Ambrysus hydor La Rivers, 1953

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 : 21-24

Ambrysus hydor La Rivers

( Figs. 12–14 )

Ambrysus hydor La Rivers 1953a : Univ. Kans. Sci. Bull., 35: 1323–1325 (original description).

Supplemental description. Female. Mediosternite VII (SGP) symmetrical; margins with pointed to right-angled lateral lobes at mid-length; posterolateral corners small, pointed; central lobe indistinctly concave medially, almost at same level as posterolateral corners ( Fig. 12B ).

Male. Accessory genitalic process of tergum VI (AGP) curved to right at approximately 30 degrees at proximal third, angled again at approximately 80 degrees at distal third ( Fig. 12C ) Medial lobes of tergum VIII (pseudoparameres) symmetrical, posterolateral and posteromesal corners broadly rounded, posterior margin shallowly concave medially ( Fig. 12D ). Phallosoma elongate, linear, slender, tapering dorsoapically; endosomal sclerites knob-like, with small denticles ( Fig. 12E ). Parameres symmetrical, slightly longer than 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. 12F ).

Diagnosis. Ambrysus hydor La Rivers can be distinguished from other species in the section by the symmetrical SGP with pointed to right-angled lateral lobes at mid-length of each margin. Additionally, the posterolateral corners are small and pointed and the central lobe is indistinctly concave medially. Also, the male phallosoma presents both endosomal sclerites knob-like with small denticles.

Comparative notes. This species is superficially most similar to A. occidentalis and A. scalenus because of the overall dorsal coloration, including the light-brown to reddish with dark-brown spots markings on the corium. Nevertheless, the “more” elliptical body form and particular shapes of markings on the corium give this species a closer resemblance to A. occidentalis than to A. scalenus , to the point that the two species are almost superficially indistinguishable (compare Fig. 12A to Fig. 20A ). The main difference between the two species is that the posterior margin of the female SGP is almost straight in A. occidentalis (central lobe low and at same level as the posterolateral corners), whereas the central lobe in A. hydor extends slightly further posteriorly (not to the point to consider this species a member of Section 2 of the complex, where the central lobe clearly extends posteriorly further than the posterolateral corners). Additionally, males of this species exhibit pseudoparameres with posterolateral corners broadly rounded, whereas males of A. occidentalis have these corners narrowly rounded. The spinose posterolateral corners of abdominal segments III–V in males and females of A. hydor are generally more developed (robust).

Discussion. This species measures 10.62–12.50 in length and 7.25–8.50 in width. Although different aspects of the morphology of this species are similar to those of A. occidentalis , the recent phylogenetic analysis ( Reynoso-Velasco & Sites 2021) suggests that A. hydor is more closely related to A. henryi Reynoso & Sites (Section 2), and together these two species are sister to A. occidentalis .

La Rivers (1953a) reported the female allotype to be a specimen from Jalisco ( Unión de Tula), which is housed at the SEMC. In addition to the Jalisco specimen, we also examined another allotype-label bearing specimen, which is a female from Estado de México ( Tejupilco ) housed at the CAS; most probably La Rivers misplaced the allotype label on this latter specimen. Also , in the original description, La Rivers reported an unspecified number of paratypes collected in Tejupilco on 19 June 1933. We examined three specimens ( 1♀ CAS; 1♂, 1♀ EMEC) bearing La Rivers’ A. hydor paratype labels from this locality, but only the female in the CAS was collected on the date reported in the original description; however, we consider the specimens in the EMEC to be valid paratypes as they have La Rivers’ handwritten paratype labels and because the only information that differs from that in the original description is the day the specimens were collected at the reported locality (see Type material examined section). Contrarily, a female in the CAS from the state of Sinaloa (Mazatlán) and a female in the SEMC from the state of Aguascalientes, both specimens bearing La Rivers’ A. hydor paratype labels, are herein not considered as valid paratypes, because neither the locality nor the state was reported in the original description (see Additional material examined section) .

An early concept of the species boundaries in the genus Ambrysus , as well as the variation on the shape of the female SGP of this species and A. occidentalis (see Variation sections of both species) and the almost identical dorsal appearance of the two species most likely resulted in the identification by DRV of some specimens deposited in different collections as belonging to A. hydor when they were actually members of A. occidentalis , or vice versa; consequently, further examination that also considers important features of the males is necessary to clearly establish whether those specimens belong to A. hydor or A. occidentalis . These specimens, mostly from northwestern Mexico where the species distributions overlap, were not included in this study (to the best of our knowledge).

Variation. Some females exhibit the SGP with the lateral lobes more developed, posteriorly directed, and clearly pointed. The posterolateral corners can be small and rounded or inconspicuous. In some cases, the central lobe is not concave medially. Also, females can present an asymmetrical SGP with a slightly smaller lateral lobe on the right margin or the left lateral lobe pointed and that on the right margin right-angled. Some males exhibit the left endosomal sclerite less developed, thereby reducing its knob-like shape.

Type locality. Mexico: Morelos : Río Amacuzac at kilometer 133 south of Mexico City .

Repository. Male holotype ( Fig. 13A ) is housed at the SEMC .

Published records: MEXICO: Estado de México, Guerrero, Jalisco, Michoacán, Morelos ( La Rivers 1953a; Reynoso-Velasco & Sites 2016a, 2018a, 2018b). The record from Guerrero reported in the original description ( La Rivers 1953a) was based on paratypes with label data indicating they were collected by H.D. Thomas at La Sabana and Puente de Ixtla, Guerrero. In fact, the town of Puente de Ixtla and the homonymous municipality are political and administrative divisions of the contiguous state of Morelos; thus, this particular record is inaccurate.

