The Story of a Caecilian Species-Bombay Ichthyophis
(Ichthyophis bombayensis)
Dr. Raju Vyas
Dr. Raju Vyas
(Ichthyophis bombayensis; Photo: Dr Raju Vyas)
The caecilians, specifically known as legless amphibians, constitute a lesser known group of amphibians. They are distributed in many parts of the world. As per the amphibian database as on October 8, 2008, the class amphibians contain 6,398 species, out of which, there are 176 species of Gymnophiona (caecilians). Twenty nine species of caecilians are found in India.
In the evening on 18th July, 1998, a young wildlife researcher, equipped with a pair of binoculars and field guides, was walking slowly and cautiously in search of mammalian and avian wildlife along his transect parallel to a river flowing through a forest in South Gujarat. Though he was tired due to his day-long field survey in the jungle, he still had a single-minded interest; i.e., to catch a glimpse of crepuscular wildlife. Suddenly, near Sadad-devi village, he saw an unusual, 10-15 cm long snakelike creature on the wet forest floor that was adjacent to the river (a lotic wetland in the forest). It was a badly injured animal as its head was pressed or stapled. Hence, the animal was struggling on the way to its death. As the researcher, Dr. Ketan Tatu, was not a herpetologist, he collected the creature for proper identification with the help of other senior herpetologists in the team, i.e., Dr. B. H. Patel and I.
Dr. B. H. Patel identified it as a caecilian specimen. The caecilians are the legless amphibia belonging to Apoda order. It was further identified as Ichthyophis bombayensis species. Most probably this was the first authentic specimen of the I. bombayensis from the type locality area after the description the species.
The history of I. bombayensis species shows that Mr. F. Gleadow had obtained a 390 mm long caecilian from the then Waghai, Surat district (today’s Dangs district of Gujarat State), Bombay Province in 1888. The specimen was deposited in the then British Museum (Natural History) [today’s ‘The Natural History Museum, London’, BMNH No. 1888.6.11.1]. Further the specimen was carefully examined by E. H. Taylor (1960) and was described as a new species of a caecilian as Ichthyophis bombayensis.
In the evening on 18th July, 1998, a young wildlife researcher, equipped with a pair of binoculars and field guides, was walking slowly and cautiously in search of mammalian and avian wildlife along his transect parallel to a river flowing through a forest in South Gujarat. Though he was tired due to his day-long field survey in the jungle, he still had a single-minded interest; i.e., to catch a glimpse of crepuscular wildlife. Suddenly, near Sadad-devi village, he saw an unusual, 10-15 cm long snakelike creature on the wet forest floor that was adjacent to the river (a lotic wetland in the forest). It was a badly injured animal as its head was pressed or stapled. Hence, the animal was struggling on the way to its death. As the researcher, Dr. Ketan Tatu, was not a herpetologist, he collected the creature for proper identification with the help of other senior herpetologists in the team, i.e., Dr. B. H. Patel and I.
Dr. B. H. Patel identified it as a caecilian specimen. The caecilians are the legless amphibia belonging to Apoda order. It was further identified as Ichthyophis bombayensis species. Most probably this was the first authentic specimen of the I. bombayensis from the type locality area after the description the species.
The history of I. bombayensis species shows that Mr. F. Gleadow had obtained a 390 mm long caecilian from the then Waghai, Surat district (today’s Dangs district of Gujarat State), Bombay Province in 1888. The specimen was deposited in the then British Museum (Natural History) [today’s ‘The Natural History Museum, London’, BMNH No. 1888.6.11.1]. Further the specimen was carefully examined by E. H. Taylor (1960) and was described as a new species of a caecilian as Ichthyophis bombayensis.
The Study Area and the Location of the Protected Area
The species was then described on the basis of a single type specimen. Its validity has been accepted by almost all the herpetologists. A scientist of Zoological Survey of India (ZSI), Dr. R. S. Pillai recorded the second specimen of the species from Sringeri, Karnataka (Pillai & Ravichandran, 1999). One more specimen of the species was collected from Sringeri, Karnataka by Dr. S. V. Krishnamurthy. But both the specimens were collected from the sites that were 1000 km (approximately) from the type locality. Thus, the species had been recognized with the help of three specimens up to year 2003. The records of the species from Karnataka State require further conformation. Recently published ‘Hand-Book of Indian Amphibians’ by a Senior Scientist of Zoological Survey of India, Dr. S. K. Chanda has expressed his opinion on the species that "No information is available on the natural history of the species, which is known only from type. Status and distributional survey of the species are urgently required to know the conservation status of the species". Unfortunately, once the species was described, there was no subsequent information regarding the species and no one made any attempts to study or survey the area from where the initial (‘original’) specimen was obtained in 1888.
