An Updated Classification of the Recent Crustacea

fication (see also Negrea et al., 1999). Therefore,
with trepidation and against our own recommendations
(Martin and Christiansen, 1995a), we have
resurrected the name Phyllopoda, using it this time
to include the extant Notostraca and the bivalved
branchiopod groups (i.e., all branchiopods except
the Anostraca). We have credited the taxon name
to Preuss (1951), who was, to our knowledge, the
first person to use the name Phyllopoda in the sense
that we are using it (to contain all branchiopods
other than the anostracans). This decision will surely
prompt arguments from many current students
of the Branchiopoda (see especially Fryer, 1987c,
1995, 1999b).
There have been many significant findings in extant
and extinct branchiopods that have altered our
view of branchiopod relationships since the Bowman
and Abele (1982) classification. Morphological
treatments have included Fryer (1983, 1985,
1987a–c, 1995, 1996a, b, 1999), Martin (1992),
Martin and Cash-Clark (1995), Walossek (1993,
1995), Olesen et al. (1997), Olesen (1996, 1998,
1999), Thiéry (1996), Amoros (1996), and Negrea
et al. (1999), to mention only a few of the recent
papers. There have also been several attempts to
deduce branchiopod relationships using molecular
data, including Hanner and Fugate (1997) and
Spears and Abele (1997, 1998, 1999b, 2000). In
the current classification, we have attempted to reconcile
some of the recent morphological and molecular
findings, but earlier classifications should
not be discarded as being out of date or invalid.
Indeed, many of the most detailed accounts of
branchiopods remain the older, classical treatments,
and to ignore these is a grave mistake. Thiéry
(1996, based in large part on Martin, 1992) reviewed
the biology of the noncladoceran groups
(including Cyclestheria among the conchostracans),
and Amoros (1996) reviewed the four ‘‘former cladoceran’’
orders Ctenopoda, Anomopoda, Onychopoda,
and Haplopoda.
SUBCLASS SARSOSTRACA, ORDER
ANOSTRACA
Within the Anostraca, Brtek (1995) elevated the
former chirocephalid subfamily Artemiopsinae to
family level and thus recognized the Artemiopsidae.
Earlier, Brtek (1964) established the family Linderiellidae.
However, Denton Belk (pers. comm.) believed
these moves are unwarranted. Concerning
the Artemiopsidae, Belk stated, ‘‘placing this single
genus in a separate family obscures the many features
it shares with other genera in the Chirocephalidae,
and is thus a hindrance to having a meaningful
taxonomic classification of the Anostraca.’’
Concerning the Linderiellidae, he noted that ‘‘these
genera have antennal appendages and some penal
features that suggest they are related to other genera
of the Chirocephalidae; separate familial status
obscures these seemingly significant similarities.’’ In
light of Belk’s expertise with anostracans, we have
followed his suggestion and have not recognized
these two families, although they are recognized in
the latest key to families and genera (Brtek and
Mura, 2000). Our classification of the Anostraca
therefore follows Belk (1996), with the exception
of the Linderiellidae (which was included by Belk,
1996, but is not included here). A recent molecular
analysis (Remigio and Hebert, 2000) of the relationships
among extant anostracan families suggested
two clades, one containing Artemiidae and
Branchipodidae and the other containing the other
five families.
SUBCLASS PHYLLOPODA
By placing anostracans in a subclass separate from
all other branchiopods, we are assuming also that
the other branchiopods form a monophyletic
grouping. In other words, we believe that the notostracans,
conchostracans, and cladocerans are
more closely related to one another than any of
those groups is to the anostracans. There are some
morphological features (e.g., Negrea et al., 1999)
and molecular data (e.g., Spears and Abele 1997,
1999b, 2000) that suggest this might be true. This
arrangement has been proposed by many other
workers as well (some of whom, such as Walossek,
1993, 1995; Walossek and Müller, 1998, have also
employed the name Phyllopoda in the same sense
that we are using it).
ORDER NOTOSTRACA
It may be necessary, once fossil taxa are included
in this classification, to someday resurrect Tasch’s
(1969) name Calmanostraca to accommodate the
extant notostracans and the extinct and obviously
closely related Kazacharthra. The sole family of extant
Notostraca, Triopsidae, is credited to Keilhack
(‘‘Kielhack’’ was a misspelling in Bowman and
Abele, 1982), and that date has been changed from
1910 to 1909 (L. Holthuis, pers. comm.). Although
the original spelling was Triopidae, as listed in
Bowman and Abele (1982), the spelling Triopsidae
(based on the genus Triops) was entered in the Official
List of Family-Group Names in Zoology by
the ICZN, Opinion 502 (M. Grygier, pers. comm.).
ORDER DIPLOSTRACA
As noted above, the Phyllopoda as used here includes
the orders Notostraca and Diplostraca (a
name that predates Onychura used by some authors,
such as Walossek, 1993, and Negrea et al.,
1999). Whether these are indeed sister taxa is unclear;
there is some morphological and molecular
evidence to suggest that this might not be the case.
Recognition of the taxon Diplostraca indicates our
feeling that the former conchostracan and cladoceran
groups are indeed related. There appears to be
some morphological (e.g., see Walossek, 1993; Olesen,
1998; Negrea et al., 1999) and molecular
(Spears and Abele, 2000) evidence supporting this
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