Bitten by flat Crab-like Spider
January 6, 2010
Hello Bugman, hopefully you can help me identify this night-time nibbler. You have requested I ‘provide as much narrative & information as possible’, so please forgive me if this is too wordy:
I am currently vacationing in La Paz Mexico, in the Southern California Baja. On December 28th ’09, I injured my left shoulder muscles lifting heavy luggage in an odd position. Then on the 3rd of January 2010 at around 11pm, I re-aggravated it while quickly getting out of a vehicle. Later on I went to sleep lying flat on my back as I was in a bit of pain, & felt I shouldn’t lie on my left side. The pain was however was not that bad, just felt like a pulled muscle (which I am familiar with as I do a lot of sports & have had various muscle strains before). I awoke around 1am on the 4th in extreme pain as I was rolling onto my right side. Initially I thought I’d again moved in an odd way, but the pain was so excruciating, I had to awaken my girlfriend to get me a bag of ice. As I sat on the edge of the bed waiting, I saw this little critter crawling slowly away, about 3 feet from the bed. As I’ve had a life-long love-hate fascination with spiders, I decided to cat ch it. When I approached with a large cup, I realized it had potential to move very fast, about 1 foot per second! I caught in nonetheless, and left it alive under the cup. We looked for bite marks but saw nothing anywhere on my torso. After a while, I felt the pain was such that I needed medical attention. I had since gone into shock, my entire left shoulder was swollen and painful, & I had what felt like blood poisoning pains in my left arm. We reluctantly awoke our friends whose house we are staying at here in La Paz. My friend looked at the spider, and said that in his 10 years of living here, had never seen anything like it. He then killed it. I decided to keep it around to find out what it was.

Tailless Whipscorpion

Tailless Whipscorpion

(Sidebar): A few years back I was vacationing in Costa Rica, and saw a spider that looked just like this one. It was on the ceiling of the cabin we were staying in high in a volcanic region called ‘Rincon de la Viejo’. When I blew at it, it scurried rapidly across the ceiling & disappeared into a crack about 1/8” thick. It would peek out every once in a while, & I would blow some air to watch it scurry away again.

So off we went to the hospital in La Paz around 2am on the 4th. Thankfully my friends speak Spanish & could describe the injury. We had a very competent Doctor check me out, who determined (& rightly so under the circumstances at the time), that I was merely dehydrated, and my muscles were tensing up to protect the muscle damage that had recurred. After a re-hydrating intravenous, 2 hours observation (because we told him about the coincidental sighting of the spider near the bed), he released me with a prescription for an oral pain killer/muscle relaxant, and a topical anti-inflammatory ointment. He also had me get a sling to support my arm. We arrived back at the house around 5am, & I went to sleep upstairs in an easy chair so my arm could be supported.

The next morning I felt marginally better, so I proceeded with the doctor’s orders & took the medication, arm in sling, rehyrated, etc…We went on with our day, albeit a subdued one. Later my shoulder started to feel a lot better, swelling reduced, and mobility increased. I didn’t even need the sling that much & wore it only off and on. Still no signs of any bites. We again slept upstairs, me in the chair, my girlfriend on the sofa beside me.

On the 5th, I felt like I was on the mend, so we went out and enjoyed the beach, & got home after sunset. Around 8pm my girlfriend noted I had a little blue-discoloration under my left pectoral. I thought it might have been a stain from the blue sling, but when I later removed my shirt around 11pm, I could clearly see 2 purple circles there side by side, about the size of nickels. That’s when we started taking pictures & we realized that the highly unlikely coincidence of the spider had bitten me in the same area I had repeatedly injured my shoulder muscle, was in fact an almost certain reality!

