Ambrysus schuhi Reynoso & Sites, 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 : 294-297

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Ambrysus schuhi Reynoso & Sites


Ambrysus schuhi Reynoso & Sites NEW SPECIES

( Figs. 3 View FIGURE 3 , 6–7 View FIGURE 6 View FIGURE 7 )

Description. Macropterous female. HOLOTYPE, length 13.87; maximum width 8.30. Paratypes (n = 9), length 12.48–14.04 (mean = 13.12); maximum width 7.84–8.48 (mean = 8.10). General shape ovate; widest across embolia ( Fig. 6A View FIGURE 6 ). Overall dorsal coloration of hemelytra brown to dark brown with light brown marks; head light brown with dark brown marks; pronotum brown with dark brown marks; legs brown. Dorsal surface coarsely punctate. Ventral coloration of head and thorax brown, abdomen with yellowish brown pubescence.

Head. Head length 2.04; maximum width 3.92. Mostly brown with dark brown marks along midline and posteriorly; coarsely punctate. Eyes convergent anteriorly, synthlipsis 1.80; 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 10.7% of head length; posterior margin between eyes strongly convex, extending posteriorly 30.6% of head length. Labrum width 2.1× length, evenly rounded. Labium with three visible yellowish brown segments, darkening distally, extending 0.75 beyond labrum not including extruded stylets. Antennal proportions 5:17:22:11, length 1.37, extending to lateral margin of eye, elongate hairs on segments 3 and 4.

Thorax. Pronotum coarsely punctate, ground color brown, dark brown marking posteromedially, 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 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 2.4× length; length at midline 2.96; maximum width at posterolateral corners 7.37. Prothorax ventrally pruinose throughout, except laterally; apices of propleura meeting at midline, not appressed to prosternellum; propleuron yellowish brown, 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, brown coloration on anterior and posterior corners and along midline, width 2.2× length, width 5.00, length 2.24. Hemelytra densely punctate, brown to dark brown, length 10.0 (chord measurement); corium dark brown, faint brown ovoid and yellowish brown comma-shaped markings at lateral and posterior margins, respectively. Clavus dark brown, indistinct light brown marking at mid-length in mesal half, length 4.0× width, length 5.45, width 1.36; claval commissure dark brown, length 1.27. Embolium length 4.20, greatest width 1.17; lateral margin convex, light brown in anterior 2/3, brown posteriorly. Membrane dark brown ( Fig. 6A View FIGURE 6 ). Hindwings extending to posterior margin of tergum VI. Mesobasisternum tumescence negligible, with sulcus on midline continuing through triangular mesosternellum. Metasternellum (= metaxyphus) transverse, subtriangular, with median carina.

Legs. All leg segments yellowish brown to 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, 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 on 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 3.25, tibia 2.54, tarsus 0.52; middle leg, femur 2.91, tibia 2.75, tarsomeres 1–3, 0.27, 0.60, 0.58; hind leg, femur 4.00, tibia 4.48, tarsomeres 1–3, 0.34, 1.05, 0.75.

Abdomen. Dorsally with lateral margins of III–VI exposed, each dark brown in anterior 1/3 and light brown posteriorly; lateral margins of II–basal half of III smooth and distal half of III–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 brown, with dense pile of fine hairs. Lateral margin with thin, glabrous band. Glabrous rounded to oval patches near spiracles on laterosternites II–VII. Mediosternite VII (subgenital plate) asymmetrical, width 1.1× length; length at midline 1.45; maximum width 1.69; with pointed lateral lobe at apex of left margin; posterolateral corners pointed, asymmetrical, right posterolateral corner wider, both corners posteriorly produced further than central lobe; wide central lobe notched giving the appearance of two rounded lobes ( Fig. 6B View FIGURE 6 ).

Macropterous male. Paratypes (n = 10), length 11.68–12.64 (mean = 12.19); maximum width 7.36–7.84 (mean = 7.62). 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 in basal 2/3, curved to right at approximately 90 degree angle in apical 1/3, apex pointed ( Fig. 6C View FIGURE 6 ). Medial lobes of tergum VIII (pseudoparameres) symmetrical, posterolaterally produced, posterolateral corner narrowly rounded, extending posteriorly further than posteromesal corner ( Fig. 6D View FIGURE 6 ). Phallosoma elongate, linear, slender, slightly constricted basally; endosomal sclerites subtriangular, knob-like apically, with conspicuous denticles, right sclerite basally produced further than left sclerite ( Fig. 6E View FIGURE 6 ). Parameres symmetrical, almost as long as maximum width, mesal margin rounded, setae emanating from distal 1/3 of dorsal surface. Proctiger almost as long as width at base. Pygophore with elongate setae sparsely distributed over most of surface, with thick brush of elongate setae on posterior margin ( Fig. 6F View FIGURE 6 ).

Discussion. The general morphology of the female SGP, the male AGP, and the endosomal sclerites exhibited by A. schuhi suggest a close relationship with A. cosmius La Rivers.

