Tag: Decapoda

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

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.

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 studied spirder crab species *Macropodia czernjawskii* in the wild, Tuaphat (near Gelendzhik), Caucasus, Black Sea.
Photo by Sergey Anosov

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.

The spider crab species *Macropodia czernjawskii* in the wild, Tuaphat (near Gelendzhik), Caucasus, Black Sea.
Photo by Sergey Anosov

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Original source:

Spiridonov VA, Simakova UV, Anosov SE, Zalota AK, Timofeev VA (2020) Review of Macropodia in the Black Sea supported by molecular barcoding data; with the redescription of the type material, observations on ecology and epibiosis of Macropodia czernjawskii (Brandt, 1880) and notes on other Atlanto-Mediterranean species of Macropodia Leach, 1814 (Crustacea, Decapoda, Inachidae). Zoosystematics and Evolution 96(2): 609-635. https://doi.org/10.3897/zse.96.48342

In a hole in a tunicate there lived a hobbit: New shrimp species named after Bilbo Baggins

Two new species of tiny symbiotic shrimps are described, illustrated and named by biology student at Leiden University Werner de Gier as part of his bachelor’s research project, supervised by Dr. Charles H. J. M. Fransen, shrimp researcher of Naturalis Biodiversity Center (Leiden, the Netherlands).

Inspired by the extremely hairy feet of one of the species, the authors decided that they should honour Middle Earth’s greatest halfling, Bilbo Baggins.

Aptly named Odontonia bagginsi, the new shrimp joins the lines of other species named after Tolkien’s characters such as the cave-dwelling harvestman Iandumoema smeagol, the golden lizard Liolaemus smaug and the two subterranean spiders Ochyrocera laracna and Ochyrocera ungoliant.

The newly described shrimps were collected during the Ternate expedition to the Indonesian islands of Tidore and Ternate, organised by Naturalis Biodiversity Center and the Indonesian Institute of Sciences (LIPI) in 2009.

Typically for the Odontonia species, the new shrimps do not reach sizes above a centimetre in length, and were found inside tunicates. It is believed that these symbiotic crustaceans are fully adapted to live inside the cavities of their hosts, which explains their small-sized and smooth bodies.

Unlike most Odontonia species, which live inside solitary tunicates, the new species Odontonia plurellicola was the first one to be associated with a colonial tunicate. These tunicates have even smaller internal cavities, which explains the tiny size of the new species.

To determine the placement of the new species in the tree of life, the scientists compared the shrimps’ anatomical features, including the legs, mouthparts and carapace. As a result, they were assigned to Odontonia. Further, the available genetic information and Scanning Electron Microscope (SEM) images of the unusual feet of the newly discovered shrimp provided a new updated identification key for all members of the species group.

“Being able to describe, draw and even name two new species in my bachelor years was a huge honour. Hopefully, we can show the world that there are many new species just waiting to be discovered, if you simply look close enough!” says Werner de Gier, who is currently writing his graduate thesis at Naturalis Biodiversity Center and working together with Dr. Charles Fransen on crustaceans.

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Original source:

de Gier W, Fransen CHJM (2018) Odontonia plurellicola sp. n. and Odontonia bagginsi sp. n., two new ascidian-associated shrimp from Ternate and Tidore, Indonesia, with a phylogenetic reconstruction of the genus (Crustacea, Decapoda, Palaemonidae). ZooKeys 765: 123-160. https://doi.org/10.3897/zookeys.765.25277

Five new blanket-hermit crab species described 130 years later from the Pacific

A blanket-hermit crab grasping an anemone.

Since 1888, a lone crab species living in an extraordinary symbiosis has been considered to be one of its kind

At the turn of the twentieth century, two independent marine scientists – JR Henderson in 1888, and A Alcock in 1899, described two unusual blanket-hermit crabs from the Indo-West Pacific.

Unlike other hermit crabs, these extraordinary crustaceans do not search for empty shells to settle in for protection. Instead, they have developed a symbiotic relationship with sea anemones to cover their soft bellies. To do this, the crabs use highly specialized chelipeds to pull back and forth the anemone’s tissue to cover their soft bodies and heads whenever necessary – much like hiding under a blanket.

Among the numerous specimens collected during the famous HMS Challenger Expedition in 1874, there were two hermit crab specimens obtained from the Philippines. They amazed Henderson with their unusual physical characters, including an abdomen bent on itself rather than spirally curved, and the lack of any trace of either a shell or other kind of protective structure for their body.

As a result, in 1888, JR Henderson established a brand new genus and new species for it as Paguropsis typicus. The ending of the species name was subsequently grammatically corrected to Paguropsis typica.

A decade later, unaware of the previous discovery, A Alcock stumbled upon hundreds of hermit crab specimens off southern India, which exhibited quite spectacular behaviour. Having observed their symbiotic relations with sea anemones, the researcher also formally described in 1899 a new species and a new genus for his specimens.

