Amystax urara Kojima and Yôro, 2020

Kojima, Hiroaki & Yôro, Takeshi, 2020, A new species of Amystax Roelofs, 1873 endemic to the mountainous area of the Yakushima World Natural Heritage site, Kyushu, Japan, Zootaxa 4732 (3), pp. 495-500 : 496

Amystax urara Kojima and Yôro , sp. nov.

http://zoobank.org/ urn:lsid:zoobank.org:act:D4A26A9A-BEC8-495C-9CCC-0854A2978384

( Figs. 1–11 & 13–17 )

Description. Male. Length: 5.8–7.0 mm (including rostrum); width: 2.0– 2.4 mm.

Brownish to blackish brown; antennae and legs reddish to brownish black; scaling variable ( Figs. 1–4 & 6–8 ), dense, scales ovate to circular, grayish brown to ash green with metallic shimmer (or luster); pronotum with stripes; elytra with transverse band behind middle between third intervals, sometimes band indefinite; underside with only hair-like scales.

Head 1.4 times as wide as rostrum; rostrum 1.2 times as long as wide, widest and weakly depressed at base, with faint marginal carina at epistome; postmentum with pair of long setae at middle; eyes moderately convex, exterior contour in dorsal aspect angled about 45º at junction to basal side of rostrum. Pronotum 1.3–1.4 times as wide as head, nearly as wide as long, widest slightly before middle, weakly arcuate at sides; disc wrinkled, without granules or median furrow. Scutellum triangular, bare. Elytra 1.6–1.7 times as long as wide, widest at basal fifth, neither costate across basal margin nor sinuate at side margin; intervals flat, with row of subrecumbent decurved scale-like setae, each slightly longer than one scale on dorsum and becoming longer, inclined on declivity; striae weakly punctate, each puncture filled with lanceolate scale.

Terminalia as illustrated ( Figs. 13–16 ); aedeagal body nearly as long as apodeme, with apical part tapered and attenuate apically; flagellum very long, longer than total length of aedeagus.

Female. Length: 5.7–6.5 mm (including rostrum); width: 2.2–2.3 mm.

Differs from the male by the following points: scaling denser, stripes of pronotum and band of elytra often indefinite; and elytra 1.5–1.6 times as long as wide. Spermatheca ( Fig. 14 ) rather large, about 0.5 mm in length α, ramus and collum not differentiated and very short.

Type material. Holotype male, Nageishidaira (1,700 m a.s.l.), Yakushima Is., Kagoshima Pref., 10.VI.– 12.VIII.2019, H. Kojima . Paratypes: 6 males and 8 females, same data as the holotype (all TUA) .

Distribution. Japan (Kyushu: mountainous area on Yakushima Island).

Etymology. “Urara” means beautiful things in Japanese, and is also the name of our close associate on Yakushima Island, Mrs. Urara Ogata of the Riverside Café Bar, St. Pote. The brownish gray to ash green lustrous scales of this species make it the brightest species in the genus Amystax .

Biology. Adults were found on the leaves of Pieris japonica var. yakushimensis T. Yamaz. and Buxus microphylla var. japonica (Müll. Arg. ex Miq.) Rehder et E.H.Wilson from June to the middle of August. They were not found in October at the type locality. Adults are common in July and their feeding scars were observed on leaf margins of the aforementioned shrubs ( Figs. 9 & 10 ). The microhabitat of this weevil seems to be restricted to shrubs on nearly flat or gently sloping areas at the type locality; no adults were found on shrubs on slopes.

The type locality, Nageishidaira, is a relatively flat, rocky site, ca. 1,700 m a.l.s, with low-growing shrubs such as R. yakushimanum , P. japonica var. yakushimensis , Buxus microphylla var. japonica (Tsuge in Japanese; Buxaceae ), etc. Weevils appeared to associate with, not only P. j. var. yakushimensis , but also B. m. var. japonica .

Remarks. The new species can easily be separated from other congeners, including the recently described Amystax yakushimanus Nakamura and Morimoto, 2015 , by the following key.

1(2) Scales grayish brown to ash green with metallic shimmer. Rostrum with rather shallow transverse depression at base. Pronotum reticulate and without granules on disc. Elytra neither costate nor depressed along basal margin; striae weakly punctate, each puncture with lanceolate scale ( Fig. 11 ). Underside clothed with only hair-like scales.................. A. urara sp. nov.

2(1) Scales grayish, pale ochraceous or brownish, usually without metallic shimmer. Rostrum with more or less distinct transverse depression at base. Pronotum granulate on disc. Elytra costate along basal margin and shallowly depressed along hind margin of costa; striae coarsely punctate, each puncture with broad ovate scale ( Fig. 12 ). Underside densely clothed with ovate scales........................................................................ A. yakushimanus and other congeners

Figures

FIGURES 1–4. Habitus photos of Amystax urara sp. nov. 1. male (Holotype), 2. female (paratype), 3. male (paratype), 4. female (paratype).

FIGURES 5–10. Habitat, habitus and adult host plants of Amystax urara sp. nov. 5. Habitat in Nageishidaira (ca. 1,700 m a.s.l.), 6. adult, female, 7. ditto, male, 8. ditto, female, 9. Pieris, 10. Buxus microphylla var. japonica.

FIGURES 11–12. Pronotum and elytral base of Amystax spp. 11. A. urara sp. nov., 12. A. yakushimanus Nakamura et Morimoto (the arrows a and b indicate a costa along basal margin of elytra and a scale of strial puncture, respectively).

FIGURES 13–17. Aedeagus and spermatheca of Amystax urara sp. nov. 13. Aedeagus, dorsal, 14. ditto, lateral with tegmen. 15. terminal part of flagellum, lateral and enlarged, 16. 9thsternite and spiculum gastrale, 17. spermatheca.