Picrops tuberculatus Sites, Rodrigues & Reynoso, 2017

Reynoso-Velasco, Daniel, 2017, New combinations, status, and species of Neotropical Ambrysini (Heteroptera: Naucoridae: Cryphocricinae), Zootaxa 4323 (4), pp. 503-518 : 512-516

Picrops tuberculatus Sites, Rodrigues & Reynoso NEW SPECIES

Figs. 19–28

Description. Macropterous female. HOLOTYPE, length 9.92; maximum width 6.28. Paratypes (n = 10), length 9.60–10.24 (mean = 9.82); maximum width 5.92–6.48 (mean = 6.20). General shape elliptical to oval; widest across embolia ( Fig. 21 ); exceptionally dorsoventrally flattened for family. Overall dorsal coloration yellowish anteriorly, wings variable from light to dark brown, extensively mottled; some specimens tinged with rose on head, pronotum, forefemora, and connexiva. Dorsal surface punctate throughout. Ventral coloration yellowish brown.

Head. Head length 1.52; maximum width 2.64. Mostly yellow with brown median markings, punctate. Eyes strongly convergent anteriorly, synthlipsis 0.84; thin band of cuticle along posterolateral margin of eye, anterolateral corner of thin band of cuticle right angled; eyes not raised above level of vertex or pronotum. Anterior margin between eyes slightly convex, not extending anteriorly in front of eyes; posterior margin between eyes strongly convex, extending posteriorly 39% of head length. Labrum width 1.65× length, evenly rounded. Labium with three visible yellowish brown segments, darkening distally, extending 0.40 beyond labrum not including extruded stylets. Antennal proportions 1:7:6:3; length 0.68; extending to near lateral margin of eye; segment 2 broad, flattened, quadrate; segments 3 and 4 elongate, slender, with long setae.

Thorax. Pronotum punctate; ground color medium yellow; major brown markings medial, mid-lateral, posterolateral, anterolateral; other smaller brown markings and punctures; transverse sulcus marking anterior border of transverse band in posterior 1/4; lateral margins convergent, evenly convex, explanate; posterior margin straight; anterior margin deeply concave between eyes to embrace convex posterior margin of head; posterolateral corner doubled, anterior corner distinctly, obtusely angled, posterior corner rounded; greatest width 8.51× length at midline; length at midline 0.62; maximum width at posterolateral corners 5.28. Prothorax ventrally yellow and pruinose throughout except white, glabrous, shining cuticle along lateral margin and extending mesad near middle; elongate setae throughout much of pruinose area; apices of propleura meeting at midline, not appressed to prosternellum. Probasisternum becoming more prominent anteromedially, culminating in darkly colored spinelike production at anterior margin. Mesoepisternum with rounded lobe over base of coxa making mesal end of pleural suture curved. Scutellum punctate; triangular; yellowish with contiguous, broad, brown, irregular suffusion on both sides of midline; width 4.0× length, width 3.40, length 0.84. Hemelytra punctate, pale to medium brown, darker mottling throughout, membrane darker and nearly concolorous, length 7.60 (chord measurement). Claval commissure 1.24. Embolium length 3.16, greatest width 1.06, lateral margin convex, pale in anterior 3/4 and brown posteriorly. Hind wings extending to anterior margin of tergum VI. Mesobasisternum flat, with sulcus on midline continuing through subtriangular mesosternellum. Metasternellum (=metaxyphus) moderately elongate, subtriangular, with lateral margins concave, apex acuminate.

Legs. All legs segments yellowish. Profemur posterior margin with row of short brown spines along basal half, anterior margin with dense pad of setae without associated spines. Protibia and tarsus with occlusal inner surface flattened and with spatulate setae; tarsus one-segmented, movable; pretarsal claw indistinct. Procoxa with cluster of stout, brown anteromedial spines. Meso- and metacoxae partially recessed into thorax. Meso- and metafemora slender, with row of elongate hairs along posterior margins; metafemur with row of short brown pegs on distal 2/3 of posteroventral margin. Mesotibia with ventrolateral, dorsolateral, and two medial rows of stout reddish-brown spines; medial rows of spines include combs of 3–5 spines; ventral surface with 4 distal comb rows of spines. Metatibia with ventrolateral, dorsolateral, ventromedial, and dorsomedial rows of single (not in combs) stout reddish-brown spines; mesal surface with profuse long, golden swimming hairs; ventral surface with 5–8 distal comb rows of spines. Metatarsus with long, golden swimming hairs. Meso- and metapretarsi with paired claws slender, gently curved, with tips dark, basal tooth absent. Leg measurements as follows: foreleg, femur 2.48, tibia 2.26, tarsus 0.40; middle leg, femur 2.52, tibia 2.24, tarsomeres 1–3, 0.14, 0.28, 0.33; hind leg, femur 3.16, tibia 3.48, tarsomeres 1–3, 0.22, 0.68, 0.52.

