| 词条 | Pacifastacus fortis |
| 释义 |
| image = Shasta crayfish.jpg | status = CR | status_system = IUCN3.1 | regnum = Animalia | phylum = Arthropoda | subphylum = Crustacea | classis = Malacostraca | ordo = Decapoda | familia = Astacidae | genus = Pacifastacus | species = P. fortis | binomial = Pacifastacus fortis | binomial_authority = (Faxon, 1914) }} Pacifastacus fortis (known as the Shasta crayfish or placid crayfish) is an endangered crayfish species endemic to Shasta County, California, where it is found only in isolated spots on the Pit River and Fall River Mills. Description and ecologyP. fortis is thick and stocky, with relatively heavy chelae. It is usually dark brown dorsally with bright orange areas on its underside. It grows about 2-4 inches long. It lives in cold, clear, rocky areas of the mountain rivers, and feeds on the slime coating the rocks. The animal requires a constant, steady, and untainted flow of fresh water to survive. ConservationPacifastacus fortis is listed as a critically endangered species on the IUCN Red List,[1] and an endangered species under the Endangered Species Act.[2] It has always had a very small native range, and that range has been significantly fragmented by such human activities as damming, mining, and agriculture. The signal crayfish, a recently introduced species, has outcompeted P. fortis in much of its range. The Pit River Fish Hatchery was closed to protect this species. References1. ^{{Cite journal | author = D. Johnson | author2 = C. A. Taylor | author3 = G. A. Schuster | author4 = J. Cordeiro | author5 = T. Jones | title = Pacifastacus fortis | journal = The IUCN Red List of Threatened Species | volume = 2010 | page = e.T15866A5246459 | publisher = IUCN | date = 2010 | url = http://www.iucnredlist.org/details/15866/0 | doi = 10.2305/IUCN.UK.2010-3.RLTS.T15866A5246459.en | access-date = 9 January 2018}} 2. ^{{FWS profile |spcode=K01U |sci=Pacifastacus fortis |name=Shasta crayfish |date=October 6, 2010}} External links
8 : Astacidae|Crustaceans of the United States|Endemic fauna of California|Freshwater crustaceans of North America|Crustaceans described in 1914|Critically endangered fauna of California|Taxa named by Walter Faxon|ESA endangered species |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。