Arthropods: List of Popular Arthropods with Useful Facts

The animal kingdom, scientifically referred to as Kingdom Animalia, encompasses a diverse array of animal species. This kingdom is further divided into various phyla for classification purposes.

Within Kingdom Animalia, one of the prominent phyla is Arthropoda, commonly recognized as arthropods. Arthropoda stands as the largest phylum within the animal kingdom. This article delves into a comprehensive exploration of the fascinating world of arthropods.

What Are Arthropods?

Arthropods, as invertebrate organisms, are distinguished by their numerous joints, as well as possessing a chitinous exoskeleton and a segmented body. The exoskeleton, an external covering that shields and supports the body, typically resembles a shell. Comprising chitin and proteins, an arthropod’s exoskeleton consists of layers, hence the term “chitinous.” Despite the animal’s growth, the exoskeleton does not expand and must be periodically shed and replaced, a process known as molting.

With bilaterally symmetric segmented bodies, arthropods possess paired and articulated appendages, hence the derivation of the term “jointed feet.” The presence of these jointed appendages allows for enhanced flexibility, often serving functions like walking and sensory perception.

Encompassing over 80% of animal species, arthropods represent the largest phylum within the animal kingdom. They inhabit diverse habitats, leading to variations in their structure and developmental history. The subsequent section of this article delineates and examines the distinctive features of each arthropod type.

Different Types of Arthropods

The diverse array of arthropod species necessitates their further classification into distinct types or subphyla based on evolutionary relationships. The following outlines the five different subphyla of arthropods:

1. Chelicerates: Arthropods belonging to the subphylum Chelicerata, or chelicerates, are identified by their specialized pair of appendages called chelicerae, used for seizing and subduing prey. This subphylum comprises three classes: Arachnids, Xiphosura, and Pycnogonida.
   • Arachnids: spiders, scorpions, pseudoscorpions, schizomids, harvestmen, ticks, mites
   • Xiphosura: horseshoe crabs
   • Pycnogonida: sea spiders
2. Crustaceans: The subphylum Crustacea, or crustaceans, encompasses over 50,000 species, the majority of which are aquatic. They possess a head with two pairs of antennae, a thorax with four pairs of legs, and an abdomen.
   • Barnacle
   • Crab
   • Crayfish
   • Krill
   • Lobster
   • Prawn
   • Scampi
   • Shrimp
   • Woodlouse
   • Yabby
3. Hexapods: Hexapods, characterized by their six dedicated walking legs, include over one million described species, with the majority falling under the class Insecta (insects). While most are terrestrial, some also reside in freshwater and coastal marine waters.
   • Insects: ants, bees, butterflies, cicadas, dragonflies, mantises, mosquitoes, etc.
   • Springtails
4. Myriapods: Myriapods, named for their “many feet,” encompass creatures with varying leg counts, ranging from ten to hundreds. These arthropods feature forcipules on their heads acting as poison claws. Myriapods are predominantly land-dwelling, with most being herbivores, except for predatory centipedes.
   • Centipedes
   • Millipedes
   • Pseudocentipedes
   • Pauropods
5. Trilobites: Trilobites, now extinct marine creatures, were part of the arthropod phylum. Recognizable by their distinctive three-lobed, three-segmented structure, they have left behind informative fossils. Various orders within this group include Agnostida, Redlichiida, Corynexochida, Odontopleurida, Lichida, Phacopida, Proetida, Trinucleida, Asaphida, Harpetida, and Ptychopariida.

Common Arthropods | Facts

Here are the truths about some misconceptions regarding the members of arthropods:

Spider

Spiders, characterized by eight walking legs and two chelicerae, belong to the class of arachnids, not insects. Insects, on the other hand, fall under the category of hexapods and are recognized by their possession of six walking legs.

Scorpion

Scorpions, often mistaken for crustaceans due to their appearance, belong to the class of arachnids, not crustaceans. Their resemblance to crabs or lobsters can be misleading, but in actuality, scorpions share a closer relation to spiders within the arachnid class. Similarly to spiders, scorpions possess eight legs and chelicerae that they employ for capturing prey.

Hexapods

Hexapods are the most diverse among all arthropods in terms of species number. Almost all the species of hexapods are insects.

Trilobites

Trilobites, the earliest-known arthropods, have long been extinct. However, the discovery of their fossils serves as evidence of their past existence.

Compound eyes

The majority of arthropods possess compound eyes located either on their heads or at the ends of their eyestalks. In contrast, spiders exhibit a distinctive arrangement of eyes.