Crabs, ecology and economy in Oman


This February 2019 video is about saving an Omani crab which had got caught in a fishing net.

From the Royal Netherlands Institute for Sea Research:

Crabs are key to ecology and economy in Oman

Importance of crabs should be considered when looking at increasing human pressure on Barr Al Hikman nature reserve

October 8, 2020

The intertidal mudflats of Barr Al Hikman, a nature reserve at the south-east coast of the Sultanate Oman, are crucial nursery grounds for numerous crab species. In return, these crabs are a vital element of the ecology, as well as the regional economy, a new publication in the scientific journal Hydrobiologia shows. ‘These important functions of the crabs should be considered when looking at the increasing human pressure on this nature reserve’, first author and NIOZ-researcher Roeland Bom says.

Blue swimming crab

The mudflats of Barr Al Hikman are home to almost thirty crab species. For his research, Bom, together with colleagues in The Netherlands and at the Sultan Qaboos University in Oman, looked at the ecology of the two most abundant species. Bom: ‘Barr Al Hikman is also home to the blue swimming crab Portunus segnis. That is the species caught by local fishermen. This crab uses the mudflats of Barr Al Hikman as nursery grounds.’

The counts of Bom and his colleagues show, that there are millions and millions of these crabs in Barr Al Hikman. They are food to hundreds of thousands of birds, both migrating species, as well as birds breeding in the area, such as crab plovers. The crabs live in holes in the ground. They forage on the seagrass beds that are still abundant in Barr Al Hikman. ‘Apart from the high primary production (algae) in Barr al Hikman, this reserve is also well suited for crabs because of the vastness of the area’, Bom assumes. ‘The slopes of the mudflats are very gentle, so at low tide, the crabs have an immense area at their disposition.’

Eco value

The value of the crabs is not just ecological, Bom stresses. “Local fishermen that catch the blue swimming crabs, distribute them not only through Oman, but also through the rest of the Arabian Peninsula and even to Japan. At approximately € 2,- per kilo, these crabs represent an important economic pillar, both under the region around Barr Al Hikman, as well as for the whole of Oman.’

Reserve

The protection of the reserve of Barr Al Hikman is limited to national legislation. Efforts to acknowledge this reserve under the international Ramsar-convention were never effectuated. There is, however, increasing human pressure on the mudflats of Barr Al Hikman, the authors describe, that would justify further protection. For example, there are well-developed plans to start shrimp farming around this intertidal area. ‘When looking at the cost and benefits of these activities, it is important to look at the role of this reserve in the local ecology, as well as in the broader ecology of the many migratory birds that use the area’, Bom says. ‘Moreover, our research shows that the unique ecosystem of Barr Al Hikman plays a key role in the economy as well.’

New freshwater crustacean species discovery in Iran


This 2019 video from Spain is called Phallocryptus spinosa en las Salinas de Roquetas de Mar.

From ScienceDaily:

New species of freshwater crustacea found in the hottest place on Earth

September 3, 2020

A new species of freshwater Crustacea has been discovered during an expedition of the desert Lut, known as the hottest place on Earth.

The newly identified species belongs to the genus Phallocryptus of which only four species were previously known from different arid and semiarid regions.

Dr Hossein Rajaei from the Stuttgart State Museum of Natural History and Dr Alexander V Rudov from Tehran University made the discovery during an expedition of Lut to better understand the desert’s ecology, biodiversity, geomorphology and paleontology.

Further scientific examinations of the specimens by co-author Dr Martin Schwentner, Crustacea specialist from the Natural History Museum of Vienna, stated that they belong to a new species of freshwater Crustacea.

Publishing their findings in Zoology in the Middle East, the biologists name the new species Phallocryptus fahimii, in honor of the Iranian conservation biologist, Hadi Fahimi, who took part in the 2017 expedition and sadly died in an airplane crash in 2018.

Dr Rajaei, an entomologist from State Museum of Natural History Stuttgart, who actually found the species in a small seasonal lake in southern part of the desert says the discovery is “sensational.”

“During an expedition to such an extreme place you are always on alert, in particular when finding water. Discovering crustaceans in this otherwise hot and dry environment was really sensational.”

