A classification of living and fossil genera of - Raffles Museum of ...

Chilenophoberidae is arguably monophyletic (Ahyong,
2006; Tshudy & Babcock, 1997), but its relationship to
other higher taxa differs in various studies (Ahyong, 2006;
Rode & Babcock, 2003; Tshudy & Babcock, 1997).
Additionally, some astacid fossil families (e.g.
Protastacidae, Stenochiridae) have been largely or
altogether ignored to date in cladistic analyses. For marine
clawed lobsters, Ahyong & O’Meally (2004) and Ahyong
(2006) are currently the most extensive analyses; both
show good agreement with the results of Tshudy et al.
(2009), who analyzed nephropid phylogeny using 12s and
16s rRNA from most of the extant nephropid genera.
The higher classification presented here is based largely on
Ahyong & O’Meally’s (2004) extensive, combined
morphological-molecular analysis of 45 decapod taxa.
Their analysis shows marine clawed lobsters to be the
sister group to the freshwater crayfish. Within the marine
lobsters, the Enoplometopidae are a sister group to the
Nephropidae + Thaumastochelidae. These results are
corroborated by more recent molecular studies (e.g. Tsang,
Ma et al., 2008). Following Amati et al. (2004), the extinct
Erymoidea is removed to the infraorder Glypheida (see
below).
The thaumastochelids are a morphologically distinctive
and cladistically cohesive monophyletic group, traditionally
recognized as the family Thaumastochelidae.
However, they are depicted as nested within the
Nephropidae in recent molecular analyses (Tsang, Ma et
al., 2008; Tshudy et al., 2009). We follow that arrangement
here.
At a lower taxonomic level (families, genera), Ahyong
(2006) presented the most extensive morphological analysis
of clawed lobster genera to date. His cladogram serves
as the morphological state of the art for comparison to
recent molecular phylogenies (e.g. Tsang, Ma et al., 2008
and Tshudy et al., 2009). Currently, molecular results are in
relatively good agreement with each other but differ significantly
from morphological results (e.g. see Tshudy et
al., 2009).
The freshwater crayfish are a well-established monophyletic
group (Crandall et al., 2000; Scholtz & Richter,
1995). Scholtz & Richter (1995) further suggested that
there are no morphological characters uniting freshwater
crayfishes with the clawed lobsters and that the mud
shrimps (Thalassinidea) might actually be more closely
related to the crayfishes. However, recent analyses support
the sister relationship between clawed lobsters and
freshwater crayfishes (Ahyong & O’Meally, 2004; Bracken
et al., 2009; Breinholt et al., 2009; Crandall et al., 2000;
Dixon et al., 2003; Porter et al., 2005), lending support to
the continued recognition of Astacidea. Within the freshwater
crayfish, there are two monophyletic groups that
correspond to the superfamilies Parastacoidea (the
southern-hemisphere crayfish) and Astacoidea (northern
hemisphere crayfish). The genus level taxonomy has been
De Grave et al.: Living and fossil genera of decapod crustaceans
6
very dynamic of late with three significant alterations, one
by Hansen & Richardson (2006) who sank the genus
Parastacoides Clark, 1936, and created two new genera,
Spinastacoides Hansen & Richardson, 2006, and
Ombrastacoides Hansen & Richardson, 2006. Another
proposal was by Starobogatov (1995), who created six new
genera and 36 new species in the Astacidae. However, his
taxonomy has not been generally accepted by the
community (especially those in Europe where the
Astacidae are found), and therefore we keep to the more
conventional higher taxonomy outlined by Hobbs (1974),
but with the adjustments from Hansen & Richardson
(2006). We should note, however, that this taxonomy
leaves much to be desired, as many of the genera from the
family Cambaridae clearly do not form monophyletic
groups (Breinholt et al., 2009; Crandall & Fitzpatrick,
1996). In addition to these adjustments with the extant
taxa, there have also been recent additions at the family
level (Taylor et al., 1999) and genus level (Martin et al.,
2008) for fossil crayfish. Previous species counts (Crandall
& Buhay, 2008) included the Starobogatov (1995)
taxonomy and species counts as well as counts of
subspecies. The species counts in the present catalogue do
not include subspecies or the Starobogatov taxonomy and
are therefore reduced from the previous counts (but they do
include new species and fossil species published through
31 July 2009).
Glypheida. We follow the results of Dixon et al. (2003),
Ahyong & O’Meally (2004) and Bracken et al. (2009) in
giving infraordinal status to the glypheid lobsters. Further,
as the analysis of Amati et al. (2004) demonstrated that the
erymoids are the sister group to the glypheoids, the
Erymoidea is treated herein as a superfamily within the
Glypheida.
Axiidea and Gebiidea. Our classification of the decapods
formerly treated as the infraorder Thalassinidea follows
recently proposed revisions that have partitioned this
paraphyletic group into two separate infraorders, which
were originally proposed by de Saint Laurent (1979a,
1979b) as “sections,” the Axiidea and Gebiidea, each with
families as reflected in the listings that follow. As reviewed
in the genetically-based revision by Robles et al. (2009),
both morphological observations (Gurney, 1938, 1942; de
Saint Laurent, 1979a; de Saint Laurent, 1979b; Sakai,
2004; Sakai & Sawada, 2005) and previous genetic studies
(Tsang, Lin et al., 2008; Tsang, Ma et al., 2008) lend
support to this arrangement. No genetic support can be
found for retention of the former superfamilies Axioidea,
Thalassinoidea and Callianassoidea as previously applied
by Poore (1994) and Martin & Davis (2001). Within the
Axiidea, the Thomassiniidae and the Callianideidae do not
appear to represent distinct families, and the formerly
separated Eiconaxiidae and Calocarididae appear to be
imbedded within the family Axiidae, no longer warranting
separate family rank (Robles et al., 2009). However, for
now, these four families continue to be included in our list.
It should also be noted that many lower level taxonomic