American Arachnological Society (AAS)

@arachnology.bsky.social

The official account of the American Arachnological Society (AAS). AAS furthers the study and appreciation of arachnids, and publishes the Journal of Arachnology. 🕸️🕷️🦂 & other wonderful #arachnids! https://linktr.ee/american_arachnology

Are you a student interested in Arachnology? Join our annual virtual student social is happening soon! 🕸️WHEN🕸️ Sunday, June 8, 6:30pm CST 🕸️WHERE🕸️ AAS student Discord 🕸️How to Register🕸️ If you’re not in the student Discord, send us a DM and we will share the link with you.

Arachnology students gathered at night for collecting arachnids

Spider Biology Field Course!! from July 1 - 9, 2025 experience the outstanding biodiversity of spiders and non-spider arachnids found in montane southeastern AZ; taught by Greta Binford, Paula Cushing, & Marshal Hedin $946 for tuition, room & board. See www.amnh.org/research/sou... for details.

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Whip spider (Paraphrynus laevifrons) covered with chloropid fly puparia. The parasitoid fly attacks the eggs carried by the female. When done, the maggots climb on the "childless" mom's back and pupate. She protects them during this period thanks to her motherly instincts.

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Titiotus heberti from the mountains of Kern County CA. the large hook-like structure on the pedipalps (in the front) is called the "retrolateral tibial apophysis" (=RTA). turns out that this feature defines a large natural group of spiders Titiotus is species rich, all endemic to California

iridescent pinkish adult male spider with complex pedipalps (appendages in front of the eyes)

Here are your Friday Scorpion Fingers. This scorp is in the genus Serradigitus, or sawfinger scorpions. They are called this not because they will saw off your finger, but for the uniform, saw-like teeth on their chelae (singular chela), which is the science-y word for their pincers. 🐙 #invertebrate

A macro photo of an orange-ish colorlored scorpion's claw, with the scorpion's head visible, out of focus, in the background.

🧪Xiphosura AKA Horseshoe crabs have been moved across the Chelicerate phylogeny several times ▶️Xiphosura was once its own class separate from arachnids due to their distinct body shape ▶️Recent molecular studies place them WITHIN Arachnida, labeling them arachnids Should we allow Xiphosura memes? 😎

A meme of Patrick Star from Spongebob. He is labeled as a taxonomist saying "Let's take Xiphosura, and put it somewhere else."