Key to Order Semaeostomeae

Phylum Cnidaria
 Class Scyphozoa

General characteristics of Order Semaestomae:  Mostly moderate to large in size.  Corners of mouth drawn out into four gelatinous, frilly lobes (oral arms).  Margine of bell usually has lappets but is not deeply scalloped into pedaliaTentacles on margin of bell contain extensions of the radial canals.  Stomach has gastric filaments.

Key taken primarily from  Kozloff, 1987, 1996 p. 65.  (Copyright 1987, 1996, University of Washington Press.  Used in this web page by permission of University of Washington Press)
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1a Tentacles short, forming a fringe at the marigin of the bell; with 8 marginal lobes; with 8 rhopalia, these with a small tentaclelike lappet on both sides 2
1b Tentacles long, arising singly from the clefts between lappets, or in groups of several to many from the underside of the bell; with 8 or 16 rhopalia, these without tentaclelike lappets 3
2a Subumbrellar canals directed toward the rhopalia not branched except proximally, and the canals midway between them not branched at all; margin not brown; gonads usually reddish, purple or bluish (called Aurelia aurita in Kozloff's keys, now changed to A. labiata) Aurelia labiata
2b Subumbrellar canals profusely branched, with numerous lateral diverticula that anastomose; margin dark brown Aurelia limbata
3a Tentacles arising from the underside of the bell 4
3b Tentacles (usually 24) arising from the clefts between the lappets at the margin of the bell 5
4a With 16 nearly equal marginal lobes, these arranged in 8 pairs, with the 8 rhopalia situated between the pairs; with 8 U-shaped groups of subumbrellar tentacles (each group may have as many as 150 tentacles arranged in up to 4 rows) Cyanea capillata
4b With 16 rounded lobes alternating with smaller lobes that are divided in such a way that they resemble fishtails (the 16 rhopalia are situated on these); with 16 linear groups of subumbrellar tentacles (up to 25 tentacles in each group)
Phacellophora camtschatica
5a Bell amber-colored, darkest near the margin.  An indistinct, pale star pattern radiating to the margin may or may not be present Chrysaora fuscescens
5b Bell light-colored, with a dark pattern consisting of a ring near the apex and 16 evenly-spaced streaks radiating to the margin, each streak being flanked on both sides by a dark crescent Chrysaora melanaster

Taxonomic Levels Represented in this Key:

  Aurelia labiata
  Chrysaora fuscescens
  Cyanea capillata
  Phacellophora camtschatica

Page created by Christina Smith 7-2002
Edited by:  Dave Cowles 2002-2010
Edited by Hans Helmstetler 12-2002