Ambrysus altiplanus Reynoso, 2021

Reynoso-Velasco, Daniel, 2021, A new species of Ambrysus Stål from the Central Mexican Plateau and new state records for species of the genus in the country (Heteroptera: Nepomorpha Naucoridae), Zootaxa 5005 (3), pp. 304-316 : 305-308

Ambrysus altiplanus Reynoso NEW SPECIES

( Figs. 1–4 )

Description. Macropterous female. HOLOTYPE, length 14.62; maximum width 9.00. Paratypes (n = 10), length 13.12–14.00 (mean = 13.67); maximum width 8.40–8.92 (mean = 8.62). General shape ovate; widest across embolia ( Fig. 1A ). Overall dorsal coloration of hemelytra dark-brown with yellowish to light-brown marks; head and pronotum light-brown with dark-brown marks; legs light-brown. Dorsal surface coarsely punctate. Ventral coloration of head and thorax yellowish, abdomen with yellowish pubescence.

Head. Head length 2.10; maximum width 4.15. Mostly light-brown with dark-brown marks along medial line, laterally, and posteriorly; coarsely punctate. Eyes convergent anteriorly, synthlipsis 2.04; 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 9.5% of head length; posterior margin between eyes strongly convex, extending posteriorly 28.5% of head length. Labrum width 2.3× length, evenly rounded. Labium with three visible light-brown segments, darkening distally, extending 0.60 beyond labrum not including extruded stylets. Antennal proportions 5:11:16:6, length 0.95, not reaching lateral margin of eye, elongate hairs on segment 4 and distal half of 3.

Thorax. Pronotum coarsely punctate, ground color brown, profuse dark-brown marking, two dark-brown lines behind eyes; transverse sulcus marking anterior border of transverse band in posterior 1/4; transverse band yellowish anteriorly, light-brown posteriorly; lateral margins yellowish-brown posteriorly, 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 2.6× length; length at midline 2.91; maximum width at posterolateral corners 7.63. 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 along lateral margins, width 2.1× length, width 5.02, length 2.29. Hemelytra densely punctate, dark-brown, length 10.50 (chord measurement); corium dark-brown, spotted faint brown and yellowish subtriangular markings at lateral and posterior margins, respectively. Clavus mostly dark-brown, length 3.7× width, length 5.58, width 1.48; claval commissure black, length 1.60. Embolium length 4.34, greatest width 1.36; lateral margin convex, light-brown in anterior 2/3, dark-brown posteriorly. Membrane dark-brown ( Fig. 1A ). Hindwings extending to middle of tergum VII. Mesobasisternum midventral tumescence negligible, with sulcus on midline continuing through triangular mesosternellum. Metasternellum (= metaxyphus) transverse, subtriangular, with median carina.

Legs. All legs segments light-brown to brown. Profemur 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; 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. Mesotibiae with ventrolateral and dorsolateral rows of stout reddish-brown spines; mesolateral rows intermixed with combs spines. Metatibia with ventrolateral and dorsolateral rows of stout reddish-brown spines. Meso- and metatibiae with semi-circlet of spines at apex of 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 3.34, tibia 2.54, tarsus 0.62; middle leg, femur 3.28, tibia 3.03, tarsomeres 1–3 0.36, 0.60, 0.70; hind leg, femur 4.21, tibia 5.08, tarsomeres 1–3 0.36, 1.17, 0.94.

Abdomen. Dorsally with lateral margins of III–V exposed, each dark-brown in anterior 1/3 and light-brown posteriorly; lateral margins of II to 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) right angled, III–VI acute, spinose. Ventrally yellowish, with dense pile of fine hairs. Lateral margin with thin, glabrous band. Glabrous rounded to oval patches around spiracles on laterosternites II–VII. Mediosternite VII (subgenital plate) symmetrical, width 1.2× length; length at midline 1.54; maximum width 1.90; lateral margins with low lateral and indistinct apical lobes at mid-length and apically, respectively; posterolateral corners short, pointed; central lobe faintly notched medially, produced posteriorly slightly further than posterolateral corners ( Fig. 1B ).

