Tragidion agave Swift and Ray

Swift, Ian & Ray, Ann M., 2008, A review of the genus Tragidion Audinet-Serville, 1834 (Coleoptera: Cerambycidae: Cerambycinae: Trachyderini), Zootaxa 1892, pp. 1-25 : 7-9

Tragidion agave Swift and Ray , new species

( Figs 1 A–B, 5A–B, 7A)

Description. As in Figs 1 A, B. Male: form, moderately sized, elongate, red-brown integument with tan elytra. Head: shining, red to red-brown, shallowly punctate throughout, except genae and labrum which are more densely punctate; vertex moderately elevated; antennal tubercles prominent, impunctate, broadly rounded, projecting posteriorly; pubescence throughout short (~ 2 mm), erect, sparse, ranging from black to brown; eyes finely faceted with convex ommatidia, five wide at the narrowest constriction of the antennal insertion; antennae with 11 antennomeres, entirely red-brown, not annulated, antennomeres 3–10 with sparse cluster of short, appressed, black setae around circumference of apex; scape subconical, tapering anteriorly, widest at apex, sparsely punctate and pubescent, with short, appressed, brown and black-tipped setae, less than twice the width of antennomere 2 at apex; antennomere 2 moderately punctate; antennomere 3 very sparsely punctate and pubescent, the remaining antennomeres impunctate, but with sparse, very short, appressed, black setae; antennomeres 7–10 entirely carinate on lateral face, 3–6 subcarinate, 4–10 with apico-lateral spine short, projected sublaterally, 4–6 increasing in size of spine, 6 the largest, 7–10 decreasing in spine size; antennomere 11 strongly apendiculate, linear, filiform; antennae surpassing the elytral apices by at least three whole antennomeres. Pronotum: shining, red-brown, sparsely pubescent, coarsely, densely punctate, wider than long, narrower than elytral humeri; punctation along anterior margin and lateral face coarse, deep, not confluent, primarily in association with gland pores; medial callus expanded posteriorly and roughly tapering to a point anteriorly, glabrous in the central portion and very sparsely, finely punctate along outer margin; two peripheral, smaller, rounded calli of similar vestiture surrounding the medial callus on either side; lateral pronotal tubercles pronounced, forming a rounded spine, posteriorly recurved, glabrous, projecting out to the width of the elytra at humeri; two additional, rounded, lateral calli situated anteriorly to the pronotal tubercles, 1.5mm in diameter; venter of pronotum very coarsely, densely punctate; prosternal process parallel sided, attaining the posterior edge of the coxae, weakly bilobed, not expanded at apex, narrower than the coxa; procoxal cavities open. Elytra: tan, at most 2.5 × wide as long at humeri; densely pubescent with short, appressed hairs distributed evenly throughout elytra, a very narrow band of black and brown pubescence present at the basal margin; four feeble striae on each elytron, not raised, even with the surface of the elytra; the stria closest to the suture originating medially from the base of each elytron, extending apically at an obtuse angle toward the suture, meeting the suture at a point ¼ from the base and extending parallel to the suture, often so close as to be obscured; second stria originating from the same point as the first, extending apically in a straight line to ¼ of apex, then curving to the suture and terminating; third stria originating from a point slightly lateral to the previous two, extending apically straight down the elytron and terminating at ¼ to apex; fourth stria originating at a point on the lateral side of the elytron just above the epipleura, then extending below and curving around the epipleura along the lateral margin of the elytron, terminating before the apical ¼; elytral apices obtusely, broadly rounded, elytra generally parallel sided; scutellum equilaterally triangular, dark red-brown, moderately pubescent with appressed setae slightly longer and thicker than elytral pubescence. Legs: redbrown; metafemora stout, clothed on the dorsal surface with appressed, black setae, apex of metafemora broadly rounded; metatibae stout, not sinuate in lateral view, gradually increasing in size apically; moderately clothed in short, erect, black and brown pubescence increasing in density apically, two short metatibial spines present at apex; all tarsi broad, first metatarsomere shorter than the following two combined, second metatarsomere wider than long, distinctly shorter than the third, metatarsal claw inserted to half its length into the first tarsomere. Ventral surface: red-brown, moderately pubescent throughout, not obscuring the surface, pubescence of two types: sparse, long, erect, brown flying hairs, and moderately dense, short, appressed, brown to black setae; mesosternal process broad, expanding apically slightly around the mesocoxae, bilobed, not attaining the posterior end of the mesocoxae; first abdominal ventrite broad, punctation sparse, fine, well separated; the remaining ventrites more densely, coarsely punctate, fifth ventrite trapezoidal, weakly emarginate at middle. Size: 20.50 to 28.76 mm; mean 24.72 mm; n = 29.

