Ambrysus sitesi Reynoso, 2019

Reynoso-Velasco, Daniel & Sites, Robert W., 2019, Descriptions of four new species of the Ambrysus signoreti Stål species complex (Heteroptera: Nepomorpha: Naucoridae), Zootaxa 4615 (2), pp. 285-302 : 298-301

Ambrysus sitesi Reynoso NEW SPECIES

( Figs. 3 , 8–9 )

Description. Macropterous female. HOLOTYPE, length 11.87; maximum width 7.25. Paratypes (n = 10), length 10.70–11.60 (mean = 11.31); maximum width 6.80–7.50 (mean = 7.17). General shape ovate; widest across embolia ( Fig. 8A ). Overall dorsal coloration of hemelytra brown to dark brown with yellowish brown marks; head and pronotum light brown with dark brown marks; legs yellowish brown. Dorsal surface coarsely punctate. Ventral coloration of head and thorax yellowish, abdomen with yellowish pubescence.

Head. Head length 1.60; maximum width 3.20. Mostly light brown with dark brown marks along midline and posteriorly; coarsely punctate. Eyes convergent anteriorly, synthlipsis 1.48; 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 7.8% of head length; posterior margin between eyes strongly convex, extending posteriorly 29.7% of head length. Labrum width 1.7× length, evenly rounded. Labium with three visible yellowish brown segments, darkening distally, extending 0.49 beyond labrum not including extruded stylets. Antennal proportions 3:14:22:9, length 0.72, extending to lateral margin of eye, elongate hairs on segment 4 and distal half of 3.

Thorax. Pronotum coarsely punctate, ground color medium brown, profuse dark brown markings, dark brown longitudinal line behind eye; transverse sulcus marking anterior border of transverse band in posterior 1/3; transverse band light brown anteriorly, brown posteriorly; lateral margins yellowish brown, convergent, evenly convex, explanate; posterior margin almost straight; anterior margin deeply concave between eyes to embrace convex posterior margin of head; posterolateral corners rounded; width 2.7× length; length at midline 2.28; maximum width at posterolateral corners 6.26. Prothorax ventrally pruinose throughout, except laterally; apices of propleura meeting at midline, not appressed to prosternellum; propleuron yellowish, light brown posteriorly, medial 2/3 of posterior margin with golden setae. Probasisternum with sharp median carina and row of setae lateral to carina. Prosternellum not covered by apices of propleura. Scutellum coarsely punctate, triangular, dark brown, light brown coloration at anterior corners and along midline, width 2.1× length, width 4.32, length 2.00. Hemelytra densely punctate, brown to dark brown, length 8.12 (chord measurement); corium dark brown, yellowish brown ovate and yellowish commashaped marks at lateral and posterior margins, respectively. Clavus dark brown in lateral half, brown in mesal half with dark brown close to base and apex, length 3.8× width, length 4.56, width 1.20; claval commissure dark brown, length 1.30. Embolium length 3.32, greatest width 1.05; lateral margin convex, yellowish in anterior 2/3, brown posteriorly. Membrane dark brown ( Fig. 8A ). Hindwings extending to middle of tergum VII. Mesobasisternum tumescence negligible, with sulcus on midline continuing through triangular mesosternellum. Metasternellum (= metaxyphus) transverse, subtriangular, with median carina.

Legs. All leg segments yellowish brown. Profemur yellowish brown; posterior margin with row of tightly arranged setae in basal 2/3, row of short brown spines along middle third; anterior margin with dense pad of setae without associated spines. Protibia and -tarsus with occlusal inner 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. Meso- and metafemora with row of short, light brown spines on anterior margin; spines restricted to basal half on mesofemur, nearly full length of metafemur. Mesotibia with ventrolateral and dorsolateral rows of stout reddish-brown spines; mesolateral rows intermixed with combs of two to six spines. Metatibia with ventrolateral and dorsolateral rows of stout reddish-brown spines. Meso- and metatibiae with semi-circlet of spines at apices on dorsal and mesal margins; two comb rows of stout spines near apex of ventral margin. Meso- and metatibiae and metatarsus with long, yellow swimming hairs; 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 2.60, tibia 2.02, tarsus 0.47; middle leg, femur 2.55, tibia 2.30, tarsomeres 1–3, 0.22, 0.49, 0.52; hind leg, femur 3.34, tibia 3.72, tarsomeres 1–3, 0.28, 0.88, 0.67.

