Cercarial dermatitis, also known as swimmer’s itch or clam-digger’s itch, is caused by the larvae of blood flukes that are parasites of birds or mammals. When these larvae, called cercariae, penetrate human skin, they trigger an allergic reaction within 10-15 hours that takes about a week to heal. Unable to mature into adults, the larvae then die on the skin. The gravity of an outbreak depends on how humans and birds or mammals come in contract with the aquatic environment, but people engaged in water activities, such as farmers, fishermen, and agricultural workers, are most likely to be affected.
Between August and October 2020, a cercarial dermatitis outbreak with 359 confirmed cases occurred in Chana district, Songkhla Province, South Thailand. It mostly affected rice farmers from the area, who were busy with cultivation during the rainy season. Following a short investigation, three cases of patients were confirmed to be cercarial infections by skin biopsy (Bureau of Epidemiology, Department of Disease Control, Ministry of Public Health, Thailand).
“The study of intermediate host and definitive host in the outbreak area are important for the control program of snail-borne disease,” the researchers argue in their research paper, which was published in the open-access scientific journal Evolutionary Systematics.
Having studied six snail species from the area, they found out that two were infected, each with three different species of flatworms. The cercarial dermatitis outbreak was due to ruminant parasites, such as the blood fluke Schistosoma indicum, which often uses domestic animals as its host.
“Ruminant-infecting trematodes, namely, S. indicum and S. spindale, cause a hepato-intestinal schistosomiasis resulting in reduced milk yield,” the authors explain. “This occurrence of S. indicum and S. spindale implies the spread of cattle blood fluke cercariae in aquatic environments.”
“Additionally, these species of the S. indicum group primarily cause cercarial dermatitis in humans, which has become an important public health issue for people living in endemic regions.”
“In South India and Southeast Asia, where S. indicum and S. spindale have been reported to be widespread, they caused major pathology and mortality to livestock, leading to welfare and socio-economic issues, predominantly among poor subsistence farmers and their families.”
Some of the other worm species they found parasitized the intestines of fish, mammals, or birds, while others caused anemia and even death in ruminant animals.
“The results of this study will provide insights into the parasite species that cause cercarial dermatitis and may improve our understanding of public health problems in the outbreak and agricultural vicinity areas,” the authors of the study say. “In addition, the sequence data generated here are the first S. indicum DNA sequences from Thailand, which will be useful for further genetic study of the other blood flukes in this region.”
Krailas D, Namchote S, Komsuwan J, Wongpim T, Apiraksena K, Glaubrecht M, Sonthiporn P, Sansawang C, Suwanrit S (2022) Cercarial dermatitis outbreak caused by ruminant parasite with intermediate snail host: schistosome in Chana, South Thailand. Evolutionary Systematics 6(2): 151-173. https://doi.org/10.3897/evolsyst.6.87670
The World Register of Marine Species (WoRMS) announced the
Top 10 Marine Species of 2018 just in time for
Taxonomist Appreciation Day
What could be better timing to take a look back on the most spectacular animals described as new to science throughout 2018 than 19th March, Taxonomist Appreciation Day?
For the sixth time around, biologists from across the world are all hyped-up about this special date when we celebrate the experts who put things in order by giving names, identities and belonging to what the world has thought non-existent only a moment ago. After all, no sooner is a species formally acknowledged than it can be studied, understood and protected.
Having said that, at Pensoft and ZooKeys we’re immensely proud of becoming a prime publication choice for marine taxonomists from around the globe. Amongst them are the authors of not one or two, but FIVE exceptional animal curiosities, now recognised by a selected committee and the World Register of Marine Species (WoRMS), and featured in the TOP 10 Marine Species of 2018.
The “Japan Pig” which is also a… seahorse (Hippocampus japapigu)
We fail to find the obvious reason why locals diving in the waters of Hachijo-jima Island (Japan) had already likened this dazzling seahorse to a “tiny baby pig”, when a research team collected specimens and identified them as a species new to science. Naturally, the scientists assigned it with the name japapigu, which translates to “Japan Pig” in Japanese.
One thing is for sure, though, the stunning seahorse wouldn’t demand a degree in Zoology to attract anyone’s attention, had it not been for its expertise in camouflaging itself against the colourful algae-covered rocks.
