Estimating somatic growth of fishes from maximum age or maturity

Two new data-limited methods to estimate somatic growth, applicable to species with indeterminate growth such as fishes or invertebrates.

Somatic growth rate is a central life-history parameter, especially in species like fishes or invertebrates which grow throughout their lives. It is needed in conservation and fisheries management but it can sometimes be tricky to estimate.

In a recent study published in the journal Acta Ichthyologica et Piscatoria, Dr. Rainer Froese of the Helmholtz Centre for Ocean Research proposes new simplified methods for somatic growth estimation.

A school of Jacks pass overhead at Viuda (Widow) dive site, in Coiba National Park, Panama, a UNESCO World Heritage site. Photo by LASZLO ILYES under a CC-BY 2.0 license.

Dr. Froese presents two new data-limited methods to estimate somatic growth from maximum length combined with either length or age at maturation or with maximum age. They are applicable to a wide range of species, sizes, and habitats. Using these new methods, growth parameter estimates were produced for the first time for 110 fish species.

“The growth estimates derived with the new methods presented in this study appear suitable for consideration and preliminary guidance in applications for conservation or management,” Dr. Froese points out in his study.

He goes on to suggest that journals accept growth estimates performed with the new methods as new knowledge, if they are the first for a given species.

In order to facilitate the conservation and management of natural resources, FishBase will continue to compile growth parameters, including results obtained with these new methods.

Research article:

Froese R (2022) Estimating somatic growth of fishes from maximum age or maturity. Acta Ichthyologica et Piscatoria 52(2): 125-133. https://doi.org/10.3897/aiep.52.80093

First-ever fish species described by a Maldivian scientist

Though there are hundreds of species of fish found off the coast of the Maldives, a mesmerizing new addition is the first-ever to be formally described by a Maldivian researcher.

Named after the country’s national flower, the species is added to the tree of life as part of the California Academy of Sciences’ global Hope for Reefs initiative

Originally published by the California Academy of Sciences

Though there are hundreds of species of fish found off the coast of the Maldives, a mesmerizing new addition is the first-ever to be formally described—the scientific process an organism goes through to be recognized as a new species—by a Maldivian researcher.

The new-to-science Rose-Veiled Fairy Wrasse (Cirrhilabrus finifenmaa), described in the journal ZooKeys, is also one of the first species to have its name derived from the local Dhivehi language, ‘finifenmaa’ meaning ‘rose’, a nod to both its pink hues and the island nation’s national flower.

Scientists from the California Academy of Sciences, the University of Sydney, the Maldives Marine Research Institute (MMRI), and the Field Museum collaborated on the discovery as part of the Academy’s Hope for Reefs initiative aimed at better understanding and protecting coral reefs around the world.

“It has always been foreign scientists who have described species found in the Maldives, even those that are endemic, without much involvement from local scientists. This time, it is different and getting to be part of something for the first time has been really exciting, especially having the opportunity to work alongside top ichthyologists on such an elegant and beautiful species,”

says study co-author and Maldives Marine Research Institute biologist Ahmed Najeeb.

First collected by researchers in the 1990s, C. finifenmaa was originally thought to be the adult version of a different species, Cirrhilabrus rubrisquamis, which had been described based on a single juvenile specimen from the Chagos Archipelago, an island chain 1,000 kilometers (621 miles) south of the Maldives. 

In this new study, however, the researchers took a more detailed look at both adults and juveniles of the multicolored marvel, measuring and counting various features, such as the color of adult males, the height of each spine supporting the fin on the fish’s back and the number of scales found on various body regions. These data, along with genetic analyses, were then compared to the C. rubrisquamis specimen to confirm that C. finifenmaa is indeed a unique species. 

Importantly, this revelation greatly reduces the known range of each wrasse, a crucial consideration when setting conservation priorities.  

