Zorion opacum Sharp

Schnitzler, Franz-Rudolf & Wang, Qiao, 2005, Revision of Zorion Pascoe (Coleoptera: Cerambycidae), an endemic genus of New Zealand, Zootaxa 1066, pp. 1-42 : 34-35

Zorion opacum Sharp

(Figs. 21, 24)

Zorion opacum Sharp, 1903: 109 . – Broun, 1909: 147; Aurivillius, 1912: 156; Blair, 1937: 265; Macfarlane, 1979: 64 –70; Early et al., 1991: 10 –24; Emberson, 1998:46.

Diagnosis

Zorion opacum can be distinguished from all other Zorion species by the dorsally matte body surface, which gives the head, prothorax and elytra a silky dull appearance. All other Zorion species have glossy elytra.

Redescription

Body length: Male 3.18–6.96 mm, female 3.78–7.12 mm.

Colour: Body golden brown, with a pale ivory spot on each elytron (Fig. 21). Elytral spot variable or absent. Head and pronotum dark brown, base of elytra dark brown about half way towards apex elytra becoming light brown. Tip of mandibles black. Scape and pedicel golden brown; antennal segments 3–7 or 3–8 pale brown at base but gradually becoming dark brown towards apex; antennal segments 8–11 or 9–11 dark brown or pale brown. Pro­ and mesocoxal cavity bounded by dark edge; trochanter and apex of coxa creamy golden brown; base of femur whitish or pale brown, not bearing a dark ring at beginning of femoral club as in Fig. 3 ; tibia and tarsi golden brown throughout. Abdominal segments dark brown but often the last two visible segments light brown.

Structure: Head, prothorax and elytra silky dull, matt surface dorsally, body shiny ventrally. Pronotum with slightly wrinkled surface. Females with hairs on anterior epipleural fold; males usually without such hairs. Elytral apex rounded.

Ovipositor and spermatheca: Ratio of dorsal to ventral baculi being 1:1. Spermatheca sclerotised without sclerotised inner structure, strongly curved, bean­shaped widest towards middle and gradually tapering towards apex. Spermathecal gland arising at around 1/3 of spermatheca length from base.

Var ia t io n: Scape and pedicel may be dark brown.

Biology

Z. opacum adults were found under a rotten log, on a leaf at night, in litter, beating broadleaf vegetation and bush, mixed shrub or forest. Plants swept or beaten were blackberry flower and leaves of flax, Apium , Brachyclottis huntii , Coprosma , Muehlenbeckia australis , Myoporum laetum , Plagianthus , Plagianthus regius and Pseudopanax . Others were collected on Melicytus chathamicus branch trap and by Malaise trap at bush edge in grass/ Muehlenbeckia flat. Adults were reared ex: Hebe barkeri , Myrsine bark, Myrsine chathamica bole, Myrsine coxii boles and Plagianthus . Females were collected between 9 Nov. and 6 Mar., and males between 2 Nov. and 2 Mar. Based on labels development of collected immature stages ranges for females from 216– 245 days and for males from 216–316 days. The records do not mention the conditions for rearing.

Distribution

Main Island, Rekohu, and Wharekauri, Pitt Island (Rangiauria) and South East Island (Rangatira) of the Chathams Islands ( Fig. 24 ).

Comments

Hind tarsi, right middle tibia, left antenna segments 9–11 are missing on the lectotype. The locality of the specimen collected by Pascoe from Otago (93–60 BMNH) is questioned by Sharp (1903) in the original species description.

Material examined

Lectotype: designated here. Ψ Chatham Islands, collected by Prof. Schauinsland, labelled type by D. Sharp, Sharp coll. 1905–313 ( BMNH).

Paralectotype: Z. opacum , designated here. Ψ Chatham Islands, Sharp coll. 1905–313. (BMNH).

Other material examined: 67 Ψ, 113 ɗ. Chatham Islands: Chatham Island (1 Ψ BMNH 93–60; 9 ɗ LUNZ m– 270700 –1/8, m– 270700 –4/8; 1 ɗ MONZ; 36 ɗ, 21 Ψ NZAC); Pitt Island (2 Ψ AMNZ 1123, 18847; 2 ɗ, 1 Ψ BMNH 1922–482; 3 ɗ, 6 Ψ LUNZ f– 270700 –2/8, f– 270700 –5/8;10 Ψ, 30 ɗ NZAC); South East Island (8 ɗ, 6 Ψ AMNZ 11223, 11226, 11227, 11229, 11228, 11230, 11231, 11236, 11234, 11237, 11238, 11240, 11241, 11242; 24 ɗ, 20 Ψ NZAC f– 270700 –3/8, f– 270700 –8/8).

Figures

FIGURE 24. Known distribution of: Z. angustifasciatum; Z. batesi; Z. dugdalei; Z. kaikouraiensis; Z. minutum; Z. nonmaculatum; Z. taranakiensis; Z. opacum. The Z. batesi record on Kermadec Island is not shown here. (Map with permission from Ian Henderson, Massey University).

FIGURES 1 – 3. Ventral view of hind femora representing features of: 1, dark coloured femur; 2, light coloured femur with dark ring; 3, light coloured femur without ring.