This file last modified: 01 February 2018

Preservation and handling instructions for vernal pool crustaceans

The Natural History Museum of Los Angeles County (NHM) is the repository of the nation’s second largest collection of crustaceans, second in size only to that of the USNM/Smithsonian Institution. The Museum is committed to the long-term care, curation, and growth of its collection. Our collections contain invaluable resources and are available for scientific study. We are pleased to accept and catalog high quality crustacean wet preserved specimens and dried resting eggs (often called “cysts”).

This document describes specimen preservation and locality information requirements. This information is useful for “large branchiopod” crustaceans (fairy and brine shrimp, tadpole shrimp, and clam shrimp) but applies equally well to all small freshwater crustaceans (e.g. copepods, ostracods, smaller branchiopods [cladocerans], amphipods, etc.). Check our website for updated versions of this document and associated resources The modification date of this document appears at the beginning and end, and a list of changes is at the top.

Our aim is to maximize the scientific value of your collecting efforts and the biological usefulness of specimens for future studies. This document provides a brief overview of (1) techniques and supplies needed for collecting in the field, (2) specimen handling in the laboratory, and (3) preparing specimens for transfer to the NHM. To make sample collecting and processing as simple and efficient as possible, collecting kits can be obtained from NHM (see Collecting Kits).

In the Field

Materials

See kit description for vendors.

• Appropriately-sized mesh for capture of
  • large branchiopods: 3,175 µm mesh net or smaller
  • juvenile/larvae/small crustaceans (e.g. cladocerans): 240 µm mesh net
  • copepods/ostracods: 63 µm mesh net
• 95% ethanol
• 2 plastic whirl-top bags
• Funnel to transfer netted specimens into whirl-top bag
• No. 2 pencil
• Labels

Collect specimens using the appropriately-sized mesh net (refer to materials guide above). The dip net with specimens is then gently rinsed to wash off sediment. If you so choose, you may treat the specimen with carbonated water prior to the next step — this will ensure that the specimen dies in a manner that will facilitate posthumous identification. Place the funnel into the mouth of a whirl top bag. Invert your net containing specimens over the funnel, and wash the specimens into the bag with 95% ethanol in a volume of 3:1 alcohol to specimen(s). Close the whirl top bag and drop it into the second whirl top bag. Use a number 2 pencil to write your unique field number on the label. Add this label to the outer bag and close it. Move on to the next collecting site.

Sieve for crustacea (“Mermaid’s Bra”)

For processing tiny crustacea in the field (and in the lab), a semi-rigid conical sieve made of Nitex® nylon mesh may be useful. You can make one on your own, based on a template and instructions provided here.

In the Lab

Materials

See kit description for vendors.

• Scissors to cut whirl top bag
• Mesh net (same as used in field or another of the same/smaller size)
• Petri dish large enough to hold specimen
• 95% ethanol

In the lab, cut the top off the outer bag, remove the label and set it aside. Having the label in a separate bag keeps the label from getting tangled with the specimens. Cut the top off the inner bag containing the specimens. Carefully pour the specimens into the same sized or smaller sized net as was used in the field. Invert the net over a Petri dish, rinsing the sample with fresh 95% ethanol. Identify the specimens as usual.

Alcohol

Rinsing specimens with freshwater has the advantage of removing debris material that can otherwise adhere to the specimens. If freshwater is not available in the field, using 95% ethanol directly as a preservative is the next best choice. High grade ethanol (not denatured) can be purchased from vendors listed on the page describing collecting kits. Absolute ethanol (100%) is less desirable than 95% ethanol, because it contains dehydrating agents that can impede subsequent molecular reactions. Also, 95% ethanol is less expensive than absolute ethanol.

In the past, we have sometimes received specimens that were preserved in acetone. It seems that researchers unable to obtain pure ethanol have been substituting denatured alcohol, which is cut (mixed) with acetone to make it denatured. Should you be unable to obtain pure ethanol, please substitute commercial alcoholic liquor (e.g. Everclear® 95% or 75.5%, 150-proof rum, or 150-proof vodka). While not ideal, this substitute increases the possibility that the specimens can be used for molecular genetic studies and is preferable to using denatured alcohol.