“What we previously thought was one widespread species of fish, is actually two different species, each with a potentially much more restricted distribution. This exemplifies why describing new species, and taxonomy in general, is important for conservation and biodiversity management,”

says lead author and University of Sydney doctoral student Yi-Kai Tea. 

Despite only just being described, the researchers say that the Rose-Veiled Fairy Wrasse is already being exploited through the aquarium hobbyist trade. 

“Though the species is quite abundant and therefore not currently at a high risk of overexploitation, it’s still unsettling when a fish is already being commercialized before it even has a scientific name. It speaks to how much biodiversity there is still left to be described from coral reef ecosystems,”

says senior author and Academy Curator of Ichthyology Luiz Rocha, PhD, who co-directs the Hope for Reefs initiative.

Last month, Hope for Reefs researchers continued their collaboration with the MMRI by conducting the first surveys of the Maldives’ ‘twilight zone’ reefs—the virtually unexplored coral ecosystems found between 50- to 150-meters (160- to 500-feet) beneath the ocean’s surface—where they found new records of C. finifenmaa along with at least eight potentially new-to-science species yet to be described. 

This new-to-science Rose-Veiled Fairy Wrasse (Cirrhilabrus finifenmaa) became the first Maldivian fish to ever be described by a local researcher.
Photo by Yi-Kai Tea.

For the researchers, this kind of international partnership is pivotal to best understand and ensure a regenerative future for the Maldives’ coral reefs. 

“Nobody knows these waters better than the Maldivian people. Our research is stronger when it’s done in collaboration with local researchers and divers. I’m excited to continue our relationship with MMRI and the Ministry of Fisheries to learn about and protect the island nation’s reefs together,”

says Rocha says

“Collaborating with organizations such as the Academy helps us build our local capacity to expand knowledge in this field. This is just the start and we are already working together on future projects. Our partnership will help us better understand the unexplored depths of our marine ecosystems and their inhabitants. The more we understand and the more compelling scientific evidence we can gather, the better we can protect them,”

adds Najeeb.

***

Research article:

Tea Y-K, Najeeb A, Rowlett J, Rocha LA (2022) Cirrhilabrus finifenmaa (Teleostei, Labridae), a new species of fairy wrasse from the Maldives, with comments on the taxonomic identity of C. rubrisquamis and C. wakanda. ZooKeys 1088: 65-80. https://doi.org/10.3897/zookeys.1088.78139

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Learning more about vampire fish: first report of candiru attached to an Amazonian thorny catfish

For the first time, scientists report a vampire fish attached to the body of an Amazonian thorny catfish. Very unusually, the candirus were attached close to the lateral bone plates, rather than the gills, where they are normally found. Since the hosts were not badly harmed, and the candirus apparently derived no food benefit, scientists believe this association is commensalistic rather than parasitic. The research is published in the open-access journal Acta Ichthyologica et Piscatoria.

Guest blog post by Chiara C. F. Lubich, André R. Martins, Carlos E. C. Freitas, Lawrence E. Hurd and Flávia K. Siqueira-Souza

The Amazon River Basin is home to about 15% of all freshwater fish species known to science, and an estimated 40% yet to be named. These include some of the most bizarre fishes: the vampire fishes, locally known as candiru, members of the catfish subfamily Vandelliinae.). They survive by attaching themselves to the bodies of other fish and sucking on their blood, hence their common name. Yet, it was only recently that we found out that one candiru species, belonging to the genus Paracanthopoma, seems to be making use of its host in quite a different way.

During a sampling study of freshwater fish fauna in a lake of the Demeni River Basin, a left bank tributary of the Negro River, we found candirus attached to the surface of the body of an Amazonian species of a thorny catfish. By the end of the survey, we had observed a total of twenty candirus attached to the outside of the bodies of nine larger Doras phlyzakion, one or two per host. Very unusually, the candirus were attached close to the lateral bone plates, rather than the gills, where these fish are normally found.

Location of the study: Demeni River, left bank tributary of Negro River, Amazonas State, Brazil.

