New polymorphic species of the genus Menimus Sharp, 1876 (Diaperinae Latreille, 1802, Gnathidiini Gebien, 1921, Gnathidiina Gebien, 1921) from Borneo and Sumatra are described: M. burut sp. n., M. crockeri sp. n., M. dasun sp. n., M. dayak sp. n., M. grimmi sp. n., M. jacobsoni sp. n., M. kadazan sp. n., M. kinabalucus sp. n., M. loebli sp. n., M. matangicus sp. n., M. merkli sp. n., M. punggulicus sp. n., M. sabahicus sp. n., M. sarawakicus sp. n. A new synonym is proposed: Menimus seriepunctatus Gebien, 1927 (Menimus malayicus Schawaller, 2016 syn. n.). A lectotype is designated for Menimus seriepunctatus Gebien, 1927. Menimus burut sp. n. and Menimus sabahicus sp. n. are the first known species with 9-segmented antennae, whereas Menimus matangicus sp. n. completely lacks eyes. An identification key is compiled for all 16 species so far known from Borneo and Sumatra. The high morphological plasticity of the epigean species of Menimus should be re-examined in a more comprehensive study of all Gnathidiini, not only with morphological but also with molecular data.
Introduction
The tenebrionid genus Menimus Sharp, 1876 (Diaperinae Latreille, 1802, Gnathidiini Gebien, 1921) contains so far about 80 morphologically very diverse species. The species are distributed in the Oriental, Papuan, Australian, and Pacific Regions with a few species reaching the southern areas of the Palaearctic Region in Japan (Lewis 1894), Sikkim (Kaszab 1982), Yunnan (Medvedev 2007; Schawaller 2009), India and northern Burma (Schawaller 2016a), and Taiwan (Ando 2018). Medvedev (2007) compiled a list of all described species with full references. At the same time, he synonymised Neomenimus Kaszab, 1939 and discussed the taxonomic significance of some particular morphological features. Recently, nine species from Peninsular Malaysia and adjacent southern Thailand were described by Schawaller (2016b), and three species were described from Sulawesi (Schawaller & Ando 2018). From Borneo and Sumatra, only three species of Menimus had been described so far (Gebien 1927; PIC 1930; Bremer 1997). However, one of them is a junior synonym (see below). Newly collected specimens are presented herein, which increase the total number of species from both large and zoogeographically similar Sunda islands to 16.
The tribe Gnathidiini Gebien, 1921 is divided in two subtribes: Anopidiina Jeannel & Paulian, 1945 and Gnathidiina Gebien, 1921. The latter is characterised by an unexposed clypeal membrane and contains, among others, the herein treated genus Menimus. Anopidiina from Africa with an exposed clypeal membrane were recently listed by Schawaller & Purchart (2012), and a new speciose genus of this subtribe from the West Indies was described by Spiessberger & Ivie (2020).
The newly collected species of Menimus described herein show a high plasticity of morphological features. Very probably, the so far described species of the genus from a large geographical area do not represent a monophyletic unit and must be distributed to different genera. In other words, the synonymisation of different genera by KASZAB (1982) and Medvedev (2007), or the creation of subgenera based on single characters (for example the subgenus Sinomenimus Medvedev, 2007) should be reexamined in a more comprehensive study of all Gnathidiini, not only with morphological but also with molecular characters. Therefore, the species described herein are not assigned to subgenera because of their uncertain taxonomic status.
Already Gebien (1925) recognised the diversity among species of Menimus (translation from German: “If I would use the form of the antennae and of the epistome for the creation of new genera, we would obtain a high number of genera with only few species each”). Gebien expected the discovery of several new species and planned to later split Menimus into several genera.
Good examples of surprising discoveries within this tribe are the recent description of the genus Sakaiomeni-mus Ando, 2003 from Japan, which has 11-segmented antennae (Ando 2003), and the present description of two species with 9-segmented antennae—with all other taxa of Gnathidiini characterised by 10-segmented antennae (besides other characters). Another surprise is the discovery of a species on Borneo completely lacking eyes (M. matangicus sp. n.). The subgenus Sinomenimus was based on a blind species from China, but this large species is completely different in external characters from the newly-discovered blind and tiny species from Borneo. Possibly, also Micropeneta Pic, 1921, with modified male head (see Bremer 1997; Li & Jiang 2019), is a synonym of Menimus.
The species of Menimus have an epigean way of life in mature forests, and can be collected mostly by sifting or with Berlese/Winkler extractors. Andújar & Grebennikov (2021) used a special technique for collecting these beetles, including species of Gnathidiini, on Madagascar. Nearly all the species examined herein, with the exception of M. jacobsoni n. sp., possess wings. Nevertheless, they probably have limited flight abilities, because they obviously occur only in small areas. It seems likely that most species evolved in their present area and that they did not immigrate from mainland Asia or other Sunda islands to Borneo or Sumatra.
So far, nine species of Menimus are known from Peninsular Malaysia, three from Sumatra, and 14 from Borneo. This discrepancy between both Sunda Islands might be caused by different collecting activities. Only one species, M. lineatopunctatus (Pic, 1930), was collected in Peninsular Malaysia, Borneo, and Sumatra, and only one species (M. seriepunctatus Gebien, 1927) was collected in Peninsular Malaysia and Sumatra, all other species seem to be endemic either to Sumatra or Borneo.
Material and methods
The locality data are not given verbatim, but are modified in a standard form, partly completed by additional geographical information for the better localisation, and are translated into English when given in other languages on the labels. The designated holotypes and paratypes are provided with printed red labels. The aedeagi are mounted by a water-soluble glue on cards together with the specimens. The photographs were taken with a VHX-5000 Keyence microscope, and edited and assembled in Adobe Photoshop Elements 15.
In some species, only female(s) were available, thus the aedeagus remains unknown. In a few other species the sex of the corresponding holotypes was not examined. Because of their tiny size (1–2 mm) and the presence of only single and rare specimens, the risk of destruction of these few available specimens seemed too high to take. Moreover, all treated species can be distinctly recognised without knowledge of the aedeagal shape (see identification key).
Acronyms of depositories
NHMUK
Natural History Museum, London, United Kingdom
CKA
Collection of Dr. Kiyoshi Ando, Osaka, Japan
CRG
Collection of Dr. Roland Grimm, Neuenbürg, Germany
MHNG
Muséum d'Histoire Naturelle, Geneva, Switzerland
NHMB
Naturhistorisches Museum, Basel, Switzerland
SMNS
Staatliches Museum für Naturkunde Stuttgart, Germany
ZSM
Zoologische Staatssammlung, Munich, Germany
The species of Menimus from Borneo and Sumatra
Menimus burut sp. n.
