Agrilus interstitialis Hespenheide and Westcott

Hespenheide, Henry A., Westcott, Richard L. & Bellamy, Charles L., 2011, Agrilus Curtis (Coleoptera: Buprestidae) of the Baja California peninsula, México, Zootaxa 2805, pp. 36-56 : 41

Agrilus interstitialis Hespenheide and Westcott , New Species

(Figs. 8–10)

Description. Holotype male: robust, proportionately broad, in cross-section moderately flattened above, convex below, 2.50 mm long, 0.70 mm wide; black throughout with golden reflections, except more bronzy on elytra; setae short, recumbent, and inconspicuous throughout, denser in spots in anterior depressions of elytra and in narrow sutural stripes on posterior 3/4 of elytra, very dense on upper 1/2 of posterior coxae and upper posterior angle of metasternum, moderately dense and semi-erect on prosternal process, moderately dense and recumbent on upper portions of abdominal ventrites 3–4.

Head with front convex with narrow shallow depression along midline on basal 1/2 above antennal insertions, surface weakly punctate; epistoma very narrow, width <1/5 of distance between inner margins of eyes, raised, and slightly concave between antennal insertions below fine transverse carina joining upper margins of antennal insertions, ventral margin nearly transverse; eyes oval; antennae compact, serrate from antennomere 5, antennomere 5 weakly triangular, antennomeres 6–11 more strongly rounded-triangular.

Pronotum slightly narrower than elytra at posterior margin, with sides shallowly rounded outward to middle, then narrowing to apex; marginal and submarginal carinae narrowly separated at apices then converging and joining at base when viewed from side; from above anterior margin produced as broadly rounded lobe; basal margin undulate, angulately emarginate at middle of each elytron, slightly emarginate before scutellum; disk regularly convex, with broad shallow depression at base and extending along lateral margins; prehumeral carinae absent; surface indistinctly finely concentrically rugose. Scutellum rounded-triangular, barely raised, shagreened.

Elytra with lateral margins nearly parallel for basal 1/2, widest slightly beyond middle then narrowing to broadly, separately rounded and minutely toothed apices; disk shallowly convex in cross section, each elytron with small, moderately strong oval depression at base, costate with narrow, shallow setose sutural depression on posterior 3/4; surface imbricate, more strongly so on basal 1/2.

Prosternum with narrow prosternal process, sides parallel between coxae, apex rounded; prosternal lobe nearly transverse, indistinctly broadly emarginate at middle. Posterior coxae with posterior margin nearly straight, upper exterior angles quadrate. Abdomen with short, narrow lateral depression indicating suture between ventrites 1 and 2, posterior margin of ventrite 1 very narrowly deflexed at middle, ventrites 1–5 regularly convex, dorsal portions very narrow, equal in width, not more setose than lateral portions. Legs and tarsi difficult to observe, metatarsi missing. Genitalia as in Figure 10.

Allotype female: as male except 2.80 mm long, 0.80 mm wide; setae on prosternal process recumbent; metatarsomere 1 equal in length to next three combined, tarsal claws on protarsomere cleft with very short blunt inner tooth.

Type material. Holotype: México: Baja California Sur, Baja Calif. Sur, 1 mi N, 4–1/ 2 mi W San Jose del Cabo, 290m, 20-VII-1977, Dozier & Westcott ( CAS). Allotype: same data as holotype ( RLWE). Paratypes: México: Baja California Sur, Bahia Concepcion, Playa El Coyote , 6-VI-1974, R.L. Westcott (F, RLWE), La Paz, km. 45 W, 8-VI-1975, E.L. Sleeper (F, CLBC), 20 km S of La Paz, 1-IX-1994, R. Morris (M, F, RLWE), San Pedro, 1- IX-94, R. Turnbow (F, RLWE), Playa El Coyote, 26 km SSE Mulegé, 25-VII-77, beating mesquite, Prosopis glandulosa var. torreyana, Dozier & Westcott (F, RLWE). Paratype also to be deposited in CHAH.

Host. One specimen was collected on Prosopis glandulosa var. torreyana .

Etymology. The name refers to the interrupted elytral vittae.

Discussion. This species is similar to Agrilus ventralis Horn and probably related to it, but A. ventralis is larger (> 3.5 mm long), the middle of the posterior margin of second abdominal ventrite is conspicuously extended as a broad, somewhat deflexed projection, the posterior margins of ventrites 3–4 less conspicuously deflexed, the sutural stripes of setae on the elytra are complete from the anterior depressions to near the apices, and the front is glabrous except for a narrow medial stripe of short setae on the ventral 1/3. This species is also similar to A. cercidii Knull , but in that species the sutural stripes of setae on the elytra are interrupted at both the base and at the middle, the pronotum is more deeply depressed at the medial basal margin, the marginal and submarginal carinae of the pronotum are more widely separated and do not meet at the posterior angles, and it differs in other characters. This is one of the smallest species of Agrilus : males in the type series measure 2.50–2.70 mm long (mean = 2.60 mm, n = 2 specimens), and females measure 2.75–3.37 mm long (mean = 3.04 mm, n = 6 specimens). We prefer to designate a male as a holotype, and chose the better of the two imperfect male specimens as the holotype.