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 pacifica Evans, 1931
    Figs 13A–E, 20K, 21O. Map 11.

Phymata pacifica Evans, 1931
Evans, 1931: p725 (original description); Kormilev, 1962: p422 (revision); Henry and Froeschner, 1988: p603 (catalog); Froeschner and Kormilev, 1989: p56 (catalog)
Phymata pacifica pacifica Evans, 1931
Kormilev, 1962: p422 (revision); Henry and Froeschner, 1988: p603 (catalog); Froeschner and Kormilev, 1989: p56 (catalog)
Phymata pacifica hainesi Kormilev, 1962 syn. nov.
Kormilev, 1962: p424 (original description); Froeschner and Kormilev, 1989: p56 (catalog)

Diagnosis: Recognized from other species of the Nearctic erosa group by the following combination of characters: (1) deep lateral notch, (2) integument lacking elongated setaceous granulation, (3) prominent granulation patch on the pronotum mesad to the lateral notch, (4) relatively small size (~6.5–8.5 mm), and (5) posterior lateral corners of connexiva of abdominal segments 2–5 weakly dentiform.

Redescription: Male: Small to medium, total length ~6.40–6.76 mm, width across lateral angles of pronotum: ~2.57–2.75 mm. STRUCTURE: HEAD (Fig. 13A,D): distiflagellomere of male shorter than pedicel + basiflagellomere. THORAX (Figs 13A,D, 20K): thoracic surface matte; anterior pronotal disk without elongated setaceous granulation; posterior pronotal disk punctate; area between lateral pronotal notch and longitudinal carina of the posterior pronotal lobe with a distinct granulation patch; longitudinal carina with prominent knoblike tubercle; lateral margin of anterior pronotal lobe not keeled and semicircular; lateral notch deep; lateral margin of pronotum from lateral notch to lateral angle smooth or with light crenulation; lateral angle prominent and acute; posterior angle small and obtuse; lateral surface of forefemur smooth or sparsely granulated; lateral surface of thorax granulated; forewing membrane hyaline. ABDOMEN (Fig. 13B): posterior corners of connexiva of abdominal segments 2–4 inconspicuous/subtle; 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 less than twice as wide as connexivum of abdominal segment 4; connexivum of abdominal segment 6 rhomboidal, anterior and posterior margin roughly the same width. COLORATION (Figs 13A,B,D): variable; anterior pronotal lobe sometimes with a reddish-brown marking; forefemur pale, never darkened; corium with a conspicuous transverse band that is often pinkish or lavender in color. Lateral surface of head and thorax, legs, connexiva of abdominal segments 2–4 and 6–7, and ventral surface of body may be ivory, pale green, or yellowish; the darker markings on the dorsum of the head, pronotum, corium, and connexivum of abdominal segment 5 (and sometimes the anterolateral corner of connexivum of abdominal segment 4) are usually reddish-brown to black. Female: Small to medium, total length: ~7.18–8.77 mm, width across lateral angles of pronotum: ~2.96–3.40 mm. COLORATION (Figs 13A,B,C,E): Body predominantly ivory to pale-green or yellow in color with pink to reddish-brown markings on the dorsum of the head, pronotum, corium, and connexivum of abdominal segment 5.

Biology: Phymata pacifica is common in coastal sage scrub and chaparral communities of coastal California and the Baja Peninsula. While this species has been found on a variety of plants, it is frequently encountered on blooming Eriogonum fasciculatum Benth. Like many ambush bugs, P. pacifica is a generalist predator that preys on a broad range of flower visiting arthropods. Molecular evidence suggests that P. pacifica frequently engages in intraguild predation by consuming beetles, parasitoid wasps and flies, crab spiders, and other predatory true bugs (Masonick et al. 2019). Adults are relatively common from June through September and may be found living in sympatry with P. metcalfi and P. paraborica sp. nov. Specimens have been collected at elevations ranging between 4–1,997 m above sea level.

Distribution: Restricted to California and the Baja California Peninsula.

Discussion: We here treat the nominate subspecies and P. pacifica hainesi Kormilev as P. pacifica. The third subspecies previously recognized, P. pacifica stanfordi Evans, is elevated to species rank in this revision based on molecular evidence, its divergent morphology, and cooccurrence with P. pacifica. Populations in Baja California often are much darker in color than those that occur in California.

Identification remarks: The following attributes can help distinguish P. pacifica from other western taxa: (1) rounded anterior pronotal lobe (compare with the relatively flatter anterior pronotal lobe of P. luteomarginata and P. paraborica sp. nov.), (2) relatively weak posterior pronotal angle (see prominent posterior pronotal angle of P. metcalfi or P. stanfordi), (3) brown wing membrane (compare with the hyaline wing membranes P. luteomarginata or P. metcalfi), and (4) body overall usually ivory in color with reddish-brown to black markings on head and pronotum and a pink or lavender transverse band on the corium.

Type information: Evans’ holotype of P. pacifica is housed at the University of Kansas Biodiversity Institute but only a selection of his paratypes were examined for this revision. Kormilev’s holotype of P. pacifica hainesi was examined and is deposited at the United States National Museum of Natural History in Washington D.C.
HOLOTYPE: (Phymata pacifica Evans, 1931): Male: USA: California: San Diego CO.: 04 Jul 1929, R. H. Beamer, (KU).
PARATYPES: (Phymata pacifica Evans, 1931): USA: California: Marin Co.: Mount Tamalpais, 37.90389°N, 122.59500°W, no date provided, Unknown, 1♂ (UCR_ENT 00086560) (LACM). Orange Co.: Orange County, no specific locality, 33.74430°N, 117.87407°W, 14 Jul 1929, R. H. Beamer, 1♀ (UCR_ENT 00070067) (KU). San Diego Co.: San Diego County, 32.71528°N, 117.15639°W, 04 Jul 1929, R. H. Beamer, 1♂ (UCR_ENT 00070066) (KU).
HOLOTYPE: (Phymata pacifica hainesi Kormilev, 1962): Male: MEXICO: Baja California: Calamajué (as Calamujuet), May 1889, C. D. Haines, (UCR_ENT 00008102) (USNM). Fig. 21O.

Additional material examined: See Appendix; 932 specimens, including 531 adult males and 386 adult females.