Banna Caecilian

This animal looks like earthworm at first glance. The eyes are minute, without lids, and are buried below the skin. The animals have a sensory tentacle between the eye and nostril on each side of the body. Along the length of the body there are about 360 cutaneous ring-like folds. The body coloration is brownish-black above, with a yellow, longitudinal band on each side running down the length of the body. The larvae are completely aquatic and have a short tail with a thin laterally compressed fin that extends from the body of the tail dorsally; it curves ventrally around the tip of the tail. The larvae have what appears to be a gill slit, called the gill spiraculum--a small chamber that encompasses the area where three gills are attached. There is a lateral line on both sides of the head and neck that serves as a sense organ for water movements.Please note that the map we provide only covers distributions in China, but they also occur in Vietnam.

The range encompasses parts of China [Yingjiang, Xishuang Banna (Jinghong, Mengla), southern Yunnan; southern Guangxi and southern Guangdong)] as well as Vietnam.

This species has an aquatic larval stage and a terrestrial adult phase. The adults Inhabit loose soil along small mountain streams with abundant plant cover, also seen along moist shores beside pools or rice-fields. During April to May females deposit about 30 eggs in a depression they dig close to water. Soon after hatching, the larvae make their way into the water where they feed on algae or plankton. Later in their development, they feed on aquaticinvertebrates. Metamorphosis is completed at a total length of 180mm. In captivity adults feed exclusively on earthworms.

Populations appear to be at high risk as they have declined rather quickly because of human activities including cultivationof the land, destruction of forest, and pollution, but there is little published data available to support these hypotheses.

The Banna caecilian, Ichthyophis bannanicus, is one of 44 species in the Asian caecilian genus Ichthyophis, (which, as per Nishikawa, Matsui and Yambun 2012 and Nishikawa et al. 2012 includes taxa previously contained in Caudacaecilia).This species is widespread in southeast Asia at altitudes of 100-600 m asl.It occurs commonly in Southern China, northern Vietnam, Laos, northeastern Thailand, and also thought to exist in Myanmar (Zigang et al. 2004; Nishikawa, Matsui and Orlov 2012; Frost 2016). The secret, underground life of Ichthyophis bannanicus and other caecelians means they are not often encountered, and little is known about their relationships and populations. Recent molecular analysis has shown that caecilians from southern Vietnam previously believed to be I. bannanicus are actually a newly described species, Ichthyophis nguyenorum (Nishikawa, Matsui and Orlov, 2012).Genetic barcoding techniques revealed several new Ichthyophis species in 2015, and brought the known number in Indochina (Cambodia, Laos, and Vietnam) from five to eight (Greiger et al. 2015).

Adult Banna caecelians are terrestrial and spend their time digging in moist, loose dirt near small forested streams, eating earthworms.They sometimes come out in vegetated parts along the edges of pools. They measure 32-38 cm in length, and have tiny eyes buried under the skin, and a sensory tentacle near each eye. Banna caecelians are brownish-black above, with a yellow stripe running laterally along each side of its body (Wang 1999). There are two types of coloration pattern in Ichthyophis: striped and not striped. While this characteristic has been shown to have no utility in classifying caecilians, it is useful for identification (Nishikawa, Matsui and Orlov, 2012).

During April to May females dig a shallow hole near water in which they lay about 30 eggs.The larvae are fully aquatic and feed on algae or plankton when small, later eating aquatic invertebrates. They have gills and a short tail with a fin that extends dorsally and around the ventral side of the tail.They use a lateral line on the sides of their head to sense water movement (Wang 1999).

Banna caecilians are found in disturbed habitats and cultivated fields, and the IUCN lists them as adaptable, widespread and “of least concern” for extinction (Zhigang et al. 2004).Wang (1999) however, suggests that populations have declined and are at high risk due to deforestation, pollution, and human activity.

Specimen of Ichthyophis bannanicus in National Museum of Natural Science in Taiwan

The Koh Tao Island caecilian (Ichthyophis kohtaoensis) is a species of amphibian in the family Ichthyophiidae found in Cambodia, Laos, Myanmar, Thailand, and Vietnam. Also known as the Ichthyophis bannanicus, the Banna caecilian, it is also found in southern China.

Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical moist montane forests, rivers, intermittent rivers, swamps, freshwater marshes, intermittent freshwater marshes, plantations, rural gardens, urban areas, heavily degraded former forests, irrigated land, and seasonally flooded agricultural land. It is threatened by habitat loss.

The scientific name refers to Ko Tao Island in the Gulf of Siam, where the type specimen was collected.