Cyclorhipidion fukiense (Eggers)

Hoebeke, E. Richard, Rabaglia, Robert J., Knížek, Miloš & Weaver, John S., 2018, First records of Cyclorhipidion fukiense (Eggers) (Coleoptera: Curculionidae: Scolytinae: Xyleborini), an ambrosia beetle native to Asia, in North America, Zootaxa 4394 (2), pp. 243-250 : 244-248

Cyclorhipidion fukiense (Eggers)

( Figs. 1 , 3 , 6 )

Xyleborus fukiensis Eggers, 1941: 225 .

Cyclorhipidion fukiensis: Beaver & Liu, 2010: 24 .

Cyclorhipidion fukiense: Knížek, 2011: 243 .

Xyleborus ganshoensis Murayama, 1952: 16 (Synonymy: Beaver 2011: 284). Xyleborus tenuigraphus Schedl, 1953: 29 (Synonymy: Beaver & Liu 2010: 24).

Diagnosis. Morphometric measurements show consistent diagnostic characters that are reliably and sufficiently distinct to separate C. fukiense from C. bodoanum and C. pelliculosum . Although based on a rather small sample size (6 specimens for C. fukiense and 14 specimens each for C. bodoanum and C. pelliculosum ), the range of body length was reliably different for each species, with no overlap (see Table 1).

Cyclorhipidion fukiense is very similar in general appearance to both C. bodoanum and C. pelliculosum except for body length (compare Fig. 1 ). Cyclorhipidion bodoanum ( Figs. 1 , 2 ) can be easily distinguished by its smaller body length (mean = 2.02 mm; range 1.82–2.16 mm) and its much lighter, yellowish-brown pronotum, sometimes contrasting with the slightly darker elytra. Cyclorhipidion pelliculosum ( Figs. 1 , 4 ) is significantly larger than fukiense (mean = 3.24 mm; range 3.07–3.36 mm), more uniformly darker in coloration, and the declivity is more impressed ( Fig. 7 ) with consistently smaller denticles. Specimens of C. fukiense fall into a size class ( Fig. 1 ) that is intermediate between C. bodoanum and C. pelliculosum . Its mean body length is 2.60 mm with a range of 2.45– 2.76 mm. The pronotum is visibly longer in C. bodoanum with a mean pronotal length/width ratio of 1.20. The pronotum of C. fukiense and C. pelliculosum are less long relative to width, more quadrate, with a mean pronotal length/width ratio of 1.12 ( C. fukiense ) and 1.11 ( C. pelliculosum ).

Redescription. Female: Total length 2.45–2.76 mm, 2.64 times as long as wide (= mean) (see Table 1 for detailed measurements and ratios). Color chestnut brown. Frons reticulate with sparse granules above epistomal margin. Antennal club with sutures and setae near apex, a suture evident near apex on posterior side. Pronotum 1.01–1.10 mm long, 1.12 times as long as wide (= mean), anterior margin rounded, unarmed, disc reticulate, shallowly punctured with abundant short setae. Elytra 1.44–1.51 mm long, 1.48 times as long as wide (= mean); discal striae not impressed, punctures small, about equal in size to interstrial punctures, confused, strial and interstrial punctures with short setae, becoming longer posteriorly. Declivity ( Fig. 6 ) flattened, interstriae 1 slightly raised near middle of declivity, 2 slightly impressed, 3 slightly raised, denticles on 1 and 3 larger than others, strial punctures larger than those on elytral disc and subequal to interstrial punctures, confused, short setae abundant with longer setae along posterior margin.

Male: Unknown.

Figures

FIGURE 1. Comparison of relative lengths of Cyclorhipidion bodoanum, C.fukiense, and C.pelliculosum.

FIGURES 2–4. Cyclorhipidion species, lateral views.2. C. bodoanum. 3. C.fukiense. 4. C. pelliculosum.

FIGURES 5–7. Cyclorhipidion species, oblique views of declivity.5. C. bodoanum. 6. C. fukiense. 7. C.pelliculosum.