Abdomen. Dorsally with lateral margins of III–VI exposed, each brown in anterior 1/3 and light brown posteriorly; lateral margins of II to basal half of III smooth and distal half of III to VI finely serrate, marginal row of profuse and short yellow setae, group of trichobothria near posterolateral corners. Posterolateral corner of II (visible ventrally) narrowly rounded, right angled, III–VII acute. Ventrally yellowish, with dense pile of fine hairs. Lateral margin with thin, glabrous band. Glabrous rounded to oval patches near spiracles on laterosternites II–VI. Mediosternite VII (subgenital plate) asymmetrical, width 1.1× length; length at midline 1.24; maximum width 1.38; lateral lobe at mid-length of left margin broadly rounded; posterolateral corners pointed; wide central lobe produced posteriorly slightly further than posterolateral corners ( Fig. 8B ).

Macropterous male. Paratypes (n = 10), length 9.80–11.00 (mean = 10.52); maximum width 6.20–7.00 (mean = 6.62). Coloration, setation, pronotum proportions, posterolateral corners of pronotum, scutellum proportions, embolium length generally same as for holotype. Otherwise hindwings extending to posterior margin of tergum V. Accessory genitalic process of tergum VI slender, gently curved to right close to the base, widening distally, apex pointed ( Fig. 8C ). Medial lobes of tergum VIII (pseudoparameres) symmetrical, posterolaterally produced, posterolateral corner narrowly rounded, extending posteriorly further than posteromesal corner ( Fig. 8D ). Phallosoma elongate, linear, slender, slightly constricted basally; left endosomal sclerite reduced, with small and inconspicuous denticles; right endosomal sclerite absent ( Fig. 8E ). Parameres symmetrical, almost as long as maximum width, mesal margin rounded, setae emanating from distal 1/3 of dorsal surface. Proctiger slightly shorter than width at base. Pygophore with elongate setae sparsely distributed over most of surface, with thick brush of elongate setae on posterior margin ( Fig. 8F ).

Discussion. The conspicuous dorsal pigmentation of specimens of A. sitesi is similar to that of A. lunatus Usinger and A. signoreti Stål. The morphology of the endosomal sclerites of the males suggests that this species could be closely related to A. lundbladi Usinger. In his work on the Ambrysus of Mexico, La Rivers (1953) described the subspecies A. lunatus menoides from the central state of Puebla. He cited paratype specimens from the state of Chiapas (Ixtapa) that were deposited in the UMMZ. We examined a female paratype that was deposited in the CAS and found that the morphology of the SGP was different to that reported for the subspecies. Instead, the morphology corresponded to the herein described A. sitesi . Based on this and our extensive collecting in the area, we consider the subspecies A. l. menoides not to be distributed in the state of Chiapas.

Diagnostic features and comparative notes. Females of this species exhibit a characteristic SGP with a broadly rounded lateral lobe at mid-length of the left margin. Other species in the A. signoreti complex present a lateral lobe on the left margin of the SGP (sometimes also on the right margin), but in general the lobe is low and pointed (e.g., A. colimanus , A. lunatus ). The species A. scalenus presents a similar left-lobed margin of the SGP (examined on the allotype in the SEMC); however, the lobe extends further laterally and appears truncate. Males of A. sitesi present the phallosoma with no right endosomal sclerite and a reduced left endosomal sclerite with inconspicuous rounded denticles along the mesal margin. To our knowledge, the rare A. lundbladi is the only other species from this species complex that exhibits the phallosoma with an absent right endosomal sclerite and the left sclerite reduced.

Habitat description. The type locality at Río Rana (L-1906), close to the town of San Gabriel Mixtepec, is in the south central area of the Mexican state of Oaxaca, on the Sierra Madre del Sur mountain range, at an elevation of 712 meters. At the type locality the stream is 5–10 meters wide, with fast current, and boulders and cobble ( Fig. 9 ). Specimens were collected by disturbing the substratum with the net along the stream margin.

Distribution. Ambrysus sitesi is distributed in the highlands of the Mexican states of Chiapas and Oaxaca and the western area of Guatemala, in the Huehuetenango Department ( Fig. 3 ). The records from Oaxaca are in the area of the Sierra Madre del Sur biogeographic province, while those from Chiapas and Huehuetenango are in the Chiapas biogeographic province. One record from Chiapas (L-1899) is in the Mexican Pacific Coast biogeographic province. This species was collected syntopically with various congeners, including A. circumcinctus (L-1339, L- 1341, L-1350, L1884, L1897), A. circumcinctus and A. pudicus (L-1881, L-1898), A. circumcinctus and A. spicatus (L-1349), A. circumcinctus , A. parviceps , and A. pudicus (L-1899); A. chiapanecus Reynoso, Sites & Novelo (L- 1340, L-1886); A. chiapanecus and A. spicatus (L-1885); A. mexicanus Montandon , A. pygmaeus La Rivers , and A. spicatus (L-1397). At its type locality (L-1906) this species was found syntopically with A. baeus , A. henryi n. sp., A. schuhi n. sp., and A. spicatus . Additionally, A. sitesi was collected with A. brailovskyi n. sp. at Finca Prusia (12-V-1985), Río Matasano (L-1348), Río Prusia (L-1345), and the Tenejapa municipality (14-VII-1964).

