Taxonomic revision of the genus Callimerus Gorham s. l. (Coleoptera, Cleridae). Part I. latifrons species-group

Abstract The latifrons species-group (=Brachycallimerus sensu Chapin 1924, Corporaal 1950; = flavofasciatus-group sensu Kolibáč 1998) of Callimerus Gorham is redefined and revised. Five species are recognized including one new species Callimerus cacuminis Yang & Yang sp. n. (type locality: Yunnan, China). Callimerus flavofasciatus Schenkling, 1902 is newly synonymized with Callimerus latifrons Gorham, 1876. Callimerus trifasciatus Schenkling, 1899a is transferred to the genus Corynommadius Schenkling, 1899a. Callimerus gorhami Corporaal, 1949 and Callimerus pallidus Gorham, 1892 are excluded from the latifrons species-group (their assignment to a species-group will be dealt with in a subsequent paper). A key to species of the latifrons species-group is given and habitus of each type specimen, male terminalia, and other diagnostic characters are illustrated.

In the present paper, we follow the classification system of Kolibáč (1998) and treat Brachycallimerus Chapin in a species-group rank, named it latifrons species-group (= flavofasciatus-group sensu Kolibáč 1998); the name of the species group is changed because C. flavofasciatus Schenkling, 1902 is synonymized with C. latifrons Gorham, 1876 herein, which is the oldest species of this species group.The purpose of this paper is to redefine latifrons species-group and revise its members.Five species are kept in the redefined latifrons species-group, with one new species from China (Yunnan) and Laos; one new synonym is proposed and three species that formally belong to this species group are excluded.The exclusion of Callimerus doesburgi (Corporaal, 1937) by Kolibáč (1998) is approved.All members of this species group are distributed in Southeast Asia.Whole male abdomens were removed from the body with fine forceps and treated with 10% KOH solution at room temperature for 8-12 hours.Male terminalia were prised apart, rinsed and examined in 70% ethanol.Tegmina were photographed when totally dry in the air, while other parts of male terminalia were photographed in glycerol.All male terminalia components were permanently stored within glycerol in genital vial which was pinned below specimen.Habitus images were captured using a Nikon D7000 digital camera with Tamron SP 90mm lens, or Canon 450D digital camera with Canon Macro 100 mm lens.Terminalia images were captured by a Nikon digital Sight DS-SM camera fitted to a Nikon SMZ-1500 stereoscopic dissecting microscope controlled by ACT-2U software, or by a Canon 450D digital camera fitted to a Nikon SMZ-1500 stereoscopic dissecting microscope.Series of partially focused photographs were taken and then combined using Helicon Focus software, and finally processed with Adobe Photoshop software.Line drawings were made under Leica MZ125 stereoscopic dissecting microscope or created from color photographs using Adobe Illustrator software.Distribution maps, created in Adobe Illustrator software, are based on examined materials and published records.

