Mysterious young sea stars, new research


Valvaster striatus sea stars

From the Smithsonian Tropical Research Institute in Panama, 13 October 2020:

Sea star’s ability to clone itself may empower this mystery globetrotter

October 13, 2020

Summary: The identity of wild cloning sea star larvae has been a mystery since they were first documented in the Caribbean. The most commonly collected cloning species was thought to belong to the Oreasteridae, on the basis of similarity with sequences from Oreaster reticulatus and Oreaster clavatus.

For decades, biologists have captured tiny sea star larvae in their nets that did not match the adults of any known species. A Smithsonian team recently discovered what these larvae grow up to be and how a special superpower may help them move around the world. Their results are published online in the Biological Bulletin.

“Thirty years ago, people noticed that these asteroid starfish larvae could clone themselves, and they wondered what the adult form was,” said staff scientist Rachel Collin at the Smithsonian Tropical Research Institute (STRI). “They assumed that because the larvae were in the Caribbean the adults must also be from the Caribbean.”

Scientists monitor larvae because the larvae can be more sensitive to physical conditions than the adults and larval dispersal has a large influence on the distribution of adult fishes and invertebrates. Collin’s team uses a technique called DNA barcoding to identify plankton. They determine the DNA sequence of an organism, then look for matches with a sequence from a known animal in a database.

“This mystery species was one of the most common in our samples from the Caribbean coast of Panama,” Collin said. “We knew from people’s studies that the DNA matched sequences from similar larvae across the Caribbean and it matched unidentified juvenile starfish caught in the Gulf of Mexico — but no one had found a match to any known adult organism in the Caribbean. So we decided to see if the DNA matched anything in the global ‘Barcode of Life’ data base.”

“That’s when we got a match with Valvaster striatus, a starfish that was thought to be found only in the Indo West Pacific,” Collin said. “The is the first-ever report of this species in the Atlantic Ocean. We could not have identifed it if Gustav Paulay from the University of Florida didn’t have DNA sequences from invertebrates on the other side of the world.”

But why are the larvae common in the Caribbean if adult Valvaster starfish have never been found here? Are the adult starfish hidden inside Caribbean reefs, or are the larvae arriving from the other side of the world?

V. striatus is widespread but rare in the western Pacific. The few reports from collectors and the confirmed photos on iNaturalist range from the Indian Ocean to Guam and Hawaii. These starfish live deep in the reef matrix, only coming out at night. So, it is possible that there are adults in the Caribbean that have never been seen. But the other possibility, that the ability to clone themselves may allow them to spread around the world, is also intriguing.

“It’s possible that the ability of the larvae to clone themselves is not just a clever way to stay forever young,” Collin said. “There’s a natural barrier that keeps organisms from the western Pacific and the Indian ocean from crossing the Atlantic to the Caribbean. After they make it around the tip of Africa, they are met by a cold current that presumably kills tropical species.”

“Just how cloning could help them get through the barrier is still not known, but it’s intriguing that another sea star species from the Indo West Pacific that was collected for the first time in the Caribbean in the 1980s also has cloning larvae,” Collin said.

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.’

Millipede evolution, new research


This 2016 video says about itself:

My friend Dani sent me two unidentified Millipedes. After a bit of research and investigation they turned out to be European White Legged Snake Millipedes (Tachypodoiulus niger ) so i thought i would show a size comparison to my adult female African Giant Millipede (Archispirostreptus gigas)

From PLOS:

Genomes of two millipede species shed light on their evolution, development and physiology

September 29, 2020

Millipedes, those many-legged denizens of the soil surface throughout the world, don’t always get the recognition they deserve. But a new study by Jerome Hui of Chinese University of Hong Kong and colleagues puts them in the spotlight, sequencing and analyzing complete genomes from two very different millipede species. The study, publishing on September 29th in the open-access journal PLOS Biology, provides important insights into arthropod evolution, and highlights the genetic underpinnings of unique features of millipede physiology.

Millipedes and centipedes together comprise the Myriapoda — arthropods with multi-segmented trunks and many legs. CentipedesHow centipedes walk and swim sport one pair of legs per segment, while millipedes bear two. Despite the apparent numeric implications of their names, different centipede species bear between 30 and 354 legs, and millipedes between 22 and 750. There are about 16,000 species of myriapods, including over 12,000 species of millipedes, but only two myriapod genomes have so far been characterized; a complete genome for the centipede Strigamia maritima, and a rough “draft” sequence of a millipede genome.

