Carcinus aestuarii

Carcinus aestuarii
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Decapoda
Infraorder:	Brachyura
Family:	Portunidae
Genus:	Carcinus
Species:	C. aestuarii
Binomial name
Carcinus aestuarii Nardo, 1847 [1]
Synonyms
Carcinus mediterraneus Czerniavsky, 1884 Carcinus maenas aestuarii Nardo, 1847 Portunus menoides Rafinesque, 1817

Carcinus aestuarii is a littoral crab, native to the Mediterranean Sea. It bears some similarities to Carcinus maenas and was sometimes considered to be a subspecies thereof, rather than a species in its own right, but a molecular biological study using the COI gene found the difference between the two taxa to be substantial, supporting their status as separate species.^[2]. The two taxa can be visually distinguished by the front of the carapace, between the eyes, which is short and toothed in C. maenas but longer and smoother in C. aestuarii. Also, the gonopods of C. aestuarii are straight and parallel, whereas those of C. maenas are curved.^[3]

Whereas C. maenas has invaded many shorelines throughout the world, C. aestuarii has only been implicated in one invasion; the coastline of Japan has been invaded by either C. aestuarii or a hybrid of C. aestuarii and C. maenas.^[4]

References

1. ^ Peter K. L. Ng, Danièle Guinot & Peter J. F. Davie (2008). "Systema Brachyurorum: Part I. An annotated checklist of extant Brachyuran crabs of the world" (PDF). Raffles Bulletin of Zoology 17: 1–286. http://rmbr.nus.edu.sg/rbz/biblio/s17/s17rbz.pdf. 
2. ^ J. Roman & S. R. Palumbi (2004). "A global invader at home: population structure of the green crab, Carcinus maenas, in Europe" (PDF). Molecular Ecology 13 (10): 2891–2898. doi:10.1111/j.1365-294X.2004.02255.x. PMID 15367106. http://joeroman.com/images/roman&palumbi.eu.04.pdf. 
3. ^ S. B. Yamada & L. Hauck (2001). "Field identification of the European green crab species: Carcinus maenas and Carcinus aestuarii". Journal of Shellfish Research 20 (3): 905–909. http://www.sgnis.org/publicat/papers/yamahauc.pdf. 
4. ^ T. J. Carlton & A. N. Cohen (2003). "Episodic global dispersal in shallow water marine organisms: the case history of the European shore crabs Carcinus maenas and C. aestuarii". Journal of Biogeography 30 (12): 1809–1820. doi:10.1111/j.1365-2699.2003.00962.x.