Infestation and Seasonal Fluctuation of Gamasid Mites (Parasitiformes: Gamasida) on Indochinese Forest Rat, Rattus andamanensis (Rodentia: Muridae) in Southern Yunnan of China

A 12-month consecutive investigation was made at Jingha village in southern Yunnan of southwest China from April 2016 to March 2017. A total of 2053 Indochinese forest rats (Rattus andamanensis Blyth, 1860) were captured and examined, which account for 84.69% (2053/2424) of all the animal hosts (rodents and other small mammals) at the investigation site. And 39.82% (13,531/33,980) of gamasid mites were identified from the body surface of R. andamanensis and they belong to 41 species, 10 genera, 3 subfamilies and 2 families. Of the 41 species of gamasid mites identified from R. andamanensis, Laelaps nuttalli Hirst, 1915 and Laelaps echidninus Berlese, 1887 were the most dominant with 70.63% and 20.67% of constituent ratios respectively. In monthly fluctuations of all the gamasid mites on R. andamanensis, the constituent ratio (Cr) and overall infestation mean abundance (MA) of the mites in 12 months showed two obvious peaks in January (winter season) and June (summer season). However, the two dominant mite species, L. nuttalli and L. echidninus, showed different patterns of seasonal fluctuations. Laelaps nuttalli occurred throughout the year, and its Cr and MA showed two prominent peaks in winter season (December and January) and summer season (June), which belongs to the summer-winter type of seasonal fluctuation. Laelaps echidninus also occurred on R. andamanensis throughout the year, but its Cr and MA showed only one peak in winter season (December and January), which belongs to the winter type of seasonal fluctuation. A negative correlation existed between two climatic factors (temperature and rainfall) and the infestations (Cr, prevalence PM and MA) of two dominant mite species (L. nuttalli and L. echidninus) on R. andamanensis (p < 0.05). Temperature and rainfall are considered to be two key factors that influence the seasonal fluctuations of the mites on the studied rat species.

A new species of Zhangixalus (Anura: Rhacophoridae), previously confused with Zhangixalus smaragdinus (Blyth, 1852)

We describe a new species of Zhangixalus from southern Yunnan of China, Vietnam, and Thailand based on morphological and molecular evidence. The new species had been confused with Zhangixalus smaragdinus (Blyth, 1852) in the past. Zhangixalus pachyproctus sp. nov. can be distinguished from Z. smaragdinus morphologically by the protruding vent in adult males, large thick grey reticular mottles below the white stripe on flank, more oblique snout in profile and wider head, longer snout, greater internarial distance, larger tympanum and longer hindlimb. The new species can be distinguished from other species of Zhangixalus with green dorsum by the following combination of characters: body size larger (SVL of adult males: 74.2–83.3 mm; SVL of adult female: 102.4 mm); dorsum smooth; narrow white stripes along edge of the lower jaw, body sides, outer side of limbs and above the vent; absence of brown bands on canthus rostralis, upper eyelid and supratympanic fold; webbing between fingers and toes complete except between the first two fingers; and internal single subgular vocal sac. Phylogeny based on comparison of 16S rRNA sequences suggests that the new species is the sister taxon to Z. smaragdinus and the two species differ by 7.63% in the uncorrected pairwise distance of 16S sequences.