Meximalus skinnerensis Burks

Burks, R. A. & Redak, R. A., 2004, New species of Pteromalidae and Torymidae (Hymenoptera: Chalcidoidea) from California, with taxonomic notes, Zootaxa 606, pp. 1-20 : 7-14

Meximalus skinnerensis Burks , n. sp.

Diagnosis (female). Temples/dorsal eye length 0.38 (Fig. 5) [0.48 in M. heratyi (Fig. 4)]. Metafemur 4.4x longer than broad [3.25x in M. heratyi ]. Profemur 4.8x longer than broad [3.7x in M. heratyi ].

Description. Holotype female. Body length 2.6 mm (14 in relative units used below). No other female specimens known, therefore variation is not addressed.

Color: Head and mesosoma black with weak metallic luster, with white, slightly thickened, setae; eyes and ocelli pinkish white; mandibles centrally light brown, peripherally dark reddish brown; maxillary and labial palps light brown; entire antenna light brown, the flagellum gradually becoming darker apically; tegula and humeral plate light brown, tegula semitranslucent; venation centrally white and peripherally light brown, stigma entirely light brown; all coxae same color as mesopleuron, most of legs light brown, except pro­ and mesofemora and tarsal claws darker brown; gaster brown with varying metallic luster.

Sculpture: Most of head and mesosoma deeply and broadly alveolate, except: clypeus very shallowly alveolate with even shallower indications of radiating striae that are limited to clypeal area; postocciput coriaceous with elongate meshes, sharp transition, very weakly carinate, between occiput and postocciput; frenum not differently sculptured from remainder of scutellum; upper mesepimeron entirely finely alveolate; one large and broad depression along dorsal edge of lower mesepimeron (this divided into pits in most other Pteromalinae ); acropleuron mostly coriaceous but changing to finely alveolate near tegula; visible surface of lateral panels of preaxilla and axilla shallowly alveolate and relatively glossy; prepectus finely and shallowly alveolate; dorsellum smooth; propodeum entirely transverse­alveolate, with callus much more shallowly sculpted and all sunken areas more finely sculpted.

Head (Figs. 5, 8) width 4.8, height 3.5, length 2.2; Dorsal IOD 3.4, ventral IOD 3.6; bottom of toruli about 0.2 above lower eye margin; ITD 0.3; VTD 2.1; MTD 1.15; ocular setae shorter than diameter of an adjacent ommatidium; clypeus shallowly emarginate, lateral incisions of clypeus no deeper or more extensive than median incision; EH 1.9; MS 1.2; MW 1.8; POL 0.9; OOL 1.1; EL 1.3; TL 0.5; malar sulcus present and deep; genal concavity vague and weak, about 0.4x malar space but not defined by a carina or change in sculpture, with a distinct narrow notch for reception of mandible base; genal carina distinct. Scape 1.9:0.4; pedicel 0.6:0.3; the two anelli tiny and strongly transverse; 1st funicular segment as long as broad, slightly shorter than pedicel, following funicular segments increasing in width and decreasing in length until 6th funicular segment twice as broad as long; funicular and claval segments with 1 row of longitudinal sensilla that slightly exceed the segment apex; flagellar setae inconspicuous and appressed to the segments; club slightly shorter than preceding three segments, sensory area tiny and at claval apex. Both mandibles with 3 distinctly separated denticles.

