A new Eastern Asian Hycleus and key to the Chinese species of the phaleratus group (Coleoptera, Meloidae, Mylabrini)

Abstract A new species of Hycleus belonging to the phaleratus group, and close to Hycleus phaleratus, is described. The new species, Hycleus marcipoli, is distributed in China (Gansu and Taiwan), Laos, and northern Thailand. A key to the Chinese species of this group is presented.


Introduction
Hycleus Latreille, 1817, tribe Mylabrini, is the most speciose genus of the blister beetle family with approximately 430 described species. However, the only study of the genus is a very old comprehensive one (Marseul 1872) devoted to the entire tribe. Hycleus itself remains inadequately studied and is in need of complete revision.
The genus is restricted to the Old World and centered in the Afrotropical region (Bologna and Pinto 2002). In the literature it has been confused with the genus Mylabris Fabricius, 1775 and other Mylabrini genera by several Authors. The very complex synonymy and generic definition of Hycleus were explained by Bologna (1978Bologna ( , 1991 and Bologna and Pinto (2002).
The taxonomy of some Palaearctic and Afrotropical species groups have been studied in the last 50 years (e.g. Pardo Alcaide 1954Alcaide , 1955Alcaide , 1958Alcaide , 1968Bologna 1978Bologna , 1979Bologna , 1990Bologna , 1991, while that of the Oriental species is still confused and the scanty contributions provide rough descriptions and figures (Saha 1972(Saha , 1979. Recently, a preliminary taxonomic study of Chinese Hycleus species was published by Pan et al. (2011a, in Chinese); this contribution considered 19 species belonging to both Palaearctic and Oriental lineages. As is widely known, the Chinese area belongs to both biogeographic regions and is also characterized by a transitional biogeographic subregion in its south-eastern portion (e.g., Palestrini et al. 1987;Brown and Lomolino 1998) thus representing a valuable and appropriate research zone.
Several Oriental species of Hycleus belong to the phaleratus group, which is widely distributed from Pakistan to eastern China and Indonesia. The phaleratus group is distinct, but more closely related to Afrotropical than to Palaearctic lineages. It is mostly distributed in the Oriental region and in the transitional biogeographic subregion, and marginally spread in some Palaearctic zones of Mongolia, China, Himalayan countries, India and Pakistan. This group of species belongs to the Hycleus lineage characterized by a mesosternum of the Mesoscutatus type (see Bologna 1991) with a large modified fore area ("scutum"). It is easily distinguishable from other Hycleus belonging to the Mesoscutatus lineage by the following characters: male maxillary galeae not distinctly modified; antennae with 11 antennomeres entirely black (Fig. 3); elytra black with two reddish yellow basal spots (one in the middle and one on the external margin) and two, middle and subapical, yellow-reddish transverse fasciae (Fig. 4).
The species of this group have been repeatedly confused in the literature and the future examination of types will be the basis for a taxonomic revision of all included species. The main taxonomic problem is that Pallas (1782) described "Meloe phalerata" from "cisgangeticae Indiae" (type locality: an old name indicating the Indian regions W of Ganges river), but its collection is missing and no types are currently available. The identification of phaleratus in the literature is doubtful and has always been based on the elytral pattern, which actually is similar in other Oriental species of this group. Considering that this taxonomic problem remains unclarified, in the present paper we defined as phaleratus the species occurring in India; it best corresponds to the Pallas' description.
Working on Chinese specimens of this group housed in the M. Bologna's collection (University Roma Tre: MAB), we discovered a new species not identified in the Pan et al. (2011a, b) studies. Aim of the present study is to describe this new species and to provide a key to the known Chinese species of the phaleratus group. Type locality. "China, Kansu mer. Shinlong-Shan Mts. Yuzhong". Shinlong-Shan Mts., as written on the label, is the transliterated name of the Xinglong-Shan Mts., located in the Yuzhong County, Lanzhou City, in Southeastern part of Gansu Province. These mountains represent the eastward extension of the Qilian-Shan Mts. This area is usually included in the Palaearctic region, but according to its animal and plant diversity, it belongs to the transitional Chinese area.

