Lutera nigromaculata Ohaus, 1900

Xu, Hao & Zhao, Ming-Zhi, 2024, Synonymic notes in the Southeast Asian genus Lutera Westwood, 1875 (Coleoptera: Scarabaeidae: Rutelinae), Zootaxa 5523 (5), pp. 531-542 : 532-537

Lutera nigromaculata Ohaus, 1900

( Figs. 1–18 , 31, 36, 41 , 46 )

Lutera nigromaculata Ohaus, 1900: 261 (type locality: Montagnes de Lakhon [the northern vicinity of Thakhek, Khammouan Province, Laos]); Ohaus 1918: 39 (catalogued, partim); Ohaus 1934: 112 (catalogued, partim); Kuijten 1988: 87 (discussion on taxonomy); Wada 1998: 369 (in key, holotype mentioned), figs. 4 (male habitus), 16–17 (male genitalia), 23 (male left fore claws), 26b (distribution map); Krajčík 2007: 79 (catalogued); Krajčík 2012: 150 (catalogued); Li et al. 2012: 275 (Pha Ngam, Bokeo Province, Laos).

Parastasia nigromaculata (Ohaus) : Paulian 1959: 84 (redescription based on holotype).

Parastasia ohausi Chûjô, 1966: 33 [replacement name for P. nigromaculata (Ohaus) , preoccupied by P. nigromaculata (Blanchard, 1850) ; Chomtong, Chiang Mai, Thailand]. New synonym.

Parastasia (Lutera) nigromaculata guttata Frey, 1970: 174 (type locality: Khong sedane, Wapik-Hamthong Prov. , Laos [= Khongxedon , Saravan Province, Laos]). New synonym.

Parastasia pauliana Machatschke, 1972: 45 [replacement name for P. nigromaculata (Ohaus) , preoccupied by P. nigromaculata (Blanchard, 1850) ]; Wada 1988: 5 (Chiang Mai, Thailand); Synonymized by Kuijten 1988: 87.

Parastasia nigromaculata guttata Frey : Machatschke 1974: 364 [erroneously listed as subspecies of P. nigromaculata (Blanchard, 1850) ].

Lutera nigromaculata guttata (Frey) : Krajčík 2007: 79 (catalogued); Krajčík 2012: 150 (catalogued).

Type material. Lutera nigromaculata Ohaus, 1900 , holotype, by monotypy, ♀ ( MNHN, Figs. 17–18 ): “148 78 // m. de. Lakhon , Harmand // MUSEUM PARIS, LAKHON, HARMAND 1878 // ♀ // Lutera nigromaculata , type, Ohaus // LUTERA NIGROMACULATA OHAUS , ♀, HOLOTYPE, det. M.L. Jameson 1994 // MNHN, EC1462” . The number of the type specimens was not given in the original publication of L. nigromaculata Ohaus, 1900 , but Ohaus (1905) mentioned that he described this species based on a single female. This female holotype (by monotypy) has been examined by Paulian (1959), but could not be located when Kuijten (1988) tried to examine it, and was later rediscovered in MNHN by M.L. Jameson (see Wada 1998). The collecting data given in the original publication ( Ohaus 1900), i.e., “Lakhon, Tonkin (Dr. Harmand)”, is somewhat different from the label data of the type specimen. The extra word “ Tonkin ” implies that Ohaus thought Lakhon belonged to Tonkin. The location of Lakhon is actually not in Tonkin (roughly equivalent to northern Vietnam) or Malay Peninsula (see Yang 1936), but situated in the valley of the Mekong River. Several attempts have been made by taxonomists (see Huang et al. 2015, page 557), but none has been able to conclude the exact site of Lakhon, although it was further located in the vicinity of present-day Thakhek, Laos, in the boundary of modern Thailand and Laos based on the journey and map of François-Jules Harmand ( Geiser & Nagel 2013; Huang et al. 2015). Fortunately, the most recent archaeological works on the ruins of Muang Kao (near Thakhek) provided a lot of information on the history of Lakhon (Lorrillard 2019; White et al. 2019). Indeed, the name “Lakhon” is a variant of the Thai or Lao word “Nakhon”, which generally refers to the city, town, or power center, but is also specific to an important city during the period of the Kingdom of Lan Xang (14 th –18 th Century).This ancient city Lakhon (now called Muang Kao locally), was situated five kilometers to the south of Thakhek, but was abandoned at the beginning of the 19 th century. The Dutch merchant Gerrit van Wuysthoff passed this city in the year 1641 and clearly indicated it on the left bank of the Mekong River on his map (Lorrillard 2019), while “Lakhon” was misused for a city on the opposite bank by Harmand and other contemporary French explorers who visited Indo-China around the second half of the 19th century. This later “Lakhon” actually is nowadays Nakhon Phanom in eastern Thailand (Lorrillard 2019).According to his journey and map, Harmand sailed upstream along the Mekong River and arrived in Lakhon (i.e., Nakhon Phanom) on May 2 nd, 1877, and two days later he crossed the Mekong River to collect zoological specimens in “Montagnes de Lakhon”, a karst mountains area (17°34’56.5”N, 104°51’26.7”E, Fig. 46 ) in the northern vicinity of Thakhek ( Harmand 1880). “M. de Lakhon” on the handwritten label of the type specimen of L. nigromaculata apparently refers to here. This mountain area is located in the region on the left bank of the Mekong River where the Laotians live, but was also controlled by Siam at that time and later evolved into the territory of modern Laos after being colonized by France. Lakhon became a well-known type locality because of the large number of zoological specimens collected by Harmand, but the labels of some material were simply written as “Lakhon”, and thus it cannot be determined whether it came from the city or the mountains on the opposite bank of the Mekong. This probably is the reason why the location of Lakhon was generally considered in either Thailand or Laos ( Descarpentries & Villiers 1967; Breuning 1978; Lin et al. 2009; Alonso-Zarazaga & Roca-Cusachs 2017). Harmand returned to Lakhon on May 27 th, and shipped out the specimens before continuing his expedition to the east. These specimens arrived in Phnom Penh (capital of Cambodia) 11 months later, and Harmand got back to France in the year 1878; which matches the number “78” given in the round label of the holotype ( Fig. 18 ).