As a result of these observations, we recently published the first record of a candiru attached to the body surface of an Amazonian thorny catfish in an article in the open-access scholarly journal Acta Ichthyologica et Piscatoria.

Vampire fish have long and robust snouts, with strong dentary teeth that help them stay attached to the epidermis of their host and feed on its blood. However, when we performed a macroscopic analysis of the stomach contents of the preserved Paracanthopoma specimens, we were surprised to find no coagulated blood, nor flesh, skin or mucus. This might indicate an interaction between parasite and host that is more benign than usually attributed to vampire fish. 

Doras phlyzakion with vampire fish (Paracanthopoma sp.)  fixed into its epidermis close to the bony plates of the lateral line. Arrows: areas with reddish wounds.

We believe the association between candiru and host in this case might be commensalistic (where one organism benefits from another without harming it), rather than parasitic, because the hosts were not badly harmed, and the candiru apparently derived no food benefit. 

But what else would they seek on the back of Amazonian thorny catfish? One explanation could be that, since candirus are tiny and nearly transparent, they might be avoiding getting noticed by visual predators by riding on larger fish. Another hypothesis is that they could be using their big cousins to transport them over longer distances that they wouldn’t be able to cover themselves, eventually making it to safety or new food sources.

Research article:

Lubich CCF, Martins AR, Freitas CEC, Hurd LE, Siqueira-Souza FK (2021) A candiru, Paracanthopoma sp. (Siluriformes: Trichomycteridae), associated with a thorny catfish, Doras phlyzakion (Siluriformes: Doradidae), in a tributary of the middle Rio Negro, Brazilian Amazon. Acta Ichthyologica et Piscatoria 51(3): 241-244. https://doi.org/10.3897/aiep.51.e64324

Acta Ichthyologica et Piscatoria signs with Pensoft and moves to ARPHA

The scholarly publisher and technology provider Pensoft welcomes the latest addition to its diverse portfolio of scholarly outlets – the open-access, peer-reviewed journal Acta Ichthyologica et Piscatoria (AIeP), which publishes research in the fields of ichthyology and fisheries.

AIeP is an international scientific journal publishing articles in any aspect of ichthyology and fisheries concerning true fishes (fin-fishes), including taxonomy, biology, morphology, anatomy, physiology, pathology, parasitology, reproduction and zoogeography. The academic outlet, which was launched in 1970, favours research based on original experimental data or experimental methods, or new analyses of already existing data. AIeP is indexed by all major indexers, including Web of Science and Scopus. The journal’s first Impact Factor was released in 2010, and currently stands at 0.629 (2019).

The first 2021 issue of the the open-access, peer-reviewed international journal Acta Ichthyologica et Piscatoria is already online on a brand-new website

In joining the Pensoft portfolio, AIeP gets a brand-new user-friendly website with improved design and access to Pensoft’s self-developed full-featured platform ARPHA, which offers an end-to-end publishing solution from submission to publication, distribution and archiving. With features, such as papers available in semantically enhanced HTML and machine-readable XML formats, automated data export to aggregators, and web-service integrations with major global indexing databases, the easy-to-use, open-access platform ensures that published research is easy to discover, access, cite and reuse by both humans and machines all over the world.

AIeP’s first issue published with Pensoft features 14 scientifically diverse open-access articles on ichthyology and fisheries covering a wide geographic scope. Some of the issue’s most interesting reads explore the eating habits of the spotted rose snapper in the Gulf of California, offer the first underwater photograph of a rare scorpionfish in Japan, and record the first ever occurrence of the pharaoh cardinal fish in Libyan waters, in what constitutes the westernmost Mediterranean area of colonization of this non-indigenous species.

Amongst the published papers there are also practical suggestions for species conservation and sustainable fisheries management – for example, an evaluation of the size of freshwater fish in Bangladeshi wetlands recommends only harvesting fishes with a total length of over 8.80 cm.

Follow Acta Ichthyologica et Piscatoria on Facebook and Twitter.

