LIFE SCIENCE

Detailed explanation-1: -Horseshoe crabs (Limulidae) are currently represented by four species including Limulus polyphemus (1), which is found along the eastern coast of North and Central America, and three Indo-Pacific species, Tachypleus gigas (4), Tachypleus tridentatus (3) and Carcinoscorpius rotundicauda (2).

Detailed explanation-2: -Horseshoe crabs (Xiphosurids) are perhaps one of the most well-known examples of “living fossil” because their bodies have changed very little over a vast length of time. They are not true crabs (which are crustaceans), but instead are chelicerate arthropods, making more closely related to spiders and scorpions.