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 metcalfi Evans, 1931 stat. restit.
    Figs 9A–E, 20G, 21S. Map 7.

Phymata metcalfi Evans, 1931
Evans, 1931: p723 (original description)
Phymata americana metcalfi Evans, 1931
Kormilev, 1962: p414 (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) lateral notch of medium depth, (2) integument lacking elongated setaceous or extensive granulation, (3) absence of granulation patch between lateral pronotal notch and longitudinal carina of the posterior pronotal lobe, (4) punctate posterior pronotal disk, (5) prominent lateral angle, usually right or obtuse, (6) prominent posterior angle, usually acute or right, and (7) forewing membrane usually hyaline.

Redescription: Male: Medium to large, total length: ~7.16–8.49 mm, width across lateral angles of pronotum: ~2.68–3.43 mm. STRUCTURE: HEAD (Fig. 9A,D): distiflagellomere of male shorter than pedicel + basiflagellomere. THORAX (Figs 9A,D, 20G): 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 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 usually hyaline, brown in some populations. ABDOMEN (Fig. 9B): 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 9A,B,D): variable; anterior pronotal lobe usually with dark marking; forefemur pale, never darkened; corium with a conspicuous transverse. Female: Size variable, total length: ~7.47–9.25 mm, width across lateral angles of pronotum: ~2.79–3.44 mm. COLORATION (Figs 9A,B,C,E): variable.

Biology: Phymata metcalfi has been found on a broad range of hosts including Apocynaceae, Asteraceae, Lamiaceae, Malvaceae, Polygonaceae, and Rosaceae.

Distribution: This species is distributed from southern California to British Columbia.

Discussion and identification remarks: Based on morphological and molecular differences between P. metcalfi, P. americana, and P. obscura, we here elevate this taxon back to its original rank of species. Both P. metcalfi and P. stanfordi are relatively smaller than other members of the americana species complex (~7–9 mm in length). Phymata metcalfi varies greatly in size and color across its distribution. Southern individuals (mainly of the Mojave Desert) are often smaller and appear mostly yellow and lack the dark pronotal and connexival markings that are common among northern individuals. The lateral pronotal angle of specimens from the southern Mojave is often more reduced and obtuse (especially in females) than those from northern populations. Phymata metcalfi is morphologically very similar to P. obscura and is best separated using molecular data and geography. Molecular evidence and pronotal geometric morphometrics has failed to separate P. metcalfi and P. stanfordi. Nevertheless, we treat the two as distinct species based on coloration, degree of granulation across the body, and their geographical distribution. While P. metcalfi is distributed across most of California, P. stanfordi is found primarily in the coastal mountain ranges west of the Central Valley.

Type information: The holotype is deposited in the California Academy of Sciences. Only images of this specimen were examined.
HOLOTYPE: Male: USA: Oregon: Lake Co.: Summer Lake, 28 Jul 1930, H. A. Scullen, (CAS). Fig. 21S
PARATYPES: CANADA: British Columbia: Lillooet, 50.68652°N, 121.93347°W, 02 Sep 1918, Unknown, 1♂ (UCR_ENT 00047811), 1♀ (UCR_ENT00047812) (CAS).

Additional material examined: See Appendix; 684 specimens, including 396 adult males and 281 adult females.