However, shortly thereafter and upon learning of JR Henderson’s earlier work, A Alcock concluded that his hermit crab specimens and those of JR Henderson must be one and the same species, so the two scientific names were officially synonymized in 1901 in a publication with his colleague AF McArdle, with JR Henderson’s name taking precedence as required by the principle of priority set forth in the International Code of Zoological Nomenclature.

Now, 130 years later, an international team of scientists, led by invertebrate zoologist Dr Rafael Lemaitre of the National Museum of Natural History, Smithsonian Institution, USA, not only found that A Alcock’s Indian specimens were indeed a separate species, leading to the resurrection of its name as Paguropsis andersoni, but that blanket-hermit crabs are not as rare as previously thought.

In their recent publication in the open access journal ZooKeys, the biologists described a total of five new species and a new genus of closely related blanket-hermit crabs. Furthermore, they expect that other species are to be discovered, since there are many vast marine shelf areas and deep-sea habitats spread across the Indo-West Pacific yet to be sampled.

To develop their exceptional symbiosis with sea anemones, the blanket-hermit crabs have obviously needed just as extraordinary evolutionary adaptations. Perhaps the most remarkable of these are their specialized chelate fourth legs that allow for the crustaceans to effectively grab and stretch the thin-walled body of the anemones to cover themselves. For five of the species, the scientists report and unusual grasping shape for this cheliped that is reminiscent of bear claws, while in the other two the shape resembles ice-block tongs.

Unfortunately, the identity of the sea anemone species involved in the symbiotic relationship with any of the studied blanket-hermit crabs is currently uncertain, and their biology remains unknown.

A blanket-hermit crab 'wearing' an anemone. — A blanket-hermit crab ‘wearing’ an anemone.

So far, the genus described by JR Henderson as Paguropsis, contains five species distributed in the subtropical and tropical Indo-West Pacific, and living at depths ranging from 30 to 1125 m. These include the two species discovered in the 19th century, and three new species, one of which, Paguropsis gigas, is the largest known blanket-hermit crab that reaches a body size of 15 cm when fully stretched (a large size by hermit crab standards).

For two of the newly discovered hermit crabs, the new genus Paguropsina is erected to reflect the numerous similarities between the two species and their Paguropsis relatives. The Latin suffix -ina refers to the comparatively smaller size of the two species. Both blanket-hermit species of Paguropsina are found in the subtropical and tropical western Pacific at depth between 52 and 849 m.

“Here there is no shell to play the part of ‘Sir Pandarus of Troy,’ but the sea-anemone settles upon the hinder part of the young hermit-crab’s tail, and the two animals grow up together, in such a way that the spreading zoophytes form a blanket which the hermit can either draw completely forwards over its head or throw half-back, as it pleases,” Alcock once eloquently described his marine discovery.

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Original source:

Lemaitre R, Rahayu DL, Komai T (2018) A revision of “blanket-hermit crabs” of the genus Paguropsis Henderson, 1888, with the description of a new genus and five new species (Crustacea, Anomura, Diogenidae). ZooKeys 752: 17-97. https://doi.org/10.3897/zookeys.752.23712

New species of crab with unusual outgrowths has its name written in the stars

A new species of crab with star-shaped tubercles all over its body has been collected from red coral beds during a survey at a small seamount by Peng-Chia-Yu Island, Taiwan. It has also been found in the Philippines. It is described in the open access journal ZooKeys.

This astonishing creature is distinct with its carapace and chelipeds covered in pointy protrusions. Interestingly, these change with age, becoming shorter, blunter and mushroom-shaped to resemble wart-like outgrowths and granules. Regardless of their sex, as the crabs grow larger, their carapaces also get proportionately rounder and wider.

The curious protuberances on the bodies reminded the research team of Dr. Peter Ng, National University of Singapore, and Dr. Ming-Shiou Jeng, Biodiversity Research Center, Academia Sinica, Taiwan, of stars. Hence, the crab was given the name Pariphiculus stellatus, where stellatus translates as ‘starry’ from Latin.

The colouration of P. stellatus varies among specimens. While predominantly orange with white patches, their shade could be either dull, pale or intense. The white spots might cover some of the protrusions or extend over most of the body. The underside of the body is dirty white to light brown.

Another rare crab species, Acanthodromia margarita, has been reported for the first time from Taiwan in the same study, having previously been known from the Andaman Sea in the eastern Indian Ocean, Japan and the Philippines. The collected female specimen is one of the largest representatives of the species known so far.

“With their bright orange to pink bodies, these hedgehog-like crabs are truly striking in life!” says Dr. Peter Ng.

