An Updated Classification of the Recent Crustacea
An Updated Classification of the Recent Crustacea
An Updated Classification of the Recent Crustacea
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for a rebuttal <strong>of</strong> Dahl’s criticism). Inclusion <strong>of</strong> leptostracans<br />
within <strong>the</strong> Malacostraca has been fur<strong>the</strong>r<br />
supported by molecular evidence (rDNA data<br />
summarized in Spears and Abele, 1997, 1999; see<br />
also Shultz and Regier, 2000, for EF-1� and Pol II<br />
data). Hessler (1984) established <strong>the</strong> family Nebaliopsidae<br />
in recognition <strong>of</strong> <strong>the</strong> great differences setting<br />
<strong>the</strong> genus Nebaliopsis apart from o<strong>the</strong>r leptostracans,<br />
<strong>the</strong>reby doubling <strong>the</strong> number <strong>of</strong> recognized<br />
families <strong>of</strong> <strong>the</strong> extant phyllocarids. However, J.<br />
Olesen (1999b, and pers. comm.) finds that, depending<br />
upon <strong>the</strong> choice <strong>of</strong> outgroups (and characters)<br />
used in cladistic analyses <strong>of</strong> <strong>the</strong> group (based<br />
on descriptions in <strong>the</strong> literature), <strong>the</strong>re is still some<br />
room for doubt as to whe<strong>the</strong>r Nebaliidae is monophyletic<br />
or paraphyletic (with Nebaliopsis nested<br />
within <strong>the</strong> o<strong>the</strong>r nebaliacean genera). Most recently,<br />
Walker-Smith and Poore (2001) have erected a<br />
third family, Paranebaliidae, to contain <strong>the</strong> genera<br />
Paranebalia and Levinebalia (<strong>the</strong> latter <strong>of</strong> which<br />
was described by Walker-Smith, 2000).<br />
Our treatment <strong>of</strong> <strong>the</strong> Phyllocarida follows Hessler<br />
(1984), Martin et al. (1996), Dahl and Wägele<br />
(1996), and our PEET web page for Leptostraca<br />
(URL http://www.nhm.org/�peet/) in recognizing<br />
two extant families (see Rolfe, 1981, for extinct<br />
phyllocarids) plus <strong>the</strong> recently established family<br />
Paranebaliidae following Walker-Smith and Poore<br />
(2001). Most authors in <strong>the</strong> past have credited <strong>the</strong><br />
family Nebaliidae to Baird (1850). However, according<br />
to L. Holthuis (pers. comm.), Samouelle<br />
(1819:100) mentioned ‘‘Fam. VI. Nebaliadae’’ [sic]<br />
in his ‘‘Entomologist’s Useful Compendium,’’ which<br />
<strong>of</strong> course predates Baird’s (1850) work. Thus, we<br />
have attributed <strong>the</strong> family Nebaliidae to Samouelle,<br />
1819.<br />
SUBCLASS HOPLOCARIDA, ORDER<br />
STOMATOPODA<br />
Several workers, today and in <strong>the</strong> past (examples<br />
include Hessler, 1983; Scholtz, 1995; Richter and<br />
Scholtz, in press), have considered <strong>the</strong> hoplocarids<br />
to be members <strong>of</strong> <strong>the</strong> Eumalacostraca, a placement<br />
that has been used <strong>of</strong>ten and in some textbooks as<br />
well (e.g., Brusca and Brusca, 1990). However, we<br />
have retained <strong>the</strong>ir placement as a separate subclass<br />
within <strong>the</strong> Malacostraca pending fur<strong>the</strong>r exploration<br />
<strong>of</strong> this question (see review by Watling et al.,<br />
2000). Our treatment <strong>of</strong> <strong>the</strong> hoplocarids as separate<br />
from <strong>the</strong> o<strong>the</strong>r Eumalacostraca also is consistent<br />
with some (admittedly weak) molecular evidence<br />
(see Spears and Abele, 1997, 1999b) and<br />
with cladistic analyses based mostly on fossil taxa<br />
(e.g., H<strong>of</strong>, 1998a, b; H<strong>of</strong> and Schram, 1999).<br />
Schram (1971, 1986) had argued earlier for separate<br />
status <strong>of</strong> <strong>the</strong> hoplocarids as well. Spears and<br />
Abele (1997) could state only that <strong>the</strong> position <strong>of</strong><br />
<strong>the</strong> ‘‘Hoplocarida relative to <strong>the</strong> Eumalacostraca is<br />
equivocal’’ (low bootstrap value) based on rDNA<br />
sequence data, and thus <strong>the</strong>y were ‘‘unable to determine<br />
whe<strong>the</strong>r hoplocarids represent a separate,<br />
