Through phylogenetic analysis based on molecular and morphological characters of selected groups of shrimps in combination with the study of their biogeographical distribution patterns and host-relations, hypothesis on the evolutionary history of these groups are formulated. Special attention is given to marine palaemonid shrimps. These shrimps are living in association with other invertebrates. The co-evolutionary component is studied by means of comparisons between phylogenetic patterns of both shrimps and hosts.
Keywords
Ecological speciation, biogeography, phylogeny, marine biodiversity, Crustacea, Decapoda, Caridea, Palaemonidae, symbiosis, taxonomy, systematics
Researchinterest
A selection of the topics I am working on currently:
- Evolution of symbiotic shrimps
- Descriptions of new species of marine palaemonids
Current TopicCleaning shrimps
Multiple origins and strong phenotypic convergence in fish-cleaning palaemonid shrimp lineages
Several species of palaemonid shrimps are known to act as fish-cleaning symbionts, with cleaning interactions ranging from dedicated (obligate) to facultative. We confirmed five evolutionarily independent origins of fish cleaning symbioses within the family Palaemonidae based on a phylogenetic analysis and the ancestral state reconstruction of 68 species, including 13 fish-cleaners. (Horka et al., 2018)
Keypublications
- Fransen C.H.J.M. 2023. The marine palaemonid shrimps (Crustacea, Deapoda, Caridea) of the Dutch Caribbean. Zootaxa 5387 (1), 1-127. DOI: 10.11646/ZOOTAXA.5387.1.1
- de Gier W., Helleman P., van den Oever J., Fransen C.H.J.M. 2023. Ecomorphological convergence in the walking leg dactyli of two clades of ascidian‐and mollusc‐associated shrimps (Decapoda: Caridea: Palaemonidae). Ecology and Evolution 13 (12), e10768. doi.org/10.1002/ece3.10768
- De Grave S., Decock W., Dekeyzer S., Davie P.J.F., Fransen C.H.J.M., Boyko C.B, Poore G.C.B., Macpherson E., Ahyong S.T., Crandall K.A., Mazancourt V., Osawa M., Chan T.-Y., Ng P.K.L., Lemaitre R., van der Meij S.E.T., Santos S. 2023. Benchmarking global biodiversity of decapod crustaceans (Crustacea: Decapoda). Journal of Crustacean Biology 43, 1–9. doi.org/10.1093/jcbiol/ruad042
- de Gier W., Fransen C.H.J.M. 2023. Polka-dotted treasures: Revising a clade of ascidian- and bivalve-associated shrimps (Caridea: Palaemonidae). Contributions to Zoology 92, 179–282. doi: 10.1163/18759866-bja10042
- de Gier W., Groenhof M., Fransen C.H.J.M. 2022. Coming out of your shell or crawling back in: multiple interphylum host switching events within a clade of bivalve and ascidian-associated shrimps (Caridea: Palaemonidae). Contributions to Zoology 91, 166–198. doi:10.1163/18759866-bja10030.
- Horká I., De Grave S., Fransen C.H.J.M., Petrusek A., Ďuriš Z. 2018. Multiple origins and strong phenotypic convergence in fish-cleaning palaemonid shrimp lineages. Molecular Phylogenetics and Evolution 124: 71-81.
- Horká I., Grave S. de, Fransen C.H.J.M., Petrusek A., Ďuriš Z. 2016. Multiple host switching events shape the evolution of symbiotic palaemonid shrimps (Crustacea: Decapoda). Scientific Reports 6: 26486.
- Grave S. de, Fransen C.H.J.M. 2011. Carideorum catalogus: the recent species of the dendrobranchiate, stenopodidean, procarididean and caridean shrimps (Crustacea: Decapoda). Zoologische Mededelingen 85: 195-589.
PhDsupervision
Naturalis aims to be a breeding ground for international scientific talent. Therefore, PhD's have a special position in our organisation.
Co-promotor:
- Meij, S.E.T. van der. Evolutionary diversification of coral-dwelling gall crabs (Cryptochiridae). Leiden University, defended in 2015.
- Gier, W. de. Ecomorphological aspects in the evolution of symbiotic marine crustaceans. Groningen University, 2019-2024.
- Schoot, R.J. van der. Geassocieerde fauna op koraalriffen: zegen of vloek? Groningen University, 2020-2026.
