Apiomerus immundus Bergroth, 1898

Masonick, Paul & Weirauch, Christiane, 2022, Taxonomic revision of the Apiomerus maya species group (Heteroptera: Reduviidae: Harpactorinae), Zootaxa 5154 (5), pp. 537-556 : 541

Apiomerus immundus Bergroth, 1898

Figs 1A , 2A, 2G , 3A, 3E

Apiomerus immundus Bergroth, 1898: 307 . Syntype (s): Mexico; MZH.

Apiomerus immundus: Champion (1899: 238) (revision), Van Duzee (1916: 30) (catalog),

Wygodzinsky (1949: 17) (catalog), Costa Lima et al. (1951: 340) (revision), Maldonado (1990: 5) (catalog).

Revised diagnosis: Recognized by the combination of the following characteristics: (1) relatively small size (<14 mm in length) and predominantly brown body and hemelytra, (2) males with lyre-shaped medial process of the pygophore with broadly spaced, short rami, (3) basal dorsolateral sclerites of the endosoma of moderate length, oblong, and with fine sculpturing, and (4)>26 endosomal denticles.

Redescription (based on the lectotype only): Male: Small, 11.45 mm in length, width across humeral angles 3.47 mm. COLORATION: Mostly brown; anterior pronotal lobe dark brown, posterior lobe brown ( Fig. 1A ); corium brown, veins near forewing membrane largely lacking light coloration, quadrate cell of the corium is not outlined in white or pale-yellow; entire forewing membrane brown with dark spots; basal spot of connexivum 7 roughly twice the size of marking on the preceding segment (from dorsal view); lateral spots of abdominal sterna absent. STRUCTURE: Medial process of pygophore lyre-shaped in caudal view, rami short and nearly straight ( Fig. 2A ); paramere weakly bent, with bristles subequal to or slightly longer than its maximal width ( Fig. 2G ); dorsal phallothecal sclerite lacking distinct arrow-shaped in dorsal view, without pair of strongly developed triangular projections near base, apex of dorsal phallothecal sclerite truncate and reflexed ( Fig. 3A ); basal dorsolateral sclerites of endosoma of moderate length, oblong, and covered with fine granules basally; dorsal surface of endosoma with>26 denticles arranged longitudinally; dorsolateral surface of endosoma with distinct sclerotization near base.

Female: Unknown.

Biology: Unknown.

Distribution: The geographical range of this species remains unknown. The type specimen was collected in Mexico, but no additional locality data was provided.

Discussion: This species is included in this revision based on its general appearance and the many male genitalic similarities it shares with species of the maya group, such as the lyre-shaped medial process of pygophore, enlarged basal dorsolateral sclerites of the endosoma, and high number of endosomal denticles. This species however lacks the distinct arrow-shaped dorsal phallothecal sclerite that other maya group species possess ( Fig. 3A ) and has heavier lateral sclerotization along the dorsolateral surface of endosoma basally ( Figs 3A, 3E ). Szerlip (1980) included A. immundus among his A. subpiceus species group, a likely artificial grouping that he referred to as “a catchall for species from Central Mexico, the Yucatan Peninsula and Cuba ” but did not examine Bergroth’s type specimen. Overall, A. immundus appears most similar to A. maya but lacks the paired triangular projections at the base of the dorsal phallothecal sclerite, has slightly longer, more oblong dorsolateral sclerites of the endosoma with finer sculpturing, and appears to possess more endosomal denticles (>26).

Type information: The species was described based on an unspecified number of male individuals ( Bergroth 1898). A single type of Bergroth from MZH, subsequently provided with a curatorial syntype label, has been examined ( Fig. 1B ). As the original description does not exclude the possibility that the species was described based on more than one individual, following Recommendation 73F of ICZN (1999), the examined specimen is regarded as a syntype, and here designated as lectotype of A. immundus .

Type material examined: Lectotype (present designation): ♂, MEXICO: exact locality and date unknown ( UCR _ ENT 00040816 ) ( MZH) ( Fig. 1A ).

Figures

FIGURE 1. Dorsal habitus images of (A) A. immundus Bergroth, 1898 [♂ LECTOTYPE = UCR_ENT 00040816], (B) Apiomerus maya Dispons, 1971 [♀ = UCR_ENT 00013169, ♂ HOLOTYPE = UCR_ENT 00038047], (C) A. pipil Dispons, 1971 [♀ = AMNH_PBI 00218895, ♂ = UCR_ENT 00032865], and (D) A. venosus Stål, 1872 [♀ = UCR_ENT 00031790, ♂ = UCR_ENT 00032336]. All scale bars represent 4 mm.

FIGURE 2. (A–F) Caudal views of the pygophores (pyg) of males of the maya species group displaying the bifid medial process with rami (rm). In these taxa, the base of the medial process is greatly reduced giving the impression of the rami being inserted directly on the posterior rim of the pygophore. The rami are often broadly spaced from one another and render the medial process either V-shaped, as frequently observed in A. pipil (see C), or lyre-shaped (most male A. venosus). Figs. A– F are not to scale. (G–J) Dissected right parameres. All scale bars for Figs. G– J represent 0.25 mm.

FIGURE 3. Dorsal (A–D) and lateral (E–H) views of the aedeagus of males of the maya species group.An arrow-shaped dorsal phallothecal sclerite (dps) is commonly seen in males of these species (subconical in A. immundus). Note the paired triangular projections (tp) positioned basally on the dps of Apiomerus maya (B & F); these projections are absent in other maya group taxa. The basal dorsolateral sclerites of the endosoma (bdls) can be short and round (A. maya), moderately elongated with fine sculpturing basally (A. immundus), or greatly elongated and slightly twisted (A. pipil and A. venosus). The number of peg-like endosomal denticles (ed) aligned longitudinally along the distal dorsal lobes of the endosoma (ddl) varies across the group. In some taxa, notably A. immundus and some A. venosus, lateral sclerotizations of the endosoma (ls) may be observed along the endosoma’s proximal dorsolateral surface. All scale bars represent 0.5 mm.