Today is a sad day, with a heavy heart I have decided to retire my laptop ‘Tosh’ after nine years of service. As such one last task remains for the valiant machine, to write and then post this issue of Impurest’s Guide to Animals. This issue features a creature of Lovecraftian terror, one who opposes the Narwhal (last week’s issue) in a popular meme. Hope you guys enjoy…
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Issue #63 – Pioma cthulhu
Kingdom – Animalia
Phylum – Arthropoda
Class – Arachnida
Order – Aranae
Family – Pimoidae
Genus – Pioma
Species - cthulhu
RelatedSpecies – Pioma cthulhu is one of twenty one cave spiders found in the genus Pioma (1)
Range – Pioma cthulhu is found in redwood forests in the Sonoma and Mendocino counties of Western California
All Hail Cthulhu
Pioma Cthulhu is a small spider, which has a cephalothorax length of only three to six millimetres, and a leg span of up to a few centimetres. The body of the male is a dull brown, and the larger female is more of a rusty red colour. Being a former cave dweller, the species is nocturnal, but can be found during the day in man-made structures such as cabins, as well as in hollowed out redwood trees. The main feature of this species are the long legs, in the males case they are covered with long hairs, that gave rise to the word Pioma, a Gosiute Native American word for ‘big legs (2)’.
Like the vast majority of spiders, P. cthulhu is a carnivore, feeding off insects that live in the redwood holes it calls home. This species, like others of its genus weaves sheet like webs, to aid in the capture of prey. While few large predators would be able to breach P.cthulu’s tree fortresses, arthropods and amphibians are a different story, and the species is probably predated on by larger spiders and arboreal salamanders.
Reproduction in P. cthulhu is at current, undocumented, but it can be assumed to be similar to other members of the genus Pioma. It is noted that the females of the group, carry their egg sacs around longer than other spiders of a similar size, possibly as a behaviour retained from when the species was found only in caves, where resources were scarce.
Ecology 101: A Guide to Environmental Mechanics #6 – Cave Biota
The word ‘troglodyte’ is often one that is misused to label species found in caves, despite the meaning only referring to humans (Homo sapiens sapiens). A more correct term, for cave dwelling animals is troglofauna, and even then the term is misleading, as not all troglofauna is found in caves. For further clarity troglofauna can be split into three designations (3);
Trogloxene – A species that visits caves, but is not complete any of its life-cycle in them
Troglophile – A species that completes most of its life-cycle in a cave, but can be found outside subterranean habitats
Troglobite – A species that lives its entire life-cycle in caves
As such, species commonly associated with caves such as bats, bears, swallows etc., are actually trogloxenes, they visit caves, may even spend prolonged periods of time in them, but they can survive quite comfortably in other environments as well. In addition, the ‘troglodytes’ mentioned earlier are also trogloxenes since they have no real adaptions to living full time in caves. In fact all birds and mammals that are associated with caves are classified as such, the energy deficit found in caves simply can’t support these groups for long.
Troglophiles, on the other hand are species evolving towards becoming full-time troglobites (or occasionally evolving for life on the surface such as Pioma cthuluhu). These species will begin to display features such as reduced eyes, elongated legs and paler skin, as competition for resources is reduced, as is the potential for predation. Over time those species that survive, will become fully fledged troglobites, unable to survive outside their subterranean homes.
Because of this extreme specialisation, troglofauna is rarely found outside a few local caves, making these species unique and variable to changes in their environments. That said the pressures of cave living, can lead to convergent evolutions, with troglofauna resembling unrelated species found entire continents away (4). An example of this is the Olm (Proteus anguis) and the Texan Blind Salamander (Eurycea rathbuni), both of whom have evolved reduced eyes and legs and external gills to aid them in cave living. Due to reduced range and genetic diversity, troglofauna is vulnerable to change, and are used as indicators to tell how healthy the surrounding environment is.
Bibliography
2. Hormiga, G.; Buckle, D. J.; Scharff, N. (2005). "Nanoa, an enigmatic new genus of pimoid spiders from western North America (Pimoidae, Araneae". Zoological Journal of the Linnean Society145 (2): 249–262
3. Ormiga, G.; Buckle, D. J.; Scharff, N. (2005). "Nanoa, an enigmatic new genus of pimoid spiders from western North America (Pimoidae, Araneae)". Zoological Journal of the Linnean Society145 (2): 249–262
4. Thomas C. Barr, Jr. & John R. Holsinger (1985). "Speciation in cave faunas". Annual Review of Ecology and Systematics16: 313–337
Picture Credits
1. - https://dinnshenchas.files.wordpress.com/2014/11/pimoa-cthulhu.jpg.jpg
3. - http://www.mountainsbeyond.org/Nature/Reptiles/images/Snakes/CaveRacer.jpg
4. -https://cyntaur23.files.wordpress.com/2010/07/ceuthbg.gif
And as we say farewell to ‘Tosh’ and the creepy ‘Cthulhu Spider’ we can rest assured that a new issue will be arriving next week. But until then critic, comment and suggest a species you want to see as well as check out Impurest’s Bestiary of Past Issues.
Many Thanks
Impurest Cheese
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