Tag: biogeography

New species of stiletto snake capable of sideways strikes discovered in West Africa

*The first discovered specimen of the newly described species (Atractaspis branchi or Branch’s Stiletto Snake) in its natural habitat. Photo by Mark-Oliver Roedel.*

Following a series of recent surveys in north-western Liberia and south-eastern Guinea, an international team of researchers found three stiletto snakes which were later identified as a species previously unknown to science.

The discovery, published in the open-access journal Zoosystematics and Evolution by the team of Dr Mark-Oliver Roedel from the Natural History Museum, Berlin, provides further evidence for the status of the western part of the Upper Guinea forest zone as a center of rich and endemic biodiversity.

Curiously, stiletto snakes have unusual skulls and venom delivery system, allowing them to attack and stab sideways with a fang sticking out of the corner of their mouths. While most of these burrowing snakes are not venomous enough to kill a human – even though some are able to inflict serious tissue necrosis – this behaviour makes them impossible to handle using the standard approach of holding them with fingers behind the head. In fact, they can even stab with their mouths closed.

The new species, called Atractaspis branchi or Branch’s Stiletto Snake, was named to honor to the recently deceased South African herpetologist Prof. William Roy (Bill) Branch, a world leading expert on African reptiles.

*The first specimen was found at night, moving along the steep slope on the left bank of the small creek (Liberia). Photo by Mark-Oliver Roedel.*

The new species lives in primary rainforest and rainforest edges in the western part of the Upper Guinea forests. Branch’s Stiletto Snake is most likely endemic to this area, a threatened biogeographic region already known for its unique and diverse fauna.

The first specimen of the new species was collected at night from a steep bank of a small rocky creek in a lowland evergreen rainforest in Liberia. Upon picking it up, the snake tried to hide its head under body loops, bending it at an almost right angle, so that its fangs were partly visible on the sides. Then, it repeatedly stroke. It is also reported to have jumped distances almost as long as its entire body. The other two specimens used for the description of the species were collected from banana, manioc and coffee plantations in south-eastern Guinea, about 27 km apart.

“The discovery of a new and presumably endemic species of fossorial snake from the western Upper Guinea forests thus is not very surprising,” conclude the researchers. “However, further surveys are needed to resolve the range of the new snake species, and to gather more information about its ecological needs and biological properties.”

*Close up of the Branch’s Stiletto Snake in its natural habitat. Photo by Mark-Oliver Roedel.*

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Original source:

Rödel M, Kucharzewski C, Mahlow K, Chirio L, Pauwels OSG, Carlino P, Sambolah G, Glos J (2019) A new stiletto snake (Lamprophiidae, Atractaspidinae, Atractaspis) from Liberia and Guinea, West Africa. Zoosystematics and Evolution 95(1): 107-123. https://doi.org/10.3897/zse.95.31488

Star Wars and Asterix characters amongst 103 beetles new to science from Sulawesi, Indonesia

*From left to right: Trigonopterus asterix, T. obelix and T. idefix, three newly described species from Sulawesi (Indonesia). Image by Alexander Riedel.*

The Indonesian island of Sulawesi has been long known for its enigmatic fauna, including the deer-pig (babirusa) and the midget buffalo. However, small insects inhabiting the tropical forests have remained largely unexplored.

Such is the case for the tiny weevils of the genus Trigonopterus of which only a single species had been known from the island since 1885. Nevertheless, a recent study conducted by a team of German and Indonesian scientists resulted in the discovery of a total of 103 new to science species, all identified as Trigonopterus. The beetles are described in the open-access journal ZooKeys.

“We had found hundreds of species on the neighboring islands of New Guinea, Borneo and Java – why should Sulawesi with its lush habitats remain an empty space?” asked entomologist and lead author of the study Dr Alexander Riedel, Natural History Museum Karlsruhe (Germany).

In fact, Riedel knew better. Back in 1990, during a survey of the fauna living on rainforest foliage in Central Sulawesi, he encountered the first specimens that would become the subject of the present study. Over the next years, a series of additional fieldwork, carried out in collaboration with the Indonesian Institute of Sciences (LIPI), managed to successfully complete the picture.

“Our survey is not yet complete and possibly we have just scratched the surface. Sulawesi is geologically complex and many areas have never been searched for these small beetles,” said Raden Pramesa Narakusumo, curator of beetles at the Museum Zoologicum Bogoriense (MZB), Indonesian Research Center for Biology.

*Dense mountain forest of Central Sulawesi, where some of the new species have been found. Image by Alexander Riedel.*

Why have all these beetles remained overlooked for so long?

Unlike the all-time favourite stag beetles or jewel beetles, tiny beetles that measure no more than 2-3 millimeters seem to have been attracting little interest from entomologists. Their superficial resemblance does not help identification either.

In fact, the modern taxonomic approach of DNA sequencing seems to be the only efficient method to diagnose these beetles. However, the capacity for this kind of work in Indonesia is very limited. While substantial evidence points to thousands of undescribed species roaming the forests in the region, there is only one full-time position for a beetle researcher at the only Indonesian Zoological Museum near Jakarta. Therefore, international collaboration is crucial.

*103 newly discovered species of the genus Trigonopterus from Sulawesi. Image by Alexander Riedel.*

103 beetle names

Coming up with as many as 103 novel names for the newly described species was not a particularly easy task for the researchers either. While some of the weevils were best associated with their localities or characteristic morphology, others received quite curious names.

A small greenish and forest-dwelling species was aptly named after the Star Wars character Yoda, while a group of three species were named after Asterix, Obelix and Idefix – the main characters in the French comics series The Adventures of Asterix. Naturally, Trigonopterus obelix is larger and more roundish than his two ‘friends’.

