Megalopinus hirashimai Naomi, 1986

Mainda, Tobias, 2024, On Oriental species of the genus Megalopinus Eichelbaum, 1915: one new species and taxonomical and biogeographical notes (Coleoptera, Staphylinidae, Megalopsidiinae), Soil Organisms 96 (1), pp. 37-46 : 38-41

publication ID	https://doi.org/ 10.25674/409
publication LSID	lsid:zoobank.org:pub:30F0C8FF-F793-4C40-B4AD-39BE3847E529
persistent identifier	https://treatment.plazi.org/id/03B42937-FFAC-C815-2BF1-FAB3FEFCFACD
treatment provided by	Felipe
scientific name	Megalopinus hirashimai Naomi, 1986
status

Treatment

Megalopinus hirashimai Naomi, 1986 View in CoL

( Figs 1A–C View Figure 1 , 2A–D View Figure 2 )

Type material studied: male Holotype ‘Japan, Amami-Ôshima Is., Santaro-Tôge, 26.vii.1954, Y. Hirashima’ / red label ‘ HOLOTYPE Megalopinus hirashimai Naomi, 1986 ’ (ELKU). Additional material studied: China: female, ‘China: Hainan Prov., Ledong County, Jianfengling N. R., 1000 m, 18-V-2011, BI Wen-Xuan leg.’ / ‘ Megalopinus hirashimai Naomi , det. Puthz 2012 ’ / ‘coll. Puthz’ (SMNS); ‘ Zhejiang: Tianmushan, 1100m, 19.V.2006, Tang’, only photo of the specimen studied (SNUC). Japan: male, ‘Ie-Rindo’, Okinawa-Is., 22.iv.1986, S. Nomura / yellow label Megalopinus hirashimai Naomi, S. Nomura det. 1996’, aedeagus embedded in Euparal on a transparent platelet [KUM]; female, ‘Nippon: Nanseishotô, Amami-Ôshima, Tatsugô-chô, Nagakumotôge, S V 1996 ’ / white label ‘ Megalopinus hirashimai Naomi, 1986 , det. T. Mainda 2024’ (KUM); male, ‘Tete, Tokunoshima Is., Kagoshima pref. ’ / ‘ 4.v.1988, S. Nomura leg.’ / ‘ Megalopinus hirashimai Naomi , det. V. Puthz 1995’ / ‘coll. Puthz’, aedeagus embedded in Euparal on a transparent platelet (SMNS). Taiwan: male, ‘Chihpenwenchuan, Taitung Taiwan, c. 400m, 6-8.XI.2000, Hiroshi Sugaya leg.’ / ‘ Megalopinus hirashimai Naomi det. Puthz 201 (sic!)’, aedeagus embedded in Euparal on a transparent platelet, termite attached on a separate pointed platelet (KUM); male ‘Tai Tung, Taiwan, H. Sugaya leg, termitophilous’ / ‘ Megalopinus hirashimai Naomi , det. Puthz 2012 ’ / ‘coll. Puthz’, aedeagus embedded in Euparal on a transparent platelet (SMNS); male, ‘Taiwan, Chiayi Co., Alishan, Rd. 129, km 33,5 (env.’ / ‘Chashan, ca. 400 m, for. Litter, 13.IV.2009, S. Vit’ / ‘ Megalopinus hirashimai Naomi , det. Puthz 2012 ’, aedeagus embedded in Euparal on a transparent platelet (MHNG). Thailand: male, ‘W. Thailand: 300m, Thung Yai Wildlife Sanctuary’ / ‘ Tak Province, Umphang District, Mae Chan/MaeKiong confluence. 27.iv.-6.v.1988.’ / ‘Oak/bamboo forest, M.J.D. Brendell, B.M.1988-193.’ / ‘Flight interception trap’ / ‘ Megalopinus sp. , det. 1989 G. de Rougemont’ / ‘ Megalopinus hirashimai Naomi , det. Puthz 2012 ’ / ‘cf. Megalopinus hirashimai Naomi, 1986 , det. Mainda, 2024, internal structure of aedeagus missing!’ (BMNH).

Note: In the description of M. hirashimai the aedeagus was not illustrated ( Naomi 1986). Puthz (2012) thought to have illustrated the aedeagus of this species for the first time, however, not from a type specimen, but using material from Malaysia (Fig. 91: Puthz 2012). Naomi & Nomura (2015) adopted this aedeagus figure, as there seemed to be no doubt about the accuracy.

During the description of two new Megalopinus species from the Philippines in 2022 ( Mainda 2022), I requested Dr. Arnaud Faille from the State Museum of Natural History Stuttgart (coll. Puthz) to send me specimens of M. hirashimai from different countries (e.g., Malaysia, Thailand, Japan, and Taiwan), all previously been identified as M. hirashimai – even if they are very different habitually. Therefore, I requested numerous other specimens of M. hirashimai from different museums, which were available to Puthz (2012, 2013) and identified by him. The following are the results of this study: specimens from Japan, Taiwan, Laos, China (Hainan, Zhejiang), and western Thailand have a clearly different elytral pattern, elytral punctures and aedeagus to the specimens from Malaysia and southern Thailand; the specimens from Laos are also different from the other specimens in their diminutive size and their aedeagus. Thus, there appear to be three different taxa, all of which were previously considered to be M. hirashimai .

