Trapdoor Spiders in Texas

BugsInTheNews is a VIEWER-PARTICIPANT WEBSITE. This article by Jerry Cates, first published on 13 January 2011, was revised last on 10 January 2013. © Bugsinthenews Vol. 12:01(06)


Cyrtaucheniidae (Eucteniza spp.): Wafer Trapdoor Spider, closeup of legs I and II showing ventral tibiae megaspines; Stacey, Austin TX--01.09.2011

001. Ventral tibiae megaspines on legs I and II

Of 16 families presently recognized in the infraorder Mygalomorphae, many are comprised strictly of trapdoor spiders.

Their familial and generic names are long and difficult to pronounce. But if you investigate their origins you will discover a rich history.

For example, the etymology of the familial name Euctenizidae, as well as the generic name Eucteniza (pron. yook-ten-IZ-uh) is a consequence of the fact that these spiders were once grouped as a sub-genus under what became, at least for a time, the super-genus Cteniza.

This change was made by the Austrian arachnologist Anton Ausserer (5 July 1843 — 20 July 1889) in 1875, when he declared it necessary to divide Latrielle’s Cteniza into two separate sub-genre, which he named Cteniza and Eucteniza.

Thus, the Greek word ευ, which means “well, good,” was applied as a prefix to the generic name Cteniza, primarily as a morphological device to distinguish it from its sister sub-genus, Cteniza. Later the sub-genus Eucteniza was raised to full generic status by the French aracnologist Eugène Simon (30 April 1848 — 17 November 1924).

The Eucteniza are distinguished from other spiders in the Euctenizidae family by, among other things, the fact that the Eucteniza possess large mid-ventral megaspines on the tibiae of both legs I and II (see the photo at the head of this article).

The genus Cteniza had earlier been named, in 1829, by the French arthropodologist Pierre André Latreille (20 November 1762 — 6 February 1833).

Latrielle applied the Greek verb κτενιζω, (ch)tenizo, which in the infinitive means “to comb,” and added a feminine nominative ending, thus creating a noun.

The reference is to the rastellum, a rake-like process on the chelicerae which is characteristic to both the Cteniza (now the Ctenizidae family) and the Cyrtaucheniidae (which now includes Eucteniza. along with 18 other genera).

The genus Cteniza was raised to family level (the Ctenizidae) by the Swedish arachnologist Tord Tamerlan Teodor Thorell (3 May 1830 — 22 December 1901), in 1887.

Mygalomorph Spider: Marvin W., Kempner, TX--11.12.08: Chelicerae, ventral view, fangs extended

002. Mygalomorph Spider Chelicerae

The following posts on feature spiders in the infraorder Mygalomorphae:



