Romer's Tree Frog

Romer's Tree Frog
Conservation status
Endangered (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Amphibia
Order:	Anura
Suborder:	Neobatrachia
Family:	Rhacophoridae
Genus:	Liuixalus
Species:	L. romeri
Binomial name
Liuixalus romeri (Li, Che, Bain, Zhao & Zhang, 2008)

Romer's Tree Frog (Liuixalus romeri)^[1] is a species of frog endemic to Hong Kong. With an average snout-vent length of 1.5 - 2.5 cm, it is the smallest amphibian recorded in the territory. Despite its common name, it belongs to the Rhacophoridae family, instead of the Hylidae.

Physical descriptions

The female frog is slightly larger than the male. The body of the creature is tan brown, with the underside white. An X-like marking, made up of two crooked black lines, can be seen on the dorsum. Sometimes the lines do not meet medially, thus leading to a chevron marking posteriorly. Underneath the X-like marking lies another upside-down V-like marking.The skin is peppered with fine granules. A distinct fold extends from the eye to the foreleg.

Romer's Tree Frog has a triangular but blunt snout with brown-spotted lips. Between the eyes is a dark bar, which extends to the eyelids. The hindlegs are long, slender, and barred with irregular brown-to-black crossbands. All digits have small toe pads, which allow the frog to hang on tree branches or leaves.

Ecology and behaviour

The habitat of the frog is well-wooded areas near a small stream or other water source suitable for breeding. The creature usually sits on low bushes, buries itself in fallen leaves, or rests on bare ground. The frog has been recorded solely from 4 of the outlying islands in Hong Kong, namely Lantau Island, Lamma Island, Po Toi Island and Chek Lap Kok.

Its tadpoles and eggs are susceptible to predation by the introduced mosquitofish, and it is only able to breed in places the fish has yet to colonise. The frog breeds in shallow water from early March to September. The male has a shrill staccato call. The female glues up to 120 eggs onto submerged plant debris, stones or vegetation. The tadpoles, brown in colour, require 4 to 6 weeks to metamorphose in captivity.

Adults feed on termites, and such small insects as crickets and arachnids such as spiders. The frog is strictly nocturnal. It lives for approximately 3 years in the wild, but the female is reproductively active only for 2 breeding seasons.

Discovery and conservation

Romer's Tree Frog was named after the late J. D. Romer, who first discovered it in a cave on Lamma Island in 1952. That population disappeared in 1953 due to the collapse of the cave. Once thought to be extinct, the frog was re-discovered on the island in 1984.

Over 200 individuals of the species were rescued from Chek Lap Kok in 1992, before the construction of the Hong Kong International Airport. The captives were bred successfully and the offspring were released into 8 selected sites in Hong Kong Island and New Territories. The frogs in 7 of the sites survived. Surprisingly, a very small number of the creatures also survives in Chek Lap Kok.

An endangered species, Romer's Tree Frog is protected under the law of Hong Kong (Wild Animals Protection Ordinance, Cap. 170). Part of Ngong Ping in Lantau, a site that supports the largest population of the frog, has been designated as a Site of Special Scientific Interest in May 1999.

References

• Lau & Ermi (2004). Chirixalus romeri. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 09 May 2006. Database entry includes a range map and justification for why this species is endangered.
• Stephen J. Karsen, Michael Wai-neng Lau and Anthony Bogadek (1998). Hong Kong Amphibians and Reptiles, 2nd ed.. Hong Kong: Provisional Urban Council. ISBN 962-7849-05-7.

Multimedia

• Watch the episode 香港蛙蛙叫 in the series 山水傳奇 produced by RTHK (in Cantonese, with standard Chinese subtitles)
• Listen the slide-by-slide presentation, A successful conservation & reintroduction program for Chirixalus romeri, Romer’s Tree Frog in Hong Kong, made by Chris Banks from Zoos Victoria during the Husbandry and Hygiene Conference in 2004.

External links

• An introduction by the WWF Hong Kong
• An introduction by the Agriculture, Fisheries and Conservation Department of HKSAR
• Philautus romeri in Hong Kong: a frog re-introduction to a degraded tropical landscape (an article written by the researchers from the University of Hong Kong)

Footnote

1. ^ Li, Che, Bain, Zhao, and Zhang, 2008, Mol. Phylogenet. Evol., 48: 311. The frog was previously classified under other genera: initially Philautus (Smith, 1953) and later Chirixalus (Bossuyt & Dubois, 2001).