New records: Mexico: Aguascalientes, Colima, Nayarit, Oaxaca, Puebla, Sinaloa, Sonora .

Distribution. Ambrysus hydor is distributed exclusively in Mexico, along the central and northwestern parts of the country ( Fig. 14 ). This species exhibits a predominantly neotropical distribution that includes watercourses below 2,000 meters, with the majority of records within the Balsas Basin and the northern section of the Pacific Lowlands biogeographic provinces.

Type material examined. HOLOTYPE ♂ (by original designation). MEXICO: Morelos: Río Amacuzac, Morelos, kil. 133 S Mex. City, 14-X-[19]36, H.D. Thomas / Ambrysus hydor La Rivers HOLOTYPE. PARATYPES: Estado de México: Tejupilco, Mex. Temescaltepec [Temascaltepec], 15-VI-[19]33, H.E. Hinton & R.L. Usinger colls. / Ambrysus hydor La Rivers Allotype [incorrectly labeled as allotype; in the original description the allotype was reported to be a specimen from Jalisco and housed at the SEMC] / Ira La Rivers Collection Bequeathed to the California Academy of Sciences - 1978 / Paratype Ambrysus hydor La Rivers det. [in] 1970 by Vincent Lee / Univ. of Kansas has the published allotype, 06-XII-[19]78, V.F. Lee ( 1♀ CAS); Tejupilco, Mex. Temescaltepec [Temascaltepec], 21-VI-[19]33 / H.E. Hinton & R.L. Usinger colls. / Ambrysus hydor La Rivers Paratype / Ambrysus hydor La Rivers determined by Ira La Rivers 1948 ( 1♀ EMEC); same but 19-VI-[19]33 / 101 / to be compared with Ambrysus signoreti Stål #2 ( 1♂ EMEC); Tejupilco, Mex. Temescaltepec [Temascaltepec], 23-VI-[19]33 / H.E. Hinton & R.L. Usinger colls. / Ambrysus hydor La Rivers Paratype / Ira La Rivers Collection Bequeathed to the California Academy of Sciences - 1978 ( 1♀ CAS). Guerrero: La Sabana, kil. 226 S of Mex. City, 20-X- [19]36, H.D. Thomas coll. / Ambrysus hydor La Rivers Paratype ( 1♀ SEMC). Jalisco: [Mpio. Unión de Tula], Unión de Tula, 16-IX-[19]38, H.D. Thomas / Ambrysus hydor La Rivers Allotype ( 1♀ SEMC) [specimen reported as the allotype in the original description]; [Mpio. Unión de Tula], Unión de Tula, 16-IX-[19]38, H.D. Thomas / Ambrysus hydor La Rivers Paratype ( 1♀ SEMC). Michoacán: [Mpio.] Uruapan, El Sabino, 28-VII-1936, H.D. Thomas / Ambrysus hydor La Rivers Paratype ( 1♀ SEMC). Morelos: [Mpio. Puente de Ixtla], Puente de Ixtla, Gro. [ Morelos], 12-VII-[19]37, H.D. Thomas coll. / Ambrysus hydor La Rivers Paratype ( 1♀ EMEC; 1♀ SEMC); same but / donated to AMNH by J. T. Polhemus ( 1♀ USNM).

