Isometopini Fieber 1860

Tribe Isometopini Fieber, 1860

Isometopus Fieber, 1860

Isometopus bipunctatus Lin, 2004 [= Isometopus yehi Lin, 2004 syn. nov.] (Figs 1E–F, 2A–B, 3A–B)—Taiwan (Nantou, Pingtung)— Fraxinus griffithii (bark). Note: The collection records of both I. bipunctatus and I. yehi indicate that these two are sympatric and conspecific (the former species was named for females of the latter).

Our recent investigation in Kenting, Pingtung County showed that the adults of both sexes and late instar immatures (Figs 1A, E–F) inhabiting together on the trunk or under the characteristic loose flakes of ash tree, Fraxinus griffithii; the first author observed that the fuscous male (Fig. 1E) attempted to mount the spotted female (Fig. 1F) in an aspirator. Such conspicuous sexual dimorphism in adult was also reported for I. takaii Yasunaga (Figs. 1G, 3C–D) which is also associated with Fraxinus griffithii on Ishigaki Island (Yasunaga, 2005) and assumed to be closely related to I. bipunctatus. The male final (5th) instar nymph of I. bipunctatus (Fig. 2B) is at first sight like the female (Fig. 2A), but they can be easily separable from each other by different size of the compound eyes; the male vertex is almost equal in width to a compound eye, whereas in female the vertex is more than 1.5 times as wide as the eye.

Isometopus hasegawai Miyamoto, 1965 —Taiwan (Hualien, Nantou), Ryukyus (Yaeyama Group)—Unknown; in Ryukyus, known to inhabit Pinus luchuensis Mayr (Pinaceae) (Yasunaga, 2005).

Isometopus ishigaki Yasunaga, 2012 [original description by Yasunaga (2005), see also Yasunaga et al. (2012)]— Ryukyus (Yaeyama Group)—On bark and under loose flakes of Fraxinus griffithii; two adults were collected from cinnamon, Cinnamomum tenuifolium (Makino) Sugim. ex H. Hara (Lauraceae) (Yasunaga & Hayashi, 2002).

Isometopus lini Lin, 2004 —Taiwan (Taichung)—Unknown. Note: Based on the general appearance, a female recorded from Taiwan as I. nigrosignatus Ren (Lin & Yang 2004) may represent this species; the identity of I. lini requires further verification.

I. nigrosignatus Ren, 1987 — Taiwan (Nantou), China (Yunnan)—Unknown.

Isometopus renae Lin, 2004 — Taiwan (Nantou)—Unknown.

Isometopus takaii Yasunaga, 2012 [original description by Yasunaga (2005), see also Yasunaga et al. (2012)] (Figs 1G, 3C–D, 9)—Ryukyus (Ishigaki Island)—On bark and under loose flakes of Fraxinus griffithii.