Revision of Taiwanese species of Atrachya Chevrolat, 1836 (Coleoptera, Chrysomelidae, Galerucinae): descriptions of three new genera, two new species, and designations of three new synonyms

Abstract The genus Atrachya Chevrolat is redefined based on study of the type species A. menetriesii (Faldermann, 1835). All Taiwanese species of Atrachya are transferred to three new genera: A. hirashimai Kimoto, 1976 and A. nitidissima (Chûjô, 1935) are transferred to Neochyagen. nov.; A. mediofasciata Kimoto, 1976 is transferred to Tsouchyagen. nov.; A. unifasciata Takizawa, 1978 is transferred to Chinochyagen. nov. Two species are described: N. chengisp. nov. and N. tsouisp. nov.Atrachya bicoloripennis (Chûjô, 1938) and A. saramao (Chûjô, 1962) are regarded as synonyms of N. nitidissima (Chûjô, 1935) comb. nov., and Monolepta tsoui Lee, 2009 is synonymized with T. mediofasciata (Kimoto, 1976) comb. nov.Monolepta sublata Gressitt & Kimoto, 1963 is redescribed and transferred to Chinochyagen. nov. Taiwanese records of Monolepta sublata are based on misidentifications and represent specimens of C. unifasciata. Variablity of adult color patterns is discussed.

Etymology. Composed from new and Atrachya to indicate that this is a new genus similar to Atrachya.
Included species. Neochya chengi sp. nov., N. hirashimai (Kimoto), comb. nov., N. nitidissima (Chûjô) comb. nov., and N. tsoui sp. nov  slightly rounded, apical margin slightly concave; disc with dense coarse punctures, without lateral depressions. Elytra 1.33-1.42 times longer than wide; parallel sided; disc slightly convex, with dense, coarse punctures; apex truncate. Penis    wide, ca. 3.5 times longer than wide; lateral margins parallel from base to middle, then slightly narrowed towards apex, apex broadly rounded; tectum broad from apical 1/6 to middle, apex truncate; slightly and curved at apical 1/3 in lateral view; ventral surface with membranous area from apex to apical 1/3. Endophallic spiculae complex with median endophallic spiculae composed of seven pairs of hooked spiculae, and ventral endophallic spiculae composed of four pairs of hooked spiculae; with one pair of longitudinal rows of hair-like setae and one pair of longitudinal double rows of small stout setae near base. Gonocoxae (Fig. 5F) slender, tightly conjunct from apex to apical 1/3; each gonocoxa with eight setae from apical 1/6 to apex, subapically widened, apex truncate. Ventrite VIII (Fig. 5G) weakly sclerotized except apex, with several long setae at apex, and several long setae at sides, spiculum elongate. Spermathecal receptaculum (Fig. 5H) as slender as pump, apically tapering; pump slender and curved; sclerotized spermathecal duct extremely elongate, but base extremely wide, followed by very short slender tube, then followed with inflated areas. Bursal sclerites reduced.
Variation. Most of specimens from Tahanshan have a distinct color pattern on elytra (Fig. 4D, E): with two pairs of transverse, wide black bands, running from lateral margins, abbreviated before suture, anterior pair near base, posterior pair at apical 1/3 an oblique; with one transverse, broad white band at middle. One specimen from Kenting has much narrower black bands on the elytra (Fig. 4F).
Diagnosis. Neochya chengi sp. nov. is similar to N. nitidissima (Chûjô) in having wide elytra, truncate elytral apices and reduced lateral depressions on the pronotum (Figs 4,9) (narrow elytra, rounded elytra apices and with lateral depression on the pronotum in others (Figs 2D-F, 7) but it differs from N. nitidissima in paralle sided elytra and having coarse punctures on pronotum and elytra ( Fig. 4) (rounded elytra and reduced punctures on pronotum and fine punctures on elytra in N. nitidissima ( Fig. 9)), and parallel sided elytra (rounded elytra in N. nitidissima). In addition, males of both species are separated from others with smooth margin of tectum of the penis (Figs 5C, 10C) (serrate margin of tectum (Figs 8C, 12C), but males of N. chengi differs from those of N. nitidissima with absence of small rounded process on lateral margin of the penis ( Etymology. It is named after Mr. Hsing-Tzung Cheng who was a member of the TCRT and an editor for a series of the books entitled "The Chrysomelidae of Taiwan". The gender is feminine. Distribution. Widespread but scattered in Taiwan (Fig. 6A).
Variation. A distinct color pattern occurs in beetles from the east part of South Cross-Island Highway (南橫公路): general color black; but apical 3/4 of elytra and abdomen yellowish brown ( Fig. 7C-E).