Additional material examined. MEXICO: Aguascalientes: 5 mi S of Aguascalientes, 16-VII-[19]34, Smith & Dunkle colls. / Ambrysus hydor La Rivers Paratype ( 1♀ SEMC) [locality not reported in the original description]. Colima: Mpio. Armería, Río Armería at Cofradía de Juárez (Periquillo), 3 km NE of Armería, 18°57’16.8’’N, 103°56’45.7’’W, 36 m, 24-VI-2013, L-1571, Reynoso-Velasco, D. coll. ( 2♂, 2♀ UMC); Mpio. Comala, Río Armería SE of Zacualpan, 19°19’38.8’’N, 103°48’50.1’’W, 461 m, 23-VI-2013, L-1568, Reynoso-Velasco, D. coll. ( 1♀ UMC); Mpio. Coquimatlán, Río Colima at Los Amiables, 19°09’48.9’’N, 103°50’06.9’’W, 288 m, 23-VI-2013, L-1570, Reynoso-Velasco, D. coll. ( 2♀ IEXA); Mpio. Piscila, Río Salado at Pte. El Salado, 19°11’39.8’’N, 103°41’37.9’’W, 371 m, 23-VI-2013, L-1567, Reynoso-Velasco, D. coll. ( 1♂, 2♀ IEXA; 3♂, 2♀ UMC). Estado de México: km 10 [carr.] Tejupilco-Temascaltepec, 20-X-1983, E. Barrera / Colección del Instituto de Biología, UNAM, México D.F. / C.J. Drake Accession ( 1♂ USNM); Mpio. Luvianos, Caja de Agua, 18º57’58’’N, 100º17’30.9’’W, 1079 m, L-1460, 20-XII-2012, Reynoso-Velasco, D. coll. ( 2♂ IEXA; 1♂, 1♀ UMC); Mpio. Santo Tomás de los Plátanos, Santa Bárbara, in front of Sta. Bárbara hydroelectric plant, 19º10’29.4’’N, 100º17’20.4’’W, 1051 m, L-1463, 20-XII-2012, Reynoso-Velasco, D. coll. ( 4♂, 9♀ UMC); Mpio. Tejupilco, Arroyo Paso de Vigas at Paso de Vigas, 18º53’32.6’’N, 100º13’57.0’’W, 1107 m, L-1459, 19-XII-2012, Reynoso-Velasco, D. coll. ( 1♀ IEXA; 2♂, 2♀ UMC); same but L-1909, 05-IV-2015, Reynoso, Sites, Shepard & Barr colls. ( 4♂, 2♀ IEXA); Mpio. Tejupilco,Río Bejucos at Bejucos, 700 m, 22-IV-2004, R.Novelo coll.( 1♂, 1♀ IEXA); Tejupilco,Mex.Temescaltepec [Temascaltepec], VII-1934 / H.E. Hinton ( 1♂ EMEC). Guerrero: km 154 carr. Iguala-Cd. Altamirano, 23-XI-1984, M. Vértiz coll. / Colección del Instituto de Biología, UNAM, México D.F. / C.J. Drake Accession ( 1♀ USNM); [Mpio. Acapulco], Acapulco, 14-VII-1937 / Ambrysus magniceps La Rivers det. J. R. Davis [19]95 ( 1♂ SEMC); Mpio. Atenango del Río, Río Amacuzac at Atenango del Río, 18º06’01.5’’N, 99º06’27.8’’W, 631 m, 30-XII-2012, L-1499, Reynoso-Velasco, D. coll. ( 2♂ UMC); [Mpio. Chilpancingo de los Bravo], Acahuizotla, 27-VI-1983, M. Marcía coll. / Colección del Instituto de Biología, UNAM, México D.F. / C.J. Drake Accession ( 1♀ USNM); Mpio. Copalillo, Río Balsas (Río Papalutla o Atoyac) at Papalutla, 18º01’27’’N, 98º54’09.3’’W, 627 m, L-1500, 30-XII-2012, Reynoso-Velasco, D. coll. ( 1♀ IEXA); Mpio. Coyuca de Catalán, carr. Zihuatanejo-Coyuca de Catalán, Río Los Placeres nr. Placeres del Oro, 18º12’50.8’’N, 100º53’23’’W, 382 m, L-1495, 28-XII-2012, Reynoso-Velasco, D. coll. ( 1♂, 2♀ IEXA; 3♂, 4♀ UMC); Mpio. Coyuca de Catalán, Río Los Nopales at Las Cruces, 18º14’49.6’’N, 100º46’08.9’’W, 314 m, L-1496, 28-XII-2012, Reynoso-Velasco, D. coll. ( 1♀ UMC); [Mpio. Eduardo Neri], Río Mexcala [Mezcala] 31 mi S of Iguala, 26-IV-1964, CL1040, J. T. & M.S. Polhemus colls. / Ambrysus lunatus lunatus Usinger det. J. T. Polhemus ( 2♂, 1♀ SEMC); [Mpio. Eduardo Neri], Río Mexcala [Mezcala] 31 mi S of Iguala, 26- IV-1964, CL1040, J. T. & M.S. Polhemus colls. / C.J. Drake Accession ( 2♂, 6♀ USNM); same but / Ambrysus close to sonorensis det. J. T. Polhemus ( 1♂ USNM) [last nine specimens with author’s ( DRV) label inaccurately identifying them as A. occidentalis ]; Mpio. Teloloapan, [Arroyo El Naranjo] at km 20 carr. Teloloapan-Apaxtla de Castrejón, nr. Tepozanalquillo, 18º14’26.8’’N, 99º54’51’’W, 1083 m, L-1497, 29-XII-2012, Reynoso-Velasco, D. coll. ( 1♀ UMC); Mpio. Teloloapan, Río Oxtotitlán at Oxtotitlán, 18º11’35.7’’N, 99º56’24.3’’W, 1009 m, L-1498, 29-XII-2012, Reynoso-Velasco, D. coll. ( 3♂, 3♀ IEXA; 