JHR 88: 51-60 (202 1) ore JOURNAL OF “eer eewee openscces journal doi: 10.3897/jhr.88.73969 RESEARCH ARTICLE () Hymenopter a 2 https://jhr.pensoft.net The international Society of Hymenopteriss REGEARCH First record of the bee genus Bathanthidium (Bathanthidium s. str.) Mavromoustakis (Hymenoptera: Megachilidae) from Vietnam: Description of a new species and a key to species Ngat Thi Tran'?, Lam Xuan Truong'”, Toshko Ljubomirov’, Lien Thi Phuong Nguyen!” | Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Nehia Do, Cau Giay, Hanoi, Vietnam 2 Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Nehia Do, Cau Giay, Hanoi, Vietnam 3 Institute of Biodiver- sity and Ecosystem Research, Bulgarian Academy of Sciences, 1, Tzar Ossvoboditel Boulevard, Sofia 1000, Bulgaria Corresponding author: Lien Thi Phuong Nguyen (phuonglientit@gmail.com) Academic editor: Jack Neff | Received 5 September 2021 | Accepted 19 October 2021 | Published 30 December 2021 http://zoobank.org/03725F23-6D56-4E73-AE 1 1-16B8F53E4880 Citation: Tran NT, Truong LX, Ljubomirov T, Nguyen LTP (2021) First record of the bee genus Bathanthidium (Bathanthidium s. str.) Mavromoustakis (Hymenoptera: Megachilidae) from Vietnam: Description of a new species and a key to species. Journal of Hymenoptera Research 88: 51-60. https://doi.org/10.3897/jhr.88.73969 Abstract The little-known bee genus Bathanthidium Mavromoustakis, 1953 of the family Megachilidae is reported for the first time from Vietnam. A new species, Bathanthidium (Bathanthidium s. str.) paco Tran & Nguyen, sp. nov. from Hoa Binh province is described and illustrated. A nest of the new species is reported from a wooden house. An updated identification key to all known species of the subgenus Bathanthidium s. str. is also provided. Keywords Apoidea, Anthidiini, identification key, morphology, taxonomy Introduction Bathanthidium is a small genus of anthidiine bees occurring in eastern Asia (Michener 2007; Ascher and Pickering 2021). It is an uncommonly collected genus with most species known from a small number of specimens and some species lack associated Copyright Ngat Thi Tran et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 52 Ngat Thi Tran et al. / Journal of Hymenoptera Research 88: 51-60 (2021) males. Currently, the genus consists of 12 species belonging to three subgenera: sub- genus Bathanthidium s. str. Mavromoustakis, 1953 with three species, Manthidium Pasteels, 1969 with five species and Stenanthidiellum Pasteels, 1968 with four species (Niu et al. 2019). China is considered the distribution center of the genus because almost all its species occur in this country (Niu et al. 2019). In Vietnam, knowledge concerning the taxonomy of the genus Bathanthidium has been extremely limited as the country has been under sampled for bees. We here report this genus for the first time for the Vietnamese fauna, with a species belonging to sub- genus Bathanthidium s. str. described as new to science. A nest site of the new species is also described. In addition, an updated key to all recognized species of the subgenus Bathanthidium s. str. is provided. Materials and methods The materials examined in the present study are deposited in the Hymenopteran col- lection of the Institute of Ecology and Biological Resources (IEBR), Hanoi, Vietnam. The adult morphological and color characters were examined with a Nikon SMZ745 stereomicroscope. Images were photographed with a Nikon SMZ800N digital stereo microscope, and with ILCE-5000L/WAP2 digital camera attached on that. Photo- graphs were combined with Helicon Focus 7 software to achieve focus stacked images. Finally, all files were processed with Adobe Photoshop CS6. The morphological terminology used in the description follows Michener (2007). Measurements of body parts follows Niu et al. (2004): Body