Tag: Crustacea

First of a kind footage of a living stylodactylid shrimp filter-feeding at depth of 4826 m

Depths such as those at the Marianas Trench Marine National Monument are an extreme challenge for explorers, providing scarce information about their inhabitants, let alone their behavior.

While most of them are known from dead specimens gathered by trawls, a team of scientists, led by Dr. Mary Wicksten, Texas A&M University, USA, have recently retrieved footage of a living shrimp from the seafloor at a striking depth of 4826 m. The video presumably shows a species, previously known from a single broken specimen from the Coral Sea, while filter-feeding. The observation is published in the open access journal ZooKeys.

With the help of the remotely operated vehicle Deep Discoverer, part of the equipment the U.S. National Oceanographic and Atmospheric Administration (NOAA) have used in the “2016 Exploration of the Marianas” expedition, the researchers have obtained the first footage of a living deep-sea benthic shrimp of the Stylodactylidae family. In fact, the video was of such high-quality that the scientists believe they have recognised the shrimp at a species level (Bathystylodactylus bathyalis). This is also the deepest record for this group of shrimps.

Navigating through the seafloor, mostly thickly sedimented with clay-like particles easily disturbed into clouds, the Deep Discoverer spent nearly five hours traversing the bottom, letting the scientists at the shore observe depths ranging from 4840 to 4787 meters. When it reached 4826 m, it approached a tiny shrimp measuring about 120 mm in length.

As soon as they noticed it, the researchers moved the vehicle so that it could face the shrimp and take some detailed shots. At first, the crustacean was seen to stay immobile facing the current for a few minutes, before raising to its back legs and beginning to use the front ones to form what seems to be a “filter basket” that captures particles. Curiously, while such passive feeding behavior is known from some crabs, it has not been observed within any group of carideans, the shrimp infraorder where the studied species belongs.

NOAA’s ship Okeanos Explorer, administered through the Office of Exploration and Research and used in the deep-water expedition, is equipped with the remotely-operated vehicle Deep Discoverer and a camera sled. It relies on two maneuverable and four fixed video cameras, as well as 26 LED lamps. High-speed communication capabilities enable scientists to participate in ship operations via telepresence. Thanks to this technology, anyone with Internet access is able to observe live video feeds from and participate in real time via a private chat room and satellite teleconference line.

Okeanos Explorer is to be employed once again in 2017 to continue its explorative mission focused on deepwater areas of U.S. marine protected areas in the central and western Pacific.

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Original source:

Wicksten M, De Grave S, France S, Kelley C (2017) Presumed filter-feeding in a deep-sea benthic shrimp (Decapoda, Caridea, Stylodactylidae), with records of the deepest occurrence of carideans. ZooKeys 646: 17-23. https://doi.org/10.3897/zookeys.646.10969

New crab species shares name with 2 ‘Harry Potter’ characters and a hero researcher

While not much is known about the animals living around coral reefs, ex-Marine turned researcher Harry Conley would often take to the island of Guam, western Pacific Ocean, and dig deep into the rubble to find fascinating critters as if by magic learnt at Hogwarts. Almost 20 years after his discoveries and his death, a secret is revealed on the pages of the open access journal ZooKeys – a new species and genus of crab, Harryplax severus.

Having dug as deep as 30 m into Guam’s coral reef rubble, Harry Conley collected many specimens which stayed in his personal collection until the early 2000’s when Dr. Gustav Paulay, currently affiliated with the University of Florida, handed the specimens to the second author of the present study, Dr. Peter Ng, National University of Singapore, which resulted in many discoveries and publications. Among the lot, however, were two unusual specimens which were not studied until much later. Only recently did Dr. Peter Ng and his colleague at the National University of Singapore and lead author of the paper, Dr. Jose Christopher E. Mendoza, discover that they represent not only a new species, but also a new genus.

Having chosen the name Harryplax for the new genus, the two authors pay tribute to the crab’s original collector Harry Conley, who they describe as a “soft-spoken ex-Marine with a steely determination and a heart of gold,” and whose endeavours “have substantially advanced the cause of marine science”. The name is also meant to allude to the main protagonist in J. K. Rowling’s famous fantasy novel series, whose magical abilities the scientists liken to Conley’s knack for finding rare or new species. Of the two authors, Dr. Mendoza is the self-confessed ‘Potterhead’, who was not about to pass up the chance of naming a new crab after his favourite fictional characters. In his turn, Dr. Ng, who knew Harry Conley personally, was quite amused and happy to agree.

The crab’s species name, severus, is inspired by another ‘Harry Potter’ character – Professor Severus Snape, who despite being a central character in the series, keeps his background and agenda mysterious until the very end, when he reveals a key secret. Showing his real identity, the character, to the authors, is “just like the present new species which has eluded discovery until now, nearly 20 years after it was first collected”.

