Agrilus howdenorum Hespenheide

Hespenheide, Henry A., 2008, New Agrilus Curtis species from mistletoe in México (Coleoptera: Buprestidae), Zootaxa 1879, pp. 52-56 : 54-56

Agrilus howdenorum Hespenheide , new species

( Figs. 4–7 )

Description. Holotype male: Moderately robust, flattened above, more convex below in cross section, 6.8 mm long, 1.8 mm wide; more or less uniformly purplish-red throughout, except darker purple in basal depression of pronotum and elytra beneath yellow setae with coppery reflections, front and anterior faces of anterior femora metallic olive-green; front and above largely glabrous except for irregular patch of pale yellow setae for 3/5 length of elytra beyond anterior 1/4 ( Fig. 4 ); pale yellow setae recumbent, inconspicuous, and more or less uniform beneath, except slightly denser and semi-erect on prosternal process, on dorsal portions of ventrites 1–4, and on upper lateral portions of ventrites 1–2, and covering of ventrites 3–4 except along midline ( Fig. 5 ).

Head with front convex, narrowly depressed along midline above middle, surface minutely punctate and shagreened; epistoma between antennal insertions 1/3 width of distance between inner margins of eyes, slightly emarginate below, eyes oval; antennae distinctly serrate from antennomere 4, antennomeres 4–11 triangular.

Pronotum slightly narrower than elytra at posterior margin, with sides shallowly expanded outward then gently rounded to apex; marginal and submarginal carinae slightly undulate, separated for entire length, widely so in front and converging toward base when viewed from side; from above anterior margin broadly rounded; basal margin angulately emarginate at middle of each elytron, transverse before scutellum; disk very irregular, with strong basal depression and weaker anterior depression along midline, smaller depressions lateral to anterior depression, and strong oblique depressions in front of prehumeral carinae to lateral margins; prehumeral carinae not conspicuous, 1/4 length of pronotum, angling medially from posterior angles; surface coarsely, irregularly rugose, rugae especially distorted at midline. Scutellum pentagonal with transverse ridge.

Elytra subequal in width at humeri and beyond middle with lateral margins indistinctly emarginate between, apices broadly, separately rounded, coarsely toothed and slightly emarginate between teeth; disk relatively flat, humeri narrow and prominent, each elytron with broad, shallow depression at base and irregular costa along suture to setal fascia, then stronger to end of fascia; surface transversely imbricate-punctate, more coarsely so on basal 1/4, more polished beneath yellow setae.

Prosternum with sides of prosternal process slightly emarginate between coxae, broadly rounded at apex, prosternal lobe shallowly emarginate. Posterior coxae with posterior margin shallowly emarginate, upper angles sharply acute. Abdomen with distinct depression between ventrites 1 and 2 at sides, ventrite 5 broadly rounded at apex; posterior dorsal portion of ventrite 1 distinctly wider than ventrite 2. Metatarsomere 1 slightly longer in length than next two combined, tarsal claws similar on all feet, cleft with short inner tooth. Genitalia as in Figure 6 .

Allotype Female: As holotype except 6.7 mm long, 1.9 mm wide; front between eyes and anterior faces of anterior femora purplish-red; antennae more compact.

Holotype ( CMNC): México: Oaxaca, 5 mi SW Oaxaca, 4700’, 4.viii.83, R. Anderson/W. Maddison, Acacia thorn scrub, on mistletoe. Allotype ( CMNC): same data as Holotype. Paratypes: México, Oaxaca, Hwy 175 10 km NE Oaxaca, 1800 m, 11.VI.1979, H. & A. Howden (to be deposited in CMNC) 7 km NNW Diaz Ordaz, 2200 m, N17.00 W96.26, 11.VII.1992, C.L. Bellamy, beating mistletoe (1, CLBC), 7 km NW Diaz Ordaz (road to Villa Alta), 2170 m, N17°01’ W96°28’, 18.VII.2003, C.L. Bellamy CLB 846, beating mistletoe (2, CLBC).

Etymology. Named in honor of coleopterists Henry and Anne Howden, collectors of one of the paratypes.

Discussion. The holotype is the unique male; females measure 6.0– 7.5 mm long (mean = 6.9 mm for 5 specimens). Both this and the preceding species are apparently related to but rather different from Agrilus turnbowi Nelson from Texas which also uses Phoradendron as a host. All three are generally purplish-red in coloration, have a deep medial depression at the base of the pronotum, a more or less complex pattern of golden setae on the middle half or more of the elytra, and similar male genitalia. As can be seen in the photograph of Agrilus howdenorum on its host plant ( Fig. 7 ), the golden setae are similar in coloration to the leaves of Phoradendron and may serve to make the three species less conspicuous by disruptive coloration. Agrilus turnbowi differs from the two Mexican species in having the elytral setae continue to the base of the elytra, but broadly interrupted beyond the middle by an oblique glabrous band, and by having the golden setae on the abdomen restricted to small patches on the dorsal portion of ventrite 1 and lateral portions of abdominal ventrites 3 and 4. Agrilus howdenorum is superficially very similar to A. andersoni but differs in overall color, is larger, and has a glabrous, shagreened front and a different pattern of setae on elytra.

Figures

FIGURE 7. Agrilus howdenorum adult on mistletoe host plant near Diaz Ordaz, Oaxaca, México. The golden setae on the elytra are similar in color to the leaves of the mistletoe and may function as a disruptive color pattern. Photograph by C. L. Bellamy.

FIGURES 4 – 6. Agrilus howdenorum Hespenheide: 4. dorsal habitus; 5. lateral habitus (scale bar indicates 2.0 mm); 6. genitalia of male (scale bar indicates 0.5 mm).