Gonioctena (Brachyphytodecta) scutellaris Baly, 1862

Lee, Chi-Feng & Hsieh, Chia-Hung, 2022, Integrative taxonomy of the leaf-beetle genus Gonioctena Chevrolat, 1836 in Taiwan (Coleoptera, Chrysomelidae, Chrysomelinae, Gonioctenini) reveals new synonymies and one new species, ZooKeys 1120, pp. 1-46 : 1

Gonioctena (Brachyphytodecta) scutellaris Baly, 1862 stat. rev.

Figs 8A-C , 9A-C , 10 , 11

Gonioctena scutellaris Baly, 1862: 27 (North China); Gressitt and Kimoto 1963: 364 (as synonym of G. fulva ; misidentification).

Phytodecta (s. str.) scutellaris : Weise 1916: 181 (catalogue).

Phytodecta scutellaris : Chen 1934: 73.

Asiphytodecta scutellaris : Chen and Young 1941: 206 (key)

Gonioctena thoracica Baly, 1862: 27 (North China); Gressitt and Kimoto 1963: 364 (as synonym of G. fulva ; misidentification). Syn. nov.

Phytodecta (s. str.) thoracicus : Weise 1916: 181 (catalogue).

Phytodecta thoracicus : Chen 1934: 73.

Asiphytodecta thoracicus : Chen and Young 1941: 206 (key)

Gonioctena dichroa Fairmaire, 1888: 153 (China: Jiangxi); synonymized with P. thoracicus by Chen (1934). Synonym confirmed

Phytodecta (s. str.) dichrous : Weise 1916: 181 (catalogue).

Phytodecta (Asiphytodecta) issikii Chûjô, 1958: 69 (Taiwan). Syn. nov.

Gonioctena (Asiphytodecta) issikii : Kimoto 1969: 22 (additional records in Taiwan)

Gonioctena (Brchyphytodecta) issikii : Gruev 1989: 54; Kimoto and Chu 1996: 53 (catalogue); Kimoto and Takizawa 1997: 369 (catalogue).

Gonioctena issikii : Takizawa et al. 1995: 7 (additional records in Taiwan)

Gonioctena (Brchyphytodecta) foochowensis Gruev, 1989: 53 (China: Fujian); Ge 2010: 66 (as synonym of G. fulva ; misidentification). Syn. nov.

Types.

Gonioctena scutellaris . Lectotype ♂ (NMHUK, here designated to clarify its identity among other synonyms): "Type [h, w] // Type / H. T. [p, w, circle card with red border] // Baly Coll. [p, w] // Gonioctena / Gonioctena scutellaris / Baly / N: China [h, b]".

Gonioctena thoracica . Lectotype ♂ (NMHUK, here designated for clarifying its identify with other synonyms): "(aedeagus preserved inside a small container) // Type [h, w] // Type / H. T. [p, w, circle card with red border] // Baly Coll. [p, w] // Gonioctena / Gonioctena thoracica / Baly / N: China [h, b] // Gonioctena / Gonioctena thoracica Baly [h] / det. H.W. Cho 2013 [p, w] // SYN- / TYPE [p, w, circle card with blue border]". Paralectotype: 1♀ (NMHUK): "Type [h, w] // Baly Coll. [p, w] // SYN- / TYPE [p, w, circle card with blue border]".

Gonioctena dichroa . Syntypes: 1♂ (MNHN): "MUSEUM PARIS / KIANG-SI / A. DAVID 1875 [p, w] // 406 / 75 [h, w, circle label] // Gonioctena / Gonioctena dichroa / m. [h, w] // TYPE [p, w, red letters] // SYNTYPE [p, r] // Gonioctena / Gonioctena dichora Frm. / rev. M. Daccordi, 2005 [p, w] // Gonioctena Gonioctena dichora / Fiarmiare, 1888 / det. H.W. Cho 2014 [p, w] // MNHN, Pairs / EC14213 [p, w]"; 1♀ (MNHN): "MUSEUM PARIS / KIANG-SI / A. DAVID 1875 [p, w] // 406 / 75 [h, w, circle label] // 288 [h, green label] // SYNTYPE [p, r] // Gonioctena Gonioctena dichora / Fiarmiare, 1888 / det. H.W. Cho 2014 [p, w] // MNHN, Pairs / EC14214 [p, w]". Fairmaire (1888) indicated that this species was described in Beijing (= Pekin) but both types actually were collected from Jiangxi (= Kiang-Si).