Additional information

About ARPHA:

ARPHA is the first end-to-end, narrative- and data-integrated publishing solution that supports the full life cycle of a manuscript, from authoring to reviewing, publishing and dissemination. ARPHA provides accomplished and streamlined production workflows that can be customized according to the journal’s needs. The platform enables a variety of publishing models through a number of options for branding, production and revenue models to choose from.

About Pensoft:

Pensoft is an independent academic publishing company, well-known worldwide for its innovations in the field of semantic publishing, as well as for its cutting-edge publishing tools and workflows. In 2013, Pensoft launched the first ever end to end XML-based authoring, reviewing and publishing workflow, as demonstrated by the Pensoft Writing Tool (PWT) and the Biodiversity Data Journal (BDJ), now upgraded to the ARPHA Publishing Platform. Flagship titles include: Research Ideas and Outcomes (RIO), One Ecosystem, ZooKeys, Biodiversity Data Journal, PhytoKeys, MycoKeys and many more.

Contacts:

Wojciech Piasecki, Editor-in-Chief at AIeP

editor@aiep.pl

Lyubomir Penev, founder and CEO at Pensoft and ARPHA

l.penev@pensoft.net 

A new character for Pokémon? Novel endemic dogfish shark species discovered from Japan

A new endemic deep-water dogfish shark: Squalus shiraii, was discovered in the tropical waters of Southern Japan by an international team of scientists led by Dr. Sarah Viana from South African Institute for Aquatic Biodiversity. The finding brings the amount of spurdogs shark species inhabiting Japanese waters to six. The discovery is published in the open-access journal Zoosystematics and Evolution.

Newly discovered creatures can often be as impressive and exciting as the ones from the Japanese movies and shows. Many of those fictional characters, including inhabitants of the famous Pokémon universe, might have their analogues among the real animals native to Japan. Maybe, a new species of the dogfish shark published in the open-access journal Zoosystematics and Evolution is also “a real Pokémon” to be?

A new deep-water dogfish shark: Squalus shiraii, was discovered in the tropical waters of Southern Japan by an international team of scientists, led by Dr. Sarah Viana from South African Institute for Aquatic Biodiversity


 Map of the North-western Pacific Ocean, showing the geographical distribution of Squalus shiraii
Credit: Sarah Viana
License: CC-BY 4.0

The new shark has the body length of 59-77 cm and some unique characteristics such as tall first dorsal fin and caudal fin with broad white margins. Currently, the species is known exclusively as a Japanese endemic, occurring in the tropical shallow waters of Southern Japan in the North-western Pacific.


Squalus shiraii lateral view
Credit: Sarah Viana
License: CC-BY 4.0

Spurdogs represent commercially important for the world fish trade taxa. They are caught for a range of purposes: consumption of meat, fins and liver oil. Despite their high occurrence, the accurate identification data of species is scarce, population threats and trends remain unknown.

Japan currently represents one of the world’s leading shark fish trade countries, though, during the last decades the amount of shark catches is decreasing and over 78 elasmobranch species traded in Japanese shark fin markets are now evaluated as threatened.

The new species Squalus shiraii previously used to be massively misidentified with shortspine spurdog, due to the resembling shape of body, fins and snout length. However, there are some differences, defining the specificity of the new species.

Squalus shiraii has body brown in colour, postventral and preventral caudal margins whitish, dorsal and ventral caudal tips broadly white and black upper caudal blotch evident in adults. S. mitsukurii has body conspicuously black to dark grey and caudal fins black throughout with post-ventral caudal margin fairly whitish and black upper caudal blotch not evident in adults”, shares lead author Dr. Viana.

Scientists propose the name for the newly described species as Shirai’s spurdog in honour to Dr. Shigeru Shirai, the former Japanese expert of the group.

