An Updated Classification of the Recent Crustacea

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Thus, he did recognize (temporarily, at various times) Talitroidea Bulycheva, 1957, Corophioidea Barnard, 1973, and Haustorioidea Barnard and Drummond, 1982. Several of Jerry’s informal ‘‘anglicized’’ groupings of freshwater families (e.g., ‘‘gammarida,’’ ‘‘crangonyctoids,’’ ‘‘hadzioid group,’’ etc., in Barnard and Barnard, 1983; Williams and Barnard, 1988) rather closely resemble some of the superfamilies (and families) formally named and fully defined previously (1973, 1977, 1979, 1982) by Bousfield and co-workers (e.g., about 75% compatibility with Gammaroidea, Hadzioidea, Crangonyctoidea, Melphidippoidea, etc.). However, he did not attempt formal phyletic groupings of most marine gammaridean families, nor formal integration with other amphipod suborders. Unlike Sars (1895), Stebbing (1906), and other ‘‘turn-of-the-century’’ workers, Jerry apparently did not recognize the significance of reproductive form and behaviour in amphipod phylogeny. Jerry’s final major work (with Gordan Karaman, 1991, p. 7) disavowed the significance or use of the formal superfamily concept, and listed families alphabetically rather than phyletically or semi-phyletically (as in Sars and Stebbing, above). Some classifications are based on carefully defined characters and character states that have required (and will continue to require) modification according to features found in subsequently discovered species and genera, and are consistent at proper classificatory levels. The cladistic arrangement by Kim and Kim (1993), reviewed rather unfavourably by Schram (1994), underscores the unreliability of cladistic analysis when care is not taken in the appropriate selection and accurate definition of characters and character states. [Concerning your statement about Bousfield and Shih], Bousfield and Shih (1994) represents an updating and refinement of previous 20 years of study and publication on gammaridean phylogeny. [Concerning your statement about Reptantia], ‘‘Natantia’’ and ‘‘Reptantia’’ are terms (names) pragmatically defined, but not incorporated formally by Bousfield and Shih (1994). The terms are analogous to former groupings of families and superfamilies, etc., within the Order Decapoda. [Concerning your statement about names and dates], omission of author names and dates in tabular listing of families and superfamilies is modeled after similar ‘‘heading’’ omissions in Barnard’s ‘‘Families and Genera . . .‘‘ (1969) and earlier ‘‘Index . . .’’ (1958). Obviously, these names are fully treated in the major references (e.g., Stebbing, 1906; Gurjanova, 1951; Bousfield 1979, 1982, l983; Schram, 1986). Readers are expected to provide something of substance to the discussion, such as commentary on the paper’s extensive analysis of ‘‘across-the-phyletic-board’’ variability of major characters and character states (antennae to telson) that would be of prime significance in a cladistic treatment. [Concerning your statement to the effect that we presented different phylogenetic hypotheses in our 1994 paper], Bousfield and Shih acknowledge (problems in resolution) that they do not have a ‘‘final answer’’ to the probably correct evolutionary history of the Amphipoda (only one answer can be correct!). Their ‘‘semi-phyletic’’ methodology modifies the strictly phenetic format of Sneath and Sokal (1973) by careful ordering of character states to arrive at a ‘‘plesio-apo-morphic index’’ of probably correct phyletic relativity for each taxon. This approach tends to minimize the negative effects of homoplasious convergence in many of these character states (analyzed above). Mike Ghiselin (1984) correctly points out, rigid and uncritical application of cladistic methodology alone quite frequently leads the user to a less-than-credible phylogenetic result. Thus, use of the ‘‘Wagner 78’’ cladistic program often provides multiple ‘‘trees’’ from the same data base, each one different, each one tending to invalidate the other, and none probably correct! [Concerning your statement about cladistic analyses having high priority], to my knowledge, cladistic ‘‘purists’’ have not yet actually demonstrated a cladistically derived treatment of all 118 gammaridean families of your list. Chances of doing so would appear ‘‘slim-to-non-existent.’’ Instead, advocacy of rDNA methodology would probably result much sooner in a most-probably-correct answer! [Concerning your statement that most workers would prefer to see the families listed alphabetically rather than by superfamily], how surprising that such an unsupported statement should come from Les Watling, a confirmed crustacean phylogenist! On more serious reflection, Les may find that quite a few current workers (e.g., Mike Thurston, John Holsinger) do not ‘‘give up’’ so easily on the full solution of this difficult problem. [Concerning your use of the word hypotheses], do you mean ‘‘concepts’’? All family and superfamily names represent ‘‘concepts’’ of presumed natural groupings of species. Some are better defined (in terms of careful definition of character states) and longer time-tested than others. Most superfamily names in Bousfield and Shih (1994) have been carefully and fully (multiple-character) defined, their component families named, and time-tested (by other workers as well) over a 15 year period. Since superfamily taxonomic stability (75%) would appear at least equal to that of the component family-level names of the current Martin–Davis list, although both lists are ‘‘conceptual,’’ neither can realistically be termed ‘‘hypothetical.’’ Additional References [Note: Dr. Bousfield did not supply references to all papers mentioned above.] Bousfield, E. L. 1995. A contribution to the natural classification of Lower and Middle Cambrian arthropods: food gathering and feeding mechanisms. Amphipacifica II(1):3–34. 108 Contributions in Science, Number 39 Appendix I: Comments and Opinions
