silhouette of a sea star, harmless animals

Starfish are composed of a central disc from which arms sprout in pentaradial symmetry. Most starfish have 5 arms, but some have more or fewer. Some starfish have shown differing numbers of limbs within a single species. The mouth is located underneath the starfish, on its ventral surface. The spiny upper surface is called the aboral or dorsal surface. On the aboral surface there is a structure called the madreporite, a small white spot located slightly off-center on the central disc which acts as a water filter and supplies the starfish's water vascular system with water to move. Porcellanasteridae employ additional cribriform organs used to generate current in the burrows made by these infaunal starfish.

While having their own basic body plan, starfish radiate diversely in shapes and colors, the morphology differing between each species. A starfish may have dense rows of spines as a means of protection, or it may have no spines at all. Ranging from nearly pentagonal (example: Indo-pacific cushion star, Culcita novaeguineae) to gracile stars like those of the Zoroaster genus.

Surrounding the spines on the surface of the starfish are small white objects known as pedicellariae. There are large numbers of these pedicellariae on the external body which serve to prevent encrusting organisms from colonizing the starfish. The radial canal which is across each arm of the starfish has tooth-like structures called ampullae, which surround the radial canal.

On the end of each arm or ray there is a microscopic eye which allows the starfish to see, although it only allows it to see light and dark, which is useful to see movement.

Patterns including mosaic-like tiles formed by ossicles, stripes, interconnecting net between spines, pustules with bright colors, mottles or spots. These mainly serve as camouflage or warning coloration which is displayed by many marine animals as a means of protection against predation. Several types of toxins and secondary metabolites have been extracted from several species of starfish. Research into the efficacy of these compounds for possible pharmacological or industrial use occurs worldwide.

Direction Walk 0.06 km or 1 mins south west from last photo
Location Diani Beach, East Africa, Kenya, Africa
Info F 5.6 1/250 ISO 100 with Canon EOS DIGITAL REBEL XTi
Itinerary . feeling: neutral, slighly upbeat
Country Kenya State East Africa
City Diani Beach Weather Sunny and hot
Continent Africa Day Diani Beach
Activity glass boat Tour GAP (Great Adventure People)
Feeling mild upbeat User Comment
Date 2007:10:10 10:12:49 Make Canon
Model Canon EOS DIGITAL REBEL XTi Width 3888
Height 2592 Flash Off, Did not fire
Focal 56.0 mm Exposure 1/250
F Number 5.6 ISO 100
White Bal. Auto Program Aperture-priority AE
Compensation 0 Hyperfocal 30.16 m
Latitude -4.34126666666667 Longitude 39.57345
Altitude 0.6000000238 m File Size 6.5 MB
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