Myriapoda: India
Contents |
Faunal Diversity in India: Myriapoda
This is an extract from FAUNAL DIVERSITY IN INDIA Edited by J. R. B. Alfred A. K. Das A. K. Sanyal. ENVIS Centre, Zoological Survey of India, Calcutta. 1998 ( J. R. B. Alfred was Director, Zoological Survey of India) |
Introduction
The myriapods are wormlike (Myriads= numberless; pedes= feet), multisegmented, multilegged and tracheate (i.e., air breathing through trachea) terrestrial arthropods which on the basis of segmentation of their body and possession of number of pair of legs per segment are divided into four classes, viz., Chilopoda, Diplopoda, Pauropoda and Symphyla. While Chilopods are opisthogoneate (i.e., genital duct opening posteriorly), the remaining three classes of myriapods are progoneate (i.e., genital duct opening in the anteriorpody segments).
All the four classes were formerly included under a single super class Myriapoda on the basis of their possessing many legs and body having two major subdivisions, the head and the trunk; but they are now recognised as' widely divergent phylogenetically so as to merit them ranking under separate classes.
The Chilopods are the group of multilegged anil1ldl-which bear one pair of leg per segment and are commonly known as "centipedes' Diplopods, however, have two pairs of legs per segment, presumably formed by the fusion of two segments during the process of evolution. The class Diplopoda is divided into two subclasses, viz., Chilognatha and Pselognatha, the former having six orders of all living diplopods, comprising twenty families and the latter having one order and one family. It may be pertinent to mention here that the members of the class Diplopoda are known as "millipedes." The class Chilopoda is divisible into two subclasses, viz., Epimorpha (i.e., body segments complete at the time of hatching) and Anamorpha (i.e., body segments complete only after hatching).
Until recently, four orders of the class Chilopoda were known, viz., Scolopendromorpha, Geophilomorpha, Lithobiomorpha and Scutigeromorpha. Shear and Bonamo (1988) have recently described Devanobiomorpha, a fifth and a new order of fossil Centipedes from Middle Devonian (Cat Skill Delta) sediments, near Gilboa, New York, U.S.A. and assigned it as a sister group of the orders Scolopendromorpha+ Geophilomorpha (= Epimorpha). Though Myriapoda is a very large group of land arthropods, with a number of species under each class and order, yet no comprehensive account of species diversity is available in India. Of late, the most well worked out group under this category of animals is the Order Scolopendromorpha, and hence the status report on the biodiversity conservation is restricted here to the Order Scolopendromorpha only.
Status Of The Taxon
Global and Indian Status
The Scolopendrid centipedes are known globally by about six hundred odd species, of which India alone supports roughly 15-18% species, as per available information. The order Scolopendromorpha contains seventeen genera under family Scolopendridae and eight genera under Cryptopidae, but in India, we have the representation of seven genera of family Scolopendridae (i.e., about 40%) and two genera of the family Cryptopidae (i.e., 25%). Roughly about 15-25% of the present number, so far as the order Scolopendromorpha is concerned, needs to be discovered. A good number of species remains to be identified ~d placed on record for the centipedes of the order Geophilomorpha. Lithobiomorpha and Scutigeromorpha under class Chilopoda and whole of the group of class Diplopoda is unknown till date.
Distribution
Distribution of centepeds in different regions of India is shown in Table 1~ Faunal Diversity in India Table-l Distribution of Centepedes in India Region No. of Species
Biological Diversity And Its Special Features
The Order Scolopendromorpha is further subdivided into two families, viz., Scolopendridae, the members of which have four ocelli on each side of the cephalic plate, below the base of antennae and Cryptopidae, whose members are blind and mostly cavemicolous. While majority of the species are classified as Oriental element, only a small percentage of Indian species comprise Palaearctic, Nearctic, Ethiopian, Circumtropical and Cosmopolitan elements.
Endemic And Threatened Species
Under the Oriental element (92 species/83%), roughly 60 species (65%) are endemic to India and neighbouring countries like Pakistan, Bangladesh, Nepal and Srilanka. Only a very small percentage of Oriental element represents the Indo-Malayan (14%) or Indo-Malayan extending to Australian region (3%).
None of the species can, at present, be categorised as endangered but species like Scolopendra hardwicki, S. slIbspinipes and Ethmostigmlls pygomegas are extremely rare and can be threatened by the continuous degradation and destruction of their habitats.
Introduced Species
Since the myriapods are soil arthropods, always associated with nursery plants, agricultural crops and vegetables, the chances of their being transported/introduced from outside, can not be ruled out. The species of the genus Digitipes is of congo origin and recorded from Deccan only. This is probably one of the examples of introduced species since it has not established elsewhere in India. Similarly many of the species described/ recorded are based on solitary specimen, which raises doubts about their establishment in India.
Value
The scolopendrid centipedes are of economic importance, despite the fact that they are poisonous and their bite is not only painful but causes diseases like Oedaema, Lymphangites with inflammation of skins and subcutaneous tissues or ulceration. In most cases, a localised necrosis may also take place or sometimes even death is reported, if it bites an infant. At the same time, they are beneficial also on account of these being predators on many species of pest of crops. While millipedes cause damage to the crops only under forced conditions of drought, both centipedes and millipedes have a definite role in soil fertility, like earthworms, by ingesting the humus followed by defaecation, with more nitrogen contents returned in purified form to the soil. They also help in the decomposition and disintegration of humus for the fertility of soil. Humanity should definitely be concerned about preserving this taxon, primarily for its faunal value, secondly for its economic, agricultural and medicinal value and thirdly, for much more is yet to be known about this creature.
Threats
With ever increasing human population, ever growing industrial development, deforestation and other factors like habitat destruction, the depletion of the fauna and faunal resources including myripods is inevitable. Faunal Diversity in India
Conservation Strategies And Future Action
Let the forests be for the wild and wilderness for the creatures of nature to strive in their serenity. Though no measure seems to have been taken in the past, with specific purpose in mind, to protect this taxon, environmentalist's movement in the direction of afforestation and conservation of fauna and faunal resources should be taken up more seriously by one and all. More and more conservation areas should be identified for protection and biodiversity conservation by declaring these as National Parks and Biosphere Reserves.
Selected References
Ahmed, S. 1980. On a collection of centipedes (Scolopendromorpha : Scolopendridae and Cryptopidae) from Andaman and Nicobar Islands. Rec. zool. Sum India., 77: 25-30.
Attems, C. 1930. Scolopendromorpha. Das Tierr., 54 (2) : 1-308. Gravely, F. H. 1910. The distribution of Oriental Scolopendridae. Rec. Indian Mus., 5 (1) : 161-172. Jangi, B. S. and Dass C. M. S. 1984. Scolopendridae of Deccan. J. Scient. indo Res., 43: 27-54.
Khanna, V. 1977. Studies on the centipede genus Trachycormocephalus (Myriapoda: Scolopendridae) from Rajasthan, India. Orient. Ins., 11 (1) : 151-156. Khanna, V. 1991. Chilopoda. Animal Resources of India: Protozoa to Mammalia. State of the Art Report, Zoology, (ZS1) (Publ.): 461-465.
Shear, William A. and Bonamo. P. M. 1988. Devanobiomorpha, a new order of centipedes (Chilopoda) from middle Devonian of Gilboa, New York State, USA., and the phylogeny of centipede orders. Amer. Mus. nat. Hist., Novitates. 2927: 1-30.
