Amasa striatotruncata ( Schedl, 1936 )

Smith, Sarah M., Beaver, Roger A. & Cognato, Anthony I., 2020, Taxonomic Changes For Indo-Malayan Ambrosia Beetles (Coleoptera: Curculionidae: Scolytinae: Xyleborini), The Coleopterists Bulletin 74 (1), pp. 37-40 : 37

Amasa striatotruncata ( Schedl, 1936) , status restored

Xyleborus striatotruncatus Schedl 1936: 29 . Amasa striatotruncatus [sic] (Schedl): Wood and

Bright 1992: 684.

Hulcr and Cognato (2013) placed the Papua New Guinean species A. striatotruncata and Amasa umbratula ( Schedl, 1975) in synonymy with Amasa schlichii (Stebbing, 1914) . Hulcr and Cognato (2013) considered A. schlichii to be an extremely morphologically variable species that could only be defined by the shining declivital surface and a type 4 ( Hulcr et al. 2007) antennal club with segment 1 small, convex, and corneous and segments 2 and 3 larger, mostly corneous, and prominent on the anterior and posterior sides of the club. We examined the holotype of A. schlichii (in the Forest Research Institute, Dehradun, India) and specimens from China, India, Taiwan, Vietnam, the lectotype of A. striatotruncata (in Naturhistorisches Museum, Wien, Austria), the holotype of A. umbratula (in Naturhistorisches Museum), and additional specimens of A. striatotruncata and A. umbratula from Papua New Guinea (in Michigan State University A. J. Cook Research Collection and University of Florida Forest Entomology Laboratory). Mitochondrial COI DNA sequences were generated for four individuals of A. schlichii (three from Vietnam and one from China), one of A. striatotruncata (from Papua New Guinea), and one of A. umbratula (from Papua New Guinea).

Discrete morphological differences were found to separate the species. Amasa schlichii has a strongly shagreened and dull (rarely opalescent) declivity that is never shiny, a granulate and inflated declivital interstria 1, and impunctate declivital interstriae. Amasa striatotruncata is distinguished from A. schlichii and A. umbratula by a very smooth and strongly shiny declivity, declivital interstriae 1 feebly inflated, armed with a few granules near the apex, and impunctate declivital interstriae. COI sequences revealed large differences among all three species. Amasa striatotruncata differed from A. schlichii and A. umbratula by 14.9–15.3% and 16.8%, respectively; A. umbratula differed from A. schlichii by 12.5–12.7% (Cognato et al. in press). Given the COI differences were greater than 10–12% (Cognato et al. in press) and the species exhibit discrete morphological differences, we view them as three species rather than a single morphologically variable species as proposed by Hulcr and Cognato (2013). We were unable to locate any specimens from New Guinea that share the morphology of A. schlichii , and it is very likely that the species is restricted to mainland Asia. Its occurrence in Papua New Guinea is doubtful.