Palamnaeus: Indian scorpion
Class Arachinda of phylum Arthropoda includes such well-known and common forms as scorpions, mites and ticks. These are well dadepted for terrestrial life.
The scorpion àre readily recognized by their elongated body with a flexible tail terminating by their elongated body with a flexible tail terminating in a sharp poison sting. They are the oldest known terrestrial arthropods. They belong to the order scorpionida which includes 7 families,nearly 73 genera about 1,000 species. The, parabuthus, palamnaeus, scorpio, Hormurus Androctonus, etc. The following description of scorpion us generalized but mainly relates to the Indian genus Palamnaeus.
Habits and Habita
Scorpion are of wide occurrence but are largely restricted to tropical and subtropical areas of the world. They are especially abundant in deserts . They are fairly common in India , more abundant in deserts. They are fairly common in India, more abundant on the slopes of hills . They are solitary and secretive, hence rarely seen. They are largely nocturnal creatures. During day, they hide under stones, lg's, debris, old mattings, etc., in crevices or holes and underground in burrows. They become active at night when they come out of their dens to hunt and seek their prey. They are carnivorous and predaceous feeding chiefly upon spiders, also resort to cannibalism. They kill the struggling prey with their poisonous sting. Sexes are separate and during courtship , the male and female individuals seize each other's claws and perform a mating dance.
External Morphology
Habits and Habita
Scorpion are of wide occurrence but are largely restricted to tropical and subtropical areas of the world. They are especially abundant in deserts . They are fairly common in India , more abundant in deserts. They are fairly common in India, more abundant on the slopes of hills . They are solitary and secretive, hence rarely seen. They are largely nocturnal creatures. During day, they hide under stones, lg's, debris, old mattings, etc., in crevices or holes and underground in burrows. They become active at night when they come out of their dens to hunt and seek their prey. They are carnivorous and predaceous feeding chiefly upon spiders, also resort to cannibalism. They kill the struggling prey with their poisonous sting. Sexes are separate and during courtship , the male and female individuals seize each other's claws and perform a mating dance.
External Morphology
Shape and size. Body of scorpion is long , narrow, segmented and dorso-ventrally flattened. Size various from 3 to 8 cm in length. The smallest species is middle Eastern Microbuthus pusillus which is about 13 mm long . The largest indian species, palamnaeus swammerdami, grows to a length of about 15 cm, while Buthus tamulus, a common species, reach a length of nearly 8 cm.
Colouration. Colour various from shining bblack (in species infesting the tropical forests) to pale yellow (in form living in sand). Dorsal surface is usually darker than the ventral surface
Body divisions. Bodu is covered with chitinous exoskeleton. It is made of 18 segments which are divided into two main regions: (1) a short anterior prosoma or cephalothorax, and (2) a long posterior opisthosona or abdomen enduen in a stinging apparatus.
Prosoma. Anterior prosoma or cephalothorax is broad and formed by the fusion of head with thorax. It's segmented character is indicated by the presence of 6 pairs of appendages on the ventral side. These include small chelate chelicerae, large pedipalpi and 4 pairs of walking legs. Dorsally prosoma remains covered by a single m, large , four-sided chitinous plate or carapace. It's anterior margin is divided into two frontal lobes by a median notch. Carapace bear a pair of conspicuous simple median eyes, each raised on a small tubercle and closely placed together in the middle . In addition , 2 to 5 pairs of smaller lateral eyes are present along the antero-lateral margins of carapace. Besides appendages, the ventral surface of prosoma also bear a single , small, narrow and usually triangular plate, the sternum, between the coxae of third and fourth pairs of legs.
Colouration. Colour various from shining bblack (in species infesting the tropical forests) to pale yellow (in form living in sand). Dorsal surface is usually darker than the ventral surface
Body divisions. Bodu is covered with chitinous exoskeleton. It is made of 18 segments which are divided into two main regions: (1) a short anterior prosoma or cephalothorax, and (2) a long posterior opisthosona or abdomen enduen in a stinging apparatus.
Prosoma. Anterior prosoma or cephalothorax is broad and formed by the fusion of head with thorax. It's segmented character is indicated by the presence of 6 pairs of appendages on the ventral side. These include small chelate chelicerae, large pedipalpi and 4 pairs of walking legs. Dorsally prosoma remains covered by a single m, large , four-sided chitinous plate or carapace. It's anterior margin is divided into two frontal lobes by a median notch. Carapace bear a pair of conspicuous simple median eyes, each raised on a small tubercle and closely placed together in the middle . In addition , 2 to 5 pairs of smaller lateral eyes are present along the antero-lateral margins of carapace. Besides appendages, the ventral surface of prosoma also bear a single , small, narrow and usually triangular plate, the sternum, between the coxae of third and fourth pairs of legs.
Opisthosoma. Posterior plopisthoma or abdomen is long and natnar. It is made of 12 distinct segments and is further differentiated into two parts:(1)an anterior broad preabdomen or mesosoma, and(2) a posterior narrow postabdomen or metasomatism.
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