Chthamalus dalli
Pilsbry, 1916
Little Brown Barnacle
Chthamalus dalli is a small intertidal barnacle found along the North Pacific coast. It occupies the high intertidal zone, where it tolerates extended aerial exposure. Research shows its reproductive output is sensitive to , with crowded individuals producing fewer per unit body mass.
Pronunciation
How to pronounce Chthamalus dalli: /kθəˈmæləs ˈdælaɪ/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
Distinguished from other Pacific coast barnacles by its small size and preference for the upper intertidal zone. Smaller than Semibalanus balanoides and Balanus glandula, with which it co-occurs. Shell becomes columnar under crowded conditions versus conical when uncrowded.
Habitat
High intertidal rocky shores; tolerates prolonged desiccation and wave exposure.
Distribution
North Pacific coast from Alaska to San Diego, California.
Diet
, capturing plankton and particles from seawater when submerged.
Life Cycle
Hermaphroditic; internal via extendable penis; in mantle cavity; releases planktonic nauplius that develop through cyprid stage before settlement.
Behavior
as ; permanently attached to rocky substrate. Exhibits -dependent plasticity in shell form and reproductive investment.
Ecological Role
Primary consumer and ; contributes to intertidal structure; serves as for intertidal .
Similar Taxa
- Chthamalus fissusOverlapping range and ; distinguished by shell plate and genetic differences
- Balanus glandulaCo-occurs in lower intertidal; larger size and different shell structure
- Semibalanus balanoidesSimilar ecological studies conducted; differs in reproductive response to crowding
More Details
Crowding effects
Research demonstrates that C. dalli individuals in crowded, columnar growth forms produce smaller clutches per unit somatic tissue weight compared to uncrowded, conical individuals. This contrasts with Semibalanus balanoides, which shows increased when crowded, and Balanus glandula, which shows the opposite pattern to C. dalli.