Regardless of the fixation/preservation method used, please tell us exactly how specimens were handled (see Collection Data below). The usefulness of your specimens is thus vastly increased.

Preparing for the Museum

Materials

See kit description for vendors.

• Glass shell vial(s) to achieve 3:1 alcohol:specimen ratio (you may use multiple vials if necessary — be sure to keep ratio at or above 3:1)
  • 1.0 dram vial for 1–5 average-sized fairy shrimp
  • 4.0 or 8.0 dram vial for more/larger specimens
• 95% ethanol
• 100% cotton pre-soaked in 95% ethanol (do not use foam, rayon, or other synthetic fiber)
• Plastic screw top shipping tube
• Lot label

Place the identified specimens into the appropriately-sized glass shell vial. Completely fill ial with 95% ethanol. Stopper this vial with a 100% cotton plug. Place this cotton stoppered vial into the plastic screw top shipping tube and add the label — keeping the specimen separate from the label keeps the specimen(s) from becoming entangled with the label and consequently broken or damaged. Fill the shipping tube with 95% ethanol.

The label that is enclosed with the specimen(s) must, at minimum, contain the following information (other information is required in electronic format, see Collection Data below):

Collection Data

Each collection must be accompanied by the following information electronically and in hardcopy format. Send the electronic version along before shipping the hard copy and specimens. Furthermore, be sure to contact lab personnel before accessioning is to occur in order to coordinate the drop-off or shipping. The “Specimen or lot identifiers” in these data must match the identifiers on the labels in the specimen vials (see Preparing for the Museum above).

Each lot within the collection must be accompanied by the following information:

All collection and lot information must be supplied electronically with a hardcopy accompanying the shipment. Our Excel data entry spreadsheet can be downloaded from the NHM Vernal Pool website (see Downloads at the top of this page). If you have additional data, feel free to add columns to the spreadsheet for those data and we will do our best to incorporate them into our collection database. Additional digital resources (e.g. photographs, maps, reports, etc.) are also welcome.

Specimen number or lot number should be the first column. Collection date must be in date-format cells (not free-form “General” or “Text” formatted fields). Latitude and longitude can be in the format collected in the field. If data are in decimal degrees, latitude should be in one column, longitude in a separate column. If data are collected in degrees and decimal minutes or another format, each number should be in a separate column (create new columns if needed).

Permit information (name of the agency issuing the collecting permit and the permit number) is legally required for us to accept samples. Permit numbers will be reported back annually to the U.S. Fish and Wildlife Service.

The Museum reserves the right to refuse specimens with inadequate amounts of usable collection data.

Long-term Storage

Archival quality materials (including high quality alcohol, glass vials, permanent ink or pencil on permanent label paper) should always be used. To minimize the amount of time and money involved with specimen handling, specimens should be placed in small glass shell vials. If you are collecting only a few samples, the simplest and least expensive option is to obtain one of our pre-made kits. For large collecting efforts, vendor information is available on the same web page.

Once specimens are received here at the Museum, permanent archival labels will be printed and your vialed specimens will be double-vialed for compact, long-term, easily retrievable storage. Cataloging information can be returned upon request.

Shipping

Materials

See kit description for vendors.

• Previously-prepared plastic screw top shipping tubes containing specimens in vials
• Ziploc or heat-sealed bags
• Bubble wrap, plastic peanuts, or other packing materials

Place the plastic screw top tubes into the Ziploc or heat-sealed bags to prevent leakage. Adequately cushion the lots with the chosen packing material to ensure their safe arrival. Specimens must be sent by registered or certified mail or courier.

Please address packages to:

Natural History Museum of Los Angeles County,
Research and Collections, Crustacea
attention Adam Wall, Collections Manager
900 Exposition Boulevard
Los Angeles, California 90007
Tel. 213 763-3450
email: awall@nhm.org

Note: Donor accepts responsibility for compliance with the current rules and regulations for the shipping of hazardous materials.

Resting Eggs (“Cysts”)

Materials

See kit description for vendors.

