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 stanfordi Evans, 1931 stat. nov.
    Figs 19A–E, 20Q. Map 17.

Phymata pacifica stanfordi Evans, 1931
Evans, 1931: p726 (original description); Kormilev, 1962: p424 (revision); Henry and Froeschner, 1988: p603 (catalog); Froeschner and Kormilev 1989: p56 (catalog)

Diagnosis: Recognized from other species of the Nearctic erosa group by the following combination of characters: (1) lateral notch of medium depth, (2) integument lacking elongated setaceous granulation but with extensive fine granulation across much of the body, (3) diffuse granulation between lateral pronotal notch and longitudinal carina of the posterior pronotal lobe, (4) punctate posterior pronotal disk, (5) lateral and posterior angles prominent and acute, and (6) forewing membrane usually hyaline.

Redescription: Male: Small to medium, total length: ~7.03–8.13 mm, width across lateral angles of pronotum: ~2.61–2.92 mm. STRUCTURE: HEAD (Fig. 19A,D): distiflagellomere of male shorter than pedicel + basiflagellomere. THORAX (Figs 19A,D, 20Q): 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 diffuse 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 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 finely granulated; forewing membrane hyaline or slightly cloudy. ABDOMEN (Fig. 19B): 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 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 19A,B,D): body overall usually peach-colored or sepia tone with brown markings; anterior pronotal lobe usually with brown marking; forefemur pale, never darkened, sometimes pinkish; corium with a conspicuous tan or peach-colored transverse band. Female: Small to medium, total length: ~7.74–8.84 mm, width across lateral angles of pronotum: ~2.77–3.19 mm. COLORATION (Figs 19A,B,C,E): similar to that of males, but with less strongly contrasting markings; body predominantly peach-colored.

Biology: Specimens have been found on species of Asteraceae.

Distribution: Phymata stanfordi is found in the coastal mountain ranges of central and northern California as well as in the Sacramento Valley.

Discussion: We elevate P. stanfordi to species rank based on its unique morphology (color included) and clear molecular divergence from P. pacifica (see Masonick and Weirauch, 2020). These two taxa are sympatric and found on similar host plants. While sequence data and geometric morphometrics of pronotal shape have thus far failed to clearly separate P. stanfordi and P. metcalfi (Masonick and Weirauch, 2020), we consider both to be good species based on morphological traits (particularly granulation and color) and their geographic distributions.

Identification remarks: Phymata stanfordi is overall very similar to P. metcalfi, but can be separated using a combination of these characteristics: (1) P. stanfordi with distinctive peach or beige body coloration and with extensive fine granulation, (2) area between lateral pronotal notch and longitudinal carina of the posterior pronotal lobe usually with diffuse granulation (never with a dense cluster like P. pacifica, but with more granulation than P. metcalfi), (3) carina of the lateral angle lined with granulation (compare with P. metcalfi where granulation is usually absent), and (4) basal spot on connexiva of abdominal segments 3 and 4 usually absent. The geographic distribution of P. stanfordi is also much smaller than that of P. metcalfi.

Type information: Only paratypes of P. pacifica stanfordi were examined. Evans deposited the holotype in the collection at Stanford University, however we were unable to locate it there or in two neighboring institutions (the California Academy of Sciences and the Essig Museum of Entomology at the University of California, Berkeley).
PARATYPES: USA: California: Santa Clara Co.: Stanford University, 37.42722°N, 122.16917°W, 04 Aug 1928, Carl D. Duncan, 1♂ (UCR_ENT 00096030), 1♀ (UCR_ENT 00096053) (LACM); Jun 1920, Unknown, 1♀ (UCR_ENT 00096054) (LACM); Sep 1897, Johnson, 1♀ (UCR_ENT 00096055) (LACM); Sep 1929, T. Zschokke, 3♀ (UCR_ENT 00096056-UCR_ENT 00096058) (LACM).

Additional material examined: See Appendix; 101 specimens examined, including 63 adult males and 37 adult females.