This morning we noticed that slight purplish coloration was developing along the underside of the pectoral muscle, although most swelling had subsided. So we took the spider & returned to the hospital to show the doctor. Upon examination, he immediately agreed that the spider had bitten me. I had forgotten to mention to him earlier that I usually have almost no reaction to bug bites such as wasps, hornets, mosquitoes, etc (I have worked extensively in Canadian forests, and received countless stings & bites, which resulted in a small red dot at best). Thankfully they had a spider/venom specialist there who also reviewed my injury & the bug in question. He told us he had in fact seen it before but couldn’t recall its name. He also said that in the last 10 years, it was only the 3rd time he’d seen the bug. He said it has highly toxic venom, and although not lethal, the last 2 victims had arrived in total paralysis, swollen throat, and were convulsing. They both had a f ull recovery. I am to return to the hospital this coming Monday for another checkup, and the Doctor says he will have the spider’s name for me then.

So now they have me on the following medication:
1) Tarifol Flex tablets – muscle relaxant & painkiller
2) Mesulid Nimesulida topical gel – anti-inflammatory
3) Meticorten tablets – steroid to counteract the bruising, which is apparently due to my body fighting the toxins, causing small capillary damage
4) Virlix Cetirizina tablets – antihistamine in case I start to have trouble breathing
5) Avelox tablets – antibiotics in case the bite itself becomes infected.

Sorry for the long explanation, but you asked! I am not asking for a doctor’s diagnosis, but would really like to know what I am dealing with here. Any info on this bug’s name, habitat, tendencies, toxicity, or whatever advice you have would be greatly appreciated!! If you would like to see picture of the bites & reaction, let me know I have lots!!
Aaron (once bitten, twice purple!)
La Paz, Mexico, Southern California Baja

Tailless Whipscorpion

Tailless Whipscorpion

Dear Aaron,
We sympathize with your injury as it is no fun being incapacitated at any time, much less while on holiday.  The creature in your photo is a Tailless Whipscorpion, a non-venomous arachnid.  In Mexico, they are called Cancles and there is a misconception that they are deadly poisonous.  We repeat, the Tailless Whipscorpion has NO VENOM.  It is possible that they might bite, but reputable accounts we have read call them  harmless, shy, nocturnal predators, despite the frightening appearance.  They are beneficial predators that will feed on troublesome insects like cockroaches that infest buildings.  Though they are not aggressive, we suppose it is possible that a person might be bitten by a Tailless Whipscorpion, but the bite would be little more than a pinch, and since there is no venom, the reactions you describe should not be attributed to the Tailless Whipscorpion.  If you were bitten by something venomous, that is a different story.  All we can say for certain is that the Tailless Whipscorpion is not a venomous creature.  Since you did not actually see anything bite you, we think you should let this poor, dead, Tailless Whipscorpion off the hook and search elsewhere for the cause of your pain and bruises.

2 Responses to Tailless Whipscorpion: Wrongly accused of a poisonous bite in Mexico

  1. lttlechkn says:

    I just wanted to point out that there are in fact different types of strained muscles…

    Intramuscular contusion

    This is when the muscle is torn within its protective sheath. Bleeding is limited to within the muscle, but pressure builds up because the fluid can’t escape.

    Intermuscular contusion

    This is when both the muscle and the sheath that surrounds it are torn. Blood can escape from the sheath so it’s easier for the bruising to come out and the injury to heal.

    Also, when left untreated with the commonly known method of PRICE (Protection, Rest, Ice, Compression, and Elevation) many pulled/strained muscles have the tendency to become worse in condition. If the poster plays sports often they should know this… Sorry I just think its highly unfair to blame an innocent creature when in all reality all the pain and bruising (that took longer to rise to the surface due to the type of pulled muscle, not a bite) is indeed their own doing. General rule of thumb, if there is swelling, when the swelling recedes you can pretty much guarantee there is gonna be a bruise. Also, with any bite that leaves a nickel size marking for each “fang” you can be pretty sure there would be some noticeable puncture wounds as well. The last time I was bit by a bug of any sort, which was a centipede, there were noticeable puncture wounds (though rather small). I also knew exactly when it bit me, because the bite itself was rather painful. Now I know that not every bite is initially painful, but for the most part they are. Okay I think I have said my piece… I do feel terrible that the innocent tailless whipscorpion met such an untimely death.

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