Where can Photeros annecohenae be found?

     Ostracods are found in almost all aquatic environments and occupy a diverse range of niches; however, bioluminescent ostracods (with their luminescent courtship displays) are marine and only found in reef systems in the Caribbean Sea (Torres and Morin 2007). (Other animals found in the Caribbean include green sea turtles and the common jellyfish.) Photeros annecohenae is a grassbed species (Morin and Cohen 2010) and serves the role of a decomposer within its habitat.  Species-specific displays act to isolate a given species, so each particular species of bioluminescent ostracod occupies a certain microhabitat.

     Photeros annecohenae is found in the Caribbean Sea off the coast of Belize. The species can be  extremely abundant in this area, with over 500 individuals found per square meter (Gerrish 2009). As mentioned above, Photeros annecohenae occupies shallow grassbeds (usually of Thalassia testudinalis or Syringodium filiforme (Torres and Morin 2007)), at about four to five meters in depth and typically 12 to 20 meters off the shore. This species of ostracod is primarily benthic, and, therefore, is a “bottom-dweller.” When not displaying, mating or scavenging, Photeros annecohenae resides in the sands or roots of the grassbeds at the sediment-water interphase below where nightly-displays occur. The highest densities of Photeros annecohenae are found in habitats that contain intermediate densities of grass, intermediate depths of four to five meters and in areas of no to low water velocity (See photos at the bottom of the page). Due to their small size, a strong current can easy sweep away Photeros annecohenae, making food acquisition and mating difficult.

      Darkness is also an extremely important part of Photeros annecohenae’s habitat. Bioluminescent displays by males to attract female mates must occur at times within the "dark threshold," so, without darkness these displays would not occur and mating of the species would cease. This would lead to the organism's exclusion from the given habitat. Food acquisition also occurs in times of darkness. Obviously, darkness is a crucial resource for Photeros annecohenae (Gerrish et al. 2009). The organism must reside in an area where complete darkness (the dark threshold) may be reached. Its behaviors fluctuate with differing amounts of light and light intensity (Gerrish et al. 2009). Because of this, the presence of artificial lighting in these habitats may lead to severe consequences for Photeros annecohenae and other dark-dependant organisms (Gerrish et al. 2009).

     Some of the other organisms present in this habitat include other bioluminescent organisms, such as the luminescent syllid polychaete worm and bioluminescent dinoflagellates, as well as sea urchins (of the genus Diadema), manatee grass and turtle grass (in which Photeros annecohenae resides) and the Carnidalfish, Photeros annecohenae's most observed predator.




Curious to learn how Photeros annecohenae has adapted to make life in this environment possible? View the adaptations page.