Morphological Variability and Taxonomy of Coraebus Hastanus Gory & Laporte De Castelnau, 1839 (Coleoptera: Buprestidae: Agrilinae: Coraebini: Coraebina)

Zootaxa 3682 (1): 178–190 ISSN 1175-5326 (print edition) www.mapress.com/zootaxa/ Article ZOOTAXA Copyright © 2013 Magnolia Press ISSN 1175-5334 (online edition) http://dx.doi.org/10.11646/zootaxa.3682.1.9 http://zoobank.org/urn:lsid:zoobank.org:pub:F6F98526-64C3-4D68-8852-8F6DD9407A1B Morphological variability and taxonomy of Coraebus hastanus Gory & Laporte de Castelnau, 1839 (Coleoptera: Buprestidae: Agrilinae: Coraebini: Coraebina)

HONGXIA XU1, 2, VÍTĚZSLAV KUBÁŇ3, MARK G. VOLKOVITSH4, SIQIN GE1, MING BAI1 & XINGKE YANG1,5 1Institute of Zoology, Chinese Academy of Sciences, Beijing, China 2University of Chinese Academy of Sciences, Beijing, China 3National Museum (Natural History), Prague, Czech Republic 4Zoological Institute, Russian Academy of Sciences, St. Petersburg, Russia 5Corresponding author. Xingke Yang, Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Beijing 100101, China. E-mail: [email protected]

Abstract

Coraebus hastanus Gory & Laporte de Castelnau, 1839 is easily distinguished from the other species of the genus Corae- bus Gory & Laporte de Castelnau, 1839. It was divided into three subspecies, but the main diagnostic characters were variable. In order to understand the morphological variability and taxonomy of subspecies of C. hastanus, shape of elytral apex, lateral margin of elytra and the aedeagi were analyzed using geometric morphometric and traditional morphometric approaches. Based on the results and distribution patterns of the three subspecies, C. hastanus oberthueri Lewis, 1896 is treated as synonym of C. hastanus Gory & Laporte de Castelnau, 1839, and C. hastanus ephippiatus Théry, 1938 is elevated to species rank, and these two species are also redescribed and illustrated.

Key words: Coleoptera, Buprestidae, Agrilinae, Coraebini, Coraebina, Coraebus hastanus, Coraebus oberthueri, Corae- bus ephippiatus, taxonomy, morphological variability, Oriental region

Introduction

Morphological variability is very common in the species of the genus of Coraebus Gory & Laporte de Castelnau, 1839. Many morphological characters were used to distinguish species of Coraebus, the body shape, shape of the elytral apex, coloration and the shape of ornamentation of the dorsal surface (Kubáň, 1996), these characters are usually relatively invariable, but in some closely related species they exhibit a high degree of variability (Kubáň, 1995), which makes it difficult to use them for species differentiation. Coraebus hastanus Gory & Laporte de Castelnau, 1839 is distinctly different from the other species of the genus of Coraebus and it can be easily recognized by the body shape and ornamentation (Descarpentries & Villiers, 1967). Théry (1938) divided C. hastanus into three subspecies: Coraebus hastanus hastanus Gory & Laporte de Castelnau, 1839, C. hastanus oberthueri Lewis, 1896 and C. hastanus ephippiatus Théry, 1938, based on the shape of the elytral apex and lateral margins of elytra. Kurosawa (1953) carefully examined many specimens from the Ryukyu Islands and Taiwan, noticing that among specimens from various of the Ryukyu Islands, only one specimen was closely similar in the shape of elytral apex to C. hastanus oberthueri, other specimens, differed from C. hastanus hastanus in having denticles on the sutural side of inner spine and external side of outer spines. He believed that they were morphological variability of C. hastanus oberthueri. Subsequently, the taxonomic ranks of the three subspecies of C. hastanus were generally accepted by buprestid research community. However, if C. hastanus is indeed represented by three distinct subspecies based on the shape of the elytral apex and lateral margins, the questions of how to identify the subspecies correctly and how to understand their morphological variability remained. Shape analysis is one approach to understanding morphological variability. Traditionally, morphometric data