The new species is a tiny crab measuring less than a centimeter in both length and width and can be found deep in coral rubble or under subtidal rocks, perhaps also in cavities. To survive in the dark depths, the species has evolved with reduced eyes, well developed antennae, and long, slender legs. For the time being it is known only from the island of Guam.

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Original source:

Mendoza JCE, Ng PKL (2017) Harryplax severus, a new genus and species of an unusual coral rubble-inhabiting crab from Guam (Crustacea, Brachyura, Christmaplacidae). ZooKeys 647: 23-35. https://doi.org/10.3897/zookeys.647.11455

New species of pea-size crab parasitizing a date mussel has a name of a Roman god

Tiny crabs, the size of a pea, dwell inside the mantles of various bivalves, living off the food filtered by their hosts. A new species of these curious crustaceans has recently been reported from the Solomon Islands, where an individual was found to parasitise a large date mussel.

Because of the new pea crab’s characteristic large additional plate, covering its upper carapace, giving it the illusion of having two faces, it has been named after Janus, the Roman two-faced god. Discoverers Dr Peter Ng, National University of Singapore, and Dr Christopher Meyer, U.S. National Museum of Natural History, Smithsonian Institution, have their findings published in the open access journal ZooKeys.

Being only the second species in the genus (the first was from Malaysia), the new pea crab Serenotheres janus can be distinguished by its broader carapace and other features. It is cream-yellow in colour.

Both representatives of the genus are unique in having an additional large plate covering the upper side of the carapace. However, its purpose is still unknown. The two pea crabs are also the only known parasites of the rock-boring bivalves of the mytilid subfamily Lithophaginae.

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Original source:

Ng PKL, Meyer C (2016) A new species of pea crab of the genus Serenotheres Ahyong & Ng, 2005 (Crustacea, Brachyura, Pinnotheridae) from the date mussel Leiosolenus Carpenter, 1857 (Mollusca, Bivalvia, Mytilidae, Lithophaginae) from the Solomon Islands. ZooKeys 623: 31-41. doi: 10.3897/zookeys.623.10272

Crab from the Chinese pet market turns out to be a new species of a new genus

Shimmering carapaces and rattling claws make colourful freshwater crabs attractive to pet keepers. To answer the demand, fishermen are busy collecting and trading with the crustaceans, often not knowing what exactly they have handed over to their client.

Luckily for science and nature alike, however, such ‘stock’ sometimes ends up in the hands of scientists, who recognise their peculiarities and readily dig into them to make the next amazing discovery. Such is the case of three researchers from University of New South Wales, Australia, The Australian Museum, Sun Yat-sen University, China, and National Chung Hsing University, Taiwan, who have found a new species and even a new genus of freshwater crab, and now have it published in the open access journal ZooKeys.

Knowing about the growing demand for eye-catching freshwater crabs from southern China, the authors took a look at the ornamental fish market to eventually identify an individual with unusually structured male gonopod, which in crustaceans is a swimming appendage modified to serve as a reproductive organ. Having their interest drawn by the peculiar crab, lead author Chao Huang managed to persuade the fish dealer to let them survey the collection site located in northern Guangdong, southern China.

Despite superficial resemblance to an already existing freshwater crab genus, at second glance, the crab turned out to be quite distinct thanks to a unique set of features including the carapace, the gonopod and the relatively long and slender legs. Once the molecular analyses’ results were also in, the authors had enough evidence to assign the freshwater crab as a species and even a genus new to science.

Being a primarily aquatic species, the new crab prefers the pools of limestone hillstreams, therefore its name Yuebeipotamon calciatile, where calciatile means ‘living on limestone’. To adapt to the habitat, the species seems to have developed its characteristic slender legs, which make it easier for the crab to climb and move around whenever the short-lived limestone hillstreams make it search for a new home.

The carapace of the new crab is usually coloured in maroon to dark brown, while the claws and legs are reddish to purplish. Interestingly, the adults are much more vivid compared to the juveniles.

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Original source:

Citation: Huang C, Shih H-T, Mao SY (2016) Yuebeipotamon calciatile, a new genus and new species of freshwater crab from southern China (Crustacea, Decapoda, Brachyura, Potamidae). ZooKeys 615: 61-72. doi: 10.3897/zookeys.615.9964

Sir Elton John is the inspiration behind the name of a new coral reef crustacean species

While exploring the remote coral reefs of Raja Ampat in Indonesia, Dr. James Thomas from the Halmos College of Natural Sciences and Oceanography, Florida, and his colleagues from Naturalis Natural History museum in the Netherlands, stumbled across a small but extraordinary crustacean living inside another reef invertebrate in a commensal association (without causing any harm, nor benefit to its host).

In his amazement to the amphipod’s unusual form, Dr. Thomas called it L. eltoni after musician and actor Sir Elton John. The research is available in the open access journal ZooKeys.