Etymology. It is my (DRV) pleasure to name this species in honor of Professor Robert. W. Sites, my former doctoral advisor at the University of Missouri and coauthor of this manuscript. I am grateful for his guidance, help, and friendship throughout these years.

Repositories. The holotype and some paratypes will be deposited in the Colección Entomológica del Instituto de Ecología A.C. (Xalapa); additional paratypes will be deposited in the California Academy of Sciences (San Francisco), Colección Nacional de Insectos (Mexico City), Enns Entomology Museum (Columbia), Snow Entomological Museum Collection (Lawrence), and the United States National Museum of Natural History (Washington D.C.)

Type material examined. HOLOTYPE ♀. MÉXICO: OAXACA: Mpio. San Gabriel Mixtepec, km 194 carr. Puerto Escondido-Oaxaca, San Gabriel Mixtepec, Río Rana , 16º06’06.3’’N, 97º03’52.9’’W, 712 m, 03-Apr-2015, L-1906, DRV, Sites, Shepard, Barr & PRH colls . PARATYPES: same data as holotype (2♂, 2♀ CNIN; 10♂, 7♀ IEXA; 5♂, 4♀ UMC) ; Mpio. Jalapa de Díaz, Sto. Domingo, Río Sto. Domingo , 18°02’15.9’’N, 96°32’57.2’’W, 100 m, L-1881, 25-Mar-2015, DRV, Sites, Shepard, Barr & PRH colls. (2♂, 6♀ IEXA; 1♂, 1♀ UMC) ; Mpio. Putla Villa de Guerrero, Pluta de Guerrero, 17º02’21.5’’N, 97º54’42.9’’W, 767 m, 30-May-2012, L-1397, DRV & PRH colls. (1♂ UMC) ; Mpio. Sta. Maria Tecomavaca, carr. Tehuacán-San Francisco Telixtlahuaca, 16 km S of San Juan de los Cués , Río Salado , 17º55’50.5’’N, 97º00’04.2’’W, 544 m, 01-Jun-2012, L-1407, DRV & PRH colls. (1♂ UMC) . CHIAPAS: Mpio. Altamirano, Cuauhtemoc, Balneario Tzaconejá , Río Tzaconejá , 16°41’17.5’’N, 92°01’03.0’’W, 1172 m, 28-Mar-2015, L-1886, DRV, Sites, Shepard, Barr & PRH colls. (6♂, 3♀ IEXA; 4♂ UMC) ; Mpio. Am- atengo de la Frontera, Barrio Sabinalito, Río Agua Caliente , 15°25’0.1’’N, 92°08’33.7’’W, 942 m, L-1898, 31-Mar- 2015, DRV, Sites, Shepard, Barr & PRH colls. (4♂ IEXA) ; [Mpio. Ángel Albino Corzo], Finca Prusia, 10-V-85, M. Vértiz / Colección del Instituto de Biología , UNAM. México, D.F (1♂ CNIN) ; [Mpio. Ángel Albino Corzo], Finca Prusia, 12-V-85, F Arias / Colección del Instituto de Biología , UNAM. México, D.F (1♂, 2♀ CNIN) ; [Mpio. Ángel Albino Corzo], Finca Prusia, 12-V-85, H Velasco / Colección del Instituto de Biología , UNAM. México, D.F (3♂ CNIN) ; [Mpio. Ángel Albino Corzo], Finca Prusia, 12-V-85, M Vértiz / Colección del Instituto de Biología , UNAM. México, D.F (1♀ CNIN) ; Mpio. Ángel Albino Corzo, 1 km S of Finca Prusia, Río Prusia , 15º43’23.3’’N, 92º47’46.5’’W, 1010 m, 18-May-2012, L-1345, DRV & PRH colls. (1♂, 4♀ UMC) ; Mpio. Frontera Comalapa, El Caracol, 8 km S of Frontera Comalapa, Río Grijalva , 15°36’07.0’’N, 92°09’14.5’’W, 677 m, 31-Mar-2015, L- 1897, DRV, Sites, Shepard, Barr & PRH colls. (1♂ IEXA) ; Mpio. Huixtla, Huixtla, Río Huixtla , 15°08’59.9’’N, 92°27’04.6’’W, 67 m, 