178 Accepted by Brian Levey: 10 May 2013; published: 26 Jun. 2013 have been measurements of length and width. Such a data set contains relatively little information about shape, and some of this information is fairly ambiguous (Zelditch et al, 2004). Geometric morphometric analyze the shape and morphological structure based on landmarks. With this method, the morphology of an object is represented by the coordinates of a set of landmark points (Bookstein, 1991). It has a tremendous advantage in offering precise and accurate description, allowing us to visualize differences among complex shapes (Fontoura & Morais, 2011). In order to evaluate the morphological variabolity and understand the taxonomy of three subspecies of C. hastanus, we examined the specimens deposited in a number of museums. Morphological variability of aedeagi, apex and lateral margins of elytra were compared by the geometric morphometric approach. Also, the shape of the elytra was compared by the traditional morphometric approach. Based on the results of the morphometric approaches and distributions, C. hastanus oberthueri is treated as a synonym of C. hastanus; and C. hastanus ephippiatus is elevated to species level. Many species of Coraebus and various Coraebini Bedel, 1921 show high morphological variability that makes many traditionally used characters unreliable, we hope that the morphometric approaches used here can provide new ways for analyzing this morphological variability.

Material and methods

Abbreviations of the collections

BMNH The Natural History Museum (British Museum of Natural History), London, Great Britain HBUM Museum of Hebei Univerity, Baoding, Hebei, China IZAS Institute of Zoology, Chinese Academy of Sciences, Beijing, China JSNC Jiangxi Forest Pest and Disease Control Station, Nanchang, Jiangxi, China MNHN Museum national d’Histoire Naturelle, Paris, France NMPC National Museum (Natural History), Prague, Czech Republic USNM United States National Museum of Natural History, Smithsonian Institution, Washington, D.C., U.S.A. VKCB V. Kubáň collection, Brno, Czech Republic ZIN Zoological Institute, Russian Academy of Sciences, St. Petersburg, Russia

Dissection and imaging. Entire abdomens were separated from the body and kept in distilled water at room temperature for more than 12 hours. The aedeagi or ovipositors were separated from abdominal segments and mounted in a cavity slide under distilled water for observation, photographed in glycerol, then rinsed in water, mounted on a paper card in euparal which was pinned below the specimens. All images were taken using a Nikon D300s digital camera fitted to Zeiss Discovery V12 stereoscopic dissecting microscope. Morphometrics. Landmarks and curves were selected based on homologous or corresponding criteria. Among these, 4 landmarks and 1 curve (30 semi landmarks) designed for elytral apex (Fig. 2A), 3 landmarks and 3 curves (50 semi landmarks) for aedeagi (Fig. 4A) and 2 landmarks, 1 curve (42 semi landmarks) for lateral margin of elytra (Fig. 5A). The images of adeagus (17 specimens), elytral apex (48 specimens) and lateral margin (49 specimens) were entered in tps-UTILS 1.38 (Rohlf, 2006a) and Cartesian coordinates of landmarks were digitized with tps-DIG 2.05 (Rohlf, 2006b). Landmark configurations were scaled, translated and rotated against the consensus configuration using the GLS (Generalized least squares) Procrustes superimposition method (Bookstein, 1991). The coordinates were analyzed using tps-RELW 1.44 (Rohlf, 2006c) to calculate eigenvalues for each principal warp (Bai et al, 2010, 2011, 2012). The parameters of length, width etc of elytra (Fig. 1) from 51 specimens were used to compare morphological variability of elytra; ratio of the different parameters were also calculated except for the elytral length, all the data were obtained from the images taken by the same camera and analyzed by Microsoft Excel (2003) and SPSS (17.0) (Dytham, 2011). Significant difference was analyzed through one way ANOVA and multiple comparisons were conducted by LSD (Least Significant Difference). Measurements. Diagrammatic sketch as in Fig. 1; el—elytra length—from humeri to apex of elytral suture; sl—suture length—from the apex of scutellum to the apex of elytral suture; wa—width of elytral apex—width

MORPHOLOGICAL VARIABILITY OF CORAEBUS HASTANUS Zootaxa 3682 (1) © 2013 Magnolia Press · 179 across the bottom of the apical emargination; wb—width of elytral base—elytral width across the apex of scutellum; wm—maximal width of elytra—width across the widest parts of elytra.

FIGURE 1. The Diagrammatic sketch of elytral measurements.