(Fig. 13)
Type material
Holotype (sex not examined): Borneo, Sarawak, confluence of Sun Oyan and Mujong rivers, E Kapit, 50 m, 19.V.1994, leg. I. Löbl & D. Burckhardt, MHNG.
Description
Body length 2.1 mm, body shape elongated parallel. Dorsal side brown without colour pattern or metallic shine, surface shiny and without distinct setation, antennae and legs lighter brown. Head with small punctation, sparser on clypeus. Clypeal membrane not exposed. Eyes small and slightly globose. Antennae (Fig. 13) 9-seg-mented with separated 3-segmented club. Pronotum widest behind middle, 1.5x as wide as long, anterior corners rounded and not protruding, posterior corners rectangular, lateral margins rounded, with fine dentation, basal margin finely bordered; surface shiny with punctation similar to that on head, disc convex without any impressions; prothoracic hypomera with scattered punctation as on pronotum, surface smooth and shiny; prosternal apophysis conical, pointing posteriorly. Elytra elongated parallel, 0.6x as wide as long, widest at middle, elytra with irregular punctation, only rarely arranged in indistinct rows, punctures feebly larger than pronotal punctures; lateral margins with fine dentation and visible in dorsal view only in the anterior third of the elytra, humeral angles pronounced; epipleura diminishing somewhat before apex, without distinct punctures. Wings present. Abdominal ventrites with punctation as large as on elytra, last visible ventrite 5 unbordered and without modifications. Legs without specific characters, tibiae rounded in cross section and exteriorly without any keels. Aedeagus unknown (sex not examined).
Diagnosis
Menimus burut sp. n. shares the 9-segmented antennae with a 3-segmented club with M. sabahicus sp. n., but in M. sabahicus sp. n. the pronotum is more convex, the elytra are broader and the elytral punctation is arranged in rows. Additionally, the eyes are larger and slightly globose in M. burut sp. n., whereas in M. sabahicus sp. n. the eyes are smaller and nearly flat. See also under M. kadazan sp. n. (with 10-segmented antennae). For separation of the other species from Borneo and Sumatra, see key.
Etymology
Named in honour of the human ethnic group Burut, from Borneo.
Figs. 1–4.
Dorsal view of species of Menimus from Borneo and Sumatra. – 1. M. grimmi sp. n., paratype, SMNS. 2. M. merkli sp. n., paratype, SMNS. 3. M. crockeri sp. n., paratype, SMNS. 4. M. seriepunctatus Gebien, 1927, non-type, Sumatra, SMNS. Scale bar: 1 mm.
Menimus crockeri sp. n.
(Figs. 3, 17)
Type material
Holotype (♂): Borneo, Sabah, Crocker Range, Gunung Emas, 500–1900 m, 6–21.III.1995, leg. I. Jeniš, SMNS.
Paratypes: Borneo, Sabah, Crocker Range, Gunung Alab, 1700 m, 23–29.V.1998, leg. J. Kodada & F. Ciampor, 3 ♀♀, SMNS.
Description
Body length 3.0–3.4 mm, body shape elongated parallel. Dorsal side dark brown, without colour pattern or metallic shine, surface shiny and without distinct setation, antennae and legs lighter brown. Head with small punctation, sparser on clypeus. Clypeal membrane not exposed. Eyes small, globose. Antennae (Fig. 3) 10-segmented with separated 3-segmented club. Pronotum widest at middle, 1.5x as wide as long, anterior corners rounded and not protruding, posterior corners rectangular, lateral margins rounded, with fine dentation, basal margin with indistinct border; surface shiny with punctation similar to that on head, disc convex without any impressions but with a distinct transverse row of punctures before base; prothoracic hypomera with scattered punctation as on pronotum, surface feebly wrinkled and shagreened; prosternal apophysis conical, pointing posteriorly. Elytra parallel elongated, 0.7x as wide as long, widest at middle, with punctation irregularly arranged in rows, punctures distinctly larger than pronotal punctures; lateral margins with fine dentation and visible in dorsal view nearly over the complete length of the elytra, humeral angles pronounced; epipleura diminishing somewhat before apex, with a row of distinct punctures smaller than those on metasternum. Wings present. Abdominal ventrites with punctation as large as on elytra, last visible ventrite 5 unbordered and without modifications. Legs without specific characters, tibiae rounded in cross section and exteriorly without any keels. Aedeagus (Fig. 17) with apicale short and broad, spade-like, basale feebly bent in lateral view.
Diagnosis
Menimus crockeri sp. n. can be recognised by the large and elongated parallel body, the 3-segmented antennal club, the rounded lateral margins of the pronotum, the rough elytral punctation, and the shape of the aedeagus. For separation from the other species from Borneo and Sumatra, see key.
Etymology
The type series was collected in the Crocker Range, which was named in honour of William Maunder Crocker (1843–1899), a British administrator in Borneo.
Menimus dasun sp. n.
(Figs. 15, 18)
Type material
Holotype (♂): Borneo, Sabah, Crocker Range, Gunung Alab, 1700 m, 23–29.V.1998, leg. J. Kodada & F. Ciampor, SMNS.
Paratypes: Same data as for holotype, 13 ex., SMNS. – Borneo, Sabah, Crocker Range, Gunung Emas, 1500–1700 m, 6–18.VI.1996, [collector unknown], 1 ex., SMNS. – Borneo, Sabah, Crocker Range, 1550–1650 m, 16.V.1987, leg. I. Löbl & D. Burckhardt, 1 ex., MHNG. – Borneo, Sabah, Mt. Kinabalu NP, Headquarter, 1560–1660 m, 24.IV.1987, leg. A. Smetana, 1 ex., MHNG. – Borneo, Sabah, Mt. Kinabalu NP, Headquarter, 1520 m, 11.VIII.1988, leg. A. Smetana, 1 ex., MHNG.
