“Don’t it always seem to go, that you don’t know what you have got till it’s gone.” Though Joni Mitchell may not be among the most celebrated of philosophers, her words still ring true, even for science (see also an earlier No Bones post in which we harness Joni’s wisdom to shine light on the importance of taxonomy). Since the 2010 Deepwater Horizon oil spill, interest in the benthic communities of the Northern Gulf of Mexico has increased dramatically. In recent years the United States Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA) have sponsored several scientific expeditions to explore the deep sea coral and cold methane seep habitats in the northern Gulf of Mexico, with the intention of learning more about their invertebrate communities. Scientists from IZ at NMNH have recently published a paper detailing their findings on the echinoid and holothurian fauna, based on specimens and images collected on seven of these expeditions. For those of you who do not speak fluent invertebrate taxonomy, echinoids and holothurians are animals from the echinoderm classes Echinoidea and Holothuroidea, aka sea urchins and sea cucumbers, respectively. The goal of these scientists, who include David Pawson, Martha Nizinski, Cheryl Lewis Ames and Doris Pawson, was to categorize the specimens and images collected on these expeditions and identify them to the lowest possible taxonomic level.
The combination of collections and in-situ (on-site) imaging is a power tool. While physical specimens are needed for more definitive taxonomic identifications, live images provide important details about animal color in life, behavior and environment, all of which are difficult to infer from museum specimens alone. In total, 186 specimens were collected using trawls and other collection gear, while images were taken from videos and photographs filmed by manned submersibles and ROV (remotely operated vehicles). These specimens were collected in a relatively small area off the coast of Mississippi and Louisiana at depths of 309-2549 meters, and were deposited into the IZ collections at NMNH.
In total, 21 species of holothurians and ten species of ecinoids were documented on these cruises based on images and/or specimen vouchers. Of them, ten are new to the documented fauna of the Gulf of Mexico, bringing the total number of echinoderms species known to inhabit the Gulf of Mexico to 522. Additionally, the research resulted in the proposal of a new genus and the description of a species entirely new to science.
The new sea cucumber genus name Oloughlinius was proposed to replace the existing genus name Meseres. If you have read our recent article on the World Register of Marine Species taxonomic database, you may recall that there are several reasons why a species name can be considered invalid. In this case, the proposed change of genus name is not due to misidentification, but rather because it was discovered that the genus name Meseres was already taken, in this case by a species of protozoa. Since genus names are supposed to be entirely unique, the genus name Oloughlinius was chosen as a replacement to honor Mark O’Loughlin an eminent scholar and echinoderm expert. Additional images from the Okeanos Explorer ROV depict what could represent another new species. However, it is difficult (and highly discouraged) to identify an organism as a new species in the absence of physical specimens which are required for morphological (and molecular) study.
The new species of sea cucumber named Myriotrochus ahearnae was found in the sediment at a depth of 1436-1574 meters. The specific epithet ahearnae was chosen to honor the late Cynthia (Cindy) Ahearn. who was a profoundly influential figure at the National Museum of Natural History where she had worked since 1973. As a Museum Specialist (IZ) she curated the museum’s extensive echinoderm collection, conducted important research on echinoderms and facilitated the research of so many others. She was also a pioneer in the Museum’s public education outreach program, and through her efforts she educated the public and hosted numerous international visiting researchers and students. Before her passing Cindy assisted in the identifications of the echinoderms specimens from this deep-sea exploration project, and was the first to recognize the specimens of Myriotrochus sea cucumber as a possible new species.
Cindy Ahearn is dearly missed, but she lives on through her work.
The oceans hold many mysteries for us, and they face an uncertain future. Let us hope that with the continued work of dedicated scientists we will be able to further explore and comprehend the things the sea and its denizens have to teach us.