Diagnosis. Neochya hirashimai (Kimoto) is similar to N. tsoui sp. nov. in having slender elytra and lateral depressions on the pronotum (Figs 2D-F, 7) (wide elytra and lacking lateral depressions on the prnotum in others (Figs 4,9), but differs from N. tsoui sp. nov. in having reddish brown pronotum and yellowish brown elytra, or black pronotum, black basal half and yellowish brown apical half of elytra ( Fig. 7) (reddish brown pronotum and elytra in N. tsoui sp. nov. (Fig. 2D-F)). In addition, males of both species are separated from others with serrate margin of tectum of the penis (Figs 8C, 12C) (smooth margin of tectum (Figs 5C, 10C), but males of N. hirashimai differs from those of N. tsoui with the penis widest at middle (Fig. 8C, E) (penis widest at apical 2/5 in N. nitidissima (Fig. 12C, E).
Food plants. Celastraceae: Celastrus kusanoi Hayata (Fig. 1B, C), C. punctatus Thunb. Distribution. Restricted to several places in central Taiwan. Two color patterns are separated in the eastern and western parts of the range (Fig. 6B).
Luperodes saramao. Holotype ♂ ( : 5.8. Pronotum 1.90-1.94 times wider than long; lateral margins slightly rounded, basal margin slightly rounded, apical margin slightly concave; disc with dense minute punctures, but without lateral depressions. Elytra 1.36-1.40 times longer than wide; lateral margins rounded, widest at middle; disc moderately convex, with dense, minute punctures; apex truncate. Penis (Fig. 10C-E) wide, ca. 3.8 times longer than wide; lateral margins rounded, widest at basal 1/3; apex broadly rounded; tectum elongate from apical 1/6 to middle, parallel-sided, apex broadly rounded; slightly and apically curved in lateral view; ventral surface with membranous area from apex to apical 1/4; with one small rounded process on lateral margin at apical 1/4. Endophallic spiculae complex with six or seven pairs of hooked spiculae (visible in dorsal view), one additional pair of hooked spiculae near middle with four or five ventral branches; with one pair of longitudinal rows of hair-like setae and small rounded sclerites near base. Gonocoxae ( Fig. 10F) slender, tightly conjunct from apical 1/6 to middle; each gonocoxa with eight setae from apical 1/6 to apex, subapically widened, apex narrowly rounded, base deeply bifurcate. Ventrite VIII (Fig. 10G) weakly sclerotized except apex, with several short and long setae at apex, and several long setae at sides, spiculum elongate. Spermathecal receptaculum (Fig. 10H) as slender as pump, apically tapering; pump slender and curved; sclerotized spermathecal duct extremely elongate, but base wide, followed by slender tube, then with inflated areas. Bursal sclerites reduced.
Variation. Color pattern divided into four forms. Form A (Fig. 9A, B) (described as one form of Atrachya bicoloripennis): general color black; but apical 2/3 white, abdomen reddish brown. Form B (Fig. 9C, D): similar to form A, but white area replaced with red (described as another form of A. bicoloripennis). Form C (Fig. 9E, F) (described as A. saramao): similar to form B, but elytra entirely reddish brown, meso-and metathoracic ventrites reddish brown; some individuals have paler femora and antennae. Form D (Fig. 9G, H) (described as typical form of A. nitidissima): body color reddish brown, but antennae, tibiae, and tarsi darker. Form E (Fig. 9I): similar to form A, but apical 1/3 of elytra black.
Diagnosis. Neochya nitidissima (Chûjô) is similar to N. chengi sp. nov. in having wide elytra, truncate elytral apices and reduced lateral depressions on the pronotum (Figs 4, 9) (narrow elytra, rounded elytra apices and with lateral depression on the pronotum in others (Figs 2D-F, 7) but differs from N. chengi sp. nov. in rounded elytra and having reduced punctures on the pronotum and fine punctures on the elytra (Fig. 9) (parallel sided elytra and coarse punctures on pronotum and elytra in N. chengi sp. nov. (Fig. 3)). In addition, males of both species are separated from others with smooth margin of tectum of the penis (Figs 5C, 10C) (serrate margin of tectum (Figs 8C, 12C), but males of N. nitidissima differs from those of N. chengi with small rounded process on lateral margin of the penis (Fig. 10C-E) (lacking small rounded process on lateral margin of the penis in N. nitidissima (Fig. 5C-E). Atrachya bicoloripennis (Forms A and B: Fig. 9A-E) and A. saramao (Form C: Fig. 9E, F) have distinct color patterns which are different from typical form N. nitidissima (Form D: (Fig. 9G,  H)). All of they are synonyms with no doubt based on examination of the penis.