Description
Body length 2.4–2.8 mm, body shape round. Dorsal side brown without colour pattern or metallic shine, surface shiny and without distinct setation, antennae and legs light brown. Head with rough and confluent punctation, sparser on clypeus, surface of head wrinkled. Clypeal membrane not exposed. Eyes small, globose. Antennae (Fig. 15) 10-segmented with separated 3-segmented club. Pronotum widest at base, 2.3x as wide as long, anterior corners rounded and not protruding, posterior corners rectangular, lateral margins parallel-sided in basal half, with indistinct dentation, basal margin with indistinct border; surface shiny, wrinkled, with rough and confluent punctation as on head, disc convex without any impressions; prothoracic hypomera not punctured, with surface smooth and shiny; prosternal apophysis not distinctly pointing posteriorly. Elytra round circular, 0.95x as wide as long, widest at middle, with completely irregular punctation, punctures rough and confluent like pronotal punctures, surface wrinkled; lateral margins with fine dentation and visible in dorsal view only at shoulders, humeral angles pronounced; epipleura diminishing somewhat before apex, surface wrinkled as on elytra. Wings present. Abdominal ventrites with rough punctation as large as on elytra, last visible ventrite 5 unbordered and without modifications. Legs without specific characters, tibiae rounded in cross section and exteriorly without any keels. Aedeagus (Fig. 18) with apicale short and broad, nearly pentagonal with rounded apex, basale feebly bent in lateral view.
Diagnosis
Menimus dasun sp. n. can be recognised by the small body size, by the round body, the 3-segmented antennal club, and particularly by the rough and confluent dorsal punctation without any elytral rows. This dorsal structure is so far unique among the Oriental congeners. M. dayak sp. n. is also small and round, with a 3-segmented antennal club and with irregular dorsal punctation, but this punctation is finer and the surface of the elytra is smooth. Additionally, in M. dasun sp. n. the eyes are somewhat larger and more globose, as in M. dayak sp. n. For separation from the other species from Borneo and Sumatra, see key.
Etymology
Named in honour of the human ethnic group Dasun, from Borneo.
Figs. 5–9.
Dorsal view of species of Menimus from Borneo and Sumatra. – 5. M. kinabalucus sp. n., paratype, CRG. 6. M. sarawakicus sp. n., paratype, SMNS. 7. M. matangicus sp. n., holotype, MHNG. 8. M. loebli sp. n., paratype, SMNS. 9. M. punggulicus sp. n., paratype, SMNS. Scale bar: 1 mm.
Menimus dayak sp. n.
(Fig. 16)
Type material
Holotype (sex not examined): Borneo, Sarawak, Gunung Penrissen, 1000 m, 23.V.1994, leg. I. Löbl & D. Burckhardt, MHNG.
Paratypes: Same data as for holotype, 12 ex. MHNG, 4 ex. SMNS.
Description
Body length 1.3–1.5 mm, body shape round. Dorsal side brown without colour pattern or metallic shine, surface shiny and without distinct setation, antennae and legs light brown. Head with fine punctation, sparser on clypeus. Clypeal membrane not exposed. Eyes small, slightly globose. Antennae (Fig. 16) 10-segmented with separated 3-segmented club. Pronotum widest at base, 2.0x as wide as long, anterior corners rounded and not protruding, posterior corners rectangular, lateral margins parallel-sided in basal half, without dentation, basal margin unbordered; surface shiny with distinctly finer punctation than on head, disc convex without any impressions; prothoracic hypomera with scattered punctation as on pronotum, surface smooth and shiny; prosternal apophysis round, pointing weakly posteriorly. Elytra round circular, 0.95x as wide as long, widest at middle, with completely irregular punctation, punctures fine but larger than pronotal punctures; lateral margins without dentation and visible in dorsal view only at shoulders, humeral angles pronounced; epipleura diminishing somewhat before apex, scattered with a few small punctures, punctures smaller than those on metasternum. Wings present. Abdominal ventrites with punctation as large as on elytra, last visible ventrite 5 unbordered and without modifications. Legs without specific characters, tibiae rounded in cross section and exteriorly without any keels. Aedeagus not examined.
Diagnosis
Menimus dayak sp. n. can be recognised by the small body size, the round body, the 3-segmented antennal club, and the fine dorsal punctation without any elytral rows. Menimus dasun sp. n. is also small and round with a 3-segmented antennal club and irregular dorsal punctation, but this punctation is rough and confluent and the surface is wrinkled. Additionally, M. dayaksp. n. has only slightly globose eyes, whereas in M. dasun sp. n. the eyes are somewhat larger and more globose. For separation from the other species from Borneo and Sumatra, see key.
Etymology
Named in honour of the human ethnic group Dayak, from Borneo.
Menimus grimmi sp. n.
(Fig. 1)
Type material
Holotype (♀): Borneo, Sarawak, Kuban NP, Matang Wildlife Center, 19–22.IX.2008, leg. R. Grimm, CRG.
Paratypes: Borneo, Sabah, Tawau Hills Park, 300 m, 3–6.IV.2015, leg. R. GRIMM, 1 ♀ CRG, 1 ♀ SMNS. – Borneo, Sabah, Kinabalu NP, headquarter, 3–4.VI.1976, leg. R. Fujimoto, 1 ♀, CKA.
Description
Body length 3.5–4.0 mm, body shape broadly parallel. Dorsal side dark brown without colour pattern or metallic shine, surface shiny and without distinct setation, antennae and legs lighter brown. Head with small punctation, sparser on clypeus. Clypeal membrane not exposed. Eyes small, distinctly globose. Antennae (Fig. 1) 10-segmented with separated 4-segmented club. Pronotum widest behind middle, 1.6x as wide as long, anterior corners rounded and not protruding, posterior corners rectangular, lateral margins slightly constricted before base, with fine dentation, basal margin with indistinct border; surface shiny with punctation similar to that on head, disc convex without any impressions; prothoracic hypomera with scattered punctation as on pronotum, surface smooth and shiny; prosternal apophysis not pointing posteriorly. Elytra broadly parallel, 0.8x as wide as long, widest at middle, with punctation irregularly arranged in rows, punctures larger than pronotal punctures; lateral margins with fine dentation and visible in dorsal view nearly over complete length of elytra, humeral angles pronounced; epipleura diminishing somewhat before apex, scattered with a few small punctures, punctures smaller than those on metasternum. Wings present. Abdominal ventrites with punctation as large as on elytra, last visible ventrite 5 unbordered and without modifications. Legs without specific characters, tibiae rounded in cross section and exteriorly without any keels. Aedeagus unknown, only females available.