Results

1. The shape of elytral apex

Théry (1938) illustrated the elytral apex of the three subspecies of C. hastanus which were diagnosed mainly by the shape of apex and lateral margin of elytra, however the shape of the elytral apex varies highly. This character varies not only among the different subspecies, but also within same subspecies (Fig. 2). Coraebus hastanus hastanus: elytral apex relatively uniform, no denticles on external side of the outer spine and sutural side of inner spine (Figs. 2A–C); C. hastanus oberthueri: external side of outer spine and sutural side of inner spine with denticles, number of denticles from 1-2 denticles (Fig. 2F) to regular dentation (Figs. 2D–E), sometimes sutural side slightly extended to the outside, even reaching middle of the apex (Fig. 2D, type specimen of C. hastanus oberthueri). We even found a single specimen, having a different shape of elytral apex on each elytron (a specimen from Japan, Okinawa), right elytron similar to elytra of C. hastanus hastanus (Fig. 2C), but left elytron with denticles on the external side of outer spine and sutural side of inner spine (Fig. 2F, flip horizontal) like that in C. hastanus oberthueri. Coraebus hastanus ephippiatus: except that the elytral apex is more shallowly emarginated and the spines shorter, external side of the outer spine and sutural side of inner spine vary from smooth (Fig. 2G) to regularly toothed, and the sutural side in some specimens extends to the outside, is similar to the type specimen of C. hastanus oberthueri (Fig. 2I).

2. Geometric morphometrics

2.1. Morphological variability of the elytral apex (Fig. 3)

The first two relative warps of the left and right elytron respectively account for 67.97%, 64.38% of the variability among the species. These warps were computed by a singular-value decomposition of the weight matrix. The first two relative warps were plotted to indicate variation along the two axes. The shape changes among different species implied by variation along the first two relative warp axes and shape changes are shown as deformations of the GLS (Generalized least squares) reference, using thin-plate splines. The splines, which show the deformation of the elytral apex in comparison to that of the reference, indicate the most significant deformation, as it is situated furthest from the origin (Bai et al, 2012). The position of points which corresponded to each specimen was distinctly different between left elytron and right elytron, two elytra of the same specimen were not similar to each other. The specimens of three subspecies were marked in a different color. The points were very diffuse and showed no distinct border. On the left elytron (Fig. 3A), most points for C. hastanus ephippiatus (yellow points) were scattered above the horizontal axis, the most points for C. hastanus hastanus (blue points) were scattered below the horizontal axis. On the right elytron (Fig. 3B), they were inverted. The points for C. hastanus oberthueri (red points) were scattered between them. The results showed that the morphological characters of elytral apex are variable; the three subspecies cannot be distinguished by the shape of elytral apex only.

MORPHOLOGICAL VARIABILITY OF CORAEBUS HASTANUS Zootaxa 3682 (1) © 2013 Magnolia Press · 181 FIGURE 3. The relative warps (A, B) and consensus configurations of elytral apex (C, D). A and C, left elytron; B and D, right elytron; Coraebus hastanus hastanus; C. hastanus ephippiatus; C. hastanus oberthueri.

FIGURE 4. Morphological variability of aedeagus. A, the aedeagus of Coraebus hastanus ephippiatus; B, the relative warps and consensus configuration; and 1, C. hastanus ephippiatus; and 2, C. hastanus hastanus; and 3, C. hastanus oberthueri.

FIGURE 5. Morphological variability of the lateral margin of elytra. A, land marks, specimen from Laos; B, relative warps; C, consensus configuration. and 1, Coraebus hastanus ephippiatus; and 2, C. hastanus hastanus; and 3, C. hastanus oberthueri.

The first two relative warps account for 74.00% of the variability among the species. The points corresponding to aedeagus shape were very diffused. Five points which present the genital variation of C. hastanus ephippiatus (yellow points) are from the specimens originating from four different areas in China. They are concentrated in right bottom corner, and distinctly separated from the other subspecies. But the points corresponding to C. hastanus hastanus (blue points) and C. hastanus oberthueri (red points) which originated from Vietnam, China, Japan and from the Philippines are very diffuse and there is no clear border between the two groups.

2.3. Morphological variability of lateral margin of elytra (Fig. 5)

The first two relative warps account for 73.18% of the variability among the species. The distributional data for the lateral margin of elytra were not consistent with the data for aedeagus and the elytral apex. C. hastanus ephippiatus (yellow points) was relatively well separated from the other subspecies in spite of the fact that they are very diffuse, however there is no distinct border as there was for the aedeagus. Points for C. hastanus hastanus and C. hastanus oberthueri are also mixed with each other.

