZUSP), arrows indicate protuberance of abdominal sternum V, (D) 6th and 7th abdominal terga of male, (E) 8th abdominal tergum of male, (F) genital capsule of male, (G) genital capsule with proctiger removed, (H) ventral surface of phallosoma, (I) terminal abdominal sterna of female, arrows indicate small digitate process on posterior margin of laterosternite VI. Size bars = 1 mm and applies only to Figs. A–B. lsVII = laterosternite VII, sgp = subgenital plate.

FIGURE 13. Distribution records for South American species of Ambrysinae (Naucoridae). Imprecise localities (e.g., only the state is known) are displayed as question marks.