Jun 30, 2026
2 - SOP for Ctenophora and Cnidaria - Medusozoa
- Melanie Van Weddingen1,
- Bertrand Bed'Hom1,
- Karine Labadie2,
- Janaina Rigonato2,
- Oscar Demonio1,
- Lucas Leclère3,
- Benjamin Girard1
- 1Muséum national d'Histoire naturelle;
- 2Genoscope;
- 3CNRS
- ATLASea
External link: https://www.atlasea.fr/
Protocol Citation: Melanie Van Weddingen, Bertrand Bed'Hom, Karine Labadie, Janaina Rigonato, Oscar Demonio, Lucas Leclère, Benjamin Girard 2026. 2 - SOP for Ctenophora and Cnidaria - Medusozoa. protocols.io https://dx.doi.org/10.17504/protocols.io.261geyq4dv47/v1
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: May 19, 2026
Last Modified: June 30, 2026
Protocol Integer ID: 317454
Keywords: ATLASea, Genome, marine species, Biology, SOP, Medusozoa, Ctenophora, Cnidaria, sop for ctenophora, medusozoa the standard operating procedure, dna extraction, tissue sample, specimen of ctenophora, processing specimen, sop, ctenophora, cnidaria, atlasea program, scope of the atlasea program, medusozoa, standard operating procedure, metadata, collection metadata
Abstract
The Standard Operating Procedures (SOPs) contain general guidance on processing specimen of Ctenophora and Medusozoa (Cnidaria) within the scope of the ATLASea program. The guidance specifically refers to station metadata (or collection metadata), the tissue samples destined for DNA extraction, and to specimen vouchering.
Materials
Lab material :
- Gloves
- Dissection tools (tweezers, scalpels, scissors)
- Petri dish with different size
- Tube rack
- Paper towel
- Ethanol, Bleach, Filtered sea water, Liquid nitrogen
- Wash bottle
- Scale
- Dewar
- Dissection table
- Ice pack
- Tooth brush
Tubes:
- ©CORNING 1.2 ml conical-bottom cryotube, skirted with external thread and natural screw cap [ref Dutscher # 430658]
- ©CORNING 2 ml Cryotube, skirted, external thread with natural screw cap [ref Dutscher # 430659]
- 5 ml screw tube sterile (Eppendorf) [ref Dutscher # 934683]
- 25 ml screw tube sterile (Eppendorf) [ref Dutscher #934685]
- 50 ml Conical Centrifuge Tubes (Greiner) [ref Dutscher #227261]
- 1.5 mL Safe-Lock Tubes (Eppendorf) [ref Dutscher #033290]
Bags:
- Nylon protection net, reusable with drawstring (15x10 cm) [Amazon #https://www.amazon.fr/Anti-Insectes-Protection-Plantes-R%C3%A9utilisables-Anti-Oiseaux/dp/B08XXJMY4C]
- Nylon protection net, reusable with drawstring (15x25 cm) [Amazon #https://www.amazon.fr/AMZMUKAUP-Protection-Raisins-R%C3%A9utilisables-Rangement/dp/B09N7PV2LD/ref=sr_1_1_sspa?crid=2VTI1EVYUW654&keywords=sachet+filet+nylon&qid=1690200116&sprefix=sachet+ny%2Caps%2C213&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1]
- Twist attaches [Amazon #Twist
Attaches Or, 800 Pcs Métallique Pince pour Fermeture Sachet Alimentaire,
Attache Sac pour Paquet de Bonbon, Sachet Plastique, Transparent Cello]
- Zip-Seal Bags (grands sachets) 350x250 mm [ref VWR #129-0307]
- Zip-Seal Bags (petits sachets) 170x120 mm [ref VWR #129-0297]
Scan:
- Bluetooth QR & Barcode to PC application to scan labels with your phone and import the code to
the Excel sheet via Bluetooth: https://play.google.com/store/apps/details?id=dev.fabik.bluetoothhid
- Honeywell Voyager Extreme Performance 1470g-2D [Ref. Fabricant #1470G2D-2USB-1-R]
Photography equipment : see section C of 0 – SOP.
