Barnacle is entirely marine with the genus Amphibalanus is the most common group occupy almost all marine environment, especially the intertidal area. Segara Anakan is a unique mangrove ecosystem in a lagoon estuary located in Cilacap on the southwestern border of Central Java with West Java. Mangrove in this area is also a typical habitat for Amphibalanus spp barnacles. This research aimed to determine the species identity, and the evolutionary relationship among Amphibalaninaes found in Segara Anakan Cilacap based on morphological and molecular characteristics. This research was a survey with purposive random sampling technique applied to collect samples. The species determination and identification was conducted based on the soft parts (body) and the hard parts (shell) and described based on the morphological characteristic. Molecular identification used a mitochondrial COI genetic marker, and targeted region of DNA was obtained by PCR technique using Folmer LCOI and HCOI primer pair for comparative analysis isolated from muscle tissue. Morphological phylogenetic reconstruction was completed using the PAUP program, and the phylogenetic analysis was conducted using MEGA 5 software. The reconstructed cladogram suggested the morphotype of Amphibalanus isolate B10 belong to the genus Fistulobalanus but distinguishable with other known species. The phylogram also suggested the morphotype B10 is the sister species of Fistulobalanus albicostatus.

Morphotype; Teritip; Amphibalanus; Segara Anakan