3. Traditional morphometrics (Fig. 6)

The length of suture and shape of the elytral apex of the three subspecies were significantly different (sl: F=

4.9869, F0.05=3.2256, wa: F=11.4695, F0.05=3.1996). The results showed that in C. hastanus ephippiatus, the elytra is shorter and the apex is narrower than in other subspecies. The elytral lateral margin of C. hastanus ephippiatus was arcuate, ratio of wm/wa also reach significant level (F=9.7147, F0.05=3.1996).

The elytral length, width of base and ratio sl/wm were also significantly different (el: F=4.9846, F0.05=3.1951; wb: F=3.2354, F0.05=3.1996, sl/wm: F=4.9869 F0.05=3.2257) among the three subspecies. But we could not observe a consistent tendency. The wm/wb is almost equal 1 and the difference of among the subspecies does not reach significant level (F=1.8388, F0.05= 3.1950). All the parameters do not reach a significant level between C. hastanus hastanus and C. hastanus oberthueri, their shape of elytra was relatively similar in both subspecies.

FIGURE 6. Comparison of the different parameters and ratios of elytra. A, parameters of elytra; B, ratios of elytra. Columns with same letters (a) are not significantly different.

4. Distribution of three subspecies (Fig. 7)

The distributional data comprise the label information from the studied specimens and the distributional data provided Kubáň et al (2006) and Bellamy (2008). There were no clear border between distributional ranges of C.

MORPHOLOGICAL VARIABILITY OF CORAEBUS HASTANUS Zootaxa 3682 (1) © 2013 Magnolia Press · 183 hastanus hatasnus and C. hastanus oberthueri, which are widely distributed in southeastern Asia, from Ceram Island (Indonesia), extending westward and northward to Nepal, China and Japan. These subspecies had four overlapped areas in Philippines, Thailand and India, respectively. C. hastanus ephippiatus was restricted to south China. Distributional ranges of C. hastanus hastanus and C. hastanus ephippiatus overlapped in Guizhou, China.

FIGURE 7. Distribution map of three subspecies. , C. hastanus hastanus; , C. hastanus oberthueri; , C. hastanus ephippiatus.

Conclusions

The results showed that C. hastanus is a polymorphic species or species group though the analysis of morphological variability did not confirm the division of this species into three subspecies. As demonstrated above, it is impossible to diagnose C. hastanus hastanus and C. hastanus oberthueri based only on shape of the elytral apex, since this shape varies within a single specimen (right elytron is similar to C. hastanus hastanus, but left elytron similar to C. hastanus oberthueri). The analysis of other morphological characters by geometric and traditional morphometric approaches, has shown that there is no significant difference between these subspecies. Analysis of the distribution patterns also showed that there is no clear allopatry between the two subspecies. Based on the results obtained, C. oberthueri is treated as a synonym of C. hastanus. Based on the analysis of morphological variability of the aedeagus by the geometric morphometric approach, C. hastanus ephippiatus can be separated from the other subspecies. This separaration was also supported by the results of geometric morphometric analysis of morphological variability of lateral margin of elytra and by comparison of the different parameters and ratios of elytra based on traditional morphometric approach. The geographical distribution patterns also support the idea that C. hastanus ephippiatus is separated from the other subspecies. Therefore, we have elevated C. hastanus ephippiatus to species level.

184 · Zootaxa 3682 (1) © 2013 Magnolia Press XU ET AL. FIGURE 8. Habitus, aedeagi and ovipositors. Coraebus ephippiatus. A: dorsal habitus of the syntype specimen; B: aedeagus; C: ovipositor; C. hastanus. D: dorsal habitus of specimen from Thailand; E: dorsal habitus of the specimen from Vietnam; F, G: aedeagus H: ovipositor.

Key to the species

1. Elytral apex narrow, shallowly emargined, lateral margin arched towards posterior 1/3 of elyron (Figs. 2G–I). Parameres of aedeagus dilated medially (Figs. 4A, 8B) ...... Coraebus ephippiatus Théry, 1938 - Elytral apex deeply emargined, lateral margin relatively straight towards posterior 1/3 of elytron (Figs. 2A–F ). Parameres of aedeagus subparallel (Figs. 8F–G) ...... Coraebus hastanus Gory & Laporte de Castelnau, 1839

Coraebus ephippiatus Théry, 1938, stat. nov. (Figs. 2G–I, 4A, 8A–C)

Coraebus hastanus ephippiatus Théry, 1938: 176. Type locality: China (without exact data).—Kurosawa, 1953: 108, 109; Kubáň, 2006: 410; Bellamy, 2008: 1812.

