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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


T. democratica oozoid musculature consists of 5circular muscles in complete rings around the body (M1 – M5). A minorinterruption may occur in Muscle 5 on the ventral side. Fusing also occursbetween muscles 1 to 3 and 4 to 5 along the mid dorsal region (fig. 1). Musculature also exists within the incurrent and excurrent siphons.

T.democraticans rely on their body’s musculature for a number of fundamental functions such as movement, feeding, and sense. 5 large complete circular muscles surround the body and when required sequentially contract in conjunction with muscles controlling the siphons, resulting in propulsion of the animal through the water (Lacalli and Holland, 1998). As a filter feeding species, T.democratica rely solely on propulsion through the water for food extraction,thus highlighting the importance on the muscle structure of the organism. Contraction of the body muscles occurs in a coordinated fashion with all 5 muscles contraction simultaneously, generating maximal force with the least effort. Muscles located around the mouth and excurrent siphons allow individuals to control both the magnitude and direction of water flow through the body. By alternating the flow of water through the incurrent and or excurrent siphon individuals can control the direction in which they move, i.e.forward propulsion or rearward propulsion (Lacalli and Holland, 1998,Heron, 1972).