Diagnosis
Menimus grimmi sp. n. is similar to M. seriepunctatus and M. merkli sp. n., both from Sumatra—see diagnosis of M. merkli sp. n. For separation of the other species from Borneo and Sumatra, see key.
Etymology
Named in honour of Roland Grimm (Neuenbürg), collector of some of the type specimens described herein and eminent explorer of the tenebrionid fauna of Borneo.
Figs. 10–14.
Dorsal view of species of Menimus from Borneo and Sumatra. – 10. M. jacobsoni sp. n., holotype, SMNS. 11. M. lineatopunctatus (Pic, 1930), non-type, Borneo, SMNS. 12. M. kadazan sp. n., holotype, MHNG. 13. M. burut sp. n., holotype, MHNG. 14. M. sabahicus sp. n., holotype, SMNS. Scale bar: 1 mm.
Menimus jacobsoni sp. n.
(Fig. 10)
Type material
Holotype (♀): W Sumatra, Bukittinggi, Gunung Singgalang, 2100–2600 m, 16.X.1990, leg. A. Riedel, SMNS.
Description
Body length 2.6 mm, body shape ovate. Dorsal side dark brown without colour pattern or metallic shine, surface shiny and without distinct setation, anterior part of head, antennae and legs light brown. Head with small punctation, sparser on clypeus. Clypeal membrane not exposed. Eyes small, distinctly globose. Antennae (Fig. 10) 10-seg-mented with fused 3-segmented club. Pronotum widest at basal half, 1.5x as wide as long, anterior corners rounded and not protruding, posterior corners rectangular, lateral margins parallel-sided in basal half, with fine dentation, basal margin with indistinct border; surface shiny with punctation distinctly finer and sparser than on head, disc convex without any impressions; prothoracic hypomera without distinct punctation, surface partly strigose and shiny; prosternal apophysis conical, pointing posteriorly. Elytra short ovate, 0.8x as wide as long, widest before middle, in anterior part with completely irregular punctation, in posterior part with punctation irregularly arranged in rows, punctures distinctly larger than pronotal punctures; lateral margins with fine dentation and visible in dorsal view only in anterior quarter of elytra, humeral angles pronounced; epipleura diminishing somewhat before apex, without distinct punctures. Wings absent. Abdominal ventrites with fine punctation, punctures smaller than on pronotum, last visible ventrite 5 unbordered and without modifications. Legs without specific characters, tibiae rounded in cross section and exteriorly without any keels. Aedeagus unknown, only female available.
Diagnosis
Menimus jacobsoni sp. n. shares the ovate body, the 3-segmented antennal club and the irregular rows of punctures on the elytra with M. riedeli Schawaller, 2016, described from just the female holotype from Peninsular Malaysia. However, M. riedeli is distinctly smaller (1.7 mm), its pronotum is more narrowed in the anterior part, its elytra are rounder and widest at middle, and its elytral rows are more regular in the anterior part of the elytra. The other known round species from Peninsular Malaysia are larger and possess a 4-segmented antennal club and distinctly finer dorsal punctation. For separation from the other species from Borneo and Sumatra, see key.
Etymology
Named in honour of Edward Richard Jacobson (1870–1944), who collected intensively in Indonesia, particularly in Sumatra since 1923, and whose specimens are deposited mainly in the museums of Amsterdam, Genova, Leiden, and London.
Menimus kadazan sp. n.
(Fig. 12)
Type material
Holotype (sex not examined): Borneo, Sarawak, confluence of Sun Oyan and Mujong rivers, E Kapit, 50 m, 18.V.1994, leg. I. Löbl & D. Burckhardt, MHNG.
Description
Body length 1.5 mm, body shape broadly parallel. Dorsal side brown without colour pattern or metallic shine, surface shiny and without distinct setation, antennae and legs lighter brown. Head with small punctation, sparser on clypeus. Clypeal membrane not exposed. Eyes small, slightly globose, somewhat reduced. Antennae (Fig. 12) 10-segmented with fused 3-segmented club. Pronotum widest at middle, 1.5x as wide as long, anterior corners rounded and not protruding, posterior corners rectangular, lateral margins rounded with fine dentation, basal margin unbordered; surface shiny with punctation similar to that on head, disc convex without any impressions; prothoracic hypomera with a few scattered punctures, surface shiny; prosternal apophysis conical, pointing posteriorly. Elytra broadly parallel, 0.6x as wide as long, widest at middle, with irregular punctation only rarely arranged in indistinct rows, punctures feebly larger than pronotal punctures; lateral margins with fine dentation and visible in dorsal view only in anterior half of elytra, humeral angles pronounced; epipleura diminishing somewhat before apex, without distinct punctures. Wings present. Abdominal ventrites with punctures smaller than on elytra, last visible ventrite 5 unbordered and without modifications. Legs without specific characters, tibiae rounded in cross section and exteriorly without any keels. Aedeagus unknown (sex not examined).
Diagnosis
Menimus kadazan sp. n. shares the small body size, the parallel body shape and particularly the elytra with irregular punctation with M. burut sp. n. However, in M. burut sp. n. the antennae are 9-segmented with a separated 3-segmented club, the dorsal punctation is finer, and the elytra are somewhat longer (compare Figs. 12–13). Additionally, in M. burut sp. n. the eyes are not reduced as in M. kadazan sp. n. For separation from the other species from Borneo and Sumatra, see key.
Etymology
Named in honour of the human ethnic group Kadazan, from Borneo.
Menimus kinabalucus sp. n.
(Fig. 5)
Type material
Holotype (♀): Borneo, Sabah, Mt. Kinabalu, 1450–1550 m, 23.V.1987, leg. I. Löbl & D. Burckhardt, MHNG.
Paratype: Borneo, Sabah, Crocker Range, Gunung Alab, 1400 m, 5–6.I.2010, leg. R. Grimm, 1 ♀, CRG.
