Australambrysus plax species complex Checklist Australambrysus acutangulus (Montandon, 1897a) Australambrysus aguaro n.sp. Australambrysus alvarado n.sp. Australambrysus clavieri n.sp. Australambrysus planus (La Rivers, 1951) Australambrysus plax (La Rivers, 1967) Australambrysus siolii (De Carlo, 1966) Australambrysus teutonius (La Rivers, 1951) Diagnosis. All species in this complex are diagnosed by having the propleura tightly appressed to the probasisternum and prosternellum, thereby concealing part of the prosternellum (Fig. 2a). Apparently, this condition independently evolved in the Ambrysus subgenus Syncollus of North America. The genera Ambrysus and Australambrysus are both members of the subfamily Ambrysinae. In other species of Australambrysus, the propleura are not tightly appressed to the probasisternum and prosternellum, although the propleura extend beneath and partially obscure view of the prosternum (Fig. 2b). Discussion. I refer to this group as the A. plax species complex because it is this species upon which I compare the three new species and to which they are sister. Additional putatively undescribed species in this complex from Brazil, Colombia, and Peru might be added as future studies warrant. This neotropical genus is in need of revision and has many undescribed species in various museums; other species are known from only the original descriptions of more than a century ago. Consequently, it would be premature to designate additional species complexes at this time.

Published as part of Sites, Robert W., 2023, The Australambrysus plax (La Rivers, 1967) species complex (Heteroptera: Naucoridae), with descriptions of three new species, pp. 318-332 in Zootaxa 5278 (2) on pages 319-320, DOI: 10.11646/zootaxa.5278.2.5, http://zenodo.org/record/7906228