“I named the species in honour of Sir Elton John because I have listened to his music in my lab during my entire scientific career,” the lead author explains. “So, when this unusual crustacean with a greatly enlarged appendage appeared under my microscope after a day of collecting, an image of the shoes Elton John wore as the Pinball Wizard came to mind.”

Taxonomists, scientists who study and name new species, have the choice to pick names that are relevant to locations, features of the animal, or people the scientist admires.

In an interesting twist L. eltoni is now reported from Hawaiian waters as an invasive species. “Several years ago I was contacted by scientists from the Bishop Museum in Honolulu to help identify an unusual amphipod they had collected,” said Dr. Thomas. It proved to be the same species as the one from Indonesia. The most likely scenario for its introduction into Hawaiian waters was as a hitchhiker inside its host sponge or tunicate that was attached to a large floating drydock transported to Hawaii from Subic Bay, Philippines. Recent studies by Dr. Thomas in the Philippines during a California Academy of Science expedition in 2014 have shown this new species is also found there.

Marine animals can have unknown effects when transported to other ecosystems where they can compete with native species. In most cases these “invasions” go unnoticed. However, because scientists at the Bishop Museum had established a baseline of species over the years the presence of this invasive amphipod was quickly noted.

“Such studies show the importance of regular environmental monitoring, especially in tropical environments,” commented the scientist. He also pointed out that even though their tiny size, crustaceans such as L. eltoni provide crucial information about reef health.

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Original source

Thomas J. D. (2015) Leucothoe eltoni sp. n., a new species of commensal leucothoid amphipod from coral reefs in Raja Ampat, Indonesia (Crustacea, Amphipoda). ZooKeys 518: 51-66. doi: 10.3897/zookeys.518.9340

New Indonesian crayfish species escapes the decor market to become a freedom fighter

With its orange to greenishly orange motley tip, the new crayfish species has been long-confused with its relatives by the tradesmen who have been collecting them for ornamental purposes. Being exported to countries in Europe, East Asia and America C. snowden specimens inevitably landed in the hands of the scientists from Lukhaup’s team who eventually recognised and proved them as a new crayfish species. Their research is available in the open-access journal ZooKeys.

Although the new crayfish species has probably been sold along with its motley relatives under another name for decades, the scientists figured that it is in fact easily distinguishable by its shape of body and colouration. In order to prove it as a separate species, the team used sequence divergence as well.

Having travelled across the world from its so far only known locality, West Papua, New Guinea, the new freshwater crustacean was given the name of the controversial former CIA employee and government contractor Edward Snowden. Its ‘godfather’ is famous for leaking secretive information from the U.S. National Security Agency, which later led him to a continuous search for political asylum. The authors speak of him as an “American freedom fighter” with “achievements in defence of justice, and freedom.”

In their conclusion the authors note that there could be potential threats to the new species. The freshwater crayfish is being collected in large numbers for both the ornamental fish global market and for food for the locals. Asked about the crustacean’s populations, the collectors spoke about a decline in the last few years.

“Clearly, the continued collection of these crayfish for the trade is not a sustainable practice, and if the popularity of the species continues, a conservation management plan will have to be developed, potentially including a captive breeding program,” the researchers comment.

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Original source:

Lukhaup C, Panteleit J, Schrimpf A (2015) Cherax snowden, a new species of crayfish (Crustacea, Decapoda, Parastacidae) from the Kepala Burung (Vogelkop) Peninsula in Irian Jaya (West Papua), Indonesia. ZooKeys 518: 1-14. doi: 10.3897/zookeys.518.6127

Underground gourmet: Selected terrestrial cave invertebrates and their meal preferences

Doubting whether terrestrial cave invertebrates feed on just anything they can find in the harsh food-wise environment underground, Dr. Jaroslav Smrz, fromCharles University, Vinicna, and his international team conducted a research in Slovakian and Romania caves. They tested the hypothesis that these species have rather negligible selection of food. Their microanatomical research into the gut content of several microwhip scorpions, oribatid mites, millipedes, springtails and crustaceans showed, however, that there is an evident meal preference among the species.

The results confirmed that the studied groups can adapt and develop under the pressure of extreme environmental factors. Therefore, the researchers concluded a low level of food competition. The study is available in the Subterranean Biology open-access journal.

The scientists studied the cells and tissues of the selected invertebrates and found out that the gut contents were nearly identical between the representatives of each group. This was the case even when the specimens had been collected from various locations. For instance, all microwhip scorpions proved a preference for cyanobacteria, while the mites favored the bacteria found in bat guano and the millipedes – fungi.

“The limited food offer seems to be used very unambiguously and thoroughly by the invertebrate communities,” the research team explained. “Therefore, the competition for food can be actually regarded as very low,” they concluded.

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Original source:

Smrz J, Kovac L, Mikes J, Sustr V, Lukesova A, Tajovsky K, Novakova A, Reznakova P (2015) Food sources of selected terrestrial cave arthropods. Subterranean Biology 16: 37-46. doi:10.3897/subtbiol.16.8609