Types of arachnids - My animals

Arachnids make up a large class of animals ( Arachnida ) belonging to edge of arthropods. Currently, more than 100 000 types of arachnids are known to spread widely throughout the planet, with the logical exception of Antarctica and the poles.

Next, we will see the main characteristics of these animals and we tell you which are the most common types of arachnids in the world .

General characteristics of arachnids

Like all arthropods, have eight legs and two pairs of appendages at mouth level. In some types of arachnids the two front legs suffered a Evolutionary modification by which they acquired sensory functions. In other species the appendices are so developed that they can become confused with legs.

The first pair of appendages are called 'chelicerae' and give name to the subfile of the quelicerados, to which the arachnids belong. Its main function is associated with food, but they are also powerful allies in its defense.

The appendices of the second pair are called 'pedipalps'. They are also essential for feeding arachnids, as they help capture prey. But its main functions are related to locomotion and reproduction.

The body of the arachnids is divided into two segments or tagmas: the cephalothora (or prosoma) and the abdomen ( or opisthosoma). Like all arachnids, they present an exoskeleton and its internal structure -where its vital organs lodge- that is composed of cartilaginous tissue.

The most characteristic feature that distinguishes arachnids from other arthropods is the absence of wings and antennae. In addition to its number of legs, in many cases.

The main types of arachnids on our planet

In the great class of arachnids There are 11 different orders, that comprise different species (some of them already extinct). These are the most common types of arachnids on our planet.

**1. Araneae (Spiders)**

Spiders make up the most diverse and abundant order in the class of arachnids ( Araneae ). Currently more than 40,000 spider species have been registered and described.

One of its most characteristic features is the presence of 'fangs' which, in reality, are its modified chelicerae. Through these 'fangs' poisonous spiders can introduce their toxins into the body of their victim.

Regarding their behavior and habits, highlights the amazing and recognized ability to build fabrics, woven by multiple silk threads. The so-called 'cobwebs' not only serve to trap their prey, but also act as shelters and can help them take advantage of the wind to move.

Despite its fame and its appearance, there are Very few spiders that pose a risk to humans . The vast majority of spiders have a shy and balanced nature, so they can hardly utter any attack on a person.

2.In fact, all species of scorpions contain certain toxins in their sting . But only 25 species of the cockatiel family are potentially dangerous to humans.
Another fascinating feature of scorpions is the natural ability to shine in the dark. The skin of these arachnids contains special chemical compounds that allow them to emit fluorescent rays under ultraviolet light. The purpose of this natural scorpion fluorescence is not yet clear.

3. Acarina (mites and ticks)

Although it is common to confuse them with insects, mites and ticks are also types of arachnids . Currently, about 50 000 species of mites and ticks are already recognized. Experts suggest that there could be up to 500,000 species in nature; according to this data, this would be the most extensive arachnid order in the future.

The most well-known species of mites are those that maintain parasitic habits: they are lodged in the skin of people, domestic and wild animals. In addition, the so-called 'dust mite' is one of the most common allergen agents.

Another curiosity about mites is that they are among the oldest animals in the world . The fossil analyzes have allowed to identify that this arachnid already lived in our planet about 400 million years ago, during the lower Devonian period.