Spiders and lobsters belong to the phylum of animals called Arthropods, which means they are distantly related. The main feature they have in common is the external skeleton or the exoskeleton, which means they’re remotely related.
The group of arthropods is the largest phylum of animals in the world. It contains more than 10 million species. Both lobsters and spiders belong to this group, as well as snails, insects, and other types of crustaceans. They are both some of the oldest species in the world and have a shared evolution.
What is an Arthropod?
An arthropod is an animal that belongs to the phylum of arthropods. This phylum is the largest grouping of animals in the world.
A phylum is a grouping that is used to categorize animals according to their features and their evolution. It is the largest grouping of animals, and animals are then further split into subphyla, classes, orders, superfamilies, and families.
The animal kingdom is split into 31 different Phyla, which include Arthropods. Humans, for instance, belong to the phylum of Chordata.
Both spiders and lobsters are arthropods, so they share two main features because of this:
- An external skeleton or exoskeleton
- Joint appendages
The phylum of arthropods is by far the largest phylum of animals in the world, as it contains more than 80% of all animals in the world. This means that more than 10 million species belong to the group of arthropods.
Some of the most notable animals that also belong to this group are:
- Arachnids (spiders)
- And many others
How are Spiders and Lobsters Related?
Spiders are lobsters are distantly related because they belong to the group of Arthropods, meaning that they do have a shared evolution and a few features that they share as well.
Several spider species look similar to crabs or other arthropods.
Evolutionary speaking, it is highly likely that both lobsters and spiders stem from the same ancient animal – that is the velvet worm. It is one of the first arthropods in history, as it contains some features that arthropods still have today.
Their history goes 500-600 million years back. They’re believed to be a possible ancestor of all or most arthropods.
They had several features to share with the modern-day spiders, including a chitinous shell (albeit a much softer one), and joint appendages. It also undergoes a molting process just like most spiders do, making it one of the most probable ancestors of both spiders and lobsters.
The evolution of spiders and lobsters changed about 100-150 million years ago when they started to develop their own features. Lobsters became acclimated to the sea and developed several features that allowed them to survive underwater.
The first known spider species is the Trigonotarbids, which evolved from underwater life. They were the first spider species that live out of the water. Even though it couldn’t spin silk, it had some features that resemble today’s spiders. These were not true spiders, but one of the first species that had spider-like features like chelicerae and terrestrial lifestyle.
What Do Spiders and Lobsters Have in Common?
Spiders and lobsters have two main features in common:
- Joint appendages
It is these two features that mean they both belong to the category of arthropods.
Their exoskeletons are fairly different, though. Spiders have a slightly thinner exoskeleton and for younger spiders especially, it is not as tough as the exoskeleton of young lobsters.
Because they have an exoskeleton, they also both go through periods of molting. Molting is necessary for both species since it allows them to grow their body and adapt the exoskeleton to the growth. Younger spiders and lobsters will molt at much faster rates than adults.
Related: Why do Spiders Molt?
In addition, both species will also lay eggs. This feature is thought to have stemmed from their shared ancestry. When they mate, the female will lay eggs. After a short period of gestation, the eggs will start to develop, and soon after, babies will start to crawl out of these eggs.
Another important similarity is the segmented body. They both have joint appendages and a two-part body. This means that their body structures are quite similar, even though they might appear to be slightly different on the outside.
Even though spiders and lobsters are different species, they have some things in common. These similarities point to their path of evolution, as it shows that they are still distant relatives, although their evolutions have taken different paths along the way.
These are some of the main features that spiders and lobsters have in common. However, there are also many differences between these two creatures.
What are the Differences Between Lobsters and Spiders?
The main differences between lobsters and spiders include:
- Lobsters have gills and aquatic lungs – this means that spiders cannot survive underwater for very long, while lobsters are well suited to living underwater, and will struggle to survive on land.
- Spiders can create webs from their silk – the first spiders could not create webs with their silk as they did not yet have the capacity to do so, but with evolution, they developed silk glands. This is a feature that is fairly unique to spiders and you won’t find it in lobsters, that’s for sure.
- Lobsters have five pairs of legs – this is yet another crucial difference between these two species. Spiders mostly have eight legs, while lobsters have up to ten.
- Spiders have venom – lobsters don’t have venom, while spiders have it. It is one of their most important mechanisms for survival, as it enables them both to hunt other animals and defend themselves.
To conclude, lobsters and spiders are distantly related. They both belong to the group of animals called arthropods, which is a large group of animals that contains spiders, lobsters, insects, and other animals with an exoskeleton.
There are also some crucial differences between the two. Most notably, lobsters have aquatic lungs which allow them to survive underwater, while spiders can only live on land.