To answer the question of which of these three taxa is the ‘true’ M. hirashimai , the holotype had to be examined, which was kindly provided to me along with two other Japanese specimens (see above) by Mr. Toshiharu Mita of Kyushu University, Japan. Examination of the holotype revealed that the ‘true’ M. hirashimai is distributed from Japan across Taiwan to China (Hainan, Zhejiang) and as far south as western Thailand (although this record should be viewed with reservation, as the specimen lacks the internal structure of the aedeagus). The specimens from Laos belong to Megalopinus brancuccii Puthz, 2021 (see below). On the Malay Peninsula, one so far undescribed species occurs ( Megalopinus puthzianus spec. nov.), which is described below.

Puthz (2012) described a new species, Megalopinus nepalensis Puthz, 2012 , and compared it with a species he erroneously misinterpreted as M. hirashimai . In reality, Puthz (2012) compared his M. nepalensis with M. puthzianus spec. nov. In addition, the aedeagus of M. hirashimai is herein figured for the first time, and the species is redescribed. In addition, Fig. 91 in Puthz (2012) and Fig. 2D View Figure 2 in Naomi & Nomura (2015) do not belong to M. hirashimai , but to M. puthzianus spec. nov.

Redescription of the holotype: Measurements: BL: 2.40 mm, DE: 0.51 mm, FBL: 1.63 mm, EL: 0.65 mm, EW: 0.85 mm, HW: 0.90 mm, PL: 0.58 mm, PW: 0.69 mm, SL: 0.55 mm .

Habitus as in Fig. 1A View Figure 1 . Brownish red to orange yellowish (immature specimen), without microsculpture; head chestnut brown; pronotum with light and dark brownish red areas, anterior and posterior margins orange yellowish; elytra light brown with yellowish coloration and three rows of punctures, humeral calli lightened; abdomen yellowish-brown; antennae and legs yellowish.

Head 1.06 times broader than elytra, frons coarsely and very widely punctured, shiny.

Pronotum 1.19 times as broad as long, broadest in anterior third; with four transverse rows of coarse and deep punctures, first (anterior) and second rows disrupted in middle by cluster of irregular punctures, third row disrupted by impunctate Y-shaped area in middle of pronotum, fourth (posterior) row disrupted in middle by cluster of irregular small punctures; punctures always separate; one large puncture in posteriolateral third on both sides. Each side of pronotum with two larger denticles in anterior half and two very small ones in posterior half.

Elytra ( Figs. 1A View Figure 1 , 2A View Figure 2 ) 1.30 times as broad as long; humeral calli prominent. Scutellum with two longitudinal furrows, without punctures; deep, narrow longitudinal impression on both sides of suture. Punctures on left elytron: slr (5), shr (5), dsr (5); punctures on right elytron: slr (5), shr (7), dsr (5). Broadest in middle, posterior and lateral margins convexly rounded.

Abdomen narrower than head, shiny, with distinct paratergites. Basolateral striae of tergite V extends almost to middle of tergite; tergite VII with membranous fringe at posterior margin (metathoric wings fully developed).

Male: Antennomere XI 2.75 times as long and 1.14 times as wide as antennomere X. Sternite VIII shallowly impressed at posterior margin. Tergite VIII without special characters. Sternite IX spatula-shaped. Tergite X very finely microsculptured. Aedeagus slender ( Fig. 1B View Figure 1 ), with two larger, dark sclerotized, pointed sclerites and two more transparent sclerites whose distal blunt ends are each bent over and slightly darkened ( Fig. 1C View Figure 1 ). Parameres with around ten apical setae.

Variation (n = 9): Measurements in mm: BL: 2.38– 2.90 mm, DE: 0.48–0.58 mm, FBL: 1.58–1.80 mm, EL: 0.63–0.75 mm, EW: 0.80–1.00 mm, HW: 0.85–1.00 mm, PL: 0.53–0.63 mm, PW: 0.65–0.80 mm, SL: 0.48–0.73 mm. Punctures on left elytron: slr (2–7), shr (4–9), dsr (4–6); punctures on right elytron: slr (3–5), shr (6–9), dsr (3–9).

Coloration: Brownish-yellow; head darker brown; legs and antennae yellowish; elytra with distinct yellowish coloration (holotype; Tete, Fig. 2B View Figure 2 ; Taiwan, Taitung). Largely blackish; elytra only posteriorly slightly lightened; without lightened cross band in anterior half ( Taiwan, Chiayi; Fig. 2C View Figure 2 ). Blackish ; Elytra with reddish cross band in anterior half and less distinct reddish patches in posterior sutural third ( Hainan ; Fig. 2D View Figure 2 ) .

Female (specimen from Amani): Antennomere XI 1.70 times as long and 1.20 times as wide as antennomere X. Microsculpture on tergite X more distinct.

Comparative notes: Megalopinus hirashimai is related to some smaller species of the M. acutangulus -group (see Puthz 2012 for the group definition) with an impunctate sutural third of elytra, relatively broad head and short lateral striae on tergite V. The species is distinguished from M. nepalensis by the coloration ( Puthz 2012: Fig. 44) and by the longer and more slender internal sclerites of the aedeagus in M. nepalensis ( Puthz 2012: Fig. 92). It is separated from M. brancuccii by the broader shape of the median lobe and the internal structure of the aedeagus in M. brancuccii ( Puthz 2021: Fig. 3 View Figure 3 ) and by longer lateral striae on tergite V.