Not all scyphozoa live the mobile free-swimming existence.  An attractive group known as stauromedusae have forsaken the medusa stage and live their entire lives associated with the benthos.  Their planula larvae are crawlers rather than swimmers.  After selecting an appropriate spot, the planula attaches and eventually develops into a polyp-like form.  Rather than strobilating like other scyphozoan polyps, it develops directly into the stalked adult.  Like coronate medusae, these scyphozoans retain vertical internal septa as adults.  Substrates such as seaweeds and rock serve as sites for attachment.  Swimming is never an option for these lovers of the laid-back sedentary lifestyle.  Small crustaceans are the favored prey, captured by 8 clusters of knobby tentacles.  The wider portion of the body attached to the stem is known as the calyx.  Many stauromedusae have cryptic colors and patterns and are difficult to find in their natural habitats.  They can also present a challenge for identification.  The photographs show the typical stauromedusan body form.  

    Manania handi (top photo) has a calyx shaped like a goblet and may be up to 4 cm total length.  Eight paired arms, each with 15 to 25 tentacles, alternate with 8 small tentacles.  Keeping with this pattern, there are 8 paired gonads.  Calyx color may be green or red, with 4 light-colored interradial strips.  It feeds on amphipods and benthic copepods.  This species grows on eelgrass and seaweeds in quiet subtidal habitats, and is found in the southern Vancouver Island to Puget Sound region.  Manania gwilliami (bottom photo) is another West Coast species, preferring exposed habitats.  It typically has a dark red color with distinct white subumbrellar nematocyst vesicles.  When attached to coralline algae, the cryptic coloration makes it quite difficult to find.  

    Haliclystus spp. (not pictured) includes another group of stauromedusae.  They have a funnel-shaped calyx, which may by up to 3 cm wide, and a stalk nearly the same length as the calyx.  Each of the 8 calyx arms has 30 to 100 knobby tentacles that are arranged like a "pom-pom".  Along the length of each arm is a gonad.  Color may vary from green, brown, yellow, orange, pink, red or purple.  Often cryptically colored and potentially fairly abundant, they inhabit a wide variety of subtidal and intertidal habitats.  Small crustaceans that associate with benthic habitats are the preferred prey.  Various Haliclystus inhabit areas in the North and South Atlantic, and North Pacific (California to Alaska; northern Japan and Russia).  

All photographs © David Wrobel and may not be used or copied without permission!

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