27♂, 10♀ UMC); Mpio. Tepecoacuilco, [San Agustín] Oapan, 18º01’36.2’’N, 99º27’23.6’’W [wrong GPS data], J. Amith coll. ( 2♂ UMC). Jalisco: Mpio.Atenguillo, El Bajío, km 55 carr. Mascota-Ayutla, ca. 2 km NW of Los Volcanes, 20°20’08.2’’N, 104°34’19.2’’W, 1509 m, 27-VI-2013, L-1581, Reynoso-Velasco, D. coll. ( 3♂, 3♀ UMC); Mpio. Atenguillo, Río Atenguillo at Los Volcanes, 20°19’16.5’’N, 104°31’41.1’’W, 1459 m, 27-VI-2013, L-1582, Reynoso-Velasco, D. coll. ( 1♀ UMC); Mpio. Jalostotitlán, Río Verde at San Nicolás de las Flores on carr. 215 Jalostotitlán-Teocaltiche, 21°17’32.7’’N, 102°33’15.4’’W, 1653 m, 28-VI-2013, L-1585, Reynoso-Velasco, D. coll. ( 18♂, 9♀ IEXA; 19♂, 22♀ UMC); [Mpio. La Huerta], Cuitzmala / 20-III-1975, H. Brailovsky coll. / Ambrysus hydor 1953 (Ira La Rivers) ( 1♀ CNIN); [Mpio. La Huerta], Estación de Biología Chamela, Cuitzmala, 11-I-1975, H. Brailovsky coll. / C.J. Drake Accession ( 1♂ USNM); [Mpio. La Huerta], Estación de Biología Chamela, Río Cuitzmala, 20-III-1975 / Ambrysus hydor 1953 (Ira La Rivers) ( 1♀ CNIN); same but Ambrysus hydor La Rivers det. H. Brailovsky A. ( 1♀ CNIN); [Mpio. La Huerta], Río Cuitzmala SE of Chamela, 06-I-2005, 180’ / William D. Shepard, leg. ( 1♂, 2♀ EMEC); Mpio. La Huerta, Río San Nicolás at Pte. San Nicolás, 19°39’20.8’’N, 105°10’49.3’’W, 11 m, L-1574, 25-VI-2013, Reynoso-Velasco, D. coll. ( 1♂ IEXA); Mpio. Puerto Vallarta, La Desembocada, 20°43’36.5’’N, 105°09’25.7’’W, 39 m, L-1577, 26-VI-2013, Reynoso-Velasco, D. coll. ( 1♀ UMC); Mpio. Puerto Vallarta, Las Palmas de Arriba, 20°49’31.3’’N, 105°05’25.3’’W, 120 m, L-1578, 26-VI-2013, Reynoso-Velasco, D. coll. ( 1♂, 2♀ UMC); Mpio. San Sebastian del Oeste, Arroyo Los Arrayanes at Pte. Los Arrayanes, 20°49’44.5’’N, 105°00’45.1’’W, 337 m, L-1579, 26-VI-2013, Reynoso-Velasco, D. coll. ( 55♂, 39♀ UMC); Mpio. San Sebastián del Oeste, km 57 carr. [544] San Sebastián-Puerto Vallarta, Ejido Soyután, 20º49.899’N, 105º00.649’W, 439 m, 09-IX-2014, Gómez, Smith & Novelo colls. ( 1♂, 1♀ IEXA); Mpio. Tomatlán, Río Tomatlán at Tomatlán, 19°56’41.4’’N, 105°14’36.1’’W, 27 m, L-1575, 25-VI-2013, Reynoso-Velasco, D. coll. ( 4♂, 4♀ IEXA; 6♂, 6♀ UMC); [Mpio. Tomatlán], Río Tomatlán 2 mi E of Tomatlán, 03-III-1957, M57-19, R. R. & M. Miller & W.P. Hudson ( 1♀ UMMZ); [Mpio. Unión de Tula], Unión de Tula, 16-IX-[19]38, H.D. Thomas coll. / Ambrysus scalenus Paratype [incorrect identification] ( 1♂ SEMC). Michoacán: Mpio. Aguililla, Aguililla, 20-II-2005, R. Novelo & J.A. Gómez colls. ( 2♂, 3♀ IEXA); same but 03-IV-2005, R. Novelo coll. ( 1♂, 1♀ UMC); same but al sur de Coalcomán, 06-VI-2005 ( 1♂, 1♀ IEXA); Mpio. Aquila, river at Pte. Ramal Aquila just SW of Aquila, 18º35’08.1’’N, 103º30’51.8’’W, 159 m, L-1487, 25-XII-2012, Reynoso-Velasco, D. coll. ( 1♂ UMC); Mpio. Buenavista, Buenavista Tomatlán, 19º12’57.8’’N, 102º34’30.2’’W, 440 m, 24-XII-2012, L-1481, Reynoso-Velasco, D. coll. ( 4♀ IEXA; 3♂, 1♀ UMC); Mpio. Carácuaro, Río San Diego at Carácuaro, 19º01’04.8’’N, 101º07’33.2’’W, 519 m, L-1473, 22-XII-2012, Reynoso-Velasco, D. coll. ( 2♂, 2♀ IEXA; 4♂, 4♀ UMC); Mpio. Chinicuila, Villa Victoria (arroyo), 740 m, 17-V-2002, R. Novelo coll. ( 1♀ IEXA); Mpio. La Huacana, Colonia Lázaro Cárdenas at La Huacana, 18º57’19’’N, 101º48’43.2’’ W, 458 m, L-1478, 23-XII-2012, Reynoso-Velasco, D. coll. ( 5♂, 2♀ IEXA; 12♂, 3♀ UMC); Mpio. Múgica, Pte. El Marquéz 5 km NE of Nueva Italia on carr. 37 Nueva Italia-Uruápan, 13-III-2004, R. Novelo coll. ( 1♂ IEXA); Mpio. Múgica, Río Tepalcatepec at Pte. Capiro, km 46 on carr. 37 Apatzingán- Arteaga, 3 km SW of Nuevo Capirio, 14-IX-2004, R. Novelo coll. ( 1♀ IEXA); Mpio. Nocupétaro, 4 km NW of Nocupétaro de Morelos, at Pte. Patambo, 19º03’34.6’’N, 101º11’45.4’’W, 622 m, L-1474, 