Marine biologists from the Monterey Bay Aquarium Research Institute (MBARI) have described an unusually large and distinctive deep-sea crown jelly with coiled tentacles in Atollidae, a monogeneric family with 10 presently accepted species in the genus Atolla.
Laboratory photo of Atolla reynoldsi; diameter from margin to margin (excluding lappets) is 8.5 cm (3.3 inches) and tentacles were coiled in situ. Image credit: Rob Sherlock.
Members of the genus Atolla are found worldwide and can be abundant in deep water.
Atolla chuni, Atolla gigantea, and Atolla vanhoeffeni are the most recognizable.
Each of these have morphological characteristics that make them relatively easy to identify and are unique.
But others, even the common and widespread Atolla wyvillei, can be rather difficult to identify. Some characteristics thought to be species-specific have turned out to be less than helpful in separating out the species.
One feature researchers often use to identify Atolla is the single elongate, or hypertrophied, tentacle. One tentacle can stretch up to six times the diameter of the bell.
Observations from researchers in Japan suggest the single trailing tentacle helps a hungry Atolla snag siphonophores.
Over the past 15 years, MBARI researchers have observed and collected numerous specimens of three types of Atolla-like jellies that lack the typical trailing tentacle.
Now, they have collected sufficient details about morphological and molecular features to describe one of these three unique jellies: Atolla reynoldsi.
“We named this stunning new species in honor of Jeff Reynolds in recognition of the 4.3 million hours of service that he and other volunteers have contributed to the Monterey Bay Aquarium over the past 38 years,” said Dr. George Matsumoto, senior education and research specialist at MBARI.
“They have graciously given their time to educate the public about the wonders of the ocean.”
“Aquarium volunteers have been instrumental in raising awareness about the fragility of the ocean and inspiring the public to care about the health of the ocean.”
Atolla reynoldsi is relatively large compared to other Atolla species.
The largest specimen collected by the team was 13 cm (5.1 inches) in diameter, making this newly discovered species one of the largest in the genus.
Like other deep-sea crown jellies, Atolla reynoldsi has a furrowed bell.
A deep groove runs around the bell, separating the domed bell from the wide margin with thick segments, known as pedalia, containing finger-like lappets.
The edge of the bell resembles a crown, earning this group of jellies its regal name. The crown has warty papillae and spiked ridges.
The new species also has a distinct gut that is shaped like a Greek cross.
“Despite the lack of an adequate key, it is clear that that Atolla reynoldsi is molecularly distinct from the Atolla species that we have been able to collect and that it is morphologically distinct from all ten described Atolla species,” Dr. Matsumoto and colleagues said.
“The two additional types — Atolla species A and Atolla species B — may likewise be new species but we do not have enough samples at this time to make that claim.”
“All three types — Atolla reynoldsi, Atolla species A, and Atolla species B — may need to be placed into a new genus due to their distinct stomach morphology and the lack of a trailing tentacle, but until further work is completed, we recommend that they remain within the genus Atolla and that the family description be modified to include 16-62 rhopalia rather than 16-32 rhopalia.”
The discovery is reported in a paper in the journal Animals.
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George I. Matsumoto et al. 2022. Atolla reynoldsi sp. nov. (Cnidaria, Scyphozoa, Coronatae, Atollidae): A New Species of Coronate Scyphozoan Found in the Eastern North Pacific Ocean. Animals 12 (6): 742; doi: 10.3390/ani12060742
Source link: https://www.sci.news/biology/atolla-reynoldsi-10728.html
