|Crossota rufobrunnea (Kramp, 1913), top; C. alba Bigelow, 1913, bottom
Phylum Cnidaria / Class Hydrozoa / Order Trachymedusae / Family Rhopalonematidae
If you do any mid-water trawling at depths below 500 meters in many locations in the North Atlantic and North Pacific Oceans, you’re likely to collect a few Crossota rufobrunnea. Although the exumbrella is transparent, the brilliant dark-red subumbrella and manubrium are quite distinctive. A close inspection of the exumbrella reveals a couple hundred fine furrows running from the bell margin to the apex. The 250 or so tentacles are brownish-red in color. This is a small jelly, with bell width to 1.5 cm. The velum is relatively broad. Visible in the photo are the 8 sausage-shaped gonads that are suspended near the apex. They connect to the 8 radial canals. The large manubrium has 4 lips and no peduncle.
A similar species, Crossota alba, is also found in deep-water habitats. It lacks bell pigmentation, and has a black manubrium and 8 white to tan gonads that are attached below the midpoint of the radial canals. Another related species, Vampyrocrossota childressi, is of similar dimensions but is distinguished by its black coloration.
All images in the JelliesZone © David Wrobel and may not be copied or used in any form without permission.