Description (based on syntype, MNHN). Elongate, body length 10.2 mm, width across the posterior 1/3 of elytra 3.2 mm; vertex blue with green tinge, gradually becoming green toward supra-antennal groove; frons with black triangular depression, covered with white pubescence; frons below supra-antennal grooves and clypeus black; pronotum blue, with green tinge; scutellum green with blue tinge; base and apex of elytra green, medial part with black triangular patch, white pubescence in the shape of a triangle at posterior 1/3 of elytra; ventral side, antennae and legs black. Head. Vertex slightly projecting beyond anterior margin of eyes; with distinct longitudinal median line; eyes oval, large; frons broadly depressed medially; supra-antennal groove narrow, deep; carina above supra-antennal groove interrupted medially; frontoclypeal keel straight; anterior margin of clypeus straight, shorter than diameter of antennal socket; sculpture of vertex and upper part of frons consisting of coarse punctures and distinct transverse wrinkles, punctures usually well separated. Antennae short, extending only to midlength of pronotum, sharply serrate from antennomere 4; antennomere 1 suboval, shorter than 2; antennomeres 2 and 3 conically truncated with rounded edges; antennomere 3 short, 0.5 times as long as antennomere 2; antennomeres 4–11 subequal. Pronotum. 1.6 times as wide as long, convex, widest across basal 1/3, subconically tapering anteriorly, with distinct basal impression; anterior margin feebly arcuate; lateral margins relatively straight; posterior angles almost rectangular, posterior margin lobate, with medial part broadly extended in front of scutellum; sculpture consisting of coarse, fused punctures, gradually sparser towards sides and base. Scutellum. 1.4 times as wide as long, subpentagonal; its margins elevated, keel-like, lustrous. Elytra. nearly 2.2 times as long as wide, at base almost as wide as pronotal base, humeri prominent; disc deeply depressed between humeri and scutellum; lateral margins converging posteriad to midlength then diverging to posterior 1/3, and distinctly converging to apex; elytral apex shallowly emargined, sides of emargination with small spines; elytral epipleura widest just below humeri, gradually narrowing towards external margin of metacoxa, then sharply narrowing and extending to posterior 1/3 of elytral length; sculpture consisting of dense, coarse punctures and regularly transverse wrinkles. Ventral side. Mentonniere very narrow, separated by groove; prosternal process subparallel between coxae, apex round, lateral margins elevated, keel-like; sculpture consisting of coarse, large punctures and irregular wrinkles; ventral surface covered with long white, sparse pubescence; abdominal ventrite 1 longer than 2, suture well indicated; ventrites 3 and 4 subequal; ventrite 5 shorter than 3 + 4; ventral side covered with punctures and sparse white pubescence. Aedeagus as in Figs. 4A, 8B; ovipositor as in Figs. 8C. Type material examined. Syntype, sex unknown (MNHN): “Ephippiatus Laf[erté] Chine \ hastanus ssp. ephippium [sic!] Théry [handwritten] Type [red print] \ Coraebus hastanus ssp. ephippiatus Th. [handwritten] [printed, crossed handwriten] \ COLLECTION de BONNEUIL [printed] \ MUSEUM PARIS 1935 Coll A. THÉRY. [yellow label, printed] / SYNTYPE [red label, printed] / MNHN EC3492 [printed]” Additional material examined. CHINA: HENAN prov.: Xinxian, Yongshan, 18.vii.1999, Shi leg. (1 ♀, IZAS). HUBEI prov.: Tongshan (20 km NW), 7.–17.vi.2004, J. Turna leg. (1 ♂, VKCB). HUNAN prov.: Mangshan mts., Chengzhou, Jianhua, 8.vi.2004, Zhao leg. (2 ♂, 2 ♀, HBUM); Zhuzhou, Jinxi, 14.vi.2000, Liang

