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A new species of Stilbopogon from the Monvero dunes of California (Tiphiidae, Hymenoptera)
expand article infoLynn S. Kimsey
‡ University of California, Davis, United States of America
Open Access

Abstract

One new species in the brachycistidine tiphiid genus Stilbopogon, monveroensis is described from the Monvero Dunes in Fresno Co., California. A revised key to the species of Stilbopogon is included.

Keywords

Brachycistidinae, costaricaensis, Quemaya

Introduction

Brachycistidine wasps are an obscure group of generally nocturnal aculeate parasitoids. Males are winged and very different appearing than females, in much the same pattern as in the Mutillidae. However, brachycistidines lack any kind of colorful pigmentation, ranging in color from yellowish brown to nearly black. For decades there was a separate taxonomy for males versus females and no sex associations were made until Kimsey (2006). One consequence of making the sex associations was that the genus Quemaya Pate, 1947 (based on males) was predated by Stilbopogon Mickel & Krombein, 1942 (based on females). Stilbopogon, under the old name of Quemaya, was first revised by Kimsey and Wasbauer (1996).

Very little is known about the biology of the Brachycistidinae. The winged males are generally collected in blacklight traps and the wingless females in pitfall traps. Members of this group were assumed to be parasitoids much like the rest of the family. The first host record for any species of Brachycistidinae was found to be a tenebrionid larvae found being attacked by a female Stilbopogon in the daytime (Borowiec and Kimsey 2015).

Males in the genus Stilbopogon exhibit a number of unusual features, even among the brachycistidines. Stilbopogon is the smallest bodied group in the subfamily. The largest males belong to Stilbopogon confusa Kimsey & Wasbauer, which reach 6 mm in length. Males in the majority of species range in length from 3–4 mm. Females are much smaller. There are also a few species of Stilbopogon, including costaricaensis Kimsey & Bohart, and the new species described below, that have proportionally small eyes and even smaller ocelli. These species are also dark brown to black in coloration. These head and coloration modifications suggest that the new species and costaricaensis may actually be diurnal.

Materials and methods

The new species described below was collected in Malaise traps run on the Monvero Dunes in Fresno County, California, in June and July, 2015. This is odd sand dune system is located on top of a ridge in the interior central coastal range of California, between 600 and 670 m above sea level (Fig. 1). It is considered to be the remains of an Upper Cretaceous reef (Stewart 1946). The dunes are vegetated by a combination of inner coastal range and Mojave Desert plant species, including large Ephedra californica plants.

Figure 1. 

Landscape view of Monvero Dunes looking south. Photo courtesy of Michael Powers, U.S. Bureau of Land Management.

Results

Identification key to Stilbopogon males

(modified from Kimsey and Wasbauer 1998)

1 Forewing with two submarginal cells 2
Forewing with one submarginal cell (as in Fig. 2) 5
2 Mandible with two apical teeth; distance between midocellus and closest eye margin less than 1.5 midocellus diameters arenicola (Wasbauer)
Mandible with three apical teeth, one may be very small; distance between midocellus and closest eye margin more than 1.5 midocellus diameters 3
3 Mesopleuron densely punctate, with punctures evenly dispersed over entire surface and 1–2 puncture diameters apart; propodeum coarsely sculptured with irregular demarcation between dorsal and posterior surfaces indicated by rugae confusa (Kimsey & Wasbauer)
Mesopleuron sparsely punctate, with punctures generally 4–6 puncture diameters apart, denser dorsally than posteroventrally, surface above midcoxa nearly impunctate; propodeum smooth, without distinct punctation or rugosities, and no demarcation between dorsal and posterior surfaces 4
4 Midocellus separated from eye margin in front view by more than 2 midocellus diameter; epipygium apically bidentate perpunctata (Cockerell)
Midocellus separated from eye margin in front view by less than 2 midocellus diameters; epipygium apically flat and broadly triangular megalops (Kimsey & Wasbauer)
5 Gular carina with basal tooth-like projection near mandible; clypeus transversely indented, without medial projection, arcuately raised apicomedially; epipygium apex truncate inermis (Malloch)
Gular carina simple; clypeus and epipygium various 6
6 Flagellomeres I and II subequal in length, about twice as long as broad or longer; epipygium apex strongly convex and lip-like marcida (Bradley)
Flagellomeres I shorter than II, and between I.2 and 1.8× as long as broad; epipygium apex medially emarginate or truncate 7
7 Midocellus larger, separated by 2 midocellus diameters or less from nearest eye margin; flagellomere I 1.6× as long as broad or longer 8
Midocellus small, separated by 3 or more midocellus diameters from nearest eye margin; flagellomere I 1.5× as long as broad or shorter 9
8 Midocellus separated from nearest eye margin by 1.5 midocellus diameters or less; epipygial apex convex; clypeus with broad, blunt medial projection, bulging and strongly subtriangular in profile; forewing R1 vein strongly angulate near costal margin, marginal cell broadly parallel-sided mexicana (Kimsey & Wasbauer)
Midocellus separated from nearest eye margin by 1.8–2.0 midocellus diameters; epipygial apex bidentate; clypeus with narrow nose-like or almost digitate medial projection; forewing R1 vein narrowly separated from stigma, curved or indistinguishable near costal margin paupercula (Bradley)
9 Midocellus five or more midocellus diameters from nearest eye margin (as in Fig. 3) 10
Midocellus 3.0–3.5 midocellus diameters from nearest eye margin 11
10 Flagellomere I 1.1–1.2× as long as broad; flagellomere II 1.4× as long as broad; propodeum coarsely sculptured, with irregular, partial transverse carina costaricaensis (Kimsey & Wasbauer)
Flagellomere I 1.4–1.5× as long as broad; flagellomere II 1.8–1.9× as long as broad (Fig. 3); propodeum smooth without sculpturing or transverse carina (Fig. 6) monveroensis Kimsey, sp. nov.
11 Clypeus with small, sharp medial projection, apical truncation 1.5 midocellus diameters wide; epipygial apex medially emarginate, with sublateral carina eurekaensis (Kimsey & Wasbauer)
Clypeus with broad, transverse medial projection subtended by discrete declivity, apical truncation 2 midocellus diameters wide; epipygial apex truncate sonorensis (Kimsey & Wasbauer)