Before start
General recommendations for Ctenophora and Cnidaria - Medusozoa
**Please ensure that you hold sampling permits if these are required, please see the ATLASea Statement
Medusozoa is a subclass in the Cnidaria phylum. There are four classes: Cubozoa, Hydrozoa, Scyphozoa and Staurozoa. Unlike other cnidarians, they are distinguished by having a medusa stage (free-swimming) in their complex life cycle. That stage is characterized by an umbrella-shaped body (bell) with stinging (cnidoblast) tentacles.
Ctenophora is a phylum which contains classes Nuda and Tentaculata. They are typically predators. Unlike medusozoans, with which they share several superficial similarities, they lack stinging cells.
©ATLASea Team photography
Legends : left to right, top to bottom : Diphasia rosacea, Obelia sp., Dynamena pumila, Eudoxoides spiralis, Aglaura hemistoma, Pleurobrachia pileus, Gonionemus vertens, Lampea pancerina, Aurelia coerulea.
Note: some medusozoan species have stinging cells. Species which are known to be dangerous to humans should be avoided unless adequate safety measures are in place. This SOP does not cover precautions against stings and other potential risks.
Sampling
From a boat, use a plankton net to sample small species. Sieve the content of the net after sampling.
For medusae, sample gently with a hand net /tube or zip bag to avoid damage as much as possible.
For polyps, sampling can be performed during diving or by dredging.
For Ctenophora sample gently with a tube or zip bag to avoid damage as much as possible.
Specimens are maintained in ambient seawater containers. At this step, specimens are identified with:
- Sampling date
- Station number allowing to know sampling date, GPS coordinates, sampling method, harvesters, habitat (via a field sheet completed during sampling).
- Tracking sheet with the name of the taxa (specie, genus, … rank), the taxonomist name, the sex ...
Specimen from the dredging and trawling may be in poor condition and must be processed quickly.
Photography
Ideally, images should be taken in the highest quality resolution (macro lens recommended).
In cases where no part of the specimen can be conserved as a voucher, the photographs will serve as a
voucher. These should therefore include relevant identifying features, when possible. This must be discussed with the taxonomist.
Specimen should be photographed in a glass container (not scratched) with sea water.
Water should be clean and changed between each specimen.
The first picture is the reference photo (see 0 – SOP) taken with a ruler, the code identifiers (e.g. ATLASea QR code, MNHN-IK barcode), the tracking sheet and the station label with the specimen.
Take as many detailed pictures of the different parts of the medusae and polyps. For medusae, be sure to take pictures of the bell margin, in addition of pictures of the whole medusae, oral arm, tentacles and of the mouth part. The diagnostic taxonomic characters are at different locations depending on the medusozoan subgroup.
For small individual light microscopy images are recommanded, they can be very helpful for morphological features.
Dissection for Genome Sequencing
1. Due to the gelatinous consistency, size and transparency of the organisms, detailed dissection may be difficult or even impossible. Rinse gently in filtered sea water (FSW) specimens isolated in containers (e.g Petri dish) and if possible, blot out any slime.
For larger specimens :
2. Use any soma/body tissue, gonads, oral arms or tentacles.
3. Avoid any obvious digestive tissue.
Detailed anatomical diagram of a medusae (left ‱Ruiz Villarreal) and a ctenophore (right ‱Kaidor).
4. Dissect at least 15 pieces (approx. 500 mg each). For the firmest specimens, cut each piece into smaller before putting them in separate tubes (with unique identification labels).
5. For small individuals, place the entire specimen in a tube using very fine tweezers with serrated tips, whilst limiting the amount of water placed in the tube. Prepare at least 15 individuals of the same species.
6. Ensure that all tissues from the same individual are correctly identified on the log sheet.
7. Weight the tubes and scan the barcode on the log sheet.
8. Tubes should be flash-frozen in liquid nitrogen.
Voucher sample conservation
Voucher will be stored at MNHN.
It’s better for the morphological preservation of the specimen to fix them in 4% formaldehyde for 1-3 weeks and then to transfer them in 85% ethanol (after 2 water baths).
For polyps: few polyps of the colony used for tissue sampling.
For medusae: For larger specimen, take the leftover after tissue sampling. Preparing a voucher will not be possible for smaller specimens, unless several individuals of the same species are collected at the same time. In this case, take an entire medusa.
Place a barcode MNHN-IK identifier and the station label with the organism in tube/container.
Send to the MNHN.