Graphops cavani Clark and Heninger, 2016

Clark, Shawn M. & Heninger, Amanda J., 2016, A Flightless New Species ofGraphopsLeconte, 1884 (Coleoptera: Chrysomelidae: Eumolpinae) from Utah, USA, The Coleopterists Bulletin 70 (1), pp. 171-176 : 171-176

Graphops cavani Clark and Heninger , new species

( Figs. 1 , 2, 3 )

Diagnosis. Graphops has a setose dorsum, as well as deep grooves on the head, these being nearly adjacent to the eyes behind, but extending diagonally away from the eyes in the frontal area ( Fig. 1c ). This combination of characters is not found in any other eumolpines occurring in the United States. In some specimens, especially rubbed specimens, the dorsal setae are inconspicuous, but they are nearly always evident in lateral areas. Graphops cavani is large (4.0– 6.9 mm long) and bright metallic green, and the anterior edge of the prothorax is distinctly toothed behind the eyes ( Fig. 1d ). This combination is found in no other species in the genus. Graphops comosa Blake, 1955 is also large, and some specimens have a weakly developed tooth behind each eye; however, the color is black, with only a weak metallic luster. Using the identification key provided by Blake (1955), this new species would best fall out at couplet 14. However, in view of the reduced elytral humeri, a few users might identify it as Graphops barberi Blake, 1955 , in couplet 1. In either case, G. cavani is readily recognizable based on the characters mentioned above.

Description. Male Holotype. Body oblong oval, distinctly narrowed between prothorax and elytra, 5.2 mm long, 2.5 mm wide ( Fig. 1a, b ). Color black, with strong metallic green luster; white, stout, appressed setae present on head, thorax, elytra, abdomen, antennae, and legs, although sparse (possibly rubbed off) on discal areas of pronotum and elytra. Punctation dense and deep on pronotum, dense and mostly striate on the elytra.

Head with deep sulcus beginning between eyes, but laterad of meson, extending around upper margin of each eye and thence around hind margin of eye; shallow, transverse impression present in mesal area between eyes; shallow mesal fovea on frons; white pubescence conspicuous, although sparse near hind margin of vertex; occipital area well-rounded; punctation distinct, dense; interspaces strongly alutaceous, but with frons shinier than vertex; clypeus densely punctate, with apical margin broadly angulate. Antennae extending slightly beyond humerus; antennomere 1 about twice as long as broad, distinctly curved; antennomere 2 slightly longer than broad, distinctly narrower than antennomere 1, distinctly broader than antennomere 3; antennomeres 3–6 subequal in length, each more than twice as long as broad, sparsely setose; antennomeres 7–11 broader than preceding antennomeres, about as broad as antennomere 1, densely covered with short pubescence, each equipped with whorl of long setae near apex.

Prothorax not quite as long as wide; sides rounded; basal edge with distinctly raised bead; lateral and anterior edges without beads; disc somewhat shiny, although distinctly alutaceous; discal punctures deep, dense, rather coarse, separated on average by a distance subequal to their diameters; setae dense laterally, absent (possibly rubbed off) in discal area. Scutellum rather densely, finely punctate, pubescent, semicircular, rounded behind.

Elytra apparently fused along suture, rather shiny, although distinctly alutaceous, dark metallic green; humeri small, very poorly developed; lateral and apical areas rather densely setose; basal and discal areas nearly asetose (setae possibly rubbed off); striate punctation well-developed, closely spaced, becoming much finer beyond middle, with punctures in basal half much larger than those of pronotum, with punctures in apical half much smaller than those of pronotum; striae in basal half mostly separated by a distance subequal to diameter of puncture; punctures in basal half within each row mostly separated by a distance less than their diameter; punctures in distal half mostly separated by a distance greater than diameter of puncture, both within each row and between rows. Metathoracic wings (of paratypes from type locality) reduced.

