Eualus gaimardii
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Eualus gaimardii is a marine shrimp species of circumpolar, cold waters found in the Atlantic and Pacific.
features
The species reaches a body length of about 80, exceptionally up to 100 millimeters. The body, with the exception of the eyes, is transparent and translucent with a scattered pattern of small red spots, the basic color can vary from whitish to greenish. The belcheri subspecies is also distinguished by a red horizontal stripe pattern on the pleon. Occasional reports of extended red animals are reported. The species shows the typical "shrimp" habitus of the Natantia (Decapoda), with a trunk section covered by the carapace , which is drawn out into a rostrum at the front, large, stalked complex eyes, an elongated, flagellated first antenna and a much shorter, long bristle second antenna, long and thin, rod-shaped legs, an elongated, muscular abdomen (pleon), which ends in a swimming fan and carries a pair of swimming legs ( pleopods ) on each segment .
The species can be distinguished from the representatives of the Crangonidae and Pandalidae occurring in their area of distribution by the small real scissors ( chela ) on the first pair of legs (peraeopods) (subchelated in Crangonidae, no scissors formation in Pandalidae). All other families have exopodites on the peraeopods that the Hippolytidae lack.
Among the Hippolytidae, the species is distinguished by the following characteristics: The carpus of the second peraeopod is divided into seven segments. The rostrum in front of the carapace is long (can reach the length of the carapace) and pointed and serrated on both sides (5–7 dorsal and 3–5 ventral teeth). There are no supraorbital spines above the eye stalks. The third segment of the pleon is mostly drawn out into a lobe-like extension at the top (in the subspecies gaimardii it can be very small or completely absent).
Eualus gaimardii can be confused with Lebbeus polaris and Spirontocaris lilljeborgi .
Occurrence
The distribution area of the subspecies Eualus gaimardii gaimardii is circumpolar in subarctic cold water areas of the East Pacific and Atlantic off Northern Europe south to Denmark and Scotland , in the West Atlantic to Hudson Bay and up to the Saint Lawrence River . Eualus gaimardii gibba is more likely to be found in arctic waters, the southern limit of distribution extends to the northern polar circle , where it can only be found in deeper waters. Both subspecies can also be observed in shallower coastal waters, but also in shallower waters within Norway . Occurrences around Spitzbergen are only certain for Eualus gaimardii gibba , the nominate subspecies has not yet been confirmed with certainty there. The subspecies Eualus gaimardii belcheri is given mainly from the Russian coastal waters. The subspecies of gibba is partially disputed.
Eualus gaimardii can be found on various seabeds, including between algae . It lives in coastal waters and shelf seas up to a depth of about 300 meters.
Others
This shrimp was named after the French surgeon, naturalist, ichthyologist and zoologist Joseph Paul Gaimard (1796-1858).
literature
- VI Sokolov: Suborder Natantia (Order Decapoda). In: BI Sirenko (editor): Illustrated Keys to Free-Living Invertebrates of Eurasian Arctic Seas and Adjacent Deep Waters. Volume 1: Rotifera, Pycnogonida, Cirripedia, Leptostraca, Mysidacea, Hyperiidea, Caprellidea, Euphausiacea, Natantia, Anomura, and Brachyura. Published by Alaska Sea Grant College Program. University of Alaska Fairbanks. Fairbanks, Alaska, USA.
- Lita Greve (1963): The genera Spirontocaris, Lebeus, Eualus, and Thoralus in Norwegian waters (Crust., Dec.). Sarsiah 11: 29-42.
- Marine Species of the St. Lawrence. Identification Guide
- PJ Hayward & JS Ryland: Handbook of the Marine Fauna of North-West Europe. Oxford University Press, 1990.