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 : 425-433

Ambrysus cosmius La Rivers

( Figs. 1A , 2–4 )

A. cosmius La Rivers 1953 : Univ. Kans. Sci. Bull., 35: 1329–1331 (original description).

Supplemental description. Female. Mediosternite VII (SGP) asymmetrical; left margin with rounded, marginally sclerotized, lateral lobe at mid-length; right margin with inconspicuous lobe at mid-length; central lobe shallowly concave medially, giving the appearance of two lobes; posterolateral corners elongate, narrowly rounded apically, extending posteriorly further than central lobe ( Fig. 2B ).

Male. Accessory genitalic process of tergum VI curved to right at approximately 55 degree at proximal third, angled again at approximately 120 degree almost at mid-length ( Fig. 2C ). Medial lobes of tergum VIII (pseudoparameres) symmetrical, posterolateral corner narrowly rounded, posteromesal corners broadly rounded, posterior margin slightly concave medially ( Fig. 2D ). Phallosoma elongate, linear, slender, tapering dorsoapically; endosomal sclerites knob-like apically, with conspicuous denticles; right sclerite extending basally further than left sclerite ( Fig. 2E ). Parameres symmetrical, almost as long as maximum width, mesal margin convex. 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. 2F ).

Diagnosis. This species can be distinguished from the other three in this section by the female SGP with a rounded lateral lobe at mid-length on the left margin and symmetrical, digitate posterolateral corners ( Fig. 2B ). Additionally, the male AGP tapers distally to a pointed and anterolaterally directed apex ( Fig. 2C ) and the pseudoparamere posterolateral corners are narrowly rounded ( Fig. 2D ).

Comparative notes. Ambrysus cosmius La Rivers exhibits a generally similar SGP to that of A. schuhi Reynoso & Sites and A. variegatus Usinger ; however, its posterolateral corners are symmetrical and digitate, whereas those of A. variegatus are subtriangular and those of A. schuhi are asymmetrical. Although the morphology of the male endosomal sclerites is similar among these three species, the denticles in A. cosmius are more conspicuous. The anterolaterally directed apex of the male AGP is a unique condition within the signoreti complex; in all other species the apex is, at most, laterally directed.

Discussion. This species measures 12.12–14.37 mm in length and 8.12–9.37 mm in width.Many of the specimens in the type series were collected by Usinger and Hinton in their trip to central Mexico during the spring and summer of 1933. At that time, taxonomic knowledge of the genus was inadequate, resulting in the misidentification of some of these specimens as representatives of A. signoreti (see Additional material examined section). According to La Rivers (1953), this misconception remained until Usinger was able to examine the type of A. signoreti in the Swedish Museum of Natural History. In the original description, La Rivers (1953) reported A. cosmius from the states of Guerrero, México, Morelos, and Oaxaca. During examination of specimens at the EMEC, we found two females from Michoacán, which were positively identified as belonging to A. cosmius . These two specimens were originally labeled by La Rivers as paratypes of A. cosmius , but were not reported in the original description or any subsequent publication (see Additional material examined section).

Variation. Some females can exhibit the lobe on the left margin of the SGP narrowly rounded, giving the appearance of a "pointed" lobe. Also, the small lobe on right margin can be absent. Males can have the AGP laterally directed.

Type locality. Mexico: Estado de México: Mpio. Tejupilco, Tejupilco.

Repository. Male holotype (Fig. 3) is housed at the CAS.

Published records: Mexico: Estado de México, Guerrero, Morelos, Oaxaca ( La Rivers 1953, Davis 1986, Reynoso-Velasco & Sites 2019b).

New records: Mexico: Jalisco, Michoacán, Puebla, Veracruz .

Distribution. This species is exclusively distributed in Mexico, in the south-central part of the country ( Fig. 4 ), with the majority of sites located within the Balsas Basin biogeographic province. All the localities are at an elevation below 2,000 meters, with the majority between 500–1,800 meters. Outside the limits of the Balsas Basin, the species is predominantly distributed in the Sierra Madre del Sur biogeographic province, with localities in its central Michoacán and eastern Oaxaca Highlands districts. A single locality from Guerrero is in the Pacific Lowlands province and another from Oaxaca is in the Veracruzan province.