Original source:
Viana STFL, Carvalho MR (2020) Squalus shiraii sp. nov. (Squaliformes, Squalidae), a new species of dogfish shark from Japan with regional nominal species revisited. Zoosystematics and Evolution 96(2): 275-311. https://doi.org/10.3897/zse.96.51962

Contact:
Dr. Sarah Viana
Email: stviana@gmail.com


On the edge between science & art: historical biodiversity data from Japanese “gyotaku”

Japanese cultural art of ‘gyotaku’, which means “fish impression” or “fish rubbing”, captures accurate images of fish specimens. It has been used by recreational fishermen and artists since the Edo Period. Distributional data from 261 ‘Gyotaku’ rubbings were extracted for 218 individual specimens, roughly representing regional fish fauna and common fishing targets in Japan through the years. The results of the research are presented in a paper published by Japanese scientists in open-access journal Zookeys.

Japanese cultural art of ‘gyotaku’, which means “fish impression” or “fish rubbing”, captures accurate images of fish specimens. It has been used by recreational fishermen and artists since the Edo Period. Distributional data from 261 ‘Gyotaku’ rubbings were extracted for 218 individual specimens, roughly representing regional fish fauna and common fishing targets in Japan through the years. The results of the research are presented in a paper published by Japanese scientists in open-access journal Zookeys.

Historical biodiversity data is being obtained from museum specimens, literature, classic monographs and old photographs, yet those sources can be damaged, lost or not completely adequate. That brings us to the need of finding additional, even if non-traditional, sources. 

In Japan many recreational fishers have recorded their memorable catches as ‘gyotaku’ (魚拓), which means fish impression or fish rubbing in English. ‘Gyotaku’ is made directly from the fish specimen and usually includes information such as sampling date and locality, the name of the fisherman, its witnesses, the fish species (frequently its local name), and fishing tackle used. This art has existed since the last Edo period. Currently, the oldest ‘gyotaku’ material is the collection of the Tsuruoka City Library made in 1839.

Traditionally, ‘gyotaku’ is printed by using black writing ink, but over the last decades colour versions of ‘gyotaku’ have become better developed and they are now used for art and educational purposes. Though, the colour prints are made just for the means of art and rarely include specimen data, sampling locality and date.

In the sense of modern technological progress, it’s getting rarer and rarer that people are using ‘gyotaku’ to save their “fishing impressions”. The number of personally managed fishing-related shops is decreasing and the number of original ‘gyotaku’ prints and recreational fishermen might start to decrease not before long.

Smartphones and photo cameras are significantly reducing the amount of produced ‘gyotaku’, while the data from the old art pieces are in danger of either getting lost or diminished in private collections. That’s why the research on existing ‘gyotaku’ as a data source is required.

A Japanese research team, led by Mr. Yusuke Miyazaki, has conducted multiple surveys among recreational fishing shops in different regions of Japan in order to understand if ‘gyotaku’ information is available within all the territory of the country, including latitudinal limits (from subarctic to subtropical regions) and gather historical biodiversity data from it.

In total, 261 ‘gyotaku’ rubbings with 325 printed individual specimens were found among the targeted shops and these data were integrated to the ‘gyotaku’ database. Distributional data about a total of 235 individuals were obtained within the study.

The observed species compositions reflected the biogeography of the regions and can be representative enough to identify rare Red-listed species in particular areas. Some of the studied species are listed as endangered in national and prefectural Red Lists which prohibits the capture, holding, receiving and giving off, and other interactions with the species without the prefectural governor’s permission. Given the rarity of these threatened species in some regions, ‘gyotaku’ are probably important vouchers for estimating historical population status and factors of decline or extinction.

“Overall, the species composition displayed in the ‘gyotaku’ approximately reflected the fish faunas of each biogeographic region. We suggest that Japanese recreational fishers may be continuing to use the ‘gyotaku’ method in addition to digital photography to record their memorable catches” , concludes author of the research, Mr. Yusuke Miyazaki.


