REVSYS: Rennaissance Taxonomy of Semaeostome Scyphomedusae
A Systematic Framework for Understanding Jellyfish Blooms and Invasive Species

NSF DEB-0717078  


Approximately 63 morphospecies of semaeostome jellyfishes, divided among 19 genera and three families, are currently described world-wide. The low taxonomic diversity purportedly reflects low levels of endemism and a high proportion of cosmopolitan species. However, recent molecular analyses suggest 2-to-10-fold greater species diversity in many genera and changes to long-standing phylogenetic hypotheses, suggesting that there have been major difficulties in inferring the taxonomic significance of historically used morphological features due to a dearth of characters, homoplasy, incorrect assignment of homology, and various other problems.

Recent quantitative statistical analyses of morphology in several semaeostome genera have, however, revealed that macromorphological features may be more numerous than previously thought. Moreover, most morphological features are variable and many molecularly-inferred species may also be morphologically distinguishable using univariate, multivariate and phylogenetic statistics. Such statistical morphological analyses may therefore contribute to integrative phylogenetics and a renaissance in scyphozoan systematics.

We propose to extend the developing quantitative and statistical approach to morphological analyses of scyphomedusae in unison with more rigorous multi-locus molecular phylogenetic analyses. Our goals are [i] to generate a robust approach to species identification and description for semaeostomes employing, at least in part, morphological information and [ii] to make the approach accessible to biologists who need accurate identifications in the field.

Our objectives are: [1] Inventory existing natural history collections of all known species of semaeostomes from diverse geographic locations, including the type localities whenever possible. [2] Use collections to establish methods for collecting data suited to rigorous statistical comparative morphological analyses of medusae. [3] Use existing collections that are suitably preserved to generate a robust phylogeny based on DNA sequencing of 2 mitochondrial and 4 nuclear markers. [4] Integrate morphological and molecular data to [a] identify morphological characters, or suites thereof, that can be used to reliably identify semaeostome species and [b] revise the systematics of species in the three semaeostome families including publishing new species descriptions. [5] Develop tools that use the new systematic framework to improve the accuracy of future systematic research. [6] Make these tools widely available to enable non-specialists to use morphological characters to accurately identify semaeostomes in the field.

Broader impacts: Accurate species descriptions are important to many scientific disciplines. Our project will establish methods that will resolve the currently confused systematics of semaeostomes thus providing a robust evolutionary framework for integrative and comparative studies of ecological variation and tools for reliable identification of species causing jellyfish blooms and of invasive species. We will establish widely accessible, easy to use, web-based protocols for identifying semaeostomes including an interactive polychotomous key. The Scyphozoan website will be further developed as the source for gathering and depositing methods, data, and analyses (e.g. spreadsheets, database, digital images, sequence alignments, phylogeny reconstructions, image analysis) pertinent to semaeostome medusae.

Benefits to society include the provision of information on jellyfish species that is applicable to the management of coastal ecosystems and fisheries, and to the public understanding of the marine environment both domestically and internationally.



PI: Michael N Dawson
co-PI: Allen G. Collins
Postdoc: Keith M. Bayha
Graduate: Liza E. Gomez Daglio








Scyphomedusae in the families Cyaneidae (LEFT - top: Cyanea sp.; bottom: Cyanea annaskala),
Ulmaridae (CENTER - top: Aurelia sp.1; bottom: Tiburonia granrojo), and Pelagiidae (RIGHT - top: Chrysaora sp.; bottom: Pelagia sp.). These three families make up the traditionally recognized Order Semaeostomeae.






Collaborating on the project
How to get involved

Menu:       Overview       Collecting       Sending specimens       Taxonomic scope       Expenses       Publication       Other

The aim of this revisionary systematics (REVSYS) project is to gather large amounts of quantitative morphometric data and DNA sequence data from new and existing specimens to generate a robust systematic revision of the three families of semaeostome scyphomedusae: Cyaneidae, Pelagiidae, and Ulmaridae. This revision will provide the basis for organizing and interpreting distributional, ecological, physiological, and other data data in a rigorous, phylogenetically correct manner. As such, it should promote understanding of which jellyfish bloom, and why, including the contribution of invasive species. Important goals of the project are to foster international collaborations that will promote the global community essential for tackling these major environmental issues.

