ON A COLLECTION OF SOIL PROSTIGMATID MITES ( ACARI ) FROM SOUTHERN PARTS OF WEST BENGAL , INDIA

Mites form very important biotic component in soil, litter, mosses and lichens. Any sample from these environs will reveal the occurrence of a large number of species. These are important not only because of the fact that they help in biodegradation of soil organic matter and enrich fertility but also help in recycling of soil nutrients and help in dispersal of soil fungi which, in turn, help in biodegradation process. Many of the soil prostigmatid mites are useful predators of soil insects and nematodes. Among the soil mites, the prostigmatid mite fauna of India has not been properly explored as evident from the fact that only 26 spp. under 16 genera and 7 families are so far known from soil, of those 11 spp. under 4 genera and 2 families are known from West Bengal (in Prasad, 1974; Gupta, 1991).


INTRODUCTION
Mites form very important biotic component in soil, litter, mosses and lichens.Any sample from these environs will reveal the occurrence of a large number of species.These are important not only because of the fact that they help in biodegradation of soil organic matter and enrich fertility but also help in recycling of soil nutrients and help in dispersal of soil fungi which, in turn, help in biodegradation process.Many of the soil prostigmatid mites are useful predators of soil insects and nematodes.Among the soil mites, the prostigmatid mite fauna of India has not been properly explored as evident from the fact that only 26 spp.under 16 genera and 7 families are so far known from soil, of those 11 spp.under 4 genera and 2 families are known from West Bengal (in Prasad, 1974;Gupta, 1991).This indicates that there is a vast scope to explore prostigmatd mite fauna from soil and indepth taxonomic study will reveal many interesting and hitherto unrecorded species.While in other orders like Cryptostigmata over 500 spp.(Sanyal, 1991) and Mesostigmata 156 spp.(Bhattacharya et at., 1996) are known from India.
Because of being highly fragile, soft bodied, and colourless bodies of these mites, these mites are often ignored during the process of sorting of soil extracted mite specimens considering these as immature stages, although it is a fact that this habitat is highly rich with the prostigmatid mite fauna.
Cosidering the inadequacy of knowledge in this group of mites, the authors carried out survey of these mites in West Bengal during 2003-2005 and results thereof are presented in this paper.

MATERIAL AND METHODS
The mite specimens studied in this paper were collected from soil samples taken from Howrah, Hooghly, 24-Parganas (N), 24-Parganas (S), East Medinipur and West Medinipur districts of West Bengal.The samples were extracted by using the standard method of extraction with the Tullgren funnel apparatus.The identified specimens are deposited in the National Zoological Collection, Zoological Survey of India, Kolkata.

Remarks:
This was described basing on collection made on Gossypium sp. in Mozambique and therefore its record on leaf litter is a new habitat record.

Pronematus sp.
Collection Records One male; village area, Bargachia, Howrah, West Bengal;from soil;22.ix.2003.Remarks : The specimen was in badly damaged condition and hence specific detennination could not be done.

Remarks:
The specimen was damaged during the process of extraction of soil litter sample and therefore further identification was not possible.
Remarks: Baker (1965) described a species Triophtydeus alaskansis collected on Salex sp, in quarantine.The occurrence of this species in soil is therefore a record of new habitat.
Remarks : Normally, the specimens of this genus are inhabitants of moss.However, in the present case it was collected from soil and therefore it is a new habitat record.

Remarks:
The members of this genus occur in bark, litter, leaf etc. From India three species are known (Gupta, 2002) but the present one differs from all the known species in dorsal chaetotactic pattern.Final decision regarding identification will be taken after studying further material.

Remarks:
The members of this genus are inhabitants of soil, litter, pine cone, leaves, etc.The present specimen collected from soil is being recorded here for the first time in India and no member of this genus was earlier reported from India.

Remarks:
The members of this genus occur in soil rich, in organic matter, tree hole, litter, etc. (Smiley, 1992) and earlier this genus was not recorded from India.Final decision regarding identity wiIl be taken after further study and collection of additional material.Remarks: So far only four species of this genus are known from India (Gupta, 2002).The specimen collected in the present case did not tally with any of those.Further examination is on with the collection of additional material and the result thereof will be published elsewhere.
Remarks: This genus was so far not reported from India.The present species appears to be a new one which will be described elsewhere.Remarks: This mite species is more common in storage habitats and has also has been recorded on tree trunk, leaf (Gupta, 2002).Therefore is occurrence in soil is interesting.

22.ix.2003.
Remarks: This mite is known from habitats like paddy, guava, magnolia, debris, leg horn, skin of bird (Gupta, 2002) and is not known from habitat like soil.
Remarks: Earlier records of this species in India are from garlic, in association with Aceria tulipae and paddy in association with paddy.Therefore, soil is the new habitat of this species.Collection Records: One male; guava garden, Bamungachi, Baruipur, 24-Parganas (South), West Bengal; from soil; 20.ix.2004.

Remarks:
The earlier record of this species is from debris in Madhya Pradesh and hence soil is the new habitat of this species and is reported here for the first time from West Bengal.
Family S. T ARSONEMIDAE Kramer 20.Tarsonemus sp.Remarks: A very interesting species of this genus was collected from soil which does not tally with any of the known species of this genus.The family and the genus were previously unknown from India.The material is under study and final decision regarding its identity will be taken with the availability of further material.
Heyer (1979)ecords: One male; Chowkisole forest ofRamgarh, Goaltore, West Medinipur, West   Bengal; from soil; 23.iii.2005.The specimen of this genus are habitants of mosses and lichens and soil therefore is a new habitat record.The present specimen is very close to C. setirostris in having almost similar palpal chaetotaxy but the spines on genu and tibiotarsus are relatively smaller.Inadequate material did not allow further identification.10.Cunaxa sp.Dr.carinaDen Heyer Remarks : DenHeyer (1979)collected Cunaxa carina from litter in South Africa.The present specimen also collected from litter is close to C. carina but final decision regarding identity could not be taken pending study of further material.