Evolution of morphology, ontogeny and life cycles within the Crustacea Thecostraca
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Evolution of morphology, ontogeny and life cycles within the Crustacea Thecostraca. / Høeg, Jens Thorvald; Perez-Losada, M; Glenner, H; Kolbasov, GA; Crandall, KA.
In: arthropod systematics & phylogeny, Vol. 67, No. 2, 25.08.2009, p. 199-217.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Evolution of morphology, ontogeny and life cycles within the Crustacea Thecostraca
AU - Høeg, Jens Thorvald
AU - Perez-Losada, M
AU - Glenner, H
AU - Kolbasov, GA
AU - Crandall, KA
N1 - Key words Phylogeny, parasitology, metamorphosis, sessility, larval biology, nauplius, cyprid.
PY - 2009/8/25
Y1 - 2009/8/25
N2 - We use a previously published phylogenetic analysis of the Thecostraca to trace character evolution in the major lineagesof the taxon. The phylogeny was based on both molecular (6,244 sites from 18S rna, 28S rna and H3 genes) and 41 larvalmorphological characters with broad taxon sampling across the Facetotecta (7 spp.), Ascothoracida (5 spp.), and Cirripedia(3 acrothoracican, 25 rhizocephalan and 39 thoracican spp.). Morphological apomorphies are identifi ed in larval morphologyfor almost all major branches within the Thecostraca. Characters from the cypris larva provide a long suite of apomorphiesfor the Cirripedia and reinforce the concept that this larva was a prerequisite to the tremendous success of that taxon.The evolution of parasitism, obligatory in three major taxa, is discussed. We conclude that the last common ancestor tothe Cirripedia was most likely a suspension feeder, and the advanced metamorphosis and endoparasitism known from theRhizocephala and strongly indicated for the Facetotecta are the result of convergent evolution. We also discuss reproductivesystems, which range from separate sexes, over hermaphrodites combined with a separate male sex (androdioecy), to purehermaphroditism. It is concluded, as envisaged by Darwin, that the Thecostraca provide excellent opportunities for studyingthe evolution of a wide range of complex life history traits which can now be better analyzed and understood in a robustphylogenetic framework.
AB - We use a previously published phylogenetic analysis of the Thecostraca to trace character evolution in the major lineagesof the taxon. The phylogeny was based on both molecular (6,244 sites from 18S rna, 28S rna and H3 genes) and 41 larvalmorphological characters with broad taxon sampling across the Facetotecta (7 spp.), Ascothoracida (5 spp.), and Cirripedia(3 acrothoracican, 25 rhizocephalan and 39 thoracican spp.). Morphological apomorphies are identifi ed in larval morphologyfor almost all major branches within the Thecostraca. Characters from the cypris larva provide a long suite of apomorphiesfor the Cirripedia and reinforce the concept that this larva was a prerequisite to the tremendous success of that taxon.The evolution of parasitism, obligatory in three major taxa, is discussed. We conclude that the last common ancestor tothe Cirripedia was most likely a suspension feeder, and the advanced metamorphosis and endoparasitism known from theRhizocephala and strongly indicated for the Facetotecta are the result of convergent evolution. We also discuss reproductivesystems, which range from separate sexes, over hermaphrodites combined with a separate male sex (androdioecy), to purehermaphroditism. It is concluded, as envisaged by Darwin, that the Thecostraca provide excellent opportunities for studyingthe evolution of a wide range of complex life history traits which can now be better analyzed and understood in a robustphylogenetic framework.
M3 - Journal article
VL - 67
SP - 199
EP - 217
JO - Arthropod Systematics & Phylogeny
JF - Arthropod Systematics & Phylogeny
SN - 1863-7221
IS - 2
ER -
ID: 18654141