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[edit] Araneae

[edit] Introduction

Jean Baptiste -De Monet, Chevalier De Lamarck, the great French philosophical biologist, named the group Arachnida in 1815, when he divided Linne's heterogeneous group, Insecta, into three classes. The chief external features of Arachnida are the division of the body into two parts ¬properly called the prosoma and the opisthosoma The prosoma is composed of a united head and thorax, commonly known as the cephalothorax, and the opithosoma is also called the abdomen. Th~ prosoma of Arachnida is made up of nine segments, sometimes all of them are fused to form a dorsal carapace upon which the eyes are situated. In contrast to this comparative uniformity of the prosoma, there is much greater diversity in appearance of the opisthosoma and of its appendages. It m,ay wholly retain the segmented form or may be unsegmented, and mayor may not have several pairs of appendages.

An interesting problem afforded by the Arachnida is that of their evolutionary history. The puzzle is a dual one, the earlier question is the origin of the Aracllnida as a class, and the later one is their division into the different orders. The geological records are as follows: The primitive form which can be classed as Arachnida, the Eurypterida, are wholly palaeozoic, their earlier form are found in the upper Cambrian and latter in the Devonian. The most ancient of living forms, the S•corpions, are found in the Silurian. Spiders and Pedipalpi occur in the Carboniferous and all the principal orders of modem Arachnida are present in the Tertiary strata

A problem is the origin of the Eurypterida during the Cambrian era. According to classical or traditional theory by Lankester• and Pocock, the possible ancestor of the Eurypterida is to be sought among the Trilobites, the dominant organism of the Cambrian. Brief characters of these are given as follows :

Araneae: Abdomen jointed with the cephalothorax by narrow pedicel. Abdomen provided with spinnerets. Opiliones: Harvestmen-spider-like body; pedipals small, not chelate; chelicera not bearing spinnerets; two median eyes provided with tubercles, present on cephalothorax.

Pseudoscorpionida: One or two pairs of lateral eyes present on cepbalothorax; chelicera bearing spinnerets; pedipalpi large and chelate; body scorpion-like. Pedipalpida: Large to medium in body size; caudal appendage long,short or absent; first pair of legs long and modified into feelers, each provided with a rounded tip inserted of claws.

Scorpionida: Abdomen with a broad tail-like prolongation terminating in a poisonous sting; pectines always present on the underside of the base ofabdomen; pedipalp stout and chelate.

Solpugida: Chelicera enormous in comparison to body size; racquet organ present on the underside the last p"air of legs; pedipapls leg-like without claws; abdomen may have narrow prolongation but never provided with sting.

Xiphosura: Opisthosoma hexagonal, broadly pointed to prosoma; chelicerae of three segments, small and chelate; peripalpi not different from ambulatory legs. [King crab (Lim"'"s) has been used by the americans as food for both pigs and poultry, and in some areas it is believed that this food makes the hens lay more eggs. It is also reponed that film industry developed from the carapace of king crab].

Microthelyphonida: Minute in body size; caudal appendages long and many-segmented; fIrSt pair of legs long but not modified as feelers and each bears claws at the tip.

Richinulei: Cephalothorax provided with movable hood (cucullus) in front; eyes absent; third pair of legs in males modified as copulatory organs.

Acari: Mouth parts contained in a discrete anterior gnathosoma; portion of the ~yon which the legs are inserted (the podosoma) broadly joined to the portion of the body behind the legs (the opisthosoma) to form the idiosoma.

For the Orders Solpugida, Pedipalpida, Opilionida, Pseudoscorpionida, X iphosura, Microthelyphonida, Richinulei no subsequent comprehensive work has been published after the publication of the 'Fauna of British India' volume by Pocock (1900), where 25 species of pedipalps and 17 species ofsolifugids are recorded. Gravely (1910-1935) added to our knowledge of these animals to some extent. Tikader (1987) has enhanced our knowledge on ten orders of Arachnida in 'Handbook of Indian spiders'

Spiders are important components of life of India's vast and diversified•land. They are wide¬spread. found in all types of habitats and occupy all but a few niches. Spiders may be found near the edge of water-bodies, on the ground, in underground caves and on top of the mountains. In fact, jumping spiders have been collected even from Mount Everest region (22,000 feet), the highest elevation at which any animal has ever been found. It is recorded that ballooning spiders have been collected from air-planes at an elevation of 5000 feet. Some spiders like Pholcidae, Oecobidae, Heteropodidae and Filistatidae live inside human habitations, and others frequent the walls outside. Almost every plant has its spider fauna, as do the dead leaves on the forest floor.

