The size of an Armadeira


Spring is coming, and with it, many buggies will begin to visit my backyard. I hope to see lots of tiny Chicago creatures, and put my macros to work :)

While I wait, I decided to make a post about the Phoneutria sp. spiders again because, well, they’re awesome.

Armadeira is the common name of the Phoneutria genus in Portuguese. In English they are known commonly as brazilian wandering spiders.
There are 8 species in this genus. Out of these, 5 are exclusive to the Atlantic Forest region:

Map from Biodiversity Hotspots

The Atlantic Forest, being near the coast and in a region of Brazil with very fast metropolitan growth, has been massively devastated. Today, only 7% of the forest remains :(

It’s very common to hear reports of wild creatures “invading” the cities. Sometimes the firemen have to capture an alligator or a large feline from somebody’s backyard, and even in the heart of a 20 million inhabitants city, you can still see capybaras feeding by the shores of the polluted rivers.
Naturally, spiders and other arthropods are also common visitors even in urban areas. That, along with Phoneutria sp. feisty temper and living habits contributes to the large number of spider accidents every year.

Fortunately for me, the little piece of the world where I grew up is one of the last places where you can still find parts of the forest untouched by men. Our neighborhood is surrounded by forest preserves, and that explains the diversity of insects, arachnids, and all kinds of animals I would find in my backyard. Growing up among such a diversity of animals, both dangerous and harmless, teaches you to respect nature and to know your place.

Uh.. oh yes, armadeiras.
So, since there are 8 different species, the sizes vary quite a bit. The two more commonly seen in the South East (where I lived) are the P.nigriventer and the P. keyserlingi.

The P. nigriventer is not that big (for a Brazilian’s standards anyway). They grow up to 3 inches, which is about the same as many wolf spider species we get in Brazil. That causes a lot of confusion to be made. If you’re in Brazil, and you’re not very familiar with these spiders, it’s best to give it a very careful poke with a broom and see how it reacts. If it runs away, it’s a wolf spider, if it tries to kill you, it’s an armadeira.
Here I put a 5 cents coin for size. It’s about the same size as a nickle.

Phoneutria nigriventer2

Now, the P. keyserlingi is huge. They can grow up to 5 inches, which is just a little smaller than my hand. These tiles were 1 foot long.

Phoneutria keyserlingi3

I have never seen any of the other species in person, but they all seem to be within that 3-5 inches range.

Talking about the deforestation of the Atlantic made me a little sad. Here’s a song that will make sense to my 1 or 2 Brazilian readers.

Tags: , , , , , , ,

15 Responses to “The size of an Armadeira”

  1. Michelle says:

    I had never heard of this spider so I Googled it and found that they are highly venomous. Phoneutria is greek for “Murderess”. I figured it must not be very docile when you said “If it runs away, it’s a wolf spider, if it tries to kill you, it’s an armadeira.” YIPE! Do you find them often? And what do you do with them when you do find them?

  2. BugLady says:

    Hi Michelle. No, we don’t find them very often, and that’s probably a good thing :)
    When we find it, we put it in a jar and take it into the woods. These spiders jump really tall, they can do a 3 feet jump and get you right in the face, so when we’re trying to get it into the jar, we always approach it from behind.
    If you still haven’t checked out, I made some other posts about these spiders. They can be found on the spider section in the bar on top of this page.

  3. new moon says:

    hey impressive little blog site you got right here :) I am using the exact same template on my own though for whatever odd cause it looks to load faster on this web site eventhough your own carries even more material. Are you getting any kind of plug ins or widgets that will quicken it up? If you could possibly show the names so that I can use them on my blog so twilight eclipse users could watch twilight eclipse online trailers and films more quickly I’d personally be ever so pleased – many thanks ahead of time :)

    • BugLady says:

      Hi, sorry for taking so long to reply. Your comment fell in my spam folder.

      This template was initially very slow, specially with all the pictures, it would take over a minute and sometimes it would time out.

      After making some guesses and trying some things, I thought I had to do something about storing cache better, so I installed the WP-SuperCache Plus plugin and did a little configuring and now it loads fast for everyone, so it works :)

      Give that plugin a try and let me know if you need any help.

  4. Techuser says:

    Found this site by searching for spider eyes
    You lived in Brazil or found these in some travel? You positive about keyserlingi and nigriventer identifications? I never read anything about the differences but for me both could be in the 15cm legspan

    Also the behavior is not always so standard like that haha
    I might be lucky but to this day I never saw an agressive phoneutria, everytime they just get away from me if I poke them, to the point of being able to handle one once
    Wolf spiders in the other hand can also be pretty angry and also display that erect defensive posture sometimes
    The most common species where I live, L. erythrognatha (former L. raptora), was thought to be venomous for quite sometime because of bite misidentifications with phoneutrias

  5. BugLady says:

    I am from Sao Paulo, but I have been living in Chicago for the past 2 years. These are pictures that I look over the years.
    I am hesitant to say that I am absolutely certain about any identification I make, since I’m really just a hobbyist, but looking at pictures of both spiders, there are characteristics of each one besides the legspan, like these big hairs on the legs:
    … and on this one, the little white dots on top, and the dark rings in the back of the legs and the way it stands up and all that :)

    But you know… finding specific descriptions of each species is quite difficult, so I’d love to read more if you have any references to make!

