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3 Dec, 12 tweets, 6 min read

Another #ScienteaficABC. AMAUROBIIDAE! This family comprises 49 genera & ~275 species & can be found mostly around the world save for large swathes of the African, Asian & Australian continents, the Arctic & Antarctica. (images Wikimedia Commons & my own).

Amaurobiid spiders are generally quite rounded & velvety looking, not too vibrant or brightly coloured in most cases (though as you can see here, A. similis does try!), vary in size from 5-30+mm body length, & tend to inhabit cracks, crevices & other sheltered spots. (Pic: mine)

As with other spider families, eye arrangement is helpful (though by no means foolproof) in identifying Amaurobiidae. Here, enjoy another of my terrible diagrams! I shall accompany it with a photo to show you how they look on an actual A. fenestralis. (Image: Wikimedia Commons)

Amaurobiidae are entelegyne spiders, which means they possess complex genitalia. To explain further needs its own thread, but for now it is relevant bc entelegynae is further split into 2 clades- dionychia & trionychia. What does this mean & why is it important? (Pic: mine)

Dionychia = 2 clawed spiders. Trionychia = 3 clawed spiders. Amaurobiidae fall into the latter category which segues nicely into the next tweet. They are cribellate spiders, and all cribellate spiders are 3 clawed. Not all 3 clawed spiders are cribellate though! (Pic: Wiki)

Amaurobiidae contains both cribellate & ecribellate spiders. And that means? Well, cribellate spiders have special silk spinning apparatus that enables them to make wooly, tangled masses of superfine silk strands that rely on electrostatic interactions for adhesion. (Pic: mine)

Cribellate silk looks bluish white when it's fresh, fluffy/stretchy, & is v effective at ensnaring prey due to it being almost impossible to disentangle from, expecially if you're an insect with lots of spines & hairs etc. The cribellate species create 'regular' silk. (Pic: mine)

Finally, if you're in the UK & you go out at nighttime now, you're likely to see mature males out & about. I have lots on my doorstep every night! Also, these are not a medically significant family. Much like Agelenidae, a bite would be unusual & harmless anyway. Lovely spiders!

I made that video a few weeks ago before I knew I'd be doing this so forgive the fact I'm repeating myself! Images used in this thread are my own and also these from Wikimedia Commons.
commons.wikimedia.org/wiki/File:Amau…
commons.wikimedia.org/wiki/File:Blac…
commons.wikimedia.org/wiki/File:Amau…

@threadreaderapp

@threadreaderapp unroll

Goddamnit, I left out the bit about matriphagy... I'll have to talk about that in one of the other relevant family threads, but just FYI, some Amaurobiid species exhibit this behaviour. Matri = mother, phagy= the act of eating. The young eat their own mother.

@Tone_Killick

You can read a bit about it here on the magnificent @Tone_Killick's blog: tonekillick.blogspot.com/2016/07/matrip…

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More from @tea_francis

🕷scienTEAfic🕷

@tea_francis

4 Dec

Today's #ScienteaficABC spider family is ANAMIDAE! A brand spanking new family, having only been elevated to full family status in this hell year 2020. Formerly, these spiders were a tribe, then a subfamily, of the family Nemesiidae. (Images: iNat Creative Commons)

This family comprises 10 genera/104 species. These are mygalomorph spiders, an infraorder containing tarantulas, trapdoors, funnel webs, curtain webs & others characterised by their downward pointing chelicerae & fangs (& other things). (Chenistonia maculata by matthew_connors)

Native to Australia, 3 genera of this family (Aname, Chenistonia & Namea) are commonly called 'wishbone spiders' owing to the shape of the burrows they create. The silk-lined burrow is Y-shaped with one branch of the Y being longer than the other.

Read 12 tweets

🕷scienTEAfic🕷

@tea_francis

3 Dec

Bonus round! #ScienteaficABC. A small thread for this family AMMOXENIDAE! Why small? A few reasons. Firstly, it's a small family- 4 genera/18 species total, & secondly, they’re a specialised familiy so a broad summary should be pretty quick! (Images: Creative Commons, see end)

Ammoxenidae are commonly known as termite hunters. They are found in Africa & Australia, living on sand dunes, savannahs & bushland in both arid & tropical areas. They actively hunt for termites & when they're not hunting, they dig themselves into the sand. (Img: iNat cecileroux)

Once dug into the sand, they spin a silken retreat which is sticky on the outside so that sand grains stick to it & conceal it. They have adaptations to their chelicerae that enable them to dive face first into the sand and disappear from sight in seconds. (img: iNat peterwebb)

Read 9 tweets

🕷scienTEAfic🕷

@tea_francis

2 Dec

Next up in #ScienteaficABC, AGELENIDAE! This family comprises 87 genera, totalling 1307 species & has an almost cosmopolitan distribution making it a commonly encountered family. The pic shows a few examples of members & some common features. (Images: Wikimedia Commons & my own)

Agelenid spiders vary quite a lot in appearance from genus to genus, but generally can be identified by eye arrangement (see my awful pic), web type/habitat & shape of cephalothorax... though, as always, there are some that do not fall in line with this which makes things fun 😂

Some members of this family are commonly confused with other types of spider. Take this as an example... Agelenopsis sp. (grass spider) vs. Rabidosa rabida (wolf spider), both from Virginia. The most reliable way to tell them apart is their eyes & spinnerets. (Pics: Wikimedia)

Read 11 tweets

🕷scienTEAfic🕷

@tea_francis

1 Dec

Kicking off #ScienteaficABC, taking it from the top with Actinopodidae! This is a family of mygalomorph spiders (an infraorder of heavy bodied spiders with downward facing chelicerae), comprising just 3 genera- Actinopus, Missulena & Plesiolena. (All images: Wikimedia Commons).

Actinopodidae can be found in Australia and Central & South America. They are considered medically significant, which means their venom is potentially dangerous. Overall, they are heavy set, impressive looking spiders, usually with a stocky legs, large chelicerae & fangs.

Perhaps most recognisable of this family are Missulena spp. The mouse spiders! Found mostly in Australia, 1 of the 18 species is found in Chile. This is a male M. occatoria native to S. Australia. Females do not exhibit the bright red that the males do & tend to be heavier set.

Read 9 tweets

🕷scienTEAfic🕷

@tea_francis

29 Nov

This is the entrance to my Theraphosa apophysis’ burrow. It’s gone to ground to moult. This species possesses the most irritating urticating setae (specialised itchy hairs used for defense against predators etc) of all known tarantulas.

The spider has burrowed down in such a way that I have a window into its moult chamber. The whole thing is lined with silk, but most amazing of all is the protective measure it has taken to deter any would be attackers from disturbing it while it’s in its most vulnerable state.

See all that fluffy debris all over the spider (who is upside down here)? Those are its urticating setae. Prior to beginning its moult, it kicked them all over its silken moult mat & when it flipped on to its back, the result was it being covered in these hairs.

Read 4 tweets

🕷scienTEAfic🕷

@tea_francis

29 Nov

Throwback to last May. I found these two Clubiona terrestris wandering about on a planter. I only had one vial to hand so I risked putting them both in it together just to get them inside. As soon as they met, one piled on the other & I thought that was it, game over...

Then I saw that what I actually had was a male & female & he had pounced on her to mate with her. What was most remarkable about this was the total lack of any kind of courtship behaviour or caution in approaching her. He just got straight down to it as soon as he got a chance.

She didn’t stop wandering around for a while... almost like she hadn’t even realised what was happening either. Eventually, they settled & remained coupled like this for over an hour.

Read 4 tweets

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