Aclees aenigmaticus Meregalli & Boriani, 2020

Meregalli, Massimo, Boriani, Marco, Taddei, Andrea, Hsu, Chen-Fu, Tseng, Wei-Zhe & Mouttet, Raphaëlle, 2020, A new species of Aclees from Taiwan with notes on other species of the genus (Coleoptera: Curculionidae: Molytinae), Zootaxa 4868 (1), pp. 1-26 : 5-9

Aclees aenigmaticus Meregalli & Boriani , sp. n.

Figs 2 , 3 , 4 (A, C, E, G, I, K), 5 (A, C, G, I), 6 (A-D) Zoobank.org/ urn:lsid:zoobank.org:act:452B9AAF-B740-4900-A902-4A36ED266217

Material examined. Holotype ♂ ( Fig. 2 ): TAIWAN: “FORMOSA ( TCHAJ-WAN) [= Taiwan ] / Hsinchu County / 20 km NW Neiwan / 28.05.2013 1563 m / N 24.69140 E 121.31076 / Jaroslav DALIHOD leg.” ( NMNS)

Paratypes: TAIWAN: “FORMOSA ( TCHAJ-WAN) [= Taiwan] / Hsinch [= Hsinchu] County / NEIWAN 9.6– 14.6.2007 / Jaroslav DALIHOD leg. / Jana DALIHODOVÁ BAŠTOVA leg.” 1 ♂ ( MER) ; “TAIWAN / Nantou County / Xinyi Township— 18. VI.2019 / Ping-Chun Jou leg.” (in chinese), 1♀ ( TARI) ; same data, 22. V.2019, 1♀ ( TARI) ; Hushan Hiking Trail, Xinyi Distr., Taipei City , Taiwan , 30.VII.2017, Wei-Zhe Tseng leg., 1♀ [sequenced: ex. 10] ( TSE) ; Wuling Farm, Heping Distr. Taichung City, Taiwan , 13.VIII.2019, Sheng-Hung Lin leg., 1♀ [se- quenced: ex. 8] ( TSE) ; Tamkang Farm, Tamsui Distr., New Taipei City, Taiwan , 5.XI.2017, Wei-Zhe Tseng leg., 1♀ [sequenced ex. 2] ( NMNS) ; Lanyu Township, Taitung County, Taiwan , 1–3.VIII.2018, Sheng-Hung Lin leg., 1 ♂ ( NMNS) ; New Taipei City, 5.X.2018, 1♂, Chen-Fu Hsu leg. [sequenced: ex. 1] ( BOR) ; New Taipei City, 5.X.2018, 1♀, Chen-Fu Hsu leg. ( BOR) ; Taipei City , 11.IX.2016, 1♀, Kuang-Ping Yu leg. [sequenced: ex. 3] ( BOR) ; Taipei City , 29.IX.2016, 1♀, Chen-Fu Hsu leg. [sequenced: ex. 4] ( BOR) ; Nantou County—IX.2016, 1♀, local collector leg. [sequenced: ex. 7] ( BOR) ; New Taipei City, 21.VIII.2015, 1♂, Chen-Fu Hsu leg. [sequenced: ex. 9] ( BOR) .

VIETNAM: Yên Bái, Mù Cang Ch ải [21°51’10”N 104°05’01”E], 1.700 m, VIII.2018, 1♂, local collector leg. [sequenced: ex. 5] ( BOR) . CHINA, Sichuan: CHINA, Sichuan prov., Mount Qingcheng , 725m, N 30°53.770’ E 103°34.690’, 11–16-V-2017, 1♂ Walter Grosser leg. [sequenced: ex. 6]; same data, 2♂ 1♀ (1♂ 1♀ MER, 1♂ PAL) .

Non-type specimens: China, Yunnan: W of Yunnan, N of Nujiang valley, Mt. Biluoxueshan [26°46’60” N 99° 0’ 0” E], 2100m, 2018.6–7, 1♂, Lina Xu leg. [sequenced: ex. 11] ( MER) ; China, Guangxi: CHINA-Guangxi, Nanning, Jiangxi Zhen, Mount Dawangling , 16–29. V . [20]14, 22.670395°N 108.122186°E, Lifeng Wang leg., 3♂ 4♀ ( MER) .

Measurements of the holotype. Body length without rostrum 16.8 mm. Rostrum, length from apex to interocular pit 5.1 mm; width, interantennal 1.12 mm, width at base 1.41 mm; interocular width 0.67 mm. Pronotum, length 5.20 mm, width 5.41 mm. Elytra, length 11.01 mm, width 5.46 mm.