    And my experience with phoneutria was the opposite of yours, I’ve only met extremely aggressive ones. I didn’t even have to poke these ones, just approaching them was enough to get them wanting to kill me dead haha. Anyway, the aggressive behavior is pretty well documented and it’s something that they are known for. I think that the calm ones you met might be the exception… maybe they’re from Bahia lol.

    I have a picture of a L. erythrognatha on here too… check it out

    BTW the pictures on your flickr are awesome.

  6. Techuser says:

    Thanks… did you see my ctenidae set? :D
    accepting comments in portuguese?
    I’m also just a hobbist mostly, I do study biology but still regarding invertebrates its all from personal experiences/reading

    I also dont know for sure about the IDs, didnt asked to be pokey :)
    but the characteristics you said I think its more from sexual dimorphism, like I never saw a male with the white dots like that female has
    A difference I use to see in females happens to be on the abdomen drawings, the stripes at their back, but that could also be just variatons on specimens level

    One other thing that leds me to think 99,9% of the ones we see are nigriventer, is a really diferent one I found once, the chelicerae color was faded out, no abdomen markings and the overall body had different proportions.. that one was clearly not a nigriventer, its not on flickr but I will put on imageshack for you to take a look

  7. Techuser says:

    Look what I found in a 2007 paper abstract
    “Phoneutria keyserlingi (F.O. Pickard-Cambridge, 1897) and P. pertyi (F.O. Pickard-Cambridge, 1897), currently listed as junior synonyms of P. nigriventer (Keyserling, 1891), are revalidated and a modern redescription of P. pertyi is presented”
    Now we need to see what that revalidation led to, and which one is the pertyi, for the looks of it seems that keyserling and phoneutria are the same and pertyi turned to be a true different species
    the arcticle is for subscriptors only but I’ll try to get it

    This is the strange one I thought to be keyserlingi
    …. maybe now its a pertyi? lol

  8. Techuser says:

    lol I’m flooding your comment box :D
    Today I got the article directly from the authors, I can send it you if you want
    it says that til 2001 nigriventer and keyserling were synonyms, now on 2007 they were separated in different species again with this publication
    “Most recently, Simó and Brescovit (2001) synonymised both P. keyserlingi and P. pertyi with P.nigriventer, stating that these two species are just morphological variations of P. nigriventer.”

    It contains keys and photos for the species
    pertyi is a lot different, has a whiteish tone and I never saw one
    the photo I linked on the comment above is indeed a keyserlingi, and the overall way to identify them without having to look at the genitals is to look at the ventral side, nigriventer (as the latin name says and I never paid attention to it) has a darker belly, black in the females, keyserlingi have the underside “brownish to orange with a distinct orange shield”.

  9. BugLady says:

    Hey that’s awesome info! I wonder if I have any pictures from these two spiders that show the underside of the abdomen in detail.

    Maybe it’s time to write another post clearing all of this up… you can be my contributor, hehe.
    I’d love to read that article. Maybe you can send it to me at

  10. G’day, It’s great to find a good blog like this one. Do you mind if I use some of your info, and I’ll leave a link back to your website?

  11. BugLady says:

    I don’t mind it at all, Gerardo! Just keep in mind that everything I write on here is open to discussion and to corrections. I’m just an enthusiast :)

  12. Hector says:

    Hello, and greetings from Mexico. I congratulate you on your blog, I enjoy reading it a lot. I found your page because the BBC published an article about the medicinal properties of the venom of the armadeira spider. As an Homeopath we use spider poison as remedies, but not this one (yet). I believe it can be a wonderful addition to the repertoire against illnesses. Thanks for your time! Muito obrigado! Hasta la vista!

  13. [...] a really fun bug blog, check out The Bug Lady.  My favorite post is the one about the Brazilian Armadeira spider… it tries to kill you.  [...]

  14. Ébano says:

    Sim cara eu sou brasileiro e li seu artigo e achei simplesmente “wonderful” porque explica muito sobre a vida de seres extraordinários que eu tanto adoro e protejo, pena que primeiramente você precisa aprender a admirar tal beleza. Thank you very much man. (Unfortunately it seems to be that I am the first brazilian to read this article).

Leave a Reply