The evolutionary significance of the earliest cloacal opening in Synapsida.

Lorenzo Marchetti, Antoine Logghe, Arnaud Rebillard, Mark J MacDougall, Jörg Fröbisch

Abstract read

In one paragraph

Article in iScience, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it

0cells of the map it votes in

0citing papers in PubMed

–field-weighted citation impact

1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

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.

2 · The registry

The trial behind it

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Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

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0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Lorenzo MarchettiMuseum für Naturkunde Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstraße 43, Berlin 10115, Germany.

Antoine LoggheCentre de Recherche en Paléontologie - Paris, UMR 7207 - CNRS, MNHN, SU, Muséum National d'Histoire Naturelle, 8 rue Buffon, CP38, Paris, France.

Arnaud RebillardMuseum für Naturkunde Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstraße 43, Berlin 10115, Germany.

Mark J MacDougallBrandon University, 270 18th Street, Brandon, MB R7A 6A9, Canada.

Jörg FröbischMuseum für Naturkunde Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstraße 43, Berlin 10115, Germany.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

The cloaca is a fundamental structure of modern terrestrial vertebrates, including the terminal parts of the urogenital and digestive systems that converge in a single channel and opening (vent). Although it is widespread in amphibians and reptiles (including birds) and occurs in mammals, the fossil record of this structure is scarce. Here we present an exceptional specimen from the early Permian Bromacker locality (294 Ma), which includes a tail impression with two rows of elevated scales separated by a vertical slit, that we interpret as cloacal lips and vent. Because of its morphology and association with the footprint

Indexed as

Bromackercloacaearly Permianevolutionresting tracesynapsidsterrestrialtrace fossilsvent

Identifiers

PMID42472119

DOI10.1016/j.isci.2026.116752

PMCPMC13380424

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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.