Materials
Measurements were made under a stereomicroscope using an ocular micrometer.Body length is the linear distance from labrum to elytral apices.Body width is the maximum width across elytra.Abbreviations are shown in the text as follows: AL: antennal length; AD: distance between two antennae insertions.EyD: minimum distance between two eyes; EyW: maximum eye width in dorsal view (Fig. 71); PL: prothorax maximum length; PW: prothorax maximum width; EL: elytra maximum length; EW: elytra maximum width.Terminology mostly follows Ekis (1977).The male tegmen possesses three membranous semi-transparent regions, a pair of slit-like ones situated at both dorsal-lateral sides (66)(67) and the other, more or less cordiform, situated ventrally (67)(68)(69); these membranous regions are more clear to see when tegmen is dry.The ventral membranous region is cordiform, surrounded by a pair of outer margins and a pair of inner margins (Figs 68,69).Spicular forks are comprised of a spicular apodeme (sensu Opitz 2010) and a pair of spicular arms (Fig. 63; = lateral plates of the spicular fork sensu Opitz 2010).When describing male termi-nalia, the following abbreviations are introduced: TML: length of ventral membranous region of the tegmen; TMW: width of ventral membranous region of the tegmen (Figs 61,(68)(69); TMaL: vertical length of apical lobe of the ventral membranous region of tegmen; SApL: length of spicular apodeme; SFL: length of spicular fork.
Original and later important taxonomic references are cited after taxon names.Full label data are provided for name-bearing type specimens: label data of each specimen are enclosed within a pair of double quotation marks, and individual labels are separated by a slash.All writings are cited in their original spelling, punctuation and language.Original italic or capital is ignored.Notes and elaborations relating to label data are enclosed in square brackets (including the writer, translation, etc).Red labels have been added to holotypes, paratypes, lectotypes and paralecto-types.Full label data or, in most cases, only locality data are provided for other specimens.When transcribing the label data, "hw." is short for "handwritten", and ellipsis are used if the original writing were illegible and unable to be transcribed.Authors of the handwriting on determination labels are identified with the clues given by Horn et al. (1990) and/ or confirmed by present curators of correlative museums where the authors of those handwritings worked.Specimens marked with an asterisk are those whose male terminalia are figured in this paper.
It differs from coomani-group (sensu Kolibáč 1998) by claws with a basal tooth (Fig. 57) and metatibiae with a subapical projection on the outer edge (Fig. 58).
In the integumental coloration (yellow and black), C. pallidus Gorham, 1892 (Carin Hills, Chebà;Figs 79) , C. gorhami Corporaal, 1949 (Sumatra's East Coast;Fig. 81), C. nigroapicalis Pic, 1955 (Fujian;Fig. 84, 85), C. terminalis Chapin, 1919 (Sandakan, North Borneo;Fig. 86, 87), and some species related to C. insolatus Pascoe, 1860 might be similar to members of the latifrons species-group.The differences between C. pallidus, C. gorhami and this species group are provided in the text below.C. nigroapicalis is different from this species group in pronotum longer than wide.C. terminalis is different from this species group in claws without a basal tooth, subapical projection on outer edge of metatibia rudimental, pronotum longer than wide.Species related to C. insolatus differ from this species group in claws without a basal tooth.
Distribution.Southeast Asia (Fig. 72).Discussion.This species group is probably advanced groups within Callimerus s. l., as Kolibáč (1998) suggested; but its sister group cannot be determined with certainty until the intra-taxonomy of the dulcis species-group (sensu Kolibáč 1998) has been resolved, which nearly contains two-thirds of species of this genus.
Note on Type material.The name-bearing types of latifrons and flavofasciatus were not fixed in the original publications, so lectotypes of both species are designated here to express the taxonomic purpose of fixing the name to a single specimen and preventing further uncertainty regarding the taxon to which the names are applied.Only one specimen of each species was found in related museums.