Parastasia (Lutera) nigromaculata guttata Frey, 1970 , lectotype, by present designation, ♂, ( BPBM, Figs. 7–10 ): “ LAOS: Wapik-hamthong Prov. , Khong Sedone , 30.V.1965 // Native Collector, BISHOP MUS. // TYPUS // Parastasia nigromaculata ssp. guttata n. ssp., det. G. Frey, 1968”. Paralectotypes: 1♂ ( NHMB, Figs. 11–13 ), “ LAOS: Wapik-hamthong Prov., Khong Sedone, 16.V.1965 // Native Collector, BISHOP // PARATYPUS // Parastasia nigromaculata ssp. guttata n. ssp., det. G. Frey, 1968”; 1♀ ( BPBM, Figs. 14–16 ), “ LAOS: Wapik-hamthong Prov., Khong Sedone, 30.V.1965 // Native Collector, BISHOP MUS. // PARATYPUS // Parastasia nigromaculata ssp. guttata n. ssp., det. G. Frey, 1968 // +1”.

Parastasia (Lutera) nigromaculata guttata Frey, 1970 was described based on three Laotian specimens collected from Khong Sedone (15°34’N, 105°49’E; as “Khongsedane” in the original publication). This is the only taxon without type designation in the publication of Frey (1970), although one of the three type specimens was found bearing a label “TYPUS” and the remaining two had attached a label “ PARATYPUS ”. According to Art. 72.1.1 ( ICZN 1999), all three specimens should be treated as syntypes. Considering the new synonym introduced herein, the male specimen in BPBM with a red label “TYPUS” is here designated as lectotype to enhance the stability of nomenclature.