Gyotaku rubbing from the fish store in Miyazaki Prefecture
Credit: Yusuke Miyazaki
License: CC-BY 4.0

Gyotaku rubbing of the specimen from Kanagawa found in the shop in Tokyo
Credit: Yusuke Miyazaki
License: CC-BY 4.0

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Original source:

Miyazaki Y, Murase A (2019) Fish rubbings, ‘gyotaku’, as a source of historical biodiversity data. ZooKeys 904: 89-101. https://doi.org/10.3897/zookeys.904.47721

Wakanda Forever! Scientific divers describe new purple species of “twilight zone” fish from Africa

Named for Black Panther’s mythical nation of Wakanda, a dazzling new “Vibranium” Fairy Wrasse enchants with purple scales and a preference for deep, little-known mesophotic reefs up to 260 feet below the surface

Africa has new purple-clad warriors more than 200 feet beneath the ocean’s surface. Deep-diving scientists from the California Academy of SciencesHope for Reefs initiative and the University of Sydney spotted dazzling fairy wrasses—previously unknown to science—in the dimly lit mesophotic coral reefs of eastern Zanzibar, off the coast of Tanzania. 

Preserved specimen of Vibranium fairy wrasse (Cirrhilabrus wakanda) retains its striking coloration.
Photo by Jon Fong © 2018 California Academy of Sciences.

The multicolored wrasses sport deep purple scales so pigmented, they even retain their color (which is typically lost) when preserved for research. The scientists name this “twilight zone” reef-dweller Cirrhilabrus wakanda (common name “Vibranium Fairy Wrasse”) in honor of the mythical nation of Wakanda from the Marvel Entertainment comics and movie Black Panther. The new fish is described in the open-access journal Zookeys.

Female specimen of Vibranium fairy wrasse (Cirrhilabrus wakanda) in its natural habitat (Zanzibar). Photo by Luiz Rocha © 2018 California Academy of Sciences.

Yi-Kai Tea, lead author and ichthyology PhD student from the University of Sydney, says:

“When we thought about the secretive and isolated nature of these unexplored African reefs, we knew we had to name this new species after Wakanda. We’ve known about other related fairy wrasses from the Indian Ocean, but always thought there was a missing species along the continent’s eastern edge. When I saw this amazing purple fish, I knew instantly we were dealing with the missing piece of the puzzle.”

The Academy scientists say Cirrhilabrus wakanda’s remote home in mesophotic coral reefs—below recreational diving limits—probably contributed to their long-hidden status in the shadows of the Indian Ocean. 

A California Academy diver on an expedition in the Indian Ocean.
Photo by Bart Shepherd © 2018 California Academy of Sciences.

Therefore, Hope for Reefs’ scientific divers are highly trained for the dangerous process of researching in these deep, little-known mesophotic reefs, located 200 to 500 feet beneath the ocean’s surface. Accessing them requires technical equipment and physically intense training well beyond that of shallow-water diving. The team’s special diving gear (known as closed-circuit rebreathers) includes multiple tanks with custom gas blends and electronic monitoring equipment that allow the divers to explore deep reefs for mere minutes before a lengthy, hours-long ascent to the surface.

Dr. Luiz Rocha, Academy Curator of Fishes and co-leader of the Hope for Reefs, comments:

“Preparation for these deep dives is very intense and our dive gear often weighs more than us. When we reach these reefs and find unknown species as spectacular as this fairy wrasse, it feels like our hard work is paying off.”

California Academy’s “twilight zone” dive gear prepped for Zanzibar.
Photo by Luiz Rocha © 2018 California Academy of Sciences.

Using a microscope, the team examined the specimens’ scales, fin rays, and body structures. DNA and morphological analyses revealed the new fairy wrasse to be different from the other seven species in the western Indian Ocean as well as other relatives in the Pacific. The new species’ common name is inspired by the fictional metal vibranium, a rare, and, according to Rocha, “totally awesome” substance found in the nation of Wakanda. The Vibranium Fairy Wrasse’s purple chain-link scale pattern reminded the scientists of Black Panther’s super-strong suit and the fabric motifs worn by Wakandans in the hit film.