They may be found under the bark. under stones, under fallen logs -these being only a few examples of their various habitats. There may be different species of spiders even in a small area, as for example nearly 600 species of spiders are known from Connecticut, a very small state of U.S.A. Some ground spiders like Geolycosa and trap-door spiders of the Western Ghats dig holes in the groun~ and remain there during their whole life, except for a shon period when the male ventures out to seek a mate.

The silk-lined tunnel of Atypus extends partly into the ground and partly along the surface of a tree. The wolf-spiders, mainly Lycosa and Hippasa may make use of shallow lobes in which they hide. Many spiders like Uloboridae, Pholcidae prefer dark and shady places, where the humidity is high. Some Pardosa and Lycosa species are found along the edge of streams and ponds, running over the water surface quickly, and in an emergency they can dive into water. Araneus and Tetragnatha species also prefer water sources 'but are usually found on the shrubs, which overhang the ponds or streams. Many crab-spiders like Thomisus and Misumena live among flowers, waiting in ambush for insect visitors. It was observed that crab-spiders change their colour according to that of the flowers. Tibellus, Thanatus and Oxyopes run along grasses; clubionids, salticids hunt on leaves.

Hersilid spiders live on walls of houses and on tree trunks. They are usually dark in colour, in resemblance to tree or wall on which they occur. The only social spider Stegodyphus sarasinorum Karsch, has attracted the attention of many naturalists in India. They built their nest in the foliage of Acacia arabica or Zizyphus sp. Many species are found on tall grass, on bushes and trees. Some run over the branches and trunk and hide under loose bark and in crevices.

Spiders have long been listed among animals that ~able to reproduce parthenogenetically. Afler laying a mass of eggs, the female covers them with a silken sheet and molds the mas into the egg sac characteristic of the species. The number of eggs laid by different spiders varies enormously. The essential work of the female is over as soon as eggs are laid and enclosed in some kind of silken sac. This act frequently represents the parental care. Spiders undergo a development within the egg that is comparable to that of other arachnids.

The embryo spider gradually takes form, outside vast sphere of yolk that makes up most of the egg. On the generalized part, which will become the cephalothorax, appear little buds and gradually become differentiated into the chelicerae, palpi and the legs. A ~imilar series appear on the abdominal portion. At rather defmite intervals in its development the spider casts off the bounds of its stiff ouler covering and eject itself for life in a more advanced stadium.

Currently Araneae have attracted the attention as a source of homeopathic as well as allopathic medicines. There are several species from which venom is extracted. Spider venom is the source of several drugs.

Spiders are often confused with insects. However, these can be easily diagnosed and separated from insects on the following characters :

1) Body divided into two unsegmented parts .. cephalothomx (or head) and abdomen.

2) Cephalothorax has four pairs of legs and a pair of six segmented pedipalps, modified in the male for spenn ttansportation.

3) Wings absent; eyes simple, two or eight in numbers.

4) Respiration by book lungs and genital pore on the ventral side near anterior end of abdomen.

5) Silk apparatus always present, opening at hind end of abdomen below anus.

6) Poison apparatus opening on fangs of chelicerae.

7) Development direct, spiderlings resemble their parents.

[edit] Historical Resume

Two of the earliest contributions on Indian spiders w.ere by Stoliczka (1868) and Karsch (1873) who reported many interesting species from Sri Lanka and Minicoy. Simon (1887-1906) recorded many species from the Himalaya, and Andaman and Nicobar•Islands. Thorell (1895) published a descriptive catalogue of about 200 species of Burmese spiders. Pocock (\900) recorded 200 species from India, Burma and Sri Lanka in the "Fauna of British India India, Arachnida" He concentrated mainly on the large-sized spiders available on the ground as well as orb ..webers. Sheriff (1919, 1929) and Reimoser (1938) described numerous interesting sPecies of spiders from southern India.

