Australambrysus plax (La Rivers, 1967), 2023

Rodrigues, Higor D. D., Canejo, Rafael P. R. & Sites, Robert W., 2024, New species, new combinations, and morphological notes of South American Ambrysinae (Heteroptera: Naucoridae), Zootaxa 5447 (2), pp. 199-224 : 200-201

Australambrysus plax (La Rivers, 1967) species complex

Discussion. The A. plax species complex is diagnosed by having the propleura tightly appressed to the probasisternum and prosternellum, thereby concealing part of the prosternellum—although this condition also occurs in the subgenus Ambrysus (Syncollus) La Rivers, 1965 , from North America ( Sites 2023a). In addition to this feature, the species in this complex also share: propleuron shagreened throughout, except a thin, glabrous band in the lateral margin ( Figs. 1B , 2B , 3B ); ventrally entirely golden brown, with dense pile of fine hairs, and two glabrous median stripes on abdominal sterna IV–V; at least the posterolateral corners of abdominal segments IV–VI spinose; absence of an accessory genitalic process of male abdominal tergum VI ( Figs. 2C , 3D ); and the male phallosoma with ventral endosomal lobes membranous ( Figs. 2G , 3H ). It is important to note that the diagnostic features listed above are not necessarily exclusive to the complex.

Australambrysus acutangulus ( Montandon, 1897b) and A. fraternus ( Montandon, 1897b) are known only from the male holotypes, which have not been dissected; however, we suspect they have the same features as the other species in the complex. We have other probable Brazilian new species from this complex, which are easily differentiated by the male genitalia and the female abdominal sterna; however, to minimize the risk of describing them as possible future synonyms, the genitalia of A. acutangulus and A. fraternus should be described first.

Figures

FIGURE 1. Australambrysus fraternus (Montandon, 1897), male holotype (MNHN), (A) dorsal, (B) ventral and (C) lateral habitus, (D) holotype labels. Figures © Laurent Fauvre / MNHN. Size bars = 1 mm.

FIGURE 2. Australambrysus planus (La Rivers, 1951), male from Ecuador (UMC), (A) dorsal and (B) ventral habitus, (C) 6th and 7th abdominal terga of male, (D) genital capsule of male, (E) genital capsule with proctiger removed, (F) right paramere, (G) ventral surface of phallosoma. Size bars = 1 mm and applies only to Figs. A–B. lvl = left ventral lobe, rvl = right ventral lobe.

FIGURE 3. Australambrysus tuberculatus n. sp., (A) dorsal, (B) ventral and (C) lateral habitus of male holotype (MZUSP), arrows indicate protuberance of abdominal sternum V, (D) 6th and 7th abdominal terga of male, (E) 8th abdominal tergum of male, (F) genital capsule of male, (G) genital capsule with proctiger removed, (H) ventral surface of phallosoma, (I) terminal abdominal sterna of female, arrows indicate small digitate process on posterior margin of laterosternite VI. Size bars = 1 mm and applies only to Figs. A–B. lsVII = laterosternite VII, sgp = subgenital plate.