Therefore, a survey was necessary in the area from where the type specimen was collected 115 years ago. Today, the area of Waghai, Dangs district of Gujarat state is located in the two important Protected Areas and in some of the reserved forests.
Before the identification of the Sadad Devi specimen in Vansda, Gujarat by Dr. B.H. Patel and I, I had received a few coloured photographs of an unusual creature from Mr. Snehal Patel (President, Nature Club, Surat) for identification in 1994. This creature looked like a giant earthworm. It was found during the nature education camp at Dhuladha, Dangs.
Therefore, a survey was necessary in the area from where the type specimen was collected 115 years ago. Today, the area of Waghai, Dangs district of Gujarat state is located in the two important Protected Areas and in some of the reserved forests.
Before the identification of the Sadad Devi specimen in Vansda, Gujarat by Dr. B.H. Patel and I, I had received a few coloured photographs of an unusual creature from Mr. Snehal Patel (President, Nature Club, Surat) for identification in 1994. This creature looked like a giant earthworm. It was found during the nature education camp at Dhuladha, Dangs.
Ichthyophis-a legless amphibian (caecilian)
The injured-dead specimen in the vicinity of a lotic wetland near Sadad Devi village, Vansda and photographs of unidentified creature of Dhuladha, Dangs gave me a special inspiration and temptation for conducting further study on the species. Most of caecilians species are known from one or two specimens and the available literature categorize them as rare amphibians. Therefore, I made a further detailed study on the species with the help of GEER Foundation, Gandhinagar and DAPTF Seeds Grants, UK.
The type locality of the species “Waghai, Dangs” area is situated in the northernmost end of the Western Ghats in Gujarat State, i.e. the area between Surat (southern part of the district from the river Tapi) and Valsad districts (between the latitude 21° 12' N - 20° 12' N). It covers an area of about 14,655 sq. km including two very important Protected Areas, namely, Vansda National Park and Purna Wildlife Sanctuary.
A survey was conducted in the northern most ends of the Western Ghats, especially in two protected areas, namely, Vansda National Park and Purna Wildlife Sanctuary, Gujarat State, during the five years from 1998 to 2002.
Total 26 specimens of various age groups of the species (Ichthyophis bombayensis) could be examined, including 7 dead and 19 live specimens (range of size = 180- 542 mm; average size= 364; n= 19) [including a specimen examined on the basis of its coloured photographs].
This caecilian species prefer some special type of micro-habitat. Most of the specimens (78.94 %) were found or dug-out from its retreat. Fifteen specimens of the species were dug out from loose soils deposited on the edges of river streams, especially from river pools indicating the importance of wetland habitat in the forested areas.
The distances of the availability of specimens from the river or river stream are:- Twenty specimens (76.92 %) of the species were found close (0 to 80 m) to river stream, where as six specimens (31.57 %) were found from the distances of 250 to 500 m from a river. These distances of specimen discovery show that the species inhabits riverine habitat in the forest and those found at far distances from the river streams are sighted only during the rainy days, except two specimens which were found dead on the road during the colder season. During summer the species congregates in perennial river pool banks and in monsoon indicating significance of wetland habitat for this species.
The study result shows that the species is relatively uncommon in the area and their specific habitats are limited in riverine forests of the Purna and the Ambika river systems only. An average of one per kilometer of single potential habitat patch (about 50 m) is usually found on river stretch in both the PAs. Total 70 km of Purna and Ambika river stretches pass through the PAs and about over 150 such kind of the potential habitat patches of the caecilian species are recorded (typical river pools in summer) in and around protected areas.
Present data shows that the Bombay Caecilian (Ichthyophis bombayensis) is the largest Indian caecilian. It is very patchily distributed in riverine/riparian forest of Dangs, Navsari and Surat districts of southern Gujarat State and the area is a part of northern most ends of Western Ghats.
This study on the distribution of the Bombay Caecilian (Ichthyophis bombayensis) species had drawn a special attention for other caecilian experts from the world and guided a special direction for new thinking. Is the species endemic to Gujarat State only? Or, is it also distributed in other parts of Western Ghats (considering a few reports of the species to be found in the forests of Karnataka State)? If yes, then whether or not the two populations different and not found in the between forest areas? The data on the specimens of I. bombayensis of various age groups in that study create a doubt about the validity of the other three earlier described species of caecilians; I. malabarensis, I. peninsularis and I. subterrestris. These can be clarified only by studying DNA sequences of the species.
