| Abstract |
In the debate over phylogenetic relationships within the Decapoda that has raged for more than a century, the Anomura
has been the source of many “confl icts”, including disagreements over which taxa belong in this morphologically diverse
infraorder, and even what name is appropriate (Anomura or Anomala). The Anomura currently includes 17 families, 222
genera, and about 2,469 species, although 54% of the genera and 43% of the species are paguroids. A number of studies
have summarized the traditional as well as recent concepts of the infraorder that were based on morphology. This review
addresses modern studies on systematics of this group over the last two decades that have been based on molecular as well
as morphological data, and which have continued to add controversy to concepts of anomuran phylogeny. The landmark
study by C.W. Cunningham and co-workers (published in ‘Nature’ in 1992), proclaiming that molecular data confi rmed the
traditional hypothesis on the evolution of king crabs from hermit crabs, was the catalyst for several studies on anomuran
evolution that followed, and is the starting point of this review. Modern studies are divided as follows, and discussed: 1)
morphological, larval and molecular phylogenies exclusively of the Paguroidea and/or Anomura; 2) spermatologically de-
rived phylogenies; 3) information from the fossil record; 4) phylogenetic assessments of anomuran taxa included in general
decapod analyses; and 5) auxiliary information pertaining to the Paguroidea in general, and Pylochelidae in particular. These
studies have made useful contributions to understanding the “big picture” of anomuran relationships but they also have limi-
tations. It is concluded that the Anomura remains today as much a source of discord as it was a century ago, and “confl icts”
in analyses will continue to cloud the landscape until more basic, complete information is gathered for all members of this
intriguing and varied infraorder. |
