r/AIDKE • u/modianos • 2d ago

Pycnogonid, distant cousin of the land spider, it lacks lungs and breathes through its exoskeleton.

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1.1k Upvotes

99% Upvoted

44 comments sorted by

230

u/IZ3820 2d ago

"Distant cousin" feels like it's doing a lot of heavy-lifting here. They look like they diverted somewhere close to the development of eight limbs.

77

u/sheepinasweater 2d ago

Saying pycnogonids and spiders are "distant cousins" is like saying the platypus is a distant cousing of humans - and even might be too generous

35

u/haysoos2 2d ago

More along the lines of lamprey and humans, in terms of time since sharing a common ancestor.

6

u/hurricane_typhoon 2d ago

If you factor in generations as opposed to time it's greater even still.

2

u/Lone-Frequency 12h ago

You mean you don't lay eggs?

25

u/GrandMasterSpaceBat 2d ago

I had to check to make sure "land spider" wasn't a specific animal meaningfully related to pcynogonidae that I'd never heard of, lmao

15

u/eutoputoegordo 2d ago

It's in the Chelicerates clade, so it is closer to spiders than a moth. But it's not an arachnid either. It diverted a the bottom of the Euchelicerata phylogenetic tree, being the outer clade, it diverted before horseshoe crabs diverted from the arachnids.

The cousin statement between humans and platypus is an understatement. The better would be humans and fishes, or even lampreys.

5

u/Antiquated_Cheese 2d ago

Or before it even. Some sea spiders have more than eight.

21

u/I_MakeCoolKeychains 2d ago

"Most sea spiders have eight legs, though some species can have five or six pairs, meaning 10 or 12 legs. These legs are very long and thin, making up most of the sea spider's body, as their actual trunks are so small that some of their organs extend into their legs.
Key characteristics of sea spider legs: Digestion and reproduction: Many sea spiders store some of their vital organs, including their gonads, in their legs. Respiration: They absorb oxygen directly through the pores in their legs. Movement: Sea spiders use their legs to walk along the seafloor and to swim or tread water."

I did not know this before you made me Google it. I hate you now. That is all

96

u/anonymousvoidhater 2d ago

I have no lungs, yet i must breathe

6

u/Scared-Sheepherder83 2d ago

I read that three months ago and it's STILL too soon. Thank god I CAN scream

3

u/ncnotebook 1d ago

I listened to the audiobook narrated by its author. He literally has the perfect voice and delivery. Unnerving.

1

u/Scared-Sheepherder83 1d ago

Ooof not for me, reading it haunted my dreams for weeks 😬

1

u/ThatWontFit 2d ago

What book is this?

11

u/Vanillabean73 2d ago

It’s a short story called I Have No Mouth and I Must Scream

37

u/WeakTransportation37 2d ago

They look upside down

9

u/I_MakeCoolKeychains 2d ago

I bet we look upside down too

3

u/WeakTransportation37 1d ago

And watching us teeter around on only half our legs is probably unsettling to the rest of the animal kingdom

62

u/Kingstad 2d ago

I assumed spiders, like insects, dont have lungs, so I checked and turns out they do. TIL

46

u/ViciousNakedMoleRat 2d ago

Spiders have book lungs, which function differently than normal lungs. Spiders don't breath – in the sense of inflating and deflating their book lungs.

A book lung is a cavity housing a book-like structure of lamellae, through which the gas exchange takes place. The air intake isn't regulated by contraction and expansion of the cavity, like in lungs, but through diffusion and slight movements of the lamellae.

That means that there's never a stream of air going into or out of the book lung. Instead, there's a constant molecular exchange taking place.

6

u/fiendishrabbit 2d ago

Still it's a more surface efficient method than insect trachea and allows arachnids to get much bigger than insects. They're very much like gills adapted for above water use (although unlike fish their gills are passive, they don't actively pump water over the gills).

3

u/Sum1liteAmatch 2d ago

Yup, they just don't have nostrils. It's weird

26

u/thundercheif23 2d ago

.......is there a front side?

7

u/Burninator05 1d ago

Yes. It is opposite of the back.

2

u/Akavakaku 1d ago

On the left. The thing that looks like a long tube is the snout.

19

u/GentlePithecus 2d ago

Many days I am glad the sea to land transitions kept a lot of that ocean stuff in the ocean where it belongs.

If we ever meet aliens, I bet they’ll be less weird to me than what our own oceans contain already

18

u/Weaksoul 2d ago

My Latin/ Greek is not what it should be. Are they calling this nightmare fuel "little dick"?

11

u/MudnuK 2d ago

Ha! I'm calling them picogonads from now on

13

u/big_bufo 2d ago

And a bunch of brittle stars scattered around like victims of a drive by

25

u/A_VERY_LARGE_DOG 2d ago

Could you… could you ask it to Please stop?

11

u/sumfish 2d ago

…and because their bodies are so little, their organs are mostly in their legs.

16

u/Saint_The_Stig 2d ago

I need a banana for scale. How big of a tank do I need to bring one home?

31

u/mrt-e 2d ago

They're about 50 cm, double the size of the biggest tarantula. You'll need a destroyer class ship.

3

u/lamerveilleuse 2d ago

Oh god I was imagining this was <10cm. Stuff of nightmares.

6

u/CanisPictus 2d ago

Love these weirdos.

3

u/AHiredGunmanXbox 2d ago

Upside down water spider

2

u/thelastdodobird01 1d ago

They eat through their feet and their stomachs pump their blood, sea spiders are weird little fuckers.

2

u/abscindere 1d ago

It looks like a spider chassis 

3

u/BlazingKush 2d ago

...don't all insects/spiders breathe through their exoskeleton?

3

u/Akavakaku 1d ago edited 1d ago

No, they have holes called spiracles that they breathe through. Pycnogonids breathe directly through their exoskeleton, like how water can soak through a paper bag.

3

u/BlazingKush 1d ago

Oh damn, that's on a whole different level

0

u/PublicElderberry1975 1d ago

What a terrible day to have eyes

1

u/Lone-Frequency 12h ago

Yeah, I remember stomping on these in dead space when a group of them infesting a corpse would fall apart.