The Indian herpetologists and taxonomists from various institutions met under the leadership of Dr. David J. Gower to know definite distribution range of I. bombayensis and to know whether or not the other three morphological similar species of unstriped ichthyophis are valid. The herpetologists of the various regions and DNA molecular collected sample tissues of these four species of caecilians inhabiting Dangs and from Surat to the tip of Kanyakumari, Tamil Nadu.
The results of DNA sequences indicated that the Bombay Caecilian (Ichthyophis bombayensis) is widely distributed in the Western Ghats, from dry deciduous forests of Surat, Dangs to the rain forests of Kanyakumari, Tamil Nadu. The species is under anthropogenic pressures and facing threats like habitat degradation, alteration and pollution. Some conservation measures are required.
The type locality of the species “Waghai, Dangs” area is situated in the northernmost end of the Western Ghats in Gujarat State, i.e. the area between Surat (southern part of the district from the river Tapi) and Valsad districts (between the latitude 21° 12' N - 20° 12' N). It covers an area of about 14,655 sq. km including two very important Protected Areas, namely, Vansda National Park and Purna Wildlife Sanctuary.
A survey was conducted in the northern most ends of the Western Ghats, especially in two protected areas, namely, Vansda National Park and Purna Wildlife Sanctuary, Gujarat State, during the five years from 1998 to 2002.
Total 26 specimens of various age groups of the species (Ichthyophis bombayensis) could be examined, including 7 dead and 19 live specimens (range of size = 180- 542 mm; average size= 364; n= 19) [including a specimen examined on the basis of its coloured photographs].
This caecilian species prefer some special type of micro-habitat. Most of the specimens (78.94 %) were found or dug-out from its retreat. Fifteen specimens of the species were dug out from loose soils deposited on the edges of river streams, especially from river pools indicating the importance of wetland habitat in the forested areas.
The distances of the availability of specimens from the river or river stream are:- Twenty specimens (76.92 %) of the species were found close (0 to 80 m) to river stream, where as six specimens (31.57 %) were found from the distances of 250 to 500 m from a river. These distances of specimen discovery show that the species inhabits riverine habitat in the forest and those found at far distances from the river streams are sighted only during the rainy days, except two specimens which were found dead on the road during the colder season. During summer the species congregates in perennial river pool banks and in monsoon indicating significance of wetland habitat for this species.
The study result shows that the species is relatively uncommon in the area and their specific habitats are limited in riverine forests of the Purna and the Ambika river systems only. An average of one per kilometer of single potential habitat patch (about 50 m) is usually found on river stretch in both the PAs. Total 70 km of Purna and Ambika river stretches pass through the PAs and about over 150 such kind of the potential habitat patches of the caecilian species are recorded (typical river pools in summer) in and around protected areas.
Present data shows that the Bombay Caecilian (Ichthyophis bombayensis) is the largest Indian caecilian. It is very patchily distributed in riverine/riparian forest of Dangs, Navsari and Surat districts of southern Gujarat State and the area is a part of northern most ends of Western Ghats.
This study on the distribution of the Bombay Caecilian (Ichthyophis bombayensis) species had drawn a special attention for other caecilian experts from the world and guided a special direction for new thinking. Is the species endemic to Gujarat State only? Or, is it also distributed in other parts of Western Ghats (considering a few reports of the species to be found in the forests of Karnataka State)? If yes, then whether or not the two populations different and not found in the between forest areas? The data on the specimens of I. bombayensis of various age groups in that study create a doubt about the validity of the other three earlier described species of caecilians; I. malabarensis, I. peninsularis and I. subterrestris. These can be clarified only by studying DNA sequences of the species.
The Indian herpetologists and taxonomists from various institutions met under the leadership of Dr. David J. Gower to know definite distribution range of I. bombayensis and to know whether or not the other three morphological similar species of unstriped ichthyophis are valid. The herpetologists of the various regions and DNA molecular collected sample tissues of these four species of caecilians inhabiting Dangs and from Surat to the tip of Kanyakumari, Tamil Nadu.
The results of DNA sequences indicated that the Bombay Caecilian (Ichthyophis bombayensis) is widely distributed in the Western Ghats, from dry deciduous forests of Surat, Dangs to the rain forests of Kanyakumari, Tamil Nadu. The species is under anthropogenic pressures and facing threats like habitat degradation, alteration and pollution. Some conservation measures are required.
