Arachnids at Los Tuxtlas


students collecting Los Tuxtlas 14 July 2014 B sml

Students collecting around the field station.

I spent an enjoyable week of this July at the UNAM Los Tuxtlas field station in Vera Cruz, Mexico, sitting in on a field course and taking a macrophotography holiday. The course was on the taxonomy and biology of Salticidae jumping spiders, and was run by Wayne Maddison from the University of British Columbia (Canada) and Gustavo Ruiz from the Universidade Federal do Pará (Brazil).


Seventeen undergraduate and graduate students from Mexico, Central America, and South America were eager vessels for the instructors’ salticidological wisdom.

classroom Los Tuxtlas 16 July 2014

Classroom at Los Tuxtlas.

Jumping spiders were abundant and conspicuous at Los Tuxtlas.  Quite a contrast from the situation in Alberta, where hunting salticids requires a vast amount of patience and belief in divine intervention. Here is a small selection of the beautiful jumping spiders we saw.

big male Freya regia on leaf Los Tuxtlas 14 July 2014 sml

Despite being named for the Norse goddess of love, this Freya is all man.

Corythalia on wall Los Tuxtlas 16 July 2014 sml

One of about a dozen species of Corythalia from Los Tuxtlas.

Lyssomanes male Los Tuxtlas 17 July 2014 sml

Male Lyssomanes maddisoni court via semaphore.

There was a great diversity of other families of spiders at Los Tuxtlas. Large wandering spiders of the genus Cupiennius (Ctenidae) were everywhere. Less common, but a great treat for me as I hadn’t seen them since I lived in Australia more than a decade ago, were two-tailed spiders (Hersiliidae). Neither is as flashy as most salticids, but they have a subtle beauty of their own.

ctenid Cupiennius on wall UNAM Los Tuxtlas 14 July 2014 trimmed sml

Cupiennius on retaining wall.

two-tailed spider Hersiliidae Los Tuxtlas 17 July 2014 sml

Two-tailed spider (Hersiliidae)

In addition to Araneae, I saw many other orders/superorders of arachnids at the field station including Acariformes, Opiliones, Palpigradi, Parasitiformes, Pseudoscorpiones, Ricinuleida, Schizomida and Scorpiones. The only terrestrial ones I didn’t see were Solfugida, Amblypygi and Uropygi, though the latter two were no doubt there. I was particularly excited to photograph live ricinuleids. At one point they were thought to be the sister group to mites because they shared with the Acari a 6-legged larval stage, among other things. Molecules say otherwise, though, both with regard to the relationship between mites and ricinuleids and the monophyly of mites themselves. Unfortunately, the post-larval ricinuleid got tangled up in residual spider webbing from the vial it was held in, and was too hobbled to walk naturally.

trombidioid Los Tuxtlas 15 July 2014passalid venter with mites Los Tuxtlas 15 July 2014 sml

gonyleptid sl opilionid Los Tuxtlas 14 July 2014scorpion prob Chactidae 16 July 2014 sml

ricinuleid larva and HPs pinkie finger Los Tuxtlas 16 July 2014 smlricinuleid adult unfortunately webbed up Los Tuxtlas 16 July 2014 A

Non-spider arachnids, starting at top left: acariform mite, parasitiform and possibly also acariform mites on the venter of a passalid beetle, opilionid, scorpion, 6-legged larval ricinuleid and my pinkie finger, post-larval ricinuleid.


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