Description. Body oblong, almost black, moderately glossy, integument minutely reticulate. Rostrum slender, dorsal margins slightly and linearly convergent from base to antennal insertion; dorsum slightly convex, with dense round punctures, irregularly aligned in longitudinal rows, leaving a smooth irregular unpunctured median line, often two adjacent punctures merged in oblique deep pits, interspaces of punctures with sparse minute secondary punctation; dorso-lateral margins obtuse, with a few punctures sparsely and irregularly impressed; lateral sides above scrobes with a slightly curved longitudinal furrow, formed by deeply impressed punctures partly merged in groups; surface at antennal insertion with a narrow medial impressed line, triangularly opened forwards, apical part minutely and densely punctured; upper margin of scrobe obtusely convex, with shallowly impressed sparse punctures, upper part of upper margin curved upwards in front of eyes, joined basad to dorso-lateral margin, surface in front of eye densely punctured; vestiture composed of hair-like recumbent light yellowish setae, inserted on basal part of punctures and directed forwards, usually as long as a puncture; setae on sides inserted on basal part of punctures and directed upwards; rostrum in lateral view moderately curved, slightly more curved at antennal insertion; pregenae sparsely and finely punctured; underside in ♂ with dense recumbent yellowish setae, almost absent in ♀. Antennal scape slender, moderately thickened apicad; funicle antennomeres 1 subglobose or subconical, short, thick, as long as wide, 2 conical, 1.5x as long as wide, 3-6 transverse, progressively shorter and more transverse, 7 slightly larger and finely setose; club antennomere 1 as long as wide, sides very feebly and linearly broadened apicad, apparent antennomere 2 (2+3 fused) ogive-shaped, 2.5 as long as wide. Scrobe narrow, linearly directed towards lower part of eye. Head globose, finely punctured; vertex with deep interocular pit. Eyes slightly and regularly convex, elliptical, lower margins narrowed on underside of head, each with>500 very small ommatidia aligned in oblique rows of about 20 ommatidia each. Pronotum globose, slightly transverse, weakly convex, as long as wide or slightly transverse, sides curvilinear, feebly broadened from base to basal third, then very regularly rounded apicad, maximum width at basal quarter, sides more sharply constricted apicad, apex almost half as wide as base; base bisinuate, gently rounded towards scutellum; sculpture on dorsum composed of deep round punctures, in basal half most punctures individually impressed, irregularly aligned in oblique or slightly curvilinear or concentric rows, rows separated by irregular glossy lines, sometimes more raised and broadened, flattened, mainly on dorso-lateral part, external margin of puncture obtusely raised, particularly on sides, forming small conical humps laterally prominent in dorsal view, anterior part of pronotum on dorsum with punctures smaller, dense and irregularly impressed; vestiture composed of very short microscopic setae inserted on external or lower margin of punctures. Elytra oblong, at base almost 1.3x as wide as pronotum at base, humeri slightly prominent, sides almost subparallel, with a low enlargement just after humeri visible from above, then feebly narrowed up to apical third, regularly curved to apex; striae broader than intervals from base to beginning of declivity, progressively narrower towards apex, with round or subrectangular deeply impressed punctures, progressively shallower after midlength and apicad, quite evenly spaced, stria 1 and 2 with approximately 25 punctures from base to apex, and about 12-14 on dorsal part, interspaces between punctures narrower than punctures, smooth and flat, particularly on dorsal part of striae 1 and 2, striae 8 and 9 with punctures smaller, denser; intervals narrow, linear on dorsum, interval 3 generally weakly convex, lateral intervals narrower, convex; vestiture composed of sparse short and scarcely visible, narrow, white-yellowish scales, spaced, aligned in one row on intervals, more frequent on intervals 5 and 7, punctures with a minute seta inserted on base, shorter than puncture. Femur strongly thickened medially, with a sharp tooth bearing a few setae, integument smooth, with slender elliptical, acutely pointed yellowish scales adherent to integument, inserted in a minute pore; tibia relatively slender, inner margin slightly sinuate, with sparse scales similar to those on femur. Tarsomere 2 triangular, as long as wide, tarsomere 3 broadly lobed. Ventrites 1-4 smooth, matt, 1-2 with very minute sparse punctures, 3-4 with in addition round punctures in lateral part, ventrite 5 more densely punctured; all ventrites with sparse very slender yellowish scales inserted in the minute punctures. Penis in lateral view moderately curved, thick, in dorsal view sclerotized lateral margins subparallel, weakly broadened before ostium, lamella shortly triangular, obtusely pointed, slightly curved upward, endophallus with a complex structure when everted (see caption of Fig. 3 for the abbreviations): bl small, in dorsal view simple, ul large, cylindrical, elongate, in dorsal view with two narrow and short subapical lateral projections, in frontal view apex distinctly prominent, with some transverse lateral furrows, mb shorter than ul, densely covered with spicoles, not broadened below ul in frontal view, la slender, conical, weakly curved upwards, shorter than ul. Female sternum VIII linear, very slender, arms subparallel in basal part, slightly divergent at apex, lamina reduced to a very narrow rounded plate.