The authors of the new study fully sequenced the genomes of two millipede species, the orange rosary millipede Helicorthomorpha holstii, and the rusty millipede Trigoniulus corallinus, from two different orders, each distributed widely throughout the world. They also analyzed the gene transcripts (transcriptomes) at different stages of development, and the proteins (proteomes) of the toxin-producing “ozadene” glands.

The researchers found that two species have genomes of vastly different sizes — the orange rosary’s genome is 182 million base pairs (Mb), while the rusty’s is 449 Mb — which the authors showed was due mainly to the rusty millipede’s genome containing larger non-coding regions (introns) within genes and larger numbers of repetitive “junk” DNA sequences.

Homeobox genes play central roles in body plan formation and segmentation during animal development, and the authors found lineage-specific duplications of common homeobox genes in their two species, which differed as well from those found in the previously published millipede genome. None of the three, however, displayed the massive duplications seen in the homeobox genes in the centipede genome. They made further discoveries about the organization and regulation of the homeobox genes as well.

Many millipedes bear characteristic glands on each segment, called ozadene glands, which synthesize, store, and secrete a variety of toxic and noxious defensive chemicals. The authors identified multiple genes involved in production of these chemicals, including genes for synthesizing cyanide, as well as antibacterial, antifungal, and antiviral compounds, supporting the hypothesis that ozadene gland secretions protect against microbes as well as predators.

The results of this study provide new insights into evolution of the myriapods, and arthropods in general. “The genomic resources we have developed expand the known gene repertoire of myriapods and provide a genetic toolkit for further understanding of their unique adaptations and evolutionary pathways,” Hui said.

Why tarantula spiders are blue or green


This video is called Greenbottle Blue and Sazimai’s Blue Tarantula Comparison.

By Yale-NUS College in the USA:

Scientists discover why tarantulas come in vivid blues and greens

September 24, 2020

Summary: Researchers find support for new hypotheses: that tarantulas‘ vibrant blue colors may be used to communicate between potential mates, while green coloration confers the ability to conceal among foliage. Their research also suggests that tarantulas are not as color-blind as previously believed, and that these arachnids may be able to perceive the bright blue tones on their bodies.

Why are some tarantulas so vividly coloured? Scientists have puzzled over why these large, hairy spiders, active primarily during the evening and at night-time, would sport such vibrant blue and green colouration — especially as they were long thought to be unable to differentiate between colours, let alone possess true colour vision.

In a recent study, researchers from Yale-NUS College and Carnegie Mellon University (CMU) find support for new hypotheses: that these vibrant blue colours may be used to communicate between potential mates, while green colouration confers the ability to conceal among foliage. Their research also suggests that tarantulas are not as colour-blind as previously believed, and that these arachnids may be able to perceive the bright blue tones on their bodies. The study was published in Proceedings of the Royal Society B on 23 September, and is featured on the front cover of the current (30 September 2020) issue.

The research was jointly led by Dr Saoirse Foley from CMU, and Dr Vinod Kumar Saranathan, in collaboration with Dr William Piel, both from the Division of Science at Yale-NUS College. To understand the evolutionary basis of tarantula colouration, they surveyed the bodily expression of various opsins (light-sensitive proteins usually found in animal eyes) in tarantulas. They found, contrary to current assumptions, that most tarantulas have nearly an entire complement of opsins that are normally expressed in day-active spiders with good colour vision, such as the Peacock Spider.

These findings suggest that tarantulas, long thought to be colour-blind, can perceive the bright blue colours of other tarantulas. Using comparative phylogenetic analyses, the team reconstructed the colours of 110 million-year-old tarantula ancestors and found that they were most likely blue. They further found that blue colouration does not correlate with the ability to urticate or stridulate — both common defence mechanisms — suggesting that it did not evolve as a means of deterring predators, but might instead be a means of attracting potential mates.

The team also found that the evolution of green colouration appears to depend on whether the species in question is arboreal (tree-dwelling), suggesting that this colour likely functions in camouflage.