Caporico (1934-1935) described some species from Karakorum (Himalaya). Gravely (1912-1935) added considerably to the knowledge of Indian spiders, . particularly of families Lycosidae, Ctenidae, Clubionidae, etc. A number of species from Lahore were described by Dyal (1935). Narayan (1925) gave interesting accounts of many ant-like spiders of the family Salticidae. Contributions made by Sinha (1951-1952) on Lycosidae and Argiopidae may also be mentioned as important.

Recent studies on the families Thomisidae, Lycosidae, Gnaphosidae, Theridiidae, Scytodidae, Araneidae (= Argiopidae), Oonopidae, Clubionidae, Filistatidae, Uloboridae, Amaurobiidae, Die tynidae , Pholcidae, Salticidae, Linyphiidae, Tetragnathidae, Hersilidae, Oxyopidae, Pisauridae, Theraphosidae, Heteropodidae, etc. have been made by Tikader (1960-1987). Biswas (1987) worked on the spiders of Orissa reporting on the families Ararieidae, Gnaphosidae and Salticidae. Majumder and Tikader (in press) have studied clubionid spiders from India

Tikader and Gajbe (1973-1979) described many species of the Gnaphosidae and Platoridae. Gajbe (1981-1989) described many interesting species of Gnaphosidae from India, and Thomisidae Mimetidae, Oxyopidae, Uloboridae from Madhya Pradesh. Patel (1973-1989) worked on the spider fauna of Gujarat. Sadana (1973-1989) published some papers on the 'families Salticidae and Lycosidae from Punjab. Tikader and Biswas (1981) published an occasional paper on the spider fauna of Calcutta and its vicinity, and recorded 99 species under 47 genera of 15 families. Biswas (1982-1989) recorded many interesting species of the families Salticidae, Clubionidae and Gnaphosidae from West Bengal, Tikader (1980) under 'Fauna of India, Spider Part 1, Family:

Thomisidae'reported 117 s~ies under 25 genera of the family Thomisidae (crab-spider); Tikader. &Malhotra (1980) under 'Fauna of India, Spider Part 2' reported 97 species under 9 genera of the family Lycosidae (wolf spiders). Tikader (1982) under 'Fauna of India, Spiders Volume 2, part 1 and 2' reported 142 species under 21 genera of the family Araneidae and 110 species under 21 genera of the family Gnaphosidae. Tikader &Bal (1980-81) described many species of Araneidae and published an occasional paper on some orb-spiders. Tikader & Gajbe (1973-79) described many species of the family Gnaphosidae and Platoridae. GaJOe (1981-89) reported many species of the family Gnaphosidae from Madhya Pradesh and other parts of India. Patel (1973-1989) reported many species of different families from Gujarat. The karyological studies on some Indian spiders were investigated by Mittal (1976-1986).

[edit] Studies from Different Environs

The information on Indian terrestrial spiders is scattered. In the beginning, studies on these spiders were faunistically oriented. Extensive collections were made in the Himalayas starting from the Pir Panjal Range on the west to the Dafla Hil~, Khasi and Jaintia Hills and Sikkim in the easL Collections were also made from the peninsular India, especially from the Western Ghats. All the collections were studied by various arachnologists during the pre-independence period. These studies have culminated in the publication of one volume under the 'Fauna of British India' series. and a number of papers.