Systematics

Stilbopogon monveroensis Kimsey, sp. nov.

Figs 2–8

Diagnosis

Stilbopogon monveroensis has the small ocelli (Fig. 3), single submarginal cell (Fig. 2), and short broad flagellomeres (Fig. 3) that characterize S. costaricaensis, and less so S. sonorensis and S. eurekaensis. The nasiform clypeus (Figs 3, 4), small eyes, and finely sculptured propodeum (Fig. 6) are diagnostic for this species.

Description

Male. Body (Figs 6, 8); length 2.5–4.4 mm. Head: face (Fig. 3): clypeus with subrectangular medial projection, projection apex 1.0–1.1 midocellus diameter wide, appearing acute in profile (Fig. 5), apicomedial truncation 2.6–2.7 midocellus diameters wide in front view (Fig. 3); mandible with three apical teeth, preapical teeth subequal in length; gular carina simple; flagellomere I length 1.4–1.5× breadth; flagellomere II 1.9–2.0× as long as broad; interantennal distance 1.5 midocellus diameters wide; distance from midocellus to closest eye margin 5.8–6.0 midocellus diameters. Mesosoma: mesopleuron with punctures 2–4 puncture diameters apart; forewing with one submarginal cell; marginal cell small, more than 3× as long as broad, widely separated from costal margin (Fig. 2); propodeum largely impunctate and smooth, with small medial patch of fine rugae. Metasoma: epipygium apicomedially truncate, with two sublateral carinae, each terminating in small tooth, apical surface forming an ovoid, slightly sunken medial area (Fig. 5); paramere gently tapering, apicoventral angle obtuse (Fig. 7). Color: body dark brown to black; antenna pale brown, slightly yellower than legs; wing veins pale brown to transparent, stigma brown; wing membrane untinted.

Figures 2–8. 

Stilbopogon monveroensis male 2 fore and hindwing venation 3 front view of face 4 lateral view of head 5 dorsal view of epipygium 6 dorsal view of body 7 lateral view of male genital capsule 8 lateral view of body. Abbreviations: ae = aedeagus, p = parameres.

Female. Unknown.

Etymology

This species is named after the site of collection in the Monvero Dunes.

Material examined

Holotype male; USA: California, Fresno Co., Monvero Dunes, Monocline ridge, 29 km sw Mendota,10 June 2015, 36.4974, -120.5312, 500 m, MT4 near Ephedra californica, M. Powers. Paratypes: 19 males: 6: same data as holotype; 6: MT1, 36°32'N, 120°33'W, 569 m, 10 June 2015, near Ephedra, M. Powers; 4: MT1, 36°32'N, 120°33'W, 7 July–8 August 2015, M. Powers; 1: 36.539, -120.567, 15–30 June 2015, MT1 near Ephedra californica, M. Powers; 3: 498 m, 17 July 2015, 498 m, 36°32'N, 120°33'W, MT2, Bohart Museum crew. All types are deposited in the Bohart Museum of Entomology, University of California, Davis.

Distribution

This species has only been found in the Monvero Dunes in Fresno Co., California.

Remarks

Most species of Stilbopogon appear to be quite widespread in arid and desert regions of North and Central America. Stilbopogon monveroensis appears to be the exception to this. However, its restricted distribution may be more the result of limited collecting than actual endemism.

Acknowledgements

This study was made possible by logistical and personnel support from the U.S. Bureau of Land Management, particularly with the assistance of Mike Powers.

References

  • Kimsey LS, Wasbauer MS (1996) Revision of the American tiphiid genus Quemaya Pate. Journal of Hymenoptera Research 7(1): 38–47.
  • Kimsey LS, Wasbauer MS (2006) Phylogeny and checklist of the nocturnal tiphiids of the Western Hemisphere. Journal of Hymenoptera Research 15(1): 9–25.
  • Stewart R (1946) Geology of Reef Ridge Coalinga District California. USDI Geological Survey Professional Paper 205-C, 52 pp. https://doi.org/10.3133/pp205C