“While the precise function of blueness remains unclear, our results suggest that tarantulas may be able to see these blue displays, so mate choice is a likely potential explanation. We have set an impetus for future projects to include a behavioural element to fully explore these hypotheses, and it is very exciting to consider how further studies will build upon our results,” said Dr Foley.

The team’s survey of the presence of blue and green colouration across tarantulas turned up more interesting results. They found that the blue colouration has been lost more frequently than it is gained across tarantulas. The losses are mainly in species living in the Americas and Oceania, while many of the gains are in the Old World (European, Asian, and African) species. They also found that green colouration has evolved only a few times, but never lost.

“Our finding that blueness was lost multiple times in the New World, while regained in the Old, is very intriguing. This leaves several fascinating avenues for future research, when considering how the ecological pressures in the New and the Old Worlds vary,” said Dr Saranathan. “For instance, one hypothesis would be differences in the light environments of the habitats between the New and the Old World, which can affect how these colours might be perceived, if indeed they can be, as our results suggest.”

World’s oldest, dinosaur age, animal sperm discovery


This 17 September 2020 video says about itself:

100 Million-Year-Old Sperm Is The Oldest Ever Found. And It’s Giant

The oldest known sperm in the world has been discovered, locked in a piece of amber that solidified when behemoths like Spinosaurus dominated the Earth.

From Queen Mary University of London in England:

World’s oldest animal sperm found in tiny crustaceans trapped in Myanmar amber

September 16, 2020

An international collaboration between researchers at Queen Mary University of London and the Chinese Academy of Science in Nanjing has led to the discovery of world’s oldest animal sperm inside a tiny crustacean trapped in amber around 100 million years ago in Myanmar.

The research team, led by Dr He Wang of the Chinese Academy of Science in Nanjing, found the sperm in a new species of crustacean they named Myanmarcypris hui. They predict that the animals had sex just before their entrapment in the piece of amber (tree resin), which formed in the Cretaceous period.

Fossilised sperm are exceptionally rare; previously the oldest known examples were only 17 million years old. Myanmarcypris hui is an ostracod, a kind of crustacean that has existed for 500 million years and lives in all kinds of aquatic environments from deep oceans to lakes and rivers. Their fossil shells are common and abundant but finding specimens preserved in ancient amber with their appendages and internal organs intact provides a rare and exciting opportunity to learn more about their evolution.

Professor Dave Horne, Professor of Micropalaeontology at Queen Mary University of London said: “Analyses of fossil ostracod shells are hugely informative about past environments and climates, as well as shedding light on evolutionary puzzles, but exceptional occurrences of fossilised soft parts like this result in remarkable advances in our understanding.”

During the Cretaceous period in what is now Myanmar, the ostracods were probably living in a coastal lagoon fringed by trees where they became trapped in a blob of tree resin. The Kachin amber of Myanmar has previously yielded outstanding finds including frogs, snakes and a feathered dinosaur tail. Bo Wang, also of the Chinese Academy of Science in Nanjing added: “Hundreds of new species have been described in the past five years, and many of them have made evolutionary biologists re-consider long-standing hypotheses on how certain lineages developed and how ecological relationships evolved.”

The study, published in Royal Society Proceedings B, also has implications for understanding the evolutionary history of an unusual mode of sexual reproduction involving “giant sperm.”

The new ostracod finds may be extremely small but in one sense they are giants. Males of most animals (including humans) typically produce tens of millions of really small sperm in very large quantities, but there are exceptions. Some tiny fruit flies (insects) and ostracods (crustaceans) are famous for investing in quality rather than quantity: relatively small numbers of “giant” sperm that are many times longer than the animal itself, a by-product of evolutionary competition for reproductive success. The new discovery is not only by far the oldest example of fossil sperm ever found but also shows that these ostracods had already evolved giant sperm, and specially-adapted organs to transfer them from male to female, 100 million years ago.

Each ostracod is less than a millimetre long. Using X-ray microscopy the team made computer-aided 3-D reconstructions of the ostracods embedded in the amber, revealing incredible detail. “The results were amazing — not only did we find their tiny appendages to be preserved inside their shells, we could also see their reproductive organs,” added He Wang. “But when we identified the sperm inside the female, and knowing the age of the amber, it was one of those special Eureka-moments in a researcher’s life.”