Araneae fauna collected by Zoological Survey of India has been extensively worked out in recent years from different parts of India: West Bengal, Assam, Arunachal Pradesh, Meghalaya. Gujarat, Maharashtra, Sikkim, Andaman-Nicobar Island and Orissa.

i) Fauna of Andaman and Nicobar Islands -The Araneae of Andaman and Nicobar Islands ecosystem have been described by various arachnologists such as Simon (1885), Thorell (1891) who published various papers on the Arachnid fauna of these islands. Recently, Tikader (1977) studied the spider fauna of Andaman and Nicobar Islands. His study was undertaken, with a view to describing the species occurring in these island and also comparing the distribution of spider fauna of these islands with those of the adjoining Indian mainland.

ii) Fauna of Sikkim -It was studied by Tikader (1970) which deals with the spiders from East Sikkim, West Sikkim and Northern part of West Bengal (between lat., 27.5 and 20.9 long. 87.S6 and 90.5) covering an area of about 7428 square kilometers. These areas are largely covered' bY' evergreen forests. The study is based on the collections made 'by B. K. Tikader, as a member of the Indo-Swiss Zoological Expedition, 1959. Altogather 65 species, contained in 33 genera, distributed in the families Uloboridae, Homalonychidae, Theridiidae, Linyphidae, Argiopidae, Thomisidae, Aglenidae, Hahniidae, Pisauridae, Lycosidae and Oxyopidae have been dealt in this paper. Of these, SO species are new to science.

iii) Araneae of Deccan area -One of the earliest fields of Stoliczka (1869) who reported many interesting species from Bombay, Madras and southern India. Sheriff (1927-1951) has described a number of interesting species, particularly from the Deccan. Grilvely (1921-1935) had contributed considerably to our knowledge of spiders of this region. Namyan (1915) had recorded the occUlTence of several remarkable fonns of ant-like spiders of Salticids in the Deccan area. Recent studies of Sinha (1951-1952) on the families Lycosidae and Argiopidae need also to be mentioned as important additions to our knowledge of Indian Arachnology. More recently, Tikader (1960-1967) has described 164 species of spiders from the Deccan, under the families Araneidae, Lycosidae, Clubionidae, A vicularldae, Heteropodidae, Sparassidae, Dictynidae, Dipluridae, Erigonidae, Filistidae, Oecobidae, Oxyopidae, etc.

iv) Fauna of Orissa -Biswas (1987) has described 29 species of spiders from Orissa under the families Araneidae, Gnaphosidae and Salticidae.

[edit] Estimation of Taxa

So far 104 families of spiders have been recognised from the world. Approximately, 35000 species of spiders have been named from the world, representing what is believed to about one fourth of the total number of species supposed to be present. A total of 1015 species belonging to 236 genera under 44 families are so far known from the Indiari subcontinent. The National Zoological collections of India comprise about 1250 speCies belonging to 43 families and collected from different localities of India and other countries.

[edit] Classified Treatment

The classification now generally followed by almost all archanologists of the world is based essentially on that proposed by Penttunkevitch (1928) in his Systema Aranearum. Among the very numerous monographs dealing with the comprehensive natural History of spiders in general. that of Walckenaer (1806-1837) may perhaps be considered as an extremely valuable contribution. Simon (1892-1897) did a monumental work on taxonomy of spiders.

It is a most valuable contribution towards the science of Arachnology of the world. Arachnologists are fortunate in having two major bibliographic work concerned with world spider fauna. One is Roewer's 'Katalog der Araneae' in which are listed in essential completeness the spider representation from the entire world. An even more ambitious and scholarly work is the "Bibliographia Araneaorum" of Pierre Bonnet of the Uiliversity of Toulouse in which are listed almost all spider representation from the entire world. From these sources and from supplementary catalogues, it has been possible to glean reasonably accurate information on the distribution of spider fauna of the world.

[edit] Current Studies

In the Hdqrs. of Zoological Survey of India, systematics and distribution of Araneae (spiders) of West Bengal are currently under study. Our knowledge is far from satisfactory and hence a revision of some families has been taken up. Studies on 20 families have been completed. Keys for the genera and species of these families have 3Iso been prepared.

At Central Regional Station, Jabalpur, the spiders of Madhya Pmdesh are under study. Revision of some families like Thomisidae, Araneidae, Lycosidae, Gnaphosidae have been completed and of some other families like Oxyopidae is taken up.

Outside Z.S.1. no serious research on spiders is carried out. In a few universities, namely, Bhavnagar University, Bhavnagar; Panjab University, Chandigarh. Punjab Agricultural University, Ludhiana etc., studies on spiders are being conducted. These studies are aimed at taxonomy, ecology and karyology.

