Maculambrysus transversus 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 : 216-219

Maculambrysus transversus Rodrigues, Canejo & Sites NEW SPECIES urn:lsid:zoobank.org:act:B571D410-C3E9-4D07-B068-4EAB71457E67

( Figs. 9 , 10 , 13 )

Description. Macropterous female. HOLOTYPE, length 8.90; maximum width 5.49. Paratypes (n = 12), length 7.15–10.00 (mean = 9.04); maximum width 4.48–6.10 (mean = 5.53). General shape fusiform; widest across embolia, sometimes across abdominal segment III. Overall dorsal coloration anteriorly yellow with dark-brown pattern on forelegs, head, and pronotum; posteriorly with dark to dark-brown scutellum and hemelytra. Exposed abdominal terga with alternating yellow and dark-brown checkered appearance. Dorsal surface coarsely punctate ( Fig. 9A ). Ventrally, mostly brown, with dark-brown areas on propleuron and metapleuron ( Fig. 9B ).

Head. Head length 1.40; maximum width 2.20. Eyes convergent, synthlipsis 0.85; thin band of cuticle posterior to eye; eyes flat and not raised above level of vertex, slightly raised above level of pronotum. Anterior margin between eyes convex, extending anteriorly in front of eyes 6.5% of head length; posterior margin between eyes strongly convex, extending posteriorly 29% of head length. Labrum width 1.5 × length, evenly rounded. Labium brown, with three visible segments, extending 0.40 beyond labrum. Antennal segment proportions 8:34:42:15, length 0.59, elongate hairs on segment 4 and distal 2/3 of 3.

Thorax. Pronotum mostly yellowish-brown with dark-brown punctures, anteromedial brown maculation, irregular longitudinal brown stripes, some longitudinal stripes enhanced with dark punctures; slightly rugose; lateral margins convex; sparse erect setae; strongly convergent anteriorly; posterior margin nearly straight; anterior margin deeply concave receiving convex posterior margin of head; transverse line of punctures defining anterior margin of band in posterior 1/4; posterolateral corners obtuse, rounded; width 3.03× length; length at midline 1.45; maximum width at posterolateral corners 4.40. Prothorax ventrally brown and lightly pruinose medially, with yellow glabrous lateral band; apices of propleura meeting broadly at midline, separated from level of prosternellum. Probasisternum brown, with sharp medial carina and generally appearing pruinose, row of elongate golden hairs lateral to carina. Prosternellum light-brown, extending beneath apices of propleura; apices of propleura meeting broadly at midline, separated from level of prosternellum. Elongate golden setae along posterior margin of propleuron. Scutellum mostly brown with yellow anterior corners and apex, triangular, densely punctate, width 1.93× length, width 2.90, length 1.50. Hemelytra densely punctate. Claval commissure length 1.10. Embolium length 2.70, greatest width 0.79; lateral margin slightly convex in proximal half, more pronounced in distal half. Hind wings well-developed. Mesobasisternum with midventral longitudinal tumescence with sulcus on midline; tumescence terminating posteriorly as acute mesosternellum. Metasternellum (=metaxyphus) subtriangular, with apex acute.

Legs. All leg segments yellowish-brown, darker distally on foreleg. Profemur yellowish-brown with dark-brown laterally, near junction with tibia, and posteriorly; dark-brown posterior marking not extending anteriorly; row of 7–9 combs of short brown spines in basal half of posterior margin; anterior margin with dense pad of setae without associated spines. Protibia and -tarsus with inner surface flattened and with spatulate setae; tarsus immovable, one- segmented; pretarsal claw single, minute, triangular. Procoxa with dark-brown basal marking on lateral to anterior surfaces, cluster of stout brown anteromedial spines. Mesocoxa partially recessed into thorax. Metacoxa with longitudinal sulcus that can accommodate flexed metafemur. Meso- and metafemora with rows of short, brown spines on anterior margins; spines restricted to basal 1/3, combs of 1–4 spines irregularly spaced along full length of metafemur. Mesotibia with ventrolateral, ventromedial, dorsolateral, and dorsomedial rows of stout reddish-brown spines, dorsolateral and dorsomedial rows include combs of up to four spines; stout spines at apical rim dorsally, two transverse rows of stout spines at apex of ventral margin. Metatibia with ventrolateral, ventromedial, dorsolateral, and dorsomedial rows of stout reddish-brown spines, transverse rows of stout spines at apex of ventral margin. Meso- and metatibiae and -tarsi with long, pale swimming hairs; hairs sparse on mesotibia and -tarsus, profuse on metatibia and -tarsus. Meso- and metapretarsi with paired claws slender, curved in distal half, with basal tooth. Leg measurements as follows: foreleg, femur 2.05, tibia 1.50, tarsus 0.40; middle leg, femur 2.12, tibia 1.81, tarsomeres 1–3, 0.09, 0.30, 0.35; hind leg, femur 2.58, tibia 2.95, tarsomeres 1– 3, 0.15, 0.45, 0.50.

