Dysdera crocata; Koch, 1838

This is probably a record - photograph and upload on the same day.

Today, at work, I was pleasantly surprised by an unexpected guest.

Several of my co-workers were not-so-pleasantly surprised, and wanted to squish the guest. I not-so-delicately reminded them that arachnophobia is in no way the fault - or the problem - of the spider, and took her outside, where she rewarded me with this:

Female. Photographed in Bosham, West Sussex, UK, in April 2014 (today) using Olympus E-420 DSLR, Zuiko 40-150mm lens and 3 KOOD magnifiers.

That isn't an aggressive pose, by the way, but a defensive pose adopted when I loomed in closer than she liked with the camera. And while it's perhaps not the best way to endear her to an audience which is on the fence, those rather extraordinary chelicerae are relevant, because this is the (recently cosmopolitan) European Woodlouse Spider,

Dysdera crocata

Koch, 1838

  
As you might have guessed, she feeds upon woodlice and other comparably crusty creatures. Those formidable fangs are what allow her to bite through the calcium carbonate coating of the average woodlouse, or the chitin of a millipede or even - if you were so incautious as to poke her in the face - the somewhat softer keratin of human skin.

If you do - as quite a few people have - find yourself inciting a woodlouse spider to bite, don't panic  - the recorded effects on humans are in the region of nettle and honeybee stings (see the Natural History Museum's bite records here). 

With that, then, let's explore her taxonomy: 

- Dysderinae         

-  Dysderidae          

- Dysderoidea           

- Haplogynae             

- Araneoclada             

See also Phrynarachne rugosa, Hyllus argyrotoxus, Enoplognatha ovata, Argiope bruennichi, Pardosa amentata  and Alopecosa barbipes. 

- Neocribellatae           

- Araneomorphae           

- Opisthothelae                

- Araneae                         

- Megoperculata                  

- Micrura                              

- Arachnida                             

See also Dicranopalpus ramosus.

- Chelicerata                            

- Arthropoda                            

See also Ligia oceanica, Eremoides bicristatus, Hagenomyia tristis, Dichtha inflata, Oedemera nobilis, Otiorhynchus atroapterus,Malachius bipustulatus , Phyllobius pomaceus, Cheilomenes lunata, Melolontha melolontha, Neojulodis vittipennis, Demetrias atricapillus, Anthia fornasinii, Lophyra cf. differens, Synagris proserpina, Vespula germanica, Astata tropicalis, Anthophora furcata, Andrena nigroaenea, Zebronia phenice, Crambus pascuella, Nemophora degeerella, Sphinx ligustri, Laelia robusta, Acada biseriata, Metisella willemi, Anthocharis cardamines, Papilio demodocus, Panorpa germanica, Chloromyia formosa, Senaspis haemorrhoa, Helophilus pendulus, Episyrphus balteatus, Metadon inermis, Diasemopsis meigenii, Dolichotachina caudata, Megistocera filipes, Pephricus, Grypocoris stysi, Ranatra, Anoplocnemis curvipes, Idolomantis dentifrons, Sibylla pretiosa, Tettigonia viridissima, Stictogryllacris punctata, Enyaliopsis, Humbe tenuicornis, Lobosceliana loboscelis, Cyathosternum prehensile, Heteropternis thoracica, Pseudothericles jallae, Enallagma cyathigerum, Pseudagrion hageni, Lestinogomphus angustus and Rhyothemis semihyalina. 

- Ecdysozoa                               

- Protostomia                              

See also Burtoa nilotica.

- Nephrozoa                                  

See also Caprimulgus pectoralis, Tockus alboterminatus, Larus argentatus, Sterna hirundo, Burhinus vermiculatus, Troglodytes troglodytes, Megaceryle maxima, Ardea goliath, Chalcophaps indica, Stigmatopelia senegalensis, Lygodactylus capensis, Thelotornis capensis, Zootoca vivipara, Trachylepis varia, Trachylepis striata wahlbergi, Hipposideros vittatus, Syncerus caffer, Rana temporaria, Breviceps poweri, Chiromantis xerampelina and Synchiropus splendidus. 

- Bilateralia                                     

- Eumetazoa                                     

- Animalia                                          

- Eukaryota                                         

There are two species of Dysdera present in the UK, both of which can occasionally be found indoors - much more frequently in the case of today's distinctly synanthropic (does well near humans) guest. They're not too readily distinguished, as colour characters are often unreliable, but the presence of one external character can readily rule out Dysdera erythrina [although its absence cannot, unfortunately for the spiders, rule out D. crocata, and so dissection is sometimes necessary if perfect identification is vital to the survival of the human race]. Behold;

Although not at their most visible in this shot, our lovely lady has a couple (three, actually, on the circled thigh - two is usual) of small, black bristles on the dorsal surface (top side) of her fourth femur (thigh bit). So - despite having colouring suggestive of D. erythrina, and being in a region where both are known, we've got a known specimen.

Which is nice, don't you think?

And with that, that really is all, folks.

An excellent starting point for UK spiders is the Spider (and harvestman) Recording Scheme - link in name. With pictures of probably a majority of species, maps of known records, and absolutely stunning graphs and pie-charts (I love statistics. I didn't always. But now I do. Thank you, Dr. Tom Reader, for showing me the light. If I'd only realised my love before I handed in my dissertation three years ago...).