''Ptilometra australis'', the passion flower feather star, is a
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
crinoid
Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are ...
. It is native to the coasts of southeastern Australia where it is found on reefs, in estuaries and bays at depths down to about .
Description
The passion flower feather star is a robust crinoid with a diameter of about when fully extended. It has eighteen to twenty jointed arms which can be coiled up when the animal is not feeding. These are attached to a cup-shaped body or
calyx. The arms are edged by feathery appendages known as pinnules. Each pinnule has rows of
tube feet
Tube feet (technically podia) are small active tubular projections on the oral face of an echinoderm, whether the arms of a starfish, or the undersides of sea urchins, sand dollars and sea cucumbers; they are more discreet though present on br ...
on either side of a central
ambulacral
Ambulacral is a term typically used in the context of anatomical parts of the phylum Echinodermata or class Asteroidea and Edrioasteroidea. Echinoderms can have ambulacral parts that include ossicles, plates, spines, and suckers. For example, sea ...
groove lined with
cilia. This groove is continuous with the central groove on the arm which leads to the mouth at the centre of the calyx. The aboral (lower) surface of the crinoid has a number of hooked appendages called
cirri which grip onto the
substrate, which may be a rock, a
sponge
Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate throug ...
, a
coral
Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and ...
or
sea fan
Alcyonacea, or soft corals, are an order of corals. In addition to the fleshy soft corals, the order Alcyonacea now contains all species previously known as "gorgonian corals", that produce a more or less hard skeleton, though quite different ...
. The colour of this crinoid is usually some shade of red,
though subjection to organic solvents yields a complex mixture of
pigments
A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compoun ...
whose components can be separated using
chromatography
In chemical analysis, chromatography is a laboratory technique for the separation of a mixture into its components. The mixture is dissolved in a fluid solvent (gas or liquid) called the ''mobile phase'', which carries it through a system ( ...
.
Distribution and habitat
The passion flower feather star is native to the coasts of southeastern Australia down to depths of about . Its range extends from
Masthead Island in
Queensland
)
, nickname = Sunshine State
, image_map = Queensland in Australia.svg
, map_caption = Location of Queensland in Australia
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, establishe ...
and the mouth of the
Clarence River in
New South Wales
)
, nickname =
, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
to
Port Philip Bay
Port Phillip ( Kulin: ''Narm-Narm'') or Port Phillip Bay is a horsehead-shaped enclosed bay on the central coast of southern Victoria, Australia. The bay opens into the Bass Strait via a short, narrow channel known as The Rip, and is comp ...
in
Victoria
Victoria most commonly refers to:
* Victoria (Australia), a state of the Commonwealth of Australia
* Victoria, British Columbia, provincial capital of British Columbia, Canada
* Victoria (mythology), Roman goddess of Victory
* Victoria, Seychelle ...
.
[ It is found on rocks and rubble in sheltered bays, in estuaries and on reefs.][
]
Biology
The passion flower feather star is a filter feeder. It catches plankton and suspended particles of detritus with the tube feet on the pinnules. These feet are covered with sticky mucus
Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It ...
that traps the food particles and then roll it into balls before moving them into the ambulacral groove, where cilia propel the stream of mucus towards the mouth.[
]
References
{{Taxonbar, from=Q2449473
Comatulida
Animals described in 1843
Fauna of the Pacific Ocean