Sexual dimorphism. The male ventrites 1 and 2 have the usual very shallow median impression, that, as is typical of the genus, is scarcely developed. The male has the rostrum slightly matt in the apical part, and its underside has a series of relatively dense setae from almost the apex to near the base; the female has the rostrum glossy to the apex and slightly more slender, with very few setae on the underside.

Variation. The specimens examined show some variation, mainly regarding the shape of the pronotum and the density of its punctures. In some specimens the pronotum can be slightly less robust, with its sides scarcely curved, and the round punctures in the basal half can be denser, merged in short grooves rather than individually impressed. Some specimens from China (Sichuan, Guangxi and Yunnan) and Vietnam are not morphologically differentiated from those from Taiwan, neither in external morphology, nor in the shape of the endophallus. One specimen from Vietnam and one from Sichuan clustered together with those from Taiwan in the BI, and they have a p-distance in the mt-cox1 sequences around 0.01. One specimen from Yunnan has a p-distance of about 0.023 –0.029 from the other specimens, and it clustered as the sister to them. This appears to be a distinct metapopulation, and this specimen is excluded from the type series, such as those from Guangxi, whose sequences were not available .

Differential remarks ( Figs 4 , 5 ). Aclees aenigmaticus is morphologically similar to the sympatric A. taiwanensis and some female specimens are not easy to distinguish. The males can be immediately differentiated ( Fig. 4 ) by the shape of the lamella of the penis, short (ratio length/width 0.60), with slightly sinuate sides and shortly rounded apex in A. taiwanensis and slenderer (ratio l/ w 0.70), triangular, with straight sides and obtusely acute apex in A. aenigmaticus . The endophallus is completely different between the two species: in A. taiwanensis bl is large, in dorsal view bilobate, ul is blunt, in frontal view its apex is broadly three-lobate, mb are broadly enlarged below ul, and almost touching internally, la are longer than ul, recurved upwards at 180° at apex (see description for the shape of the endophallus in A. aenigmaticus ). The female genitalia are almost indistinguishable between the two species. The external morphological characters ( Fig. 5 ) are not always decisive, but in doubtful cases valid information is given by the elytral scales and setae. In A. aenigmaticus the scales on the elytra are narrowly elliptical, spaced and quite uniformly inserted in a single row on the intervals, whereas in A. taiwanensis they are very long and acutely lanceolate, glossy yellow, irregularly spaced, here and there denser, and, mainly on the intervals 4-7 in the median part of the elytra, often 3-4 scales are sparsely grouped; some minute extremely short hair like setae are also present, intermixed with the scales. In A. aenigmaticus the pronotum is usually more globose, slightly convex and often with slightly rounded sides and maximum width in basal quarter, whereas in A. taiwanensis it is never globose, and its sides are linear in the basal part, with the maximum width at the base; the pronotal punctures in A. taiwanensis are usually almost completely merged in short grooves, the interspaces among them are irregularly vermiculate, slightly convex, and often in the apical part there is a flattened area with small, sparse punctures, whereas in A. aenigmaticus the punctures are large, in some specimens almost all individually impressed in the central-basal part; when partially merged in short grooves, these are usually aligned to form short oblique or semicircular grooves, and near the apical margin they are usually large, irregularly impressed; in A. taiwanensis antennomere 1 of the funicle is a bit more elongate and subconical and antennomere 1 of the club has slightly curvilinear sides (sides linear in A. aenigmaticus ); the elytral punctures are densely impressed in A. aenigmaticus , where they are usually more numerous, approximately 25 punctures are present in the striae 1 and 2 from base to apex, with about 12-14 punctures on the dorsal part, whereas in A. taiwanensis there are usually about 20 punctures, 8-10 on the dorsal part. As a consequence, the interspaces between two punctures are as long as a single puncture in A. taiwanensis and usually shorter than a single puncture in A. aenigmaticus . The third species present in Taiwan, A. hirayamai , cannot be confused. It belongs to the A. juvencus Faust, 1892 group and as such it has finely and densely punctured rostrum, distinctly transverse pronotum with quite regularly impressed smaller punctures and the male and female genitalia are completely different. Among the other described species of Aclees , a densely and deeply sculptured pronotum is present in A. cribratus Gyllenhal, 1835 , A. pseudocribratus Osella 1989 , A. foveatus Voss, 1932 , and A. conicollis Desbrochers, 1891 . The former species, described from Java, has the elytral punctures subquadrate, the intervals are narrow, slightly convex and the interspaces between the punctures are as high as the intervals, so that the elytra have a cribrate aspect. The other three species, described from Pakistan ( A. pseudocribratus ), China ( A. foveatus ) and Sikkim ( A. conicollis ) have the sides of the pronotum not rounded in the basal and median parts but parallel or subconical, and the punctures are usually not individually impressed. The rostrum in A. foveatus is shorter, with ratio length/width 3.15 (ratio length/width 3.5 in A. aenigmaticus ) (female specimens). A further species of Aclees was described from China, A. davidis Fairmaire, 1878 . However, according to the author, this species has small patches of scales on the elytra, including on the scutellum, and therefore it is doubtful that it belongs to the genus Aclees .