Precious life in deep reefs

In a recent landmark paper, the Academy team found that twilight zone reefs are unique ecosystems bursting with life and are just as vulnerable to human threats as their shallow counterparts. Their findings upended the long-standing assumption that species might avoid human-related stressors on those deeper reefs. The Hope for Reefs team will continue to visit and study twilight zone sites around the world to shed light on these often-overlooked ecosystems.

Newly described Pohnpei fish (Liopropoma incandescens). Photo by Luiz Rocha © 2018 California Academy of Sciences.

In addition to this new fish from Zanzibar, Rocha and his colleagues recently published descriptions of mesophotic fish from Rapa Nui (Easter Island) and Micronesia. Luzonichthys kiomeamea is an orange, white, and sunny yellow dwarf anthias endemic to Rapa Nui, and the basslet Liopropoma incandescens (another new species published today in Zookeys) inhabits Pohnpei’s deep reefs—a neon orange and yellow specimen collected from a rocky slope 426 feet beneath the ocean’s surface.  

“It’s a time of global crisis for coral reefs, and exploring little-known habitats and the life they support is now more important than ever,” concludes Rocha. “Because they are out of sight, these deeper reefs are often left out of marine reserves, so we hope our discoveries inspire their protection.”

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(Text by the California Academy of Sciences, USA)

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Research articles:

Tea YK, Pinheiro HT, Shepherd B, Rocha LA (2019) Cirrhilabrus wakanda, a new species of fairy wrasse from mesophotic ecosystems of Zanzibar, Tanzania, Africa (Teleostei, Labridae). ZooKeys 863: 85–96. https://doi.org/10.3897/zookeys.863.35580.

Pinheiro HT, Shepherd B, Greene BD, Rocha LA (2019) Liopropoma incandescens sp. nov. (Epinephelidae, Liopropominae), a new species of basslet from mesophotic coral ecosystems of Pohnpei, Micronesia. ZooKeys 863: 97–106. https://doi.org/10.3897/zookeys.863.33778.

New species of fish parasite named after Xena, the warrior princess

A study of parasitic crustaceans attaching themselves inside the branchial cavities (the gills) of their fish hosts was recently conducted in order to reveal potentially unrecognised diversity of the genus Elthusa in South Africa.

While there had only been one species known from the country, a new article published in the open-access journal ZooKeys adds another three to the list.

For one of them, the research team from North-West University (South Africa): Serita van der Wal, Prof Nico Smit and Dr Kerry Hadfield, chose the name of the fictional character Xena, the warrior princess. The reason was that the females appeared particularly tough with their characteristic elongated and ovoid bodies. Additionally, the holotype (the first specimen used for the identification and description of the previously unknown species) is an egg-carrying female.

Formally recognised as Elthusa xena, this new to science species is so far only known from the mouth of the Orange River, Alexander Bay, South Africa (Atlantic Ocean). It is also the only Elthusa species known to parasitise the intertidal Super klipfish (Clinus supercilious). In fact, this is the first time an Elthusa species has been recorded from any klipfish (genus Clinus).

To describe the new species, the scientists loaned all South African specimens identified as, or appearing to belong to the genus Elthusa from both the French National Museum of Natural History (Paris) and the Iziko South African Museum (Cape Town).

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Original source:

van der Wal S, Smit NJ, Hadfield KA (2019) Review of the fish parasitic genus Elthusa Schioedte & Meinert, 1884 (Crustacea, Isopoda, Cymothoidae) from South Africa, including the description of three new species. ZooKeys 841: 1-37. https://doi.org/10.3897/zookeys.841.32364

How did the guppy cross the ocean: An unexpected fish appears on a volcanic archipelago

While people tend to describe tropical oceanic islands as ‘paradises on Earth’ and associate them with calm beaches, transparent warm waters and marvellous landscapes, archipelagos are often the product of a fierce natural force – volcanoes which erupt at the bottom of the sea.