Additional material examined (18♂♂, 8♀♀). INDIA: 1♀ ( ZMPC), 1990.VI.3, Darjeeling, Sikkim ; THAILAND: 6♂♂, 25♀♀ ( KWPC) Chiang Mai, Doi Pui, 1985.VI ; 1♂, 7♀♀ ( KWPC) Chiang Mai, Maetang , 1989.VIII.2 ; 1♀ ( KWPC) Chiang Mai, Fang, 1993.VIII ; 1♀ ( THNHM) Chiang Mai Prov., Fang Dist., Pha Hom Pok National Park , 19°58’02.7”N, 99°09’13.7”E, 2008.V.26, T. Jeenthong leg. ; 1♂ ( ZMPC), Chiang Mai, Chiangdao Hill Resort , 19°33′29.19″N. 99°04’33.34’E, 2019.VII.1–15, Ustinov V. leg. ; 1♂, 1♀ ( KWPC) Phrae, Wieng Ko Sai National Park , 1985.V.18, H. Akiyama leg. ; 1♂ ( KWPC) Phrae, Wang Chin, 1992.VIII ; 1♀ ( ZMPC), Phrae Prov, Wangchin , 1991.VI.20 ; 1♂ ( CZPC) Mae Hong Son env., Thai/Burma border , 1300 m, 1993.VI.17–21, J. Schneider leg. ; 1♀ ( THNHM) Kalasin Prov., Kuchinarai Dist., Phu Si Than Wildlife Sanctuary headquarters, 2007.VI.7, light trap, W. Jaitrong leg. ; 1♀ ( THNHM) Nakhon Ratchasima Prov., Sakaerat Environmental Research Station , 1968. V.25, S. Sililert leg. ; 1♀ ( THPC) Nakhon Ratchasima Prov., Sakaerat Environmental Research Station , 2019.VII.6, T. Hongsuwong et al. leg .; 1♂ ( WPPC) Chanthaburi Prov., Pong Nam Ron Dist., Thap Sai Subdist. , Chatrium Golf Resort Soi Dao , 2017.V.14, W. Pathomwattanurak leg. ; 1♀ ( RBMF) Kanchanaburi Prov., Ban Sanephong , 2023. VI.4, K. Jiaranaisakul leg. ; VIETNAM: 1♂, 1♀ ( MYNU) Binh Thuan Prov., Dong Tien, 2020.V, native collector leg .; 2♂♂ ( MYNU) Binh Thuan Prov., Dong Tien , 2022.V, native collector leg .; LAOS: 3♂♂ ( ZMPC) Luang Prabang, near Pak Long, Hoi Khua , at light, 2024.V.17.

Redescription. General. Body broadly ovoid and strongly convex. All external setae yellowish brown, dorsal surface almost glabrous. Head. Dorsal surface yellow with two black spots on frons, marginal portions darkened. Clypeus nearly semicircular, uneven, apex weakly emarginated, anterior margin moderately raised; clypeus and two black spots on frons densely striolate, other portions of frons bearing sparse and elongated punctures. Frontoclypeal suture broadly interrupted medially. Eye canthus simple, not extending beyond outermost point of eye. Antenna reddish brown, length of antennal club equal to the combined length of antennomeres 2–7. Labrum not exposed dorsally. Mandible with blackish brown and upright apex, anterior margin mesially with a small and blunt protrusion. Galea and maxillary palp reddish brown, both mandible and maxilla with dense and long setae at outer margin. Mentum yellowish brown, margins darkened, anterior margin weakly trilobed, surface with sparse short setae.

Pronotum. Yellow to brown, darkened at anterior and posterior margins. Strongly convex, about 1.58 times as wide as long, widest near middle. Anterior and posterior margins broadly and strongly protruding respectively; anterior marginal membrane absent. Sides weakly convergent posteriad in posterior half, broadly curved at middle, then strongly convergent anteriad in anterior half. Posterior marginal line broadly interrupted before scutellum, other marginal lines complete. Anterior angle weakly protruding, posterior angle rounded. Surface with 11 evenly distributed large black spots: one row including four spots at anterior third and another including five spots at basal third, near each lateral margin a single spot at middle; punctures on surface sparse and minute, but dense and rather coarse on the three lateral spots, all marginal lines with elongated punctures. Scutellum. Yellow to brown, margin black. Semicircular in shape, anterior margin slightly sinuate, lateral margin somewhat rounded. Surface with sparse and minute punctures. Elytra. Yellow to brown. Convex, almost as wide as long, widest at middle. Surface uneven, humeral umbones weakly prominent. Strial punctures large, punctures on primary striae as large as punctures on secondary striae, primary stria I well defined by a longitudinal row of regular punctures, other striae unrecognizable; the whole surface with sparse small punctures, denser on lateral portions. Epipleura with a row of dense, short to moderately long setae. Ventral thoracic surface. Yellow, anterior part of prosternum and three markings on center of metasternum brown, narrow margins dark brown; sparsely punctate, with moderately long setae, mesosternum with transverse striolation and dense, short setae; mesosternal process not produced beyond mesocoxae, apex wide and truncate, weakly curved. Abdomen. Abdominal ventrites not abbreviated at middle, with shallow and transverse striolation, each ventrite with a transverse row of moderately long setae near posterior margin; pygidium sparsely punctate, shallowly striolate basally, with some long setae at apex. Legs. Tibiae with brown longitudinal patches; protibia strongly tridentate; protarsus thickened, small internomedial protuberance of tarsomere 5 absent in protarsus but present in meso- and metatarsi; all larger tarsal claws split at apex, lower branch of inner protarsal claws conspicuously longer and wider than upper branch, with a rounded apex. Male genitalia. As in Figs 31, 36, 41 . Parameres symmetric, concavity of ventral margin varies significantly.

