Ambrysus variegatus Usinger

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 : 435-438

Ambrysus variegatus Usinger

( Figs. 10–12 )

A. variegatus Usinger 1946 : Univ. Kans. Sci. Bull., 31: 200–202 (original description).

Supplemental description. Female. Mediosternite VII (SGP) asymmetrical; left margin with a small and inconspicuous apical lobe; right margin without lobe; central lobe clearly concave medially, giving the appearance of two lobes; posterolateral corners subtriangular, pointed, extending posteriorly further than central lobe ( Fig. 10B ).

Male. Accessory genitalic process of tergum VI curved to right at approximately 35 degrees close to proximal third, angled again at approximately 90 degrees almost at mid-length to continue perpendicular to body axis ( Fig. 10C ). Medial lobes of tergum VIII (pseudoparameres) symmetrical, posterolateral and posteromesal corners broadly rounded, posterior margin almost straight ( Fig. 10D ). Phallosoma elongate, linear, slender, tapering dorsoapically; endosomal sclerites knob-like apically, with conspicuous denticles; right sclerite extending basally further than left sclerite ( Fig. 10E ). 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. 10F ).

Diagnosis. This species can be distinguished from the other three in this section by the female SGP with a rounded and inconspicuous apical lobe on the left margin and symmetrical subtriangular posterolateral corners ( Fig. 10B ). Additionally, the male AGP widens distally to a broadly rounded and laterally directed apex ( Fig. 10C ) and the pseudoparamere posterolateral corners are broadly rounded ( Fig. 10D ).

Comparative notes. This species is superficially similar to A. schuhi . The shapes of the SGP of the two species also are comparable, but with notable differences (see Comparative notes for A. schuhi ). The male AGP of A. variegatus widens apically, whereas it tapers in A. cosmius and A. schuhi .

Discussion. This species measures 11.04–12.80 mm in length and 6.72–7.76 mm in width. Usinger (1946) considered this species to be similar to Ambrysus bergi Montandon (currently in the genus Australambrysus Reynoso & Sites) and A. guttatipennis Stål. In the original description, Usinger mentioned that eight additional specimens from Mexico were similar to his A. variegatus , but smaller and with morphological variation on the head and prothorax when compared with the specimens in the type series (from Costa Rica). Because of that reason, he did not consider the Mexican specimens as representatives of his new species. No further information was provided on the eight Mexican specimens. Based on examination of specimens of Ambrysus in different collections and the extensive collecting through Mexico for this project, we consider this to be a Central American species not likely distributed in Mexico.

This species could be more closely related to A. schuhi than to A. cosmius ; unfortunately, this concept could not be corroborated in the recent molecular analysis ( Reynoso-Velasco & Sites 2021) because the authors were not able to include representatives of A. variegatus .

Variation. No variation was detected in the diagnostic features.

Type locality. Costa Rica: west of Cartago (4,700 ft).

Repository. Male holotype ( Fig. 11 ) is housed at the CAS.

Published records: Costa Rica: Cartago, San José ( Usinger 1946, La Rivers 1971, Herrera 2013).

New records: Costa Rica: Heredia, Puntarenas.

Distribution. This species is currently known to occur only in Costa Rica. The recorded localities, all below an elevation of 2,000 meters, are located in the central and northern part of the country ( Fig. 12 ), in theGuatuso-Talamanca and Puntarenas-Chiriquí biogeographical provinces, with most of the records in the latter province. Two of the specimens examined (1♀ SEMC; 1♀ UMC) were collected syntopically with the holotype of A. harmodius La Rivers at Río Virilla.

Type material examined. HOLOTYPE ♂ (by original designation). COSTA RICA: W of Cartago, C.A., 10-VI-[19]32, 4700 ft, B.S. Kaiser / HOLOTYPE variegatus Usinger / 12 / California Academy of Sciences Type No. 7168. PARATYPES: same data as holotype (1♀ EMEC). [CARTAGO]: nr. Tajar [Tejar del El Guarco], 10-VI-[19]32, B.S. Kaiser / PARATYPE variegatus Usinger / 11 (1♂ EMEC). [SAN JOSÉ]: nr. Santa María [de] Dota, 23-VI-[19]32, 5000 ft, B.S. Kaiser / PARATYPE variegatus Usinger / Ambrysus variegatus Usinger determined by Ira La Rivers '50 (1♀ SEMC); San José, VI & VII-1931, Heinrich Schmidt / bought from Heinrich Schmidt / 325 / PARATYPE variegatus Usinger (1♀ UMC).

Additional material examined. COSTA RICA: Río Virilla, 26-XII-1931, Heinrich Schmidt / purchased from collector / Ambrysus variegatus Usinger determined by Ira La Rivers 1948 (1♀ SEMC; 1♀ UMC). [CARTAGO]: Turrialba , Río Tuis (800 msnm), 08-IV-1993, R. Novelo coll. (1♀ UMC). HEREDIA: Río Sarapiqui (margin) just E of Hwy 4 [126], 10º23.22'N, 84º08.20'W, alt. 620', 25-VI-2003, A.E.Z. Short coll. (1♂ UMC). PUNTARENAS: Qda. Máquina at Crandall Reserve , Instituto de Monteverde , 10º18'29.80''N, 84º48'29.56''W, elev. 1400 m, 17-IV-2021, R.W. Sites coll., rootmats in current (1♂ UMC). [ SAN JOSÉ]: San José, 18-IV- [19]12, C.R. / Mus. Expd. S. Meek coll. / Field Museum Coll. (1♂ FMNH); San José, VI & VII-1931, Heinrich Schmidt / bought from collector (2♂ SEMC); same but / bought from Heinrich Schmidt / Ambrysus variegatus det. R.L. Usinger (1♂ UMC); same but Ambrysus variegatus det. H.E. Hungerford (1♂ UMC) .

Figures

FIGURE 10. Structures of Ambrysus variegatus Usinger. (A) dorsal habitus of female paratype (yellow and white arrows indicate light marks at lateral and posterior margins of corium, respectively), (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). al = apical lobe.

FIGURE 11. Male holotype and labels of Ambrysus variegatus Usinger.

FIGURE 12. Distribution of Ambrysus variegatus Usinger.