22-XII-2012, Reynoso-Velasco, D. coll. ( 3♂, 2♀ IEXA; 8♂, 2♀ UMC); Mpio. Nocupétaro, San Antonio de la Huerta (Melchor Ocampo), under bridge, 19º02’ 04.4’’N, 101º15’07.9’’W, 624 m, L-1475, 22-XII-2012, Reynoso-Velasco, D. coll. ( 2♂ IEXA; 5♂, 1♀ UMC); Mpio. Parácuaro, Crucero Las Yeguas, Río El Orejón at Pte. El Orejón, 12-III-2004, R. Novelo coll. ( 2♂, 2♀ IEXA); Mpio. Parácuaro, Río Tepalcatepec at Las Yeguas, 18º53’42.1’’N, 102º17’00.3’’W, 189 m, L-1480, 24-XII-2012, Reynoso-Velasco, D. coll. ( 1♂, 1♀ IEXA; 3♂, 4♀ UMC); Mpio. Tacámbaro, Rió Frío ca. 18 km E of Tacámbaro, 19º12’50.4’’N, 101º20’47.1’’W, 1297 m, L-1476, 23-XII-2012, Reynoso-Velasco, D. coll. ( 2♂ UMC); Mpio. Tepalcatepec, Los Horcones, Pte. Pinolapa at km 31 carr. Tepalcatepec-Coalcomán, 19º00’31.3’’N, 103º01’25.6’’W, 554 m, L-1484, 25-XII-2012, Reynoso-Velasco, D. coll. ( 1♂, 1♀ IEXA; 4♂, 2♀ UMC); Mpio. Tepalcatepec, Río Pinolapa (orilla), 26-IX-2005, R. Novelo & J.A. Gómez colls. ( 2♂, 1♀ IEXA); Mpio.Tepalcatepec, Río Pinolapa (puente) 2 km SW of Pinolapa, 16-V-2002, R. Novelo coll. ( 2♂, 2♀ IEXA); same but 28-III-2005 ( 1♂ IEXA); same but 10-VI-2006 ( 1♂, 3♀ IEXA); Mpio. Mpio. Tepalcatepec, Tepalcatepec, 19º11’47.3’’N, 102º50’44.9’’W, 371 m, L-1483, 24-XII-2012, Reynoso-Velasco, D. coll. ( 2♂, 2♀ IEXA; 7♂, 6♀ UMC); Mpio. Tiquicheo, Piedra China, Río Purengueo at Pte. Tiquicheo, 18º53’37.8’’N, 100º45’49’’W, 363 m, L-1472, 22-XII-2012, Reynoso-Velasco, D. coll. ( 3♂, 3♀ IEXA; 17♂, 10♀ UMC); Mpio. Tuzantla, Paso de Tierra Caliente, Las Garzas, 19º05’09.4’’N, 100º39’10.6’’W, 473 m, L-1471, 22-XII-2012, Reynoso-Velasco, D. coll. ( 4♂, 2♀ IEXA; 7♂, 5♀ UMC); Mpio. Tuzantla, Río Tuzantla at Tuzantla, 19º13’18.1’’N, 100º34’05.5’’W, 593 m, L-1470, 21-XII-2012, Reynoso-Velasco, D. coll. ( 1♀ IEXA; 2♀ UMC); [Mpio.] Uruapan, El Sabino, 28-VII-1936, H.D. Thomas / Ira La Rivers Collection Bequeathed to the California Academy of Sciences - 1978 ( 1♂ CAS); [Mpio.] Uruapan, El Sabino, 28-VII-1936, H.D. Thomas / Ambrysus scalenus La Rivers Paratype [incorrect identification] ( 2♂ SEMC); same but / Ira La Rivers Collection Bequeathed to the California Academy of Sciences - 1978 ( 1♀ CAS); Mpio. Zicuirán, Zicuirán, 18º53’01.4’’N, 101º58’34.3’’W, 216 m, L-1479, 23-XII-2012, Reynoso-Velasco, D. coll. ( 1♂, 1♀ UMC). Morelos: [Mpio. Amacuzac], Río Amacuzac [at] Huajintlán, 28-V-1983, D. Porras & L. Castrejón colls. / Colección del Instituto de Biología, UNAM, México D.F. ( 2♂, 3♀ CNIN); same but / Naucoridae Ambrysus sp. / C.J. Drake Accession ( 3♂, 1♀ USNM); Mpio.Amacuzac, Río Amacuzac at Pte. Huajintlán on carr. libre Cuernacava- Taxco, 18º36’35.56’’N, 99º25’40.38’’W, 931 m, 04-I-2017, L-1989, Reynoso-Velasco coll. ( 22♂, 23♀ IEXA); Mpio. Amacuzac, Río Amacuzac at 1.6 km on dirt road S of km 50 carr. Cuernavaca-Taxco, 18º35’48.05’’N, 99º23’57.88’’W, 917 m, 04-I-2017, L-1990, Reynoso-Velasco coll. ( 7♂, 5♀ IEXA); [Mpio. Amacuzac], 4 mi N of Amacuzac, CL1039, 25 Apr. 1964, J. T. & M.S. Polhemus colls. / C.J. Drake Accession ( 4♂, 4♀ USNM) [all eight specimens with author’s label inaccurately identifying them as A. occidentalis ]; [Mpio. Cuernavaca], Cuernavaca, VI-1943 / H.E. Hinton coll. ( 1♂ EMEC); Mpio. Jojutla, Río Amacuzac at San Rafael Vicente Aranda, 04-IV-2002, R. Novelo coll. ( 4♂, 4♀ IEXA); same but 900 m, 16-III-2001 ( 1♂, 4♀ IEXA); Mpio. Jojutla, Río Amacuzac at Tehuixtla, 18º33’45.2’’N, 99º16’51.3’’W, 853 m, 28-IV-2011, L-1308, Reynoso-Velasco, D. coll. ( 2♂, 3♀ IEXA; 8♂, 14♀ UMC); same but 18º33’41.8’’N, 99º16’46.1’’W, 856 m, 31-XII-2012, L-1502 ( 2♀ UMC); Mpio. Jojutla, [San Rafael] V [icente] Aranda, Río Amacuzac, 15-I-1983, V. García coll. ( 2♂, 2♀ UMC); Mpio. Jojutla, Tehuixtla, Río Amacuzac at Pte. ISSSTEHUIXTLA, 