#ricinulei

(Sources - 1, 2, 3, 4)

Order: Ricinulei

Common Name: “hooded tickspiders”

Families: 1 - Ricinoididae

Anatomy: "hood" (cucullus) can be raised and lowered over the head; no eyes; very thick exoskeleton; complex pedipalps with small pinchers which can be used to not only manipulate food but also bear many sensory structures, used as short-range sensory organs; the second pair of legs is longest and are used to feel ahead of the animal, similarly to antennae; in males, the third pair of legs are uniquely modified to form copulatory organs

Diet: smaller arthropods

Habitat: leaf-litter or caves in west-central Africa and the Americas (from Brazil to southern Texas)

Evolved in: Late Carboniferous

(source)

Propaganda under the cut:

Hooded Tick Spider (Cryptocellus goodnighti), family Ricinoididae, Costa Rica

Hooded Tick Spiders are not spiders, but are in a separate order of arachnids, the Ricinulei.

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Did you know that Ricinulei is a relatively obscure order of small arachnids? Though no individual species has its own common name, the order as a whole is sometimes referred to as Hooded Tickspiders.

Yeah sure these little guys look cute, but what's really interesting to me about them is that they are considered a Lazarus taxon. That means that the order as a whole was present in the fossil record, disappeared for a substantial time, and came back. This usually happens in obscure, isolated, or extremely specific envrionments.

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InsertAnInvert2024

February Theme - Relationships: Courtship

Week 5: Hooded Tickspider (Ricinulei)

Between the long feeler legs, interlocking body segments, protective cucullus hood, and cool shades of red, these guys jumped right up to some of my fav arachnids. I'm in love~

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Hooded tickspiders (Ricinulei) are an order of small, predatory arachnids that feed on other arthropods. Despite the name, they are neither true spiders nor ticks. First described from fossils, these arachnids were once thought to be extinct, but more than 70 living species have since been described worldwide.

They are notable for their hood (or cucullus) which can be raised and lowered over the head; when lowered, it covers the mouth and chelicerae entirely. Hooded tickspiders have no eyes, but do have light-sensitive areas of cuticle on their exoskeleton.

After receiving a spermatophore from a male, the female will carry a single fertilized egg under her hood until it hatches.

wow! i’ve only ever seen one once, in Nicaragua, since they’re a super rare, strictly tropical group except for like a single species described from the rio grande valley in texas.

i’m afraid i wouldn’t be able to tell you anything about them that you couldn’t get from perusing the wikipedia article. the last time i thought about them was about a year ago when there was an uproar in the greater entomology community after someone published a paper purporting that horseshoe crabs are a sister group to hooded tick spiders based on DNA evidence. personally i think that’s total horse shit (horseshoe crab shit, even) and there’s a ton of ways that DNA-inferred phylogenetics can go wrong and molecular phylogeny dogmatists are deluded BUT ANYWAY that was a fun week of people yelling about arachnids.

good job on spotting a rare pet! send me pics!