Phytodecta (Asiphytodecta) issikii . Holotype ♂ (TARI, original designation): "Baibara [h] (= Meiyuan, 眉原) / FORMOSA [p] / 24.III.1943 [h] / COL. [p] S. Issiki [h, w] // Phytodecta / Phytodecta issikii / / Chûjô [h] / DET. M. CHUJO [p, w] // Holo / Type [h, w; circle card with red letters and border but fade out] // 695 [p, w]".

Gonioctena (Brchyphytodecta) foochowensis . Holotype ♀ (NMHUK, original designation): "CHINA / Foochow / C. R. Kelloqq [h, w] // Field No. [p] / 980 [h, w] // Phytodecta / sp [h] / Det. G. E. Bryant. [p] // Brit. Mus. / 198[p]1-315 [h, w] // Gonioctena / Gonioctena foochowensis / Gruev [p, w] // HOLOTYPE [p, r] // Gonioctena dichroa / Fairmaire, 1888 / det. H.W. Cho 2014 [p, w]".

Other material (n = 150).

China. Fujian: 5♂, 8♀ (NMHUK), Foochow (福州), 1935-1938, leg. M. S. Yang ; Taiwan. Nantou: 2♂, 1♀ (TARI), Lienhuachih (蓮華池), 28.IV.2016, leg. A. Li ; Kinmen: Kinmen Island (金門): 14♂, 7♀ (TARI), Tsaitso trail (蔡厝古道), 20.IV.2021, leg. C.-F. Lee ; 4♂, 1♀ (TARI), Taiwushan (太武山), 14.IV.2011, leg. Y.-J. Chang; 1♀ (TARI), same but with “6.V.2011”; 5♂, 2♀ (TARI), same but with “19.IV.2015”; 2♂, 4♀ (TARI), same but with “29-30.IV.2015”; 24♂, 23♀ (TARI), same locality, 8.IV.2021, leg. C.-F. Lee ; 23♂, 27♀ (TARI), same but with “15.IV.2021”; Dadan Island (大膽島): 1♀ (TARI), 9.V.2016, leg. Y.-J. Chang ; Matsu Islands: 1♂, 2♀ (TARI), Beigan Island (北竿), 1.V.2018, leg. H.-T. Fang ; 1♂ (TARI), Nangan Island (南竿), 24.V.2009, leg. U. Ong.

Redescription.

Length 5.3-6.4 mm, width 3.5-4.0 mm. Body color (Fig. 8A, B ) yellowish brown; antennomeres V-XI, legs, and scutellum black. Antennae (Fig. 10A ) with antennomere III slender, IV-VI slightly swollen, VII moderately swollen, VIII-X strongly swollen, XI elongate oval, length ratios of antennomeres I-XI 1.0: 0.6: 0.6: 0.4: 0.4: 0.4: 0.5: 0.5: 0.5: 0.5: 0.9, length to width ratios of antennomeres I-XI 2.3: 1.9: 2.4: 1.7: 1.6: 1.0: 1.1: 1.1: 0.9: 0.9: 1.7. Pronotum 2.2-2.3 × wider than long, lateral margins widest at base, convergent anteriorly, anterior angles strongly produced; anterior and lateral margins bordered, lateral margins barely visible in dorsal view; trichobothria absent on both anterior and posterior angles; disc covered with sparse fine punctures and mixed with finer punctures; both sides covered with much larger, denser punctures. Scutellum distinctly wider than long, narrowed posteriorly. Elytra 1.1-1.2 × longer than wide; lateral margins slightly wider posteriorly, widest near middle; humeral calli well developed; disc covered with rather regular coarse punctures arranged into single stria; interspaces covered with fine, sparse punctures. Hind wing well developed. Aedeagus (Fig. 10B, C ) with apical process extremely slender and elongate in dorsal view, 0.5 × as long as aedeagus; lateral margins slightly narrowed in basal 1/3; strongly curved at basal 1/3 in lateral view; endophallic sclerite extremely elongate. Gonocoxae (Fig. 10D ) wide, but apical margin irregular, with several long setae along apical margins. Ventrite VIII (Fig. 10E ) transverse, with several long setae along outer margin. Receptacle of spermatheca (Fig. 10F ) slightly swollen, not separated from pump; pump short and curved; sclerotized proximal spermathecal duct moderately short.

Variations.

Many adults possess black elytra with wide yellowish brown borders (Fig. 9A-C ) that were described as Gonioctena foochowensis and G. issikii . Some with the elytra entirely black were described as G. dichroa (Fig. 8C ) and G. thoracica .

Diagnosis.

