Ambrysus tricuspis La Rivers

Sites, Robert W. & Reynoso-Velasco, Daniel, 2015, Review of the Ambrysus stali La Rivers species complex (Heteroptera: Nepomorpha: Naucoridae) with the description of a new species from Mesoamerica, Zootaxa 4018 (2), pp. 279-291 : 290

Ambrysus tricuspis La Rivers

( Figs. 1 , 7 )

Ambrysus tricuspis La Rivers 1974 : Biol. Soc. Nevada Occas. Pap. 2–3.

Discussion. This species is known only from the holotype and allotype, which were collected together in northern Colombia. No information regarding habitat or biology was given in the original description. It differs from A. bifidus by the unbifurcated median lobe of the subgenital plate ( Fig. 7 E). Although La Rivers (1974) suggested the male accessory genitalic process is more massive and elongated laterally ( Fig. 7 B) than in A. bifidus , this feature exhibits intraspecific variation in other species of Ambrysus , including within this species complex. Specifically, Nieser (1975) documented sufficient intraspecific variation in the shape of the accessory genitalic process among paratypes of A. bifidus from Suriname that its precise shape should not be considered a reliable diagnostic attribute. La Rivers made no attempt to distinguish this species specifically from A. scolius , but thought the "three-pointed subgenital plate" and "exaggerated dog's head outline" of the male accessory genitalic process would satisfactorily distinguish A. tricuspis from all congeners. Although we are unable to find reliable characters to distinguish A. tricuspis from A. scolius , the slight difference in shape of the male accessory genitalic process, the geographic distance between the known ranges, and the paucity of specimens are enough that we chose not to synonymize these species at this time. More specimens of both species are needed to determine the extent of intraspecific variation in these features, which will then enable us to more effectively address the validity of this species.

Type locality. COLOMBIA, Bolivar Department. Type specimen is housed at CAS.

Material examined. COLOMBIA: Bolivar, San Marcos / (reverse side of locality label) 1964 Aug 8, O. Pinada / Ambrysus tricuspis Holotype / California Academy of Sciences Type No. 13406 / Ira La Rivers Collection Bequeathed to the California Academy of Sciences (♀, CAS); same data, Allotype (♂, CAS).

Figures

FIGURE 1. Distribution of species in the Ambrysus stali species complex.

FIGURE 7. Structures of Ambrysus tricuspis (A) dorsal habitus of holotype, (B) 6 th and 7 th abdominal terga of male, (C) ventral and left sides of phallosoma, (D) 8 th abdominal tergum showing medial pseudoparameres, (E) terminal abdominal sterna of holotype showing subgenital plate with posterior and lateral margins outlined in black (terminal terga missing).