Distribution. The species is known from Taiwan, China (Guangxi, Sichuan, Yunnan) and Vietnam. More specimens are required to have a better understanding of the distribution of the species and to fully understand the relationships among the populations, with particular regard to those from China.

Origin of the name. The species is named aenigmaticus , enigmatic, because of the past uncertainties about its identification and the difficult differentiation from the morphologically similar species.

Bionomy. No precise information is available. In general, there is no information on the ecology and mating behavior for the majority of Aclees species. However, in Japan, Taiwan and China, larvae of A. hirayamai feed on Ficus erecta Thunberg and F. elastica Roxb. , creating serious damage in nurseries of these ornamental plants ( Morimoto 1982). In Taiwan Aclees spp. are found on Ficus ampelas Burm. fil., F. recurva Blume (= F. microcarpa Bl. ), F. pumila L. and Broussonetia papyrifera Vent. (Hsu, pers. comm.). One of the specimens of A. taiwanensis used in this study was found on Ficus beecheyana Hook. &Arn. (Tseng, pers. obs.). A species of Aclees was reported to damage fig cultivations in China, Sichuan (Jiaxiang County Xinhe Fig Planting Professional Cooperative 2018). Not all species of the genus are associated with Ficus . Aclees sp. (as A. porusus sensu auctorum, non Pascoe, 1871), was observed to attack terminal shoots of Breadfruit [ Artocarpus altilis (Parkinson) Forsberg ], causing considerable damage ( Pemberton 1954). The record of an unidentified Aclees- species, pest of Cedrela odorata L., ( Meliaceae ) in Vietnam ( Thu et al. 2010) must be referred to a species of Dysceroides , possibly D. longiclavis (Marshall, 1924) , based on the photograph included in the paper.

Figures

FIGURE 2. Aclees aenigmaticus sp. n. Holotype. Bar: 10mm.

FIGURE 3. Aclees aenigmaticus sp. n. Paratype, China, Sichuan. Structure of the endophallus. bl = basal lobe; ul = upper lobe; mb = median branches; la = lateral arms; ll = lower lobe; h = hook; ap = apex of penis.

FIGURE 4. Aclees aenigmaticus sp. n. Paratype, Taiwan. Penis, dorsal view (A), profile (E); apex of penis (C); everted endophallus, profile (G), dorsal view (I), frontal view (K). Aclees taiwanensis Kôno, 1933, Taiwan. Penis, dorsal view (B), profile (F); apex of penis (D); everted endophallus, profile (H), dorsal view (J), frontal view (L).

FIGURE 5. Aclees aenigmaticus sp. n. Paratype, Taiwan. Pronotum (A), elytra (C), detail of elytral scales and setae (G), antenna (E), ventrites (I); Aclees taiwanensis Kôno, 1933, Taiwan. Pronotum (B), elytra (D), detail of elytral scales and setae (H), antenna (F), ventrites (L).