About Zhangixalus arvalis (Lue, Lai & Chen, 1995)
Zhangixalus arvalis is a medium-sized treefrog. Adult males measure 39–46 mm (1.5–1.8 in) in snout–vent length, while adult females measure 60–64 mm (2.4–2.5 in). Its tympanum is visible, but is concealed along its dorsal and posterior edges by a thin supratympanic fold. The fingers and toes have well-developed adhesive discs and webbing; webbing is weakly developed between the fingers, but more prominent between the toes. Its skin is granulated. The dorsal surface color ranges from dark green, green, and yellowish-green to nearly yellow. The upper lip is white, and this white color extends as a stripe along the flanks; the area of the flank below this white stripe is dark purple. The lower lip and the edge of the gular region are silver gray to white. Zhangixalus arvalis is found in disturbed lowland agricultural areas (at elevations below 1,000 m (3,300 ft)) where traditional farming practices are still used. It inhabits bamboo forests, orchards, sugar-cane fields, scrubland, and cultivated fields. This species has a lek-type mating system for reproduction: males form chorus groups on twigs or leaves near the canopy. A female will select a male, carry him down to the damp forest floor (usually a temporary pool), dig a hole, lay foamy eggs into the nest she creates, and then cover the nest with decomposed bamboo leaves or other plant material. Development from egg to metamorphosis takes approximately 40 days. The population of Zhangixalus arvalis is fragmented. It is threatened by habitat loss caused by infrastructure development for industry and human settlement, as well as by agricultural pollution. A key conservation measure for this species is maintaining traditional agricultural practices. Both the Taiwan Wildlife Conservation Act and the IUCN Red List of Threatened Species classify Zhangixalus arvalis as endangered.
