A monograph on the genus Tetraserica from the Indochinese region (Coleoptera, Scarabaeidae, Sericini) Author Fabrizi, Silvia Author Dalstein, Vivian Author Ahrens, Dirk text ZooKeys 2019 837 1 155 http://dx.doi.org/10.3897/zookeys.837.32057 journal article http://dx.doi.org/10.3897/zookeys.837.32057 1313-2970-837-1 4A18822935804DB7B1229F131F6A0AC8 4A18822935804DB7B1229F131F6A0AC8 Tetraserica dongnaiensis sp. n. Figures 18, 47 Type material examined. Holotype: ♂ "Museum Leiden Viet Nam (Dong Nai Prov.) Cat Tien N.P.: along Dong trail, 9.iv-19.v.2007. Leg. C. van Achterberg, R. de Vries, E. Gasso , Miracle & Nguyen Than Mahn/ humid lowland forest; in malaise traps; 250 m. 11°26'20.6"N , 107°25'42"E / 960 Sericini Asia spec." (RMNH). Paratypes: 4 ♂♂ "Museum Leiden Viet Nam (Dong Nai Prov.) Cat Tien N.P.: along Dong trail, 9.iv-19.v.2007. Leg. C. van Achterberg, R. de Vries, E. Gasso , Miracle & Nguyen Than Mahn/ humid lowland forest; in malaise traps; 250 m. 11°26'20.6"N , 107°25'42"E " (RMNH, ZFMK), 2 ♂♂ "Museum Leiden Viet Nam (Dong Nai Prov.) Cat Tien N.P.: along Dong trail, 1.iv-13.v.2007. Leg. May Phu Quy, Nguyen Than Mahn/ humid lowland forest; in malaise traps; 250 m, 11°26'20.6"N , 107°25'42"E " (RMNH). Description. Length of body: 10 mm; length of elytra: 7.5 mm; maximum width: 6.4 mm. Surface of labroclypeus and disc of frons glabrous. Smooth area anterior to eye twice as wide as long. Eyes moderately large, ratio of diameter/interocular width: 0.62. Ratio of length of metepisternum/metacoxa: 1/1.61. Metatibia short and wide, ratio width/length: 1/2.36; basal group of dorsal spines of metatibia at first third of metatibial length. Aedeagus: Fig. 18 A-C Habitus: Fig. 18D. Figure 18. A-D Tetraserica dongnaiensis sp. n. (holotype) E-H T. phatoensis sp. n. (holotype) A, E aedeagus, left side lateral view C, G aedeagus, right side lateral view B, F parameres, dorsal view D, H habitus. Scale bars: 0.5 mm. Habitus not to scale. Female unknown. Variation. Length of body: 9.1-10.5 mm; length of elytra: 6.9-7.9 mm; maximum width: 5.8-6.8 mm. Diagnosis. Tetraserica dongnaiensis sp. n. differs from all other Tetraserica species that have long median phallobasal lamina with simple left and simple right parameres at base (without brush of spines), by the left paramere being split behind basal third into two filiform branches, and the right paramere being short and curved. Etymology. The new species is named with reference to its occurrence in the Dong Nai province (adjective in the nominative singular).