18º32’47.9’’N, 99º16’03.6’’W, 854 m, 28-IV-2011, L-1309, Reynoso-Velasco, D. coll. ( 10♂, 1♀ UMC); Mpio. Jonacatepec, estanque en Jonacatepec, 06-X-2001, R. Novelo coll. ( 1♂ IEXA); Mpio. Tlaquiltenango, El Astillero [also La Mezquitera], Río Cuautla, 850 m, 05-II-1983, I. Olivia coll., en orillas c/vegetación ( 4♂, 4♀ IEXA); Mpio. Yautepec, Oacalco (arroyo), 03-IV-2002, R. Novelo col. ( 2♀ IEXA); Mpio. Yautepec, Río Yautepec at Itzamatitlán, 17-III-2001, R. Novelo coll. ( 1♀ IEXA); 20 mi S of Cuernavaca, CL1047, 27 Apr. 1964, J. T. & M.S. Polhemus colls. / C.J. Drake Accession ( 1♂, 1♀ USNM) [both specimens with author’s label inaccurately identifying them as A. occidentalis ]. Nayarit: [Arroyo Refilión 29 km S of Tepic, at], El Refilio [Refilión], 2800’, CL729, 08-VI-1975, J. T. Polhemus coll. ( 1♂, 1♀ USNM); same but / C.J. Drake Accession ( 1♂ USNM); [last three specimens with author’s label inaccurately identifying them as A. occidentalis ]; Mpio. Acaponeta, Río Acaponeta at El Recodo, 22°31’31.9’’N, 105°20’37.3’’W, 34 m, 01-VII-2013, L-1601, Reynoso-Velasco, D. coll. ( 1♂, 3♀ IEXA; 7♂, 6♀ UMC); Mpio. Acaponeta, Río Acaponeta at La Guásima, 22°24’26.6’’N, 105°23’48.9’’W, 26 m, 02-VII-2013, L-1602, Reynoso-Velasco, D. coll. ( 1♂ UMC); Mpio. Acaponeta, Río Las Cañas at La Bayona, 22°31’15.8’’N, 105°26’44.4’’W, 20 m, 01-VII-2013, L-1600, Reynoso-Velasco, D. coll. ( 1♂, 2♀ IEXA; 2♂, 7♀ UMC); [Mpio. Ahuacatlán], Ahuacatlán, 12-VIII-1957, D. R. Lauck coll. / Ambrysus magniceps La Rivers 1953 (La Rivers) / C.J. Drake Accession ( 1♂, 1♀ USNM) [both specimens with author’s label inaccurately identifying them as A.occidentalis ];Mpio.Compostela,Las Piedras, Pte.Las Piedras,Río Las Piedras, 21°12’08.7’’N, 105°05’31.8’’W, 69 m, L-1654, 19-XII-2013, Reynoso-Velasco, D. coll. ( 7♂, 10♀ IEXA); Mpio. Compostela, Las Varas, Pte. Arroyo Seco, 21°11’15.2’’N, 105°07’21.7’’W, 39 m, L-1655, 19-XII-2013, Reynoso-Velasco, D. coll. ( 1♂, 2♀ IEXA); Mpio. Compostela, Río Compostela at Compostela, 21°14’01.4’’N, 104°53’38.6’’W, 853 m, L-1652, 18-XII-2013, Reynoso-Velasco, D. coll. ( 6♂, 8♀ IEXA); same but 21°14’01.4’’N, 104°54’22.9’’W, 840 m, L-1653 ( 1♀ IEXA); Mpio. Compostela, Río Huicila at Zacualpan, 21°15’04.1’’N, 105°09’30.6’’W, 20 m, 19-XII-2013, L-1656, Reynoso-Velasco, D. coll. ( 1♂ IEXA); [Mpio. Del Nayar], Jesús María, 26-VI-1955 / B. Malkin coll. ( 2♂, 3♀ EMEC); [Mpio. Del Nayar], Mesa del Nayar, 16–21-VII-[19]55, B. Malkin coll. ( 5♂ EMEC); [Mpio. Del Nayar], Playa de Golondrinas, Río Santiago, 27-V-1992, J. Bueno & R. Barba ( 8♂, 6♀ CNIN); [Mpio. Del Nayar], San Juan Peyotán, 01-VIII-[19]55, B. Malkin coll. ( 1♂, 3♀ EMEC); Mpio. Ruíz, Río San Pedro at Lomas de San Isidro, 3 km W of Vado San Pedro, 21°56’44.5’’N, 105°12’42.4’’W, 14 m, 02-VII-2013, L-1603, Reynoso-Velasco, D. coll. ( 1♂, 2♀ IEXA; 1♂, 4♀ UMC); Mpio. Ruíz, Río San Pedro at San Lorenzo, 21°57’04.1’’N, 105°04’28.3’’W, 23 m, L-1662, 20-XII-2013, Reynoso-Velasco, D. coll. ( 8♂, 3♀ IEXA); Mpio. Ruíz, Río San Pedro at Vado San Pedro, 21°57’01.7’’N, 105°10’45.0’’W, 13 m, 02-VII-2013, L-1604, Reynoso-Velasco, D. coll. ( 1♂, 1♀ UMC); [Mpio. San Blas], Aticama, CL727A, 07-VI-1975, J. T. Polhemus coll. / C.J. Drake Accession ( 5♂, 11♀ USNM); same but same but A. sonorensis? Usinger J.T.P. ‘99 ( 1♂ USNM) [all 17 specimens with author’s label inaccurately identifying them as A. occidentalis ]; Mpio. San Blas, El Palillo, Arroyo Palillo at Pte. Palillo, 21°38’27.1’’N, 105°08’30.8’’W, 43 m, L-1661, 20-XII-2013, Reynoso-Velasco, D. coll. ( 52♂, 22♀ IEXA); [Mpio. San Blas], Navarrette [Navarrete], 01-VII-[19]62 / A.E. Michelbacher coll. ( 1♂ EMEC); [Mpio. Santa Cruz de Miramar], Santa Cruz, 08-VI-1975, CL728, J. T. Polhemus