Abdomen. Dorsally with lateral margins of III–V exposed; lateral margin smooth, with row of pale setae, group of trichobothria on dorsal surface near posterolateral corners. Posterolateral corners of II–III right angled to rounded, IV–VI spinose. Ventrally mostly brown medially, brownish-yellow laterally, with pile of fine hairs. Lateral margin with thin glabrous band. Glabrous patches on laterosternites II–VII. Mediosternite VI without spines or projections on posterior margin, posterolateral corner slightly swollen. Mediosternite VII (subgenital plate) with a small, acute projection at posterolateral corner, slightly convex medially ( Fig. 9J ); subgenital plate width 1.31× length; length at midline 0.80; maximum width 1.05

Macropterous male. Paratypes (n = 12), length 7.67–9.02 (mean = 8.67); maximum width 4.42–5.70 (mean = 5.30). Similar to female in general structure and coloration, except as follows: Mediosternite V with posterior margin asymmetrical. Accessory genitalic process of abdominal tergum VI narrow, angled to right, posterior margin rounded, not reaching posterior margin of tergum VII ( Fig. 9C ). Medial lobes of abdominal tergum VIII (pseudoparameres) with medial margin oblique and shallowly convex, posteromedial corner rounded, without notch at posterolateral corner ( Fig. 9D ). Phallosoma elongate, convergent in distal third, with acuminate apex; left ventral lobe reflexed dorsad, lightly sclerotized, transverse, without spines or teeth ( Figs. 9G–H ). Proctiger with lateral margins slightly convergent to a rounded posterior margin ( Fig. 9E ). Parameres symmetrical, curved anterodorsally, with apex rounded, elongate setae originating on posterior half, extending mesad ( Fig. 9I ). Pygophore with elongate setae sparsely distributed over most of surface, with thick brush of elongate setae on posterior margin; anterior margin shallowly acuminate ( Figs. 9E–F ).

Comparative notes. This new species can be distinguished from congeners by the relatively shorter accessory genitalic process of male abdominal tergum VI, which does not reach the posterior margin of segment VII ( Fig. 9C ), whereas in the other species where this structure has been illustrated, this process is distinctly larger and reaches or exceeds the posterior margin of segment VII (as in Fig. 8C ). The female subgenital plate is also a diagnostic feature, since the posterior margin of the plate does not exceed the limit of the posterolateral angle of abdominal tergum VI, in addition to having a small, acute projection at the posterolateral corner of the plate ( Fig. 9J ).

In the other species of Maculambrysus , except M. obscuratus and M. stali , the posterior margin of the subgenital plate reaches or exceeds the posterolateral corner of tergum VI. Given the size of the subgenital plate in M. transversus n. sp. and the absence of tubercle or spines in the posteromedial corner of left laterosternite VI, we consider the new species morphologically similar to M. stali , although these species are distinguished by the shape of the accessory genitalic process, the left ventral lobe of the phallosoma and the lateral margin of the subgenital plate.

Etymology. The specific epithet transversus , from Latin (= transverse), is in reference to the transversely oriented left ventral lobe of the phallosoma.

Distribution and habitat. This species is distributed from the southern Amazon, in the state of Pará, to the coastal region of northeastern Brazil, in the states of Alagoas and Rio Grande do Norte ( Fig. 13 ). Specimens from Alagoas were mostly collected in rootmats on the banks of streams ( Figs.10A–B ), and sometimes associated with gravel and sand substrate. Some specimens were collected in sandy streams, in deforested areas, also associated with the banks ( Fig. 10C ). In Rio Grande do Norte, specimens were collected among marginal emergent vegetation ( Fig. 10D ).