Type material examined. HOLOTYPE ♂ (by original designation). MEXICO: ESTADO DE MÉXICO: [Mpio. Tejupilco], Tejupilco, Temescaltepec [District of Temascaltepec], 19-VI-1933 / H.E. Hinton & R.L. Usinger collectors / Ambrysus cosmius La Rivers HOLOTYPE / Ambrysus cosmius La Rivers determined by Ira La Rivers '50 / California Academy of Sciences Type No. 10056 . PARATYPES: same data as holotype (2♀ CAS) ; same but 15-VI-1933 / Ambrysus cosmius La Rivers ALLOTYPE (1♀ CAS). GUERRERO: [Mpio. Chilapa de Álvarez], Chilapa , 29-X-1930, Prof. L Schultze / Ambrysus cosmius La Rivers Paratype (1♀ EMEC; 2♂ USNM); [Mpio. Tecpan de Galeana], Tecpan , 02-IV-1930, Prof. L Schultze / Ambrysus cosmius La Rivers Paratype (2♂, 3♀ SEMC) ; same but / Ira La Rivers Collection bequeathed to the California Academy of Sciences - 1978 (1♂ CAS; 1♀ CNIN) . MORELOS: 14-VII-1936, H.D. Thomas / Ambrysus cosmius La Rivers Paratype (1♂, 1♀ SEMC) ; same but / Ira La Rivers Collection bequeathed to the California Academy of Sciences - 1978 (1♀ CAS) ; [Mpio. Temixco], Acatlipa, km 88 on Hwy Mexico City-Acapulco / 06-V-1945, J.G. Shaw / Ambrysus cosmius La Rivers Paratype (1♀ EMEC) ; same but / Ambrysus cosmius La Rivers determined by Ira La Rivers '50 / Ira La Rivers Collection bequeathed to the California Academy of Sciences - 1978 (1♀ CAS) . OAXACA: Oaxaca , 25-VIII-1937, H.D. Thomas / Ambrysus cosmius La Rivers Paratype (1♀ SEMC) .