The team’s study explains how Phallocryptus fahimii differs in its overall morphology and its genetics from all other known Phallocryptus species.

Dr Schwentner, who has worked with similar crustaceans from the Australian deserts in the past, adds: “These Crustaceans are able to survive for decades in the dried-out sediment and will hatch in an upcoming wet season, when the aquatic habitat refills. They are perfectly adapted to live in deserts environments. Their ability to survive even in the Lut desert highlights their resilience.”

The Lut desert — also known as Dasht-e Lut — is the second largest desert in Iran.

Located between 33° and 28° parallels and with its 51,800 km2 larger than Switzerland, this desert holds the current record for the highest ever-recorded surface temperature. Based on 2006 satellite measurements, the NASA reported a record surface temperature of 70.7°C, which more recently has been increased to even 80.3°C. Dark pebbles that heat up are one of the causes of these record temperatures. Mean daily temperatures range from -2.6°C in winter to 50.4°C in summer with annual precipitation not exceeding 30 mm per year.

Almost deprived of vegetation, the Lut desert harbors a diverse animal life, but no permanent aquatic biotops (such as ponds).

After rain falls, non-permanent astatic water bodies are filled including the Rud-e-Shur river from north-western Lut.

Here a diverse community of Archaea has been described but aquatic life in the Lut remains highly limited, which makes this find particularly rare.

Black sea spider crab re-described at last


This 2015 video is about a Macropodia sp. spider crab.

From ScienceDaily:

Neglected for over a century, Black sea spider crab re-described

September 1, 2020

Even though recognised in the Mediterranean Sea, the Macropodia czernjawskii spider crab was ignored by scientists (even by its namesake Vladimir Czernyavsky) in the regional faunal accounts of the Black Sea for more than a century. At the same time, although other species of the genus have been listed as Black sea fauna, those listings are mostly wrong and occurred either due to historical circumstances or misidentifications.

Now, scientists re-describe this, most likely, only species of the genus occurring in the Black Sea in the open-access journal Zoosystematics and Evolution.

The spider crab genus Macropodia was discovered in 1814 and currently includes 18 species, mostly occurring in the Atlantic and the Mediterranean. The marine fauna of the Black Sea is predominantly of Mediterranean origin and Macropodia czernjawskii was firstly discovered in the Black Sea in 1880, but afterwards, its presence there was largely ignored by the scientists.

After the revision of available type specimens from all available collections in the Russian museums and the Senckenberg Museum in Frankfurt-on-Main, as well as newly collected material in the Black Sea and the North-East Atlantic, a research team of scientists, led by Dr Vassily Spiridonov from Shirshov Institute of Oceanology of Russian Academy of Sciences, re-described Macropodia czernjawskii and provided the new data on its records and updated its ecological characteristics.

“The analysis of the molecular genetic barcode (COI) of the available material of Macropodia species indicated that M. czernjawskii is a very distinct species while M. parva should be synonimised with M. rostrata, and M. longipes is a synonym of M. tenuirostris,” states Dr Spiridonov sharing the details of the genus analysis.

All Macropodia species have epibiosis and M. czernjawskii is no exception: almost all examined crabs in 2008-2018 collections had significant epibiosis. It normally consists of algae and cyanobacteria and, particularly, a non-indigenous species of red alga Bonnemaisonia hamifera, officially reported in 2015 at the Caucasian coast of the Black Sea, was found in the epibiosis of M. czernjawskii four years earlier.

“It improves our understanding of its invasion history. Museum and monitoring collections of species with abundant epibiosis (in particular inachid crabs) can be used as an additional tool to record and monitor introduction and establishments of sessile non-indigenous species,” suggests Dr Spiridonov.