Description
Body length 2.6–2.8 mm, body shape broad elongate. Dorsal side brown without colour pattern or metallic shine, surface shiny and without distinct setation, antennae and legs lighter brown. Head with small punctation, sparser on clypeus. Clypeal membrane not exposed. Eyes small, slightly globose. Antennae (Fig. 5) 10-segmented with separated 4-segmented club. Pronotum widest at middle, 1.8x as wide as long, anterior corners rounded and not protruding, posterior corners rectangular, lateral margins rounded, with fine dentation, basal margin with indistinct border; surface shiny with punctation distinctly finer and sparser than on head, disc convex without any impressions; prothoracic hypomera without distinct punctation, surface smooth and shiny; prosternal apophysis conical, pointing posteriorly. Elytra broad elongate, 0.7x as wide as long, widest before middle, with punctation irregularly arranged in rows, punctures distinctly larger than pronotal punctures; lateral margins with fine dentation and visible in dorsal view nearly over complete length of elytra, humeral angles pronounced; epipleura diminishing somewhat before apex, scattered with a few small punctures smaller than those on metasternum. Wings present. Abdominal ventrites with punctures as large as on elytra, last visible ventrite 5 unbordered and without modifications. Legs without specific characters, tibiae rounded in cross section and exteriorly without any keels. Aedeagus unknown, only females available.
Diagnosis
Menimus kinabalucus sp. n. shares the body shape and the large punctures of the elytral rows with M. sarawakicus sp. n. However, in M. kinabalucus sp. n. the pronotum is widest at middle and the pronotal punctation is finer and sparser, whereas in M. sarawakicus sp. n. the pronotum is widest in basal half and the pronotal punctation is larger and denser. Menimus kinabalucus sp. n. is also similar to M. grimmi sp. n., but this species is distinctly larger and the punctures of the elytral rows are smaller. For separation from the other species from Borneo and Sumatra, see key.
Etymology
Named after Mt. Kinabalu, in whose vicinity the type series was collected.
Menimus lineatopunctatus (Pic, 1930)
(Figs. 11, 19)
Menimus klapperichi Bremer, 1997: Bremer 1997: 68.
Examined type specimens
2 paratypes of M. klapperichi: Sumatra, Aceh-Selatan, Babahrot, 100 m, 15–20.VIII.1983, leg. J. Klapperich, ZSM.
Other examined specimens
Borneo, Sabah, Gaya Island, 22–23.XI.1996, leg. W. Schawaller, 5 ex., SMNS. – Borneo, Sabah, Poring Hot Springs, Langanan river, 850 m, 14.V.1987, leg. I. Löbl & D. Burckhardt, 7 ex. MHNG, 1 ex. SMNS. – Borneo, Sabah, Mt. Kinabalu NP, Headquarters, 3–4.VI.1976, leg. R. Fujimoto, 1 ex., CKA. – Borneo, Sarawak, Santubong Peninsula, Permai Rainforest Resort, 10–200 m, 23–27.III.2009, leg. R. Grimm, 1 ex., CRG.
Remarks
Synonymy and figure of dorsal view by Schawaller (2016b).
Diagnosis
Body length 2.0 mm, body shape elongated parallel. Clypeal membrane not exposed. Eyes globose. Antennae (Fig. 11) 10-segmented with separated 4-segmented club. Pronotum widest behind middle, 1.8x as wide as long. Elytra parallel, 0.6x as wide as long, with punctation arranged in rows, punctures distinctly larger than pronotal punctures; lateral margins with fine dentation and visible in dorsal view in the anterior half of the elytra. Aedeagus (Fig. 19) with basale as long as apicale, apicale long triangular, rounded at apex.
Published localities
Sumatra: Palembang (type locality of M. lineatopunctatus); Sumatra: Babahrot (type locality of M. klapperichi); W Malaysia: Tioman Island (Schawaller 2016b).
Menimus loebli sp. n.
(Figs. 8, 20)
Type material
Holotype (♂): Borneo, Sabah, Poring Hot Springs. 550–600 m, 9–10.V.1987, leg. I. Löbl & D. Burckhardt, MHNG.
Paratypes: Same data as for holotype, 5 ex., MHNG. – Borneo, Sabah, Mt. Kinabalu NP, Headquarter, 1500 m, 17–23.V.1987, leg. A. Smetana, 1 ex., SMNS. – Borneo, Sabah, Crocker Range, km 63 on road to Tambunan, 1200 m, 19.V.1987, leg. I. Löbl & D. Burckhardt, 1 ex., MHNG. – Borneo, Sabah, Poring Hot Springs, 500 m, 12.V.1987, leg. A. Smetana, 2 ex., SMNS. – Borneo, Sabah, Poring Hot Springs, 480 m, 15.V.1987, leg. A. Smetana, 1 ex., MHNG. – Borneo, Sabah, Poring Hot Springs, 485 m, 19.VIII.1988, leg. A. Smetana, 2 ex., MHNG. – Borneo, Sabah, Sandakan, Sepilok, X.1996, leg. A. Y. C. Chung, 15 ex. NHMUK, 3 ex. SMNS. – Borneo, Sabah, Sandakan, S Lokan, IX.1996, leg. A. Y. C. Chung, 1 ex., NHMUK. – Borneo, Sabah, Sandakan, S. Lokan, III.1997, leg. A. Y. C. Chung, 1 ex., NHMUK. – Borneo, Sarawak, 20 km W Kuching, Gunung Matang, 200–850 m, 25–26.V.1994, leg. I. Löbl & D. Burckhardt, 1 ex., MHNG.
Description
Body length 1.8–1.9 mm, body shape ovate. Dorsal side brown without colour pattern or metallic shine, surface shiny and without distinct setation, antennae and legs light brown. Head without distinct punctation. Clypeal membrane not exposed. Eyes small, slightly globose. Antennae (Fig. 8) 10-segmented with feebly separated 4-segmented club. Pronotum widest in basal half, 2.0x as wide as long, anterior corners rounded and feebly protruding, posterior corners rectangular, lateral margins parallel-sided in basal half, with fine dentation, basal margin unbordered; surface shiny without punctation, disc convex without any impressions but with a transverse row of punctures before base; prothoracic hypomera without distinct punctation, surface smooth and shiny; prosternal apophysis conical, pointing posteriorly. Elytra short ovate, 0.8x as wide as long, widest at middle, elytra with regular punctural rows, punctures larger than those of the basal transverse row on pronotum; lateral margins with fine dentation and visible in dorsal view only in anterior quarter of elytra, humeral angles pronounced; epipleura diminishing somewhat before apex, scattered with a few small punctures smaller than those on metasternum. Wings present. Abdominal ventrites without distinct punctation, last visible ventrite 5 unbordered and without modifications. Legs without specific characters, tibiae rounded in cross section and exteriorly without any keels. Aedeagus (Fig. 20) with finger-like apicale rounded at apex, basale feebly bent in lateral view.
