Larval development of the intertidal barnacles Jehlius cirratus and Notochthamalus scabrosus (Cirripedia : Chthamalidae) under laboratory conditions

Larvae of the common intertidal chthamalid barnacles Jehlius cirratus and N otochthamalus scabrosus were obtained from mature adults collected in centr al and northern Chile and cultivated in the laboratory at temperatures typi cal of the conditions encountered by larvae in these regions. Morphological and developmental descriptions of the six naupliar stages and the cyprid s tage of both species are given. Both species clearly present the general pa ttern of development for chthamalids, in which the structural characters of the cephalic shield and abdominal process, in conjunction with the utiliza tion of the alphabetical setation formula for antennae, facilitate the iden tification and differentiation between larval stages. The average time of n aupliar larval development of J. cirratus and N. scabrosus in sea-water tem perature ranging 15-18 degrees C was 31 and 37 days, while larvae cultivate d in temperatures ranging 18-20 degrees C completed naupliar development af ter 13 and 20.2 days, respectively. This represents a 58% and 45.5% reducti on in naupliar development time with a three-degree increase in mean sea wa ter temperature for J. cirratus and N. scabrosus, respectively. The develop ment time from cyprid until settlement and metamorphosis of N. scabrosus la sted between 9 and 11 days, depending on the temperature, while cyprid deve lopment for J. cirratus lasted 8 days at 18-20 degrees C. The average sizes of the naupliar and cyprid stages were similar between the species at both temperature ranges. Although the increased temperature reduced the time of larval development, it did not significantly affect larval sizes.