Ventral areas metallic green, densely covered with appressed setae nearly throughout. Anterolateral corner of prosternum forming distinct tooth behind eye ( Fig. 1d ); prosternum anterior to coxa, about as long as width of antennomere 1; prosternum between coxae wider than transverse diameter of coxa; prosternal process much broadened behind coxa, meeting propleuron laterally; mesopleuron asetose, impunctate, alutaceous; mesosternum about twice as wide as long, densely

(arrow indicates position of tooth).

setose, coarsely, densely punctate; metepimeron and metepisternum very densely covered with appressed white setae; metasternum very short, with mesal length only slightly greater than that of mesosternum; metasternal surface setose, densely, rugosely punctate, with shallow, longitudinal, mesal groove, with distinct, transverse, preapical sulcus. Legs dark metallic green; femora each without ventral tooth; each tibia with very dense patch of setae near apex; tarsal claws with short, acute, basal tooth. Abdomen densely punctate and pubescent; posterior tergite subtriangular, rounded behind, coarsely punctate and setose in posterior half, nearly impunctate and asetose in anterior half, without mesal groove. Aedeagus (of paratypes from type locality) as in 4.9–6.9 mm long and 2.7–3.5 mm wide. In a few specimens, the metallic luster is bluish or purplish, rather than the usual green. In some specimens, the pronotal punctures, especially those in lateral areas, are partially confluent, forming ill-defined rugae, and, in some specimens, the pronotal punctures are narrowly absent along the meson. Most specimens are nearly without setae in the discal areas of the pronotum and elytra, the setae being dense only in the marginal areas. Apparently, the discal setae are easily rubbed off. However, in a few specimens, discal setae are present. Females are very similar to males, but, as noted above, are of larger average size. The front and middle tarsi are slightly narrower in the female than in the male, and some of the ventral tarsal setae of the male are spatulate, this noticeable only under high magnification. The mesal area of first abdominal ventrite of the female tends to be slightly convex, while this area tends to be flat or even slightly concave in the male. The abdominal apex is slightly rounded in most females and slightly truncate in most males. The spermatheca is as in Fig. 2c.

Material Examined. Holotype: “ USA, Utah, Emery Co., / Little Flat Top , Rt. 1010, / 38.5392°N, 110.4902°W, / 5600 ft., 20-VI-2014, / S. M. Clark & A. J. Gilbert // host: / Oenothera pallida / var. pallida / Douglas ex Lindl.” (male, BYUC).

Distribution. As evidenced in the Material Examined section above, the range of this species is apparently very limited. We have seen specimens from only three counties, all in southern Utah.

Etymology. The species epithet of these insects honors Daniel J. Cavan. He is a good friend, an outstanding collector, and the first to record a plant association on specimen labels of the material examined.

Habits. Adults of this new species are associated with Oenothera pallida Lindley (Onagraceae) , which grows in deep sand ( Fig. 3 ). Most likely, larvae feed on roots of the same plants. Whereas many eumolpines are most likely to be found at night, this species is very active in bright sunlight. Also, unlike many leaf beetles ( Chrysomelidae ) that drop to the ground when disturbed, these beetles tend to cling to the host plants. Specimens were more successfully collected by hand-picking than with a sweep net. In spite of the tendency to cling, many individuals were observed on the sand. They scurried between plants, raised high on “tip toes” in a manner similar to that of some tenebrionids. They were never observed flying. In spite of the fact that specimens have been collected as early as 18 May and as late as 27 August, they are not easily found throughout this period. We visited areas known to be inhabited by this species, at times of the year when series had been collected in previous years, but we were unable to find even a single specimen. Apparently, the activity of the insects is closely tied to rainfall. They are active only after rain sufficient to enable a flush of the host plants.

Comments. Graphops cavani is clearly flightless. This is evidenced by the reduced humeri, the comparatively short metasternum, and especially the reduced metathoracic wings. The elytra are apparently fused along the suture; at least, they did not separate from each other, even in specimens in which we disarticulated the elytra from the thorax. Although most species of the genus lack such characters associated with flightlessness, other possibly flightless species are G. barberi and G. comosa .

Figures

Fig. 1. Graphops cavani. a) Dorsal habitus, b) Lateral habitus, c) Head, frontal view, d) Prothorax, lateral view

Fig. 3. Habitat of Graphops cavani (28 km NNE Hanksville on Hwy. 24, Emery County, Utah).