Revision of the genus Ptomaphagus Hellwig (Coleoptera, Leiodidae, Cholevinae) from Japan

Abstract After examining Japanese material of Ptomaphagus Hellwig from various collections, a new species is described, Ptomaphagus (s. str.) piccoloi sp. n., and a new subjective synonym proposed, Ptomaphagus (s. str.) kuntzeni Sokolowski, 1957 = Ptomaphagus (s. str.) amamianus Nakane, 1963, syn. n., in this paper. Relevant morphological characters of examined species of Ptomaphagus are illustrated with colour plates, and known distributions are mapped.

In the fauna of Japan, only three species in the subgenus Ptomaphagus s. str. had been recorded before this study, namely P. (s. str.) sibiricus Jeannel, 1934, P. (s. str.) kuntzeni Sokolowski, 1957 and P. (s. str.) amamianus  However, when we examined specimens previously identified as Ptomaphagus (s. str.) kuntzeni and P. (s. str.) amamianus from various collections, we found there are no differences at the specific level between them. After examining both holotypes, a new subjective synonym is proposed: P. (s. str.) kuntzeni Sokolowski, 1957 = P. (s. str.) amamianus Nakane, 1963, syn. n. Moreover, examined specimens previously identified as P. (s. str.) sibiricus from Japan are conspicuously different to the holotype of P. (s. str.) sibiricus which was described from Vladivostok, Russia (Jeannel 1934). Therefore, a new species from Japan is described and illustrated here: P. (s. str.) piccoloi sp. n. The dubious occurrences of P. (s. str.) kuntzeni in Myanmar and P. (s. str.) sibiricus in Japan, as well as several new island records, and the bionomics of the two species are briefly discussed in this paper. Relevant morphological characters of examined species of Ptomaphagus are illustrated with colour plates, and known distributions are mapped.

Material and methods
Specimens were relaxed and softened in a hot saturated solution of potassium hydroxide for 4 minutes (for mounted dry specimens) or 8 minutes (for alcohol-preserved specimens), and then transferred to distilled water to rinse the residual potassium hydroxide off and stop any further bleaching. The softened specimens were moved into glycerin and dissected there to observe morphological details. After examination, the body parts were mounted on a glass slip with Euparal Mounting Medium for future studies. Habitus photographs were taken using a Canon macro photo lens MP-E 65mm on a Canon 550D. Observations, photographs and measurements of morphological details were performed using an Axio Zoom.V16 motorized stereo zoom microscope with an AxioCam MRc 5 in Beijing, or an Olympus BX53 microscope with an Olympus DP73 in Prague. The final deep focus images were created with Helicon Focus 5.3 stacking software in Beijing or Zerene Stacker 1.04 in Prague. The program Adobe Photoshop CS6 was used for post processing. Exact label data are cited for all specimens examined. Authors' remarks and addenda are placed in square brackets, separate label lines are indicated by a slash (/) and separate labels by a double slash (//). Measurements are mean values based on 5 specimens.
The material examined for this study is deposited in the following collections and museums:  Pronotum (Fig. 3B) transverse, widest just before hind angles, PW/PL = 1.5. Sides gently arched, gradually narrowing from posterior to anterior; hind angles drawn out, acute and sharp. Posterior margin widely protruding in the middle part, distinctly emarginate near hind angles.
Prolegs robust, with basal three protarsomeres (Fig. 3C)   opening of genital orifice situated on dorsal surface, deeply cut inwards on left edge of median lobe at subapex. Ventral surface of the apex of the median lobe (Fig. 4B, D) inserted with 5 ventrally oriented setae on the left side and 4 ventrally oriented setae on the right side; parameres narrow, reaching almost to apical 1/5 of median lobe, each apex (Fig. 4E) with 2 lateral setae and 1 apical seta relatively shorter. In lateral view (Fig. 2B, E), median lobe distinctly thick, regularly bent ventrad and gradually tapering towards a subround apex. Endophallus with stylus quite slender, a cheliform complex below the base of stylus, and a circular complex at the basal region. Female. Similar to male in general appearance (Fig. 1C), including elytral apices (Fig. 3H), but distinguished by the following characteristics: protarsi (Fig. 3D)  Distribution. China (Taiwan), Japan (Fig. 8), ?Myanmar.
It should be noticed that Szymczakowski (1964) described a single female specimen from Kambaiti, Myanmar (coll. Naturhistoriska Riksmuseet, Stockholm) as Ptomaphagus (s. str.) kuntzeni. We concur with the opinion of Nishikawa (2011) that the occurrence of P. (s. str.) kuntzeni in Myanmar is dubious because of the wide geographical gap and the discrepancies of the morphological description of Szymczakowski (1964) with specimens from Japan.
According to the present data, this species is one of the most widespread cholevines in Japan, known from Honshu, Shikoku, Kyushu and Ryukyus. However, we have not yet examined any specimens from the northernmost area of Honshu (above the 38 th parallel) or from the southern Kume-jima Island in Ryukyus (Fig. 8). The species is recorded herein from Sadoga-shima Island, Shimokoshiki-jima Island and Kume-jima Island for the first time. Incidentally, no Ptomaphagus species have been recorded from Hokkaido to date. Moreover, Perreau (1996) reported the species from Taiwan Island under the name P. (s. str.) amamianus. We will deal with this area in a next paper devoted to Ptomaphagus from Taiwan.
Collecting methods for the material examined mostly indicate a necrophagous association, such as traps baited with decaying animal matter.  apical parts of meso-and metatarsi more or less paler. Dorsum continuously clothed with fine, recumbent, yellowish pubescence. Insertions of pubescence on dorsal surfaces of pronotum, elytra and femora aligned along transverse striolations; interspace between two striolations glabrous.
Head transverse, HW/HL = 1.5. Clypeofrontal suture absent. Clypeus with anterior margin slightly rounded. Compound eyes small, EW/HW = 0.1. Antennae (Fig.  5A) slender, AL/HW = 1.1; antennomere III a little shorter than II; VI with length/ width = 0.5; XI pear-shaped.  a long history of studies, it has not yet been recorded from Shikoku; also we have not examined any specimens of this new species from northern Honshu, above the 37 th parallel (Fig. 9). In these two areas, the new species can be regarded as at least rare or more probably completely absent. Specimens from Yashiro-jima Island in the Setonaikai Inland Sea were previously reported (as P. sibiricus) in Tanaka and Ban (2006).
As indicated in the material examined, P. (s. str.) piccoloi sp. n. has been collected from various habitats such as caves, under stones at the base of debris slopes and in litter layers.
Collecting methods for the material mostly indicate a necrophagous association, such as traps baited with decaying animal matter.