Additional material examined. MEXICO: ESTADO DE MÉXICO: Mpio. Amatepec, Río San Felipe at Las Adjuntas , 20-IV-2004, R. Novelo coll. (1♂, 3♀ IEXA) ; same but 05-V-2008, R. Novelo & K. Cuevas colls. (2♂, 5♀ IEXA) ; Mpio. Amatepec, Río San Felipe at San Felipe de Jesús , [approx. 18.799 2, -100.1639], 1,000 m, 20-IV-2004, R. Novelo coll. (1♀ IEXA) ; [Mpio. Amatepec], Rio San Felipe at San Felipe de Jesús , 20-IV-2004, 3,280' (1♂ EMEC) ; same but / William D. Shepard, leg. (2♂ EMEC) ; Mpio. Santo Tomás, [Río Tilastoc at] Santa Bárbara , 19º10'29.4''N, 100º17'20.4''W, 1,051 m, 20-XII-2012, L-1463, Reynoso-Velasco coll. (1♂ UMC) ; [Mpio. Tejupilco], Tejupilco, Temescaltepec [District of Temascaltepec], 15-VI-1933 / H.E. Hinton & R.L. Usinger collectors (1♂, 3♀ EMEC) ; same but Ira La Rivers Collection bequeathed to the California Academy of Sciences - 1978 (1♂ CAS) ; [Mpio. Tejupilco], Tejupilco, Temescaltepec [District of Temascaltepec], 19-VI-1933 / H.E. Hinton & R.L. Usinger collectors (2♂ EMEC) ; same but / Ambrysus signoreti Stål (1♀ EMEC) ; [Mpio. Tejupilco], Tejupilco, Temescaltepec [District of Temascaltepec], 21-VI-1933 / H.E. Hinton & R.L. Usinger collectors (1♀ EMEC) ; same but / exch. @ RLU 1968 / Ambrysus signoreti Stål det. R.L. Usinger / C.J. Drake Accession (1♀ USNM) ; [Mpio. Tejupilco], Tejupilco, Temescaltepec [District of Temascaltepec], 13-VII-1932 [1933] / H.E. Hinton & R.L. Usinger collectors (1♀ EMEC) ; same but / Ira La Rivers Collection bequeathed to the California Academy of Sciences - 1978 (1♀ CAS) ; [Mpio. Tejupilco], Tejupilco, Temescaltepec [District of Temascaltepec], VII-1934 / H.E. Hinton (2♂, 2♀ EMEC) ; Temascaltepec, 11-VII-1933, Robert L. Usinger, Cal.Acad.Sci.Coll. / Ira La Rivers Collection bequeathed to the California Academy of Sciences - 1978 (1♂, 1♀ CAS) ; same but no date, #880, R.L. Usinger, H.E. Hinton (1♂, 3♀ CAS) . GUERRERO: Mpio. Teloloapan, [Arroyo El Naranjo] at km 20 on carr. Teloloapan-Apaxtla de Castrejón, nr. Tepozanalquillo , 18º14'26.8''N, 99º54'51''W, 1083 m, 29-XII-2012, L-1497, Reynoso-Velasco coll. (1♂ IEXA) ; Mpio. Teloloapan, Río Oxtotitlán at Oxtotitlán , 18º11'35.7''N, 99º56'24.3''W, 1009 m, 29-XII-2012, L-1498, Reynoso-Velasco coll. (2♂, 1♀ IEXA) ; Mpio. Tepecoacuilco, [Río Atoyac at San Agustín] Oapan , 17º57'10.66''N, 99º27'38.8''W, 496 m, J. Amith coll. (1♀ UMC) . JALISCO: [Mpio Tuxpan], nr Atentique [Atenquique], CL740, 12-VI-1975, J.T. Polhemus / J.C. Drake Accession (1♀ USNM) . MICHOACÁN: [Mpio Aguililla, Río Aguililla at] Aguililla , [approx. 18.728 5, -102.7934], 03-IV-2005, R. Novelo coll. (1♂, 1♀ UMC) ; same but 02-X-2005, J.A. Gómez coll. (2♀ IEXA) ; [Mpio. Chinicuila, Río La Tortuga at] Villa Victoria , [approx. 18.751 0, -103.3600], 17-V-2002, R. Novelo coll. (1♀ UMC) ; Mpio. Coalcomán, La Chichihua , [approx. 18º44'36''N, 103º13'1.39''W], 10-VII-2005, R. Novelo & J.A. Gómez colls. (1♀ IEXA) ; [Mpio. Tuxpan], 5 mi N of Tuxpan, 16-VII-1953, 5,500 ft / Univ. Kans. Mex. Expedition / Slesnick Field N0. 48 / Ambrysus cosmius La Rivers 1953 (Ira La Rivers) / Ira La Rivers Collection bequeathed to the California Academy of Sciences - 1978 (1♀ CAS); Mpio. Tuzantla, Río Tuzantla at Tuzantla , 19º13'18.1''N, 100º34'05.5''W, 593 m, 21-XII-2012, L-1470, Reynoso-Velasco coll. (1♂ IEXA); [Mpio. Tzitzio], near Chinapa , 05-IX-1938 / Ambrysus cosmius Paratype (2♀ SEMC) [unpublished paratypes]. MORELOS: Mpio. Amacuzac, Río Amacuzac 1.6 km S (on dirt road) of km 50 carr. MEX 95 Cuernavaca-Taxco , 18º35'48.05''N, 99º23'57.88''W, 917 m, 04-I-2017, L-1990, Reynoso-Velasco coll. (2♀ IEXA) ; Mpio. Jojutla, Río Amacuzac at Tehuiztla , 18º33'45.2''N, 99º16'51.3''W, 853 m, 28-IV-2011, L-1308 Reynoso-Velasco coll. (4♂, 1♀ UMC) ; same but 18º32'47.9''N, 99º16'03.6''W, 854 m, L-1309 (1♂, 3♀ UMC) ; Mpio. Xochitepec, [Río Cuentepec at] Balneario Palo Bolero , [approx. 18.766 8, -99.2393], 07-VII-1987, R. Novelo coll. (1♂, 2♀ IEXA) ; Mpio. Xochitepec, Río Sabinos ( Cuentepec ) at Jardines de Xochitepec , [approx. 