Taxonomy of the Indo-Malayan presocial potter wasp genus Calligaster de Saussure (Hymenoptera, Vespidae, Eumeninae)

The taxonomic history and current taxonomic status of the presocial potter wasp genus Calligaster de Saussure, 1852, at generic and species levels are reviewed. The hitherto-unknown female of Calligaster viridipennis Giordani Soika, 1960, is described based on specimens newly collected in Central and Southeast Sulawesi. A key to species is also provided.


Introduction
Since Williams (1919) described detailed natural history of Calligaster williamsi Bequaert, 1940, under the name of Zethus (Calligaster) cyanopterus de Saussure, 1852, Calligaster wasps have been considered to practice fully progressive provisioning, and thus to be ones of several subsocial or presocial potter wasps (Cowan 1991). The nesting behavior of Calligaster wasps is unique in the Oriental potter wasps in that, as the wasps of the Neotropical subgenus Zethoides of the genus Zethus Fabricius, they make a nest with plant material (leaves cut into small pieces) and that they nest communally with sisters. All these behavioral characters of Calligaster allow us to consider the genus key to our better understanding of evolution of social and nesting behavior in the Vespidae (Cowan 1991).
Furthermore, despite such interesting aspects of Calligaster from the viewpoints of evolution of social and nesting behavior, phylogeny and biogeography, its taxonomy at generic as well as species levels is not yet revised even though such a taxonomic revision would provide us with robust bases for these studies. In the present paper, the history of taxonomy and current taxonomic status of Calligaster at generic and species levels are reviewed, together with a description of the hitherto-unknown female of C. viridipennis Giordani Soika, 1960, and a key to species.

Material and methods
The present study is based on specimens deposited in the collections of the Museum Zoologicum Bogoriense (MZB), Cibinong, Indonesia; Natural History Collection at Ibaraki University (IUNH), Mito, Japan; National Museum of Nature and Science (NMST), Tsukuba, Japan and the Institute of Ecology and Biological Resources (IEBR), Hanoi, Vietnam.
Each species account is accompanied by the original citation; sex(es) and locality(ies), if mentioned, are given together with the repository(ies) of name-bearing type specimen(s) in parentheses. Distributional data are summarized under "Distribution". The acronyms of the type repositories are as follows: BMNH, The Natural History Museum, London; MCZ, Museum of Comparative Zoology, Harvard University, Cambridge, U.S.A; MSNG, Museo Civico di Storia Naturale di Genova Giacomo Doria, Genova; RMNH, Nationaal Natuurhistorisch Museum (formerly Rijksmuseum van Natuurlijke Historie), Leiden, Netherlands; USC, University of San Carlos, Cebu City, Philippines; ZMB, Zoologisches Museum der Humboldt Universität, Berlin.
Morphological characters and marking patterns were observed on pinned-anddried specimens under a stereoscopic dissecting microscope. Male genitalia of some species were dissected, cleared in lactic acid, and observed in glycerin under a stereoscopic dissecting microscope. Line drawings were made by using the drawing tube attached to the microscope. Terminology on morphological characters mainly follows Bohart and Stange (1965), Carpenter and Cumming (1985), that on surface sculpturing follows Harris (1979), and on male genitalia mainly follows Bitsch (2012).

Diagnosis. The genus
Calligaster can be differentiated from any other eumenine genera by the combination of the following characters: labial and maxillary palpus with three and six palpomeres respectively; mid tibia with two spurs; mesepisternum with horizontal suture absent; propodeum with propodeal orifice rounded dorsally, apical valvula short and rounded, and submarginal carina not projecting as pointed lobe above valvula; metasomal segment I petiolate; tergum I in dorsal view abruptly widened laterally shortly after basal slit, then nearly parallel-sided apically, with longitudinal striae; metasomal sternum II with basal fossa; male characters: terminal antennal flagellomere simple; distal lobe of gonocoxite sub-truncated; gonostyle subapically with a tuft of short and thin hairs; basivolsella long and narrow, slightly enlarged at the base, with an obliquely truncated apex. Remarks. Calligaster was proposed by de Saussure (1852: 23, Pl. IX fig. 6) as a genus to accomodate his two species from "Java": Calligaster cyanoptera de Saussure, 1852 and C. hero de Saussure, 1852. Later, he (de Saussure 1855: 115) synonymized C. hero under Zethus gigas Spinola, 1841, which is a South American Zethus species and is now treated as a synonym of Zethus coeruleopennis (Fabricius, 1798) (Bohart and Stange 1965). Although de Saussure (1855) did not refer to the type locality of C. hero given in de Saussure (1852) (= "Java"), it may have been certainly based on an erroneous labeling. Ashmead (1902) designated C. cyanoptera de Saussure as the type species of Calligaster de Saussure, 1852.
The taxonomic status of Calligaster had not been stabilized until Bequaert (1928) reinstalled its generic status; that is, de Saussure (1855) treated it as a division in the genus Zethus; Gribodo (1892), possibly having followed de Saussure (1855), treated Calligaster as a subgenus in the genus Zethus when he described Zethus javanus (=C. cyanopterus); Dalla Torre (1904) treated Calligaster as a genus; and Cameron (1904Cameron ( , 1909 described two species of Zethus, which Bequaert (1928) transferred to the genus Calligaster. But, establishment of the concept of Calligaster currently accepted by most of the vespid taxonomists was of Giordani Soika (1960).

