Key:  Suborder Flabellifera

Phylum Arthropoda
  Subphylum Crustacea
    Class Malacostraca
      Subclass Eumalacostraca
        Superorder Peracarida
          Order Isopoda
 

Taken primarily from  Kozloff, 1987, 1996 p. 332 (Copyright 1987, 1996, University of Washington Press.  Used in this web page by permission of University of Washington Press)
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Lower taxonomic level Main Page Alphabetic Index Systematic Index Glossary
1a  Pleon with 4 or 5 visible free pleonites, plus the pleotelson 2
1b Pleon with not more than 3 visible or partly free pleonites, plus the pleotelson (pleonite 1 is hidden beneath pereonite 7)(photo) 15
2a Uropod with both rami well developed, these usually lamellar in form (photo); not capable of rolling up into a ball; not boring in wood or kelps 5
2b Uropod with a rudimentary and more or less clawlike exopodite; capable of rolling up into a ball; boring in wood or kelps 3
3a Boring in holdfasts of kelps; incisor process of mandibles with neither a rasplike nor a filelike specialization Limnoria (Phycolimnoria) algarum
3b Boring in wood; incisor process of right mandible with filelike ridges, that of the left mandible with scales that form a rasp 4
4a Dorsal surface of pleotelson without tubercles, but with a slight median ridge that bifurcates posteriorly Limnoria (Limnoria) lignorum
4b Dorsal surface of pleotelson with 3 small tubercles Limnoria (Limnoria) tripunctata
5a None of the pereopods with large, hooklike dactyls for attachment to fishes (but there may be small hooks) (photo) 6
5b Pereopods 1-3, or all pereopods, with large, hooklike dactyls for attachment to fishes 9
6a Posterior border of telson fringed by about 26 short, simple setae; anterior edge of cephalon with an inconspicuous rostrum; on rocky shores, among mussels, etc. Cirolana harfordi
6b Posterior border of telson fringed by long, plumose setae; anterior edge of cephalon with an obvious spatulate rostrum; on sandy shores 7
7a Telson broadly rounded or almost truncate posteriorly Excirolana linguifrons
7b Telson somewhat angular posteriorly 8
8a Tip of angular portion of telson rather sharply pointed Excirolana kincaidi
8b Tip of angular portion of telson rounded Excirolana vancouverensis
9a Pereopods 1-3 prehensile, with hooklike dactyls for attachment to fishes (but some species are free-living part of the time) 10
9b All pereopods  prehensile, with hooklike dactyls for attachment to fishes (photo) 14
10a Flagellum of antenna 1 with numerous articles; propodus of prehensile  pereopods not expanded Aega symmetrica
10b Flagellum of antenna 1 with only 4 to 6 articles; propodus of prehensile  pereopods expanded along the inner margin 11
11a Cephalon drawn out into a spatulate  rostrum, this flanked on both sides by a small projection Rocinela tridens
11b Cephalon drawn out into a more or less triangular rostrum, but the tip of this may be truncated 12
12a Tip of rostrum pointed Rocinela belliceps
12b Tip of rostrum  truncated Rocinela propodialis
13a
13b
14a
14b
15a Not capable of rolling up into a ball; pereopod 1 subchelate in both sexes, pereopod 2 subchelate in the male Tecticeps pugettensis
15b Capable of rolling up into a ball; none of the pereopods subchelate in either sex 16
16a Pleotelson either trilobed or deeply notched at the apex 17
16b Pleotelson neither trilobed nor deeply notched at the apex 20
17a
17b
18a
18b
19a
19b
20a Two or 3 of the visible pleonites (these are free laterally, but not along the midline) reaching the lateral margins; pleopods without respiratory folds 21
20b Only 1 pleonite reaching the lateral margins; pleopods 4 and 5 with respiratory folds 23
21a Three pleonites reaching the lateral margins (photo) 22
21b Two pleonites reaching the lateral margins (the third visible pleonite is "crowded out") (in decidedly brackish or nearly fresh water) Gnorimosphaeroma insulare
22a Basal articles of antennae 1 touching each other in the midline Gnorimosphaeroma noblei
22b Basal articles of antennae 1 distinctly separated from one another by a short rostrum. (common intertidal species; usually under rocks, but also found on floats and pilings and in various other situations) (Gnorimosphaeroma oregonense in key) Gnorimosphaeroma oregonsis
23a
23b
24a
24b
25a
25b



Taxonomic Levels Represented in This Key:

  Excirolana kincaidi
  Gnorimosphaeroma oregonsis
  Limnoria (Limnoria) lignorum
  Rocinela propodialis
 



Page created by Dave Cowles, 2007
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