length: measured from the base of antennal socket to the apex of metasoma (in dorsal view), head length: measured from the apico-median margin of clypeus to the upper margin of vertex (in frontal view), head width: measured at the widest point of the head across the compound eyes (in frontal view), eye width: the greatest width of eye (in lateral view), genal width: the greatest width of the gena (in lateral view), mesosomal width: measured between the outer rims of the tegulae (in dorsal view). ‘The abbreviations S and T (1, 2, 3...) refer to numbered metasomal sterna and terga, respectively. Results Genus Bathanthidium Mavromoustakis, 1953 Subgenus Bathanthidium s. str.: Dianthidium (Bathanthidium) Mavromoustakis, 1953: 837. Type species: Dianthidium bifoveolatum Alfken, 1937, by original designation. Diagnosis. According to Michener (2007) and Niu et al. (2012), the diagnosis of the genus Bathanthidium is as follows: Small to moderate-sized species. Body all black or Genus Bathanthidium from Vietnam 53 black with yellow markings, with the yellow bands broken on anterior terga; epistom- al suture generally straight; medially divided, smooth-floored mesoscuto-mesoscutos- cutellar sulcus; preoccipital ridge not carinate; omaular carina absent; pronotal lobe with carina weak or absent; scutellum rounded or medially emarginated, in profile rounded or at least not sharp and not overhanging metanotum; propodeum with a fovea behind spiracle; 2°! m-cu slightly exceeding the apical margin of 2°4 submar- ginal cell; arolia present and large; median S4 of both sexes with pectinate hairs; $5 of the male with pectinate hairs; T6 of the male simple; T7 of the male ranges from simple to trilobed, with the median lobe longest; front coxa of the male normal, without spine. Bathanthidium (Bathanthidium s. str.) paco Tran & Nguyen, sp. nov. http://zoobank.org/3769E63C-29F2-45 52-843 1-620E056400CE Figs 1A—-H, 2A-E, 3A-I Material examined. Holotype: Vietnam: 2, Hoa Binh, Mai Chau, Pa Co, Hang Kia — Pa Co Natural Reserve, 20°44'36"N, 104°53'42"E, alt. 1340 m, Nest#VN-HB-2020- Bath-01, 24 Jun. 2020, Nguyen LTP, Nguyen CQ, Tran NT & Mai TV leg., deposited in IEBR. Paratypes: ViETNAM: 2 G, same data as holotype, deposited in IEBR. Diagnosis. Based on the presence of fovea behind propodeal spiracle rounded and delimited by strong carina, the new species belongs to subgenus Bathanthidium s. str. This species can be distinguished from all other known species of subgenus Bathanthidium s. str. by the following combination of characters: in the both sexes, mandible widened apically, the lowest tooth slightly rounded; in female, clypeus and mandible in entirely black, paraocular area with thin, yellowish-orange marking ex- tending along the inner margin to the top of the eye, scutellum entirely black, T1 with lateral small, dull orange markings, T2—T5 basally with yellowish-orange bands, T1-— T2 apically with dull orange bands, the rest of T3—T'5 with dull orange to dirty yellow bands, T6 entirely black; in male, T7 of trilobed, median lobe longest and broadest, lateral lobe short, acute and curved inwards, male genitalia large, forked gonostylus with two unequally branches, penis valves with blade shape. Description. Female (Figs 1, 2). Holotype: Body length 8.5 mm, fore wing length 8.0 mm, head width 2.1 mm, and mesosomal width 3.8 mm. Head: \n frontal view subcircular, approximately 1.2 times as wide as long (Fig. 1A), gena about 0.7 times as wide as eye (Fig. 1G). Mandible widened apically, with 4 teeth, gradually elongate from the first tooth to the fourth tooth, the lowest tooth slightly round- ed (Fig. 1B). Clypeus broader than long. Supraclypeal area and clypeus slightly convex. Mesosoma: Fore wing with two submarginal cells, the first sub-equal in length to second, basal vein nearly