Tomicus yunnanensis Kirkendall & Faccoli

Kirkendall, Lawrence R., Faccoli, Massimo & Ye, Hui, 2008, Description of the Yunnan shoot borer, Tomicus yunnanensis Kirkendall & Faccoli sp. n. (Curculionidae, Scolytinae), an unusually aggressive pine shoot beetle from southern China, with a key to the species of Tomicus, Zootaxa 1819, pp. 25-39 : 32-35

Tomicus yunnanensis Kirkendall & Faccoli , sp. n.

Figs. 2 d, 4a, b, 5, 7

Description

Males and females not readily distinguishable. Total length of specimens of both sexes 4.3–5.4 mm (holotype 5.2; mean = 4.8, N= 20 for means, ranges and ratios), sum of pronotal and elytral (P+E) lengths 4.2–5.4 (mean = 4.9); P+E lengths 2.3–2.6 times wider than elytra (mean = 2.4). Mature color dark reddish brown. Frons shining, weakly to moderately impressed, upper margin more strongly so; a fine median carina from middle of frons to just above epistoma. Lower frons bordered laterally by narrow carinae from epistoma to level of middle of eye. Surface smooth centrally, outer fourths with fine vertical crenulations, with scattered deep setiferous punctures. Antennal funicle with 6 segments; club and funicle uniformly brown; club ovate, narrowly rounded, tip with abundant vestiture of short pale hair-like setae, suture of first segment with a row of fairly uniformly short setae ( Figs. 4 a, b). Pronotum in mature individuals very dark reddish brown (almost black), stout, 0.8x longer than wide, strongly constricted in anterior third. Dorsal surface shining, finely, fairly densely punctured ( Fig. 7 ). Vestiture of moderately abundant, fine, pale setae, denser along lateral areas of pronotum. Legs almost black, same color as rest of body and pronotum. Protibia usually with six (five to seven) marginal teeth (15/20 with 6), the first (tooth closest to body) often separated from the remaining teeth ( Fig. 5 ). Colour of elytra dark reddish brown in mature specimens, paler than pronotum and body, basal 1/6th to 1/5th darker. Elytra 1.6–1.8x longer than wide (mean and holotype = 1.7), 2.3–2.5x longer than pronotum (mean = 2.4). Sides subparallel, broadly rounded in posterior fourth. Disc shining, with weak traverse crenulations, these most dense and most pronounced basally. Striae with punctures spaced by approximately their diameter. Interstriae approximately 3– 4 x wider than striae, with uniseriate rows of widely spaced granules, these more closely spaced on declivity than on disc, generally spaced by about 3–5 punctures of adjacent striae. Interstriae with erect hair-like setae, scattered on disc but denser on declivity, about as long as distance between striae. Declivity ( Fig. 2 d, see also Fig. 7 ) broadly rounded, beginning at distal fourth of elytra; interstriae similarly sculptured, all but interstria 2 with a row of small conical setiferous tubercles. Interstria 2 strongly impressed but broadly convex to flat, punctures evenly spaced, irregularly uniseriate (appearing to zig-zag down declivity). Punctures of striae 1 to 3 less than or equal to twice as large as interstrial punctures. Interstriae 1 and 3 weakly elevated. Granules on interstriae 1 and 3 near base of declivity closely spaced, distance between pairs of granules = 1/2 distance separating rows of granules of interstria 1 from those of interstria 3. T. yunnanensis can also be identified by comparing DNA sequences to those in GenBank, for nuclear genes ITS-2 and 28S (sequences AY570812 - AY570813 , AY570826 - AY570827 , respectively) or mitochondrial gene COI (sequences AY570844 - AY570892 ) ( Duan et al., 2004).

Type material

All from Yunnan Province in China. Holotype (slightly immature; sex not determined) and 1 paratype, Xiundian, 22 April 2003; 4 paratypes, Zhanyi, 22 April 2003; 1 paratype, Zhanyi, 6 May 2004; 5 paratypes, Shilin (Shilin Stone Forest), 2 April 2003; 7 paratypes, Gejiu, 2 April 2003; 4 paratypes, Midu, 12 April 2003; 3 paratypes, Xiangyun, 11 April 2003; 6 paratypes, Shizong, 23 April 2003; 2 paratypes, Lufeng, 6 May 2004; 2 paratypes, Shilin, Chonghu, N 24o 43.3’ E 103o 24.5’, L. R. Kirkendall,Ye Hui & Chen Peng, from Tomicus - killed P. yunnanensis . The holotype is deposited in the Natural History Museum, London. Paratypes will be distributed to the collections of the Chinese Academy of Sciences (Beijing), Kunming University (Yunnan), National Museum of Natural History (Washington, D. C., USA), The Natural History Museum (London, England), Naturhistorisches Museum Wien (Vienna, Austria), Milos Knizek (Prague, Czech Republic), Mikael Mandelshtam (Moscow, Russia) and the collections of LRK and MF.

Etymology

The Latin epithet for the new species was chosen to reflect to the Chinese province where research on the new species has focussed (Yunnan) as well as the only host tree known, Yunnan pine. We suggest “Yunnan shoot borer” be used as a common name.

Differential diagnosis for Tomicus species in southern China

Foresters have assumed that the Tomicus species making longitudinal galleries in P. yunnanensis was T. piniperda . In fact, the latter species has not yet been collected from Yunnan; the Tomicus samples sequenced by Duan et al. (2004) and those identified in this study include only T. yunnanensis , T. minor and T. brevipilosus . In southwestern China and northern Burma, T. minor can easily be distinguished from the other species by the presence of setiferous (hair-bearing) granules on interstria 2 on the declivity, which are absent in the other two species. Most Yunnan Tomicus specimens we have seen are T. yunnanensis ( Table 1 ). If a specimen is encountered that seems to differ (and is not T. minor ), the equal elytral setae characteristic of T. brevipilosus are best be viewed from the side: in T. brevipilosus the erect interstrial setae do not noticeably increase in length from the elytra to the declivity, as they do in T. yunnanensis . The declivities of T. brevipilosus and T. yunnanensis also differ in many details (see key and Fig. 2 ); for example, when material of both species is available, interstria 2 of T. brevipilosus appears distinctly narrower and less impressed on the declivity and the punctures of the adjacent striae 1 and 3 are more clearly impressed.

Figures

FIGURE 2. Eytral declivity of Tomicus species: (a) brevipilosus (Eggers), (b) T. piniperda (Linnaeus), (c) T. destruens (Wollaston), (d) T. yunnanensis sp. n. (holotype).

FIGURE 4. Antenna of Tomicus species: (a, b) T. yunnanensis, (c) T. piniperda (Linnaeus), (d) T. destruens (Wollaston).

FIGURE 5. Protibiae of Tomicus species: T. destruens (Wollaston) (left), T. yunnanensis sp. n. (right).

FIGURE 7. Tomicus yunnanensis sp. n., dorsal and lateral habitus of holotype.