An Updated Classification of the Recent Crustacea

the former thaumastochelids being treated as Nephropidae),
as there was also strong support in
their analysis for grouping at least some thaumastochelid
genera together (Tshudy and Babcock,
1997: fig. 1).
Superfamilies Astacoidea and Parastacoidea
Monophyly of the freshwater crayfishes now appears
secure based on adult morphology, sperm ultrastructure,
embryology, and molecular data (e.g.,
see Crandall, 1999; Crandall et al., 2000; Scholtz,
1998, 1999). Scholtz (1998, 1999) reviews evolution
of the crayfishes and confirms that there are
two distinct clades within the group (i.e., within his
Astacida) corresponding to the northern hemisphere
Astacoidea (families Cambaridae and Astacidae,
the latter of which is probably paraphyletic)
and the southern hemisphere Parastacoidea (family
Parastacidae). Crandall et al. (2000), using over
3000 nucleotides from 3 different genes, have confirmed
both the monophyly of the freshwater crayfishes
(Astacoidea Parastacoidea) as well as the
monophyly of the astacoid and parastacoid clades.
Thus, our current classification is misleading in that
these two superfamilies (the Astacoidea and Parastacoidea)
are still treated as being of equal rank
with three other superfamilies in the Astacidea
when in fact they need to be depicted as more closely
related to each other than either is to any other
astacidean superfamily. Scholtz (1999) also proposes
that the crayfishes are not closely related to homarids
(not supported by Crandall et al., 2000) but
are instead members of ‘‘a large group including
Thalassinida, Anomala and Brachyura’’ (see also
Scholtz and Richter, 1995). Taylor et al. (1999)
added some insights into evolution within the
group based on well-preserved fossil material from
China.
INFRAORDER THALASSINIDEA
Monophyly of the thalassinideans is uncertain; at
least some morphological and molecular analyses
indicate that the group is not monophyletic (e.g.,
Tudge, 1995; Morrison and Cunningham, 1999).
The propensity to construct complex vertical burrows
is one character that has been postulated as
defining the group (Atkinson and Taylor, 1988;
Griffis and Suchanek, 1991; Scholtz and Richter,
1995), as has the presence of a dense row of long
setae along the lower margin of the second leg
(Poore, 1994, 1997). We have followed the revision
by Poore (1994:92) (who also established the family
Strahlaxiidae), with the only difference being
that some of the authors and dates of some taxa
have been changed to earlier usages according to
L. Holthuis (pers. comm.). Relationships among the
extant superfamilies, families, and genera were suggested
by Poore (1994). Poore’s resulting classification
(1997:92), like ours, does not adequately
display all of the relationships suggested by his phylogenetic
analysis (Poore, 1994:120). In particular,
the Axioidea is the sister group to the Thalassinoidea
Callianassoidea in his phylogeny, whereas
in his classification, all three are treated as superfamilies.
The family Ctenochelidae is acknowledged
by Poore (1994) to be paraphyletic (although Tudge
et al., 2000, argued for ctenochelid monophyly).
Poore (1997) subsequently addressed three of these
families and their relationships in greater detail
(Callianideidae Kossman, Micheleidae Sakai, and
Thomassiniidae de Saint Laurent).
In the superfamily Callianassoidea, the family
Axianassidae was removed by Poore (1994), and
the family Ctenochelidae was erected by Manning
and Felder (1991). As noted above, Tudge et al.
(2000) supported the monophyly of the family Callianassidae
and the family Ctenochelidae (while
noting that the latter includes, at least in their analysis,
the genus Anacalliax, considered by some
workers to belong to the Callianassidae). In the superfamily
Axioidea, Sakai (1992) first established
the subfamily Micheleinae, elevated to family level
(Micheleidae Sakai) by Poore (1994), and Poore
(1994) erected the Strahlaxiidae. Sakai (1999) recently
has proposed some rather large-scale revisions
within the Callianassidae; his revisions are apparently
at odds with other analyses of the same or
similar taxa (e.g., see Tudge et al., 2000).
INFRAORDER PALINURA
Holthuis (1991) referred to this assemblage as the
Palinuridea, a spelling that would be consistent
with some of our other infraorder names (such as
Stenopodidea, Caridea) but not with others (Anomura,
Brachyura). We have retained the spelling
Palinura. Within the superfamily Palinuroidea, Davie
(1990) felt that synaxids were not deserving of
separate familial status and synonymized the family
Synaxidae with the Palinuridae. However, Holthuis
(1991) continued to recognize them as separate
families, and we have maintained them as separate
families here as well. The family Polychelidae has
been recently reviewed and rediagnosed by Galil
(2000). Removal of the glypheoids from this infraorder
to the Astacidea has been noted above.
INFRAORDER ANOMURA
Our classification follows McLaughlin’s (1983b)
fairly closely, with the exception of the use of the
family name Pylochelidae replacing Pomatochelidae
(following Forest, 1987). McLaughlin (1983a,
b) employed the name Anomala De Haan (as had
Burkenroad, 1981) rather than Anomura H. Milne
Edwards, which had been used by Bowman and
Abele (and many other workers). G. Scholtz (pers.
comm.) also would prefer this usage (Anomala over
Anomura), arguing that when the thalassinoid families
are removed the taxon composition changes
and thus the name Anomala is the more accurate.
Use of Anomala over Anomura was reconsidered
and discussed at length by McLaughlin and Holthuis
(1985), who pointed out that both names
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