English name: Darkside Narrowmouth Frog (aka “Dark-sided Chorus Frog”)
Scientific name: Microhyla heymonsi
Thai name: Ung khang da
Description: Up to 2.5cm long. A tiny squat frog with a pointed nose that gives the entire body a triangular shape. Light brown on top, sometimes with a thin light line going down the back. May have other faint markings on the body and legs. Sides are characteristically dark, though sometimes the dark coloration only appears on the very top of the sides. Underside is creamy white.
Tadpoles are approximately 1.5cm long, with a “guitar” shape and a protruding mouth. They are dark in the middle and transparent elsewhere.
Call: A series of clicking runs, similar to the Ornate Narrowmouth Frog.
Similar Species: Inornate Froglet is flatter, has distinct black markings, and will hop around like a flea when exposed.
Ornate Narrowmouth Frog has a dark marking on the back and lighter sides.
Asian Painted Frog is larger and heavier with a broader snout and cream-colored band on the side.
Habitat: Found in forest, agricultural areas, and empty lots. Hides under cover during the day, coming out at night or during rain. Breeds in rain puddles, ponds, marshes, and other shallow bodies of still water.
Contribution to the ecosystem: Helps control ants and other small insects. Provides food for birds, snakes, lizards, larger frogs, and even large insects and arachnids.
Danger to humans: No danger to humans.
Conservation status and threats: Because of its large population and ability to utilize a range of habitats (including those affected by humans), it has no conservation threats at this time.
Interesting facts: Though the Darkside Narrowmouth Frog and Ornate Narrowmouth Frog have a similar size and diet, I have almost never found them in the same exact area. All species have some sort of ecological “niche” that they prefer – and if their “niches” were the same, then these two otherwise similar species would compete with each other and one would eventually outcompete and eliminate the other. In my experience the Darkside Narrowmouth Frog is often found in areas with permanent water sources, while the Ornate Narrowmouth Frog is more often found in areas with temporary water sources. This may or may not be the ecological difference that keeps them from competing directly, but it would take more extensive research to verify these anecdotal observations.
Wild Singapore: Dark-sided Chorus Frog
Ecology Asia: Dark-sided Chorus Frog
The IUCN Red List: Microhyla heymonsi
Thailand Office of Environmental Planning and Policy: A Checklist of Amphibians and Reptiles in Thailand