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Original source:

Ng PKL, Jeng M-S (2017) Notes on two crabs (Crustacea, Brachyura, Dynomenidae and Iphiculidae) collected from red coral beds in northern Taiwan, including a new species of Pariphiculus Alcock, 1896. ZooKeys 694: 135-156. https://doi.org/10.3897/zookeys.694.14871

Behind Green Eyes: New species of deep-water hermit crab finds itself unusual shelters

‘Green-eyed hermit crab’ is the common name for a new species recently discovered off the West Coast of South Africa. Apart from its magnetic stare, however, there is a number of characteristic morphological traits and an unusual home preference that all make the crustacean unique.

Formally named after the University of Cape Town (UCT) alumnus Dr Lara Atkinson, the new hermit crab Paragiopagurus atkinsonaeis described by PhD candidate Jannes Landschoff, UCT, and Dr Rafael Lemaitre, Smithsonian Institution, USA, in the open access journal ZooKeys.

The Green-eyed hermit crab measures merely 70 mm in length and sports a coloration of mottled orange nuanced with cream to white. Among its distinct traits is the significant sexual dimorphism, where the males grow much larger right chelipeds in comparison to females.

Much like other hermit crabs in its family (Parapaguridae), the little crustacean does not use the shells of other molluscs to shelter its vulnerable body, but rather finds a home in the soft, polypy masses built from sand and material created by sea anemones which go on to live on the backs of these crabs in an amazing symbiosis.

“So, when you hold it [the hermit crab], it’s just organic material glued together with some sand,” explains Jannes in the UCT’s announcement about their discovery.

“Even more curiously, parapagurids start off in the usual way, occupying a tiny gastropod shell. But these eventually become deposited within this non-calcified ‘amalgam’ created by the anemones. As the hermit crab grows, its live ‘shell’, or carcinoecia, grows with it.”

The new species was discovered during a three-week survey back in 2013, conducted by the Department of Forestry and Fisheries and the South African Environmental Observation Network in the shallower deep waters (199 m to 277 m) off the West Coast of South Africa. Lara was on board one of the vessels when an unusual green-eyed crab turned up among the numerous specimens collected in one of the trawls. It was at that moment that she noticed that there was something peculiar about it and sent it for identification.

Restricted to a surprisingly small area for no obvious reason, the new species might be just bringing up some very important conservation messages.

“The area isn’t noticeably biologically or oceanographically distinct, but more detailed sampling from the area will tell us more about the habitat conditions. Future studies need to take this into account and give the area more research attention. If there’s something unusual about the site, you’d want to be careful, especially with mining operations along the West Coast,” says Jannes.

“Incidents like these are flags for future protection. The bottom line is we know so little about these offshore habitats from an ecological point of view. And if you’re planning for a marine protected area, you have to know what it is you’re protecting in that area.”

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Original source:

Landschoff J, Lemaitre R (2017) Differentiation of three common deep-water hermit crabs (Crustacea, Decapoda, Anomura, Parapaguridae) from the South African demersal abundance surveys, including the description of a new species of Paragiopagurus Lemaitre, 1996. ZooKeys676: 21-45. https://doi.org/10.3897/zookeys.676.12987

New species of terrestrial crab found climbing on trees in Hong Kong

A new species of terrestrial crab has been found to climb trees on the eastern coast of Hong Kong. All specimens spotted during the survey have been collected at a height of approximately 1.5 – 1.8 m, walking on the bark of the branches at ebbing and low tides. The species is described in the open access journal ZooKeys.

Among the crab’s characteristic traits are squarish predominantly dark brown carapace, very long legs and orange chelipeds. The species is less than a centimetre long, with the studied specimens measuring between 8 and 9 millimetres, irrespective of their sex. However, the chelipeds of the males appear stout, while in females they are distinctly more slender.

The scientists who found the new species (Haberma tingkok), Dr. Stefano Cannicci, the Swire Institute of Marine Science at the University of Hong Kong, and Dr. Peter Ng, National University of Singapore, have placed the new species in a small genus, which now contains merely three species. In fact, Dr. Peter Ng has been involved in the discovery of all of them. He also led the team that established the genus 15 years ago, having collected a small previously undescribed species of mangrove crab from Singapore.

The discovery of the tiny crustacean once again proves how little is known about the diversity of these crabs in Hong Kong. Furthermore, the mangroves that make for the habitat of the new species are under severe impact by both pollution and land reclamation, which underlines the urgent need for their conservation.

Earlier this year, Dr. Peter Ng teamed up with Dr. Jose Christopher Mendoza to describe another new species of crab, collected from the rubble at the island of Guam and named after two of the main characters in J. K. Rowling’s Harry Potter fantasy series.

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Original source:

Cannicci S, Ng PLK (2017) A new species of micro-mangrove crab of the genus Haberma Ng & Schubart, 2002 (Crustacea, Brachyura, Sesarmidae) from Hong Kong. ZooKeys 662: 67-78. https://doi.org/10.3897/zookeys.662.11908

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