Shore Crab (Carcinus maenas)

OTHER NAMES: Applejacks, Green Shore Crab, Green Crab, European Green Crab
Latin Etymology: Carcinus ("crab") maenas ("raving/frantic")

Young Shore Crab (Carcinus maenas) at Trevose Head - June 2011

Featured Subspecies: ?
Weight: up to 150g  /  Length: 9cm  /  Width: 21cm
UK STATUS NOT EVALUATED / IUCN Red List: Not Yet Evaluated 

For most people in the UK, this is the species of crab they are most likely to encounter in the wild - a dweller of shorelines commonly found in rockpools.  Originally from Northern Europe, they are an invasive species at locations of appropriate temperatures, and have established themselves on all continents except Asia and Antarctica.  They are edible, and fished commercially on a relatively small scale.

Related Species:
Order: Decapoda
Family: Portunidae
Genus: Carcinus
Subspecies: Unclear

 - Sighting Locations -

UNITED KINGDOM - A common resident of rocky coasts.

 - Seen at a number of coastal sites including Trevose Head,

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto .

Pink-fingered Vinegar Crab (Episesarma chentongense)

OTHER NAMES: Thai Vinegar Crab
Latin Etymology: Episesarma ("? grasping legs") chentongense (?)

Adult Pink-fingered Vinegar Crab (Episesarma chentongense) at Sungei Buloh, Singapore - February 2019

Featured Subspecies: ?
Weight: ?  /  Length: 5cm
NO UK STATUS / IUCN Red List: Not Yet Evaluated 

A mangrove specialist species, the vinegar crabs are a ground of medium-small sized species that have adapted to be able to climb up trees.  There are several species present in Singapore, identified by relatively subtle variation in patternations, primarily on the claws which unfortunately aren't visible in this picture.

Related Species:
Order: Decapoda
Family: Sesarmidae
Genus: Episesarma
SUBSPECIES: ?

 - Sighting Locations -

SINGAPORE - A locally common resident

 - CAMBODIA/SINGAPORE 2019 TRIP: Common at Sungei Buloh

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto .

Common Prawn (Palaemon serratus)

OTHER NAMES: Shrimp
Latin Etymology: Palaemon (afer a Greek sea God) serratus ("serrated")

Two young Common Prawn (Palaemon serratus) at Trevose Head, Cornwall - July 2019

Featured Subspecies: ?
Weight: ?  /  Length: 2.2-4.5cm
NO UK STATUS NOT EVALUATED / IUCN Red List: Not Yet Evaluated 

The Common Prawn is the generic shrimp species found in rockpools around the UK, and, indeed one of the most common species within those habitats.  It is semi transparent and can grow to over 10cm, making it the largest species of shrimp or prawn found in the UK.  The similar rockpool shrimp is also found in the UK.

Related Species:
Order: Malacostraca
Family: Palaemonidae
Genus: Palaemon
SUBSPECIES: ?

 - Sighting Locations -

UNITED KINGDOM - A widespread and common resident of rockpools.

 - Seen at Trevose Head and other locations with tidal rockpools around the country.

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto .

Perforated Barnacle (Balanus perforatus)

OTHER NAMES: N/A
Latin Etymology: Balanus ("acorn") perforatus ("pierced")

Adult Perforated Barnacles (Balanus perforatus) at Trevose Head, Cornwall - May 2012

Featured Subspecies: ?
Diamter: 30mm  /  Height: 30mm 
UK STATUS NOT EVALUATED / IUCN Red List: Not Yet Evaluated 

A distinctive species of large barnacle with a volcano like form, it is found in the Mediterranean, with South-East England being the Northerly limit of it's range at time of writing.  It favours lower shore rocks although it can also sometimes be found on the hull of ships.  As with other barnacles, it spends the first stage of it's life as a larvae called a nauplius, before shifting to a form known as a cyprid where it finds a spot to settle where it bonds itself permenantly to it's chosen location.  As it grows it will them get bigger.

Related Species:
Order: Sessilia
Family: Balanidae
Genus: Balanus
SUBSPECIES: ?

 - Sighting Locations -

UNITED KINGDOM - Common resident of rocky coasts in the South East of England and Wales.

 - Seen at Trevose Head and other coastal sites

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto .

Hoffman's Isopod* (Porcellio hoffmanseggi)

OTHER NAMES: * This species has no official English name, this name is a rough translation of the Latin one, but is entirely speculative.
Latin Etymology: Porcellio ("little pig") hoffmanseggi ("Hoffman's")

Adult Hoffman's Isopod* (Porcellio hoffmanseggi) at Italica, Spain - November 2011

Featured Subspecies: ?
Weight: ?  /  Length: < 5cm
ABSENT FROM UK / IUCN Red List: Not Yet Evaluated 

A large and distinctively "variegated" species of Woodlouse found primarily in Southern Spain with smaller populations in Portugal and North Africa.  It is much larger than the woodlouse species I see in the UK and are more tolerant of dry habitats as befiting a species from a warmer region.

Related Species:
Order: Isopoda
Family: Porcellionidae
Genus: Porcellio
SUBSPECIES: ?

 - Sighting Locations -

SPAIN - Spanish - ?
A fairly common resident in South-West Spain.

 - 2011 SEVILLE TRIP: Common at Italica 

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto .

Signal Crayfish (Pacifastacus leniusculus)

OTHER NAMES: N/A
Latin Etymology: Pacifastacus (?) leniusculus (?)

Adult Signal Crayfish (Pacifastacus leniusculus) at Berkeley, California - August 2022

Featured Subspecies: ?
Weight: g/kg  /  Length: 6-20cm
UK STATUS NOT EVALUATED/ IUCN Red List: Least Concern

Originally found in the North-West united states, the Signal Crayfish has via aquaculture become a major invasive species around the world including in California, Japan and the UK. They are an omnivore that feeds on detritus and can frequently outcompete local species, as well as being a carrier of crayfish plague which is far more lethal in other crayfish species.

Related Species:
Order: Decapoda
Family: Astacidae
Genus: Pacifastus
SUBSPECIES: P. l. leniusculus, P. l. trowbridgii, P. l. klamathensis 

 - Sighting Locations -

UNITED STATES 

Native in Oregon, Washington, Idaho, and Northern California, non-native in much of California
 - CALIFORNIA 2022 TRIP: Seen at Berkeley

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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