Ambrysus pygmaeus La Rivers
Creators: name: Reynoso-Velasco, Daniel
name: Sites, Robert W.
name: Novelo-Gutiérrez, Rodolfo
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Naucoridae
Ambrysus
Ambrysus pygmaeus

description: Ambrysus pygmaeus La Rivers
(Figs. 4, 9)
A. pygmaeus La Rivers 1953: Univ. Kans. Sci. Bull. 35: 1289–1290 (original description).
Diagnosis. This species can be distinguished from the others in this subgenus based on the shorter AGP that slightly curves to right at approximately 45 degrees and is slightly dilated distally (Fig. 9 B). The pseudoparameres are short, subrectangular, and asymmetrical with the left pseudoparamere slightly longer, with posterior margins straight, posterolateral corners rounded, and scattered fine setae (Fig. 9 C). The parameres are symmetrical, longer than wide, with the mesal margin straight, and a row of long setae emanating from the middle of the dorsal surface (Fig. 9 D). The left ventral lobe of the endosoma is lightly sclerotized (Fig. 9 E). The lateral margins of the SGP are narrowed subapically, giving it a characteristic bottleneck outline with an inverted V-shaped notch; the notch has two small pointed lobes (Fig. 9 F).
Discussion. This species was described based mainly on specimens collected in central Mexico. La Rivers (1951) noticed the prominent bulging eyes on the specimens of the type series and considered this feature diagnostic; however, this character is not particularly different from that exhibited by any other species in this subgenus in Mexico. La Rivers (1951) considered A. pygmaeus to be the most distinctive member of the oblongulus species complex, which he proposed but did not define. Later La Rivers and Nieser (1972) included four Central and South American species (A. bifidus, A. oblongulus, A. scolius, and A. stali) in the oblongulus species complex, but did not include A. pygmaeus as originally proposed (La Rivers 1951, 1953). The taxonomic status of the oblongulus species complex recently has been reviewed (Sites & Reynoso-Velasco 2015). Ambrysus pygmaeus was included in the subgenus Syncollus when the former division Coalescens was elevated to subgeneric rank (La Rivers 1965). The color pattern on this species is similar to A. circumcinctus with the hemelytra solid dark brown and embolia light brown anteriorly (Fig. 9 A). The triangular mark at the base of posterior margin of the corium is small and light brown to reddish brown.
Variation. La Rivers considered this a small species ranging from 7.0 to 7.5 mm in length, which is probably why he used pygmaeus as the specific epithet. Some specimens from southern Mexico (Oaxaca) are up to 8.4 mm in length. The small triangular mark at the base of posterior margin of corium is sometimes absent (Fig. 9 A). The two small pointed lobes in the notch on the posterior margin of the SGP can be inconspicuous.
Type locality. Mexico: Mexico: Mpio. Temascaltepec, Temascaltepec.
Repository. Holotype is housed at CAS.
Distribution. This species is distributed through the montane areas of the Mexican Transition Zone that includes the Sierra Madre Occidental (Durango), Sierra Madre del Sur (Oaxaca), and Transmexican Volcanic Belt (Mexico) biogeographic provinces. It is also present on the border of the Transmexican Volcanic Belt and the Balsas Basin biogeographic provinces (Morelos). All specimens examined were collected at elevations above 1500 meters, except those from Oaxaca (L-1396, L-1397; Fig. 4), which were 711 and 767 m, respectively. Herrera (2013) cited a record from Guatemala based on the California Academy of Sciences online database; however, we did not find these specimens in the collection at CAS.
Published records. Mexico: Estado de México (La Rivers, 1953, 1965, 1971).
Type material examined. HOLOTYPE ♂: [México: México: Mpio.] Temescaltepec [Temascaltepec], Mex. VI-5-33 / H. E. Hinton, R. L. Usinger Collectors / Ambrysus pygmaeus La Rivers HOLOTYPE / Ambrysus pygmaeus La Rivers determined by Ira La Rivers 1948 / California Academy of Sciences Type No. 10058. PARATYPES: Temescaltepec [Temascaltepec], Mex. VI-5-33 / H. E. Hinton, R. L. Usinger Collectors / Ambrysus pygmaeus La Rivers Paratype (2³, 2♀ EMEC); same but determined by Ira La Rivers '50 (1³ EMEC); Temescaltepec [Temascaltepec], Mex. VI-5-33 / H. E. Hinton, R. L. Usinger Collectors / Ambrysus pygmaeus La Rivers Paratype / 79 [without terminal abdominal segments] (1³ EMEC); same but 80 [without terminal abdominal segments] (1♂ EMEC). MORELOS: Cuernavaca, Mex, 1934 / H. E. Hinton / Ambrysus pygmaeus La Rivers PARATYPE (3³ EMEC; 1³, 1♀ SEMC).
Material examined. MÉXICO: DURANGO: La Michilía, Arroyo El Temazcal, 10-Diciembre-1987. R. Novelo col. (4³, 1♀ UMC); Res. Biósfera de Michilía, Arroyo el Temascal, 1-VII-1985, 2260 msnm, C. Castillo, P. Reyes (1³, 2♀ CNIN); Res. Biósfera de Michilía, Est. Piedra Herrada, 1-VII-1985, 2350 msnm, C. Castillo, P. Reyes (1♀ CNIN); same but 2-VII-1985, 2260 msnm (1♀ CNIN). MÉXICO: Temescaltepec [Temascaltepec], Mex. VI-5-33 / H. E. Hinton, R. L. Usinger Collectors / Ambrysus pygmaeus La Rivers determined by Ira La Rivers 1948 (1³ EMEC); Real de Arriba, Temescaltepec [Temascaltepec], Mex., VI-5-1933 / H. E. Hinton, R. L. Usinger Collectors / Ambrysus pygmaeus La Rivers 1953 (Ira La Rivers) (1♂ CNIN). MORELOS: Cuernavaca, Mex, 1934 / H. E. Hinton (2♀ EMEC); Cuernavaca, VI-1934 Mex / H. E. Hinton Collector (1♀ EMEC). OAXACA: km 72 carr. Putla-Tlaxiaco, 16 km SW of Tlaxiaco, Pte. Los Pinos 17º 11' 11.3'' N, 97º 45' 10.6'' W, 2083 m, 31-May-2012, DRV & PRH colls., L-1401 (1♀ UMC); Mpio. Putla Villa de Guerrero, Putla de Guerrero, Pte. La Cuchara, 17º 01' 06.7'' N, 97º 55' 11.8'' W, 711 m, 30-May-2012, DRV & PRH colls., L-1396 (2♂, 2♀ UMC); Mpio. Putla Villa de Guerrero, Pluta de Guerrero, 17º 02' 21.5'' N, 97º 54' 42.9'' W, 767 m, 30-May-2012, DRV & PRH colls., L-1397 (2³ UMC); Mpio. Tlaxiaco, km 81 carr. Putla-Tlaxiaco, San Juan del Río [Río de Ocotepec], Río Ocotepec, 17º 10' 27'' N, 97º 46' 17.8'' W, 1967 m, 31-May-2012, DRV & PRH colls., L-1400 (1♂ UMC).
description: Published as part of Reynoso-Velasco, Daniel, Sites, Robert W. & Novelo-Gutiérrez, Rodolfo, 2016, The Ambrysus Stål (Heteroptera: Naucoridae: Cryphocricinae) of Mexico: Revision of the subgenus Syncollus La Rivers in Zootaxa 4126 (1), DOI: 10.11646/zootaxa.4126.1.2, http://zenodo.org/record/257651