Tetragonula (Tetragonula) laeviceps ( Smith, 1857 )

Ascher, John S., Soh, Zestin W. W., Chui, Shao Xiong, Soh, Eunice J. Y., Ho, Benjamin M., Lee, John X. Q., Gajanur, Anya R. & Ong, Xin Rui, 2022, The bees of Singapore (Hymenoptera: Apoidea: Anthophila): First comprehensive country checklist and conservation assessment for a Southeast Asian bee fauna, Raffles Bulletin of Zoology 70, pp. 39-64 : 49

31. Tetragonula (Tetragonula) laeviceps ( Smith, 1857) Smooth-headed Stingless Bee

All available records of this species in Singapore were from central forest areas, such as Bukit Timah, Dairy Farm, and Nee Soon. This species has a complicated taxonomic history that will be treated in detail elsewhere. To summarise concisely, we conclude that the small Tetragonula discovered by Wallace in Singapore and described as Trigona laeviceps Smith, 1857 (see Rasmussen & Michener, 2010), was redescribed as new, from Peninsular Thailand, as Trigona (Tetragonula) pagdeniformis Sakagami, 1978 (new synonymy). Sakagami (1978) applied the name T. laeviceps to a different, slightly larger bee species with weaker thorax hair bands and a redder metasoma. This larger bee corresponds, with respect to Singaporean material, to Tetragonula valdezi (the most common stingless bee in Singapore; material from elsewhere is composite, including additional species in this complex). We concur with a note on the identity and neotype of the very similar Tetragonula laeviceps ( Rasmussen & Michener, 2010) that the name T. laeviceps applies to a smaller “form” (actually a separate species) of T. laeviceps auct. as opposed to the larger “form” (i.e., T. valdezi ) but we do not think their lectotype designation was warranted because in our view minor discrepancies noted between Smith’s (1857) description and putative type material in the Oxford University Museum of Natural History collection (see Baker, 1993) do not definitively refute its authenticity. Imprecisions are to be expected in historical descriptions from this era, when the first extensive documentation of “exotic” bees were initiated ( Baker, 1996). In general, we concur with a recent classification of Tetragonula by Engel et al. (2017), but we regard T. pagdeniformis as a synonym of T. laeviceps . In addition, we recognise T. valdezi , described from Singapore and widespread in Malaysia, as provisionally distinct from the very similar but darker-tailed (i.e., less red) T. testaceitarsis ( Cameron, 1901) described from Pattani in southern Thailand. The latter seems to be a geographic replacement in the continental (monsoonal) Southeast Asia to the north of Sundaland. Further integrative taxonomic studies are needed. A recent paper on the bees of Bukit Timah ( Ascher et al., 2019) continued to employ the taxonomy of Sakagami (1978), so Tetragonula (Tetragonula) laeviceps (Smith) as reported there corresponds to T. valdezi as presently understood, whereas T. (T.) pagdeniformis (Sakagami) reported therein corresponds to true T. laeviceps of Wallace (and sensu Rasmussen & Michener, 2010; Engel et al., 2017, in part; but not Sakagami, 1978) as recognised here.