There are only sixteen known living species of priapulid worms.

Halicryptus is the sole genus of its class of priapulid worms, and grows to great size.

Fossil priapulid worms.

Species in this genus infect marine priapulid worms and terrestrial and freshwater gastropods.

The delicate approach can also recover fragments of animals: scales from priapulid worms, Wiwaxia sclerites, and arthropod feeding parts, for example.

Priapus (priapulid worms & anemones)

Despite this lack of fossil evidence, burrows produced by modern priapulid worms are almost identical to Treptichnus, suggesting a close anatomical relationship between the trace-maker and modern priapulids.

In 1977, Conway Morris recognized among forms that Walcott had scattered across three phyla (as polychaetes, crustaceans, and echinoderms) six or seven genera of priapulid worms.

For example, the research suggests Markuelia has closest affinity to priapulid worms, and is adjacent to the evolutionary branching of Priapulida, Nematoda and Arthropoda.

Priapulida (priapulid or penis worms) are a phylum of marine worms.

Priapulida (priapulid worms or penis worms, from Gr.

If little penis worms ruled the sea, I have no confidence that Australopithecus would ever have walked erect on the savannas of Africa.

The group of worm-like marine burrowing animals known as the Priapulidea, literally "penis worms", also derives its name from Priapus.

We need no longer talk of subjects peripheral to our parochial concerns--of alternative worlds crowded with little penis worms, of marrelliform arthropods and no mosquitoes, of fearsome anomalocarids gobbling fishes.

But would it really matter if all the replays of the Burgess Shale produced their unrealized opposites--and we inhabited a world of wiwaxiids, a sea floor littered with little penis worms, and forests full of phororhacids?

Their closest relatives are thought to be the Kinorhyncha and Priapulida, with whom they share some characteristics.

The present phylum Priapulida also has a deuterostomic development, despite being otherwise placed within the protostomes.

In addition, Priapulida, Entoprocta, and Tardigrada are sometimes included.

Smaller phyla related to them are the Kinorhyncha, Priapulida, and Loricifera.

The mouth cone ("everted pharynx") of a possible new species of Meiopriapulus, a marine worm in the Priapulida, bears pharyngeal teeth.

The Priapulida form a small phylum of ten genera or so in today's oceans, but they dominated the worm fauna of the Burgess Shale.

Scalidophora is a group of marine pseudocoelomate invertebrates, consisting of the three phyla Kinorhyncha, Priapulida, and Loricifera.

Gephyrea is a now-dismantled taxon that was considered to be a class of annulated worms, containing the three modern phyla Echiura, Sipuncula, and Priapulida.

Most protostome phyla outside the Lophotrochozoa are members of Ecdysozoa ("animals that molt"), which include Arthropoda, Nematoda and Priapulida.

The Vinctiplicata is a clade of Scalidophora uniting the Loricifera and the Priapulida, and representing the sister group to the Kinorhyncha.

For example, the research suggests Markuelia has closest affinity to priapulid worms, and is adjacent to the evolutionary branching of Priapulida, Nematoda and Arthropoda.

The Ecdysozoa include the following phyla: Arthropoda, Onychophora, Tardigrada, Kinorhyncha, Priapulida, Loricifera, Nematoda and Nematomorpha.

As well as many papers on Harpacticoida up to 1965, and many papers on Tanaidacea throughout his life, Lang also published on Priapulida and Kinorhyncha, and a single paper on isopod crustaceans.