Wang’s team found adult males and females but it was a female specimen that contained the sperm, indicating that it must have had sex shortly before becoming trapped in the amber. The reconstructions also revealed the distinctive muscular sperm pumps and penises (two of each) that male ostracods use to inseminate the females, who store them in bag-like receptacles until eggs are ready to be fertilised.

Such extensive adaptation raises the question of whether reproduction with giant sperms can be an evolutionarily-stable character. “To show that using giant sperms in reproduction is not an extinction-doomed extravagance of evolution, but a serious long-term advantage for the survival of a species, we need to know when they first appeared” says co-author Dr Renate Matzke-Karasz of Ludwig-Maximilians-University in Munich.

This new evidence of the persistence of reproduction with giant sperm for a hundred million years shows it to be a highly successful reproductive strategy that evolved only once in this group — quite impressive for a trait that demands such a substantial investment from both males and females, especially when you consider that many ostracods can reproduce asexually, without needing males at all. “Sexual reproduction with giant sperm must be very advantageous” says Matzke-Karasz.

New spider species discovered in Colombia


This 21 September 2020 video is called New species of spider discovered – Ocrepeira klamt.

From the Universität Bayreuth in Germany:

A new species of spider

September 16, 2020

During a research stay in the highlands of Colombia conducted as part of her doctorate, Charlotte Hopfe, PhD student under the supervision of Prof. Dr. Thomas Scheibel at the Biomaterials research group at the University of Bayreuth, has discovered and zoologically described a new species of spider. The previously unknown arachnids are native to the central cordillera, not far from the Pacific coast, at an altitude of over 3,500 meters above sea-level. In the magazine PLOS ONE, the scientist from Bayreuth presents the spider she has called Ocrepeira klamt.

“I chose the zoological name Ocrepeira klamt in honour of Ulrike Klamt, my German teacher at high school. The enthusiasm with which she pursues her profession and the interest she shows in her students and in literature are an inspiration to me,” says Charlotte Hopfe.

The cordillera in Colombia is famous for its unusually large variety of species. The habitats of these species are distributed at altitudes with very different climatic conditions, vegetation, and ecosystems. The Bayreuth researcher has collected and zoologically determined specimens of more than 100 species of spider in these habitats. In doing so, she was mainly in a region that has only been accessible to researchers since the end of civil war in Colombia in 2016. She discovered the new spider, which differs from related species in the striking structure of its reproductive organs, at altitudes of over 3,500 meters above sea-level. In the identification of this and many other spider specimens, Hopfe received valuable support from researchers at Universidad del Valle in Cali, Colombia, with which the University of Bayreuth has a research cooperation. Colombia has been identified as a priority country in the internationalization strategy of the University of Bayreuth, which is why it maintains close connections with several Colombian universities.

The study of spiders from regions of such various huge climatic and ecological variety may also offer a chance to find answers to two as yet unexplored questions. It is not yet known whether temperatures, precipitation, or other climatic factors influence the evolution of spiders, or the properties of their silk. For example, is the proportion of species with extremely elastic silk in the lowland rainforest higher than in the semi-desert? And it is also still unclear whether the properties of the silk produced by a species of spider are modified by climatic factors. Would a spider living in the high mountains, such as Ocrepeira klamt, produce the same silk if it were native to a much lower region of the cordillera? The answer to these questions could provide important clues as to the conditions under which unusual spider silks develop.

Along similar lines, it would also be interesting to explore whether there are spider silk proteins which, due to their properties, are even more suitable for certain applications in biomedicine and biotechnology than silk proteins currently known. “The greater the variety of spider silks whose structures and properties we know, the greater the potential to optimize existing biomaterials and to develop new types of biomaterials on the basis of silk proteins,” Hopfe explains.

Charlotte Hopfe’s research was funded by the German Academic Exchange Service and the German Academic Scholarship Foundation.

Arctic plants and insects


This 2014 video from Canada says about itself:

Jennifer Doubt, botanist and curator at the Canadian Museum of Nature, talks about discovering Arctic plants.

She explores terrain in Iqaluit, Nunavut, and Greenland during a Students on Ice Arctic expedition.

