Breeding and rearing the Critically Endangered Lake Oku Clawed Frog (Xenopus longipes Loumont and Kobel 1991)

The Lake Oku Clawed Frog Xenopus longipes is a Critically Endangered, dodecaploid anuran endemic to Lake Oku in Cameroon. An ex situ population of this species was established at Zoological Society of London (ZSL), London Zoo in 2008, as well as at several other institutions, with the intention of providing data on the biology and husbandry of this species. We report the first captive breeding of the species. Adult frogs maintained under environmental conditions designed to mimic field data produced clutches of 7–300 eggs; eggs measured 1.23 mm in diameter, and were laid singly after a period of 6.5 hours in axial amplexus. Spawning took place only during the day. Tadpoles hatched in 2–3 days and development was very long compared to congeners, lasting 193–240+ days until metamorphosis. Tadpoles grew very large (maximum 79 mm total length), particularly compared with the relatively small adult size (maximum 36 mm Snout to Vent Length [SVL]). Tadpoles proved to be highly sensitive to total dissolved solids (TDS) in the water and only thrived when low levels (20 mg/L) were used. Metamorphosis concluded with an SVL of 19–25 mm and F1 animals began first sexual activity at 5–6 months post metamorphosis. These data will inform future husbandry in captivity as well as illuminating facets of biology previously unknown and difficult to determine in the field.