Morphological Study to the Form and Number of Eyes in Scorpions and Spiders

Abstract

Scorpions and Spiders belong to the class Arachnida in phylum Arthropoda. Scorpions are easily distinguished by median eyes  on obvious the center of the carapace and have one pair, and lateral eyes have 2-8 in some species Scorpions do not have good eyesight so the median eyes have always been simple and they are more sensitive than the lateral pairs; and have  anterior median eyes(AME) are narrow field of view and pairs of lateral eyes(LE) are more sensitivity and response to light family Buthidae have 2-6 lateral eyes in  Compsobuthus Mesobuthus, Hottentotta and  the family  Vaejovidae ,Chactidae and Chaerilidae have 2 pairs of lateral eyes. 3pairs in Orthochirus and  Androctonus  . Then Spiders have six eyes  in family  Pholicidae, Sicariidae , Araneidae, Salticidae, and  eight eyes in Theridiidae , Lycosidae   and some with two eyes or four in the carapace of the prosoma.Spider have anterior median eyes, anterior lateral eyes, posterior median eyes, or posterior lateral eyes. Scorpions and Spider  eyes are not compound but simple there is one lens for each eye . Spiders have poor vision  not able to see light and darkness. Scorpion and Spider  taxonomy are based on the forms and number of eyes. So the reasons to study these organisms are important in studies of  medical, ecology, morphology and taxonomy  and it is a little known about their biology and the  fauna for it.