''Cryptophialus minutus'' is a species of

barnacle Barnacles are arthropods of the subclass (taxonomy), subclass Cirripedia in the subphylum Crustacean, Crustacea. They are related to crabs and lobsters, with similar Nauplius (larva), nauplius larvae. Barnacles are exclusively marine invertebra ...

. One cluster in particular, dubbed Mr. Arthrobalanus, is notable for being the impetus for

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English Natural history#Before 1900, naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all speci ...

's "Cirripedia project" and obsession with barnacles.

Description

''Cryptophialus minutus'' is a small (2 mm) cirripede that has no shell. It mechanically burrows into the shell of host organisms such as '' Concholepas peruviana''. Unlike many barnacle species, ''C. minutus'' is not hermaphroditic. Males are much reduced, one-tenth the size of females, and missing features such as a head and stomach. Males serve little purpose besides reproduction.

Mr. Arthrobalanus

Mr. Arthrobalanus was the name given to a colony of ''C. minutus'' that Darwin collected off the coast of

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

in 1835. He referred to it as his "little monster" as he was vexxed by the taxonomy of the species. He published his initial examination in 1846. When Darwin requested other barnacle specimens from research institutions to compare to Mr. Anthrobalanus, he realized the existing work on the subject was insufficient. As a result, Darwin decided to circumscribe the broader taxa. Invested deeply in the work, he continued his efforts against the recommendation of his doctors after his health began to fail. He finally returned to Mr. Anthrobalanus in 1853. It was formally described in 1854.

References

{{Taxonbar, from=Q13503023 Barnacles Crustaceans of Chile Crustaceans described in 1854 Taxa named by Charles Darwin