31-Mar-2015, L-1899, DRV, Sites, Shepard, Barr & PRH colls. (1♂ IEXA) ; Mpio. Ixtapa, Ixtapa , 16º48’43.7’’N, 92º54’30’’W, 1030 m, 17-May-2012, L-1341, DRV & PRH colls. (6♂, 3♀ IEXA) ; [Mpio. Ixtapa], Ixtapa , #132, IV-27-1941, IJ Cantrall / Ambrysus lunatus menoides La Rivers PARATYPE / Ira La Rivers Collection Bequeathed to the California Academy of Sciences-1978 (1♀ CAS) ; Mpio. Ixtapa, Río Lajas at Pte. Río Lajas , 16º50’42.6’’N, 92º54’01.7’’W, 1020 m, 17-May-2012, L-1340, DRV & PRH colls. (2♂, 1♀ UMC) ; same but 28-Mar-2015, L-1885, DRV, Sites, Shepard, Barr & PRH colls. (10♂, 10♀ CNIN; 20♂, 21♀ IEXA; 6♂, 15♀ UMC) ; [Mpio. Ixhuatán], 4 mi N of Tapiula [Tapilula], CL 1097, 5 May 1964, JT & MS Polhemus (1♂, 1♀ USNM) ; [Mpio. Ocosingo], Ocosingo , June 25 1950, C & M Goodnight & L Stannard, mountain stream / Chiapas VI-25-57, Mex. Stannard (1♂ SEMC) ; Mpio. Siltepec, km 72 carr. Jaltenango-Siltepec, nr. Nuevo Galeana , 15º35’54.9’’N, 92º32’28.9’’W, 933 m, L-1349, 19-May-2012, DRV & PRH colls. (2♂, 1♀ UMC) ; Mpio. Siltepec, km 92 carr. Jaltenango-Siltepec, Campo Aéreo , Río Bravo , 15º35’17.9’’N, 92º28’02.3’’W, 1068 m, 19-May-2012, L-1350, DRV & PRH colls. (1♂, 1♀ UMC) ; Mpio. Siltepec, Matasano, Río Matasano , 15º36’13.7’’N, 92º33’37.1’’W, 950 m, 19-May-2012, L-1348, DRV & PRH colls. (6♂, 6♀ IEXA; 16♂, 19♀ UMC) ; Mpio. Solosuchiapa, El Beneficio, Río La Sierra , 17°21’01.1’’N, 93°00’21.1’’W, 303 m, 27-Mar-2015, L-1884, DRV, Sites, Shepard, Barr & PRH colls. (1♂ UMC) ; Mpio. Solosuchiapa, Solosuchiapa, Río La Sierra , 17º25’40.5’’N, 93º01’35.7’’W, 122 m, 17- May-2012, L-1339, DRV & PRH colls. (1♂ UMC) ; [Mpio. Soyaló], Soyalo, Rio Blanco , CL 1086, 4 May 1964, JT & MS Polhemus / C.J. Drake Accession (16♂, 10♀ USNM) ; Mpio. Tenejapa, ponds in stream above Habenal / 14.VII.1964, coll. D Breedlove / C.J. Drake Accession / CAS (2♂ USNM) ; Rio Laja [s] nr Bochil, CL 668, I-6-74, JT Polhemus (9♂, 5♀ USNM) ; Soyalo, Rio Lajas , CL 1087, 4 May 1964, JT & MS Polhemus / A. guttatipennis close, No! / C.J. Drake Accession (1♀ USNM) . GUATEMALA: HUEHUETENANGO: Rio Nentón , ca. 8 km NE of La Laguna, 10-May-2013, 15.79915º N, 91.88951ºW, 613 m, RS Zack coll. (1♀ WSUC) .

Figures

FIGURE 3. Distribution of Ambrysus brailovskyi n. sp., A. henryi n. sp., A. schuhi n. sp., and A. sitesi n. sp. in Mexico and Guatemala (color coded stars indicate the type localities).

FIGURE 8. Structures of Ambrysus sitesi n. sp. (A) dorsal habitus of holotype, (B) sternum VI and subgenital plate of female (terminal abdominal segments removed), (C) 6th and 7th abdominal terga of male, (D) 8th abdominal tergum of male, (E) ventral surface of male phallosoma, (F) genital capsule of male (phallosoma removed). ll = lateral lobe, plc = posterolateral corner.

FIGURE 9. Type locality of Ambrysus sitesi n. sp. at Río Rana (Oaxaca, Mexico) with Robert W. Sites in the inset.