Sexual dimorphism. Clypeus more triangular in female ( Figs. 4–5 ), basal third weakly convergent anteriad, apical third rather strongly convergent to the strongly bilobed apex, apical angle each rounded and upright; Lateral portions of frons also strongly striolate. Protarsi not thickened, lower branch of protarsal claw equal to the upper one and slightly wider.

Measurements. Body length 14.0– 19.8 mm, width 8.3–11.9 mm.

Variability. The size of the black spots on the dorsal surface is variable, and sometimes the adjacent two are connected.

Differential diagnosis. This species is easily distinguished from the congeners by the unique pattern of black spots on the dorsal surface and the presence of a black groove along the sutural costa on elytron.

Distribution. Nepal, Thailand, Laos, Vietnam (new record), India (new record).

Remarks. Arrow (1917) merged Lutera into the genus Parastasia , resulting in a secondary homonymy between L. nigromaculata Ohaus, 1900 and P. nigromaculata (Blanchard, 1850) . However, he did not review the names of congeners distributed outside British India to propose replacement names for potential homonyms. Ohaus did not agree with this synonymization and did not place these two species in the same genus in the two world catalogues he compiled ( Ohaus 1918, 1934). Chûjô (1966) noticed this homonymy earlier than Machatschke’s (1972) new catalogue, but the new name he proposed, P. ohausi , was published in a Japanese journal that was not indexed in the Zoological Record. Several European coleopterists, including Vladimír Balthasar (1897–1978), collaborated with Chûjô on several reports in the same issue of this journal. Nevertheless, for unknown reasons, this paper, which includes not only this new name but also a new species of the genus Adoretus Dejean, 1833 , has hitherto been overlooked. Presently, the validity of the genus Lutera has been widely accepted, and thus the replacement name P. ohausi Chûjô, 1966 is synonymized here.

Frey (1970) named a subspecies L. nigromaculata guttata from southern Laos. Based on the original description and the examination of the type specimens ( Figs. 7–16 ), this subspecies is undoubtedly a synonym of L. nigromaculata Ohaus , as the putative distinctive features stated by Frey, i.e., larger maculae on the dorsal surface and an additional black line along the elytral suture, are absolutely identical to those of L. nigromaculata .

This beetle was previously known to occur only in Thailand and Laos ( Chûjô 1966; Frey 1970; Wada 1988; Li et al. 2012). According to the distribution map drawn by Wada (1998), it is widely distributed in Indo-China as well as Nepal ( Fig. 46 ). However, no precise localities have been provided by Wada. This species is newly recorded from South Vietnam and India here with detailed collecting information.

Figures

FIGURE 46. Known distribution of Lutera nigromaculata Ohaus, 1900 (black dots) and L. nigrita Ohaus, 1930 (black triangles). Type localities are underlined, and the open dot in Nepal is a record from Wada (1998) without precise location.

FIGURES 1–6. Habitus of Lutera nigromaculata Ohaus, 1900 from Vietnam. 1, 4, dorsal view; 2, 5, lateral oblique view; 3, 6, ventral view.

FIGURES 7–16. Type specimens of Parastasia (Lutera) nigromaculata guttata Frey, 1970. 7–10, lectotype (in dorsal, ventral, and frontal view) and labels (photograph by James H. Boone, BPBM); 11–13, paralectotype (in dorsal and lateral view) and labels (photograph by Christopher German, NHMB); 14–16, paralectotype (in dorsal and lateral view) and labels (photograph by James H. Boone, BPBM).

FIGURES 17–24. Type specimens of Lutera spp. 17–18, female holotype of L. nigromaculata Ohaus, 1900 and labels (©MNHN); 19–20, inauthentic type of L. nigromaculata in MFNB (photograph by Bernd Jäger); 21–24, female holotype of L. nigrita Ohaus, 1930 (in dorsal and lateral view), head, and labels (photograph by Bernd Jäger, MFNB).

FIGURES 31–45. Male genitalia of Lutera species (31–35, dorsal view; 36–40, lateral view; 41–45, ventral view;). 31, 36, 41, L. nigromaculata Ohaus, 1900 from Thailand; 32–35, 37–40, 42–35, L. nigrita Ohaus, 1930: 32, 37, 42, from Luzon Island; 33, 38, 43, from Mindoro Island; 34, 39, 44, from Negros Island; 35, 40, 45, from Mindanao Island