independent malacostracan lineage with taxonomic<br />
rank (subclass) equivalent to that <strong>of</strong> phyllocarids<br />
and eumalacostracans.’’ Their subsequent paper<br />
(Spears and Abele, 1999b) seems (to us) to indicate<br />
somewhat stronger evidence that hoplocarids are<br />
not eumalacostracans, but <strong>the</strong> authors are suitably<br />
cautious in not saying so. Without firm indications<br />
that we should do o<strong>the</strong>rwise, we have maintained<br />
separate status for <strong>the</strong> Hoplocarida and Eumalacostraca.<br />
Although a thorough cladistic analysis <strong>of</strong><br />
fossil and extant crustacean taxa by Schram and<br />
H<strong>of</strong> (1998) resulted in a tree that showed hoplocarids<br />
arising from somewhere within <strong>the</strong> Eumalacostraca,<br />
<strong>the</strong>se authors also noted that forcing <strong>the</strong><br />
hoplocarids into a ‘‘sister group’’ position to <strong>the</strong><br />
Eumalacostraca increased tree length by only 1%.<br />
O<strong>the</strong>r workers (e.g., Watling, 1999a), recognizing<br />
how very derived <strong>the</strong> stomatopods are, place <strong>the</strong>m<br />
in <strong>the</strong> Eumalacostraca as <strong>the</strong> sister taxon to <strong>the</strong> Eucarida.<br />
Most recently, Richter and Scholtz (in press)<br />
suggested that hoplocarids occupy a basal position<br />
within <strong>the</strong> Eumalacostraca. Thus, placement <strong>of</strong> <strong>the</strong><br />
hoplocarids continues to be an unresolved issue,<br />
but we felt that <strong>the</strong> weight <strong>of</strong> <strong>the</strong> evidence placed<br />
<strong>the</strong>m outside, ra<strong>the</strong>r than within, <strong>the</strong> Eumalacostraca.<br />
Scholtz (pers. comm.) additionally suggests<br />
that our crediting <strong>the</strong> name Eumalacostraca to<br />
Grobben is <strong>the</strong>refore incorrect, as Grobben included<br />
<strong>the</strong> hoplocarids among <strong>the</strong> Eumalacostraca (but<br />
see earlier notes on names, dates, and <strong>the</strong> ICZN).<br />
Within <strong>the</strong> Hoplocarida, most <strong>of</strong> our changes are<br />
based on <strong>the</strong> catalog provided by H.-G. Müller<br />
(1994) and on Manning (1995), and our final arrangement<br />
<strong>of</strong> families and superfamilies follows <strong>the</strong><br />
recent cladistic analysis by Ahyong and Harling<br />
(2000). Publications that describe or recognize families<br />
or higher taxa <strong>of</strong> stomatopods subsequent to<br />
Bowman and Abele (1982) include Manning (1995,<br />
Indosquillidae, Parasquillidae, Heterosquillidae),<br />
Manning and Bruce (1984, Erythrosquillidae [for<br />
which <strong>the</strong> superfamily Erythrosquilloidea was later<br />
created by Manning and Camp, 1993]), Manning<br />
and Camp (1993, Tetrasquillidae), Moosa (1991,<br />
Alainosquillidae), and Ahyong and Harling (2000,<br />
superfamilies Eurysquilloidea and Parasquilloidea).<br />
Concerning phylogeny within <strong>the</strong> Hoplocarida,<br />
<strong>the</strong>re is recent evidence from several laboratories<br />
that <strong>the</strong> superfamily Gonodactyloidea as presented<br />
in Bowman and Abele (1982) is not a monophyletic<br />
grouping (H<strong>of</strong>, 1998b; Ahyong, 1997; Barber and<br />
Erdmann, 2000; Ahyong and Harling, 2000; Cappola<br />
and Manning, 1998; Cappola, 1999) and that<br />
within <strong>the</strong> gonodactyloids <strong>the</strong> eurysquillids may be<br />
paraphyletic. These same authors disagree over<br />
whe<strong>the</strong>r <strong>the</strong> Bathysquilloidea are monophyletic<br />
(Cappola and Manning, 1998) or not (Ahyong,<br />
1997). A comparative study <strong>of</strong> eye design in stomatopods<br />
(Harling, 2000) also supports a nonmonophyletic<br />
Gonodactyloidea and questions <strong>the</strong> fivesuperfamily<br />
scheme <strong>of</strong> Müller (1994). The nonmonophyly<br />
<strong>of</strong> <strong>the</strong> Gonodactyloidea necessitates <strong>the</strong><br />
creation <strong>of</strong> additional families and superfamilies to<br />
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