straight and meeting Cu vein at acute angle, 2°¢ m-cu vein exceeding apical margin of the second submarginal cell, stigma nearly twice as long as broad (Fig. 1E). Outer margin of axilla slightly curved. Scutellum convex, with two foveae at basal margin, each fovea about four times as wide as long and with api- 54 Ngat Thi Tran et al. / Journal of Hymenoptera Research 88: 51-60 (2021) Figure |. A-H Bathanthidium (Bathanthidium s. str.) paco Tran & Nguyen, sp. nov., holotype, female A head in frontal view B mandible in frontal view C propodeum in lateral view, showing the fovea behind propodeal spiracle D mesoscutum and scutellum in dorsal view E fore wing in dorsal view F habitus in dorsal view G habitus in lateral view H nest entrance. Scale bars: 5 mm (H); 1 mm (A, C, E, F,G); 0.5 mm (B,D). cal margin slightly emarginated medially (Fig. 1D). Fovea behind propodeal spiracle rounded, delimited by strong carina, basal zone of propodeum distinct laterally, with regular and shiny pits (Fig. 1C). Genus Bathanthidium from Vietnam 55 Figure 2. A-E Bathanthidium (Bathanthidium s. str.) paco Tran & Nguyen, sp. nov., holotype, female A middle tibia in dorso-lateral view, showing the tibial spine B distitarsus of hind leg in frontal view, showing the arolium C metasoma in lateral view D T6 in dorsal view E mesoscutum and scutellum in dorsal view. Scale bars: 1 mm (C, D, E); 0.5 mm (A, B). Metasoma: V1 with carina on basal margin, T6 with margin round apically (Fig. 2C—D). T6 with large, rough, dense punctures on basal haft and with small, extreme- ly dense punctures on remain part. Fore and middle tibiae in dorso-lateral view with a short spine (Fig. 2A), hind tibia without a spine. Arolia present (Fig. 2B). Pygidial plate absent. Punctation. Clypeus with large, rough and dense punctures, except the apex with small punctures; frons, vertex, and gena with round, large and dense punctures. Mesoscutum with round and dense punctures, size of the punctures smaller and shallower than that on frons. Scutellum with round and dense punctures, size of punctures uneven. T1—T5 with round, small and sparse punctures on basal half and smaller and denser punctures on remain part. 56 Ngat Thi Tran et al. / Journal of Hymenoptera Research 88: 51-60 (2021) I Figure 3. A-I Bathanthidium (Bathanthidium s. str.) paco Tran & Nguyen, sp. nov., paratype, male A head in frontal view B mesoscutum and scutellum in dorsal view C T4~—7 in dorsal view D fore wing in dorsal view E abdomen in latero-ventral view F habitus in dorsal view G habitus in lateral view H genitalia in dorsal view I genitalia in ventral view. Scale bars: 1mm (A, B, D, E, F, G); 0.5 mm (C, H, I). Genus Bathanthidium from Vietnam SF ‘+ af Pajacel Islands BAY OF BENGAL CAI ARABIAN SEA 5 ‘ a . . ’ ‘ ‘ fe: q gra ts Spratly Islands; > ‘v= a © B. (Bathanthidium s. stv.) bifoveolatum A B. (Stenanthidiellum) emeiense @ B. (Bathanthidium s. stv.) fengkaiense & 4 Z A B, (Stenanthidiellum) rabopunctatum © &. (Bathanthidium s. str.) hainanense tes Hathirnthiiend's did pater ania A B. (Stenanthidiellum) sibiricum a 2B, (Manthidium) atriceps © B. (Manthidium) barkamense @ B. (Manthidium) bicolor © OB. (Manthidium) binghami = 1,000 500 0 O B, (Manthidium) moganshanense SS—————_ Kilometers 70°E 80°E 90°E 100°E 110°E 120°E Figure 4. Distribution map of Bathanthidium species in the Indomalayan region. Pubescence. Clypeus, paraocular area and frons with sparse, short and pale white hairs. Mandible with extremely short, brownish-yellow hairs except for some longer hairs at outer margin. Vertex, mesoscutum, scutellum with short, brownish-yellow hairs. S2-S6 with scopa. Colour. Paraocular area with thin, yellowish-orange marking extending along the inner margin to the top of the eye (Fig. 1). T1 with lateral small, dull orange markings, T2-1T5 basally with