Chinese Hourglass Spider - 里氏盤腹蛛 - Cyclocosmia Ricketti

Chinese hourglass spider - 里氏盤腹蛛 - Cyclocosmia ricketti

The Chinese hourglass spider is a fascinating species of arachnid, a very rare one at that ! Between the years 2000 and 2016 ONLY six of these spiders have been spotted in China, that we know of.

@hispaatra, @zick-the-fairy more on the awesome seal :D

Chinese Hourglass Spider - 里氏盤腹蛛 - Cyclocosmia Ricketti

Description

Cyclocosmia ricketti has a very distinctive disk on its abdomen which resembles an ancient coin, a seal, or even a grinding disc. The male Cyclocosmia ricketti are about 20.5 millimetres in length while the females of the species tend to be slightly bigger at around 25.83 to 30.0 millimetres in length. The largest known specimens can exceed 30 millimetres. The disk located on its abdomen typically has a radius of around 16 millimetres.

Extract from 'Zhu, Zhang & Zhang, 2006 : Rare spiders of the genus Cyclocosmia (Arachnida: Araneae: Ctenizidae) from tropical and subtropical China.' Raffles Bulletin of Zoology, vol. 54, No. 1, p. 119-124

According to Zhao Li, Director and Senior Biological Engineer of the Insect Museum of West China in Chengdu, Sichuan, Cyclocosmia ricketti is a nocturnal animal.

Predation behaviour

Cyclocosmia ricketti, like many other trapdoor spiders, dig burrows which are closed off by hatches in the ground. They do this instead of making webs, as they are not good at spinning silk, to catch their prey. They line their burrows with silk threads and mud. They use their disk to plug the opening of the burrow. When a small insect would step on its disk, Cyclocosmia ricketti will then purportedly shrink its abdomen to allow its prey to fall further into its burrow to be devoured. The disk also makes it difficult for its prey to escape from its grasp.

Cyclocosmia ricketti doesn't always use this method to hunt, as when its confronted with a non-threatening insect, Cyclocosmia ricketti will get out of its burrow and then directly grab it to eat it. This spider can also use the coin-shaped disk on its abdomen to protect itself from enemies by blocking the entrance to its burrow with it, and using it as a shield, a phenomenon called 'phragmosis'.

Distribution

Cyclocosmia ricketti are found in the Chinese provinces of Fujian, Zhejiang, and Sichuan. They are primarily found living in caves. The farthest north they are known to have been found is Sichuan, this is notable as it was previously believed that Cyclocosmia ricketti were not able to survive in places where the temperature could drop below 13 degrees Celsius. Winters in the province of Sichuan are known to get even colder.

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Image sources:

https://za.pinterest.com/pin/604186106296940858/

https://spidershoppe.com/products/cyclocosmia-ricketti-chinese-hourglass-trapdoor-sub-adults

https://web.archive.org/web/20070811074158/http://rmbr.nus.edu.sg/rbz/biblio/54/54rbz119-124.pdf

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Text references:

Zhu, Zhang & Zhang, 2006 : Rare spiders of the genus Cyclocosmia (Arachnida: Araneae: Ctenizidae) from tropical and subtropical China. Raffles Bulletin of Zoology, vol. 54, No. 1, p. 119-124

https://web.archive.org/web/20070811074158/http://rmbr.nus.edu.sg/rbz/biblio/54/54rbz119-124.pdf

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

Wasps so tiny you will question everything.

Imagine being so teeny tiny that you are an endoparasite on *leafhoppers* Leafhoppers are already in the "so small they go unnoticed" category, and you're just a little pest on a minuscule thing.

Of course the group that's most likely to choose this life? The wasps Wasps are some of the smallest insects. There are "fairy flies" that are parasites of the eggs of certain insects.

They are so small that air is "thick" to them and their wings have feathered edges are are oar shaped.

Some fairly flies are so tiny that their neurons are cells without nuclei. They got rid of them to save space. They can still think though... presumably the tiniest little thoughts.

Photo by Alexey Polilov, 2012

Above is an adult wasp (A), to scale with single-celled organisms – Paramecium (B) and an Amoeba (C). The white bar at the bottom represents 200 micrometers (1/5 of a millimeter).

They lay their eggs inside of the eggs of 1-2mm long crop pests.

And... read the article to see what the males are like... they are even smaller somehow, but it's ... disturbing.

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taiisdelusional

11 months ago

If you think people used to willingly stare off into the distance before smartphones, my dad told me he had this psychology assignment when he was in college in the 80s which was basically

Go to a restaraunt by yourself and eat a meal without a newspaper or journal or anything else to keep you occupied and then write a report about it

Which tells me that this was a way for a professor to inflict psychological torture on their students and that people used to bring little things with them to keep them entertained. Shown by those old pictures of everyone in a trolley reading a newspaper with one hand.

Frankly I think that the human brain has been craving smart phone forever. Perhaps we use it too much at times but if this was 1985 we also wouldn’t be talking to people. We’d just be looking at newspaper or drawing stuff on notepad instead. And the old people would all be shaking their fists about how kids spend too much time looking at that damn TV because yes this discourse has been going on long before smart phone

98K notes View Post

taiisdelusional

2 years ago