Echiura

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Spiralia
Cladus: Lophotrochozoa
Phylum: Annelida
Classis: Polychaeta
Subclassis: Echiura
Ordines (3): Echiuroidea - Heteromyota - Xenopneusta

• Biseswar, R. 2009: The geographic distribution of echiurans in the Atlantic Ocean (Phylum Echiura). Zootaxa, 2222: 17–30. Abstract & excerpt
• Biseswar, R. 2010: Zoogeography of the echiuran fauna of the Indo-West Pacific Ocean (Phylum: Echiura). Zootaxa, 2727: 21–33. Preview
• Biseswar, R. 2012. Zoogeography of the echiuran fauna of the East Pacific Ocean (Phylum: Echiura). Zootaxa 3479: 69–76. Preview Reference page. 
• Chipman, A.D. 2008: Annelids step forward. Evolution & development, 10(2): 141–142.
• Dean, H.K. et al. 2010: Sipunculans and Echiurans of Isla del Coco (Cocos Island), Costa Rica. Zootaxa, 2557: 60–68. Preview
• Hessling, R.; Westheide, W. 2002: Are Echiura derived from a segmented ancestor? Immunohistochemical analysis of the nervous system in developmental stages of Bonellia viridis. Journal of morphology, 252(2): 100–113.
• McHugh, D. 1997: Molecular evidence that echiurans and pogonophorans are derived annelids. PNAS, 94: 8006–8009.
• Nishikawa, T. 1998: Nomenclatural remarks on the family-group names of the phylum Echiura. Proceedings of the Biological Society of Washington, 111: 249–256.
• Rouse, G.W.; Pleijel, F. 2007: Annelida. Pp. 245-264 in: Zhang, Z.-Q. & Shear, W.A. (eds.) Linnaeus tercentenary: progress in invertebrate taxonomy. Zootaxa, 1668: 1–766. PDF
• Struck, T.H.; Schult, N.; Kusen, T.; Hickman, E.; Bleidorn, C.; McHugh, D.; Halanych, K.M. 2007: Annelid phylogeny and the status of Sipuncula and Echiura. BMC evolutionary biology, 7: 57. [1]

• Catalogue of Life: 2012 Annual Checklist
• Echiura in the World Register of Marine Species

For more multimedia, look at Echiura on Wikimedia Commons.