Gyascutus (s. str.) allenrolfeae (Verity) Nelson, 2000

Nelson, G. H., 2000, A revision of the subtribe Hippomelanina, part II: Gyascutus (Gyascutus) LeConte (Coleoptera: Buprestidae), Journal of Natural History 34 (12), pp. 2251-2292 : 2284-2287

11. Gyascutus (s. str.) allenrolfeae (Verity) , comb. nov.

(®gures 13, 23, 41, 44, 45, 46, 50)

Hippomelas allenrolfeae Verity, 1978: 161 .

Diagnosis. Colour brassy-grey; males average 16.8 mm long, females 19.5 mm; width between eyes 1.4 Ö width of eye in dorsal view; antennae reaching to near posterior angles of pronotum when laid alongside in male, to posterior third in female; pronotum widest at posterior margin; pronotal disc a mixture of smooth raised callosities and punctate areas; elytra costate; male genitalia moderately broadly lanceolate (®gure 41).

Redescription, holotype male. Head width between eyes 1.4 Ö width of eye in dorsal view; front ¯at, depressed between antennal ridges, surface densely setopunctate along eyes and in depression on lower front, elsewhere punctures less dense with irregular, raised, longitudinal smooth areas in midline and forming inverted chevron on front; clypeal margin broadly, shallowly, arcuately emarginate; antennae reaching to near posterior angles of pronotum when laid alongside; serrate from antennomere 4±10, antennomeres ¯attened with outer margins subparallel, gradually narrowed and shortened apicalward, 11 rectangularly notched at outer angle (®gure 23a).

Pronotal width 1.6 Ö length, widest at posterior margin; lateral margins carinate in posterior half, ¯aired at posterior margin, then subparallel to middle and converging to narrowest at anterior angles; anterior margin shallowly arcuately lobed at middle; posterior margin with distinct emarginate median lobe; disc convex, slightly ¯attened in middle posteriorly with transverse impression behind anterior margin and more deeply impressed along posterior margin half way to lateral margin; surface a mixture of raised smooth callosities and punctate areas, callosities predominant medially becoming smaller laterally, punctures bearing inconspicuous, short, semi-recumbent, white, hair-like setae chie¯y laterally. Scutellum small, roundly transverse, glabrous, impunctate.

Elytra as wide as pronotum at base; lateral margins subparallel in basal third, then feebly and ®nally more strongly converging to bidentate, emarginate apices, margins serrulate apically; disc with non-prominent sutural, scutellar and four discal costae, surface densely, ®nely punctate between costae with some transverse strigae toward base; moderately clothed by short, semi-recumbent, white, hair-like setae.

Ventrally, densely punctate laterally, somewhat scabrous on proepisternum and abdominal sterna, punctures sparser medially, punctate areas densely clothed by short, recumbent, white, hair-like setae with pulverulence; prosternum with anterior margin truncate, disc weakly depressed anteriorly with de®nite oval depression before procoxal cavities; prosternal process smooth with irregularly punctate midline and setose sulcus along margin; metasternum with midline sulcus; protrochanter with small tooth on inner margin; protibia slender, arcuate with several teeth along inner margin on apical half; meso- and metatibia slender, straight; metatarsomere 1 subequal in length to 2 1 3, longer than 5; last visible abdominal sternum with serrulate submarginal ridge, apex weakly, roundly truncate, posterolateral angles dentate. Length, 20.5 mm; width, 7.5 mm.

Male genitalia (®gure 41).

Redescription, allotype female. DiOEers from male as follows: antennae shorter, reaching posterior third of pronotum when laid alongside, antennomere 11 with smaller notch (®gure 23b); protibia straighter, without teeth; metatarsomer e 1 shorter than 2 1 3; apex of last visible abdominal sternum roundly crenulate. Length, 20.0 mm; width, 7.5 mm.

Type locality: California, Imperial Co., 1 mile SE Niland Marina.

Type material. The holotype lof Hippomelas allenrolfeae Verity (CASC #12978) is labelled as follows: Calif., Imp. Co., 1 mi SE Niland Marina July 6, 1973 (h)/on Allenrolfea occidentalis (h)/collector G. Walters (h)/(red label) HOLOTYPE Hippomelas allenrolfeae Verity (h)/ California Academy of Sciences Type (p) 12978 (h).

Variation. The 50 males and 47 females examined reveal that the colour ranges from greenish copper to dark green. Specimens from the north-eastern end of Salton Sea in Riverside Co. have the elytral costae greatly reduced or absent; whereas, those from Bahia Santa Maria , Baja California Norte have the costae well developed. Males vary from 12.9 to 21.5 mm long (mean 5 16.8 mm, n 5 50) and 4.0± 8.1 mm wide (mean 5 6.0 mm, n 5 50); females from 12.0 to 23.6 mm long (mean5 19.5 mm, n 5 44) and 4.4±9.0 mm wide (mean 5 7.4 mm, n 5 44).

Distribution (®gure 50). It has been found in alkaline ¯ats associated with its host plant, Allenrolfea at the following sites. USA, Arizona ÐYuma Co., Adair Park. California ÐImperial Co., Hwy. 111, near Niland Marina, Luento and Oten Washes; 1.5 km SE Niland Marina; Hwy. S32, along old river channel; Salton Sea, Red Hill Marina and Campground. Riverside Co., 1.5 km S Mecca, Hwy. 111. Mexico, Baja California Norte Ð 38.5 km S San Felipe, Bahia Santa Maria.

Biology. The larvae feed in the roots and crowns of Allenrolfea occidentalis (Wats.) Kunz. (®gures 44±46) and adults have been collected on this plant from late June to August.

Comparisons. As Verity (1978) pointed out, this species is not closely similar to any other species in this subgenus. Its subparallel form is similar only to some atypical forms of G. planicosta (LeC.), but is easily distinguished by its blackish colour with brassy tint and the lanceolate form of its male genitalia.