Teachingactivities
- BSc course Biodiversity II, Leiden University
- MSc course Biological Oceanography, University of Amsterdam
- MSc course Tropical Biodiversity and Field Methods - Marine Edition, Universitas Pattimura, Naturalis Biodiversity Centre and Leiden University
MSc courseMSc course Tropical Biodiversity and Field Methods - Marine Edition, Universitas Pattimura, Naturalis Biodiversity Centre and Leiden University
The course Tropical Biodiversity and Field Methods provides a broad overview of tropical coastal ecosystems and coral reefs, with a focus on Southeast Asia and Indonesia. Students learn about practical aspects of doing field research in tropical coastal ecosystems and coral reefs, including experimental design, data analysis methods, theory of biodiversity data, and the application of biodiversity data in conservation. In addition, students receive basic taxonomic overviews for taxa that are particularly relevant in tropical coastal ecosystems, and practice their identification based on reference collections and own collections to be made during fieldwork. The course also introduces students to molecular methods such as DNA barcoding and metabarcoding for the integrative study of biodiversity. Students learn how to collect and analyze molecular data, and how to integrate these methods with traditional field methods to improve biodiversity research in tropical coastal ecosystems and coral reefs.
The course is held partly in Leiden, partly at a field station on Ambon in Indonesia. The field work consist of (a) demonstrations of field methods and techniques, (b) short research projects carried out by small groups of students.
The course is a unique opportunity to get theoretical as well as practical instructions on tropical coastal ecosystems and coral reefs from a broad range of experienced lecturers, in a setting that allows you to interact informally and intensively with fellow students, including Indonesian ones, as well as more experienced researchers and field biologists. The course is an excellent preparation for fieldwork in tropical coastal ecosystems and coral reefs, as well as for biodiversity research. The course provides study credits and is also a coveted c.v.-item.
Watch trailer Tropical Biodiversity and Field Methods - Marine Edition, Ambon Indonesia, 2025.

In themedia
Artikel door Bart Braun in de rubriek 'De Verdieping' in Trouw - 8 juli 2018: De waanzinnige wasstraat van de poetsgarnaal is van levensbelang
Taxadescribed
Crassimarginatella harmeri Fransen, 1986
Cradoscrupocellaria curacaoensis (Fransen, 1986)
Aspiscellaria carmabi (Fransen, 1986)
Aspiscellaria piscaderaensis (Fransen, 1986)
Aspiscellaria hildae (Fransen, 1986)
Bugula hummelincki Fransen, 1986
Discias pascuensis Fransen, 1987
Palaemonella disalvoi Fransen, 1987
Cuapetes rapanui (Fransen, 1987)
Bitias Fransen, 1990
Bitias stocki Fransen, 1990
Lysmata olavoi Fransen, 1991
Salmoneus sketi Fransen, 1991
Bythocaris akidopleura Fransen, 1993
Jocaste platysoma Fransen, 1994
Chelonika Fransen, 1997
Chelonika macrochela Fransen, 1997
Lebbeus africanus Fransen, 1997
Pontonia manningi Fransen, 2000
Leontoncaris vanderlandi Fransen, 2001
Pontonia pilosa Fransen, 2002
Ascidonia Fransen, 2002
Rostronia Fransen, 2002
Dactylonia Fransen, 2002
Odontonia Fransen, 2002
Odontonia rufopunctata Fransen, 2002
Odontonia seychellensis Fransen, 2002
Bruceonia Fransen, 2002
Poripontonia dux Fransen, 2003
Odontonia maldivensis Fransen, 2006
Periclimenaeus orbitocarinatus Fransen, 2006
Neopontonides brucei Fransen & Almeida, 2009
Pseudopontonides plumosus Snijders & Fransen, 2010
Leontocaris smarensis Cardoso & Fransen, 2012
Nippontonia christellae Fransen, 2013
Hamodactylus macrophthalmus Fransen & Rauch, 2013
Periclimenes macrorhyncha Eilbracht & Fransen, 2015
Hamodactylus paraqabai Horká, Fransen & Ďuriš, 2016
Hamodactylus pseudaqabai Horká, Fransen & Ďuriš, 2016
Paraclimenaeus michaeli Odijk & Fransen, 2017
Pseudocoutierea acutidorsata Olthof, Becking & Fransen, 2018
Odontonia plurellicola de Gier & Fransen, 2018
Halocaridinides socotraensis Fransen & Van Damme, 2018
Hippolyte cedrici Fransen & De Grave, 2019
Hippolyte karenae Fransen & De Grave, 2019
Odontonia kerangcaris Fransen, Groenhof & de Gier, 2021
Polkamenes de Gier & Fransen, 2023
Tympanicheles de Gier & Fransen, 2023
Periclimenes africanus Fransen & Wirtz, 2023

Periclimenaeus cloacola Fransen, 2023
Platypontonia ngae Fransen, 2024