Ambrysus altiplanus Reynoso

Reynoso-Velasco, Daniel & Sites, Robert W., 2025, Revision of the Ambrysus signoreti Stål species complex (Heteroptera: Naucoridae: Ambrysinae). Section 3., Zootaxa 5735 (1), pp. 1-66 : 9-11

Ambrysus altiplanus Reynoso

( Figs. 2–3 )

Ambrysus altiplanus Reynoso in Reynoso-Velasco 2021a: Zootaxa, 5005: 305–310 (original description).

Diagnosis. This species can be distinguished from others in this section by the symmetrical female SGP with a small and rounded lateral lobe on each margin and inconspicuous apical lobes. Additionally, the posterolateral corners are short and pointed and the central lobe is shallowly concave medially, giving the appearance of a truncate lobe ( Fig. 2B ). Also, the male phallosoma presents the endosoma apically sclerotized on the left side and lobe-shaped ( Fig. 2E black arrow) and both endosomal sclerites knob-like with conspicuous denticles ( Fig. 2E ).

Comparative notes. Ambrysus sonorensis Usinger is the only other species in this section with low and inconspicuous apical lobes on the female SGP; nonetheless, the posterior margin of the SGP in A. sonorensis is different because the rounded posterolateral corners and the central lobe are poorly developed, in some cases inconspicuous (truncate posterior margin). Females of A. dyticus La Rivers , also in this section, exhibit the SGP with apical lobes as well, but these are conspicuous and pointed. The condition of the sclerotized, lobe-shaped endosoma of A. altiplanus Reynoso is similar to the digitate endosoma of A. inecol Reynoso and A. magniceps La Rivers.

Discussion. This species measures 12.64–14.00 in length and 7.88–8.19 in width.Although there is a superficial resemblance between A. altiplanus and A. sonorensis , the similarity of the male AGP ( Fig. 2C ), pseudoparameres ( Fig. 2D ), and endosoma suggests a closer relationship with A. inecol and A. magniceps . Relationship with the latter species is supported by recent evidence based on molecular data ( Sites 2022).

Variation. Some females exhibit the lateral lobe on the left margin of the SGP narrowly rounded or pointed.

Type locality. Mexico: Durango: Mpio. Nombre de Dios, Río Mezquital at Puente Melones , km 239 carr. MEX45 Vicente Guerrero-Durango , 23°52’17.3’’N, 104°16’04.7’’W .

Repository. Female holotype ( Fig. 2A ) is housed at the IEXA.

Published records: MEXICO: Chihuahua, Durango, Guanajuato, Hidalgo, Jalisco, Querétaro, San Luis Potosí, Zacatecas ( Reynoso-Velasco 2021a) .

Distribution. Ambrysus altiplanus is distributed in north-central Mexico ( Fig. 3 ) at elevations of 1500–2100 meters. The range includes localities in the western and southern areas of the Central Mexican Plateau, in the Chihuahuan Desert biogeographic province.

Type material examined. HOLOTYPE ♀ (by original designation). MEXICO: Durango: Mpio. Nombre de Dios, km239 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 Bernardo, 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 [most likely close to 20º34’47.54’’N, 99º37’42.99’’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) . Querétaro: 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 2. Structures of Ambrysus altiplanus Reynoso. (A) Dorsal habitus of female holotype, (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 (black arrow indicates lobe-shaped portion of endosoma). agp = accessory genitalic process, al = apical lobe, cl = central lobe, les = left endosomal sclerite, ll = lateral lobe, plc = posterolateral corner, pmc = posteromesal corner, pp = pseudoparamere, res = right endosomal sclerite, sgp = subgenital plate.

FIGURE 3. Distribution of Ambrysus altiplanus Reynoso.