Diagnosis
Menimus loebli sp. n. is characterised by the ovate body shape, the 4-segmented antennal club, the non-punctured head, the non-punctured disc of pronotum but with a transverse row of distinct punctures before unbordered base, and the regular elytral punctural rows. Menimus punggulicus sp. n. also possesses a small round ovate body and a 4-segmented antennal club, but in this species the pronotal disc is completely punctured and without a transverse row at base. The apicale of the aedeagus is finger-like with rounded apex in M. loebli sp. n. and triangular with acute apex in M. punggulicus sp. n. (compare Figs. 20, 22). For separation from the other species from Borneo and Sumatra, see key.
Etymology
Named in honour of IVAN LÖBL (Geneva), collector of several species of Menimus on Borneo, and world-known coleopterist.
Menimus matangicus sp. n.
(Fig. 7)
Type material
Holotype (sex not examined): Borneo, Sarawak, 20 km E Kuching, Gunung Matang, 200 m, 26.V.1994, leg. I. Löbl & D. Burckhardt, MHNG.
Description
Body length 1.5 mm, body shape broadly parallel. Dorsal side brown without colour pattern or metallic shine, surface shiny and without distinct setation, antennae and legs lighter brown. Head with small punctation, sparser on clypeus. Clypeal membrane not exposed. Eyes completely absent. Antennae (Fig. 7) 10-segmented with separated 4-segmented club. Pronotum widest at middle, 1.8x as wide as long, anterior corners rounded and not protruding, posterior corners rectangular, lateral margins rounded, with fine dentation, basal margin unbordered; surface shiny with punctation similar to that on head, disc convex without any impressions; prothoracic hypomera with a few scattered punctures, surface shiny; prosternal apophysis conical, pointing posteriorly. Elytra broadly parallel, 0.7x as wide as long, widest at middle, with punctation irregularly arranged in rows, punctures distinctly larger than pronotal punctures; lateral margins with fine dentation and visible in dorsal view only in anterior half of elytra, humeral angles pronounced; epipleura diminishing somewhat before apex, without distinct punctures. Wings present. Abdominal ventrites with punctures smaller than on elytra, last visible ventrite 5 unbordered and without modifications. Legs without specific characters, tibiae rounded in cross section and exteriorly without any keels. Aedeagus unknown (sex not examined).
Diagnosis
Menimus matangicus sp. n. can be recognised by the small body size, by the 10-segmented antennae with a 4-segmented antennal club, and particularly by the completely absent eyes. Menimus kadazan sp. n. shares with it the small body size and broadly parallel body shape, has somewhat but not completely reduced eyes, and the antenna is also 10-segmented but with a fused 3-seg-mented antennal club and the elytral punctation is not distinctly arranged in rows. For separation from the other species from Borneo and Sumatra, see key.
Etymology
Named after Gunung (= Mount) Matang, where the holotype was collected.
Figs. 15–16.
Dorsal view of species of Menimus from Borneo and Sumatra. – 15. M. dasun sp. n., paratype, SMNS. 16. M. dayak sp. n., holotype, MHNG. Scale bar: 1 mm.
Menimus merkli sp. n.
(Figs. 2, 21)
Type material
Holotype (♂): N Sumatra, Brastagi, Gunung Sibayak, 1450–1900 m, 19–23.II.1991, leg. L. Bocák & M. Bocáková, SMNS.
Paratypes: Same data as for holoptype, 2 ex. NHMB, 1 ex. SMNS. – Sumatra, Sibolangit, without date, leg. E. G. Mjoeberg, 2 ex., NHMB.
Description
Body length 3.2–3.5 mm, body shape elongated parallel. Dorsal side dark brown without colour pattern or metallic shine, surface shiny and without distinct setation, antennae and legs lighter brown. Head with small punctation, sparser on clypeus. Clypeal membrane not exposed. Eyes small, distinctly globose. Antennae (Fig. 2) 10-seg-mented with separated 4-segmented club. Pronotum widest in basal half, 1.9x as wide as long, anterior corners rounded and not protruding, posterior corners rectangular, lateral margins parallel-sided in basal half, with fine dentation, basal margin with indistinct border; surface shiny with punctation distinctly finer and sparser than on head, disc convex without any impressions; prothoracic hypomera with scattered punctation as on pronotum, surface smooth and shiny; prosternal apophysis not pointing posteriorly. Elytra elongated parallel, 0.7x as wide as long, widest at middle, with punctation irregularly arranged in rows, punctures distinctly larger than pronotal punctures; lateral margins with fine dentation and visible in dorsal view nearly over complete length of elytra, humeral angles pronounced; epipleura diminishing somewhat before apex, scattered with a few small punctures smaller than those on metasternum. Wings present. Abdominal ventrites with fine punctures, as large as on pronotum, last visible ventrite 5 unbordered and without modifications. Legs without specific characters, tibiae rounded in cross section and exteriorly without any keels. Aedeagus (Fig. 21) with long finger-like apicale, basale feebly bent in lateral view.
Diagnosis
Menimus merkli sp. n. shares the body size and the 4-segmented antennal club with M. seriepunctatus from Sumatra and M. grimmi sp. n. from Borneo. However, in M. seriepunctatus the elytra are more ovate and the lateral margins are visible only in the anterior half, and the pronotal punctation is larger. In M. grimmi sp. n. the elytra are also parallel and the lateral margins are also visible on the complete length, but the elytra are broader in general in M. grimmi sp. n. than in M. merkli sp. n., and the pronotal punctation in M. grimmi sp. n. is similar to that on the head, whereas in M. merkli sp. n. this punctation is finer than on the head. The aedeagi of M. merkli sp. n. and M. seriepunctatus are similar (compare Figs. 21, 24), the aedeagus of M. grimmi sp. n. is unknown (only females available). For separation from the other species from Borneo and Sumatra, see key.
Etymology
Named in honour of the late Ottó Merkl (1957–2021), former curator of Coleoptera in the Hungarian Museum of Natural History in Budapest and eminent specialist of Tenebrionidae, for his long-term and fruitful cooperation.
Menimus punggulicus sp. n.
(Figs. 9, 22)
Type material
Holotype (♂): Borneo, Sabah, Sapulut, Batu Punggul Resort, 24.VI–1.VII.1996, [collector unknown], SMNS.
