ArticleZoological letters2015
Evidence for an amphibian sixth digit.
Article in Zoological letters, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 8 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Who cites it
8 citing papers in PubMed, 29 citations in OpenAlex.
- Evolutionary pathway and genetic mechanisms of fin-to-limb transition in vertebrates.Frontiers in cell and developmental biology · 2026Review
- Embryonic and skeletal development of the albino African clawed frog (Xenopus laevis).Journal of anatomy · 2023Article
- Ttc30a affects tubulin modifications in a model for ciliary chondrodysplasia with polycystic kidney disease.Proceedings of the National Academy of Sciences of the United States of America · 2021Article
- Functional morphology and identity of the thenar pad in the subterranean genus Ctenomys (Rodentia, Caviomorpha).Journal of anatomy · 2019Article
- Flight feather development: its early specialization during embryogenesis.Zoological letters · 2018Article
- The origins, scaling and loss of tetrapod digits.Philosophical transactions of the Royal Society of London. Series B, Biological sciences · 2017Review
- The phantoms of a high-seven - or - why do our thumbs stick out?Frontiers in zoology · 2015Article
- Entomological journals and publishing in Japan.Applied entomology and zoologyArticle
Corrections and comments
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Authors and funding
10 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
introductionDespite the great diversity in digit morphology reflecting the adaptation of tetrapods to their lifestyle, the number of digits in extant tetrapod species is conservatively stabilized at five or less, which is known as the pentadactyl constraint.
resultsWe found that an anuran amphibian species, Xenopus tropicalis (western clawed frog), has a clawed protrusion anteroventral to digit I on the foot. To identify the nature of the anterior-most clawed protrusion, we examined its morphology, tissue composition, development, and gene expression. We demonstrated that the protrusion in the X. tropicalis hindlimb is the sixth digit, as is evident from anatomical features, development, and molecular marker expression.
conclusionIdentification of the sixth digit in the X. tropicalis hindlimb strongly suggests that the prehallux in other Xenopus species with similar morphology and at the same position as the sixth digit is also a vestigial digit. We propose here that the prehallux seen in various species of amphibians generally represents a rudimentary sixth digit.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.