Paedomorphosis and heterochrony in the origin and evolution of the class holothuroidea

Smirnov, Alexander

doi:10.1134/s003103011514018x

Cited by 8 publications

(2 citation statements)

References 46 publications

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“…Paedomorphosis, in turn, is a part of broader ontogenetic processes, heterochronies (different timing of character appearance in ontogeny), which are responsible for both reduction and appearance of more complex characters in evolution [46,54,[56][57][58][59][62][63][64][65][66][67][68]. Though heterochronic retardations of character development in the course of general shifts in life cycles evolution are a major factor for both evolutionary reductions and novelties [60,69], not all reductions can be directly considered paedomorphic ones.…”

Section: Criteria For Distinguishing the Paedomorphic State In Metazoansmentioning

confidence: 99%

Multiple paedomorphic lineages of soft-substrate burrowing invertebrates: parallels in the origin of Xenocratena and Xenoturbella

et al. 2020

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Section: Criteria For Distinguishing the Paedomorphic State In Metazoansmentioning

confidence: 99%

Multiple paedomorphic lineages of soft-substrate burrowing invertebrates: parallels in the origin of Xenocratena and Xenoturbella

et al. 2020

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“…Holothuroids with a "testate" skeleton tend to have large imbricating plate ossicles in their body walls. Pawson and Fell (1965) and Haude (1992;1995) suggested that extant holothuroids with isolated ossicles arose from heavily-plated or testaceous holothuroids, while both Kerr and Kim (1999) and Smirnov (2015) suggested that the "test" represents a later innovation. Our results support the latter hypothesis and clearly indicate that the "test" skeletal type arose once or several times (e.g., Haude, 2002) within Dendrochirotida (Fig.…”

Section: Skeletal Elementsmentioning

confidence: 99%

Molecular phylogeny of extant Holothuroidea (Echinodermata)

Miller

Kerr

Paulay

et al. 2017

Molecular Phylogenetics and Evolution

144

115

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Sea cucumbers (Holothuroidea) are a morphologically diverse, ecologically important, and economically valued clade of echinoderms; however, the understanding of the overall systematics of the group remains controversial. Here, we present a phylogeny of extant Holothuroidea assessed with maximum parsimony, maximum likelihood, and Bayesian approaches using approximately 4.3kb of mt- (COI, 16S, 12S) and nDNA (H3, 18S, 28S) sequences from 82 holothuroid terminals representing 23 of the 27 widely-accepted family-ranked taxa. Currently five holothuroid taxa of ordinal rank are accepted. We find that three of the five orders are non-monophyletic, and we revise the taxonomy of the groups accordingly. Apodida is sister to the rest of Holothuroidea, here considered Actinopoda. Within Actinopoda, Elasipodida in part is sister to the remaining Actinopoda. This latter clade, comprising holothuroids with respiratory trees, is now called Pneumonophora. The traditional Aspidochirotida is paraphyletic, with representatives from three orders (Molpadida, Dendrochirotida, and Elasipodida in part) nested within. Therefore, we discontinue the use of Aspidochirotida and instead erect Holothuriida as the sister group to the remaining Pneumonophora, here termed Neoholothuriida. We found four well-supported major clades in Neoholothuriida: Dendrochirotida, Molpadida and two new clades, Synallactida and Persiculida. The mapping of traditionally-used morphological characters in holothuroid systematics onto the phylogeny revealed marked homoplasy in most characters demonstrating that further taxonomic revision of Holothuroidea is required. Two time-tree analyses, one based on calibrations for uncontroversial crown group dates for Eleutherozoa, Echinozoa and Holothuroidea and another using these calibrations plus four more from within Holothuroidea, showed major discrepancies, suggesting that fossils of Holothuroidea may need reassessment in terms of placing these forms with existing crown clades.

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Taxonomy of the Brazilian Apodida (Holothuroidea), with the description of two new genera

Martins

Souto

2020

Marine Biology Research

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Paedomorphosis and heterochrony in the origin and evolution of the class holothuroidea

Cited by 8 publications

References 46 publications

Multiple paedomorphic lineages of soft-substrate burrowing invertebrates: parallels in the origin of Xenocratena and Xenoturbella

Multiple paedomorphic lineages of soft-substrate burrowing invertebrates: parallels in the origin of Xenocratena and Xenoturbella

Molecular phylogeny of extant Holothuroidea (Echinodermata)

Taxonomy of the Brazilian Apodida (Holothuroidea), with the description of two new genera

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