Bousfield, E. L. 1996. A contribution to the reclassification of neotropical freshwater hyalellid amphipods (Crustacea: Gammaridea: Talitroidea). Bull. Mus. civ. St. nat. Verona 20[1993 (1996)]:175–224. Submitted by Ed Bousfield, Ottawa, Canada AMPHIPODA: GAMMARIDEA There would seem to be a second main reason why you might regret not employing a natural (superfamily) classification of the Gammaridea. Not only the Lysianassoidea, Talitroidea and Corophioidea, but about 75% of superfamilies of the Bousfield– Schram phyletic classification (including Jerry Barnard’s anglicized versions) are variously utilized by major workers today—if only because they make pragmatic (workable) sense. Interestingly, and to my knowledge, none of those who apparently condemn the present superfamily categories because they ‘‘have not been derived cladistically’’ has attempted a natural treatment of all 113 families (embracing 5000 species!) of your list, based on cladistics alone. Why?—not only is the task extremely difficult and time-consuming, but the feasibility of obtaining a single, credible, ‘‘all-inclusive’’ answer with that methodology alone is highly improbable, and I think they know it! On the other hand, rDNA studies seem virtually unaffected by homoplasious convergence of morphological character states ‘‘across the board’’ and are quite promising—if only someone would get started! The second, and perhaps more important, essentially scientific reason is that gammarideans, virtually alone among crustacean higher taxa (including the 3 other amphipod suborders!) would remain unclassified phyletically. Such an anomalous situation will be corrected inevitably—hopefully sooner than later—providing the principal reason for phyletic classification in the forthcoming CNAI lists and Pacific amphipod guide. Sars, Stebbing, and other perceptive ‘‘turn-of-the-century’’ amphipodologists might then cease ‘‘rolling over in their graves’’! Submitted by Ed Bousfield, Ottawa, Canada ISOPODA In the near future, we must abandon the use of Linnean categories, because we are currently identifying many more encaptic levels of monophyletic groups than there are hierarchical levels in the Linnean system. The Paranthuridae, for example, are definitely a monophyletic group that contains further subgroups. To erect new families for these subgroups means to give up a categorical rank for the taxon Paranthuridae. The same problem exists for the Epicaridea. New molecular evidence (Ph.D. thesis of H. Dreyer) proves that these parasites of crustaceans are derived from a common ancestor shared with the Cymothoidae (fish parasites). Thus, the suborder Epicaridea is placed within the suborder ‘‘Flabellifera’’ or, more precisely, within the suborder Cymothoidea sensu Wägele (1989), the sister group of the suborder being a taxon classified as a family. Concerning the hypothesis that the Sphaeromatidae, Serolidae, and other groups are derived from a disc-shaped ancestor (the ancestor of the Sphaeromatidea sensu Wägele, 1989), new evidence was discovered with the fossil Schweglerella stroebli (Polz, H. 1998. Archaeopteryx 16:19–28). This animal shows neither the apomorphies of the Serolidae nor of the Sphaeromatidae or other related extant taxa, but shows those characters identified as apomorphies of the suborder Sphaeromatidea (e.g., disc-shaped body, head immersed in first pereonite, dorsal eyes). The subdivision of the Oniscidea into Tylomorpha and Ligiamorpha does not reflect the phylogeny of terrestrial isopods, as shown by Erhard (1996, 1998). Detailed phylogenetic analyses based on morphological characters will be published soon (Ph.D. theses of C. Schmidt and of A. Leistikow). Submitted by J. W. Wägele, Ruhr-Universität Bochum, Germany SYNCARIDA The author of both the Bathynellidae and Bathynellacea is Chappuis, 1915. I have copied the paper by Chappuis (1915) for you. I am a bit surprised that you cite Lopretto and Morrone (1998) who have added nothing new to our understanding of Syncarida. You should quote those who have. Submitted by H. Kurt Schminke, Universität Oldenburg, Germany DECAPODA: CARIDEA I am puzzled to find the family Barbouridae among the superfamily Bresilioidea. Chace (1997) put them among the hippolytids. Christoffersen (1987, 1990) put them in the superfamily Crangonoidea. Who put them among the bresilioideans, and why? This is not stated clearly in your section on the superfamily Bresilioidea on p. 61. [Editor’s note: the family Barbouriidae Christoffersen was mistakenly placed by us in the Bresilioidea; this has since been corrected and they are now listed among the Alpheoidea.] Otherwise, the classification contains the usual fights between lumpers and splitters. I think that Christoffersen’s classification may fall apart in the future because much of it is based on descriptions from the literature and not on examination of actual specimens. Some of the descriptions are inaccurate or do not contain pertinent information needed in classification today. Submitted by Mary K. Wicksten, Texas A&M University Contributions in Science, Number 39 Appendix I: Comments and Opinions 109