Abdomen. Dorsally with lateral margins of III–VI exposed, yellow, with dark brown at anterior and posterior margins giving checkered appearance ( Fig. 21 ); lateral margin finely serrate, sparse marginal row of elongate yellow setae, group of trichobothria near posterolateral corners, posterolateral corners acuminate. Posterolateral corner of II (visible ventrally) right angled and not spinose. Ventrally yellow to yellowish brown, with dense pile of fine hairs. Lateral margin with thin, glabrous band. Glabrous rounded to oval patches posterior to spiracles on laterosternites II–VI. Midventral band of elongate setae widening from mediosternite III to subgenital plate. Mediosternite VII (subgenital plate) width 1.0× length; length at midline 1.14; maximum width 1.12; lateral margins sinuate with concavity in posterior half; posterior margin straight to slightly concave; prominent hairless tubercle on midline near posterior margin ( Fig. 19 ).

Macropterous male. Paratypes (n=10), length 9.20–9.84 (mean = 9.47); maximum width 5.76–6.24 (mean = 6.01). Setation, posterolateral corners of pronotum, scutellum proportions, embolium length generally same as for holotype. Mediosternite V asymmetrically concave. Midventral band of elongate setae completely covering elongate genital operculum. Abdominal tergum VI without modification. Mediotergite VII modified with digitate lateral process on right side; process on left side variable from acuminate ( Fig. 27 ) to slightly produced ( Fig. 28 ). Medial lobes of tergum VIII (pseudoparameres) poorly developed or absent ( Fig. 26 ). Parameres asymmetrical, elongate, wrapped over phallosoma ( Figs. 22, 23, 25 ). Pygophore with elongate setae sparsely distributed over most of surface, with thick brush on conical posterior margin ( Figs. 22, 23 ). Phallosoma elongate, linear, angled on left and right sides in apical 1/4 ( Figs. 22, 23 ); ventral lobes rastrate ( Fig. 24 ).

Diagnosis and comparative notes. Both species of Picrops are easy to recognize to the generic level by their general physiognomy. They are among the most dorsoventrally flattened naucorids with among the most slender legs. These together with the peculiar angular head, pronotal shape, and mottled coloration makes this genus recognizable at a glance. Distinguishing between the species requires female specimens, as is the case with certain groups of Ambrysus (e.g., A. hybridus species group [ Reynoso-Velasco & Sites 2016b]). The female subgenital plate of P. tuberculatus has a prominent, hairless, sometimes lightly pigmented tubercle on the midline near the posterior margin ( Fig. 19 ). In addition, the lateral margins of the subgenital plate are sinuate. In contrast, P. usingeri females lack the tubercle, the lateral margins of the subgenital plate are straight and convergent ( Fig. 18 ), and the posterior margin is usually straight, although in some specimens it can be slightly notched or concave. In males, the right process of mediotergite VII was always digitate in specimens of P. tuberculatus , whereas its condition in P. usingeri was either digitate or short, wide, and truncate. The process of the left side for each species could be acuminate, produced, or rounded. Populations of each species were found to include male specimens with more than one condition of mediotergite VII. We also found variation in male genitalia in the shapes of the pygophore and parameres; however, the variation was not consistent geographically and multiple conditions were present within populations. As such, we considered the male characteristics to be intraspecifically variable and not taxonomically reliable; males must be identified by association with contemporaneously collected females.

Habitat description. The habitat of this species is very similar to that of Picrops usingeri : leafpacks in relatively small, shallow, slowly-moving, sandy-bottomed streams running through moist tropical forest ( Fig. 29 ). Adults and nymphs can be found among masses of intact, dead leaves floating on the surface. We collected P. tuberculatus syntopically with Ambrysus stali La Rivers and A. partridgei De Carlo at or adjacent to the type locality.

Discussion. The only known congener, Picrops usingeri , occurs widely throughout much of the Amazon Basin and Guiana Shield, whereas P. tuberculatus n. sp. apparently is restricted to the Guiana Shield. Distribution patterns such as this with a widespread species and congeners with restricted ranges are common in other groups of aquatic Heteroptera.

Etymology. The species is named for the median tubercle on the female subgenital plate.

Repositories. The holotype is deposited in the Muséum National d'Histoire Naturelle—Paris (MNHN). Paratypes will be deposited in the University of Missouri (UMC), University of Kansas (SEMC), University of California—Berkeley (EMEC) and the United States National Museum of Natural History (USNM).