Diagnostic features and comparative notes. Females have a diagnostic SGP that presents a pointed lateral lobe at the apex of the left margin, just basal to the left posterolateral corner. Also, the pointed posterolateral corners are asymmetrical with that on the right generally wider. A similar SGP is also present in A. cosmius , although the lateral lobe on the left margin is rounded and at mid-length and the posterolateral corners are symmetrical. Males of A. schuhi exhibit a characteristic AGP that is particularly long and pointed in the apical third, whereas A. cosmius presents a comparable AGP, but is longer and the apex is anterolaterally directed (laterally directed in A. schuhi ).

Habitat description. The type locality at El Rosario (L-1394) is in the western area of the Mexican state of Oaxaca, at an elevation of 361 meters. The stream at the type locality is shallow and approximately 5 meters wide. The river bottom is mainly composed of gravel ( Fig. 7 View FIGURE 7 ). The microhabitat where we collected specimens of this species was among rocks and algae along the stream margins.

Distribution. This species is present in the southern area of the Mexican states of Guerrero and Oaxaca ( Fig. 3 View FIGURE 3 ). Ambrysus schuhi is distributed in the Mexican Pacific Coast (Guerrero) and Sierra Madre del Sur (Oaxaca) biogeographic provinces. At its type locality (El Rosario, Oaxaca) this species was collected syntopically with A. baeus and A. spicatus . At Río Rana, in May 2012 (L-1380), A. schuhi was found syntopically with A. baeus , A. pulchellus , and the new species A. henryi . Also, at Río Rana, but in April 2015 (L-1906), it was collected with A. baeus , A. spicatus , and the new species A. henryi and A. sitesi . At the locality northeast of San Pedro Amuzgos (L-1391) we found this species with A. baeus , A. pudicus , A. pulchellus , and A. spicatus . Additionally, at the locality south of El Tapanco (L-1393) A. schuhi was collected with the congeners A. angularis and A. pulchellus , as well as with Cataractocoris marginiventris Usinger.

Etymology. It is our pleasure to name this species in honor of our dear colleague Professor Randal T. Schuh, of the American Museum of Natural History, to commemorate the astounding work he has conducted on the group of “True Bugs.” Recently, during the VI Quadrennial Meeting of the International Heteropterists’ Society (La Plata, Argentina), Dr. Schuh was awarded with the newly institutionalized Carl Stål Medal, to recognize his accomplishments on the study of Heteroptera, which include the description of approximately 100 genera and 600 species of insects.

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 Colección Nacional de Insectos (Mexico City), Enns Entomology Museum (Columbia), University of Michigan Museum of Zoology (Ann Arbor), and the United States National Museum of Natural History (Washington D.C.) .

Type material examined. HOLOTYPE ♀. MÉXICO: OAXACA: Mpio. Sta. Maria Zacatepec, km 179 carr. Sta. Maria Zacatepec-Putla, El Rosario , Pte. El Rosario , 29-May-2012, L-1394 / 361 m, 16º51’34.6’’N, 97º58’44.7’’W, DRV & PRH colls GoogleMaps . PARATYPES: same data as holotype (3♂ IEXA; 6♂, 6♀ UMC) GoogleMaps ; Mpio. Mesones Hidalgo, km 173 carr. Sta. Maria Zacatepec-Putla, Pte. La Junta , 29-May-2012, L-1395 / 396 m, 16º53’59.7’’N 97º58’02’’W, DRV & PRH (1♂ UMC) GoogleMaps ; Mpio. San Gabriel Mixtepec, Río Rana, km 194 carr. Puerto Escondido- Oaxaca, San Gabriel Mixtepec , L-1380 / 27-May- 2012, 712 m, 16º06’06.3’’N 97º03’52.9’’W, DRV & PRH colls. (1♂, 1♀ UMC) GoogleMaps ; same but 3-Apr-2015, L-1906, DRV, Sites, Shepard, Barr & PRH colls., rocks & gravel (5♂, 1♀ IEXA; 3♂, 1♀ UMC) ; [Mpio. San Gabriel Mixtepec], Sn. Gabriel Mixtepec, 20-V-84, M García / Colección del Instituto de Biología , UNAM. México D.F. (1♂ CNIN; 1♂, 1♀ USNM) ; Mpio. Sta. Maria Zacatepec, km 189 carr. Sta. Maria Zacatepec-Putla , S of El Tapanco, L-1393 / 29-May- 2012, 341 m, 16º47’28.3’’N 97º59’20.4’’W, DRV & PRH (2♂ UMC) GoogleMaps ; Mpio. Sta Maria Zacatepec, Km 201 carr. Mártires de Tacubaya-Santa Maria Zacatepec ca. 13 km NE of San Pedro Amuzgos, L-1391 / 29-May- 2012, 276 m, 16º42’18.9’’N 98º00’52.9’’W, DRV & PRH (1♂ UMC) GoogleMaps . GUERRERO: stream tributary to Laguna Tres Palos , about 22 miles from Acapulco on highway to Mexico City, III:22:1951 RR & M Miller (2♂, 1♀ UMMZ) .


Coleccion Nacional de Insectos, Universidad Nacional Autonoma de Mexico


Smithsonian Institution, National Museum of Natural History


University of Michigan, Museum of Zoology













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