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 fasciata (Gray, 1832)
    Figs 6A–E, 20D, 21F. Map 4.

Syrtis fasciatus Gray, 1832
Gray, 1832: p242 (original description)
Phymata wolffi Stål, 1876
Stål, 1876: p133 (original description); Kormilev, 1962: p406 (synonymy)
Phymata fasciata (Gray, 1832)
Melin, 1931: p9 (revision);Kormilev, 1962: p305 (revision); Henry and Froeschner, 1988: p602 (catalog); Froeschner and Kormilev, 1989: p51 (catalog)
Phymata fasciata georgiensis Melin, 1931
Melin, 1931: p9 (original description); Kormilev, 1962: p406 (synonymy)
Phymata fasciata fasciata (Gray, 1832)
Kormilev, 1962: p305 (revision); Henry and Froeschner, 1988: p603 (catalog); Froeschner and Kormilev, 1989: p52 (catalog)

Diagnosis: Recognized from other species of the Nearctic erosa group by the following combination of characters: (1) large size (females > ~8 mm, males > ~7.5 mm), (2) deep lateral notch, (3) integument lacking elongated setaceous granulation, (4) keeled margin of the anterior pronotal lobe, (5) conspicuous cluster of raised granules on the pronotum mesad to lateral notch, and (6) a right or obtuse lateral angle.

Redescription: Male: Medium to large, total length: ~7.61–9.07 mm, width across lateral angles of pronotum: ~2.97–3.40 mm. STRUCTURE: HEAD (Fig. 6A): distiflagellomere of male shorter than pedicel + basiflagellomere. THORAX (Figs 6A,D, 20D): thoracic surface glossy; 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 keeled and semicircular; lateral notch deep; lateral margin of pronotum from lateral notch to lateral angle smooth or with light crenulation; lateral angle right or obtuse; posterior angle prominent, right or acute; lateral surface of forefemur smooth or sparsely granulated; lateral surface of thorax moderately granulated; forewing membrane brown, cloudy, never hyaline. ABDOMEN (Fig. 6B): posterior corners of connexiva of abdominal segments 2–4 strongly 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 6A–D): variable; body usually sepia or cream colored and marked with brown bands; thorax, corium, and connexiva with soft pink or roseate colored markings; anterior pronotal lobe usually with a well-defined light-colored “M”-shaped pattern that is bordered by strong dark markings; forefemur darkened (olive green, brown, or blackish); corium with a conspicuous transverse band. Female: Medium to large, total length: ~8.62–9.60 mm, width across lateral angles of pronotum: ~3.25–3.73 mm. THORAX (Fig. 6E): lateral angle obtuse. COLORATION (Figs 6A,B,E): variable; generally similar to that of males but overall lighter in color and the forefemur pale, never darkened.

Biology: Phymata fasciata has been collected from a broad range of flowering plants spanning at least ten different families and a number of host plants unique for erosa group taxa including Cacalia Kuntze, Conoclinium DC., Helenium L., Leucanthemum Mill., Sedum L., Geranium L., Mentha L., Pycnanthemum Michx., Clematis L., Cephalanthus L., and Verbena L.. Dodson and Marshall (1984) documented postcopulatory mate guarding behavior in P. fasciata and demonstrated evidence that sexual selection may favor males with longer hind legs. Specimens have been collected at elevations ranging between 2–1,963 m above sea level.

Distribution: This widespread species is found throughout the southeastern United States, New England, southern Great Plains and as far west as Arizona and south into Mexico. The northern limit of the range of P. fasciata corresponds roughly to the 40th parallel north. This species is mostly absent from the Great Lakes region and likely does not occur in Canada. Based on our survey of museum specimens, iNaturalist observations, and new state records reported by Swanson et al. (2017) and Swanson (2019), it is clear that the range of this species extends far into the interior of North America and is not confined along the Atlantic and Gulf Coasts.

Discussion: Phymata fasciata is one of the most common species of ambush bugs in eastern North America. The P. fasciata treated by Kormilev (1962) included three subspecies in addition to the nominate. Two of these subspecies, P. fasciata mexicana and P. fasciata mystica are elevated here to species rank based on differences in their morphology and molecular evidence (see Masonick and Weirauch, 2020). The remaining subspecies, Phymata fasciata panamensis Kormilev, 1962 from Panama, is herein synonymized with P. mexicana. Phymata fasciata overlaps with many species across its broad range but can be distinguished using the morphological characters highlighted above.

Identification remarks: In addition to the characters highlighted in the diagnosis, P. fasciata can be recognized by (1) the semicircular outline of the anterior pronotal lobe, (2) prominent knoblike tubercle on the longitudinal pronotal carina, (3) sinuous lateral margin of connexiva of abdominal segments 4–5, (4) glossy thoracic cuticle, and (5) well-defined “M”-shaped banding pattern on the posterior lobe. This species shares much in common with P. mexicana but has a more subtle lateral angle, a posterior corner of the connexivum of abdominal segment 5 that is less sharp/acute, and lighter coloration. Males often have darkened heads, thoracic segments, and forelegs, but these areas are never quite as dark as that of P. mexicana.

Type information: Kormilev (1962) designated the type of Phymata fasciata georgiensis Melin as the neotype for Phymata fasciata (Gray) and deposited it in the Swedish Museum of Natural History, Stockholm, Sweden. Only images of this type were examined.
NEOTYPE: Male: USA: Georgia, Morrison (NRM). Fig. 21F. Image:

Additional material examined: See Appendix; 285 specimens, including 158 adult males and 124 adult females.