Remarks. The holotype of Luperodes nitidissimus was described as a male (Chûjô 1935), but it is actually a female.

Distribution. Widespread in
Diagnosis. Neochya tsoui sp. nov. is similar to N. hirashimai (Kimoto) in having slender elytra and lateral depressions on the pronotum (Figs 2D-F, 7) (wide elytra and lacking lateral depressions on the pronotum in others (Figs 4, 9), but differs from N. hirashimai in having reddish brown pronotum and elytra (reddish brown pronotum and yellowish brown elytra, or black pronotum, black basal half and yellowish brown apical half of elytra in N. hirashimai). In addition, males of both species are separated from others with serrate margin of tectum of the penis (Figs 8C, 12C) (smooth margin of tectum (Figs 5C, 10C), but males of N. tsoui differs from those of N. hirashimai with the penis widest at apical 2/5 (Fig. 12C, E) (penis widest at middle in N. nitidissima (Fig. 8C, E).
Etymology. This new species is dedicated to Mei-Hua Tsou, a member of TCRT and the first to collect this new species.
Pronotum 1.52-1.56 times as broad as long, lateral margins straight, basally narrowed. Disc covered with dense coarse punctures, moderately convex. Posterior half of disc with wide shallow transverse impression. Anterior margin lacking marginal bead, lateral and posterior margins with marginal bead. Anterior and posterior margins without setae, lateral margins with two pairs of setae near base and apex, respectively. Anterior angles moderately swollen, rectangular, posterior angles obtuse angulate, all angles with setigerous pores bearing long pale setae.

Macropterous.
Ventral surface sparsely covered with fine punctures and pale setae. Anterior coxal cavities closed (Fig. 18F). Prosternal process not visible between procoxae. Abdomen simple, posterior margin of last ventrite with two long incisions in males.
Legs slender. All tibiae with one apical spine, the longest spine on metatibia. Protarsomeres I not modified in males. Metatarsomeres I much longer than pro-and mesotarsomeres I, much longer than II and III combined. Claws appendiculate.
Etymology. Composed from Tsou and Atrachya to honor Mei-Hua Tsou, who is a member of TCRT (Taiwan Chrysomelid Research Team) and made great contributions to inventorying the chrysomelid fauna in Taiwan. The gender is feminine.

Tsouchya mediofasciata (Kimoto, 1976), comb. nov.
Atrachya mediofasciata Kimoto, 1976: 6;: 257 (additional records); Kimoto 1991: 15 (additional records). Monolepta tsoui Lee, 2009: 23. syn. nov. Monolepta bicavipennis: Kimoto, 1969  Remarks. This species is described in detail as Monolepta tsoui by Lee (2009). Color patterns of this species are extremely variable. Typical individuals have a yellowish brown body, with wide black bands along the lateral margins and suture of elytra (Fig. 13A), blackish brown antennae, except two basal antennomeres, tibiae, tarsi, metasternum, metepisternum, and epimera yellowish brown. Some have a more yellowish body color (Fig. 13B, C) but with blackish brown antenna, tibiae, and tarsi as typical form. Different degrees of variation exist between both forms, such as slender back stripes along the margin of the elytra (Fig. 13D). Some are similar to the typical form, but the elytra are entirely black (Fig. 13E). Some are entirely black except the yellowish brown abdomen (Fig. 13F, G). In addition, two color patterns have not been studied previously. One is similar to the typical form but with the elytra black except one transverse white band (Fig. 13H). It was described as Atrachya mediofasciata. The other is also similar to the typical form but the elytra black apically (Fig. 13I). In addition, two specimens misidentified as Monolepta bicavipennis have a characteristic color pattern: yellowish brown body but head and prothrax blackish brown, tibiae darker.
Head. Labrum trapezoidal, transverse, with six pores in transverse row bearing pale setae, anterior margin truncate. Anterior part of head short, almost impunctate and glabrous, four setae on anterior margin of clypeus and several setae along anterior margin of anterofrontal ridge. Interantennal space narrow, 0.8-0.9× as wide as diameter of antennal insertion. Frontal tubercles transverse, slightly reduced, glabrous. Vertex smooth and glabrous. Antennae slender, covered with dense setae, antennomere II subequal to III in length; similar in both sexes.