Type material examined. (Holotype ♀, MNHN): FRENCH GUIANA: ca . 6.5 km ESE of Saül, Crique Nouvelle France, N03°36'22.7", W53°10'34.2", 221 m, 8 November 2016, R.W. Sites, leaf packs, L-1953. Paratypes: same data as holotype (1♂, 1♀ SEMC; 2♂, 3♀ UMC); ca . 6.5 km ESE of Saül, Crique Nouvelle France, N03°35 49.8", W53°10'40.4", 200 m, 9 November 2016, R.W. Sites, leaf packs, L-1955 (3♀, 1-3rd instar, 2-4th instars UMC); ca . 8 km NNW of Saül, Crique a l'Est , N03°39'46.04", W53°13'24.78", 156 m, 10 November 2016, R.W. Sites, gravel riffles & veg margins, L-1956 (2♂, 1♀ UMC); Crique Nouvelle France @ confl. with Crique Popote / 8 November 2016, D. Post (1♀ UMC); Crique Gregoire, below upper waterfall / N5.09192, W53.07203, elev 27 m, 27 October 2016, D. Post (1♀ UMC); unnamed trib to Sinnimary R., below Takari-Tanté, carbet Takari / N4.62085, W52.92808, elev 39 m, 4 November 2016, D. Post (1♂, 1♀ USNM; 1♂, 1♀ EMEC; 4♂, 3♀, 1-4th instar UMC).

Other material examined. BRAZIL: Amazonas, Barcelos, Serra do Aracá , afluente do Igarapé da Cobra , B06, PT 769, folhiço de fundo, 00°52'13.2"N, 63°27'13.4"W, A.P.M. Santos col. (1♂, 1♀ MZUSP) ; Amazonas, Barcelos, Serra do Aracá, base, #B08, Igarapé da Cobra , montante, 00°52’34.2”N, 63°27’03.6”W, 02.VIII.2009 (1♀ MZUSP) ; Amazonas, Manaus, Reserva Ducke, Igarapé Acará , 01.VIII.1985, 2323, E. Binda & L. Aquino col. (1♂, 1♀ MZUSP, 2♀ INPA) ; Amazonas, Manaus, Reserva Ducke, Igarapé Barro Branco , 20.III.1984, 2 423, U. Barbosa col. (1♀ MZUSP) ; Pará, 1772, Rio Mapuera, Cachoeira do Engano , 15.VI.1986, V. Py-Daniel & U. Barbosa col. (1♀ MZUSP). GUYANA: Region 6, Upper Berbice, Basecamp 2, bathing creek (upstream of camp), 4°45'18.0606", -58°0'24.2382", 49 m , 30 Sep 2014, Short, Salisbury, La Cruz, stream margins, GY14-0930-01A (1♂, 1♀ UMC); Region 8, Upper Potaro Camp (c. 7 km NW Chenapau), Ridge Trail, 5°0'43.8006", - 59°38'57.9042", 585 m , 11 Mar 2014, Short, Baca, Salisbury, small marshy detrital stream, GY14-0311-02A (1♂, 1♀ UMC); Region 9, Parabara, elev 274 m, 2°6'29.52", -59°13'39.183, 3 November 2013, Short, Isaacs, Salisbury / GY 13-1103-02 A, small flowing creek with sand/detritus margins & leaf packs/stick jams (2♂, 3♀ UMC). SURINAME: Sipaliwini, Raleighvallen Nature Reserve, Voltzberg Station , N4.681833, W56.185635, 78 m, 29 July 2012, Short, Maier, McIntosh, Kadosoe, SR 12-0729-02A, stream margin (2♂, 1♀ UMC) ; Sipaliwini, Kutari River , 2°10'31.2594", -56°47'14.6364", 228 m, 20 August 2010, SR10-0820-01A, Short & Kadosoe, forest stream (3♂, 3♀, 1-1 st instar , 1-2nd instar, 1-4th instar, 1-5th instar UMC) ; Dutch Guiana, IV.17. 1944, D. C. Geiskcs / Republiek Coropina Creek / Ambrysus usingeri La Rivers Allotype ♀ (1♀ SEMC) ; Museum Leiden , Suriname exp., 1948-1949, Republiek—Zanderij, kreekie bij km 43, spoorbaan, 4-IX-1948 (2♂, 1♀ EMEC) . VENEZUELA: Amazonas, small stream 1 km N of Alto Mavaca base camp, 2°1'30"N, 65°7'0"W, 228 m., 22°C, 4 Feb 1989, CL 8006, DA Polhemus (1♂, 1♀ USNM) .

Figures

FIGURE 29. Crique Nouvelle France in French Guiana, the type locality of Picrops tuberculatus n. sp. with leaf pack habitat inset.

FIGURES 18 – 20. (18) Terminal abdominal sterna of topotypic female paratype of Picrops usingeri, (19) terminal abdominal sterna of female paratype of Picrops tuberculatus n. sp., (yellow arrow indicates tubercle on subgenital plate), (20) distribution records of species of Picrops.

FIGURES 21 – 28. Picrops tuberculatus n. sp. (21) Dorsal habitus, (22) male genital capsule, (23) male genital capsule with terga IX and X (proctiger) removed, (24) ventral surface of phallosoma, (25) dorsal surface of left and right parameres, (26) abdominal tergum VIII of male, (27) terminal abdominal terga of male paratype showing mediotergite VII (yellow arrow indicates acuminate lateral process on left side), (28) terminal abdominal terga of male paratype showing mediotergite VII with rounded lateral production on left side.