The Official(?) Arthropod Prehistory Thread!

[CladeArthropoda]

So, I don't think there is any better place to put this, if so admins can move it. Anyway, onto the point...

Welcome to the Official(?) Arthropod Prehistory thread! This is the thread where you can post about anything relating to the prehistory of arthropods. They can be recent discoveries or the can be things discovered years ago but not many people know about it. I made this thread because most people, even within this community, don't know a lot about the prehistory of our favorite animals. So, I figured I would do something about it. And here we are. Posts can be about the anatomy, phylogeny, evolution, behavior, ecology, etc about extinct arthropods. You can post about pretty much anything here, as long as it's about arthropods and prehistory. Without further a due, let's begin...

I will start things off with a cool group, Kalligramatids. Kalligrammatids are a large, diverse group of Jurassic and Cretaceous lacewings which greatly resembled butterflies, and also preformed a similar ecological role.

Their resemblance to lepidopterans goes beyond the initial first impression, as they had a proboscis, eye spots on wings, and even wing scales. They where also the largest ever Neuropterans, with the largest having a wingspan of up to 6 inches. The plants they pollinated where not angiosperms, but rather other seed plants such as some conifers.

https://en.wikipedia.org/wiki/Kalligrammatidae

 

[schmiggle]

There's megarachne, a medium sized eurypterid that was originally believed to be a giant (20" legspan) spider.

Anomalocaris, an oddball Cambrian arthropod with a row of oar-like extensions down each side that would undulate through the water looking for morsels. It was originally believed to be a shrimp, until the mouthparts were found attached to the body in a complete fossil and a very different picture emerged.

Rhizocephala are crab castrating parasites that have larvae like those of barnacles, but I've seen at least one suggestion that they're a result of horizontal gene transfer between a barnacle and something from a wholly different phylum.

 

[The wolf]

There's megarachne, a medium sized eurypterid that was originally believed to be a giant (20" legspan) spider.

Anomalocaris, an oddball Cambrian arthropod with a row of oar-like extensions down each side that would undulate through the water looking for morsels. It was originally believed to be a shrimp, until the mouthparts were found attached to the body in a complete fossil and a very different picture emerged.

Rhizocephala are crab castrating parasites that have larvae like those of barnacles, but I've seen at least one suggestion that they're a result of horizontal gene transfer between a barnacle and something from a wholly different phylum.

Anomolacaris weren't Arthropods,they're too primitive

Obv you've got meganeura,arthropleura,jakelopterus etc

Then you've got the largest spider originally believed to be in the nephilia genus but it's recently been discovered to be more closely related to deinops,how similar were not quite sure but it's unlikely it has the same fine honed hunting technique athough perhaps it did,isn't that a thought

Or what about pneumodesmus the first myrapod and th first air breathing animal ever discovered

 

[CladeArthropoda]

Anomolacaris weren't Arthropods,they're too primitive

Weeell, it's a little more complicated than that. I've seen some phylogenis include anomalocarids as arthropods.

However, this thread is necessarily only for extinct arthropods per say. You can also post on how other organisms may have effected the evolution of arthropods. For example, how the phylogeny of mammals correlate with the phylogeny of lice. Or how insects and plants have coevolved in Earth's past.

 

[The wolf]

Weeell, it's a little more complicated than that. I've seen some phylogenis include anomalocarids as arthropods.

However, this thread is necessarily only for extinct arthropods per say. You can also post on how other organisms may have effected the evolution of arthropods. For example, how the phylogeny of mammals correlate with the phylogeny of lice. Or how insects and plants have coevolved in Earth's past.

Oh ok I didn't know that I just assumed they were older than that and not technically classified as Arthropods bug I guess I'm probably wrong then

Yeah ik it's just he said anomalacaris was an Arthropod and at the time obv I didn't know nay better

Sry

 

[CladeArthropoda]

Oh ok I didn't know that I just assumed they were older than that and not technically classified as Arthropods bug I guess I'm probably wrong then

Yeah ik it's just he said anomalacaris was an Arthropod and at the time obv I didn't know nay better

Sry

Don't fret, you're not entirely wrong. Anomalocarids do lack many features seen in crown group arthropods such fully sclerotized exoskeletons.

 

[The wolf]

Don't fret, you're not entirely wrong. Anomalocarids do lack many features seen in crown group arthropods such fully sclerotized exoskeletons.

Aight I get u thx

 

[schmiggle]

Oh ok I didn't know that I just assumed they were older than that and not technically classified as Arthropods bug I guess I'm probably wrong then

Yeah ik it's just he said anomalacaris was an Arthropod and at the time obv I didn't know nay better

Sry

Anomalocaridids coexisted with trilobites, which are definitely arthropods, but they're weird and no one really knows what to do with them. Like many other early panarthropods, I've seen them classified in a clade with Obapinia as velvet worms. I just forgot.

Beetles diversified in tandem with plants, first gymnosperms and then angiosperms (in a much bigger way). Magnolia, an early (and still extant) flowering plant, seems to be adapted to beetle pollination.

The most primitive lepidoptera have mandibles, and some are adapted to eat moss as adults, an unusual food source generally and particularly out of place in an order that almost exclusively consumes nectar as imagos.

Edit: I've found a paper that says that Micropterigidae mostly eat spores and conifer pollen, so I wonder if some eat moss spores and not the leaf-things (moss doesn't produce true leaves).

 

[schmiggle]

Don't fret, you're not entirely wrong. Anomalocarids do lack many features seen in crown group arthropods such fully sclerotized exoskeletons.

How can you tell the degree of sclerotization from a fossil? That sounds very cool.

 

[CladeArthropoda]

You know what's funny? Jaekelopterus is considered the largest arthropod even though Hibbertopterus is only slightly shorter in length and much bulkier. The latter is quite possibly a good deal heavier than the former.