Apiomerus venosus Stål, 1872

Masonick, Paul & Weirauch, Christiane, 2022, Taxonomic revision of the Apiomerus maya species group (Heteroptera: Reduviidae: Harpactorinae), Zootaxa 5154 (5), pp. 537-556 : 546-548

Apiomerus venosus Stål, 1872

Figs 1D , 2E, 2F, 2J , 3D, 3H , 4 , 5

Apiomerus venosus Stål, 1872: 97 . Syntypes: ♂, ♀, Mexico; NHRS.

Apiomerus tristis Champion, 1899: 232 , 238. Syntypes: ♂, ♀, Mexico: Tepic ; BMNH. Syn. nov.

Apiomerus venosus: Stål (1872: 97) (original description), Lethierry & Severin (1896: 146) (catalog), Champion (1899: 233) (key), Wygodzinsky (1949: 18) (catalog), Costa Lima et al. (1951: 342) (revision), Maldonado (1990: 9) (catalog).

Apiomerus tristis: Wygodzinsky (1949: 18) (catalog), Costa Lima et al. (1951: 343) (revision), Maldonado (1990: 9) (catalog).

Revised diagnosis: Recognized by a combination of the following characteristics: (1) relatively large size (> 14 mm in length), (2) well delineated quadrate cell, (3) basal spot of connexivum 7 that is roughly equal in size to or only slightly larger than marking on the preceding segment (from dorsal view), (4) males with lyre-shaped medial process of pygophore with broadly spaced, slightly curved rami, (5) elongate and relatively broad paddle-shaped basal dorsolateral sclerites of the endosoma, and (6) large number of endosomal denticles (about 40), the basal most of which are clustered rather than arranged into two orderly rows.

Redescription: Male: Medium to large, 14.37–16.30 mm in length, width across humeral angles 4.49–4.94 mm (n=5). COLORATION: Mostly black; anterior pronotal lobe dark brown or black, posterior pronotal lobe and legs dark brown or black ( Fig. 1D ); corium black or dark brown, majority of veins white or pale-yellow, usually with all or a majority (3 sides) of the quadrate cell and basal portions of most veins completely outlined; forewing membrane bicolored with basal portion pigmented and distal portion hyaline; basal spot of connexivum 7 roughly the same size as or only slightly larger than marking on the preceding segment (from dorsal view); lateral spots of abdominal sterna 3–5 white or pale-yellow. STRUCTURE: Medial process of pygophore lyre-shaped in caudal view ( Fig. 2E–F ); rami widely separated and slightly bent away (laterally) from one another midway along their length; paramere weakly bent, with bristles subequal to or slightly longer than its maximal width ( Fig. 2J ); dorsal phallothecal sclerite arrow-shaped in dorsal view, without pair of triangular projections near base, apex of dorsal phallothecal sclerite slightly reflexed and shallowly notched; basal dorsolateral sclerites of endosoma elongated, broad at base, tapering distally and slightly rounded and hooked at apex, slightly rotated along length; dorsal surface of endosoma with about 40 denticles total that are clustered proximally and arranged into two longitudinal rows apically; dorsolateral surface of endosoma with slight to moderate sclerotization near base.

Female: Large, 17.50–18.47 mm in length, width across humeral angles 5.29–5.62 mm (n=5).

Biology: Specimens have been collected at elevations ranging from 100–2,000 meters and adults are typically active during June, July, and August.

Distribution: Common throughout central and southern Mexico and has been collected from Guatemala too.

Discussion: Apiomerus venosus displays polychromatism across its range with many central and western populations being very darkly colored (e.g., pronotum, corium, and legs black) and some eastern populations being much lighter in color overall (e.g., pronotum, corium, and legs light brown, see Fig. 4 ). This aptly named species has conspicuous white veins over most of the corium. In some western (Jalisco and Nayarit) and eastern (Chiapas) populations however, the extent of white coloring is limited to portions of the quadrate cell and apical margins of the corium. Stål described A. venosus based on male and female syntypes from Mexico which are housed at the NHRS. We here designate a male specimen (NHRS-GULI 000003183 = UCR_ENT 00041023) as the lectotype ( Fig. 5A– C ). Szerlip (1980) selected Champion’s male syntype of A. tristis (UCR_ENT 00048736) to serve as the lectotype but never published this act it in a Code-compliant way. We were able to examine an image ( Fig. 5D ) of this specimen which is housed at the BMNH and here formally designate it as the lectotype of A. tristis . The main differences between this species and A. venosus are wing color (a highly plastic trait, see Fig. 4 ) and (as noted in Szerlip’s description of the dissected genitalia) the number of endosomal denticles, 19 pairs of the former vs. 22–24 pairs of the latter (another trait that exhibits some plasticity and admittingly difficult to quantify for some specimens). Based on Szerlip’s description of this specimen and careful examination of other A. maya species group specimens collected near the type locality in Nayarit, Mexico which we held to be this species, A. tristis appears to be nothing more than a darker geographical variant of A. venosus . Therefore, we here synonymize the former with the latter.

Type material examined:

Apiomerus venosus Stål, 1872 . Lectotype (present designation): ♂, MEXICO: exact locality and date unknown, Sallé (NHRS-GULI 000003183, UCR _ ENT 00041023 ) ( NHRS). We examined photographs of Stål’s syntype series of A. venosus (4 ♂♂, 6 ♀♀) housed at the NHRS. Images of the these are available at http://www3.nrm. se/en/het_nrm/v/apiomerus_venosus.html and the Heteroptera Species Pages (http://research.amnh.org/pbi/heteropteraspeciespage) .

Apiomerus tristis Champion, 1899 . Lectotype (present designation): ♂, MEXICO: Nayarit: Tepic, July (year unknown), Schumann ( UCR _ ENT 00048736 ) ( BMNH).

Additional specimens examined: 303 ♂♂, 357 ♀♀ (see Appendix).

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.

FIGURE 4. Examples of intraspecific polychromatism across ranges of maya species group taxa.

FIGURE 5. Apiomerus venosus lectotype dorsal habitus (A), specimen labels (B), and caudal view of pygophore (C). The “Allotypus” label associated with this specimen is a curatorial artifact. Dorsal habitus (D) and labels (E) of the A. tristis lectotype (UCR_ENT 00048736). Figures A and D are not to scale. A–C photographed by Gunvi Lindberg (© 2022 NHRS). Original photos cropped, light levels and contrast adjusted. Made available by the Swedish Museum of Natural History under Creative Commons Attribution 4.0 International Public License, CC-BY 4.0.