coll. / C.J. Drake Accession ( 1♂ USNM) [specimen with author’s label inaccurately identifying them as A. occidentalis ]; Mpio. Santa María del Oro, El Ocotillo, 21°13’46.4’’N, 104°38’29.8’’W, 1176 m, 02-VII-2013, L-1605 Reynoso-Velasco, D. coll. ( 7♂, 8♀ IEXA; 13♂, 15♀ UMC). Oaxaca: Mpio.SanAntonio Nanahuatípam,Río Salado at SanAntonio Nanahuatípam, 18°07’59.4’’N, 97°07’42.6’’W, 790 m, L-1877, 24-III-2015, Reynoso, Sites, Shepard & Barr colls. ( 1♂, 3♀ IEXA); Mpio. San Sebastian Tecomaxtlahuaca, Tecomaxtlahuaca, Laguna Encantada, 17º21’57.5’’N, 98º01’13.3’’W, 1662 m, 30-V-2012, L-1399, Reynoso-Velasco, D. coll. ( 2♀ UMC). Puebla: Matamoros, 12 mi SE Puebla, 03-VII-1953, 3700 ft / Univ. Kans. Mex. Expedition / Slesnick Field No. 31 / Ira La Rivers Collection Bequeathed to the California Academy of Sciences - 1978 ( 1♂, 1♀, 1 indt. CAS); 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 Sites, Shepard & Barr colls. ( 1♀ IEXA); Mpio. Jolalpan, Río Nexapa at Jolalpan, 18º20’58.4’’N, 98º49’18.2’’W, 841 m, 30-XII-2012, L-1501, Reynoso-Velasco, D. coll. ( 2♂, 1♀ IEXA; 7♂, 1♀ UMC); [Mpio. Puebla], Puebla, 26-VI-1957, D. Lauck coll. / Ira La Rivers Collection Bequeathed to the California Academy of Sciences - 1978 ( 1♂, 2♀ CAS); [Mpio. Tehuitzingo], El Marquez, [Río Balsas/Atoyac at Puente El Marqués], CL1052, 28-IV1964, J. T. & M.S. Polhemus colls. / Ambrysus lundbladi Us. det. J. T. Polhemus / C.J. Drake Accession ( 1♀ USNM) [specimen with author’s label inaccurately identifying them as A. occidentalis ]; [Mpio. Tehuitzingo], Tehuitzingo, 10 mi SE Puebla, 03-VII-1953, 3900 ft / Univ. Kans. Mex. Expedition / Slesnick Field No. 32 / Ambrysus scalenus La Rivers 1953 (Ira La Rivers) ( 1♂ SEMC); same but / Ira La Rivers Collection Bequeathed to the California Academy of Sciences - 1978 ( 1♂ CAS); [Mpio Teziutlán], Teziutlán, 27-VII-1950, Drake & Hottes colls. / Ira La Rivers Collection Bequeathed to the California Academy of Sciences - 1978 ( 2♀ CAS). Sinaloa: [Mpio. Badiraguato], Río Badiraguato just upstream from village of Badiraguato, 06-III-1961, M61-15, R. R. Miller & H.L. Huddle colls. ( 1♂ UMMZ); [Mpio. Concordia], Arroyo El Zapotillo [at] 2 mi E of Concordia, 20-VII-1952, J.D. Lattin coll. / Ira La Rivers Collection Bequeathed to the California Academy of Sciences - 1978 ( 8♂, 4♀ CAS); [Mpio. Concordia], Concordia, 20-VII-1952, J. D. Lattini coll. / more in alcohol / Ira La Rivers Collection Bequeathed to the California Academy of Sciences - 1978 ( 1♂ CAS); Mpio. Concordia, Río Pánuco at Chupaderos, 23°21’49.2’’N, 105°57’10.3’’W, 244 m, L-1597, 30-VI-2013, Reynoso-Velasco, D. coll. ( 6♂, 6♀ UMC); Mpio. Cosalá, Río Conitaca ca. 27 km S of Cosalá, 24°13’26.6’’N, 106°44’37.9’’W, 169 m, L-1671, 22-XII-2013, Reynoso-Velasco, D. coll. ( 4♂, 4♀ IEXA); [Mpio. Culiacán], Culiacán, Río Culiacán / 25-VII-1952 / lunatus ? / Ira La Rivers Collection Bequeathed to the California Academy of Sciences - 1978 ( 1♀ CAS); [Mpio. Culiacán], Los Mayos, 24-VII-1952, J.D. Lattin coll., Cal.Acad.Sci. Coll. / Ira La Rivers Collection Bequeathed to the California Academy of Sciences - 1978 ( 1♂, 1♀ CAS); same but / lunatus ? ( 1♂ CAS); Mpio. Elota, Arroyo El Japuino at Pte. Los Barriles, 24°03’36.7’’N, 106°48’03.6’’W, 83 m, 22-XII-2013, L-1670, Reynoso-Velasco, D. coll. ( 2♀ IEXA); Mpio. Elota, Río Elota at Pte. Río Elota, 23°57’20.7’’N, 106°42’53.4’’W, 46 m, L-1669, 22-XII-2013, Reynoso-Velasco, D. coll. ( 16♂, 12♀ IEXA); Mpio. Guasave, Río Sinaloa at Estación Bamoa, 25°42’34.9’’N, 108°20’31.6’’W, 24 m, 23-XII-2013, L-1675, Reynoso-Velasco, D. coll. ( 1♂, 2♀ IEXA); [Mpio. Mazatlán], Mazatlán, 1934 / H.E. Hinton coll. ( 5♂, 1♀ EMEC); / Ira La Rivers Collection Bequeathed to the California Academy of