— BugsInTheNews is a VIEWER-PARTICIPANT WEBSITE. This article by Jerry Cates and an anonymous contributor, published on 27 November 2011, was last revised on 8 July 2012. © Bugsinthenews Vol. 12:11(2).
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I received the following e-mail regarding the spider shown at left on 25 November 2011:
“Attached is a (photo of a) spider we found in Yoakum, Texas in a dirt pile inside a small funnel he built. The spider was a real shiny brown, and the closest thing I can find that looks like it is native to Australia!
The spider is about an inch and a half long, and appears to have 10 legs. Let me know if you could help me identify it. Thanks!”
I explained that this is a kind of trapdoor spider, probably one from a family of spiders that employ a variety of openings to the interiors of their nests, including what are called collardoors, foldingdoors, and turrets, and that two of the apparent 10 legs are actually pedipalps, so this specimen, like all other spiders, has only eight appendages that are true legs.
It is tentatively placed in the Antrodiaetidae family based on two primary considerations, namely (1) the observation of what appear to be several sclerotized patches, or tergites, on the anterodorsal abdomen (Coyle, 2005a), and (2) the relative shortness of the chelicerae, which project forward a distance approximately one-third the length of the carapace, while spiders in the Atypidae family, which are very similar, and also exhibit anterodorsal tergites, have chelicerae that project forward more than half the length of the carapace (Coyle, 2005b).
Not having the specimen in hand, it is impossible to speculate further. In fact, the tentative identification outlined above is quite possibly in error. It is based on the unproved speculation that the bright spots on the anterodorsal abdomen are tergites. In truth, those bright spots may actually represent nothing more than flash reflections from portions of an uninterrupted expanse of the abdomen’s dorsal surface (the resolution of the supplied image is insufficient to be certain). I hope that specimens of this spider will one day become available for microscopic study, though this particular spider was returned to the wild before I could request its retention for scientific study.
IMPORTANT NOTE: If you are reading this post because you have, in your possession, a spider similar to this one or to any of the trapdoor spiders described elsewhere on this website*, please consider holding the spider for scientific analysis. You may call Jerry at any time at 512-331-1111 for instructions on preserving the specimen for shipment to him; if he is not available to answer your call, leave a message and he should get back to you right away; you may also e-mail Jerry at email@example.com. Your e-mail will be viewable on his iPhone, and he should be able to get back to you right away, including by telephone if you include your phone number in the e-mail.
*The following posts on bugsinthenews.info feature trapdoor spiders in the Cyrtaucheniidae family:
- Cyrtaucheniidae (Myrmekiaphila, poss. new species): Trapdoor spider; Dave Peters, Cresson, TX–02.24.2011
The young lady who sent me the photo is not identified by name to protect her privacy. The spider was found in a dirt pile, behind the home of a relative of hers, who is presently out of town. As mentioned above, she let the spider loose in a nearby woods, after a spate of Internet sleuthing convinced her (rightly) that it did not pose a significant threat to her children.
My hope is that her relative will give me permission to visit that property at some date in the future to see if others of this species can be found for collection and analysis in the lab. That is particularly important regarding this species, if — as I suspect — it is a member of the Antrodiaetidae family. Although spiders in that family, which presently comprise three recognized genera, are widespread in North America, they are concentrated in the mid-eastern states of Tennessee, Kentucky, Virginia, and North Carolina, and in the western states of Oregon, Idaho, northern California, and Nevada, and are not commonly found in Texas.
For those interested in finding trapdoor and related spiders in wilderness settings, arachnologists have developed a number of easily made devices to be used for that purpose. For examples of such devices, the reader may wish to consult the paper written by Wagner, et al., 2003, cited and linked to in the list of references at the conclusion of this article. In Wagner’s paper, pit-fall traps and litter grab techniques are discussed in detail, along with diagrams showing pit-fall trap construction methods.
- Beccaloni, Jan. 2009. Arachnids. University of California Press, p. 56.
- Bond, Jason E. 1994. Seta-Spigot Homology and Silk Production in First Instar Antrodiaetus unicolor Spiderlings (Araneae: Antrodiaetidae). J. Arachnol., 22:19-22.
- Coyle, Frederick A. 1983 . Aerial dispersal by mygalomorph spiderlings (Araneae, Mygalomorphae) . J. Arachnol., 11 :283-286.
- Coyle, Frederick A. and Wendell R. Icenogle. 1994. Natural History of the Californian Trapdoor Spider Genus Aliatypus (Araneae, Antrodiaetidae). J. Arachnol., 22:225-255.
- Coyle, Frederick A. 2005a. Antrodieaetidae. Ubick, et al., Spiders of North America, an Identification Manual, p. 39-40.
- Coyle, Frederick A. 2005b. Atypidae. Ubick, et al., Spiders of North America, an Identification Manual, p. 41-42.
- Comstock, John Henry. 1914. The Spider Book. The New Nature Library, Vol. Seven, Part Two. Doubleday, Page & Company, p. 249.
- Emerton, James H. 1883. The Structure and Habits of Spiders. S. E. Cassino & Co, Publishers, pp. 44-51.
- Foelix, Rainer F. 1996. Biology of Spiders, Second Edition. Oxford University Press, pp. 267, 270.
- Gertsch, Willis J. 1979. American Spiders, Second Ed. Van Nostrand Reinhold Company, pp. 27, 121-122.
- Hendrixson, Brent E., and Jason E. Bond. 2005a. Testing species boundaries in the Antrodiaetus unicolor complex (Araneae: Mygalomorphae: Antrodiaetidae): “Paraphyly” and cryptic diversity. Molecular Phylogenetics and Evolution 36: 405–416.
- Hendrixson, Brent E., and Jason E. Bond. 2005b. Two sympatric species of Antrodiaetus from southwestern North Carolina (Araneae, Mygalomorphae, Antrodiaetidae). Zootaxa, 872: 1–19
- Kaston, B. J. 1978. How to know the spiders. McGraw Hill Company, pp. 40, 60-62.
- Levi, Herbert W. 1990. Spiders and Their Kin. Golden Press, New York, p. 23.
- Paquin, Pierre, and Nadine Dupérré. 2003. Guide d’identification des Araignées (Araneae) du Québec. Association des entomologistes amateurs du Québec, p. 50.
- Platnick, Norman I. 2011a. The World Spider Catalog, V. 12.0; FAM. ANTRODIAETIDAE Gertsch, in Comstock, 1940: 236. American Museum of Natural History.
- Vincent, Leonard S. 1993. The Natural History of the California Turret Spider Atypoides riversi (Araneae, Antrodiaetidae): Demographics, Growth Rates, Survivorship, and Longevity. J. Arachnol., 21:29-39.
- Wagner, James D., et al. 2003. Spatial Stratification in Litter Depth by Forest-Floor Spiders. J. Arachnol., 31:28-39.