The Other Species of Cellar Spider

2024 February 11

This spider was hanging around the bathroom, near the shower, on December 23, 2023. At the time I took the pictures, I thought it was another Pholcus phalangioides, which I had photographed several times before. These are common in houses, and are a well-known cosmopolitan species that lives in houses and basements all around the world. But then, I was made aware that there is not one species of cellar spiders in this genus in North America, but three. And one of those has a distinctive field mark, black stripes on the face between the eyes and the mouth. So I checked my specimen here more closely, and see that it does in fact have that mark! (which I have circled in red).

My previous pictures are lower resolution and most of them don’t show the face clearly, but this one from 2011 clearly shows that it did not have the field mark, meaning that these are two different species!

Old P. phalangioides photo from 2011

So anyway, this new one is therefore Pholcus manueli.

P. manueli is generally smaller, with mature P. phanalngioides getting almost twice as big. Both species occupy almost the same habitat, and both have been carried around the world by humans. P. manueli is a more recent arrival, though, and so are only now becoming common in the Midwest. Although, looking at my very first cellar spider photographs from 2008, I think that one may well have been P. manueli as well.

One Response leave one →
  1. February 19, 2024

    Oddly enough, the thing that jumps out at me from these photos are the joints in their legs, the ones closest to their bodies. They call to mind the joints of their deep-sea cousins, snow crabs.

    Now I’m hungry.

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