A new species of Lepidotrigona (Hymenoptera: Apidae) from Thailand with the description of males of L. flavibasis and L. doipaensis and comments on asymmetrical genitalia in bees

Abstract

<jats:p>We describe Lepidotrigona satun Attasopa and Bänziger new species from southern Thailand based upon associated males and females (workers). The new species is a member of the L. ventralis species group, which is otherwise represented in Thailand only by L. flavibasis and L. doipaensis. We also describe the males of the latter two species, associated with nests from close to their type localities in northern Thailand. Lepidotrigona doipaensis Schwarz and L. flavibasis (Cockerell) had previously often been misidentified as L. ventralis (Smith), a species confirmed only from Borneo. Based upon differences in male morphology, especially of the metasomal sterna, we conclude that the male described from Vietnam by Sakagami (1975) as belonging to L. flavibasis represents an undescribed species. Our findings support previous taxonomic studies that highlight the importance of including males in the differentiation of closely related species of meliponines and their association with workers. The three species whose males we describe have asymmetric penis valves with the asymmetry differentially developed among the three. We compare this genitalic asymmetry with that known from a different apid genus, Tarsalia. </jats:p>

Description of the male of Lepidotrigona nitidiventris (Smith, 1857), redescription of the female holotype and additional morphological data on the workers (Hymenoptera: Apidae: Meliponini)

“…Lepidotrigona has been divided into three groups based primarily on size (Schwarz, 1939;Rasmussen, 2008Rasmussen, , 2013. This classifi cation was followed by Attasopa et al (2018). The groups are the small L. "ventralis", the midsize L. "terminata" and the large L. "nitidiventris" groups according to the length of body and forewing.…”

“…Species level separation involves a combination of body size, colour of integument on metasomal terga, colour of hairs on the head and mesosoma (Schwarz, 1939;Sakagami, 1975). There are also differences among species and species groups in the male genitalia (Attasopa et al, 2018) although males are not known for all species. As is the Oxford University Museum of Natural History, Oxford, United Kingdom (OUMNH).…”

“…The holotype of L. nitidiventris and Thai specimens were examined morphologically under a Nikon SMZ1500 stereomicroscope and measurements were taken with an ocular micrometer (calibrated with a stage micrometer). The metatibial ratio, as used in our analysis, is the maximum width of the metatibia compared to its maximum length (see fi g. 1C in Attasopa et al, 2018). Images were taken at PCYU (the Packer Collection at York University, Toronto, Ontario, Canada, using a Visionary Digital BK plus with a Canon 40DSLR camera and processed with Photoshop CS6 (Adobe Inc.).…”

“…The word "hairs" without additional structural description refers to simple hairs; specialized hairs are noted as plumose hairs, robust hairs, etc. We use the word "setae" for small strong sclerotized portion on terminalia such as apical setae on S5 (as fi gs 2A2-C2 in Attasopa et al, 2018). Terminology and measurements follow Michener (2007) with some terms and additional measurements as in Attasopa et al (2018) and the term metapostnotum refers to what is often called the propodeal triangle.…”

“…We use the word "setae" for small strong sclerotized portion on terminalia such as apical setae on S5 (as fi gs 2A2-C2 in Attasopa et al, 2018). Terminology and measurements follow Michener (2007) with some terms and additional measurements as in Attasopa et al (2018) and the term metapostnotum refers to what is often called the propodeal triangle. Flagellomere, and metasomal sternum and tergum represented by F, S, and T, respectively, with the number following the letter indicating which segment.…”