Ambrysus morelosensis Reynoso & Sites, 2022

Reynoso-Velasco, Daniel & Sites, Robert W., 2022, Revision of the Ambrysus signoreti Stål species complex (Heteroptera: Naucoridae Ambrysinae). Section 1., Zootaxa 5214 (3), pp. 421-439 : 429-433

Ambrysus morelosensis Reynoso & Sites NEW SPECIES

( Figs. 5 –7)

Description. Macropterous female. HOLOTYPE, length 12.87; maximum width 8.12. Paratypes (n = 1), length 11.75; maximum width 7.63. General shape elliptical; widest across embolia. Overall dorsal coloration of hemelytra dark-brown with light-brown marks; head light-brown; pronotum brown with dark-brown marks; legs brown ( Fig. 5A ). Dorsal surface coarsely punctate. Ventral coloration of head and thorax light-brown, abdomen with yellowishbrown pubescence.

Head. Head length 1.73; maximum width 3.41. Mostly light-brown with dark-brown marks along midline and posteriorly; coarsely punctate. Eyes convergent anteriorly, synthlipsis 1.73; thin band of cuticle along posterolateral margin of eye; eyes not raised above level of vertex or pronotum. Anterior margin between eyes convex, extending anteriorly in front of eyes 10.71% of head length; posterior margin between eyes strongly convex, extending posteriorly 28.57% of head length. Labrum width 2.00× length, evenly rounded. Labium with three visible light-brown segments, darkening distally, extending 0.76 beyond labrum not including extruded stylets. Antennal proportions 5:14:19:9, length 0.94, not reaching lateral margin of eye, elongate hairs on segment 4 and distal half of 3.

Thorax. Pronotum coarsely punctate, ground color brown, dark-brown marking medially, dark-brown line behind eye; transverse sulcus marking anterior border of transverse band in posterior 1/3; transverse band brown; lateral margins light-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 2.86× length; length at midline 2.35; maximum width at posterolateral corners 6.75. Prothorax ventrally pruinose throughout, except laterally; apices of propleura meeting at midline, not appressed to prosternellum; propleuron light-brown, 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, brown, two reniform to ovate dark-brown marks medially, width 2.02× length, width 4.52, length 2.23. Hemelytra densely punctate, mostly dark-brown, length 9.20 (chord measurement); corium dark-brown, lightbrown irregularly shaped and checkmark-shaped markings at lateral and posterior margins, respectively. Clavus dark-brown, light-brown at mid-length and apically, length 3.80× width, length 4.71, width 1.24; claval commissure black, length 1.24. Embolium length 3.53, greatest width 1.30; lateral margin convex, yellowish-brown in anterior 2/3, dark-brown posteriorly. Membrane dark-brown ( Fig. 5A ). Hindwings extending to posterior margin of tergum VI. Mesobasisternum midventral tumescence negligible, with sulcus on midline continuing through triangular mesosternellum. Metasternellum (= metaxyphus) transverse, subtriangular, with median carina.

Legs. All legs segments 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, 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 reddishbrown spines; mesolateral rows intermixed with combs of 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 to brown 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 3.10, tibia 2.41, tarsus 0.55; middle leg, femur 2.97, tibia 2.79, tarsomeres 1–3, 0.18, 0.54, 0.66; hind leg, femur 3.90, tibia 4.65, tarsomeres 1–3, 0.31, 1.00, 0.90.

Abdomen. Dorsally with lateral margins of III–VIII exposed, IV–VI each dark-brown in anterior 1/3 and yellowish-brown posteriorly; lateral margins of II to basal half of III smooth, 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. Ventrally yellowish-brown to brown, with dense pile of fine hairs. Lateral margin with thin, glabrous band. Glabrous rounded to oval patches clearly visible around spiracles on laterosternites II–VI. Mediosternite VII (subgenital plate) asymmetrical, width 1.36× length; length at midline 1.26; maximum width 1.72; left margin with broadly rounded lobe occupying its entire length; right margin with small apical lobe; posterolateral corners short, pointed, subtriangular, extending posteriorly further than the central lobe; central lobe poorly developed, inconspicuous, shallowly concave medially ( Fig. 5B ).