Key to species of Calligaster
As no specimens were available to us, the characters for C. etchellsii and C. zetteli were extracted from Cameron (1909) and Bequaert (1928), and Gusenleitner (2006), respectively. Neither information of the male characters of C. zetelli nor of the female of C. etchellsi is available to us. In Calligaster, we have observed distinct morphological differences between sexes in the head characters, while characters of the mesosoma and metasoma (except for the number of metasomal segments and genital organs) are nearly the same between the sexes. In the following key, sex is specified only for the head characters.

1
Metasomal tergum I other than basal petiolate part in lateral view hardly convex dorsally (Fig. 4)

Diagnosis.
Calligaster cyanoptera is distinguished from its congeners by the combination of the following characters: metasomal tergum I in lateral view moderately convex dorsally, with distinct preapical depression (Fig. 3), in dorsal view nearly parallel-sided, relatively slender, about 2.5 times as long as its maximum width (Fig. 7); female clypeus in frontal view about 1.5 times as wide as high, with ventral margin more or less truncated rather than broadly rounded (Fig. 10); male clypeus in frontal view about 1.5 times as wide as high, with semi-elliptic emargination at ventral margin (Fig. 14); tergum I hardly punctured, so that dorsal striae are more or less conspicuous (Fig. 7).  Remarks. In his monograph on solitary vespid wasps, de Saussure (1852) described Calligaster cyanoptera based on at least two (the body length was mentioned as "20 á 25 mill. [20 to 25 mill.]") females from "Java". The syntypes were indicated to be in "Musée de Leyde" (de Saussure 1852: 24), but no one has referred to the syntypes. Gribodo (1892: 261) described Zethus (Calligaster) javanus based on a single male from "Kaliparè [in Malang] (Giava orientale [East Java])", and van der Vecht (1937: 262) synonymized it under C. cyanoptera, stating "… Gribodo's species is undoubtedly conspecific with C. cyanopterus … the shape of the clypeus is very different in the two sexes". Meade-Waldo (1914: 204) published, as a synonym of C. cyanopterus de Saussure, 1852, "Zethus erythrostomus Cameron", which was actually an unpublished Cameron's manuscript name for a female specimen from Lawang, East Java (Bequaert 1928: 157).
This species have so far been recorded from Sumatra Is. (Gribodo 1892: 260) and Java Is. (de Saussure 1852, Gribodo 1892, van der Vecht 1937, 1938 our own data as listed below), and we herewith firstly record the species from Bali Is. We also collected a couple of nests made on tree twigs along the creek at Baturiti, Bali; their structure is basically the same as that from the south of Garut, West Java, described by van der Vecht (1938). Cameron, 1909: 206 Remarks. This species was described based on a single male specimen from "Kuching, Borneo" in combination with Zethus (Cameron 1909: 206) and Bequaert (1928: 157) moved it to the genus Calligaster. Neither other records of this species have so far been published nor have we collected any wasps of this species in our rather intensive field collection at several places in Kalimantan. Bequaert (1928: 157), having examined the holotype (by monotypy), stated "... quite a distinct species in the shape of the clypeus, which is unusually wide (twice as broad as high) and ends in a deep semi-elliptic emargination." Such a deep semi-elliptical emargination at the ventral margin of the male clypeus is also found in C. cyanoptera, while the male clypeus in the latter is about 1.5 times as wide as high.