186 · Zootaxa 3682 (1) © 2013 Magnolia Press XU ET AL. leg. (2 ♀, HBUM); Tianpingshan mts., 1500 m, 8.viii.1998, Hong Liu leg. (1 ♀, IZAS). JIANGXI prov.: Jian, Anfu, Wugongshan mts., 7.viii.2008, Ze, Meng leg. (1 ♂, JSNC); Wuyuan (1 ♀, JSNC). TAIWAN: Bukai, 11.vi.1954 (1 ♀, USNM). ZHEJIANG prov.: [“Chekiang”] 17.vi.1919, E. Suenson leg. (2 ♀, USNM); Zhoushan [“Chusan”], 10.vii.1931, C. Piuvot leg. (1 ♂, 2 ♀, IZAS); same data but: 7.viii.1931 (1 ♂, 1 ♀, IZAS). Variability. Sides of emargination on elytral apex with one or two short spines or regular denticles, variability as in Figs. 2G–I. Colour relatively stable, base of pronotum and elytra always blue or green. Distribution. China (Fujian, Guangxi, Guizhou, Henan, Hubei, Hunan, Jiangxi, Shanghai, Taiwan, Yunnan, Zhejiang). Remarks. The original description of Coraebus hastanus ephippiatus consisted only of the illustration showing the shape of the apex of elytra without any description and detailed label information. We only know that the type originated from China. According to the general distributions of the species, it is presumed that the type specimen came from South-East of China (Fig. 7).

Coraebus hastanus Gory & Laporte de Castelnau, 1839 (Figs. 2A–F, 8D–H)

Coraebus hastanus Gory & Laporte de Castelnau, 1839: 10. Type locality: Northeastern India, West Bengal province [“Bengal”].—Kurosawa, 1953: 108; Kubáň, 2006: 410; Bellamy, 2008: 1812. Coraebus bajulus Deyrolle, 1864: 122. Type locality: Indonesia, Ceram Island. Synonymy by Théry, 1926: 257.—Kurosawa, 1953: 108 (synonym of hastanus); Kubáň, 2006: 410 (synonym of hastanus); Bellamy, 2008: 1812 (synonym of hastanus). Coraebus oberthüri Lewis, 1896: 335, syn. nov. Type locality: Japan, Ryukyu Islands, O-shima Island. Coraebus hastanus oberthueri: Théry, 1938: 176 (as oberthuri [sic!]): Kurosawa, 1953: 108, 109 (as oberthüri [sic!]); Kubáň, 2006: 410; Bellamy, 2008: 1812 (as oberthuri [sic!]).

Description (based on studied specimens). Elongate, slightly convex dorsally, flattened ventrally, body length 10.5 mm, width across the posterior 1/3 of elytra 3.6 mm; vertex green; frons above supra-antennal groove green with copper tinge; frons below supra-antennal grooves and clypeus black; pronotum green with blue tinge, near posterior angles green with golden tinge; base and apex of elytra green with golden tinge, medial part of elytra with large triangular patch, which is black, with blue or golden tinge; white pubescence forming a small triangular shape at bottom of patch; ventral side, antenna and legs black. Head. Vertex slightly projecting beyond anterior margins of eyes, with distinct longitudinal median line; eyes oval, large, inner margins weakly arcuate, supra-antennal grooves narrow, deep, closed near eyes; carina above supra-antennal grooves interrupted medially; frontoclypeal keel straight; anterior margin of clypeus straight, shorter than the diameter of antennal socket; sculpture of vertex and upper part of frons consisting of coarse punctures and distinct transverse wrinkles, the punctures usually well-separated. Antennae shorter than pronotum, sharply serrate from antennomere 4; antennomere 1 subovate, shorter than 2; antennomeres 2 and 3 conically truncated, with rounded edges; antennomere 3 0.5 times as long as antennomere 2; antennomeres 4–11 nearly subequal. Pronotum. 1.7 times as wide as long, convex; widest across basal 1/3, subconically narrowing anteriorly, slightly narrowing posteriorly, with distinct basal impression; anterior margin slightly projecting medially, lateral margins relatively straight, posterior angles obtuse, posterior margin lobate, broadly extended in front of scutellum; sculpture consisting of coarse punctures and wrinkles; punctures generally fused transversely forming sinuous wrinkles. Scutellum. 1.4 times as wide as long, subpentagonal; margins elevated, keel-like, sculpture consisting of fine punctures. Elytra. nearly 2.2 times as long as wide, at base almost as wide as pronotal base, humeri prominent, disc deeply depressed between humeri and scutellum; apex of elytra deeply emarginate, each side with long spine; outer spine sharp, long, sutural spine smaller (Figs. 2D–F); sculpture consisting of dense, coarse punctures and regularly transverse wrinkles. Ventral side. Prosternal process subparallel between coxae, apex round, lateral margins elevated, keel-like; sculpture consisting of coarse, large punctures and irregular wrinkles, ventral side covered with long white, sparse

