Mygalomorphae

Introduction

The mygalomorph spiders, including trapdoor spiders, tarantulas and their kin, is a moderately diverse group that includes more than 2,600 described species, classified in over 300 genera and 15 families. The group is a diverse assemblage of relatively large, long-lived (15-30 years), ground dwelling spiders that build a diverse array of silk constructs used for prey capture, shelter, and protection (Coyle 1986).  Considered an ancient monophyletic group (Coddington & Levi 1991; Platnick & Gertsch 1976; Raven 1985), mygalomorphs retain several characteristics that are considered primitive for spiders (e.g., two pairs of book lungs, simple spinning structures, etc). Many mygalomorph taxa are dispersal-limited and regionally-endemic, and have long been favorites of biogeographers (e.g., Griswold & Ledford 2001; Platnick 1981).  Mygalomorph lineages have a deep evolutionary history, as reflected in a rich fossil fauna that extends back to the lower Triassic (Selden & Gall 1992), with fossil representatives of several families dating to the mid-Cretaceous (see Eskov & Zonshtein 1990; Penney et al. 2003; Selden 2002).  Recent molecular clock analyses suggest intra-familial divergences date to the Cretaceous  (Hendrixson & Bond 2007), and inter-familial divergences may be as old as 300 Ma (Ayoub et al. 2007). 

References

Ayoub NA, Garb JE, Hedin M, Hayashi CY. 2007. Utility of the nuclear protein-coding gene, elongation factor-1 gamma (EF-1γ), for spider systematics, emphasizing family level relationships of tarantulas and their kin (Araneae: Mygalomorphae). Molecular Phylogenetics and Evolution 42, 394-409.

Bond, J.E., Hedin, M., 2006. A total evidence assessment of the phylogeny of North American euctenizine trapdoor spiders (Araneae, Mygalomorphae, Cyrtaucheniidae) using Bayesian inference. Mol. Phylogen. Evol., in revision.

Coddington, J. A. and H. W. Levi. 1991. Systematics and evolution of spiders (Araneae). Annual Review of Ecology and Systematics 22:565-592.

Coyle, F.A., 1986. The role of silk in prey capture by nonaraneomorph spiders. In: Shear, W.A. (Ed.), Spiders: Webs, Behavior and Evolution. Stanford University Press, Stanford. pp. 269-305.

Dippenaar-Schoeman AS. 2002. Baboon and Trapdoor Spiders of Southern Africa: An Identification Manual Agricultural Research Council, Pretoria, South Africa.

Eskov, K., Zonshtein, S., 1990. First Mesozoic mygalomorph spiders from the Lower Cretaceous of Siberia and Mongolia, with notes on the system and evolution of the infraorder Mygalomorphae (Chelicerata:Araneae). N. Jb. Geol. Paläont. Abh. 178, 325-368.

Goloboff, P.A., 1993. A reanalysis of mygalomorph spider families (Araneae). Am. Mus. Novit. 3056, 1-32.

Griswold, C. Ledford, J., 2001. A monograph of the migid trap-door spiders of Madagascar, with a phylogeny of world genera (Araneae, Mygalomorphae, Migidae). Occ. Pap. Calif. Acad. Sci. 151, 1-120.

Hedin, M and J. E. Bond. 2006. Molecular phylogenetics of the spider infraorder Mygalomorphae using nuclear rRNA genes (18S and 28S): Conflict and agreement with the current system of classification. Molecular Phylogenetics and Evolution, 41, 454-471.

Hendrixson BE, Bond JE (2007) Molecular phylogeny and biogeography of an ancient Holarctic lineage of mygalomorph spiders (Araneae: Antrodiaetidae: Antrodiaetus). Molecular Phylogenetics and Evolution

Penney, D., Wheater, C.P., Selden, P.A., 2003. Resistance of spiders to Cretaceous-Tertiary extinction events. Evolution 57, 2599-2607.

Platnick, N.I., 1977. The hypochiloid spiders: A cladistic analysis, with notes on the Atypoidea (Arachnida, Araneae). Am. Mus. Nov. 2627, 1-23.

Platnick, N.I., 1981. Spider biogeography: past, present, and future. Revue Arachnologique 3, 85-96.

Platnick, N.I., Gertsch, W.J., 1976. The suborders of spiders: A cladistic analysis (Arachnida, Araneae). Am. Mus. Nov. 2607, 1-15.

Raven, R.J., 1985. The spider infraorder Mygalomorphae (Araneae): cladistics and systematics. Bull. Am. Mus. Nat. Hist. 182, 1-180.

Selden PA (2002) First British Mesozoic spider, from Cretaceous amber of the Isle of Wight. Palaeontology 45, 973-983.

Selden, P.A., Gall, J.-C., 1992. A Triassic Mygalomorph spider from the northern Vosges, France. Paleontology 35, 211-235.

Information on the Internet

• Mygalomorph Phylogeny & Evolution Page
• Mygal Information from Bugguide
• Nearctic Spider Database
• World Spider Catalog
• African Trapdoor Spiders