Macropterous male. Paratypes (n = 10), length 12.64–13.28 (mean = 12.90); maximum width 7.88–8.32 (mean = 8.11). 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 curved to right close to base, angled again close to apical third, apex blunt ( Fig. 1C ). Medial lobes of tergum VIII (pseudoparameres) symmetrical, posterolateral and posteromesal corners broadly rounded ( Fig. 1D ). Phallosoma elongate, linear, slender; endosoma lightly sclerotized apically on left side, lobe-shaped, granulose ( Fig. 1E black arrow); endosomal sclerites knob-like apically, with conspicuous denticles on right sclerite, inconspicuous on left sclerite; right sclerite extending basally further than left sclerite ( Fig. 1E ). 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. 1F ).

Diagnostic features and comparative notes. Females of this species exhibit a characteristic subgenital plate (SGP) with low lateral and indistinct apical lobes on the lateral margins ( Fig. 1B ). The only other species in the A. signoreti species complex with a similar SGP is A. dyticus La Rivers , described from Guatemala ( La Rivers 1953a). The morphology of the SGP of these two species is unique among species in the complex, because in addition to the lateral lobes, they exhibit apical lobes on the lateral margins. The apical lobes in the new species are low and inconspicuous, while those in A. dyticus are clearly noticeable and pointed. Additionally, the central lobe on the posterior margin of A. dyticus appears wide and clearly notched medially, whereas this lobe is narrower and only faintly notched medially in A. altiplanus n. sp. Males of the new species present the left side of the endosoma lobate and lightly sclerotized. A similar characteristic has been observed only in A. magniceps La Rivers and A. scalenus La Rivers , both members of the same complex.

Habitat description. The type locality at Río Mezquital, close to the town of Nombre de Dios, is in the southeastern area of the Mexican state of Durango, on the eastern slopes of the Sierra Madre Occidental mountain range, at an elevation of 1731 meters. At the type locality the river is approximately 20 meters wide, with boulders and cobble ( Fig. 2 ). The microhabitat where most of the specimens were collected was cobble in the protected area preceding riffles ( Fig. 3 ).

Distribution. Ambrysus altiplanus n. sp. is distributed in north-central Mexico ( Fig. 4 ); in the west- (Chihuahua, Durango, Zacatecas) and southern area (Guanajuato, Hidalgo, Jalisco, Querétaro, San Luis Potosí, Zacatecas) of the Central Mexican Plateau, in the Chihuahuan Desert biogeographic province, at elevations of 1500–2100 meters.

Etymology. The specific epithet, from the word altiplano (= high plateau), is in reference to the north-central Mexican area inhabited by this species, “ The Ambrysus from the Altiplano.”

Repository. The holotype and some paratypes will be deposited in the Colección Entomológica at Instituto de Ecología A.C. ( IEXA) ; additional paratypes will be deposited in the California Academy of Sciences ( CAS) , Colección Entomológica at Universidad Autónoma de Querétaro ( UAQE) , Colección Nacional de Insectos ( CNIN) , University of Michigan Museum of Zoology ( UMMZ) , University of Missouri ( UMC) , and the United States National Museum of Natural History ( USNM) .

