The word "Ommateum" is often misspelled due to its complex spelling. It refers to the compound eye of certain arthropods, such as insects and crustaceans. The correct spelling is /ˌɒməˈtiːəm/, with emphasis on the second syllable. The first syllable is pronounced like "ahm," followed by the schwa sound in the second syllable, and ending with the "tee-uhm" sound in the final syllable. While the spelling may be difficult, proper pronunciation can help communicate clearly when discussing these fascinating arthropod eyes.
Ommateum refers to an organ or structure commonly found in arthropods, particularly in members of the phylum Arthropoda, such as insects and crustaceans. Specifically, it is an eye that is composed of multiple facets or lenses, also known as ommatidia. These ommatidia work together to enable the organism to perceive its surroundings visually.
Each individual ommatidium in an ommateum functions as a discrete eye of its own. It consists of a refractive lens, a light-detecting photoreceptor structure known as a retinula cell, and various supporting cells. The lens of each ommatidium focuses light onto the retinula cells, which detect the photons and convert them into electrical signals to be processed by the organism's nervous system. This unique structure allows arthropods to have a mosaic compound eye, which provides a wide field of vision and allows for the detection of movement, but with a limited resolution.
The arrangement and number of ommatidia in an ommateum can vary depending on the species. Some arthropods may have thousands of ommatidia, resulting in a highly developed visual system. The ommateum is typically located on the head of the arthropod, helping it to navigate its environment, detect prey or predators, and respond to changes in light intensity.
In summary, an ommateum is an eye structure found in arthropods, consisting of numerous ommatidia that work together to provide visual perception and contribute to the organism's overall visual system.
The word "Ommateum" is derived from the Greek word "ommatēion" (ὀμματήιον), which means "little eye" or "eyeball". It is a combination of the Greek words "omma" (ὄμμα), meaning "eye", and the suffix "-eion" (-ήιον), denoting a diminutive form. In scientific contexts, the term "ommateum" refers to the compound eye found in insects and crustaceans.