Gonioctena (Brachyphytodecta) scutellaris can be distinguished from the other consubgeneric species, G. (B.) liui sp. nov. by the following combination of the characters: yellowish brown head and pronotum (Figs 8A, C , 9A ), thoracic and abdominal ventrites (Figs 8B , 9B ) (black head and most parts of pronotum (Fig. 9D ), thoracic and abdominal ventrites (Fig. 9E ) in G. (B.) liui sp. nov.), extremely elongate apical process of aedeagus (Fig. 10B, C ) (short, wide apical process of aedeagus in G. (B.) liui sp. nov. (Fig. 12B, C )), and wide gonocoxae covered with more setae (Fig. 10D ) (narrow gonoxae covered with fewer setae in G. (B.) liui sp. nov. (Fig. 12D )).

Host plants.

Fabaceae : Callerya reticulata (Benth.) Schot (new record, present study)

Biology.

Gonioctena (Brachyphytodecta) scutellaris are presumed to be multivoltine during spring and females are oviparous. In Taiwan, this species seems rare due to unpredictable sprouting times of host plants. Mr. Alex Li (李志穎) collected some adults (Fig. 11F ) and mature larvae on April 28, 2016, at Lienhuachih (蓮華池). However, we could not find this species around the same season in the following years because host plants had not sprouted. For example, we could not find sprouts of the host plants in late May 2021 at that location. The populations in small islands are more stable, where host plants began to sprout, and overwintered female laid eggs during middle of March 2021 in Kinmen Islands. They laid 12 eggs into two rows on very young leaves (Fig. 11A ). Larvae hatched in three-four days. Early instar larvae (Fig. 11B ) fed gregariously on young leaves but became solitary as they matured. The larval duration was nine days. Mature larvae (Fig. 11C ) burrowed into soil and built underground chambers for pupation. Duration of the pupal stage (Fig. 11D ) was nine days. The newly emerged adults (Fig. 11F ) appeared during early April and females started to lay eggs after a week. In Jiangxi, China, females began to lay eggs first and then laid larvae in early April ( Zhang and Shen 1984).

Remarks.

Chen (1934) regarded G. dichroa as synonym of G. thoracica . Gressitt and Kimoto (1963) synonymized G. thoracica and G. scutellaris with G. fulva . Ge (2010) treated G. foochowensis as a synonym of G. fulva . After examining aedeagi of these species, we concluded that G. scutellaris is a distinct species, which is removed from synonymy with G. fulva . Moreover, G. dichora , G. thoracica , and G. foochowensis are conspecific with G. scutellaris . We found that G. issikii is also a junior synonym of G. scutellaris . The typical color form (entirely yellowish brown elytra) is extremely rare in Kinmen and Matsu islands, and Taiwan. Only three specimens of such form were collected from Kinmen Island (金門島) and Dadan Island (大膽島). Many larvae were brought from Kinmen Island into the laboratory for rearing during March 2021. Only one specimen with the typical color form was among more than 50 adults reared from larvae. In addition, although no specimens of this form were collected from Taiwan, photographs of this form were taken at Darken (大坑), Taichng in May 1, 2020 (Fig. 11E ) by Hsien Chung Liu (劉獻宗).

Distribution.

China, Taiwan, including Kinmen Islands (Kinmen Island 金門島, Dadan Island 大膽島) and Matsu Islands (Kaoteng Island 高登島, Beigan Island 北竿島, and Nangan Island 南竿島, new records).

Figures

Figure 8. Habitus of Gonioctena (Brachyphytodecta) scutellaris Baly and G. (B.) fulva (Motschulsky) A G. (B.) scutellaris, typical form, dorsal view B ditto, ventral view C same species, color variation, syntype of G. dichroa Fairmaire D G. (B.) fulva, dorsal view E ditto, ventral view F ditto, lateral view.

Figure 9. Habitus of Gonioctena (Brachyphytodecta) scutellaris Baly and G. (B.) liui sp. nov. A G. (B.) scutellaris, color variation, from Taiwan, dorsal view B ditto, ventral view C ditto, lateral view D G. (B.) liui sp. nov., dorsal view E ditto, ventral view F ditto, lateral view.

Figure 10. Diagnostic characters of Gonioctena (Brachyphytodecta) scutellaris Baly A antenna B aedeagus, dorsal view C aedeagus, lateral view D gonocoxae E abdominal ventrite VIII F spermatheca.

Figure 11. Natural history of Gonioctena (Brachyphytodecta) scutellaris Baly on host plant, Callerya reticulata (Fabaceae) A eggs B first- and second-instar larvae C fourth-instar larva D pupa E adult, typical form, from Daken (大坑), Taichung F adult, color variation, from Lienhuachih (蓮華池), Nantou.

Figure 12. Diagnostic characters of Gonioctena (Brachyphytodecta) liui sp. nov. A antenna B aedeagus, dorsal view C aedeagus, lateral view D gonocoxae E abdominal ventrite VIII F spermatheca.