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Click on photos to enlarge.
Mollusks

Aberrations, Mutations & Twins

of Marine Life on the West Coast of North America


Bivalves
















Zirfaea pilsbryi, twinned siphon Zirfaea pilsbryi, twinned siphon Zirfaea pilsbryi, twinned siphon
Zirfaea pilsbryi - Rough Piddock
twinned exhalent siphon
all photographed in Rich Passage, Puget Sound, WA - 2012, 2012 & 2013 respectively
Tresus sp., twinned siphon
Tresus sp. - Horse Clam
twinned inhalent siphon
Rockaway Beach, Bainbridge Is., WA, 2007



Tresus sp., twinned siphon
Tresus sp. - Horse Clam
twinned inhalent siphon
Langley Tire Reef, Whidbey Is., WA, 2006














Zirfaea pilsbryi, twinned siphon
 












Flabellina verrucosa
Flabellina verrucosa
Red-gilled Nudibranch

merged rhinophore with two tips instead of two separate rhinophores
Rich Passage, Puget Sound, WA, 2013


Zirfaea pilsbryi - Rough Piddock
twinned inhalent siphon
Rich Passage, Puget Sound, WA, 2012


Nudibranchs













Mopalia kennerleyi Mopalia kennerleyi Mopalia kennerleyi
  San Francisco, CA, 1962         Kodiak, AK, 1981          Oak Bay, Puget Sound, WA, 2009
     6 plates instead of 8          6 plates instead of 8                    
7 plates instead of 8
Mopalia kennerleyi
Northern Hairy Chiton 




Anemones


Chitons

Metridium farcimen Metridium farcimen
Metridium farcimen - Giant Plumose Anemone
twins
left - Langley Harbor, Whidbey Island WA, 2008
right - Seahurst Park, Burien, WA, 2007




 
Lepidozona mertensii Lepidozona mertensii
     Neah Bay, WA, 1982          Sitka, AK, 1983         
Lepidozona mertensii  
Merten's Chiton
7 plates instead of 8











Metridium senile
Metridium senile
Short Plumose Anemone
twin
Penrose Point State Park, Puget Sound, WA, 2014

Stomphia didemon
Stomphia didemon
Swimming Anemone
twin
Flagpole Point, Hood Canal, WA, 2012



Lepidozona pectinulata
Lepidozona pectinulata 
9 plates instead of 8
Palos Verdes, CA, 1999

Cyanoplax hartwegii
Cyanoplax hartwegii
6 plates instead of 8
Puerto Santo Tomas, Baja Norte, 1982

Chaetopleura lanuginosa
Chaetopleura lanuginosa
6 plates instead of 8
Punta Banda, Baja Norte, 1982


 

Nuttallina californica
Nuttallina californica
California Nuttall's Chiton
9 plates instead of 8
La Jolla, CA, 1934

Tonicella lineata
Tonicella lineata (Wood, 1815)
Lined Chiton
9 plates instead of 8
Adak, Is., AK, 1966









Seastars
Dermasterias imbricata
Dermasterias imbricata
 Leather Star

 4 limbs instead of 5, replaced only one when two were lost or only started with four  
Point Hudson, Port Townsend, WA, 2013 

 Anthopleura elegantissima
Anthopleura elegantissima
Aggregating Anemone
twin
Freshwater Bay, WA, 2015


Mopalia ferreirai
Mopalia ferreirai  
7 plates instead of 8
Metlakatla, AK, 1990




Seastars will regrow limbs lost to predator attacks, but sometimes they regrow them in unusual ways.













Mopalia spectabilis
Mopalia spectabilis
Red-Flecked Mopalia
7 plates instead of 8
San Francisco, CA, 1982



Mopalia swanii
Mopalia swanii
Swan's Mopalia
7 plates instead of 8
Tacoma, WA, 1965




Dermasterias imbricata
Dermasterias imbricata
 Leather Star

7 limbs instead of 5
Twanoh State Park, Hood Canal, WA, 2011


Henricia leviuscula
Henricia leviuscula - Blood Star
4 limbs instead of 5
Freshwater Bay, Strait of Juan de Fuca, WA, 2014

Henricia pumila
Henricia pumila - Dwarf Mottled Henricia
6 limbs instead of 5
Deception Pass State Park, WA, 2008


























Dermasteria imbricata
Dermasterias imbricata
 Leather Star
6 limbs instead of 5
Ed's Fault, Discovery Bay, WA, 2015






Crabs



























Mediaster aequalis
Mediaster aequalis
Vermilion Star

4 limbs instead of 5
Pulali Point, Hood Canal, WA, 2015











Henricia leviuscula
Henricia leviuscula - Blood Star
6 limbs instead of 5
Klas Rocks, near Mats Mats Bay, WA, 2015
















Pteraster tesselatus
Pteraster tesselatus
Cushion Star

6 limbs instead of 5
Rich Passage, WA, 2010






























































Metacarcinus magister
Metacarcinus magister
Dungeness Crab
twinned claw
photographed at the University of Washington, no data available

Henricia leviuscula
Henricia leviuscula - Blood Star
6 limbs instead of 5
Freshwater Bay, Strait of Juan de Fuca, WA, 2014

Tresus sp., twinned siphon
Tresus sp. - Horse Clam
twinned inhalent siphon
Freshwater Bay, Strait of Juan de Fuca,
WA, 2014

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