Chthamalus fragilis

{{short description|Species of crustacean}}

{{Speciesbox

| image = Chthamalus fragilis on a leaf of Spartina alterniflora. Photo by Yihui Zhang.jpg

| image_alt = "Chthamalus fragilis" on a leaf of "Spartina alterniflora"

| image_caption = Chthamalus fragilis on a leaf of Spartina alterniflora

| genus = Chthamalus

| parent_authority = Foster, 1980

| species = fragilis

| authority = (Darwin, 1854){{cite web|title=Chthamalus fragilis Darwin, 1854|url=https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=89593|publisher=The Integrated Taxonomic Information System|accessdate=6 July 2015}}

}}

Chthamalus fragilis is a small gray barnacle found in the upper intertidal zone of the northwestern Atlantic Ocean, from approximately Cape Cod southward to Florida and into the Caribbean and Gulf of Mexico. It is also commonly known as little grey barnacle. The species is believed to have been distributed only as far northward as North Carolina or Virginia until the late 1800s, when it was noticed along the Massachusetts coast. The species may have expanded its range naturally or been introduced to New England through anthropogenic activities.{{cite journal|title=Phylogeographic structure and northward range expansion in the barnacle Chthamalus fragilis|journal=PeerJ|date=April 30, 2015|volume=3|page=e926|doi=10.7717/peerj.926|pmid=25945315|pmc=4419548 | last1 = Govindarajan | first1 = AF | last2 = Bukša | first2 = F | last3 = Bockrath | first3 = K | last4 = Wares | first4 = JP | last5 = Pineda | first5 = J |doi-access=free }} Chthamalus fragilis is unusual in that it often recruits to stems of Spartina alterniflora.{{cite journal|title=Factors, at different scales, affecting the distribution of species of the genus Chthamalus Ranzani (Cirripedia, Balanomorpha, Chthamaloidea|journal=Journal of Experimental Marine Biology and Ecology|volume=392|issue=1–2|pages=46–64|doi=10.1016/J.Jembe.2010.04.010|last1=O'Riordan|first1=RM|last2=Power|first2=AM|last3=Myers|first3=AA|year=2010}}