Comment on synonymy.Gorham (1876: 67) described C. latifrons from Philippines as "Nigro-piceus, …, elytrorum fasciâ basali, maculâque pone medium reniformi pallide testaceis" (with "a basal fascia (widest in centre) and two kidney-shaped spots, almost touching suture, yellow").Schenkling (1902: 320) published C. flavofasciatus from Thailand, and stated that it differed from C. latifrons by having an additional yellow spot at apex of elytron.Chapin (1924: 190) synonymized C. flavofasciatus with C. latifrons and argued, C. latifrons having such a yellow spot at apex of elytron because all the Philippines specimens he examined having that (he also stated such a spot was mentioned in Gorham's original description, which is not true though).Corporaal (1939: 193) found a specimen from Laos lacking a yellow spot at apex of elytron, which agrees well with Gorham's description; so he regarded the specimen as a representative of the typical form of C. latifrons, and treated flavofasciatus as a variety of C. latifrons for having an additional yellow spot at elytral apex.Corporaal (1948: 287) re-treated C. flavofasciatus as a distinct species for presence of such a spot.However, after we located it from MNHN, we found that the type of C. latifrons actually having a yellow spot at apex of elytron, which was simply not mentioned in the original description.We compared the external morphology and male genital characters of type specimens of C. latifrons and C. flavofasciatus and found no significant differences; therefore, we synonymize C. flavofasciatus with C. latifrons.In addition, the specimen from Laos mentioned in Corporaal (1939: 193;1948: 287) lacking the additional yellow spot is conspecific with C. latifrons; it is only the color variation of this species, as posterior black bands of elytra reach to the extreme apex and thus the apical yellow spot missing.
Diagnosis.C. latifrons can be rapidly distinguished from other species of this species group by its entirely black pronotum (Figs 1, 2).
There are 3 other species of this species group with two black spots on each elytron: C. latesignatus, C. pectoralis and C. rusticus.In addition to the difference in pronotal coloration, C. latifrons can be differentiated from these three species by: (1) EL/EW about 2.2 (in other 3 species 1.7-1.8);(2) anterior black spot of elytron spanning from elytral outer margin to suture, thus forming a complete black band across elytra (Fig. 1); (3) apices of paramere divergent (Fig. 7-9).
Variation.The posterior black spot on elytron in most cases doesn't reach to the extreme apex and thus a small region of elytron extreme apex is yellow.But in a few specimens the black spot reach to the extreme apex, so the yellow portion is missing.These two color forms could be found in the same locality (Yunnan, China for instance) and they are not correlated with sex.Note on Type material.The name-bearing type of C. latesignatus was not fixed in the original publication so the lectotype is designated here to express the taxonomic purpose of fixing the name to a single specimen and preventing further uncertainty regard- ing the taxon to which the name is applied.The specimen deposited in MCSN is chosen as the lectotype because the type series were originally from that museum's expedition.
Variation.The pronotum of most specimens is yellow with a small transverse black patch on anterior margin, but two females examined don't have such a patch and thus the pronotum is totally yellow (one of which is the paralectotype in MNHN).
Note on Type material.The lectotype is one of the specimens sent to S. Schenkling for study from MCSN, with a label "quadripunctatus Schklg" handwritten by R. Gestro, the former curator of MCSN.The name "quadripunctatus Schklg" has never been published, however, the locality and morphological characters of this specimen perfectly accord with the original publication of C. pectoralis.On the other hand, a specimen found in Coll.M. Pic from MNHN (locality Medan, Sumatra) determined as C. pectoralis by Schenkling himself is conspecific with the specimen labeled "quadripunctatus Schklg" .In this case, it is assumed that "quadripunctatus" was the first name that came to Schenkling's mind and written down in the identification list that sent to MCSN, but later Schenkling changed his mind and published the species with another name "pectoralis".Regardless of the details, the specimen found in MCSN undoubtedly belongs to the type series and we therefore designated it as the lectotype of Callimerus pectoralis Schenkling here for the taxonomic purpose of fixing the name to a single specimen and preventing further uncertainty regarding the taxon to which the name is applied.
The difference between this species and C. latesignatus is provided in the diagnosis section under C. latesignatus.