Ancient Triassic woodlouse discovery in Dutch Winterswijk


Winterswijk quarry with reconstruction drawing of Gelrincola winterswijkensis.  © Photo: Herman Winkelhorst, drawing by Erik-Jan Bosch (Naturalis Biodiversity Center)

Gelrincola winterswijkensis, A: Light microscope photo. B: Fluorescence microscope photo. C: Interpretative drawing. © Mario Schädel & prof. dr. Joachim Haug, Bulletin of Geosciences

Translated from Utrecht University in the Netherlands today:

Oldest woodlouse in the Netherlands discovered in Winterswijk quarry

A fossil woodlouse from the Triassic age, aged between 247 and 242 million years, has been discovered in the Winterswijk quarry. Never before has such an old woodlouse fossil been found in the Netherlands. It also turns out to be a new species. The find is extra special because fossil woodlice are extremely rare: until recently only nine species from the Triassic were known worldwide. The special fossil can be admired from 8 June on in Naturalis Biodiversity Center.

Woodlice do not only live in dark places or under stones: about half of all woodlouse species live in the sea. This in itself is not remarkable since woodlice are closely related to crabs and lobsters. The Winterswijk woodlouse also lived in the sea. The researchers named the new species Gelrincola winterswijkensis after the fossil site.

Gelrincola means ‘inhabitant of Gelderland province’.

The first woodlice appeared about 300 million years ago, during the Carboniferous. There are not many remains as ancient as Gelrincola winterswijkensis. Only ten species of woodlice are known from before the Triassic. More woodlice species are known from the eras after the Triassic. Today, more than ten thousand species of these crustaceans live.

The Winterswijk animal originates from the middle Triassic, a period of 247 to 242 million years ago. Back then Winterswijk was located on the edge of a large inland sea, the so-called Muschelkalk Sea. Along the coast of this Muschelkalk Sea there were extensive tidal plains where many remains of animals have been preserved in the lime mud. In Winterswijk you will find fossils from the sea as well as remains of animals that lived on land.

This yields a wide variety of fossils, including marine reptiles (such as Nothosaurus), fish, seashells, snails, ammonites, lobsters, a horseshoe crab, plant remains, pollen grains, footprints of terrestrial reptiles, and even fossil insects. So now a marine woodlouse can be added to this fossil biodiversity. This creates an increasingly complete picture of the ecosystem of the time. …

In our country, rocks from that interesting period only occur in the Winterswijk quarry.

This summer Naturalis Biodiversity Center and Utrecht University will continue to search for fossils there. A new visitors centre will be built next to the quarry, where the most important fossils from the quarry will be exhibited.

European and American lobsters crossbreeding, new research


This 2016 video from Britain is about European lobsters.

From the University of Exeter in England:

New test identifies lobster hybrids

May 11, 2020

Scientists have developed a test that can identify hybrids resulting from crossbreeding between European and American lobsters.

The Klu Klux Klan in the USA will consider these lobsters ‘communists’. As they claim that ‘race mixing’ is ‘communism’. As these picture show. They also show that Donald Trump’s anti-coronavirus health ‘Flu Klux Klan‘ consider social distancing ‘communist.’

American lobsters have occasionally escaped or been released into European waters after being imported for the seafood market.

Experts have long feared they could threaten European lobsters by introducing disease or establishing as an invasive species.

Hybridisation — when a “pure” species is threatened at a genetic level via interbreeding with a different but related species — had been less of a concern because lab studies suggested European and American lobsters were reluctant to mate.

However, when an American lobster female was found bearing eggs in a fjord in Sweden, University of Exeter researchers tested the offspring and found they were “clearly distinct” from both European and American lobsters.

“We had just developed a genetic test for seafood traceability that could separate any American lobsters mislabelled as more expensive European equivalents once they’ve been cooked and shell colouration is no longer a useful indicator of the species,” said Dr Charlie Ellis, of the University of Exeter.

“What we found when we tested these offspring is that they came out exactly in the middle of this separation — half American and half European — so these lobsters were hybrids.”

This has potentially concerning implications for the lobster industry and conservation efforts, and Dr Ellis says further research is required to assess the extent of the threat.

“Until recently, it was thought that American and European lobsters would avoid crossbreeding, but this introduced American female has mated with a native European male, probably because she was unable to find an American male,” he said.

“We now need to check whether any mature adult hybrids are fertile, because if they are then they have the ability to spread these unwanted American genes far and wide across our native lobster stocks.”