MORPHOLOGICAL VARIABILITY OF CORAEBUS HASTANUS Zootaxa 3682 (1) © 2013 Magnolia Press · 187 pubescence; abdominal ventrite 1 longer than 2, ventrites 3 and 4 subequal, ventrite 5 shorter than 3 + 4, its posterior margin emargined. Aedeagus and ovipositor as in Figs. 8F–H. Type material examined. Coraebus oberthueri Lewis, 1896: Syntype ♂ (BMNH): “O Shima (Ferriè J [leg.]) [handwritten] / Japan G. Lewis 1910-320 [printed] / Type H.T. [printed, round label with red circle] / Coroebus oberthuri Lewis Type [handwritten].” Note. According to Bellamy (2008) the types of Coraebus hastanus and C. bajulus are deposited in MNHN, but we could not find them in the MNHN collection. It is quite possible that the types of both species are among 4 specimens labelled “bajulus (Dej.)” in the Oberthür collection which includes the specimens from Dejean, Laporte de Castelnau, Gory and Deyrolle collections (V. Kubáň’s observation). Information on the labels of these specimens is as follows: (1) “type Deyr.”; (2) “Ceram”; (3) no label; (4) “Shanghai”. Additional material examined. Central BURMA: Karen Hills (“Carin Cheba”) NE of Toungoo, 900–1100 m, 5.viii.1898, L. Fea leg. (3 specimens, ZIN). CHINA: GUIZHOU prov.: Fanjingshan mts., 350 m, vii.1998, Hong Liu leg. (1 ♂, IZAS). YUNNAN prov.: Cangyuan, 1130 m, 16.–18.vii.2008, Jishan Xu & Zhenhua Zhou leg. (1 ♀, HBUM). INDIA: Assam, Chabua, vii.1943, D.E. Hardy leg. (1 ♀, USNM). JAPAN: RYUKYU Islands: O-shima Island, Amami (“Nase”), 9.vii.1932, L. Gressit leg. (1 ♂, USNM); Okinawa Island, vi.1978, W.D. Field leg. (1 ♀, USNM). LAOS: Paklay, 15.viii.1917, C.F. Baker leg. (1 ♂, 1 ♀, USNM). PHILIPPINES: LUZON: Los Baños, C.F. Baker leg. (1 ♀, USNM); Tayabas, C.F. Baker leg (2 ♂, 1 ♀, USNM). MINDANAO: C.F. Baker leg. (1 ♂, USNM). NEGROS, v.1991, C.V. Piper leg. (1 ♂, 1 ♀, USNM); Cuernos mts., C.F. Baker leg (2♂, 2♀, USNM). PALAWAN: Tanabag river, 150 m, xii.1991, Bolm leg. (1 ♂, VKCB); same data but: 2.–5.i.2007 (1 ♂, 1 ♀, NMPC). POLILLO: C.F. Baker leg. (1 ♂, USNM). SAMAR, C.F. Baker leg. (1 ♂, 1 ♀, USNM). THAILAND: MAE HONG SON prov.: PAI, 6.–9.vi.1997, M. Snížek leg. (1 ♀, VKCB). VIETNAM: Hanoi (2 ♂, 2 ♀, IZAS); GIA-LAI prov., Tainguen, Buon-loi (20km N), 1.–14.xii.1988, A. Gorohov leg. (2 specimens, ZIN). Variability. Specimens from Laos are distinctly larger, base of pronotum and elytra red with copper tinge (Fig. 5A); specimens from Vietnam are blue (Fig. 8E); external side of outer spine and sutural side of inner spine from smooth to bearing small teeth or denticles, sometimes sutural side slightly curved to outside, even extending to half of the elytral apex (type of C. hastanus oberthueri Lewis. Fig. 2D). Distribution. Bhutan, Burma, China (Fujian, Guizhou, Sichuan, Taiwan, Yunnan), India, Indonesia (Ceram), Japan, Laos, Nepal, Philippines (Luzon, Mindanao, Negos, Palawan, Polillo, Samar), Thailand, Vietnam. Remarks. Based on the results of our study, two species can be distinguished by the characters as follows: (1) habitus—C. hastanus slender and longer than C. ephippiatus; (2) elytra—in C. hastanus elytral apex wider and more deeply emarginate, lateral margin relatively straighter towards posterior 1/3 than in C. ephippiatus; (3) coloration—C. hastanus is lighter, varying from golden-cooper to blue, while C. ephippiatus is green with blue tinge; (4) aedeagus of C. hastanus is narrow, subparallel (Figs. 8F, 8G), not dilated as that in C. ephippiatus (Figs. 4A, 8B).