Callimerus rusticus
Note on Type material.The original description of Callimerus rusticus Gorham mentioned two specimens, but the name-bearing type was not fixed.We found both syntypes in MNHN and RMNH respectively, and designate the male from Coll.Gorham in MNHN as lectotype here to express the taxonomic purpose of fixing the name to a single specimen and preventing further uncertainty regarding the taxon to which the name is applied.
The original publication of Lemidia bipunctatus Kuwert noted that only one specimen was examined, so the holotype was originally fixed by monotypy.
Diagnosis.This species can be rapidly distinguished from other species of the latifrons species-group by posterior spot on elytron being located lateral-apically, barshaped, with a length to width ratio of about 4:1 (Fig. 41).
This species is most similar to C. pectoralis; the difference between them is provided in the diagnosis section under C. pectoralis.
Distribution (Fig. 72).Indonesia (Sulawesi).Diagnosis.The new species can be rapidly distinguished from other species of the latifrons species-group by: elytron with only one black spot at apex, lacking anterior spot; metasternum and metepisternum yellow; apices of parameres sharply attenuate, then divergent.

Callimerus cacuminis
The coloration of this new species is similar to that of Callimerus pallidus Gorham and Callimerus gorhami Corporaal, which are excluded from the latifrons species-group in the present paper.The new species, however, differs from C. pallidus by EL/EW 2.27-2.34,PL/PW about 0.9, EyD/EyW about 1.1 (Fig. 54) (EL/EW about 3.1, PL/ PW about 1.2, EyD/EyW about 1.9 in C. pallidus; Fig. 79).
Variation.In the holotype and a paratype (No.IOZ(E)1126332), the black spot on elytron reach to the extreme apex; in the other paratypes, the black spot does not reach to the extreme apex so that a tiny region in extreme apex is yellow.
Distribution (Fig. 72).China (Yunnan), Laos.Etymology.The Latin adjective "cacuminis" means of a peak, top or tip, and emphasizes the singular black spot on elytra apex.
Note on Type material.The name-bearing type of trifasciatus was not fixed in the original publication.We designate the only specimen found in MCSN as lectotype to express the taxonomic purpose of fixing the name to a single specimen and preventing further uncertainty regarding the taxon to which the name is applied [The red lectotype label will be sent to MCSN after this paper published].

Callimerus doesburgi
Note on Type material.The sex of the paratype was mistaken in the original publication.
Taxonomic position.This species was included in Kolibáč's (1998) "coomanigroup" for its claws without a basal tooth; moreover, its metatibia without subapical projection on outer edge and body with metallic luster, are evidence in support of Kolibáč's assignment.Note on Type material.The original publication of C. pallidus noted that only one specimen was examined, so the holotype was fixed in the original publication by monotypy.

Callimerus pallidus
Taxonomic position.Although this species has a basal tooth on claw, and we didn't examine its character of metatibia subapical projection (the only examined specimen is glued on board with metatibia not viewable), we are still confident to exclude it from the latifrons species-group for the following character states: PL/PW >1 (ratio 1.2), EyD evidently larger than EyW (ratio 1.9).Its nearest relative within the large genus Callimerus is still unclear.Note on Type material.The original publication of C. gorhami noted that only one specimen was examined, so the holotype was fixed in the original publication by monotypy.

Callimerus gorhami
Taxonomic position.This species has a basal tooth on claw and metatibia with subapical projection on outer Although it accords with the latifrons species-group in these two important characters, our exclusion of it from this species-group is based on the following characters: PL/PW >1 (ratio 1.1); EyD evidently larger than EyW (ratio 2.4); elytra apex with scales.Its nearest relative is still unclear.

Discussion
Within these five species of the latifrons species-group, C. latesignatus, C. pectoralis and C. rusticus seem to be most closely related.This assumption is supported by the apices of paramere convergent and EL/EW less than 2 (ratio 1.7-1.8);moreover, they have similar arrangement of elytral spots, with only different degrees of spots size and black pigmenting on ventral side.Furthermore, C. pectoralis and C. rusticus could be closest to each other, because of their similarly shaped parameres and male sternite VIII.The distribution of C. pectoralis and C. rusticus shows a substitute pattern (Fig. 72), whereas C. latesignatus is distributed to their northern border, and sympatric with C. pectoralis in Yunnan, China.
examined in the present paper are deposited in the following collections.Abbreviations are shown in the text as follows: CAU China Agricultural University, Beijing, China CCCC Collection of Mr. CHEN Changchin, Taiwan, China IZAS Institute of Zoology, Chinese Academy of Sciences, Beijing, China MCSN Museo Civico di Storia Naturale, Genova, Italy MNHN Muséum National d'Histoire Naturelle, Paris, France NHMB Naturhistorisches Museum, Basel, Switzerland NHML The Natural History Museum, London, United Kingdom NHRS Naturhistoriska Riksmuseet, Stockholm, Sweden OUM Hope Department of Entomology, University Museum, Oxford, United Kingdom RMNH Rijksmuseum van Natuurlijke Historie, Leiden, The Netherlands USNM National Museum of Natural History, Smithsonian Institution, Washington, D. C., USA ZMAN Zoölogisch Museum Amsterdam, Leiden, The Netherlands