The DOI matches its Crossref record; 266 of the 270 references it cites were found in a registry or an index.
Animal phylogeny and the ancestry of bilaterians: inferences from morphology and 18S rDNA gene sequences
Abstract
SUMMARY Insight into the origin and early evolution of the animal phyla requires an understanding of how animal groups are related to one another. Thus, we set out to explore animal phylogeny by analyzing with maximum parsimony 138 morphological characters from 40 metazoan groups, and 304 18S rDNA sequences, both separately and together. Both types of data agree that arthropods are not closely related to annelids: the former group with nematodes and other molting animals (Ecdysozoa), and the latter group with molluscs and other taxa with spiral cleavage. Furthermore, neither brachiopods nor chaetognaths group with deuterostomes; brachiopods are allied with the molluscs and annelids (Lophotrochozoa), whereas chaetognaths are allied with the ecdysozoans. The major discordance between the two types of data concerns the rooting of the bilaterians, and the bilaterian sister‐taxon. Morphology suggests that the root is between deuterostomes and protostomes, with ctenophores the bilaterian sister‐group, whereas 18S rDNA suggests that the root is within the Lophotrochozoa with acoel flatworms and gnathostomulids as basal bilaterians, and with cnidarians the bilaterian sister‐group. We suggest that this basal position of acoels and gnathostomulids is artifactal because for 1000 replicate phylogenetic analyses with one random sequence as outgroup, the majority root with an acoel flatworm or gnathostomulid as the basal ingroup lineage. When these problematic taxa are eliminated from the matrix, the combined analysis suggests that the root lies between the deuterostomes and protostomes, and Ctenophora is the bilaterian sister‐group. We suggest that because chaetognaths and lophophorates, taxa traditionally allied with deuterostomes, occupy basal positions within their respective protostomian clades, deuterostomy most likely represents a suite of characters plesiomorphic for bilaterians.
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“The new matrix builds on previously available datasets [2, 11, 13, 53”
From Cambrian Sessile, Suspension Feeding Stem-Group Ctenophores and Evolution of the Comb Jelly Body Plan (2019) · cites this paper as [11]
In the citing paper
“The Bilateria thus derive from a common ancestor, a point repeatedly substantiated in current molecular phylogenies (reviewed in Adoutte et al., 2000;Peterson and Eernisse, 2001).”
From Precambrian Animal Life: Probable Developmental and Adult Cnidarian Forms from Southwest China (2002) · cites this paper as Peterson and Eernisse, 2001
In the citing paper
“Molecular and morphological phylogenies agree that the bilaterian stem group emerged from a common ancestor of bilaterians and cnidarians, which probably existed much deeper in time (Peterson and Eernisse, 2001;Medina et al., 2001;Peterson and Davidson, 2000).”
From Precambrian Animal Life: Probable Developmental and Adult Cnidarian Forms from Southwest China (2002) · cites this paper as Peterson and Eernisse, 2001
In the citing paper
“Molecular and morphological phylogenies agree that the bilaterian stem group emerged from a common ancestor of bilaterians and cnidarians, which probably existed much deeper in time (Peterson and Eernisse, 2001;Medina et al., 2001;Peterson and Davidson, 2000).”
From Precambrian Animal Life: Probable Developmental and Adult Cnidarian Forms from Southwest China (2002) · cites this paper as Peterson and Eernisse, 2001
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Metadata
- Authors
- Peterson, K. J., & Eernisse, D. J.
- Affiliations
- Dartmouth College (US)
- California State University, Fullerton (US)
- Venue
- Evolution & Development
- Publisher
- Wiley
- Published
- 2001-05
- Volume
- 3
- Issue
- 3
- Pages
- 170-205
- ISSN
- 1520-541X (ISSN-L)
- 1525-142X
- OpenAlex
- W2128919173
- Semantic Scholar
- b53cb97dcc586e3a139989e3611350c2c6a26feb
- Cited by
- 529
- References
- 270
- Citations by year
- 2026: 4 · 2025: 10 · 2024: 12 · 2023: 4 · 2022: 6 · 2021: 8 · 2020: 5 · 2019: 5 · 2018: 5 · 2017: 4 · 2016: 10 · 2015: 12 · 2014: 11 · 2013: 15 · 2012: 11
- FWCI
- 41.38
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Evolution & Development (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Life Sciences › Agricultural and Biological Sciences › Animal Science and Zoology › Marine Invertebrate Physiology and Ecology
- Life Sciences › Agricultural and Biological Sciences › Ecology, Evolution, Behavior and Systematics › Invertebrate Taxonomy and Ecology
- Life Sciences › Agricultural and Biological Sciences › Ecology, Evolution, Behavior and Systematics › Protist diversity and phylogeny
- Keywords
- animal phylogeny, bilaterian origin, 18S rDNA, morphological characters, Ecdysozoa, Lophotrochozoa, deuterostomes, protostomes, ctenophores, acoel flatworms, chaetognaths, lophophorates, root placement
- MeSH terms
- Animals, Annelida, Arthropods, Classification, DNA, Ribosomal, Phylogeny, RNA, Ribosomal, 18S, Software, Models, Statistical, Evolution, Molecular
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