  • Kingdom Animalia (an-uh-MAYHL-yuh) — first described in 1758 by the Swedish taxonomist Carolus Linnaeus (1707 – 1778), using the Latin word animal = “a living being,” from the Latin word anima = “vital breath”, to refer to multicellular, eukaryotic organisms whose body plans become fixed during development, some of which undergo additional processes of metamorphosis later in their lives; most of which are motile, and thus exhibit spontaneous and independent movements; and all of whom are heterotrophs that feed by ingesting other organisms or their products;
  • Phylum Arthropoda (ahr-THROPP-uh-duh) first described in 1829 by the French zoologist Pierre André Latreille (1762 – 1833), using the two Greek roots αρθρον (AR-thron) = jointed + ποδ (pawd) = foot, in an obvious reference to animals with jointed feet, but in the more narrow context of the invertebrates, which have segmented bodies as well as jointed appendages;
  • Subphylum Chelicerata (Kuh-liss-uh-RAH-tah) — first described in 1901 by the German zoologist Richard Heymons (1867 – 1943) using the Greek noun χηλη (KEY-lay) = a claw, talon, or hoof + the Greek noun κερας (SAIR-as) = an animal’s horn + the Latin suffix ata — which by convention is suffixed to the names of animal subdivisions — to refer to animals that have specialized appendages before the mouth that they use in feeding, capturing and securing prey and that — in the case of spiders — are further equipped to inject venom and digestive agents into their prey; 
  • Class Arachnida (uh-RAKH-nuh-duh) first described in 1812 by the French naturalist and zoologist Jean Léopold Nicolas Frédéric Cuvier (1769 – 1832), usually referred to as Georges Cuvier, using the Greek noun αραχης (uh-RAH-kes) = a spider, in reference to all eight-legged arthropods, including such disparate animals as ticks, mites, scorpions, harvestmen, solpugids, and spiders;
  • Order Araneae (uh-RAY-neh-ee) — first described in 1757 by the Swedish entomologist and arachnologist Carl Alexander Clerck (1709 – 1765), who used the Latin word aranea = a spider or a spider’s web, to refer to eight legged arthropods that spin webs;
  • Suborder Opisthothelae (oh-PIS-thoh-THEE-lee) — first described in 1990 by the American arachnologists Richard C. Brusca and Gary J. Brusca, who used the Greek words οπισθεν (oh-PIS-thehn) = behind, at the back, yet to come + θηλη (THEE-lee) = nipple or teat, to distinguish this grouping of spiders from the more primitive spiders in the suborder Mesothelae, in that certain characters (e.g., tergite plates, ganglia in the abdomen, and — in particular, inasmuch as the suborder name is a direct reference thereto — median-positioned spinnerets) of the latter are absent in the former; thus spiders in this suborder have spinnerets positioned at the hindmost portion of the abdomen;
  • Infraorder Mygalomorphae (my-GAL-oh-MOHR-fee) — spiders with paraxial chelicerae and two pairs of book lungs, as in the more primitive Mesothelae, but without the latter’s tergite plates and most of the latter’s abdominal ganglia, and having their spinnerets positioned at the abdomen’s hindmost portion rather than mid-ventrally as in the Mesothelae; presently comprised of sixteen families:
    • Atypidae (Thorell 1870) — 3 genera, 49 species (Platnick WSCv13.5); commonly known as purseweb spiders; 8-27 mm, yellow-brown to dark purple-black in color; the legs of male specimens of Sphodros rufipes (Latrielle 1829) and S. fitchi (Gertsch & Platnick 1980) are bright orange-red; both of these species, and no others from this family, have been found in Texas (Dean 2012);
    • Antrodiaetidae (Gertsch 1940) — 2 genera, 33 species (Platnick WSCv13.5); commonly known as foldingdoor, collardoor, or turret spiders (Antrodiaetus), and trapdoor spiders (Aliatypus); 6-26 mm, tan to chestnut brown, with one or more tergites on the anterodorsal abdomen; live in burrows with a flexible collar, a rigid turret, or a trapdoor at the mouth; no species in this family is known to be found in Texas (Dean 2012);
    • Mecicobothriidae (Holmberg 1882) — 4 genera, 9 species (Platnick WSCv13.5); no common name; mygalomorphs with two tergites on their anterodorsal abdomen (these sclerotized patches may be fused); build sheet webs with silk tubes from sheet to ground that lead into hiding places under terrestrial objects; no species in this family is known to be found in Texas (Dean 2012);
    • Hexathelidae (Simon 1892) — 12 genera, 112 species (Platnick WSCv13.5); no species in this family is known to be found in Texas (Dean 2012);
    • Dipluridae (Simon 1889) — 24 genera, 179 species (Platnick WSCv13.5); commonly known as mygalomorph funnelweb spiders; 3.5-17 mm, pale tan to purple-brown in color; thoracic furrow in the form of a short longitudinal groove or a shallow pit or rounded depression; one species, Euagrus chisoseus Gertsch 1939, is known to be found in Texas;
    • Cyrtaucheniidae (Simon 1889) — 10 genera, 102 species (Platnick WSCv13.5); no species in this family is known to be found in Texas (Dean 2012);
    • Ctenizidae (Thorell 1887) — 9 genera, 128 species (Platnick WSCv13.5); no common name; 10-30 mm or more in length, tan, dark chestnut brown, and black in color; the females lack scopulae, but are equipped with a number of robust lateral digging spines on their pedipalps, as well as on the tarsus, metatarsus, and tibia of legs I and II; carapace generally glabrous, with few distinct spines; thoracic furrow is transverse, typically very deep and procurved; burrows are covered with a thick cork-type trapdoor for all genera, except Cyclosmia Ausserer 1871, which have wafer-type trapdoors; 7 species in the genus Ummidia are known to be found in Texas (Dean 2012);
    • Euctenizidae (Raven 1985) — 7 genera, 33 species (Platnick WSCv13.5); one species in the genus Entychides, two species in the genus Eucteniza, and one species in the genus Myrmekiaphilia are known to be found in Texas (Dean 2012);
    • Idiopidae (Simon 1889) — 22 genera, 314 species (Platnick WSCv13.5); no species in this family is known to be found in Texas (Dean 2012);
    • Actinopodidae (Simon 1892) — 3 genera, 40 species (Platnick WSCv13.5); no species in this family is known to be found in Texas (Dean 2012);
    • Migidae (Simon 1889) — 10 genera, 91 species (Platnick WSCv13.5); no species in this family is known to be found in Texas (Dean 2012);
    • Nemesiidae (Simon 1889) — 43 genera, 364 species (Platnick WSCv13.5); 16-30 mm, golden brown to dark gray, generally concolorous but sometimes with an indistinct chevron pattern on the dorsal abdomen; no species in this family is known to be found in Texas (Dean 2012);
    • Microstigmatidae (Roewer 1942) — 7 genera, 16 species (Platnick WSCv13.5); no species in this family is known to be found in Texas (Dean 2012);
    • Barychelidae (Simon 1889) — 44 genera, 307 species (Platnick WSCv13.5); no species in this family is known to be found in Texas (Dean 2012);
    • Theraphosidae (Thorell 1869) — 124 genera, 946 species (Platnick WSCv13.5); 18 species, all in the genus Aphonopelma, are known to be found in Texas (Dean 2012);
    • Paratropididae (Simon 1889) — 4 genera, 8 species (Platnick WSCv13.5); no species in this family is known to be found in Texas (Dean 2012);




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