Mesosoma (Figs. 8, 10). Pronotal collar medial length 0.7, width 3.4; mesoscutum length:width 2.0:3.9; scutellum 2.4:2.2 (width at axillular apices); dorsellum <0.1x scutellar length; propodeum length 1.2. Pronotal collar smoothly rounded anteriorly, collum steep and short, visible dorsally for a length of 0.2; lateral panel of pronotum with a deep and narrow, almost vertical and straight, scrobe beginning abruptly near ventral edge of lateral pronotal panel and ending to dorsal surface of pronotum such that the collar has a distinct lateral notch when seen from dorsal view; axillar separation 0.4; axillulae small, about 0.25x scutellar height; scutellum from dorsal view heptagonal, bluntly pointed posteriorly and projecting straight posteriorly over propodeum to end at about the level of nuchal base; frenal separation only apparent at lateral extremes, but frenum comprising ventral surface of scutellar projection; dorsal margin of prepectus shorter than tegula. Propodeum at about a 70° angle with top of scutellum, with a trident­shaped complex of complete median carina and anterior plicae that smoothly unite with the costula near propodeal midlength, ISD 2.15; anterior and posterior plical pits not evident; spiracles emarginate; postspiracular furrow deep, moderately narrow, and uninterrupted, ending in a distinct pit at supracoxal flange; supracoxal flange slightly greater in length than short axis of spiracle, ending near nuchal base; nucha convex, without basal cross­carina and with a very vague basal furrow, 0.5 (from end of median carina)x0.8, extending distinctly beyond metacoxal bases but not reaching their midlength. PRF 2.9:0.6; PRT 2.6:0.4; MSF 2.5:0.5; MST 3.0:0.5; MTF 3.1:0.7; MTT 3.6:0.4; mesotibial spur 0.5; basal mesotarsomere 0.9; metatibial spur 0.4; basal metatarsomere 0.9. FW 9:4.4; CC 3.3; MV 2.1; PMV 1.5; SV 1.2, stigma large and teardrop­shaped, broadening apically, shortest distance from uncal apex to MV 0.6, from stigmal apex to MV 1.1; uncus tiny, less than 0.2x greatest stigmal width; venational setae as in M. heratyi , with very long submarginal vein setae and three even longer parastigmal setae; costal cell with one complete row of ventral setae and additional ventral setae in apical quarter, with a row of 6 dorsal setae in apical half; speculum extending from middle of parastigma to be closed posteriorly by the complete subcubital setal track, with an occasional isolated ventral seta; five vague rows of short admarginal setae present but not exposed by speculum; basal cell sparsely setose, basal fold setose; cubital setal track ending at speculum. HW 7.0:2.4, not different from the typical pteromaline form.

Petiole transverse and small. Gaster 6.0:3.5, dorsally without rigid form and tending to collapse; first 5 gastral tergites with short medial posterior notch, sternites 1–3 each with a deep posterior incision; hypopygium ending 7.3 from gastral base (exceeding gastral apex, which is slightly upturned), with a small lateral­apical notch on each side and a smaller ventral­apical notch; ovipositor short: total length about 4.5, not exceeding gastral apex.

Males. Body (Figs. 7, 9) length 1.38–1.88 mm (7.5–10.2 in relative units). With some characters given in the above discussion of the genus. Differing from female in the characters noted in the generic discussion above. Also, scape 1.2–1.4:0.2; pedicel 0.4:0.3; EL 0.8–1.0; TL 0.3–0.4; genal concavity weaker and only about 0.15x MS; pronotal scrobe more sinuate, without an abrupt ventral ending; scutellum 1.6:1.8; much more bluntly pointed posteriorly; legs dark brown, with basal tarsomeres and extremes of tibiae lighter; PRF 1.6–2.2:0.3–0.5; MTF 1.9–2.6:0.3–0.5; petiole 0.4–0.5:0.3–0.4.

Variation. Only one female specimen known. Males showing no noteworthy variation.

Host: Unknown.

Distribution: Riverside County, northeast of Lake Skinner, all from coastal sage scrub habitat.

Etymology: After Lake Skinner, which is near the type locality.

Holotype Ψ USA: California: Riverside Co. Lake Skinner/Shipley Res. 2.8 mi NE Lake Skinner. 33°38 N 117°0 W. elev. 666 m. 17–20.ix.2000. Redak Lab, UCR. voucher: hym562 b6p3#23 (USNM). Allotype ɗ Riverside Co. Lake Skinner (NE End) 33° 36 7 N 117° 2 5 W. V­7/21 ­1996, J.D. Pinto. MT Coastal Sage Scrub. METU11, UNBURNED (USNM). 1 ɗ paratype Riverside Co. Lake Skinner (NE End) 33° 36 7 N 117° 2 5 W V­7/ 21 ­1996, J.D. Pinto. MT Coastal Sage Scrub (UCRC). 1 ɗ paratype Riverside Co. Lake Skinner (NE End) 33° 36 7 N 117° 2 5 W ca 1580’ v.2 /vi.4.1998 MT coastal sage scrub, J.D. Pinto (UCDC).

PLATE 1. Figures 1–3. Chlorocytus analis n. comb. lectotype female. Figure 1. Head and mesosoma dorsal view. Figure 2. Head and mesosoma lateral view. Figure 3. Metasoma dorsal view.

PLATE 2. Figure 4. Meximalus heratyi holotype female, head from dorsal view. Figures 6–8. Meximalus skinnerensis n. sp. allotype male. Figure 6. Antenna. Figure 7. Lateral habitus. Figure 8. Head and mesosoma dorsal view. Figures 9–10. Meximalus skinnerensis n. sp. holotype female. Figure 9. Face and antennae. Figure 10. Lateral habitus. Figures 11–12. Euteloida basalis n. sp. Figure 11. Allotype male antenna. Figure 12. Paratype female thorax, dorsal view.