News story by Douglas Main via National Geographic.
The crab that chooses an animal ‘blanket’ over a shell (Paguropsis confusa)
Sure, who would go for a rigid shell left behind by a random gastropod – just like “ordinary” hermit crabs do – when they could reach for a light, soft and elastic “blanket” instead?
That’s exactly what the blanket-hermit crab Paguropsis confusa and its sibling species have been doing as they evolved to live in a cosy symbiosis with sea anemones. While the translucent anemone peacefully “shares” the crab’s meals and grows its zoophytes around the soft-bodied crustacean, the latter is free to easily draw them up and down – as if they were a real silky duvet – and even completely cover its head whenever it feels threatened.
The crab species name is“confuso”in reference to its morphological resemblance to the closely related species Paguropsis typica. In fact, had it not been for the similarity, what we now call Paguropsis confuso would’ve most likely been described well over a century ago.
I was previously unaware of the 'blanket hermit crab,' which gently tugs an anemone up around its body like a cozy snuggly blanket and WAIT WHAT???
Amidst ongoing talks and grim forecasts of declining coral reefs spelling demise for the world as we know it, the discovery of this endemic to Okinawa Island (Japan) flower-like octocoral comes as a stunning reminder of Nature’s supremacy.
Described as a new genus, as well as a species new to science, the octocoral was aptly named Hana hanagasa, where “Hana”translates to “flower” in Japanese, while “hanagasa” is a traditional Okinawan headpiece, crafted in the form of hibiscus and worn by female dancers at ceremonies.
The distinctly hairy-foot shrimp (Odontonia bagginsi)
Upon writing up the description of this species of Indonesian shrimp,Leiden University’s then BSc student Werner de Gier is unlikely to have thought twice before coming up with the name bagginsi, as in Frodo and Bilbo Baggins – the most famous hobbits from J. R. R.Tolkien’s The Lord of the Rings and The Hobbit.
After all, what the researcher was looking at was a creature tiny enough to call another marine invertebrate – a tunicate – its snug home. Also, it had extremely hairy feet, a feature that would require for the identification key for all members of the species group to be updated.
Hobbit Shrimp (Odontonia bagginsi)
Pros: + Hot off the press https://t.co/g4PhOnhPoF + Smol, hairy, lives in a hole – totally the shrimp version of Hobbits + Did not actually steal a ring
Con: – Refuses to leave its hole to visit nearby volcanoes
The ‘secretive’ dogfish shark from Hawai’i (Squalus hawaiiensis)
One might think that an animal as large as a shark – especially if it’s the only shark species found in the waters of the Hawaiian Archipelago – would’ve “told” all its “secrets” by now, but that wasn’t the case with what we now refer to as the Hawaiian Spurdog.
Long mistaken for a stray population of a dogfish shark species originally from Japan, it wasn’t before US scientists deployed a range of elaborate tools used in species identification that it became apparent there was a previously unknown to science, short-ranged endemic shark trying to find shelter in Hawai’i.
Sadly, while the species is being depleted as bycatch, it has also demonstrated the lowest rate of genetic diversity known in a shark population to date.
Let us conclude with the words of ecologists and entomologist Dr Terry McGlynn, who started the Taxonomist Appreciation Day tradition in 2013:
“Even if you’re working on a single-species system, or are a theoretician, the discoveries and methods of systematists are the basis of your work,” he once told the Consortium of European Taxonomic Facilities (CETAF). “We need active work on taxonomy and systematics if our work is going to progress, and if we are to apply our findings. Without taxonomists, entire fields wouldn’t exist. We’d be working in darkness”.
To compile the lists, WoRMS first invited all their editors to nominate their favourites in the two disciplines, and then asked a small committee of taxonomists and data managers to provide their votes.
Without further ado, let’s dive into a little bit of a reminder to find out exactly why and how those particular species turned up at the top.
Harry Potter ‘hero’ crab (Harryplax severus)
To the delight of the millions of fans of the iconic fantasy franchise Harry Potter around the world, a new species of charming crab discovered in the coral reefs of the island of Guam, the Pacific Ocean, was named after not one, but two of their favourite characters – protagonist Harry Potter and the villain-turned-hero Professor Severus Snape.