Paratypes: Same data as for holotype, 2 ex., SMNS. – Borneo, Sarawak, Gunung Penrissen, 1000 m, 23.V.1994, leg. I. Löbl & D. Burckhardt, 5 ex., MHNG.
Description
Body length 1.3–1.7 mm, body shape ovate. Dorsal side light brown without colour pattern or metallic shine, surface shiny and without distinct setation, antennae and legs light brown. Head with small punctation, sparser on clypeus. Clypeal membrane not exposed. Eyes small, distinctly globose. Antennae (Fig. 9) 10-segmented with separated 4-segmented club. Pronotum widest at base, 2.0x as wide as long, anterior corners rounded and not protruding, posterior corners rectangular, lateral margins rounded, with fine dentation, basal margin unbordered; surface shiny with punctation distinctly finer and sparser than on head, disc convex without any impressions; prothoracic hypomera without distinct punctation, surface shiny; prosternal apophysis conical, pointing posteriorly. Elytra short ovate, 0.8x as wide as long, widest at middle, with punctation irregularly arranged in rows, punctures distinctly larger than pronotal punctures; lateral margins with fine dentation and visible in dorsal view in anterior two thirds of elytra, humeral angles pronounced; epipleura diminishing somewhat before apex, without distinct punctation. Wings present. Abdominal ventrites without distinct punctation, last visible ventrite 5 unbordered and without modifications. Legs without specific characters, tibiae rounded in cross section and exteriorly without any keels. Aedeagus (Fig. 22) with triangular apicale acute at apex, basale feebly bent in lateral view.
Diagnosis
Menimus punggulicus sp. n. shares the small body size and round ovate shape, as well as the 4-segmented antennal club, with M. loebli sp. n., but in M. loebli sp. n. the pronotal disc is without punctation and with a distinct transverse row of punctures before the base. The apicale of the aedeagus is triangular with acute apex in M. punggulicus sp. n. and finger-like with rounded apex in M. loebli sp. n. (compare Figs. 20, 22). For separation from the other species from Borneo and Sumatra, see key.
Etymology
Named after the jungle-topped limestone outcrop Batu Punggul, in whose vicinity part of the type series was collected.
Menimus sabahicus sp. n.
(Fig. 14)
Type material
Holotype (sex not examined): Borneo, Sabah, Sapulut, Batu Punggul Resort, 24.VI–1.VII.1996, [collector unknown], SMNS.
Description
Body length 2.2 mm, body shape elongated parallel. Dorsal side brown without colour pattern or metallic shine, surface shiny and without distinct setation, antennae and legs lighter brown. Head with small punctation, sparser on clypeus. Clypeal membrane not exposed. Eyes small, slightly globose, nearly flat. Antennae (Fig. 14) 9-segmented with separated 3-segmented club. Pronotum widest at middle, 1.4x as wide as long, anterior corners rounded and not protruding, posterior corners rectangular, lateral margins rounded, with fine dentation, basal margin with indistinct border; surface shiny with punctation similar to that on head, disc highly convex without any impressions; prothoracic hypomera with scattered punctation as on pronotum, surface shiny; prosternal apophysis conical, pointing posteriorly. Elytra elongated parallel, 0.6x as wide as long, widest at middle, with punctation irregularly arranged in rows, punctures similar to pronotal punctures; lateral margins with fine dentation and visible in dorsal view only in anterior quarter of elytra, humeral angles pronounced; epipleura diminishing somewhat before apex, without distinct punctures. Wings present. Abdominal ventrites with punctures as large as on elytra, last visible ventrite 5 unbordered and without modifications. Legs without specific characters, tibiae rounded in cross section and exteriorly without any keels. Aedeagus unknown (sex not examined).
Diagnosis
Menimus sabahicus sp. n. is similar at a first glance to M. perakicus Schawaller, 2016 from Peninsular Malaysia, with the small elongate body and the 3-segmented antennal club, but it can be separated from the latter by the 9-segmented antennae and the more convex pronotum. Menimus burut sp. n. also has 9-segmented antennae with a 3-segmented club, but the disc of the pronotum is flatter, the elytra are more elongate, and the elytral punctation is more irregular. For separation from the other species from Borneo and Sumatra, see key.
Etymology
Named after the Malayan federal state Sabah, where the holotype was collected.
Figs. 17–24.
Aedeagus of species of Menimus from Borneo and Sumatra. – 17. M. crockeri sp. n., holotype, SMNS. 18. M. dasun sp. n., holotype, SMNS. 19. M. lineatopunctatus (Pic, 1930), non-type, Borneo, SMNS. 20. M. loebli sp. n., paratype, SMNS. 21. M. merkli sp. n., holotype, SMNS. 22. M. punggulicus sp. n., holotype, SMNS. 23. M. sarawakicus sp. n., holotype, MHNG. 24. M. seriepunctatus Gebien, 1927, holotype of M. malayicus Schawaller, 2016, syn. n., SMNS. Scale bar: 0.5 mm.
Menimus sarawakicus sp. n.
(Figs. 6, 23)
Type material
Holotype (♂): Borneo, Sarawak, 20 km W Kuching, Gunung Matang, 800 m, 13.V.1994, leg. I. Löbl & D. Burckhardt, MHNG.
Paratypes: Borneo, Sarawak, Gunung Penrissen, 1000 m, 23.V.1994, leg. I. Löbl & D. Burckhardt, 1 ♂, SMNS. – Borneo, Sarawak, Mt. Poi, 4000 ft. (= 1220 m), [no date], leg. E. Mjoeberg, 1 ♀, NHMUK.
Description
Body length 3.0–3.5 mm, body shape broad elongate. Dorsal side brown without colour pattern or metallic shine, surface shiny and without distinct setation, antennae and legs lighter brown. Head with large punctation, sparser on clypeus. Clypeal membrane not exposed. Eyes small, slightly globose. Antennae (Fig. 6) 10-segmented with separated 4-segmented club. Pronotum widest in basal half, 1.6x as wide as long, anterior corners rounded and not protruding, posterior corners rectangular, lateral margins parallel-sided in basal half, with fine dentation, basal margin with indistinct border; surface shiny with punctation similar in size to that on head but somewhat sparser, disc convex without any impressions; prothoracic hypomera with scattered punctation as on pronotum, surface flat, shiny; prosternal apophysis conical, pointing posteriorly. Elytra broad elongate, 0.7x as wide as long, widest at middle, with punctation irregularly arranged in rows, punctures similar to pronotal punctures; lateral margins with fine dentation and visible in dorsal view nearly over complete length of elytra, humeral angles pronounced; epipleura diminishing somewhat before apex, scattered with a few small punctures smaller than those on metasternum. Wings present. Abdominal ventrites with punctures as large as on elytra, last visible ventrite 5 unbordered and without modifications. Legs without specific characters, tibiae rounded in cross section and exteriorly without any keels. Aedeagus (Fig. 23) with long finger-like apicale, basale feebly bent in lateral view.
