Arachnids

Arachnids Latest News

A fossil harvestman identified using advanced imaging techniques shows that extinct arachnid lineages once lived in Europe.

About Arachnids

• Arachnids are chelicerates, one of the five groups of the phylum Arthropoda, which loosely means ‘jointed foot’. 
• These arthropods are primarily carnivorous, wingless, and have 8 legs.
• Like all arthropods, arachnids have segmented bodies, tough exoskeletons, and jointed appendages.
• Comprising around 100,000 species, there are more arachnids than all vertebrate animals (e.g., mammals, birds, fish, reptiles, and amphibians) combined. 
• They encompass various orders, including spiders, scorpions, ticks, and mites, making arachnids prevalent in terrestrial habitats across all continents, with some found in freshwater environments. 
• They are notable for their anatomical adaptations, such as specialized mouthparts for prey capture and unique respiratory structures, like book lungs and tracheal tubes.
• Arachnids lack jaws and, with only a few exceptions, inject digestive fluids into their prey before sucking its liquefied remains into their mouths.
• They exhibit various lifestyles, including free-living, predatory, and parasitic behaviors. 
• Noteworthy members include highly venomous species, such as the black widow spider and certain scorpions, which can pose risks to humans.
• At a glance, insects and arachnids are easy to mistake for one another. The two easy-to-spot differences between the two are:
  • Body segments: While arachnids have two body segments, insects have three body segments. 
  • Number of legs: Insects have six legs compared to arachnids’ eight legs.

Source: STD

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