Last of the crab-like spider thingys

[NorseThing]

Darth Vader may be Luke Skywalker's father (spoiler alert), but he could also be the twin of a horseshoe crab that lived 245 million years ago.




Paleontologists from the New Mexico Museum of Natural History and Science in Albuquerque and the University of Colorado at Denver have published a scientific article describing the extinct fossil horseshoe crab and its uncanny resemblance to the headgear Anakin Skywalker wears when he becomes Vader.

http://www.foxnews.com/science/2017/...tists-say.html

Horseshoe crabs are not actual crabs, as they are part of the Limulidae family and are more closely related to scorpions and spiders. There are only four species left on the planet, with population numbers dwindling.
The four types include the mangrove horseshoe crab (found in Southeast Asia), the Atlantic horseshoe crab (found in the Gulf of Mexico and along the Atlantic coastline), the Tachypleus gigas, (Southeast and East Asia) and the Tachypleus tridentatus, which is located in Southeast and East Asia.

Actually read the full story at the link. I am posting this because it is a local story (for me) and I cannot believe that it is so long ago that they can refer to dinosaurs and mammals as both developing. Last of a species for a lack of better words. Progress is sometimes a b*** for some.

[LinusLinothorax]

It's interesting to note that horseshoe crabs are closely related to the ancient sea scorpions (Eurypterids). These bad boys were most likely the first specialized "super predators" in Earths history, dominating the seas (and probably even the shores) from the Ordovicium to the lower / middle Devonian. The biggest one known so far, Jaekelopterus, got almost three meters long:

[NorseThing]

From a few years ago:

About 460 million years ago, a sea scorpion about the size of an adult human swam around in the prehistoric waters that covered modern-day Iowa, likely dining on bivalves and squishy eel-like creatures, a new study finds.

https://www.livescience.com/52052-an...n-fossils.html

More the article at the link as well. Thanks for the response LinusLinothorax. I thought this was interesting and not posted 'just' as click bait.

[Elfdude]

What do you think is interesting about it?

[NorseThing]

What do you think is interesting about it?

I am always amazed at the size of the creatures from our past times. How much tis has to do with changes in atmosphere and oxygen content in the oceans, I do not know. I am also always amazed at eotutionary 'dead ends' or what appears to be dead ends. due to competitive pressures from new and changed species as well as changes to the climate. Even the changes on ocean currents as contenents move and olcanoes rearrange the good order remind us of the fragile nature of things.

[Elfdude]

Ah, well the primary barrier to most arthropods is the oxygen content of the water, but they can get a lot bigger than horseshoe crabs even today, alaskan king crabs, japanese spider crabs and coconut crabs are all much larger.



I'd hesitate to call them an evolutionary dead-end, they're currently amongst the most successful lineages in the history of earth and have dominated the planet for far longer than either mammals or reptiles. On average a species tends to survive about 6 million years before being supplanted or driven to extinction, 400+ million years is an incredible thing.

The coolest thing about horseshoe crabs is by far their blood:



Their blood saves millions of lives each year. Every medicine, surgical implant or etc must be tested with LAL which is essentially what the crab uses for it's primitive immune system. This is probably the primary source of population degradation. Which is to say horseshoe crab blood is worth more than its weight in gold and the overuse of it to test drugs and prosthetic has resulted in a massive decline in the population. Combined with extraordinary population booms of seabirds eating their eggs we're losing a lot of this.

[NorseThing]

Wow!! I wonder if I had some of that blood when I was in the hospital for blood clots near my heart that were aggravated by my allergies. Of course, I as the patient just laid there -- the doctors would know more about that. Fascinating.

A remember a several decades ago helping a mate gather up rocky mountain fresh water jelly fish for dental calcification studies, but that is another story.