Evidence map›Paper›PMID 33510189›Full record

ArticleScientific reports2021

Extreme miniaturization of a new amniote vertebrate and insights into the evolution of genital size in chameleons.

Frank Glaw, Jörn Köhler, Oliver Hawlitschek, Fanomezana M Ratsoavina, Andolalao Rakotoarison, Mark D Scherz, Miguel Vences

Abstract read
In one paragraph

Article in Scientific reports, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.

0numbers the graph read from it
0cells of the map it votes in
4citing 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

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

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

Who cites it

4 citing papers in PubMed.

  1. Parallel shifts in differential gene expression reveal convergent miniaturization in fishes.Proceedings of the National Academy of Sciences of the United States of America · 2025
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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

7 authors.

Frank GlawZoologische Staatssammlung München (ZSM-SNSB), Münchhausenstr. 21, 81247, München, Germany. glaw@snsb.de.
Jörn KöhlerHessisches Landesmuseum Darmstadt, Friedensplatz 1, 64283, Darmstadt, Germany.
Oliver HawlitschekCentrum für Naturkunde, Universität Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany.
Fanomezana M RatsoavinaMention Zoologie et Biodiversité Animale, Université d'Antananarivo, BP 906, 101, Antananarivo, Madagascar.
Andolalao RakotoarisonMention Zoologie et Biodiversité Animale, Université d'Antananarivo, BP 906, 101, Antananarivo, Madagascar.
Mark D ScherzInstitute of Biochemistry and Biology, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany.
Miguel VencesZoologisches Institut, Technische Universität Braunschweig, Mendelssohnstr. 4, 38106, Braunschweig, Germany.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Evolutionary reduction of adult body size (miniaturization) has profound consequences for organismal biology and is an important subject of evolutionary research. Based on two individuals we describe a new, extremely miniaturized chameleon, which may be the world's smallest reptile species. The male holotype of Brookesia nana sp. nov. has a snout-vent length of 13.5 mm (total length 21.6 mm) and has large, apparently fully developed hemipenes, making it apparently the smallest mature male amniote ever recorded. The female paratype measures 19.2 mm snout-vent length (total length 28.9 mm) and a micro-CT scan revealed developing eggs in the body cavity, likewise indicating sexual maturity. The new chameleon is only known from a degraded montane rainforest in northern Madagascar and might be threatened by extinction. Molecular phylogenetic analyses place it as sister to B. karchei, the largest species in the clade of miniaturized Brookesia species, for which we resurrect Evoluticauda Angel, 1942 as subgenus name. The genetic divergence of B. nana sp. nov. is rather strong (9.9‒14.9% to all other Evoluticauda species in the 16S rRNA gene). A comparative study of genital length in Malagasy chameleons revealed a tendency for the smallest chameleons to have the relatively largest hemipenes, which might be a consequence of a reversed sexual size dimorphism with males substantially smaller than females in the smallest species. The miniaturized males may need larger hemipenes to enable a better mechanical fit with female genitals during copulation. Comprehensive studies of female genitalia are needed to test this hypothesis and to better understand the evolution of genitalia in reptiles.

Indexed as

Biological EvolutionAnimalsBiodiversityFemaleGenitaliaLizardsMadagascarMaleOrgan SizePhylogenyPhylogeography

Identifiers

PMID33510189
PMCPMC7844282

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