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An Updated Classification of the Re
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Cover Illustration: Lepidurus packa
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SCIENTIFIC PUBLICATIONS COMMITTEE N
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ACKNOWLEDGMENTS We sincerely thank
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An Updated Classification of the Re
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did not want to attempt it. We are
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ored to credit the person or person
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and Boxshall (1996, lichomolgoid co
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animal phyla.’’ For the Crustac
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same persons to comment on the resu
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solved (e.g., Regier and Schultz, 1
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ancestral crustacean is of course n
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fication (see also Negrea et al., 1
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Bowman and Abele in not recognizing
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(Müller and Walossek, 1985), the O
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cerning barnacle evolution (Schram
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parasites of early fish-like verteb
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Boxshall and Jaume (2000, see also
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that reduction in body segmentation
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for a rebuttal of Dahl’s criticis
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the Amphipoda are deserving of stat
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er than Mysida Boas or Mysida Dana)
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tained in our classification, altho
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and Dalens (1999) in that we includ
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subfamilies of the Cryptoniscidae,
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Brusca and Brusca, 1990; Mayrat and
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employed recently by Pérez Farfant
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the former thaumastochelids being t
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Cunningham (1999) data, which sugge
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eventually led us to keep dromiids
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that the trichodactylids may repres
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(1996a-c), Rodríguez (1982, 1986,
Page 65 and 66: CONCLUDING REMARKS We have thorough
Page 67 and 68: Order Pygophora Berndt, 1907 Family
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Page 71 and 72: Nucellicolidae Lamb, Boxshall, Mill
Page 73 and 74: Terrestricytheridae Schornikov, 196
Page 75 and 76: Eusiridae Stebbing, 1888 Exoedicero
Page 77 and 78: Parascelidae Bate, 1862 Platyscelid
Page 79 and 80: Superfamily Oniscoidea Latreille, 1
Page 81 and 82: Family Alpheidae Rafinesque, 1815 B
Page 83 and 84: Trichodactylidae Milne Edwards, 185
Page 85 and 86: H.-E. Gruner and L. B. Holthuis, 1-
Page 87 and 88: zil, ed. P. S. Young, 635-644. Rio
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Page 91 and 92: tacés Péracarides. Memoires de l
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Page 97 and 98: among gammaridean families and amph
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Page 101 and 102: tostraca) form Unguja Island (Zanzi
Page 103 and 104: Saint Laurent, M. de. 1979. Vers un
Page 105 and 106: . 1983a. Evolution of Tanaidacea. I
Page 107 and 108: Lysianassoidea. Journal of Natural
Page 109 and 110: Wills, M. A. 1997. A phylogeny of r
Page 111 and 112: what your sentence says. Second, ju
Page 113 and 114: logeny and taxonomy. This focus on
Page 115: Submitted by Roger L. Kaesler, Pale
Page 119 and 120: knowledge on the phylogeny and the
Page 121 and 122: inoidea is difficult, because they
Page 123 and 124: APPENDIX III. OTHER CRUSTACEAN RESO
Page 125 and 126: (The) Stomatopod Newsletter Editors
Page 127 and 128: links to crustacean societies, cons
Page 129 and 130: (The) Lurker’s Guide to Stomatopo
Page 131 and 132: strategies, and phylogeny, especial
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An Updated Classification of the Recent Crustacea

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