Working with collaborators from the University of Gothenburg who originally found the hybrid egg clutch, the researchers say their study, published in the journal Scientific Reports, highlights the vital use of genetics to distinguish hybrid lobsters which might look almost identical to a pure strain.

“It is particularly concerning that we seem to have found American lobster genes in one of our lobster reserves,” said Linda Svanberg of the Gothenburg team.

“The better news is we now have this genetic tool to test lobsters or their eggs for hybridisation,” added Dr Jamie Stevens, leader of the research which was funded by an EU grant through the Agritech Cornwall scheme, “so we can use it track the spread of these ‘alien’ genes to assess how big a threat this presents to our native lobster species.”

The team advise that, for a range of conservation reasons including potential contact with American lobsters, it is important that the general public never release a marketed lobster back into the wild, even our native species.

Dr Tom Jenkins said: “Although we appreciate that all animal-lovers have concern for the fate of individual animals, in this case the rescue of one animal might endanger the health of the entire wild population, so once a lobster has entered the seafood supply chain that’s where it should stay.”

How barnacles survive, video


This 22 April 2020 video from the USA says about itself:

How do barnacles survive environmental changes? Long-term work by a Brown University research team, with funding from the National Science Foundation, has confirmed that a central metabolic protein Mpi and the gene encoding the protein is what helps the barnacle survive extreme environmental changes.

Different versions of the Mpi enzyme are present at different levels, depending on where the barnacles have settled in the rocky shoreline. One form performs well under high stress, like on a hot day at low tide; the other form does better under low stress. This allows barnacles to survive and prosper in fluctuating extremes and has prepared them for success in an ever-changing environment.

Miocene fossil crab discovery in New Zealand


This 8 April 2020 video says about itself:

Man finds 12-million-year-old fossil, then spends 15 hours to expose crab hidden in stone

This timelapse footage shows an amateur palaeontologist uncovering an ancient crab fossil that he says is “12-million-years-old.”

The fossil, found on a beach in Christchurch, is encased in rock and Morne (Mamlambo on YouTube) carefully picks it away revealing the crab’s claws and shell.

Morne told Newsflare: “I found a fossil crab on a beach in New Zealand and then used an air scribe to remove the rock to show the fossil crab. It took about 10 hours and I made a timelapse of it.

“It [the fossil] is dated by the age of the rock it is found in, Miocene era in this case. The rock layers have been dated by some geologists using a variety of techniques, I use that information to date it. It isn’t very specific, rather a range.

“The species is a Tumidocarcinus giganteus. Found in New Zealand.”

How mantis shrimp find their way home


This 29 May 2019 video says about itself:

Mantis Shrimp Packs a Punch | Predator in Paradise

Armed with the most sophisticated vision and fastest strike of any predator on Earth, the mantis shrimp is an unexpected threat.

From the University of Maryland Baltimore County in the USA:

How do mantis shrimp find their way home?

April 9, 2020

Summary: New research indicates mantis shrimp use path integration to find their way back to their burrows after leaving to seek food or mates. That means they can track their distance and direction from their starting point. A series of creative experiments revealed that to do that, they rely on a hierarchy of cues from the sun, polarized light patterns, and their internal senses.

Mantis shrimps have earned fame for their powerful punching limbs, incredibly unusual eyes, and vivid exoskeletons. And, it turns out, they’re also really good at finding their way home. Through a series of painstaking experiments with these often-uncooperative creatures, Rickesh Patel has produced new findings on mantis shrimp navigation, published this week in Current Biology.

Patel, a Ph.D. candidate in biological sciences at UMBC, found that the species of mantis shrimp he investigated relies on the sun, patterns in polarized light, and internal cues — in that order — to navigate directly back to their non-descript burrows. These straight-line returns often follow forays that meander and zig-zag as the shrimp looks for a meal or a mate. The ability to get home quickly comes in handy when seeking shelter in the presence of predators, or a perceived one, as Patel noted on his first research fieldwork expedition.

After his first year at UMBC, Patel traveled with Tom Cronin’s lab to Lizard Island in the Great Barrier Reef to collect mantis shrimp for study. “As soon as they notice you, they’ll turn around and zip straight to some sort of shelter,” Patel says. Like a true scientist, “That got me wondering how they go about finding their way home.”