Female: form, moderately sized, elongate, black integument with yellow-orange elytra. Generally similar in gross morphology to male, but differing in the following aspects: Head: more densely pubescent, integument black to very dark brown; antennae short, attaining the elytral apices or nearly so; basal antennomeres annulated in orange. Pronotum: more densely pubescent, obscuring the surface; pronotal punctation fine, shallow, lateral areas lacking coarse punctures associated with gland pores; lateral pronotal tubercles prominent. Elytra: yellow orange, with very narrow black basal band at the basal margin of the humeri. Legs: black, some tarsi red-brown. Ventral surface: black, fifth ventrite expanded apically with setal brush. Size: 20.38 to 25.65 mm; mean 22.97 mm; n = 14.

Diagnosis: Tragidion agave is most similar to T. armatum , but possesses several unique characters in the males that will allow for its distinction. These include: the uniformly brown antennae, which exceed the elytral apices by at least three whole antennomeres, T. armatum having annulated antennae, which exceed the elytral apices by no more than two antennomeres; the red-brown integument and tan elytra, T. armatum having a black integument and yellow orange elytra; the sparsely pubescent pronotum with short setae, which is more densely pubescent with longer setae in T. armatum . It can further be separated by the following minor, more variable characters: larger average size; more strongly pronounced and more posteriorly decurved lateral pronotal tubercles; and the subcarinate sixth antennomere.

The female of T. agave is very similar to the female of T. armatum , and salient diagnostic characters are few. In general, the antennae are longer and extend to the apex of the elytra or nearly so, whereas in T. armatum females, the antennae extend to no more than % the elytral apices. The basal antennomeres are usually annulated in orange whereas in T. armatum , they are usually entirely black. In addition, the lateral pronotal tubercles are more pronounced in T. agave than in T. armatum .

Tragidion agave is also similar to T. gracilipes Linsley ; both species having non-carinate elytra and the antennae of males exceeding the elytral apices by three antennomeres or more. However, T. gracilipes has narrower tarsi, in which the first tarsomere is longer than the following two together, and the second tarsomere longer than broad and distinctly more elongate than the third, a larger scape that is 2 × the width of the second antennomere at the apex, as well as a black integument and yellow-orange elytra. Overall, T. gracilipes has a smaller mean size range, and is less robust.

Type material: Holotype male from USA, California, Riverside County, 7-level hill, V-29-1971, F. T. Hovore, coll. ( USNM). Allotype female same data as holotype ( USNM). Paratypes from: one male: California, San Bernardino County, Desert Springs, 10 June 1962, GH Nelson, collector ( JWPC); one male: California, Riverside County, Seven-level Hill, 27 July 1973, CE Langston, collector; one male: California, San Diego County, La Pliera Valley, 0 1 July 1911, GHG, collector ( MCZC); one female: California, Imperial County, Mountain Springs, 0 5 June 1965, DS Verity, collector ( DSVC); 12 males and two females: Mexico, Baja California, 6 miles east of Rumerosa, 0 4 July 1965, DS Verity, collector ( DSVC); two males: California, Santa Rosa Mountains, 2000 feet, 10 June 1966, G Walters, collector ( USNM); 11 males, six females: California, Riverside County, 7-level hill, various dates in June and July, 1968, 1969, and 1971, EF Giesbert, collector ( FSCA); one male, one female: California, Mountain Springs, 0 3 July 1965, GH Nelson, collector ( FSCA); one female: Mexico, Baja California, 6 miles east of Rumerosa, 0 4 July 1965, G Walters, collector ( FSCA); 10 males, 14 females: California, Riverside County, 8 miles west of Palm Desert, various dates in June of 1979 and 1980, J Cope, collector; five males, six females: California, Riverside County, 7-level Hill, various dates in June of 1982, 1994, and 2004, J Cope, collector.

Distribution ( Fig. 7 A). Mountains of southern California including the San Jacinto, Santa Rosa, and Laguna Mountains, as well as the San Pedro Martir Mountains of northern Baja California. Within this range, it is found in desert scrub habitats dominated by Agave deserti, Juniperus californica , Quercus john-tuckeri , Encelia farinosa , and Isomeris arborea .

Ecology. Larvae feed primarily in Agave deserti throughout its range. The habits of larvae and adults are similar to T. armatum as detailed by Chemsak and Powell (1966).

Etymology. The species epithet refers to the host plant of this species. It is a noun in apposition.

Figures

FIGURE 1. Dorsal habitus photos of Tragidion spp. A, Tragidion agave (male); B, T. agave (female); C, T. annulatum (male); D, T. annulatum (female); E, T. armatum (male); F, T. armatum (female).

FIGURE 7. Distribution map of Tragidion spp. A, Tragidion agave; B, T. gracilipes; C, T. annulatum; D, T. deceptum; E, T. densiventre; F, T. auripenne.