Overview
The Alta Verapaz Spikethumb Frog (Plectrohyla teuchestes) is a heavily armored, stream-dwelling hylid treefrog native exclusively to the cloud-draped mountain slopes of eastern Guatemala. Belonging to a specialized group of torrent frogs known as spikethumbs, it is named for the sharp, dagger-like prepollical bony spine protruding from the base of each thumb, which males employ in intense territorial wrestling matches along cascading mountain rapids.
Biology and Physical Characteristics
Plectrohyla teuchestes possesses a rugged, tuberculate skin texture shaded in mottled mossy green, copper-brown, and bronze, providing flawless camouflage against lichen-encrusted boulders in torrential stream splash zones. Its limbs are thick and muscular, terminating in enlarged, adhesive toe pads that adhere securely to wet, slick rock faces. The trademark prepollical spine on each hand is a formidable, keratinized bony spike that can puncture the skin of rival males or predators.
Behavior and Ecology
Active by night, these frogs perch along the spray zones of waterfalls and rushing mountain torrents, vocalizing with low, raspy clicks that cut through the roaring sound of rushing water. Their tadpoles possess enormous, cup-shaped oral suctorial disks that function as vacuum clamps, allowing them to cling to polished bedrock within fast-flowing rapids without being swept downstream while scraping diatoms from underwater rocks.
Conservation and Human Impact
Evaluated as Critically Endangered by the IUCN, Plectrohyla teuchestes suffered devastating population crashes following the arrival of the amphibian chytrid fungus (Batrachochytrium dendrobatidis) across Mesoamerica. In addition, conversion of cloud forests into coffee plantations, stream siltation from unpaved road construction, and pesticide runoff threaten the remaining isolated stream populations. Protecting intact riparian corridors within the Sierra de las Minas Biosphere Reserve is paramount for its survival.
Interesting Factoid
The ‘spikethumb’ on this frog’s hand is a literal concealed weapon: during breeding battles, competing males lock arms in vigorous chest-to-chest combat, using their sharp thumb daggers to puncture each other’s skin in defense of prime rock territories.
Last updated: October 2026