yellowish-orange bands, T1—T2 apically with dull orange bands, the rest of [3—T'5 with dull orange to dirty yellow bands, T6 entirely black (Fig. 2C-E). Fore and middle femora apically, fore tibia in inside view with dull orange. Male (Fig. 3). Body length 9-9.2 mm, forewing length 8.5—8.7 mm. Head about 1.2 times as wide as long, gena about 0.7 times as wide as eye. Most characteristics of the male are similar to those of the female, except for the following: Metasoma: 17 trilobed, median lobe longest and largest, lateral lobe short, acute and curved inwards (Fig. 3C). Male genitalia large, gonostylus forked with two un- equal branches, penis valve with blade shape (Fig. 3H-I). Colour. Clypeus yellow, supraclypeal area with small yellow marking, paraocu- lar area with thin, long and yellow to yellowish-orange marking extending along the inner margin to the top of the eye (Fig. 3A). Mandible basally with dull yel- low marking. Gena with yellowish-orange markings near the apical margin of the eye, mesoscutum latero-anteriorly with small yellowish-orange spots (sometimes 58 Ngat Thi Tran et al. / Journal of Hymenoptera Research 88: 51-60 (2021) absent), scutellum entirely black (Fig. 3B). Inner surface of fore femur apically, fore tibia, fore basitarsus, middle femur apically, and middle tibia with dull or- ange markings. Tl with lateral small, light yellowish-orange markings; T2 medi- ally with light yellowish-orange bands, T3—T5 basally with light yellowish-orange bands; T1, [2, 15 apically with dirty yellow bands; most of the rest of T3 and T4 with dirty yellow bands; [6 and T7 entirely black (Fig. 3C, F—G). Fore and middle femora apically, fore tibia in inside view with dull orange. Pubescence. lhe median part of S3 orange, apical margin of S2—S3 with pale white to dull orange feather combs, S4 shiny on basal half and with short, dense, pale white hairs on remain part and simple hair comb in apical margin, S5 shiny on basal half and short, sparser, pale yellow hairs on remaining part with black, serrated papillae at apical margin (Fig. 3E). Remarks. This species is most similar to B. (Bathanthidium) bifoveolatum (Alfken, 1937), but can be easily distinguished from the later by the mandible with the lowest tooth slightly rounded in both sexes (mandible with the lowest tooth acute in both sexes of B. bifoveolatum); clypeus entirely black in female (clypeus laterally with yellow markings in female of B. bifoveolatum); mandible basally with dull yellow marking in male (mandible with yellow marking extending from base to nearly top in male of B. bifoveolatum); mesoscutum latero-anteriorly with small faint yellowish-orange spots or absent, scutellum, pronotal lobe black in both sexes (mesoscutum anteriorly and scutellum apically with thin and long yellow marking interrupted medially; pronotal lobe with yellow marking basally in both sexes of B. bifoveolatum); T2 with yellowish-orange entirely bands, not interrupted medially in both sexes (T2 laterally with yellow markings in both sexes of B. bifoveolatum). Nest biology. A nest was discovered in a wooden plank in the door of a house, the entrance hole of the nest with a diameter of about 4 mm (Fig. 1H). A female specimen was observed and collected when flying out from the nest. Male specimens were col- lected in the garden behind the wooden house. Distribution. Northern Vietnam (Hoa Binh province). Etymology. ‘The specific name refers to the type locality, Pa Co commune in Hoa Binh province, it is treated as a noun in apposition. An updated key to the species of the subgenus Bathanthidium s. str. (Based on Niu et al. 2019, males of B. fengkaiense Niu & Zhu, 2019 and B. hainanense Niu, Wu & Zhu, 2012 are unknown) | Flavellum Osseonten ted Memiale:: isan cotstvateac 0 Rkps Sethe los siete pa oatnes 2 = Flacelliniie tl =