A crucial starting point

Scientists have written a great deal on navigation in other species — primarily bees, ants, and mice — but Patel’s is the first work on navigation in mantis shrimp.

First, Patel had to find a behavior he could work with to test ideas about how mantis shrimp navigate. So he created a small arena with an artificial shrimp burrow buried in sand. He placed the shrimp in the arena, and to his delight, the mantis shrimp was happy to occupy the small section of PVC pipe. Then he placed a piece of food at a distance from the burrow. He watched as the shrimp left its burrow, meandered until it found the food, and then returned to its burrow in a fairly straight line.

From those initial observations, Patel hypothesized that mantis shrimps use a process called path integration to find their way home. In other words, they are somehow able to track both their distance and direction from their burrow.

“That was probably the most exciting part of the experiments for me, because I knew I had a really robust behavior that I could work with,” Patel says. “Everything I did really extended from that initial point.”

Sunshine surprise

After that first discovery, the challenging work began, to figure out what cues the animals were using to determine the path home.

Patel built eight much larger arenas, each about 1.5 meters in diameter, to run his experiments. The first question he asked was whether the shrimp were using internal or external cues to go home.

To test that, Patel created a setup that rotated the animal 180 degrees as it retrieved the food. If the shrimp was using external cues to remember its distance and direction from home, it would still head in the right direction. If it was using internal cues, based on the orientation of its own body, it would head in the opposite direction. In the first round of trials, the animals consistently headed in the exact opposite direction.

“That was really cool, but it didn’t make a lot of sense,” Patel says, “because an internal compass is going to be a lot less accurate than something that is tied to the environment.” Then it hit him: “We just happened to have a really overcast week when I did these experiments, so I waited until we had a clear day, and then every time, they went right back home.”

Putting together the puzzle

Patel realized that his experiment perfectly demonstrated the hierarchy of cues used by the animals. They used external cues first, but when those weren’t available, they used internal cues.

That was the beginning of a long series of creative experiments that further teased out how these animals navigate. When Patel used a mirror to trick the animals into thinking the sun was coming from the opposite direction, they went the wrong way. This indicated they use the sun as a primary cue. When it was cloudy but not totally dark, they used polarization patterns in light, which are still detectable when it’s overcast. And when the sky was completely covered, they reverted to their internal navigation system.

A varied skillset

For Patel, creating the experimental arenas — essentially, the shrimp obstacle course — was almost as fun as getting the results. “That’s something I really enjoy — building things, creating things,” he shares. Patel studied art and biology as an undergraduate at California State University, Long Beach. “I think those skills lent me a hand in designing my experiments.”

Other skills Patel needed were patience and perseverance. “The animals will only behave maybe once a day, so if you scare the animal, you’ve lost that day,” he says.

For example, one of the experiments involved putting the animals on a track that pulled them to a new position, and seeing where they headed from there. “If the track is too jerky or goes too fast, they get scared and just don’t behave,” Patel says. “So I had to design the experiment so that it was so gentle they didn’t realize they were being moved.”

New questions

All of Patel’s patience has paid off with new findings that open up an array of future questions to answer. While path integration is well-documented in other species, mantis shrimp are the first to demonstrate the technique underwater. Looking up at the sky through water is a very different view than doing so through air, so Patel is curious how the animals’ process is different from other species.

Patel is also ultimately interested in the neural basis of navigation behavior, but “before you can investigate what’s happening in the brain, you have to understand what the animal’s doing,” he says. “So that’s why I really focused on the behavior work, to figure out what the animal is doing and what kind of stimuli are appropriate to show the animal that we can use to investigate its neurology.”

So far, other work has demonstrated that a brain region called the central complex has uncanny similarities between insects and mantis shrimps. This is especially interesting considering how far apart bees and shrimp are on the tree of life. The central complex is known to contribute to navigation in bees, so Patel is intrigued to learn more about its function in mantis shrimp. Alice Chou, another graduate student in the Cronin lab, is also investigating the brain structures of mantis shrimp.