Nectophrynoides viviparus (Tornier, 1905) - Robust Forest Toad, Morogoro Tree Toad

Morogoro Tree Toad, Nectophrynoides viviparus (Photo: ©Tim Davenport / WCS)		Family:	Bufonidae (True Toads)
		Origin:	Tanzania
		Adult Snout-to-Vent Length:	Male: 58 mm (2.20 inches); Female: 60 mm (2.36 inches)
		IUCN (Red List) Status:	Vulnerable (VU)
		CITES Listing Status:	Appendix I
		Similar Species:	Nectophrynoides asperginis, Kihansi Spray Toad

Meet the Frog Part 7: the Morogoro Tree Toad, Nectophrynoides viviparus

This is quite an interesting species of toad, as I am sure you will agree. Its taxonomic name suggests that it is viviparous, which means it produces live young rather than laying eggs. Technically it is ovoviviparous, meaning the eggs develop in the female of the species and then hatch inside her, just before being "born" in a live birth. Females give birth to up to 114 toadlets, but the average is more likely around 70. This "birthing" takes place over a 24 hour period.

The skin is fairly smooth for a Bufonid. Large glands are present on the limbs. These glands, and the parotoid glands, often contrast with the color of the body. Coloration can be quite variable - the species can be gray, reddish, pale green, yellow, or dark olive, depending on the current background where the toad finds itself. The underside can vary from jet black to pure white, and is often mottled.

Morogoro Tree Toads can be found in forest, grass lands at the forest's edge, bamboo forest, and montane forest in the Udzungwa, Uluguru, and Ukinga mountains. Generally this species is terrestrial, but sometimes it can be found in vegetation, climbing up to a meter off the ground. The toad is commonly found on the forest floor or under rotting logs. During the dry winter, males are known to call from the leaf litter or from trees. They call at temperatures as low as 6 °C (42 °F).

Trade in the entire Nectophrynoides genus is prohibited under the Convention on International Trade in Endangered Species (CITES), which lists the genus in CITES "Appendix I".

Mating Kihansi Spray Toads, Nectophrynoides asperginis, at the Toledo Zoo, USA (Photo: ©2009 Tim A. Herman / Toledo Zoo)

On a sadder note, a close relative of the Morogoro Tree Toad is the Kihansi Spray Toad, Nectophrynoides asperginis. The Kihansi Spray Toad, now extinct in the wild, was discovered in 1996 and was found only in the spray zone around the Kihansi and Mhalala waterfalls in the mountains of Udzungwa. You will recall from earlier in this article that N. viviparus is found in these mountains too. The Kihansi Spray Toad had evolved to take advantage of the unique conditions offered by the area around these waterfalls. Unfortunately, the Tanzanian government decided to build a hydroelectric dam on the river above the falls, restricting the water flow severely. In fairness to the Tanzanians, they did work with conservationists to establish captive breeding programs, and two of these (the Toledo Zoo in Ohio, USA, and the Bronx Zoo, also in the USA) have successfully bred the species.

In 2003 the fungal disease Batrachochytrium dendrobatidis (known as "chytrid" or "BD") was found in the wild toads. This disease is widely credited with wiping out or severely damaging amphibian populations around the world. It is unclear whether the fungus has played a role in the decline of the Kihansi Spray Toad. The threat of the disease to the genus as a whole is difficult to ascertain, as initial surveys have documented chytrid in widespread locations in the Udzungwas, including many areas where the anuran faunas appear to be unaffected. Several pesticides known to be lethal to amphibians have been documented in the water of the Mhalala and Kihansi waterfalls, and a sediment flushing event upstream at the dam immediately preceded the population crash.

The last wild Kihansi Spray Toad was sighted in 2005. For now, the species' fate lies in the successful captive breeding efforts that will hopefully allow the re-introduction of this beautiful toad to the wild in the future.

Interestingly, Tim Herman notes that an undescribed species of Nectophrynoides (initially thought to be N. tornieri) can still be found in the forests around the waterfalls in the Kihansi gorge.

References

1. Herman, T. A. Personal Communication Many thanks to Tim for sharing his insight and contribution to this article

2. Channing, Alan & Howell, Kim M. Amphibians of East Africa 2006 Cornell University Press

Other Resources

If you have more resource links please submit them - please note that we only link family friendly sites.

Discuss this article in the dedicated thread on FrogForum.

©2010 Kurt Kunze

Written by Kurt Kunze and John P. Clare.

Last updated 23rd February 2010.

About the Authors
Kurt Kunze is a self educated herpetologist and a member of the New England Herpetological Society based in South Weymouth, Massachusetts, USA. He has been a herpetologist for the past ten years or so, before that he was a professional aquarist, working with everything from guppies and goldfish to sharks and octopus. He has worked for the Museum of Science in Boston in their Live Animal Center and for the Museum of Natural History of Harvard University as a gallery guide. At the MoS, he worked with various reptiles and amphibian species, including alligators, snakes, lizards, turtles, and frogs. At Harvard, he did live animal demonstrations and educated visitors in paleontology, particularly on Mesozoic reptiles. His husbandry skills were refined by working at the MoS, as well as with the late Barbara Bonner DVM at her Turtle Hospital. Kurt has also co-authored the questionnaire for Assumption College's Science Olympiad on herpetology for the past two years. Kurt makes his home in Billerica, Massachusetts, USA, along with his small "zoo", which includes various scorpions, fish, salamanders, turtles, snakes, and of course, frogs. His interests center on the Hylids, Dendrobatids, Bufonids, & Microhylids. Kurt has bred the Red-Eyed Leaf Frog, Agalychnis callidryas, and has plans to breed the Red-Banded Rubber Frog, Phrynomantis bifasciatus, the False or Southern Tomato Frog, Dyscophus guineti, and the Fire-Bellied Toad, Bombina orientalis.
John P. Clare hails from Ireland and is the founder of FrogForum.net and Caudata.org. He has had an interest in amphibians since the age of 4. He holds a degree in Natural Science and a PhD in Chemistry. His primary research interests are the synthesis and study of molecules for the remediation of freshwater pollutants. In his spare time he likes to photograph amphibians and reptiles in the wild. His photographs have been published in everything from children's books to university level textbooks. His photos have featured in such diverse media as the programme "Brink" on the Science Channel in the US, Texas Parks and Wildlife literature, the Boston Museum of Science, Palais de la Découverte Science Museum in Paris, France, and several Zoological Institutions' brochures and exhibit ID cards.