Hycleus marcipoli
Diagnosis. This is a species of the Mesoscutatus type lineage, belonging to the phaleratus group and phenetically similar to H. phaleratus (Pallas, 1782). Body only with black setae except the elytral axillary fore spot, the protibiae and protarsi with mixed black and yellow-brown setae. Basal part of antennomere XI narrower than the apical part of antennomere X (Fig. 3). Elytral yellow-reddish fasciae wider and slightly flexuous (Figs 1a, 4). Fore margins of mesepisterna forming a median narrow groove, margins almost touching each other (Fig. 5). Apical setae on external side of protibiae distinctly longer than those on other parts of tibia, reaching the apical margin of protarsomere I. Proximal aedeagal dorsal hook positioned far from the distal one (Fig. 6).
Description. Body (Fig. 1a) unicolour black, except elytra, which are black but with two testaceous fore spots (one axillary and one close to the scutellum), two slightly sinuate testaceous fasciae, a medial one and a subapical one (Fig. 4). Body with black setae, also on ventral side, but mixed with golden setae on the elytral axillary fore spot, on inner side of protibiae, and on protarsal pads. Body length (apex of mandibles-apex of elytra): 26-38 mm.
Head subquadrate, slightly longer than wide, with the maximum width at the level of eyes. Punctures shallow, medium in size and quite dense, in some specimens reduced near the frontal suture, with an inconspicuous depression in the middle, between eyes. Eye globose, with the antero-dorsal margin slightly sinuate, just behind the antennal insertion. Temple subparallel, only slightly curved posteriad and subequal in length to the longitudinal diameter of eye. Clypeus, narrower than the interocular width, rounded on sides, posteriorly with same punctures of frons and anteriorly almost smooth and slightly sloping; labrum subreniform, scarcely narrower than clypeus, rounded on sides, the fore margin moderately sinuate in both sexes, medially slightly depressed. Male maxillary galeae non modified in both sexes, laterally and ventrally, with a tuft of elongate robust setae, not thickened, on posterior half; maxillary palpomeres slightly enlarged apically, particularly II and III, palpomere IV suboval; labial palpomere II slightly widening (Fig. 2). Mandibles curved and progressively narrowed on the apical third. Antennae with 11 antennomeres (Figs. 3): I-V more or less shiny, the remaining subopaque; antennomere I ca. as long as II-III together; II subglobose; III-IV subcylindrical and slender, III about 1.5 times as long as IV; V-VIII similar in length, subtrapezoidal, apically enlarged on external side, increasing in width from V to IX and then decreasing from X to XI, X subquadrate and slightly shorter than IX; antennomere XI distinctly narrower and ca 1.5 as long as X, subcylindrical but narrowed in the apical third.
Pronotum elongated, distinctly longer than wide, about as wide as head at eyes, subparallel on sides on the basal 2/3, and then distinctly narrowing anteriad; fore portion greatly depressed, as well as on the middle of base, just in front of mesonotum; punctures similar to that on head, with a longitudinal medial small furrow, almost impunctate. Elytral pattern as in Figs 1a, 4. Mesosternum of the Mesoscutatus-type (Fig. 5); fore margins of mesepisterna forming a median narrow groove, margins almost touching each other. Legs slender; protibiae with two spurs, both tibial spurs on all legs slender; protarsi in both sexes with a distinct golden ventral pad; apical setae on external side of male distinctly longer than those on other parts of the tibia, reaching the apical margin of protarsomere I; external side of male protibiae with scattered longer setae, and inner side on both sexes with dense golden setation. Protarsi as long as protibiae, protarsomeres always longer than wide, slightly widened apically and with dense and longer setae at apex.
Posterior margin of the penultimate male abdominal sternite sublinear, that of the last visible sternite only slightly emarginated. Parameres (Figs 7, 8) distinctly elongate with slender and elongate apical lobes, much narrower than basal third in ventral view; aedeagus with two slender hooks, proximal one positioned far from the distal one (Fig.  6); endophallic hook small and slender.
Etymology. As a tribute to the collaboration established among the authors during the Ph.D. studies made in Italy by one of them (PZ), the new species is named after Marco Polo (1254-1324), the Venetian explorer who, during a long period of permanence in China in the late XIII century (1271-1284), established the first well documented relationships between the Chinese and European worlds and opened western culture to the wide and rich Chinese heritage.
Taxonomic remarks. The species of the phaleratus group are phenetically similar in body shape, but variable in size and elytral colouration; H. phaleratus is the most similar to H. marcipoli. These species have been repeatedly confused due to their similar, but they can be identified by the following characters used in the key below: colour of setae on ventral side of body and on elytral yellow-reddish fasciae and spots, especially the axillary spot; length of setae on male protibiae and protarsi; shape of protarsi, mesosternum, and male genitalia; extension of the fore pronotal depression.
Distribution. China (SE Gansu, Taiwan); Laos; Thailand. Elytral axillary spot with few yellow setae mixed to black setae; setae at external apex of male protibiae longer than those on other sides and reaching the apical margin of protarsomere I; fore margins of mesepisterna forming a median narrow and drop-like groove, margins almost touching each other; proximal aedeagal hook positioned far from the distal one. (Figs 1a and 2 (Pan et al. 2011a, b; note that bistillatus (Tan, 1981), was referred erroneously to Hycleus but actually belongs to the genus Mylabris; Pan et al. in prep.), excluding H. schoennerri (Billberg, 1813) having a Mesogorbatus type mesosternum, the remaining 19 have a Mesoscutus type meosternum. Nine of them belong to Palaearctic lineages and, in particular, the following species can be referred to the polymorphus group (as partially defined by Bologna 1991Bologna , 1994 (Heyden, 1883). The remaining ten Chinese Hycleus with Mesoscutatus mesosternum, here studied, belong to the Oriental phaleratus group.

Key to the Chinese
Other species were described from India and Pakistan in the genus Mylabris (or its synonym Zonabris Harold, 1879) by Pic (1916) and Saha (1972Saha ( , 1979; however, these very short descriptions and rough figures are scarcely informative. According to the descriptions and/or after type examinations, some of these can be referred to the genus Hycleus and a few [ajantaensis (Saha, 1979), goaensis (Saha, 1979), gonostilus (Saha, 1972), himalayaensis (Saha, 1979), horai (Saha, 1972), mandibularis (Saha, 1979), sahai (Kaszab, 1981) new name] may belong to the phaleratus group and mostly are probably synonyms of H. phaleratus, H. biundulatus, H. medioinsignatus and H. cichorii. These species apparently differ from H. marcipoli and were never recorded from China.
The study of new characters useful in the taxonomy of Oriental lineages, such as the morphology of male genitalia, maxillae, palpomeres and mesosternal structure, utilized for the Afrotropical Hycleus, could support the study of Oriental species, never revised in more than one century.