Because of their origin, these islands have never been connected to the mainland, thereby it is extremely difficult for species to cross the ocean and populate them.DSCN1337

One such species – the South American guppy (Poecilia vivipara) – is a small freshwater fish which looks nowhere equipped to cross the distance between the mainland and the Fernando de Noronha oceanic archipelago in Northeast Brazil.

Nevertheless, the research team of PhD student Waldir M. Berbel-Filho and his professor Dr. Sergio Lima from Universidade Federal do Rio Grande do Norte recorded the species from a local mangrove on the island. The question that immediately sprang to the minds of the scientists was: ‘Where did the guppies come from and how did they get to Fernando de Noronha?’

To answer these questions, the scientists sequenced a gene of the guppies’ DNA to analyze potential signatures of the island colonization left in the fish DNA. As a result, they concluded that the isolated population was in fact closely related to the fish inhabiting the closest continental drainages.

However, this evidence was not enough to explain how the species turned up on the island in the first place. Was it natural colonization, or rather human introduction?

Poecilia vivipara Sergipe-2

The most likely scenario, according to the team, leads back to about 60 years ago when the American military had their WWII bases positioned at both Fernando de Noronha and Natal – the closest continental city. Indeed, the soldiers suggested to bring guppies to the island in an attempt to control mosquito population (in this region, guppies are commonly placed in water reservoirs to eat mosquito larvae).

On the other hand, natural dispersion cannot be completely excluded. The biologists remind that, apart for their exuberant colours and shapes, the guppies are well known for their capacity to resist to a wide range of environmental conditions. It could be that a set of circumstances occurring together, such as a favourable sea current, physiological adaptation and a bit of luck, might have brought the guppies to the archipelago.

Regardless of their means of transportation,” argue the authors, “this guppy population represents a valuable lesson on how small populations manage to colonize and thrive in isolated environments.

Despite being visited by thousands of people every year, some of the most intriguing secrets of tropical islands may still be hidden in the DNA of their inhabitants,” they conclude. “These ‘paradises on Earth’ are capable of simultaneously filling our hearts with beauty and our minds – with knowledge.”

 

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Original source:

Berbel-Filho WM, Barros-Neto LF, Dias RM, Mendes LF, Figueiredo CAA, Torres RA, Lima SMQ (2018) Poecilia vivipara Bloch & Schneider, 1801 (Cyprinodontiformes, Poeciliidae), a guppy in an oceanic archipelago: from where did it come? ZooKeys 746: 91-104. https://doi.org/10.3897/zookeys.746.20960

Chinese scientists discover a new species of catfish in Myanmar

During a survey of the freshwater fishes of the Mali Hka River drainage in the Hponkanrazi Wildlife Sanctuary, Myanmar, scientists Xiao-Yong Chen, Tao Qin and Zhi-Ying Chen, from the Chinese Academy of Sciences (CAS), identified a new catfish species among the collected specimens. It is distinct with a set of morphological features including its mouthparts and coloration. The discovery is published in the open access journal ZooKeys.

The new catfish belongs to a genus (Oreoglanis) of 22 currently recognised species. They are characterised with unusual teeth. While pointed in the upper and the back of the lower jaw, the teeth at the front of the lower jaw are shorter and broad. The latter are placed in a continuous dent. Out of the 22 species of the genus, there are only two known to live in Myanmar.

The new catfish, scientifically named Oreoglanis hponkanensis, has a moderately broad and strongly depressed head and body, and small eyes. The species is predominantly brown in colour, with light yellow belly and several yellowish patches across the body. Noticeable are also two round, bright orange patches in the middle of the fin.

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Original source:

Chen X-Y, Qin T, Chen Z-Y (2017) Oreoglanis hponkanensis, a new sisorid catfish from north Myanmar (Actinopterygii, Sisoridae). ZooKeys 646: 95-108. https://doi.org/10.3897/zookeys.646.11049