Luckily for lead author and self-confessed ‘Potterhead’ Dr. Jose Christopher E. Mendoza, the crustacean was simultaneously identified as a new species and a new genus, which made it possible to have the genus name (Harryplax) ‘reserved’ for the famous fictional wizard, while the species name (severus) remains dedicated to his secretive teacher.
Furthermore, the two scientists – Dr. Jose Christopher E. Mendoza and Dr. Peter Ng, both affiliated with the National University of Singapore – used the scientific name of their rubble-inhabiting discovery to pay tribute to its initial collector – Harry Conley. About 20 years ago, the “soft-spoken ex-Marine with a steely determination and a heart of gold” collected a curious-looking crab from the waters of Guam to unknowingly hand his successors with a piece of nature’s undescribed gems.
Learn more about Harryplax severus on our blog or read the study published in our open access journal ZooKeys.
Bob Marley’s intertidal spider (Desis bobmarleyi)
It’s true – underwater spiders are for real!
Keep calm, though, they tend to be tiny and harmless to humans, so you are highly unlikely to get in contact with them by pure chance.
Scientists Drs. Barbara Baehr, Robert Raven and Danilo Harms, affiliated with Queensland Museum and the University of Hamburg, themselves, had to stay alert and wait for the low tide at the coastline of Australia’s “Sunshine State” of Queensland, in order to spot and collect the several-millimetre spider now known as the Bob Marley’s intertidal spider (or Desis bobmarleyi if you stumble upon it in the academic books).
Fans of the legendary reggae musician, the biologists were quick to link the emergence of the arachnid to a favourite song – “High Tide or Low Tide” – and its underlying message about love and friendship through all struggles of life.
“It is his (Bob Marley) music that aided a field trip to Port Douglas…” Incy wincy spider climbed under a seaside rock. In came the tide and washed over the spider as it chilled with the biologists dreaming of peace and love <3 https://t.co/U0StAeFiXq
Yes, the species in the picture is an animal living in the sea, even though Anemone is also a genus of flowering plants growing on the ground. Confused? In fact, the two have nothing to do with each other, apart from their ‘flowery’ appearance.
While researchers from the University of the Ryukyus, Kagoshima University, Japan and the Palau International Coral Reef Center were studying the sea anemones living on top of black coral colonies in the Indo-Pacific Ocean, they discovered a total of three new lovely species (allegedly, even more!), where one, Antipathozoanthus obscurus, was spectacular with its preference for hiding in the narrow reef cracks, rather than ‘perching’ proudly on corals.
Amazed by the quantity of yet to be explored biodiversity at the studied localities, including the island country of Palau, the scientists took the occasion to say Thank you to Palau’s President Tommy Remengesau for his nation’s support.
By naming one of the new species A. remengesaui, the scientists also pay tribute to the politician’s vision on nature conservation which has already placed Palau “at the forefront of marine conservation”, as noted by senior author Dr. James Reimer.
Find more about the new anemones from our blog post or check out the full study openly accessible in ZooKeys.
The ‘living fossil’ octocoral (Nanipora kamurai)
Dubbed ‘living fossil’ for having much more in common with extinct species than it has with its ‘living’ relatives, this octocoral discovered in Okinawa, Japan, comes to show that sometimes it’s staying calm and still on the (shallow reef) surface that takes you places.
Here, the extraordinary, in modern sense, octocoral species landed a spot among the ten most astounding marine species of the decade.
The ‘living fossil’ resembles the extraordinary blue corals, which are said to have been widely distributed around the globe during the Cretaceous period. Much like its ancestors, it sports a hard skeleton of calcium-carbonate, explain graduate student Yu Miyazaki and associate professor Dr James Davis Reimer, University of the Ryukyus.
Planning a trip to Okinawa? Keep an eye open, as this unusual species prefers depths of less than a meter, which is once again quite the contrary to the habitats picked by its contemporaries.
Check out our blog post on the ‘living fossil’ octocoral and find the study in our open access journal ZooKeys.
A huge invertebrate diversity is hidden on the forest floor in areas of the Araucaria moist forest, Brazil. Land flatworms constitute a numerous group among these invertebrates occurring in the Neotropical region. Flatworms are considered to be top predators within the soil ecosystem, preying on other invertebrates.
