Belongs within: Vinctiplicata.
The Priapulida are free-living, unsegmented marine worms with a muscular, eversible proboscis.
Characters (Land 1970): Vermiform, unsegmented animals. Body cylindrical, bilaterally symmetrical with strong tendency to radial symmetry, divisible in at least two regions: abdomen and introvert, the latter serving as locomotory organ and invaginable into the former. Ectoderm a columnar epithelium, covered with strong chitinous cuticula; cutícula subject to moult throughout life. Mouth terminal, giving entry to armed and muscular pharynx, the anterior part of which is eversible. Intestine straight and simple, lined with columnar epithelium; anus at posterior end of abdomen. Single, spacious coelom, filled with coelomic fluid with free coelomocytes containing haemerythrin; lined with peritoneum. Musculature mainly consisting of dermomuscular layers of circular and longitudinal muscles and system of strong retractors; part of muscles striated. Central nervous system located in epidermis, consisting of peribuccal ring and ventral nerve cord terminating in preanal ganglion. Sense-organs of different kinds occuring all over body; eyes absent. Circulatory system absent. Sexual reproduction only; sexes separate. One pair of urogenital organs, attached to body wall by mesenterium; excretory organs of solenocytic protonephridial type; urogenital ducts with separate pores near anus. Cilia completely absent; flagellated cells occuring in urogenital system. Embryological development incompletely known; bilateral cleavage; blastula and gastrula stages present. Larvae free-living, not ciliated; abdomen enclosed in relatively strongly cuticularized lorica; metamorphosis to postlarval stage.
Priapulida [Priapula, Priapulimorpha, Priapuloidea, Subactinozoaires]
| i. s.: ‘Conularia’ tenuicostata Branson 1938 [=Mesoconularia tenuicostata]BF86b
|--TubiluchidaeS-P86
| |--Meiopriapulus Morse 1981S-P86
| | `--M. fijiensis Morse 1981S-P86
| `--Tubiluchus van der Land 1968S-P86
| |--*T. corallicola van der Land 1968TS03
| |--T. arcticus Adrianov, Malakhov et al. 1988TS03
| |--T. australensis Land 1985TS03
| |--T. philippinensis Land 1985TS03
| |--T. remanei Land 1982TS03
| |--T. troglodytes Todaro & Shirley 2003TS03
| `--T. vanuatensis Adrianov & Malakhov 1991TS03
`--+--MaccabeusDD04
| |--M. cirratusMS98
| `--M. tentaculatusMS98
`--Priapulidae [Priapulacea, Priapulea, Priapulidea]L70
|--Halicryptus von Siebold 1849DD04, L70 [=Halikryptus (l. c.)L70]
| |--*H. spinulosus von Siebold 1849 [incl. H. spinosus var. multidentatus Zenger 1870]L70
| `--H. higginsiTS03
`--+--Priapulites konecniorum Schram 1973DD04, SHB15
`--+--Priapulopsis Koren & Danielssen 1875DD04, L70 [=Priapuloides Koren & Danielssen 1877L70]
| |--*P. bicaudatus (Danielssen 1868) (see below for synonymy)L70
| `--P. australis (de Guerne 1886) [=Priapuloides australis]L70
`--+--Acanthopriapulus van der Land 1970DD04, L70
| `--*A. horridus (Théel 1911) [=Priapulus horridus]L70
`--Priapulus de Lamarck 1816DD04, L70 [=Priapula (l. c.)L70; incl. Priapus Linnaeus 1758 (nom. rej.)DB07]
|--*P. caudatus de Lamarck 1816 (see below for synonymy)L70
|--P. australisSHB15
`--P. tuberculatospinosus Baird 1868 (see below for synonymy)L70
*Priapulopsis bicaudatus (Danielssen 1868) [=Priapulus bicaudatus, Priapuloides bicaudatus, Priapulopsis typica Koren & Danielsen 1875, Priapuloides typicus; incl. Priapulus atlantisi Sanders & Hessler 1962, Priapulopsis atlantisi]L70
Priapulus caudatus de Lamarck 1816 [=Priapula caudata (l. c.), Priapula (l. c.) caudatus, Priapus humanus Linnaeus 1758, Priapulus humanus, Holothuria priapus Linnaeus 1767, Priapula (l. c.) priapus, Priapulus priapus, Priapulus vulgaris Cuvier 1836; incl. Priapulus brevicaudatus Ehlers 1861, Priapulus glandifer Ehlers 1861, Priapulus hibernicus McCoy 1845, Lacazia hibernica, Priapulus intermedius Lenz 1878, Priapulus tuberculatospinosus japonicus Murina & Starobogatov 1961, Priapulus caudatus kristinebergensis Hérubel 1904, Priapulus caudatus mofjordensis Hérubel 1904, Priapulus multidentatus Möbius 1873, Priapulus profundus Sanders & Hessler 1962, Priapulus pygmaeus Verrill 1880, Priapulus pygmaens (l. c.)]L70
Priapulus tuberculatospinosus Baird 1868 [=P. caudatus tuberculatospinosus; incl. P. abyssorum Menzies 1959, P. tuberculatospinosus abyssorum, P. caudatus var. antarcticus Michaelsen 1889, P. tuberculatospinosus bahiensis Olivier, Rapoport & García 1961, P. humanus var. antarcticus, P. fuegensis Lahille 1899, P. tuberculatospinosus var. fuegensis]L70
*Type species of generic name indicated
References
[BF86] Babcock, L. E., & R. M. Feldmann. 1986. Devonian and Mississippian conulariids of North America. Part B. Paraconularia, Reticulaconularia, new genus, and organisms rejected from Conulariida. Annals of Carnegie Museum 55 (16): 411–479.
[DB07] Daly, M., M. R. Brugler, P. Cartwright, A. G. Collins, M. N. Dawson, D. G. Fautin, S. C. France, C. S. McFadden, D. M. Opresko, E. Rodriguez, S. L. Romano & J. L. Stake. 2007. The phylum Cnidaria: a review of phylogenetic patterns and diversity 300 years after Linnaeus. Zootaxa 1668: 127–182.
[DD04] Dong, X-P., P. C. J. Donoghue, H. Cheng & J.-B. Liu. 2004. Fossil embryos from the Middle and Late Cambrian period of Hunan, south China. Nature 427: 237–240.
[L70] Land, J. van der. 1970. Systematics, zoogeography, and ecology of the Priapulida. Zoologische Verhandelingen 112: 1–118.
[MS98] Margulis, L., & K. V. Schwartz. 1998. Five Kingdoms: An Illustrated Guide to the Phyla of Life on Earth 3rd ed. W. H. Freeman and Company: New York.
[S-P86] Salvini-Plawen, L. v. 1986. Priapulida. In: Botosaneanu, L. (ed.) Stygofauna Mundi: A Faunistic, Distributional, and Ecological Synthesis of the World Fauna inhabiting Subterranean Waters (including the Marine Interstitial) pp. 122–124. E. J. Brill/Dr W. Backhuys: Leiden.
[SHB15] Smith, M. R., T. H. P. Harvey & N. J. Butterfield. 2015. The macro- and microfossil record of the Cambrian priapulid Ottoia. Palaeontology 58 (4): 705–721.
[TS03] Todaro, M. A., & T. C. Shirley. 2003. A new meiobenthic priapulid (Priapulida, Tubiluchidae) from a Mediterranean submarine cave. Italian Journal of Zoology 70: 79–87.