Type material examined. HOLOTYPE ♀. MEXICO: DURANGO: Mpio. Nombre de Dios, km 239 carr. MEX45 Vicente Guerrero-Durango, Pte. Melones , Río Mezquital , 23°52’17.3’’N, 104°16’04.7’’W, 1731 m, 29- Jun-2013, L-1591, Reynoso-Velasco coll. PARATYPES: same data as holotype (2♂, 2♀ IEXA; 22♂, 23♀ UMC) ; same but 04-Jan-2014, L-1721 (2♂, 2♀ CAS; 15♂, 6♀ UMC; 2♂, 2♀ USNM) ; Mpio. San Bernardo, San Ber- nardo, Río Sextín , 26°00’05.0’’N, 105°30’17.6’’W, 1607 m, 01-Jan-2014, L-1711, Reynoso-Velasco coll. (4♂, 1♀ UMC) ; Mpio. Súchil , Corralitos , Arroyo Corralitos , 23°31’11.1’’N, 104°08’13.3’’W, 2091 m, 04-Jan-2014, L-1720, Reynoso-Velasco coll. (4♂, 1♀ UMC) . CHIHUAHUA: Mpio. Balleza, El Padre, 6 km W of Balleza, Río de Agujas , 26°57’01.8’’N, 106°24’00.8’’W, 1572 m, 29-Dec-2013, L-1701, Reynoso-Velasco coll. (2♂ UMC) . GUANAJUATO: Mpio. Santa Cruz de Juventino Rosas, Arroyo Piedras Anchas [20º39’21.19’’N, 100º59’27.6’’W, 1765 m], 20-Nov-2010, R. Novelo coll. (1♂, 3♀ IEXA) . HIDALGO: Mpio. Tecozautla, Río San Francisco at El Riíto , [7 km N of Tecozautla, 20º34’35.51’’N, 99º37’19.13’’W, 1590 m], 27-Mar-1996, J.A. Gómez-Anaya coll. (1♂, 1♀ CNIN; 2♂, 3♀ IEXA) ; same but 18-Apr-1996 (8♀ IEXA) ; same but 8-May-1996 (6♀ IEXA) ; same but 18-Jun-1996, A. Gómez, R. Arce & R. Novelo colls. (3♀ IEXA) ; Mpio. Tecozautla , Río San Francisco ( El Riíto ), 20º40’01’’N, 99º30’06’’W, 1590 m, Jul-1996, A. Gómez coll. (3♀ CNIN; 4♀ IEXA) ; [Mpio. Tecozautla], Río San Juan , [6 km NW of Gandhó, 20º33’48.9’’N, 99º44’11.32’’W, 1719 m], 28-Mar-1996, J.A. Gómez-Anaya coll. (1♂, 1♀ CNIN; 2♂, 1♀ IEXA) . JALISCO: [Mpio. Degollado, Huáscato], trib. of Rio Lerma , [Prob. 20º28’38.80’’N, 102º15’54.81’’W, Approx. 1600 m], 13-May-1977, M.L. Smith & E.M. Baker / Ambrysus sp. Det. E. Bright, July 2003 (1♀ UMMZ) ; [Mpio. Yahualica de González Gallo], 5 mi N of Yahualica, Rio Ancho, trib. of Rio Verde [21º13’47.85’’N, 102º51’2.48’’W, 1670 m], 15-Mar-1961, Miller & Huddle colls., M61-27 (1♂ UMMZ) . QUERÉ- TARO: Mpio. Tolimán, Panales, Rio Estorax [Extóraz], 20º52.33N, 99º59.37W, 1800 msnm, R. Jones coll. (1♂ IEXA; 1♂, 1♀ UAQE) . SAN LUIS POTOSÍ: [Mpio. Santa María del Río] Rio Villeto [Prob. 6.3–9 mi S of Sta María on Hwy 57], Spring 1969, Barbour & Douglass (5♂, 9♀ USNM) ; [Mpio. Santa María del Río] Sta. María del Río , 9-Dec-1973, CL602, J.T. Polhemus / Ambrysus magniceps La Rivers Det. J.T. Polhemus / looks good! I-90 JTP / C.J. Drake Accession (1♂ USNM) . ZACATECAS: Mpio. Sain Alto, Sain Alto, Arroyo Frío , 23°33’36.3’’N, 103°15’50’’W, 2034m 05-Jan-2014, L-1722, Reynoso-Velasco coll. (3♂ UMC) .

Figures

FIGURE 1. Structures of Ambrysus altiplanus Reynoso n. sp. (A) dorsal habitus of female holotype (yellow and white arrows indicate faint brown and yellowish marks on corium, respectively), (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 (black arrow indicates lobe-shaped portion of endosoma), (F) genital capsule of male (phallosoma removed). agp = accessory genitalic process, al = apical lobe, cl = central lobe, emb = embolium, les = left endosomal sclerite, ll = lateral lobe, pct = proctiger, plc = posterolateral corner, pmc = posteromesal corner, pp = pseudoparamere, pr = paramere, pyg = pygophore, res = right endosomal sclerite, sgp = subgenital plate.

FIGURE 2. Type locality of Ambrysus altiplanus Reynoso n. sp. at Río Mezquital, in the Mexican northwestern state of Durango. Arrow indicates specific area in next figure.

FIGURE 3. Detail of the area at the type locality where most of the specimens of Ambrysus altiplanus Reynoso n. sp. were collected.

FIGURE 4. Distribution of Ambrysus altiplanus Reynoso n. sp. (star indicates the type locality).