Range and elevation extension for the Yunnan Water Snake, Trimerodytes yunnanensis (Rao & Yang, 1998) (Serpentes, Colubridae), from Thailand and some notes on its natural history

Trimerodytes yunnanensis (Rao & Yang, 1998), Mountain Water Snake, mainly occurs at elevations of more than 1,000 m above sea level (a.s.l.). We provide both a range extension to Lampang, Thailand, and the lowest known elevation record for this species at 400 m a.s.l. This record is also the southernmost known occurrence of T. yunnanensis and the genus as a whole. In addition, a morphological description of the juvenile, ecological notes in the field, and feeding habits in captivity are provided.

Floresorchestia kongsemae sp. n. a new species (Crustacea: Amphipoda: Talitridae) from Kasetsart University, Bangkok, Thailand

Background

The genus Floresorchestia Bousfield, 1984 is widely distributed in terrestrial and marine coastal habitats. It has been found from coastal South Africa through to the Indo-Pacific region and the Caribbean Sea in Central America. Two species of Floresorchestia have been reported in Thailand, Floresorchestia boonyanusithii Wongkamhaeng et al. 2016 and Floresorchestia buraphana Wongkamhaeng et al. 2016. This work reports on a new species of Floresorchestia found at Kasetsart University in a man-made pond and neighbouring areas.

New information

Classification of the new species was achieved by considering the left mandible 5-dentate; gnathopod 2 posterior margin merus carpus and propodus of gnathopod 2 covered in palmate setae, palm reaching about 33% along posterior margin; uropod 3 peduncle with three robust setae; telson dorsal mid-line half the length of its breadth and four robust setae per lobe.

A snail-eating snake recognizes prey handedness

Specialized predator-prey interactions can be a driving force for their coevolution. Southeast Asian snail-eating snakes (Pareas) have more teeth on the right mandible and specialize in predation on the clockwise-coiled (dextral) majority in shelled snails by soft-body extraction. Snails have countered the snakes' dextral-predation by recurrent coil reversal, which generates diverse counterclockwise-coiled (sinistral) prey where Pareas snakes live. However, whether the snake predator in turn evolves any response to prey reversal is unknown. We show that Pareas carinatus living with abundant sinistrals avoids approaching or striking at a sinistral that is more difficult and costly to handle than a dextral. Whenever it strikes, however, the snake succeeds in predation by handling dextral and sinistral prey in reverse. In contrast, P. iwasakii with little access to sinistrals on small peripheral islands attempts and frequently misses capturing a given sinistral. Prey-handedness recognition should be advantageous for right-handed snail-eating snakes where frequently encountering sinistrals. Under dextral-predation by Pareas snakes, adaptive fixation of a prey population for a reversal gene instantaneously generates a sinistral species because interchiral mating is rarely possible. The novel warning, instead of sheltering, effect of sinistrality benefitting both predators and prey could further accelerate single-gene ecological speciation by left-right reversal.