Amphibians (frogs)

Cape Ghost Frog, Purcell's Ghost Frog / Kaapse Spookpadda

Heleophryne purcelli

Size Adult females may attain a body length of 56 mm and males 47 mm.

Description The adult frog has a somewhat flattened body; an eye with a dark, horizontal band running through it and a vertically elliptical pupil; and long limbs with large, spatulate adhesive pads at the tips of the fingers and toes. While the fingers lack webbing, the toes are extensively webbed up to the last segment of the fifth toe (and this sometimes extends to the tip). No thumb-like metacarpal tubercle is present. A glandular fold is present behind the eye (above the tympanum). The upper body surface is generally green to brown and covered with well-defined reddish brown spots and patches of variable size. There are distinct transverse bands present on the limbs of most specimens. The underside colour is mainly whitish except for the limbs which are fleshy-orange, while the skin is densely granular except on the throat. The advertisement call is a clear high-pitched ringing note produced at a rate of about one per second.

Biology This species is endemic to certain mountain ranges in the winter rainfall region of the Western Cape . It only occurs in undisturbed habitat within the Mountain Fynbos or Afromontane Forest vegetation types and is dependent on clear, fast flowing, perennial mountain streams for breeding. When they are not breeding, ghost frogs utilize damp terrestrial habitat surrounding the streams and have even been found sheltering under rocks several hundred metres away from the nearest watercourse. They are well adapted for climbing in steep, rocky terrain and enter rock crevices and caves. By means of the adhesive pads on their fingers and toes they are able to climb virtually any wet or damp surface, including smooth, vertical rock faces.

Breeding takes place from early to mid-summer (about October to January) when stream flow has reduced following the rainy season. The males can be heard calling both during the day and after dark. They call from positions adjacent to waterfalls, cascades and small rapids such as from rock cracks or from rocks either on the banks of streams or protruding from the water. Ghost frogs have a complex courtship display but actual egg-laying has not been observed. The eggs, which are laid singly, have been found scattered in exposed positions in small quiet, shady pools connected to the main stream. They are large and yellow with each one contained in a stiff jelly capsule. Clutch sizes have been found to vary from 50 to 208 eggs. The eggs hatch after four or five days. Initially the young tadpoles live off a large reserve of yolk, where after they feed by grazing over algae-covered rocks, and these “feeding trails” can be seen on rocks in quieter pools. The distinctive tadpoles attain a length of about 60 mm and are well-adapted for a life in fast flowing streams. In particular, they have large sucker-like mouths for clinging to rocks in fast flowing water and even use their mouths to climb slippery rock faces such as waterfalls. During the day, the tadpoles are usually found attached to the underside of submerged rocks. They are slow developers, taking over twelve months to develop into frogs, and are generally ready to leave the water during the period from March to May.

Distribution This species is endemic to certain Cape Fold Mountains in the western part of the Western Cape Province.

Distribution in GCBC This extends from the higher mountains of the Cederberg southwards into the Groot Winterhoek Mountains.

Conservation status Not threatened.

Threats No serious threats.

Current studies This species was assessed in the Southern African Frog Atlas Project (published in 2004). A project to investigate the genetic diversity in the Cape Fold Mountain ghost frogs is currently underway.

 

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