Macropterous male. Paratypes (n = 1), length 11.88; maximum width 7.75. 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 gently curved to right close to base, distal 1/3 angled to right to continue perpendicular to body axis ( Fig. 5C ). Medial lobes of tergum VIII (pseudoparameres) symmetrical, posterolateral corners narrowly rounded, posteromesal corners broadly rounded, posterior margin concave ( Fig. 5D ). Phallosoma elongate, linear, slender, broadly rounded dorsoapically; left endosomal sclerite reduced, with few small and inconspicuous denticles; right endosomal sclerite vestigial, rounded, without denticles ( Fig. 5E ). Parameres symmetrical, slightly longer than maximum width, mesal margin rounded, setae emanating from distal half of dorsal surface. Proctiger almost as long as width at base. Pygophore with anterior margin obtuse to subobtuse medially, elongate setae sparsely distributed over most of surface, with thick brush of elongate setae on posterior margin ( Fig. 5F ).

Diagnosis. This species can be distinguished from the other three in this section by the female SGP with a large, plate-like, rounded lobe on the left margin and symmetrical subtriangular posterolateral corners ( Fig. 5B ). Additionally, the male AGP tapers distally to a pointed and laterally directed apex ( Fig. 5C ) and the pseudoparamere posterolateral corners are narrowly rounded ( Fig. 5D ).

Comparative notes. Ambrysus morelosensis presents a unique female SGP; none of the other three species in this group exhibits a similar large lobe on the left margin. The only other two species in the complex with a "comparable" feature are A. scalenus La Rivers and A. sitesi Reynoso ; nonetheless, the lobe is truncate in A. scalenus and in both species it is located at mid-length, not occupying the entire margin as in the new species. Additionally, these two species present the central lobe almost at the same level as the posterolateral corners, whereas in A. morelosensis n. sp. the central lobe is poorly expressed, almost flat, and clearly below the level of the posterolateral corners. This new species is superficially similar to A. sitesi ; this similarity together with the "comparable" female SGP and the similar male pseudoparameres suggest a close relationship.

Variation. The single female paratype exhibits the posterior margin of the SGP evenly concave between the blunt posterolateral corners and the small apical lobe on the right margin is absent.

Habitat description. The type locality, Río Amacuzac at Huajintlán, is in the southwestern area of the Mexican state of Morelos at an elevation of 931 meters. The first author visited the type locality (L-1989) three decades after the type specimens were collected; unfortunately, no more specimens of A. morelosensis were found, only numerous specimens of A. hydor La Rivers. At the time, the river at the type locality was approximately 40 meters wide and shallow, exposing boulders and cobble ( Fig. 6 ).

Distribution. Ambrysus morelosensis is known from only two localities, one in the state of Michoacán and the other in Morelos, in central-western and central Mexico, respectively (Fig. 7). Both localities are at elevations below 1,000 meters and within the limits of the Balsas Basin biogeographical province; more specifically, in the middle (Morelos) and lower (Michoacán) sections of the basin.

Etymology. The specific epithet " morelosensis " is in reference to the central Mexican state of Morelos, where the type locality is located. The species name means The Ambrysus from Morelos.

Repository. The holotype and paratypes will be deposited in the Colección Entomológica del Instituto de Ecología A.C. (IEXA).

Type material examined. HOLOTYPE ♀. MEXICO: MORELOS: [Mpio. Amacuzac, Río Amacuzac at Huajintlán], km 50 [on carr. 95] Cuernavaca-Taxco , [18º36'35.56''N, 99º25'40.38''W, 931 m], 09-III-1985, M. Albores coll. PARATYPES: same data as holotype (1♂ IEXA) . MICHOACÁN: Mpio. Buenavista, Buenavista River at Buenavista Tomatlán , below dam, 19º12'57.8''N, 102º34'30.2''W, 440 m, 24-XII-2012, L-1481, ReynosoVelasco, D. coll. (1♀ IEXA) .

Figures

FIGURE 5. Structures of Ambrysus morelosensis Reynoso & Sites n. sp. (A) dorsal habitus of female holotype, (B) sternum VI and subgenital plate of female holotype (terminal abdominal segments digitally 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). al = apical lobe, res = right endosomal sclerite.

FIGURE 6. Type locality of Ambrysus morelosensis Reynoso & Sites n. sp. at Río Amacuzac, in the Mexican central state of Morelos