Family Nuculanidae, Nuculidae,
Yoldiidae, & Glycymerididae
Nuculanidae Nuculana hamata(Carpenter, 1864)Hooked Nutclamsubtidal, 30-550m size to 12mm
northern Mexico to southern Alaska
It is small and is distinguished by
its very long, curved rostrum.
(previous names - Leda hamata, L.h. limata)
Nuculana minuta Müller, 1776Minute Nutclam
subtidal, 4 - 1900m size to 18mm
Panarctic and circumboreal, to southern California in the
eastern Pacific, to Japan in the western Pacific, to Maine
and Scotland in the Atlantic
It is very small and is distinguished by its truncated rostrum,
widely spaced commarginal ribs and shiny yellow to dark
(previous names - Arca minuta, Leda minuta [various forms])
Nuculidae Acila castrensis (Hinds, 1843)Divaricate Nutclam
subtidal, 5-400m size to 20mmnorthern Mexico to the Bering Sea and off the Kamchatka peninsulaIt is small and distinguished by its divaricate sculpture. The periostracum is dull and light olive
to dark brown. Although not found intertidally, it is
very common to find subtidally in the northwest.
(synonyms - Nucula castrensis,
N. divaricata, Acila beringiana)
Glycymeris septentrionalis (Middendorff, 1849) live specimenWestern Bittersweet
to 400m northern Mexico to southern
Alaska size to 45mm
It can be found
intertidally at good low tides. It has a chalky white shell with brown flecks
and maculations. There are numerous teeth on the
margin and on either side of the hinge. The hinge size and
shell sculpture can vary widely. The interior is often yellow
with brown stains.
(synonyms - Pectunculus septentrionalis, Glycymeris subobsoleta, Glycymeris profunda)
Yoldiidae Megayoldia thraciaeformis(Storer, 1838)Broad Yoldia
subtidal, 25-760m size to 65mm
central California to Bering Sea; Japan
It is distinguished by a quadrate shape
and broadly truncated posterior end.
(synonyms - Nucula thraceaeformis,
Yoldia seminuda Dall, 1871Oblique-Lined Yoldia
subtidal, 15-375m size to 40mm
southern California to Bering Sea;
northern Japan to Sea of Okhotsk
It has an elongated, thin shell.
The periostracum is adherent and
shiny yellow to dark brown.
(synonyms - Nucula arctica,
Ennucula tenuis (Montagu, 1808)Smooth Nutclamsubtidal, 10-900m size to 17mmcircumboreal and Arctic ocean, reaches south to southern California, Florida, Mediterranean, and northern Japan
The periostracum is light olive to dark brown and the shell is smooth.
(previous name - Nucula tenuis)
This page last revised: 8-16-2011
Yoldia myalis (Couthouy, 1838)Oval Yoldia
subtidal, 20-165m size to 30mm
northern Washington to Bering Sea; Maine to
Hudson Bay and also Sea of Okhotsk
The posterior end is broadly rounded. The dark
brown periostracum may be dull or silky.
(synonyms - Nucula myalis, Yoldia vancouvernesis)
Click on photo to enlarge. Scale line in photo equals 1cm unless otherwise specified.
* Species which are commonly encountered on the beach.