18.778 9, -99.2439], 24-IX-1998, R. Novelo coll. (1♂, 2♀ IEXA) ; same but 05-IV-2002, (3♀ IEXA) ; same but 24-IV-2003 (1♂, 2♀ IEXA) . OAXACA: Mpio. Putla Villa de Guerrero, Putla, [Río Cuchara] at Pte. La Cuchara , 17º01'07''N, 97º55'11.8''W, 711 m, 30-V-2012, L-1396, ReynosoVelasco coll. (2♂, 1♀ UMC) ; same but [ Río Cuchara at] 17º02'21.5''N, 97º54'42.9''W, 767 m, L-1397 (1♂ UMC) ; Mpio. San Antonio Nanahuatípam, Río Salado at San Antonio Nanahuatípam, 18°07'59.4''N, 97°07'42.6''W, 790 m, 24-III-2015, L-1877, Reynoso-Velasco, Sites, Shepard, & Barr colls. (4♂, 10♀ IEXA) ; [Mpio. San Antonio Nanahuatípam], Río Saldo at [San Gabriel] Casa Blanca , [approx. 18.155 1, -97.1371], 01-III-1976, R.R. & F.H. Miller, M76-41 (1♀ UMMZ) ; Mpio. San Felipe Jalapa de Díaz, Río Sto. Domingo at Sto. Domingo , 18°02'15.9''N, 96°32'57.2''W, 100 m, 25-IV-2015, L-1881, Reynoso-Velasco, Sites, Shepard & Barr colls. (5♂, 4♀ IEXA) ; [Mpio. San Juan Bautista Cuicatlán], Río Las Huertas [Las Vueltas] at Santiago Dominguillo, 12-VII-1996, R. Barba & A. Rojas colls. / Colección del Instituto de Biología , UNAM. México D.F. (2♂, 3♀ UMC) ; Mpio. San Juan Bautista Cuicatlán, [Río Las Vueltas at] Santiago Dominguillo , 17º38'46''N, 96º54'36.7''W, 726 m, 01-VI-2012, L-1405, Reynoso-Velasco coll. (1♂, 2♀ CNIN; 4♂, 9♀ IEXA; 18♂, 16♀ UMC) ; [Mpio. San Pedro Totolápam], Rio Grande [at] Totolapan [Totolápam], CL1063, 29-IV-1964, J.T. & M.S. Polhemus / Ambrysus cosmius '67 La Riv. Det. J.T. Polhemus (1♂ EMEC) ; same but / C.J. Drake Accession (4♂, 3♀ USNM) ; [Mpio. Santa María Tecomavaca, Arroyo Los Cués at] San Juan de Los Cués, 14-VI-1984, Mario García coll. / Colección del Instituto de Biología , UNAM. México D.F. / C.J. Drake Accession (1♀ USNM) ; same but / J.T. Polhemus Collection 2014 (1♀ USNM) ; [Mpio. Santa María Tecomavaca], Río Salado [at Pte. El Saldo], 16 km S of San Juan de Los Cués on carr. MEX 135 Tehuacán-San Francisco Telixtlahuaca , 17º55'50.5''N, 97º00'04.2''W, 544 m, 01-VI-2014, L-1407, Reynoso-Velasco coll. (2♂, 2♀ CNIN; 7♂, 15♀ IEXA; 2♀ UMC) ; Mpio. Valerio Trujano, Río Grande at Pte. Río Grande , km 124 carr. MEX 135 Tehuacán-San Francisco Telixtlahuaca on jct. to Tomellín , 17º45'25''N, 96º56'59.1''W, 607 m, 01-VI-2012, L-1406, Reynoso-Velasco coll. (3♂, 2♀ CNIN; 21♂, 13♀ IEXA; 2♂, 2♀ NHMW; 12♂, 13♀ UMC) ; San Cristobal, 17-VI-84, H. Velazco coll. / Colección del Instituto de Biología , UNAM. México D.F. (1♀ UMC) ; 18 mi NW El Camarón, 20-VIII-1959, A.E. Menke coll. / Ambrysus cosmius La Rivers 1953 (Ira La Rivers) / Ira La Rivers Collection bequeathed to the California Academy of Sciences - 1978 (2♂, 2♀ CAS; 1♀ CNIN) ; 25 mi S of Mitla , 04-I-1956, J.C. Schaffner / Ambrysus cosmius '67 LaR det. J.T. Polhemus / C.J. Drake Accession (1♀ USNM) . PUEBLA: Mpio. Coxcatlán, [Río Tepazalco at] La Estación , 5 km SW of Coxcatlán, 18°15'07.3''N, 97°11'24.5''W, 950 m, 24-III-2015, L-1876, Reynoso-Velasco, Sites, Shepard, & Barr colls. (2♀ IEXA) . VERACRUZ: [Mpio. Fortín], Río Metalac [Metlac] 3 mi N of El Fortín [Fortín de Las Flores, approx. 18.931 2, -97.0211], 2-VII-1955, R.B. & J.M. Selander (1♂, 2♀ BYU) .

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 1. Representative female subgenital plate of each of three sections in the Ambrysus signoreti Stål complex (terminal abdominal segments removed; solid line indicates level of posterolateral corners and dashed line level of central lobe). (A) posterolateral corners extending posteriorly further than central lobe in Ambrysus cosmius La Rivers, (B) central lobe extending posteriorly further than posterolateral corners in A. inflatus La Rivers, (C) posterolateral corners and central lobe almost at the same level in A. signoreti Stål. sgp = subgenital plate.

FIGURE 2. Structures of Ambrysus cosmius La Rivers. (A) dorsal habitus of male (yellow arrow indicates light mark at lateral margin and white arrows light mark along posterolateral angle of corium), (B) sternum VI and subgenital plate of female (terminal abdominal segments removed), (C) 6th and 7th abdominal terga of male (inset indicates angles measured on the accessory genitalic process), (D) 8th abdominal tergum of male, (E) ventral surface of male phallosoma, (F) genital capsule of male (phallosoma removed). agp = accessory genitalic process, cl = central lobe, 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 4. Distribution of Ambrysus cosmius La Rivers.

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