The following text provides information on the logistics of collaborating on, or contributing to, the project. It is intended as a general guide that should be sufficiently flexible to fit a variety of circumstances. If you have questions or suggestions specific to your circumstances, please write to Mike Dawson Our goal is to foster long-term, fruitful, mutually beneficial research partnerships.


Collecting specimens for the project: (back to menu)

Samples for DNA and morphological analyses are required from each species collected. The following instructions are pertinent to all scyphozoans. Please note that samples for DNA analyses must never be exposed to formalin.

If medusae are large, a small subsample of tissue (one or a few pieces, total ~10-50 cubic mm volume) can be biopsied from the specimen, then placed in a vial with excess (1 ml) 95% ethanol. The remainder of the specimen should then be placed in excess 4% formalin in ambient salinity water (i.e. seawater if it is a marine species, estuary water if it is an estuarine species).

If medusae are small, samples for DNA and morphological analyses can be taken from different individuals if you can be absolutely sure that the different individuals are the same species. Again, samples for DNA analyses should be placed in a vial with excess (1 ml) 95% ethanol; samples for morphological analysis should be placed in excess 4% formalin in ambient salinity water.

Ideally, several medusae of a range of sizes should be sampled for DNA and morphological analyses. If only one large specimen is found, it can be treated as noted above. If only one small specimen is found, it would be best if roughly one quarter of the animal (not including the mouth) is cut away and placed in 95% ethanol, with the rest placed in 4% formalin.

Please individually label each specimen with an unique identifier and include information on collection locality, GPS coordinates if available, date of collection, your name.

A small sample kit with all materials necessary for DNA preservation can be sent to you free of charge.

If possible, please take photographs of the medusae in the water and/or in tanks; photograph the whole medusae, and when possible also the fine structure of the bell, tentacles, and oral arms.


Sending specimens to the US for analyses: (back to menu)

Keep the samples for at least a few weeks after collection to ensure they are well preserved. Please send ethanol-preserved samples for DNA analyses separate from formalin-preserved samples for morphological analyses.

The small vials of 95% ethanol with tissue for DNA analyses can be wrapped in a couple of plastic bags, sealed, put in a padded envelope or box, and mailed safely.

The specimens in 4% formalin should be placed in small, non-breakable (e.g. plastic bag, or plastic bottle), containers with sufficient space to fit the animal and just enough liquid to stop it getting damaged in transit. Remove all air from the container to minimize damage in transit. Make sure the container is well-sealed, then seal it another 3 times in additional bags. Pack the sample with plenty of cushioning inside a box.

Include a note in the box stating the point of origin and destination of the package, and a statement that it is a sample for scientific purposes. This will help it pass through customs easily if the package is checked by a customs officer.

All samples should be mailed to: Dr. Michael N Dawson, School of Natural Sciences, University of California at Merced, PO Box 2039, Merced, CA 95340, phone: (209) 228-4056, fax: (209) 228-4053


Taxonomic scope: (back to menu)

All species of semaeostome scyphomedusae (and also the derived rhizostomes) plus a small sampling of outgroup taxa including cubomedusae, hydromedusae, and stauromedusae.


Expenses: (back to menu)

This projectwill cover moderate costs associated with sampling and shipping specimens. Reimbursement will require original receipts and institutional information for transfer of funds. For more information on reimbursements, please contact Dr. Michael N Dawson.


Publication: (back to menu)

If you make many substantial collections in particular taxonomic groups, we are keen to discuss additional co-authorships on systematic/phylogenetic papers to which those samples contribute significantly. Please feel welcome to discuss this or other appropriate arrangements with Dr. Michael N Dawson.


Other: (back to menu)

Please ensure that you have all necessary permits for collecting and shipping samples. Please abide by postal regulations (in most cases, mailing very small quantities of ethanol and 4% formalin is OK when packed appropriately). We encourage you to also deposit specimens in 4% formalin with your regional museum. If your collaboration with REVSYS can be used to leverage additional support from your home institution or national funding agencies that will contribute to your own work and to the REVSYS project please contact us for letters of support.


If you have any questions regarding collaboration on the project or about scyphozoan jellyfishes, please do not hesitate to contact Mike Dawson


Prepared by M. N Dawson