The Larval Stages of Lithotrya dorsalis (Ellis & Solander, 1786): A Burrowing Thoracican Barnacle

Lithotrya dorsalis is a member of the only genus of thoracican barnacles known to burrow and is widely distributed throughout the tropical western Atlantic. It occurs primarily in high energy intertidal environments. L. dorsalis undergoes the typical thoracican larval sequence. Six naupliar stages are followed by the cyprid stage. These larvae were reared in the laboratory and their stages are described for the first time. Newly hatched stage I nauplii are typically 360 μm in total length; larval size increases to 1100 μm by the 6th instar. The most distinguishing characteristic of Lihtotrya dorsalis nauplii is the presence of unusually long, spinulated posterior shield spines in stages IV through VI. Complete larval development (stage I nauplius to cyprid) averaged 18 days and ranged from 12 to 23 days. Scanning electron micrograph descriptions of the cyprid cuticle of this animal, showing a unique striated appearance, are also included.