Expedition Arctic is an educational web site for youth. It was created by the Canadian Museum of Nature, Students on Ice and Habitat Seven, in collaboration with the Virtual Museum of Canada.

Insect pollination is as important to Arctic plants as it is to plants further south. When flowers abound, the plants have to compete for pollinators. Researchers at the University of Helsinki reveal that higher temperatures cause the flowering periods of different plant species to pile up in time. As a consequence, climate change may affect the competitive relationships of plants. The most attractive plant species steal the majority of pollinators, making other plants flowering at the same time suffer from poorer pollination: here.

Through a unique research collaboration, researchers at the University of Helsinki have exposed major changes taking place in the insect communities of the Arctic. Their study reveals how climate change is affecting small but important predators of other insects, i.e. parasitoids: here.

Extinct sea scorpions could breathe on land


This April 2019 video says about itself:

Sea scorpions thrived for 200 million years, coming in a wide variety of shapes and sizes. Over time, they developed a number of adaptations–from crushing claws to flattened tails for swimming. And some of them adapted by getting so big that they still hold the record as the largest arthropods of all time.

From West Virginia University in the USA:

Coming up for air: Extinct sea scorpions could breathe out of water, fossil detective unveils

September 10, 2020

Summary: Through computed tomography (CT) imaging, geologists found evidence of air breathing in a 340 million-year-old sea scorpion, or eurypterid.

Scientists have long debated the respiratory workings of sea scorpions, but a new discovery by a West Virginia University geologist concludes that these largely aquatic extinct arthropods breathed air on land.

James Lamsdell dug into the curious case of a 340 million-year-old sea scorpion, or eurypterid, originally from France that had been preserved at a Glasgow, Scotland museum for the last 30 years.

An assistant professor of geology in the Eberly College of Arts and Sciences, Lamsdell had read about the “strange specimen” 25 years ago while conducting his doctoral studies. Existing research suggested it would occasionally go on land.

Yet nothing was known on whether it could breathe air. The closest living relative to the eurypterid is the horseshoe crab, which lays eggs on land but is unable to breathe above water.

These details puzzled Lamsdell through the years until he reached out to a colleague, Victoria McCoy at the University of Wisconsin-Milwaukee, and asked, “Do you have access to a CT scanner?”

“We wondered if we could apply new technology to look further into what was preserved of this specimen,” said Lamsdell, who heads a paleobiology lab at WVU. “I like the science and detective work that goes into research. And this was a cold case where we knew there was potential evidence.”

Through computed tomography (CT) imaging, Lamsdell and his team found that evidence, which is published in Current Biology.

Researchers managed to study the respiratory organs of the three-dimensional eurypterid, leading to two findings that stood out to Lamsdell. First, he noticed that each gill on the sea scorpion was composed of a series of plates. But the back contained fewer plates than the front, prompting researchers to question how it could even breathe.

Then they zeroed in on pillars connecting the different plates of the gill, which are seen in modern scorpions and spiders, Lamsdell said. These pillars, or small beams of tissue, are called trabeculae.

“That props the gills apart so they don’t collapse when out of water,” Lamsdell explained. “It’s something that modern arachnids still have. Finding that was the final indication.

“The reason we think they were coming onto land was to move between pools of water. They could also lay eggs in more sheltered, safer environments and migrate back into the open water.”

The discovery of air-breathing structures in the eurypterids indicate that terrestrial characteristics occurred in the arachnid stem lineage, the researchers wrote, suggesting that the ancestor of arachnids were semi-terrestrial.

In addition to Lamsdell and McCoy, co-authors include Opal Perron-Feller of Oberlin College and Melanie Hopkins of the American Museum of Natural History.

Now that Lamsdell has cracked the case living in the back of his head for 20-plus years, he believes there’s more to unearth from the fossil. He noted that the sea scorpion’s back legs expand into a paddle shape, which he suspects would have been used to swim. The bases of their legs also had spikes that ground up food for them that they maneuvered into their mouths, Lamsdell added.

“One of the things that would be really cool to do is to flesh out this model and try to reconstruct exactly how the legs could move and how they were positioned,” Lamsdell said, “like reconstructing the fossil as a living animal.”