Sciences ( 1♂, 1♀ CAS); [Mpio. Maztlán], Mazatlán, 25–26-V-1934 / H.E. Hinton coll. ( 2♂, 2♀ EMEC); same but / Ira La Rivers Collection Bequeathed to the California Academy of Sciences ( 1♀ CAS); same but / Ambrysus hydor La Rivers Paratype / an unpublished paratype det. [in] 1970 by Vincent F. Lee ( 1♂ CAS) [locality not reported in the original description]; Mpio. Mazatlán, Río Presidio at Siqueiros, 23°20’47.0’’N, 106°14’35.3’’W, 42 m, L-1664, 21-XII-2013, Reynoso-Velasco, D. coll. ( 4♂, 4♀ IEXA); Mpio. Mazatlán, Río Quelite at Pte. El Quelite, 23°31’19.5’’N, 106°29’52.9’’W, 12 m, L-1665, 21-XII-2013, Reynoso-Velasco, D. coll. ( 18♂, 20♀ IEXA); Mpio. Mazatlán, Villa Unión, Río Presidio at Pte. Presidio, 23°11’32.3’’N, 106°13’26.3’’W, 10 m, L-1598, 01-VII-2013, Reynoso-Velasco, D. coll. ( 18♂, 10♀ IEXA; 11♂, 11♀ UMC); [Mpio. Mazatlán], 28 mi N [of] Mazatlán, 23-VII-1967 / M. Wasbauer coll. ( 1♀ CSCA); Mpio. Mocorito, Rancho Viejo, Pte. Chico Ruíz, 25°07’24’’N, 107°45’29.9’’W, 59 m, L-1673, 23-XII-2013, Reynoso-Velasco, D. coll. ( 1♂ IEXA); Mpio. Mocorito, Río Evora at Mocorito, 25°28’55.1’’N, 107°54’37.6’’W, 75 m, L-1674, 23-XII-2013, Reynoso-Velasco, D. coll. ( 2♀ IEXA); Mpio. Rosarío, Río Baluarte at Pte. Baluarte, 23°00’26.0’’N, 105°51’04.5’’W, 24 m, 01-VII-2013, L-1599, Reynoso-Velasco, D. coll. ( 3♂, 1♀ UMC); Mpio. Rosario, Río Los Cedros at Matatán, 16 km W of El Rosario, 23°01’54.1’’N, 105°43’52.0’’W, 55 m, L-1663, 21- XII-2013, Reynoso-Velasco, D. coll. ( 3♂, 5♀ IEXA); [Mpio. Salvador Alvarado], Río Mocrito [Mocorito] just NW of Huamichie [Guamúchil], 03-II-1955, M55-4, Miller & Greenbank colls. ( 8♂, 5♀ UMMZ); Mpio. San Ignacio, Río Piaxtla at San Ignacio, 23°56’06.3’’N, 106°25’41.0’’W, 127 m, L-1666, 21-XII-2013, Reynoso-Velasco, D. coll. ( 25♂, 28♀ IEXA); same but 23°56’11.9’’N, 106°25’34.0’’W, 134 m, L-1667, 22-XII-2013 ( 20♂, 55♀ IEXA); Mpio. San Ignacio, Río Piaxtla at Pte. Río Piaxtla, 23°53’23.8’’N, 106°37’03.9’’W, 46 m, L-1668, 22-XII-2013, Reynoso-Velasco, D. coll. ( 1♂, 1♀ IEXA); Mpio. Sinaloa de Leyva,Arroyo Bacubirito at Bacubirito, 25°48’21.4’’N, 107°54’48.5’’W, 159 m, L-1677, 24-XII-2013, Reynoso-Velasco, D. coll. ( 1♂, 1♀ IEXA); [Mpio. Sinaloa de Leyva], Río Bacubirito near Bacubirito, 04-III-1962, M61-12, R. R. Miller & H.L. Huddle colls. ( 1♀ UMMZ); Mpio. Sinaloa de Leyva, Río Sinaloa at Burague, 25°49’25.4’’N, 107°57’49.4’’W, 140 m, L-1678, 24-XII-2013, Reynoso-Velasco, D. coll. ( 4♂, 5♀ IEXA); Mpio. Sinaloa de Leyva, Río Sinaloa at El Cajoncito, 25°52’41.1’’N, 107°56’50.8’’W, 119 m, 23-XII-2013, L-1676, Reynoso-Velasco, D. coll. ( 1♂ IEXA). Sonora: [Mpio. Álamos], Álamos, 29-VII-1953, F.S. Truxal coll. / Ira La Rivers Collection Bequeathed to the California Academy of Sciences - 1978 ( 1♀ UMC); same but 25-VII–07-VIII-1953 / Ambrysus hydor La Rivers 1953 (Ira La Rivers) ( 2♀ CAS); [Mpio. Álamos], Río Chuchuhaqui [Chuchujaqui] 7 mi S [of] Álamos, 25-VII–07-VIII-1953, Fred. S. Truxal coll. / Ambrysus hydor La Rivers 1953 (Ira La Rivers) / Ira La Rivers Collection Bequeathed to the California Academy of Sciences - 1978 ( 2♀ CAS).

Figures

FIGURE 12. Structures of Ambrysus hydor La Rivers. (A) Dorsal habitus of female, (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, (F) genital capsule of male (phallosoma removed).

FIGURE 13. Ambrysus hydor La Rivers. (A) Dorsal habitus, labels, and dissected last abdominal segments of male holotype, (B) subgenital plate and labels of female paratype (allotype).

FIGURE 14. Distribution of Ambrysus hydor La Rivers.

FIGURE 20. Structures of Ambrysus occidentalis La Rivers. (A) Dorsal habitus of female, (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, (F) genital capsule of male (phallosoma removed).