''Lecthaylus'' is a genus of fossil sipunculid worms that lived between the

Cambrian The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...

and the Lower Carboniferous periods. Sipunculid worms are sedentary marine worms without any mineralised parts, and for this reason are very rare in the fossil record. ''Lecthaylus gregarius'' was described by the American geologist and palaentologist

Stuart Weller Stuart Weller (26 December 1870, Maine, New York – 1927) was an American paleontologist and geologist. Weller studied geology and paleontology at Cornell University with bachelor's degree in 1894 and at Yale University with Ph.D. in 1901. Begin ...

in 1925 from the Silurian strata near Chicago. Professor Weller described this worm, which was abundant in the deposits, as being "manifestly related to '' Serpulites'' or '' Conularia''; however, further examination by Sharat Kumar Roy determined that this was not the case, and that the worms were more likely members of

Sipunculoidea The Sipuncula or Sipunculida (common names sipunculid worms or peanut worms) is a class containing about 162 species of unsegmented marine annelid worms. The name ''Sipuncula'' is from the genus name ''Sipunculus'', and comes from the Latin '' ...

, and this is now the accepted position. A related species of sipunculan was discovered in 2007 in the Granton Shrimp Bed near Edinburgh and was first described by L. A. Muir and J. P. Botting, who placed it in the genus ''Lecthaylus''.

References

Sipunculans Prehistoric protostome genera {{Paleo-protostome-stub