Fun fact: horseshoe crabs are not only not crabs (infraorder Brachyura), not only are they not decapods (order Decapoda), and not only are they not class Malacostraca, they’re not even crustaceans (subphylum Crustacea).
Instead, they’re in the subphylum Chelicerata, making them more closely related to a tarantula, a daddy longlegs, and a tick than they are to any crab.
My favorite horseshoe fact is that they have nine eyes, of all different types. And that’s not even counting the tail which is itself covered with photoreceptive cells - so it’s essentially a tenth eye.
It is! he’s a biologist that has gone through phylogenies of many living creatures with the goal of hitting every clade I believe. I’ve found him recently, so I can’t say I really know. But, I’ve been watching a lot of it. It’s fascinating.
I was under the impression that chelicerates were categorized as crustaceans, along with hexapoda. I’m not an expert in this, I just watch the phylogeny videos of Clint’s Reptiles and AronRa.
Close. Arthropoda is the phylum under Animalia. From there you have the four subphyla Crustacea (crustaceans), Hexapoda (insects), Myriapoda (centipedes and millipedes), and Chelicerata (chelicerates). So they are closely related relatively speaking, but they’re separate subphyla.
If anything, funnily enough, the clade Pancrustacea is comprised of just crustaceans and hexapods to the exclusion of myriapods and chelicerates. Even more messy – I learned just now that – is that Arthropoda can be divided into two clades Chelicerata and Mandibulata (where Mandibulata contains myriapods and Pancrustacea), so in reality, not only are horseshoe crabs more closely related to a black widow spider than to crabs, but crabs are substantially more closely related to a mosquito than to horseshoe crabs.
Fun fact: horseshoe crabs are not only not crabs (infraorder Brachyura), not only are they not decapods (order Decapoda), and not only are they not class Malacostraca, they’re not even crustaceans (subphylum Crustacea).
Instead, they’re in the subphylum Chelicerata, making them more closely related to a tarantula, a daddy longlegs, and a tick than they are to any crab.
They are part horse though, right?
Actually, part shoe.
And like many a shoe, has 10 eye-let
My favorite horseshoe fact is that they have nine eyes, of all different types. And that’s not even counting the tail which is itself covered with photoreceptive cells - so it’s essentially a tenth eye.
A fellow Clint’s reptiles enjoyer?
Is that a YouTube channel?
It is! he’s a biologist that has gone through phylogenies of many living creatures with the goal of hitting every clade I believe. I’ve found him recently, so I can’t say I really know. But, I’ve been watching a lot of it. It’s fascinating.
Omg that’s so cool. New thing to binge at work on slow days. 😎
Thanks!
I was under the impression that chelicerates were categorized as crustaceans, along with hexapoda. I’m not an expert in this, I just watch the phylogeny videos of Clint’s Reptiles and AronRa.
Close. Arthropoda is the phylum under Animalia. From there you have the four subphyla Crustacea (crustaceans), Hexapoda (insects), Myriapoda (centipedes and millipedes), and Chelicerata (chelicerates). So they are closely related relatively speaking, but they’re separate subphyla.
If anything, funnily enough, the clade Pancrustacea is comprised of just crustaceans and hexapods to the exclusion of myriapods and chelicerates. Even more messy – I learned just now that – is that Arthropoda can be divided into two clades Chelicerata and Mandibulata (where Mandibulata contains myriapods and Pancrustacea), so in reality, not only are horseshoe crabs more closely related to a black widow spider than to crabs, but crabs are substantially more closely related to a mosquito than to horseshoe crabs.
Thanks for the info, I love learning this kinda stuff.
Well that checks out, considering they are more terrifyingly stranger then any other crab.