Pronotum 1.62-1.69 times as broad as long, lateral margins rounded, basally narrowed. Disc covered with dense, fine punctures, moderately convex, without transverse impression. Anterior margin lacking marginal bead, lateral and posterior margins with marginal bead. Anterior and posterior margins without setae, lateral margins with two pairs of setae near base and apex, respectively. Anterior angles moderately swollen, rectangular, posterior angles obtuse angulate, all angles with setigerous pores bearing long pale setae.

Macropterous.
Ventral surface sparsely covered with fine punctures and pale setae. Anterior coxal cavities almost closed (Fig. 18B). Prosternal process not visible between procoxae. Abdomen simple, posterior margin of last ventrite with two long incisions in males.
Legs slender. All tibiae with one apical spine, the longest spine on metatibia. Protarsomeres I swollen in males (Figs 16J, K, 17J, K). Metatarsomeres I much longer than pro-and mesotarsomeres I, much longer than II and III combined. Claws appendiculate.
Etymology. Composed from China and Atrachya to indicate the locality of the type species. The gender is feminine.
Diagnosis. Chinochya sublata is similar to C. unifasciata. They cannot be separated based on their external morphology, however, C. sublata (Fig. 16C-E) differs from C. unifasciata (Fig. 17C-E) in genitalic characters as follow: median endophallic spiculae composed of three different pairs of sclerites (only two pairs of sclerites in C. unifasciata); lateral endophallic spiculae transversely arranged (longitudinally arranged in C. unifasciata); ventral bursa sclerite with seven or eight small denticles (13 or 14 small denticles in C. unifasciata).
Remarks. Males are here described for the first time. Types on which the original description was based are all females (Gressitt and Kimoto 1963) Distribution. South China (Fujian, Sichuan, Yunnan).
Diagnosis. Chinochya unifasciata is similar to C. sublata. They cannot be separated based on their external morphology, however, C. unifasciata (Fig. 17C-E) differs from C. sublata (Fig. 16C-E) based on genitalic characters as follow: median endophallic spiculae composed of two pairs of sclerites (three different pairs of sclerites in C. sublata); lateral endophallic spiculae longitudinally arranged (transversely arranged in C. sublata); ventral bursa sclerite with 13 or 14 small denticles (seven or eight small denticles in C. sublata).
Distribution. Widespread but scattered in Taiwan Prothoracic coxal cavities closed (Fig. 18C)  Pronotum and elytra reddish brown (Fig. 2D-F)  Pronotum reddish brown and elytra yellowish brown; or pronotum black and elytra with basal half black and apical half yellowish brown (Fig. 7) (Wagner 2007). However, no endemic genera were known in the eastern Palaearctic region, which includes Taiwan. The present study revealed that high supraspecific diversity may also occur in this area when more species of Monolepta and Atrachya are studied in detail. In addition, a number of genera appear in mainland China, Vietnam, Laos, and Thailand, including Macrima Baly, 1878, Pseudosepharia Laboissière, 1936, and Desbordelepta Nguyen & Gómez-Zurita, 2017. They are awaiting redescription and comprehensive revision. Reliable diagnostic characters for the supraspecific taxonomy of Monoleptites with elongate metatarsomeres I have been limited. Color patterns are useful for most Oriental genera, but not diagnostic for east Palaearctic genera. This character in most species of Neochya and Tsouchya is variable, and in N. nitidissima and T. mediofasciata it is extremely variable. Although color patterns of Chinochya species are similar, some species of Monolepta share these patterns, including M. leechi Jacoby, 1890 and M. maana Gressitt & Kimoto, 1963. Prothoracic coxal cavities have been used for diagnosis of genera within this group of Monoleptites. This character was evaluated in Atrachya menetriesii, all species of Neochya, Chinochya, Tsouchya, Taiwanese species of Paleosepharia, and Monolepta. It can be separated into three states: widely open for Atrachya (Fig. 18A) and Neochya (Fig. 18D), almost closed for Chinochya (Fig. 18B), completely closed for Monolepta (Fig. 18C), Paleosepharia (Fig. 18E), and Tsouchya (Fig. 18F).
Elytral epipleurae of Paleosepharia (Fig. 19C) are abbreviated before the middle and this has been considered diagnostic (e.g., Lee 2018). However, interpreting subtle differences in character states is difficult when comparing it in other related genera (Fig. 19). It is not diagnostic for distinguishing Paleosepharia from others. In addition, few female genitalic characters have been used as diagnostic characters. Spermathecae are poorly illustrated, and abdominal ventrites VIII and gonocoxae were usually ignored in most papers. This study supports the use of these characters as diagnostic provided that descriptions are supported by good quality illustrations.