| Abstract |
The controversial interrelationships of the major clades of the reptant decapods are resolved
by simultaneous analysis of 16S, 18S, and 28S rRNA sequences in combination with morphology. All major
reptant clades are represented including the first molecular data for the controversial Polychelidae, Glypheidae,
and Enoplometopidae. Interrelationships of major clades in the shortest morphological cladograms were
identical to those based on the molecular partition, and were congruent with those of the optimal combined
analyses. The optimal tree, namely, that exhibiting minimal overall incongruence between morphological
and molecular partitions was achieved under equal transition: transversion weights. Palinura, as traditionally
recognised, is polyphyletic corroborating several recent studies. Infraordinal relationships are robust and
insensitive to transition weight variation. For clades previously comprising the Palinura, we recognise Achelata,
Polychelida and Glypheidea. Polychelida is sister to the remaining Repantia. Achelata is near basal and sister
to Fractosternalia. Contrary to many previous studies, glypheideans are neither basal reptants, nor are they
related to Thalassinidea, Brachyura or Anomura. Glypheidea is sister to Astacidea. A monophyletic Astacidea,
comprising the freshwater crayfish (Astacida) and marine clawed lobsters (Homarida), corroborates most
previous studies. The enigmatic lobster Enoplometopus (Enoplometopoidea) is confirmed as an astacidean
rather than a possible thalassinidean. Unusual characters of the extinct uncinid lobsters, shared with
enoplometopids, suggest close affinity, extending the fossil record of the Enoplometopoidea to the Lower
Jurassic. The Sterropoda concept, comprising (Thalassinidea (Achelata + Meiura)) is not recognised. The
clade formed by Brachyura, Anomura, and Thalassinidea is united by carapace lineae, for which we propose
the new name Lineata. Internal relationships of Anomura recovered in our analyses suggest possible paraphyly
of Galatheoidea and Paguroidea. Relationships within Brachyura indicate podotreme paraphyly, but greater
taxonomic sampling is required to adequately test the status of Podotremata. The anomuran dromiid hypothesis
is unsupported. Seven reptantian infraorders are recognised: Polychelida, Achelata, Glypheidea, Astacidea,
Thalassinidea, Anomura and Brachyura.
KEY WORDS. – Decapoda, Reptantia, phylogeny, molecular, morphology, Lineata new clade. |
