An Updated Classification of the Recent Crustacea

cerning barnacle evolution (Schram and Høeg,
1995) reveals mostly that we still have much to
learn about the relationships of the various groups
of maxillopods.
SUPERORDER ACROTHORACICA
For this group, we have followed the classification
of Newman (1996), where acrothoracicans are divided
among two orders, Pygophora (with two
families) and Apygophora (with a single family).
SUPERORDER RHIZOCEPHALA
Our classification of this group follows Høeg
(1992), Høeg and Rybakov (1992), Høeg and Lützen
(1993, 1996), Huys (1991), and Lützen and
Takahashi (1996). Thus, we treat the Rhizocephala
as an infraclass that contains two orders, Kentrogonida
(with three families) and Akentrogonida
(with six families), although there is concern that
one or both of these orders may be paraphyletic
(see Høeg and Lützen, 1993). Jensen et al. (1994a,
b) supported monophyly of the Akentrogonida on
the basis of details of the lattice organs.
Within the Kentrogonida, concerning the issue of
authorship of the families Peltogastridae and Sacculinidae
(which we had earlier credited to Boschma),
W. Vervoort writes (pers. comm.): ‘‘. . . both
the families Peltogastridae and Sacculinidae must
be ascribed to Lilljeborg, 1860. This has been duly
checked. Boschma lived [from] 1893–1976 and
cannot possibly be the author of these two families.
Holthuis and I consulted Lilljeborg’s 1860 publication,
a copy of which is in our library; there is
not a shadow of a doubt concerning his authorship.’’
The family Sylonidae (Sylidae in Bowman
and Abele) has been subsumed within the Clistosaccidae
Boschma, which is now included in the
Akentrogonida (J. Høeg, pers. comm.).
Within the Akentrogonida, three new families
(Duplorbidae, Mycetomorphidae, and Thompsoniidae)
were described by Høeg and Rybakov (1992)
and one new family (Polysaccidae) was added by
Lützen and Takahashi (1996). The Chthamalophilidae
is recognized as a valid family (also following
Høeg and Rybakov, 1992), and, as noted above,
the Clistosaccidae was transferred into the Akentrogonida
from the Kentrogonida.
SUPERORDER THORACICA
Although few new extant families have been suggested
since 1982, there have been significant rearrangements
of the cirripedes (or attempts to rearrange
them) by workers using morphological and
molecular data. Perhaps the most comprehensive is
the cladistic study by Glenner et al. (1995), who
concluded that many currently recognized groups
appear to be paraphyletic, including the groups that
appear in our classification under the headings ‘‘Lepadomorpha’’
and ‘‘Pedunculata.’’ However, Glenner
et al. (1995) also noted that ‘‘we have far to go
before a new taxonomy can emerge’’ and suggested
the continued use of such commonly used terms as
‘‘lepadomorphs’’ or ‘‘pedunculates’’ as long as
workers understand that these are groupings more
of convenience than of common descent. We are
not in agreement with this philosophy and would
prefer to recognize taxa that reflect common descent,
but in this group, it is apparent that we are
not yet at the point where we know which clades
are valid.
For the most part, we have followed the classification
of the Thoracica given by Newman (1996).
Thus, we are recognizing the order Pedunculata (an
old name that was previously thought to lack validity
but that Newman (1996) feels is a natural
assemblage and thus has resurrected) as containing
four suborders. Some of the names in this order
(e.g., Heteralepadomorpha, Iblomorpha, Scalpellomorpha)
are credited to Newman (1987), although
it is clear that these higher taxon names are
based on older works, which perhaps should be
credited as the taxon author and date if we were
to closely adhere to ICZN article 50.3.1 as extended
to higher taxa. Many of the families now treated
in these four suborders were elevated from subfamily
status by Newman (1987). For example, within
the Scalpellomorpha, only the family Scalpellidae
Pilsbry is also found in the Bowman and Abele
(1982) classification. Within the resurrected order
Sessilia (see Newman, 1987; Buckeridge, 1995), the
brachylepadomorph family Neobrachylepadidae
was described by Newman and Yamaguchi (1995)
and the verrucomorph family Neoverrucidae was
described by Newman (1989, in Newman and Hessler,
1989:268; see also Newman, 1989). Within
the Balanomorpha, Buckeridge (1983) added the
superfamily Chionelasmatoidea, containing the single
family Chionelasmatidae. Suggestions for evolutionary
radiations within the Balanomorpha were
presented by Yamaguchi and Newman (1990). A
recent molecular analysis of several thoracican taxa
(Harris et al., 2000) suggests that the sessile barnacles
are monophyletic but that the pedunculate
forms (our Pedunculata) may not be.
SUBCLASS TANTULOCARIDA
The Tantulocarida, bizarre parasites of other deepsea
crustaceans, were known as early as the beginning
of the 20th century (reviewed by Huys, 1990e,
1991; Boxshall, 1991, 1996) but were recognized
as a distinct class of Crustacea only in 1983
(Boxshall and Lincoln, 1983), just too late for inclusion
by Bowman and Abele (1982). They have
since been relegated to a subclass or infraclass within
the Thecostraca or have been proposed as the
sister group to the Thecostraca within the Maxillopoda
(e.g., Boxshall and Huys, 1989a; Boxshall,
1991; Huys et al., 1993). Our classification follows
that of Huys (1990e) (see also Huys, 1991, where
two families are also described). Discussions of the
relationships of tantulocaridans (all of which lack
Contributions in Science, Number 39 Rationale 23