Dynamene bidendata

U
ARTHROPODA
Isopoda

Have you ever heard of isopods?

๐Ÿ‘€๐Ÿ–๏ธย Open your eyes, because this species, ๐˜‹๐˜บ๐˜ฏ๐˜ข๐˜ฎ๐˜ฆ๐˜ฏ๐˜ฆ ๐˜ฃ๐˜ช๐˜ฅ๐˜ฆ๐˜ฏ๐˜ฅ๐˜ข๐˜ต๐˜ข, is one of the most commonly found in the intertidal zone on the NE altantic coast! They are typically found on a wide variety of mid- to lower littoral algae, and also in rock pools in the upper littoral zone.

๐Ÿ’š๐Ÿ•ต๏ธโ€โ™€๏ธย I absolutely love the beautiful color pattern of the exoskeleton, perfectly blending with the seaweed, and ideal for camouflage!

๐ŸŒฑ๐ŸŒŠ As you maybe guessed, ๐˜‹๐˜บ๐˜ฏ๐˜ข๐˜ฎ๐˜ฆ๐˜ฏ๐˜ฆ ๐˜ฃ๐˜ช๐˜ฅ๐˜ฆ๐˜ฏ๐˜ฅ๐˜ข๐˜ต๐˜ข is herbivorous, and they eat on the algae that they are found on. Like many animals of the intertidal zone, their life follow the rhythm of tides and they eat only when they are covered by the high tide.

๐Ÿฆ€๐Ÿฆฟ Isopods belong to crustaceans, just like shrimps and crabs, and they also have a hard exoskeleton. There are over 10,000 identified species worldwide, both terrestrial or marine! Their name comes from the fact that they have segments carrying typically 7 similar (โ€œiso-โ€= equal) pairs of legs (-โ€podโ€ = foot).

๐Ÿ˜ˆ๐Ÿชฒ This small isopod of the intertidal zone is 6 to 7mm long, and also called horned isopod. You can easily guess why!

๐Ÿฆท๐Ÿฆทย The name ‘bidentata’ (latin for ‘two-toothedโ€™) comes from the two tooth-like projections on its back, which are unique to males of this species. It makes the pleotelson a key feature for the identification of the sex and the species. In ๐˜‹๐˜บ๐˜ฏ๐˜ข๐˜ฎ๐˜ฆ๐˜ฏ๐˜ฆ ๐˜ฃ๐˜ช๐˜ฅ๐˜ฆ๐˜ฏ๐˜ฅ๐˜ข๐˜ต๐˜ข males, the 6th segment is longer and have this typical pointy shape.

โšง๏ธโšง๏ธ This is a great exemple of ๐˜€๐—ฒ๐˜…๐˜‚๐—ฎ๐—น ๐—ฑ๐—ถ๐—บ๐—ผ๐—ฟ๐—ฝ๐—ต๐—ถ๐˜€๐—บ, that refers to differences in appearance, size, or other characteristics between males and females of the same species. Sexual dimorphism can be observed in many animal species, including mammals, birds, reptiles, fish, and insects.

๐ŸŠโ€โ™‚๏ธ๐ŸฆถUropods are paired appendages found at the rear end (posterior) of crustaceans, such as lobsters, crabs, shrimp, and isopods. Their structure and function can vary widely but they are typically used for locomotion and swimming.

Sources

  • Doris
  • MarLIN
  • Arrontes, J. Diet, food preference and digestive efficiency in intertidal isopods inhabiting macroalgae. Journal of Experimental Marine Biology and Ecology 139, 231โ€“249 (1990).
  • Vieira, P., Queiroga, H., Costa, F. & Holdich, D. Distribution and species identification in the crustacean isopod genus Dynamene Leach, 1814 along the North East Atlantic-Black Sea axis. ZooKeys 635, 1โ€“29 (2016).
  • Wieser, W. Adaptations of two intertidal isopods I. Respiration and feeding in Naesa bidentata (Adams) (Sphaeromatidae). Journal of the Marine Biological Association of the United Kingdom 42, 665โ€“682 (1962).
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