Canadian Journal of Arthropod Identification

Taxonomic revision of the Nearctic erosa species group of Phymata Latreille, 1802 (Heteroptera: Reduviidae: Phymatinae)

CJAI 41 -- October 1, 2020

Paul Masonick & Christiane Weirauch

| Abstract | Introduction | Checklist | Materials & Methods | Species Key | Taxonomy | Acknowledgments | References | PDF | Cite |
| Appendix |

Phymata arctostaphylae Van Duzee, 1914
    Figs 4A–E, 20B, 21R. Map 2.

Phymata erosa arctostaphylae Van Duzee, 1914
Van Duzee, 1914: p11 (original description)
Phymata arctostaphylae Van Duzee, 1914
Evans, 1931: p719 (revision); Kormilev, 1962: p404 (revision); Henry and Froeschner, 1988: p602 (catalog); Froeschner and Kormilev, 1989: p45 (catalog)

Diagnosis: Recognized from other species of the Nearctic erosa group by the following combination of characters: (1) the relatively large size (~7.5–10 mm), (2) dark red to mahogany body color, and (3) corium without a conspicuous transverse band.

Redescription: Male: Medium to large, total length: ~7.70–8.61 mm, width across lateral angles of pronotum: ~3.06–3.65 mm. STRUCTURE: HEAD (Fig. 4A): distiflagellomere subequal to or longer than pedicel + basiflagellomere (dflg : pd + bflg = ~1.04). THORAX (Figs 4A,D, 20B): thoracic surface matte; anterior pronotal disk without elongated setaceous granulation; posterior pronotal disk rugose; area between lateral pronotal notch and longitudinal carina of the posterior pronotal lobe usually devoid of granulation; longitudinal carina without prominent tubercle; lateral margin of anterior pronotal lobe not keeled; lateral notch of medium depth; lateral margin of pronotum from lateral notch to lateral angle smooth or with light crenulation; lateral angle prominent and acute; posterior angle prominent and acute; lateral surface of forefemur smooth or sparsely granulated; lateral surface of thorax smooth or sparsely granulated; forewing membrane hyaline. ABDOMEN (Fig. 4B): posterior corners of connexiva of abdominal segments 2–4 weakly serrate or dentiform; lateral margins of connexiva of abdominal segments 4–5 sinuous; lateral margins of connexiva of abdominal segments 3–6 with or without fine granulation; connexivum of abdominal segment 5 twice as wide as connexivum of abdominal segment 4; connexivum of abdominal segment 6 trapezoidal, anterior margin roughly twice as wide as posterior margin. COLORATION (Figs 4A): body predominantly dark red to mahogany in color, head and thorax sometimes very dark, usually with lightly colored fine granulation; anterior pronotal lobe never with contrasting marking; forefemur dark red; corium without a conspicuous transverse band. Female: Large, total length: ~8.96–10.14 mm, width across lateral angles of pronotum: ~3.43–4.09 mm. STRUCTURE: HEAD (Fig. 4A): distiflagellomere shorter than length to pedicel + basiflagellomere (dflg : pd + bflg = ~0.78). COLORATION (Fig. 4A): mostly dark red to mahogany, similar to males but slightly less dark overall.

Biology: Phymata arctostaphylae inhabits chaparral of California and northern Baja California’s coastal mountain ranges and has been collected from Arctostaphylos Adans. spp. manazanitas (Ericaceae) during the months of August through October. Despite its frequently noted association with Arctostaphylos, both males and females have also been collected from various Asteraceae including Haplopappus Cass., Chrysanthemum L., and Gutierrezia Lag. Specimens have been collected at elevations ranging between 22–2,014 m above sea level.

Distribution: Endemic to south/central California and northern Baja California.

Discussion: This striking species is rarely encountered in the wild and represented by relatively few specimens in entomological collections. Based on molecular data, P. arctostaphylae appears to be very closely related to other western members of the americana species complex (i.e., P. metcalfi and P. obscura) (Masonick and Weirauch, 2020).

Identification remarks: Along with male P. pennsylvanica, male P. arctostaphylae are the only members of the erosa group with distiflagellomeres that exceed the combined lengths of the preceding two segments. Other than this and its distinctive coloration, useful characteristics that help distinguish P. arctostaphylae from other Nearctic erosa group taxa include: (1) hyaline forewing membranes, (2) shallow lateral notch (relative to other members of the americana species complex), (3) dorsal surface of pronotum uniform in color with fine, lightly colored granulation, and (4) absence of granulation patch on the pronotum between lateral notch and longitudinal carina.

Type information: The holotype is located at the California Academy of Sciences and is a female specimen beaten from Arctostaphylos near Morena Dam in southern California (Van Duzee 1914). Only images of this specimen were examined.
HOLOTYPE: Female: USA: California: San Diego Co.: 15 Oct 1913, E. P. Van Duzee (CAS). Fig. 21R

Additional material examined: See Appendix; 55 specimens, including 23 adult males and 31 adult females.