The Araucaria moist forest is part of the Brazilian Atlantic Rain Forest and is considered a hotspot of land flatworm diversity, harboring many yet undescribed species. Study recently published in the open access journal ZooKeys describes three new species from areas covered by Araucaria moist forest in South Brazil, which belong to the Neotropical genus Cratera.
Land flatworms lack a water retention mechanism and have a low tolerance to intense changes in temperature and humidity. Their low vagility leads to the existence of a high number of endemic species. Thus, they are considered good bioindicators of the degree of impact on their habitat.
The new species are named after characteristics of their color pattern and are probably endemic for the study areas. Besides differing from each other, as well as from other species of the genus, by their characteristic color pattern, they also show other distinguishing features in the reproductive system. The study provides an identification key to the species of the genus.
The work was conducted by the south Brazilian research group on triclads, led by Dr. Ana Leal-Zanchet, of the Universidade do Vale do Rio dos Sinos (UNISINOS), in southern Brazil. The study was supported by the Brazilian Research Council (CNPq).
Rossi, I, Leal-Zanchet, A. (2017) Three new species of Cratera Carbayo et al., 2013 from Araucaria forests with a key to species of the genus (Platyhelminthes, Continenticola). ZooKeys 643 (2017): 1-32. doi: 10.3897/zookeys.643.11093
The largest group of fanworm species with rigid chalky (calcareous) tubes belong to the Hydroides genus, and are easily recognised thanks to the shape of their beautifully ornate tube plugs. Hydroides is economically important as its members have the potential to cover immersed marine structures with massive nuisance settlements of chalky biofouling. The best-known example is Hydroides elegans, which settles on boat hulls so readily that colonies of it are perpetually in transit around the world, hitch-hiking to new places.
Latin names of animals mostly do not change over the decades because they are kept stable by a code book of naming rules. However, a mistake has recently been discovered regarding Hydroides. It turns out that it is a feminine genus rather than masculine, thus requiring each of the 107 Hydroides species names, described since 1768, to be re-examined so that the appropriate spelling, determined by the derivation of each name, can be used consistently by all biologists in future.
‘Detective’ work has often been required to get the details, as early biologists have been remarkably vague about the names they created and where their worms had come from. Fortunately, the Biodiversity Heritage Library has digitised many of the legacy taxonomic works required and it was possible to find out some unexpected information such as that species H. floridana actually did not come from Florida, although its name suggests it did.
Some Hydroides names have a descriptive basis that fits how the worms look, such as H. bulbosa, H. elegantula and H. longispinosa, others are named after people or places, for example, H. dafnii (after its collector, Yaacob Dafni) and H. sanctaecrucis (after Saint Croix Island). Yet, there are others, whose names are of quite tricky origin. It turns out that H. dianthus was actually named after a group of popular garden flowers, and H. euplaeana and H. stoichadon commemorate the long-forgotten names of tiny Mediterranean islands.
A few 19th century Hydroides descriptions are so bad that taxonomists have given up on using the names. However, one of these discarded names was revived last century by American biologists and was then used in often-cited research on sperm biology. Now, we can only guess what the actual species was.
Hydroides itself is a very old name, but it arose in a somewhat accidental and misleading way (in a letter to Linnaeus), because the worms have absolutely no connection to true hydroids, the well-known group of colonial animals related to corals.
The Hydroides species original descriptions are mostly accessible via the checklist because one third of the reports cited in the checklist are linked to the open access Biodiversity Heritage Library, and a large proportion are matched to an online source. While in the past one could only expect to find recorded the geolocations (the latitudes and longitudes) of worms collected during ship voyages, now the original localities of all the Hydroides are finally mapped. Further information on the taxonomy of all Hydroides, including many now regarded as synonyms, is available via links to the World Register of Marine Species Polychaeta web pages.
Read GB, ten Hove HA, Yanan Sun Y, Kupriyanova EK (2017) Hydroides Gunnerus, 1768 (Annelida, Serpulidae) is feminine: a nomenclatural checklist of updated names. ZooKeys 642: 1-52. https://doi.org/10.3897/zookeys.642.10443