PLATE 3. Figures 13–15. Euteloida skinnerensis n. sp. female. Figure 13. Propodeum of holotype; bcn = basal carina of nucha. Figure 14. Antennae of paratype, ventral view. Figure 15. Forewing of holotype. Figure 16. Euteloida subnigra holotype female forewing basal cell.

PLATE 4. Figures 17–21. Pseuderimerus burgeri n. sp. Figure 17. Holotype female dorsal habitus. Figure 18. Holotype female lateral habitus. Figure 19. Allotype male lateral habitus. Figure 20. Allotype male genitalia from ventral view. Figure 21. Melanistic paratype female.

Discussion. The differences between this species and M. heratyi are few, but sufficient to recognize them as different species. The differences in femoral length/width between the two species are more than that exhibited by most pteromaline genera, where pro­ and/ or metafemoral differences of this magnitude constitute a relatively useful character helping to distinguish certain groups of genera.

Euteloida Bou č ek

We have found several specimens, of this previously monospecific genus, from Southern California, where it appears to be relatively common. This constitutes the first discovery of males of the genus and the first reports of the genus aside from the holotype of E. subnigra .

Bouček (1993) described Euteloida with little comment on its placement and differences from other genera. With the discovery of a new species, the list of diagnostic characters of the genus relative to similar genera can be refined.

Males. Flagellum (Fig. 11) with few, irregularly placed longitudinal sensilla but with many curved flagellar setae. Club not acuminate, with symmetrical sutures and no conspicuous sensory areas.

Both sexes. The deep lateral gap between the pronotal collar and mesoscutum (Fig. 12) was cited by Bouček as a generic character, but we have found this character to be only occasionally useful and frequently misleading because it can be affected by the position of the body at death. Additionally, the extreme reduction or lack of a posterior smooth strip of the pronotal collar seemed to be a significant character, but the smooth strip is conspicuous and relatively long in males and small females. Nucha (Fig. 13) with a weak basal crosscarina merging smoothly with posterior remnants of plicae; variably emarginate posteriorly, not always deeply so.

Discussion. Euteloida is similar to some other pteromaline genera having the propodeal plicae smoothly merging with an isolated basal cross­carina of the nucha but lacking a distinct median carina, such as the Palearctic Lyubana Bouček. However , Lyubana has a genal carina, a narrowly and deeply incised clypeal margin with a pair of sharp and narrow denticles, and flagellum with 3 anelli and 5 funicular segments. Each of these characters can be variable between closely related pteromaline genera and even within some genera, such that it is difficult to discern a clear phylogenetic pattern using them. The Australasian genus Nuchata Bouček is similar to Euteloida in claval and propodeal form, including the bump­like callar elevations. Nuchata differs from Euteloida in having a faint occipital carina, a strong genal carina, and a longer nucha relative to the rest of the propodeum. Sceptrothelys Graham is also similar in claval form and in general reduction to Euteloida , but has a much different propodeum with a long, cylindrical nucha, strong plicae extending from anterior plical pits to near nuchal apex, and no nuchal cross­carina. Norbanus Walker and some species groups of Homoporus Thomson , along with several related genera, are similar to Euteloida in having a relatively acarinate propodeum that is uniformly alveolate, but they have a distinct claval spicule in females and differ in a number of other characters, especially in having a propodeal costula and lacking posterior plicae (when propodeal carinae are discernable), such that they would not seem to be especially close to Euteloida . We suspect that the basal cross­carina of the nucha in Euteloida is homologous with the more distinct nuchal carina found in most pteromaline genera such as Mesopolobus , and that the apparent lack of separation between it and the plicae is due to the presence of these carinae only across the base of a convex nucha and their lack of connection to any other carinae or to either propodeal margin. This state constitutes a distinction between Euteloida and nearly all other pteromaline genera. Unfortunately, this carina is not easily visible in many specimens of Euteloida .

The revised diagnosis of Euteloida can be summarized as follows: flagellum with 2 typical anelli; club with asymmetrical sutures in females and apical claval segment with two distinct ventral micropilose areas; genal carina absent; clypeal margin very shallowly emarginate; left mandible with 3 denticles, the right with 4; pronotal collar not carinate; notauli incomplete; median carina and plicae incomplete; nucha convex but short, hardly projecting beyond supracoxal flange at metacoxal bases; 1 metatibial spur.