Discussion

Three subspecies of C. hastanus were divided into two species based on characters analyzed by morphometrics and distribution patterns. Many characters of Coraebus show high variability, slightly differing among the individuals, e.g. C. cloueti Théry, 1895 (Kubáň, 1995). The following questions are faced by many taxonomists interested in Buprestidae: how to interpret the morphological characters and how much the variability in characters at the species level can be seen. It is expected that the analysis of character states based on morphometrics can help us to better understand the morphological variability of infraspecific forms. The character of the elytral apex is very important in distinguishing the species of Coraebus (Descarpentries & Villiers, 1967). It is relatively stable at the species level, but in some species like C. hastanus, the elytral apex is highly variable. Even in the same specimen, the apex of each elytron can be distinctly different, so the taxonomic value of this character needs further investigation, especially among very closely related species. Shape analysis plays an important role in many kinds of biological studies. Traditional morphometrics is limited by giving little information about shape. Geometric shape analysis has a tremendous advantage in offering precise and accurate description of morphological structures. During the study of the morphological variability of C. hastanus, the advantage of geometric shape analysis

188 · Zootaxa 3682 (1) © 2013 Magnolia Press XU ET AL. was proved again. Variability of the lateral margins of elytra and aedeagus is so subtle that we can not evaluate the difference among species using simple observation. Geometric shape analysis successfully provided a trend of the variation. It is suggested that the traditional morphometric approach plays important role in understanding morphological variatiability in general, while the geometric morphometric approach is a useful complementary tool for discriminating the subtle difference among the species. Morphological infraspecific variability can be associated with different habitats or host plants. Some buprestids demonstrate more or less distinctive ecological forms of unclear taxonomical level on the different host plants, such as Agrilus viridis (Linnaeus, 1758), one of the most variable buprestids, showing wide variability in size and coloration, also in structure of pronotum and shape of elytra, even aedeagus varies depending on the host plant (Alexeev, 1969; Hodge, 2006; Bernhard et al, 2005). According to the work of Holt et al (2012) on the zoogeographic regions of the world, C. ephippatus could have originated in the Sino-Japanese region, and spread towards the Oriental region, and C. hastanus could have originated in Oriental region, and spread towards the Sino-Japanese region, their ranges overlapping along the border between these two zoogeographic regions. Morphological variability between the species is probably a result of secondary overlap of the primarily isolated geographic ranges or a region of hybridization. Molecular biology would provide good means to understand the morphological variability. Having only limited material and knowledge of biology, we can not analyze molecular data and ecological factors, such as host plant associations, altitude preference, etc. Additional material and information are necessary for better understanding the morphological variability among Coraebus species.

Acknowledgements

We sincere thank all our colleagues for their kind help, giving us a chance to study the materials from different Museums. Particular thanks to Maria Lourdes Chamorro (Systematic Entomology Laboratory, ARS, USDA, Washington, D.C., U.S.A.), for sponsoring study of two senior authors at the USNM; Guodong Ren, Fuming Shi (HBUM) and Zhongliang Peng (JSNC) for loan numerous specimens for study; Antoine Mantilleri (MNHN), Max V.L. Barclay and Malcolm D. Kerley (BMHN) for loan type specimens and taking images; Alex Konstantinov (Systematic Entomology Laboratory, ARS, USDA, Washington, D.C., U.S.A.) for helping with the manuscript and giving us valuable advice in the course of this study, and Huaijun Xue (IZAS) for giving advice too. This research was supported by the National Basic Research Program of China (973 Program) (No. 2011CB302102), the National Natural Science Foundation of China (Nos. 31010103913, J1210002), the Knowledge Innovation Program of Chinese Academy of Sciences (Nos. KSCX2-EW-G-4 and KSCX2-EW-Z-8) and by the institutional support from Ministry of Culture of the Czech Republic to National Museum (DKRVO 2013/12, 00023272) (VK).

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