Crustacean id

Images made through a microscope. All subject types.

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GaryB
Posts: 521
Joined: Fri Jul 29, 2016 12:18 pm

Crustacean id

Post by GaryB »

I found this little fellow trapped under some detritus I picked up at the sea. It slowly wriggled into view and was struggling to free itself. I don't know what it is but made a video here if anyone can id it.

Zeiss F-LD 20x/.25 LWD, with a mix of oblique and darkfield via homemade lucigen condenser

https://www.youtube.com/watch?v=qT-a4yzAsBs

Image

WalterD
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Location: Rotterdam, the Netherlands
Contact:

Post by WalterD »

Nice, thanks for sharing!
:)

eward1897
Posts: 16
Joined: Mon Feb 19, 2018 10:42 am
Location: Minnesota, US

propabable nauplius

Post by eward1897 »

I think your little crustacean is a nauplius larva. Crustaceans (and most arthropods) go through drastic changes as they go from egg to adult. Several different classes of crustaceans that look very different as adults have one-eyed free-swimming larva that look rather similar.

Your nauplius looks like a baby copepod (like Cyclops spp.) to me. Ostracods (so called seed shrimp) also have a nauplius stage, but like the adult the carapace (main 'shell') looks clam like in their larva. There is a brief "Key for the identification of crustacean nauplii" (= plural term for nauplius) at sciencedirect.com/science/article/pii/S1439609205000760 The text is directed towards professional biologists but Figure 2 shows good drawings of the nauplii of some different crustacean groups.

The study of nauplius larva probably had a role in the development of the theory of evolution. Charles Darwin studied the larval development of barnacles around the time it was being figured out what nauplii were. Some larval crustaceans were initially thought to be new species since they look so different from the adults. Watching the development of barnacles through different stages (barnacles have free-swimming nauplius larva and become strange, glued in place adults) could have prompted Darwin to think about how organisms may give rise to new species over time. Darwin pointed out how embryos are more alike than adults of different vertebrates in The Origin of the Species. It was the great German biologist-philosopher-artist Ernst Haeckel who put the idea so succinctly as "ontogeny recapitulates phylogeny."

ChrisR
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Post by ChrisR »

Welcome to the forum Eward!
Splendid first post (which will cost me some time on Wikipedia) :D
Chris R

GaryB
Posts: 521
Joined: Fri Jul 29, 2016 12:18 pm

Post by GaryB »

Wow, great reply. Thank you, and welcome to the forum!

Like Chris, I'll have to spend some time researching these guys. I found it in the Puget sound and it's the first of it's kind I've come across. Unfortunately, as soon as it freed itself in the video, it went straight back to the exact spot it escaped from and was trapped all over again :? I guess that's where the food was..

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