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Thalia democratica


Brook Anderson (2013)     


Fact Sheet



Physical Description

Sexual Form

Asexual Form


Biogeographical Location

Feeding Ecology

Life History & Behaviour

Asexual Reproduction

Sexual Reproduction

Anatomy & Physiology

Sensory System

Muscular System

Feeding Structures and Function

Evolution & Systematics

Conservation & Threats

References & Links


Thalia democratica is a gelatinous, free-living species of salp belonging to the subphylum Urochordata (Heron, 1972). It is an opportunistic filter feeding species which periodically occurs in continental shelf water globally during times of high oceanic productivity (Kremer, 2002Henschke et al., 2011, Vargas and Madin, 2004). T. democratica, is the smallest of the four most common salp species, and is an extremely successful colonizer, which, during times of high productivity can competitively exclude other dominant zooplankton species such as copepods (Henschke et al., 2013, Henschke et al., 2011, Vargas and Madin, 2004). Such high success is said to be due to a combination of short generation times, high reproductive output per reproductive individual, and highly efficient feeding strategies (Henschke et al., 2013, Henschke et al., 2011). The lifecycle of T. democratica is complex and involves an alternation between asexual and sexual generations. This strategy has proved highly successful by allowing the maximal reproductive output while maintaining genetic diversity (Henschke et al., 2011, Henschke, 2009). On T. democratica species collected on Heron Island, Australia, I have anatomically assessed the asexual mode of reproduction to further understand the development of clones within the asexual unit. I have identified the general region within the asexual unit from whichthe clones differentiate and begin development. I have also documented the progression of clones from this stage to the point at which they are ready to be released into the water column.