Key:  Family Pinnotheridae

Phylum Arthropoda
 Subphylum Crustacea
  Class Malacostraca
   Subclass Eumalacostraca
    Superorder Eucarida
     Order Decapoda
      Suborder Pleocyemata
       Infraorder Brachyura
        Section Brachyrhyncha

Taken primarily from  Kozloff, 1987, 1996 pp. 416-417 (Copyright 1987, 1996, University of Washington Press.  Used in this web page by permission of University of Washington Press)

An alternate, up-to-date key to many of these species can be found on page 368 of Wicksten, 2009.
 
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Lower taxonomic level Main Page Alphabetic Index Systematic Index Glossary
1a  Width of carapace less than 1.5 times the length 2
1b Width of carapace at least 1.5 times the length 6
2a Carapace calcified and rather firm 3
2b Carapace soft 4
3a Hairs on legs 3 and 4 featherlike and much longer than those on the other legs; dactyls of walking legs decidedly curved; generally living in the mantle cavity of bivalve molluscs (Modiolus modiolus, Mytilus californianus, M. edulis (M. trossulus), Tresus capax, Mya arenaria, Astarte compacta, Cyclocardia ventricosa, Crenella decussata, Kellia suborbicularis), but sometimes free-living mature males and females
of Fabia subquadrata
3b Hairs on legs 3 and 4 not noticeably longer than those on the other legs; dactyls of walking legs only slightly curved; living in burrows of Callianassa (Neotrypaea) and Upogebia Scleroplax granulata
4a Dorsal surface of the carapace with a longitudinal groove extending posteriorly from the orbit of each eye; dactyls of walking legs decidedly curved (in the mantle cavity of various bivalve molluscs; see choice 3a) subadults and ovigerous
females of Fabia subquadrata
4b Dorsal surface of the carapace without a longitudinal groove extending posteriorly from the orbit of each eye; dactyls of walking legs nearly straight 5
5a
5b
6a Corneous tips of dactyls of legs 2-5 decidedly curved 7
6b Corneous tips of dactyls of legs 2-5 nearly straight 8
7a Outer margin of eye orbits (in anterior view) rounded; male with a gap between the dactyl and fixed finger of the chela, but female without this gap (mature individuals, including gravid females, in the bivalve Tresus capax; immature individuals in many bivalves, and sometimes in hosts other than bivalves) Pinnixa faba
7b Outer margin of eye orbits (in anterior view) somewhat acute; both sexes with a gape between the dactyl and fixed finger of the chela (mature individuals in the bivalve Tresus capax; immature individuals in many bivalves, and sometimes in hosts other than bivalves)
8a Propodus of legs 3-5 longer than the dactyl (it is also about 3 times as wide as the dactyl) (in tubes of terebellid polychaetes, including Eupolymnia heterobranchia) Pinnixa tubicola
8b Propodus of legs 3-5 not longer than the dactyl (and not usually more than twice as wide as the dactyl, except in Pinnixa schmitti) 9
9a Inner margin of dactyl of chela with a distinct tooth; carapace about twice as wide as long, rounded laterally (in tubes of the lugworm genus Abarenicola) Pinnixa eburna
9b Inner margin of dactyl of chela without a distinct tooth; carapace more than twice as wide as long, pointed laterally 10
10a
10b



Taxonomic Levels Represented in This Key:

  Fabia subquadrata
  Pinnixa eburna
  Pinnixa faba
  Pinnixa tubicola
  Scleroplax granulata



Page created by Dave Cowles, 2005
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