[edit] Expertise India

[edit] In ZSI

U. A. Gajbe, Zoological Survey of India, Central Regional Station, Napier Town, Jabalpur, (Madhya Pradesh).

Bijan Biswas, S. C. Majumder &Kajal Biswas, all of Zoological Survey of India, M-Block, New Alipore, Calcutta -700 053.

[edit] Elsewhere

B. K. Tikader, Salt Lake City, C. L. 85, Calcutta.

B. H. Patel, Dept. of Zoology, P. P. Institute of Science, Bhavnagar, (Gujarat).

G. L. Sadana, Dept. of Zoology, Panjab Agricultural University, Ludhiana -141 004. (Punjab).

O. P. Mittal, Dept. of Zoology, Punjab University, Chandigarh 160 014.

[edit] Abroad

A. R. Brady, Biology Dept, Hope College, Holland Michigan 49423 (U.S.A.).

C. Deltschev, Institute of Zoology, Bulgarian Academy of Science, Rusky 1. Sofia -1000. (Bulgaria).

C. D. Dondale, Biosystematics Research Institute, Research branch Agriculture, Ottawa. Ontario, KIO 006 (Canada).

R. R. Jacson, Dept. of Zoology, University of Canterbury, Private Bag, Christchurh. (New Zealand).

R. R. Forstar, Otago Museum, Great King Street, Dunedin (New Zealand).

T. Yaginuma, Biological Laboratory, Ohtemon-Cakuin University. 2-1-15 Nishi-Ai. Ibaraki, Osaka 567 (Japan).

H. W. Levi, Museum of Comparative Zoology, Harvard University, Cambridge, Mass. 02138 (U.S.A.).

N. I. Platnick, Dept. of Entomology, Central Park, West at 79th Street, New York, Ny 100 024 (U.S.A.).

J. Proszynki, Prusa 12.08-110 Siedlee, (poland).

V. D. Roth, Southwestern Research Station, Box 136. Ponal, Arizona 85632 (U.S.A.).

Song Daxiang, Dept. of Invertebrate Zoology, Institute of Zoology, Academia Sinica, 100 080, Beijing (China).

P. T. Lehtinen, Zoological Museum, University of Turko, 20500 Turku 50. (Finland).

M. Vachon, M. N. H. N. Laboratoire des Arthropodes, 61 rue de Buffon, 75005 Paris. {Fmnce).

B~ D. Open, Dept. of Biology, Virginia State University, Blacksburg, Virginia 24061 (U.S.A.). .

F. R. Wanless, Dept dfZoology, British Museum (Natural History), Cromwell Road, London SW7 5BD (U.K.).

[edit] Selected References

Biswas, B. 1987. Araneae -Spiders (Families: Araneidae, Gnaphosidae and Salticidae). Fauna of Orissa: Statt Fauna Sereis No.1, Part 1 : 257-272. Gravely, F. H. 1931. Some Indian spiders of the 'families Ctenidae, Sparassidae, Selenopidae and

Clubionidae. Rec.lndian Mus., 33 : 211-281. Pocock, R. I. 1900. Fauna ofBritish India, Arachnida, : 1-279. Tikader, B. K. 1970. Spider fauna of Sikkim. Rec. zool. Surv. India, 63 : 1-83. Tikader, B. K. 1977. Studies on spider fauna of Andaman &Nicobar Islands, Indian Ocean. Rec.

zool. Surv. India, 72 : 153-212. Tikader9 B. K. &Malhotra, M. S. 1980. Fauna ofIndia, Spiders: Araneae (Families: Thomisidae &Lycosidae), Vol 1 : 1-446. Tikader, B. K. &. Biswas B. 1981. Spider fauna of Calcutta and vicinity. Rec. zool. Surv. India, Occ. pap. No. 30 : 1-149. Tikader, B. K. 1982. Fauna ofIndia, Spiders: Araneae, (Families: Araneidae &Gnaphosidae) Vol. 2 (1-2) : 1-536. Tikader, B. K. 1987. Handbook: Indian Spiders. Z.S.I.t Calcutta: 1-251.