Evidence map›Paper›PMID 42610324›Full record

ArticleJournal of morphology2026

On Shell Closure and Beyond: Classification and Functional Interpretation of Chela Types in Paguroidea (Decapoda).

Yannic C Ege, Christian Foth, Stefan Richter

Abstract read
In one paragraph

Article in Journal of morphology, 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

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

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

3 authors.

Yannic C EgeAllgemeine & Spezielle Zoologie, Institut für Biowissenschaften, Universität Rostock, Rostock, Germany.ORCID https://orcid.org/0000-0002-9097-1577
Christian FothMuseum für Naturkunde, Leibniz-Institut für Evolutions-und Biodiversitätsforschung, Berlin, Germany.ORCID https://orcid.org/0000-0002-9410-4569
Stefan RichterAllgemeine & Spezielle Zoologie, Institut für Biowissenschaften, Universität Rostock, Rostock, Germany.ORCID https://orcid.org/0000-0002-2865-2751

Funding

Deutsche Forschungsgemeinschaft DFG INST 264/130-1 FUGGDeutsche Forschungsgemeinschaft DFG RI 837/24-1Heisenberg-Programm 562995972
6 · The paper itself

Abstract

In Paguroidea, the chelae of the first thoracopods (chelipeds) encompass heterochelate (unequal), homoiochelate (subequal, weakly differentiated), and homochelate (equal, mirrored) conditions, reflecting functional differentiation and evolutionary adaptation across taxa. For 30 species from seven hermit crab families detailed 3D models of chelae were generated using microCT imaging. For these, 3D shape analysis identified six distinct shape types (I-compact, II- sturdy, III-elongate, IV-scutiform, V-discoid, VI-semidiscoid) across the investigated taxa. These shape types correspond closely with key biological roles. Paired semidiscoid chelae enable symmetrical shelter closure, while scutiform and discoid chelae function in one-sided shelter closure and defense and are associated with the utilization of gastropod shells. Compact and elongate chelae serve in food manipulation and grooming. Sturdy chelae, which include most homoiochelate forms, are associated with intermediate conditions related to alternative defensive strategies, such as complete (deep) withdrawal into shells, preference for shells with narrow apertures, or symbiotic relationships with anthozoans. Phylogenetic patterns might indicate that potentially basal taxa like Pylochelidae retain plesiomorphic, symmetrical semidiscoid chelae, but it cannot be excluded that these homochelate chelae represent an apomorphic condition for the taxon. In any case, the asymmetric hermit crabs (Parapaguridae, Paguridae, Diogenidae, Coenobitidae, Lithodidae) evolved pronounced heterochely, with the dominant chela adapted (primarily) for shelter closure and the subdominant one for feeding and grooming. Homoiochelate forms occur repeatedly across Diogenidae, suggesting multiple evolutionary transitions related to shifts in defensive strategy. The association between chela shape, biological role, and phylogeny highlights the dynamic interplay of evolutionary history, functional demands, and ecological adaptation in shaping hermit crab morphology.

Indexed as

Animal ShellsAnomuraDecapodaAnimalsBiological EvolutionImaging, Three-DimensionalPhylogenyX-Ray Microtomography3D imagingchela shapeevolutionary adaptationfunctional morphologygeometric morphometricshermit crabsPaguroideashell closure

Identifiers

PMID42610324
PMCPMC13482688

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

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.