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 luteomarginata Kormilev, 1957
    Figs 8A–E, 20F, 21N. Map 6.

Phymata luteo-marginata [sic] Kormilev, 1957
Kormilev, 1957: p130 (original description)
Phymata luteomarginata Kormilev, 1957
Kormilev, 1962: p472 (revision); Henry and Froeschner, 1988: p603 (catalog); Froeschner and Kormilev, 1989: p54 (catalog)

Diagnosis: Recognized from other species of the Nearctic erosa group by the following combination of characters: (1) shallow lateral notch, (2) crenulated lateral pronotal margin, and (3) conspicuous right or acute posterior angle.

Redescription: Male: Small to medium, total length ~6.30–7.45 mm, width across lateral angles of pronotum: ~2.27–2.99 mm. STRUCTURE: HEAD (Fig. 8D): distiflagellomere of male subequal in length to pedicel + basiflagellomere. THORAX (Figs 8A,C,D, 20F): thoracic surface matte; anterior pronotal disk sometimes with very short setaceous granulation; posterior pronotal disk rugose in some populations; area between lateral pronotal notch and longitudinal carina of the posterior pronotal lobe usually with diffuse granulation; longitudinal carina without prominent tubercle; lateral margin of anterior pronotal lobe not keeled and lightly crenulated; lateral notch shallow or of medium depth; lateral margin of pronotum from lateral notch to lateral angle smooth or with light crenulation; lateral angle right or 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 or brown. ABDOMEN (Fig. 8B): posterior corners of connexiva of abdominal segments 2–4 inconspicuous/subtle; lateral margins of connexiva of abdominal segments 4–5 sinuous or convex; 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 8A–D): variable; anterior pronotal lobe with or without dark marking; forefemur pale, never darkened; corium with a conspicuous transverse band; connexiva of abdominal segments 3–4 usually without dark basal spots. Female: Small to medium, total length: ~6.99–8.97 mm, width across lateral angles of pronotum: ~2.63–3.23 mm. COLORATION (Figs 8A,B,E): similar to male but generally lighter-colored overall, body usually pale-yellow with brown markings.

Biology: This species has been collected from Eriogonum fasciculatum Benth. (Polygonaceae), Sphaeralcea A. St.-Hil. (Malvaceae), and Purshia DC. ex Poir. (Rosaceae).

Distribution: Found primarily in the Mojave and Great Basin Deserts of California and Nevada. Populations also inhabit portions of the Sierra Nevada mountain range.

Discussion: Kormilev (1957) described P. luteomarginata from a singleton male specimen and designated no secondary types. He was particularly struck by this specimen’s unusual coloration having a mostly pale-yellow anterior pronotal lobe and testaceous (reddish-brown) remainder of the pronotum. We here expand the concept of P. luteomarginata to include slightly darker forms found elsewhere in the Mojave and southern Great Basin Region. Phymata luteomarginata is morphologically similar to both P. borica and P. paraborica sp. nov. but can be distinguished using molecular data (Masonick and Weirauch, 2020) and the combination of characters given in the diagnosis and identification remarks below.

Identification remarks: The following attributes can help distinguish P. luteomarginata from other western taxa: (1) well-developed and diverging frontal processes (compare with P. borica or P. paraborica), (2) flattened anterior pronotal disk with very small setaceous granulation and a pair of small raised tubercles along its posterior margin (compare with P. metcalfi or P. paraborica sp. nov.), (3) rugose posterior pronotal disk, and (4) distiflagellomere of males subequal to pedicle + basiflagellomere. The lateral notch of P. luteomarginata tends to be deeper than that of P. borica or P. paraborica sp. nov. Many P. luteomarginata specimens have short setaceous granulation covering parts of the head and thorax, however this granulation is never as elongate as in P. rossi or P. saileri. Phymata luteomarginata inhabiting the Sierra Nevada mountains have cloudier forewing membranes and darker coloration overall than those found elsewhere.

Type information: The holotype was examined and is deposited in the National Museum of Natural History in Washington D.C.
HOLOTYPE: Male: USA: Nevada: Dixie N. F., 01 Jul 1937, D. J. & J. N. Knull (UCR_ENT 00008099) (USNM). Fig. 21N.

Additional material examined: See Appendix; 38 specimens, including 25 adult males and 13 adult females.