Diagnosis
Menimus sarawakicus sp. n. shares the general body shape and size as well as the 4-segmented antennal club with M. kinabalucus sp. n., but in M. kinabalucus sp. n. the pronotum is widest at middle and the lateral margins are rounded and not parallel-sided before the posterior corners; the dorsal punctation on the head and pronotum is much finer. For separation from the other species from Borneo and Sumatra, see key.
Etymology
Named after the Malayan federal state Sarawak, where the type series was collected.
Menimus seriepunctatus Gebien, 1927
(Figs. 4, 24)
Menimus malayicus Schawaller, 2016, syn. n.
Examined type specimens
2 syntypes of M. seriepunctatus: Sumatra, Gunung Singgalang, without date, leg. E. R. Jacobson, NHMB, 1 ex. designated herewith as lectotype .
Holotype of M. malayicus: W Malaysia, Cameron Highlands, Gunung Beremban, 1–3.IV.1990, leg. A. Riedel, SMNS.
Other examined material
N Sumatra, Medan, Kabanjahe, Gunung Sinabung, 2000 m, 7–8.X.1990, leg. A. RIEDEL, 1 ex., SMNS.
Synonymy
The type specimens of M. seriepunctatus Gebien, 1927 from Sumatra and M. malayicus Schawaller, 2016 from Peninsular Malaysia show no distinct specific differences.
Diagnosis
Body length 3.8–4.1 mm, body shape slightly ovate. Clypeal membrane not exposed. Eyes distinctly globose. Antennae (Fig. 4) 10-segmented with separated 4-seg-mented club. Pronotum widest behind middle, 1.8x as wide as long. Elytra slightly ovate, 0.7x as wide as long, with punctation arranged in rows, punctures distinctly larger than pronotal punctures; lateral margins with fine dentation, visible in dorsal view nearly over complete length of elytra. Aedeagus (Fig. 24) with extremely long apicale, distinctly restricted in basal third.
Published localities
Sumatra:GunungSinggalang(typelocalityofM.seriepunctatus); W Malaysia: Gunung Beremban (type locality of M. malayicus); W Malaysia: Kelantan (Schawaller 2016b).
Identification key to the species of Menimus from Borneo and Sumatra
1 Larger species, body length 3.0–4.0 mm 2
- Smaller species, body length 1.3–2.8 mm 6
2 Antennal club 3-segmented; punctation of pronotum and elytra rough (Fig. 3) M. crockeri sp. n.
- Antennal club 4-segmented; punctation of pronotum and elytra fine 3
3 Body shape ovate; lateral margins of elytra visible in dorsal view only in anterior half (Fig. 4) M. seriepunctatus Gebien, 1927
- Body shape elongated parallel; lateral margins of elytra visible in dorsal view nearly over complete length 4
4 Punctures of pronotum similar in size to punctures of elytral rows as well as head (Fig. 6) M. sarawakicus sp. n.
- Punctures of pronotum distinctly smaller and sparser than on elytral rows 5
5 Punctures of pronotum similar in size and density to those on head (Fig. 1); Borneo M. grimmi sp. n.
- Punctures of pronotum distinctly finer and sparser than on head (Fig. 2); Sumatra M. merkli sp. n.
6 Antennal club 4-segmented 7
- Antennal club 3-segmented 10
7 Body shape broadly parallel 8
- Body shape round or ovate 9
8 Eyes completely absent; body length 1.5 mm (Fig. 7) M. matangicus sp. n.
- Eyes present and slightly globose; body length 2.6–2.8 mm (Fig. 5) M. kinabalucus sp. n.
9 Body length 1.8–1.9 mm; pronotum with non-punctured pronotal disc but with a transverse row of punctures before base (Fig. 8), apicale of aedeagus finger-like, rounded at apex (Fig. 20) M. loebli sp. n.
- Body length 1.3–1.7 mm; pronotum with punctured pronotal disc, without a transverse row of punctures before base (Fig. 9), apicale of aedeagus triangular, acute at apex (Fig. 22) M. punggulicus sp. n.
10 Antennae 9-segmented with separated 3-segmented club 11
- Antennae 10-segmented with separated or fused 3-seg-mented club 12
11 Elytra with punctation irregularly arranged in rows; pronotum widest at middle; eyes smaller, nearly flat (Fig. 14) M. sabahicus sp. n.
- Elytra with completely irregular punctation; pronotum widest behind middle; eyes larger, slighly globose (Fig. 13) M. burut sp. n.
12 Body shape elongated parallel or broadly parallel 13
- Body shape circular, round or ovate 14
13 Body length 2.0 mm; body shape elongated parallel; elytra with punctural rows; antennae 10-segmented with separated 4-segmented club; eyes globose (Fig. 11) M. lineatopunctatus (Pic, 1930)
- Body length 1.5 mm; body shape broadly parallel; elytra with irregular punctation; antennae 10-segmented with fused 3-segmented club; eyes somewhat reduced (Fig. 12) M. kadazan sp. n.
14 Body shape ovate; elytra with irregular punctation in anterior part and with irregular rows in posterior part (Fig. 10) M. jacobsoni sp. n.
- Body shape circular, rounded; elytra with irregular punctation throughout 15
15 Body length 2.4–2.8; elytra with rough and confluent irregular punctation (Fig. 15) M. dasun sp. n.
- Body length 1.3–1.5 mm; elytra with fine and separated punctation (Fig. 16) M. dayak sp. n.
Acknowledgements
For the trustful long-term loan of valuable specimens we cordially thank Kiyoshi Ando (Osaka), Michael Balke (Munich), Christoph Germann (Basel), Roland Grimm (Neuenbürg), Ivan Löbl (Geneva), and Dmitry Telnov (London). Johannes Reibnitz (Tamm) kindly mounted the drawings of the aedeagi on a plate. Erich Spiessberger (Tübingen) and a second, anonymous reviewer kindly improved the manuscript by their various comments and corrections.