Type material examined. HOLOTYPE ♀ ( MZUSP), BRAZIL, Alagoas, Penedo, jusante da represa, Dique da PAISA , 10°17’39”S, 36°30’39”W, 10 m, 16.ix.2017, L-0002, H. Rodrigues col. PARATYPES: same data as holotype (15♂, 6♀ MZUSP; 2♂, 2♀ INPA; 2♂, 2♀ UMC) . Alagoas: Penedo , 10°15’10”S, 36°32’48”W, 40 m, 17.IX.2017, L-0004, H. Rodrigues col. (4♂, 5♀ MZUSP) ; Murici, 09°16’37”S, 35°57’35”W, 124 m, 25.ix.2017, L-0013, H. Rodrigues & K. Paresque col. (1♀ CEIOC) ; Quebrangulo, REBIO Pedra Talhada ( REBIO pt6), 9°14.041’S, 36°26.931’W, 05.VIII.2018, C.F.B. Floriano, J.M.S. Rodrigues & J.F. Barbosa col.(8♂, 7♀ CEIOC) ; Viçosa, Fazenda Baixa Funda , 9°19’27”S, 36°16’59”W, 280 m, 21.III.2019, H. Rodrigues col. (2♂, 2♀ MZUSP) ; same data, except: 30.XI.2021 (2♂, 2♀ MZUSP) . Rio Grande do Norte: Natal, Rio Pitimbu, Ponte no final da Av. Ayrton Senna , 5°55’00.7”S, 35°11’54.0”W, 03.xii.2019, UFRN-CENT 905, 1538, R.P.R.Canejo col. (2♂ CEAAVF) ; same data, except 17.viii.2019, UFRN-CENT 1539 (1♂ CEAAVF) ; Natal, Rio Pitimbu , BR-101, 5°52’48.1”S 35°13’32.6”W, 22.xii.2019, UFRN-CENT 1540, R.P.R.Canejo col. (1♀ CEAAVF) ; Extremoz, Rio Doce, Divisa Natal / Extremoz , 5°43’09.5”S 35°13’59.5”W, 11.i.2020, UFRN-CENT 906, R.P.R.Canejo col. (1♀ CEAAVF) . Pará: Tailândia, Igarapé em plantação de Dendê , -2.60391, -48.73913, 29.XI.2012, E.J. Cunha col. (4♂, 2♀ CEIOC) .

Additional material examined. BRAZIL, Pará: Novo Progresso , alagado em estrada de terra perpendicular à BR-163, 04.VIII.2015, 9°28’09”S, 54°39’10”W, F. Dagosta, M.M.F. Marinho, P. Camelier & V. Giovannetti col. (1♂ CEIOC) .

Figures

FIGURE 8. Maculambrysus obscuratus (Montandon, 1898) n. comb., (A) dorsal and (B) ventral habitus of female from Pará, Brazil (CEIOC), (C) 6th and 7th abdominal terga of male, (D) 8th abdominal tergum of male, (E) genital capsule of male, (F) genital capsule with proctiger removed, (G) ventral surface of phallosoma, arrow indicates left endosomal lobe, (H) parameres, (I) terminal abdominal sterna of female (setae have been removed to reveal shape), arrow indicates small spine of posteromedial corner of left laterosternite VI. Size bars = 1 mm and applies only to Figs. A–B.

FIGURE 9. Maculambrysus transversus n. sp., (A) dorsal and (B) ventral habitus of female paratype from Alagoas, Brazil (CEIOC), (C) 6th and 7th abdominal terga of male, (D) 8th abdominal tergum of male, (E) genital capsule of male, (F) genital capsule with proctiger removed, (G) ventral surface and (H) right side of phallosoma, black arrows indicate left endosomal lobe, (I) parameres, (J) terminal abdominal sterna of female (setae have been removed to reveal shape). Size bars = 1 mm and applies only to Figs. A–B.

FIGURE 10. Collecting localities of Maculambrysus transversus n. sp., (A–B) type locality, downstream of Dique da PAISA, Penedo, Alagoas, Brazil (A) general habitat, (B) specific habitat, rootmats in a shaded bank, (C) Penedo, bank of a sandy stream in a deforested area, (D) Natal, Rio Grande do Norte, bank of Pitimbu River, emergent vegetation.

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.