Calligaster etchellsii (Cameron, 1909)
Material Diagnosis. The characters which may allow us to differentiate C. himalayensis from C. cyanoptera are as follows [characters for C. cyanoptera are given in the brackets]: Metasomal segment I in dorsal view shorter and stouter (Fig. 9), about 1.8 times as long as its maximum width [slender, about 2.5 times as long as its maximum width (Fig. 7)]; tergum I with dorsal striae inconspicuous, in consequence of strong and distinct punctures [dorsal striae conspicuous; tergum with nearly no punctures]; mesoscutum strongly punctured, also in areas along notauli [strongly punctured, but areas along notauli with no punctures]; scutellum and metanotum with denser, larger and deeper punctures than those in C. cyanoptera; dorsal face of propodeum with strong Remarks. Cameron (1904: 13) proposed Zethus himalayensis for a single female from "Sikkim [India]" and Bequaert (1928: 157) moved it to the genus Calligaster. Bequaert (1928: 157), having examined the holotype, mentioned that "Although similar to C. cyanopterus, it appears to differ in the shape of the clypeus and is possibly a valid species." Based on the comparison of our specimens from Vietnam [given under "Material examined"] with those of C. cyanoptera from Java and Bali, we recognized that C. himalayensis differs from the latter in having stronger and more distinct punctures.
Other than the locality given in the original description (Sikkim in India), C. himalayensis has been recorded from China (Giordani Soika 1960; without giving any specific localities). We have herein firstly recorded the species from northern parts of Vietnam (new record), suggesting that C. himalayensis may occur along the eastern slope of the Himalayas from Sikkim to northern parts of Vietnam, and probably to southeastern parts of China. Soika, 1960Figs 1, 2, 6, 11 Calligaster viridipennis Giordani Soika, 1960, 74, ♂, "Celebes:
Remarks. Giordani Soika (1960: 72, 74) proposed Calligaster viridipennis for a single male from "Celebes: Enrekang". Since then, no information on this species has been added. Based on the specimens recently collected in Central and Southeast Sulawesi we describe below the female of this Sulawesi-endemic Calligaster wasp for the first time.
The female can be associated with the male by the combination of the following characters: posterior face of propodeum strongly and reticulately punctured; basal fossa of metasomal sternum II deep and distinct, with dense fulvous hairs; wings fuscous, with strong greenish-purple iridescence.
Female characters. Body length (head + mesosoma + metasomal segments I and II) 21-22 mm; fore wing length 20 mm. Head in frontal view subcircular, slightly wider than high, 1.2 times as wide as high (Fig. 2). Clypeus in profile smoothly and weakly convex; in frontal view about 1.5 times as wide as high (Fig. 11), with dorsal margin deeply emarginate medially and ventral margin slightly convex. Mesosoma flattened dorsoventrally, 1.5 times as long as high in lateral view (Fig.  1); in dorsal view 1.4 times as long as wide. Propodeum with posterior face strongly and reticulately punctured (instead of rugosely striated). Metasomal segment I shorter than mesosoma, 0.8 times as long as mesosoma; tergum I strongly convex dorsally (Fig.  1) [moderately convex in cyanoptera]; tergum in dorsal view strongly convex along lateral margins, with faint oblique striae (Fig. 6). Metasomal sternum II with basal fossa as in C. cyanoptera, but distinct and deeper, with dense fulvous hairs.
Body densely covered with dense whitish pubescence; tibia and tarsi with golden pubescence. Head strongly punctured, but vertex and gena only sparsely with smaller punctures. Mesosoma strongly punctured; mesoscutum, scutellum and metanotum with punctures sparser and smaller, as those on vertex and gena. Metasomal segment I with punctures slightly stronger than those on C. cyanoptera; tergum I with punctures smaller than those on mesonotum; tergum II with small and superficial punctures, regularly arranged from base to apex.

Diagnosis.
Calligaster williamsi can be distinguished from its congeners by the combination of the following characters: metasomal tergum I in lateral view barely convex dorsally, with preapical dorsal depression weakly produced (Fig. 4), in dorsal view weakly and evenly convex laterally (Fig. 8); longitudinal striae on tergum I strong, more or less regularly arranged (Fig. 8); apex of male terminal antennal flagellomere rounded [ Fig. 18; bluntly pointed in C. cyanoptera (Fig. 17)