• 1 dram screw top glass vial (for use with resting eggs/cysts only)

Identified resting eggs should be placed into 1 dram screw cap glass vials and labeled the same way as the wet preserved specimens. The only difference is that resting eggs stay dry and are shipped dry.

Accessioning

General information

The Natural History Museum of Los Angeles County will accept selected collections of Crustacea for permanent care and curation, including those from vernal pools and other ephemeral freshwater habitats and representatives of threatened or endangered taxa. Note that accessions are not limited to listed or endangered taxa — we will gladly accept specimens of non-endangered species. If properly curated, we will also accept associated fauna captured coincidentally with targeted taxa (i.e. bycatch). The Museum is willing to act as the repository for collections acquired during USFWS or other surveys.

To be accepted for accessioning, the collections must be in adequately preserved condition, meaning that the animals themselves must not have deteriorated and all collecting, preserving, and labeling protocols have been followed (see above). Furthermore, all collections must be accompanied by a detailed list of the specimens being sent as well as copies of any required permits.

The Museum reserves the right to decide whether an incoming collection should be stored topically versus separated and stored according to taxonomic divisions (i.e., storing all members of one family together rather than keeping all collections from one site together).

The Museum further reserves the right to decide which specimens will be maintained for long term storage and which may be passed on to other institutions in exchange or as long term loans for research purposes.

Visit our collection website at https://research.nhm.org/mbc/collections for more information about our holdings and information about our collections. If you have questions about proper handling, please email Adam Wall (awall@nhm.org) or Regina Wetzer (rwetzer@nhm.org) for guidance in preparing your specimens for accessioning into our collections.

Ultimately, our specimens are stored with as much locality/collection information as will fit on a label. Associated data that cannot be included on the label for space reasons are always retained in our electronic database.

Accessioning procedure

1. Contact Adam Wall (awall@nhm.org 213-763-3450) to discuss the particulars of your collection of vouchers to be accessioned.
2. After talking with Adam Wall you must email your completed datasheet as an Excel file and a scanned copy of your signed and completed Deed of Gift for review before you can set an appointment for dropping off vouchers in person to the Museum (our preferred method of delivery) or shipping vouchers to the museum for accessioning.
3. Once your material has been reviewed and approved for accession, an appointment will be made for delivering vouchers to the museum, or permission to ship vouchers will be given.

Accessioning cost

Because of the rising costs of accessioning and maintaining collections, the Natural History Museum reserves the right to charge for accessioning collections on a per-lot basis. This fee varies with the size of the collection, duration of the project, and availability of Museum staff at the time of deposition. The usual per-lot fee is $22 (this fee may be waived at the discretion of the Curator).

If specimen lots are not curated according to the guidelines in the current version of this document, an additional curating fee of $25 per lot will be charged, with a $200 minimum charge.

Collecting Kits

To make sample collecting and processing as simple and efficient as possible, collecting kits can be obtained from NHM.

Glossary

Collecting Event: A single date/time/location when specimens are collected.

Identifier: The field collector’s number or other reference identifier that clearly links each specimen or lot to collecting/locality data. For example:
Collected in 2013 by Adam Wall: “AW13-001”, “AW13-002”, etc.
Collected in 2014 at Marine Corps Base Camp Pendleton: “MCBCP14-001”, “MCBP14-002”, etc.

Preservative: Traditionally, specimens used exclusively for morphological studies have been fixed in 5–10% formalin (37% formaldehyde in solution, as commercially purchased, mixed with 90–95% water). Note that formalin fixation is no longer advised, since it makes the material unavailable for molecular genetic studies. 95% ethanol (not isopropyl alcohol or methanol) is now recommended.

Resting Egg: The spherical, dry, resting form of fairy shrimps are “resting eggs”, though they are often called “cysts”. The term “cyst” properly refers to an adult resting stage that is covered in a resistant outer shell.

Specimen Lot: Specimen(s) collected from a single locality during a single collecting event. The number of specimens in a lot may vary from as few as one (1) to many individuals. Individuals in a lot may be a single species or there may be many species (a mixed lot). As specimen identifications in a lot are refined (and the lot becomes further subdivided), they are still associated with the original locality and collecting (event) information.

This file last modified: 01 February 2018