Other curious names include T. artemis and T. satyrus, named after two Greek mythological characters: Artemis, the goddess of hunting and nature and Satyr, a male nature spirit inhabiting remote localities.

Additionally, the names of four of the newly described beetles pay tribute to renowned biologists, including Charles Darwin (father of the Theory of Evolution), Paul D. N. Hebert (implementer of DNA barcoding as a tool in species identification) and Francis H. C. Crick and James D. Watson (discoverers of the structure of DNA).

Six-legged déjà vu

Back in 2016, in another weevil discovery, Dr Alexander Riedel and colleagues described four new species from New Britain (Papua New Guinea), which were also placed in the genus Trigonopterus. Similarly, no weevils of the group had been known from the island prior to that study. Interestingly, one of the novel species was given the name of Star Wars’ Chewbacca in reference to the insect’s characteristically dense scales reminiscent of Chewie’s hairiness. Again, T. chewbacca and its three relatives were described in ZooKeys.

*The flightless beetle species Trigonopterus chewbacca, described as new to science in 2016. Image by Alexander Riedel.*

On the origin of Trigonopterus weevils

Sulawesi is at the heart of Wallacea, a biogeographic transition zone between the Australian and Asian regions. The researchers assume that Trigonopterus weevils originated in Australia and New Guinea and later reached Sulawesi. In fact, it was found that only a few populations would one day diversify into more than a hundred species. A more detailed study on the rapid evolution of Sulawesi Trigonopterus is currently in preparation.

Future research

To help future taxonomists in their work, in addition to their monograph paper in ZooKeys, the authors have uploaded high-resolution photographs of each species along with a short scientific description to the website Species ID.

“This provides a face to the species name, and this is an important prerequisite for future studies on their evolution,” explained the researchers.

“Studies investigating such evolutionary processes depend on names and clear diagnoses of the species. These are now available, at least for the fauna of Sulawesi.”

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Original Source:

Riedel A, Narakusumo RP (2019) One hundred and three new species of Trigonopterus weevils from Sulawesi. ZooKeys 828: 1-153. https://doi.org/10.3897/zookeys.828.32200

New tarantula species from Angola distinct with a one-of-a-kind ‘horn’ on its back

A new to science species of tarantula with a peculiar horn-like protuberance sticking out of its back was recently identified from Angola, a largely underexplored country located at the intersection of several Afrotropical ecoregions.

Collected as part of the National Geographic Okavango Wilderness Project, which aims to uncover the undersampled biodiversity in the entire Okavango catchment of Angola, Namibia and Botswana, thereby paving the way for sustainable conservation in the area, the new arachnid is described in a paper published in the open-access journal African Invertebrates by the team of Drs John Midgley and Ian Engelbrecht.

Although the new spider (Ceratogyrus attonitifer sp.n.) belongs to a group known as horned baboon spiders, the peculiar protuberance is not present in all of these species. Moreover, in the other species – where it is – the structure is completely sclerotised, whereas the Angolan specimens demonstrate a soft and characteristically longer ‘horn’. The function of the curious structure remains unknown.

The new tarantula’s extraordinary morphology has also prompted its species name: C. attonitifer, which is derived from the Latin root attonit– (“astonishment” or “fascination”), and the suffix –fer (“bearer of” or “carrier”). It refers to the astonishment of the authors upon the discovery of the remarkable species.

“No other spider in the world possesses a similar foveal protuberance,” comment the authors of the paper.

*Individual of the newly described species in defensive posture in its natural habitat. Photo by Kostadine Luchansky.*

During a series of surveys between 2015 and 2016, the researchers collected several female specimens from the miombo forests of central Angola. To find them, the team would normally spend the day locating burrows, often hidden among grass tufts, but sometimes found in open sand, and excavate specimens during the night. Interestingly, whenever the researchers placed an object in the burrow, the spiders were quick and eager to attack it.

The indigenous people in the region provided additional information about the biology and lifestyle of the baboon spider. While undescribed and unknown to the experts until very recently, the arachnid has long been going by the name “chandachuly” among the local tribes. Thanks to their reports, information about the animal’s behaviour could also be noted. The tarantula tends to prey on insects and the females can be seen enlarging already existing burrows rather than digging their own. Also, the venom of the newly described species is said to not be dangerous to humans, even though there have been some fatalities caused by infected bites gone untreated due to poor medical access.

In conclusion, the researchers note that the discovery of the novel baboon spider from Angola does not only extend substantially the known distributional range of the genus, but can also serve as further evidence of the hugely unreported endemic fauna of the country:

“The general paucity of biodiversity data for Angola is clearly illustrated by this example with theraphosid spiders, highlighting the importance of collecting specimens in biodiversity frontiers.”

Apart from the described species, the survey produced specimens of two other potentially new to science species and range expansions for other genera. However, the available material is so far insufficient to formally diagnose and describe them.

*The newly described baboon spider species (Ceratogyrus attonitifer), showing the peculiar soft and elongated horn-like protuberance sticking out of its back. Photo by Dr Ian Enelbrecht.*

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Original source:

Midgley JM, Engelbrecht I (2019) New collection records for Theraphosidae (Araneae, Mygalomorphae) in Angola, with the description of a remarkable new species of Ceratogyrus. African Invertebrates 60(1): 1-13. https://doi.org/10.3897/afrinvertebr.60.32141

The Widow Next Door: Where is the globally invasive Noble False Widow settling next?

*Noble false widow spider (Steatoda nobilis) at a public bus stop in the seaside resort of Lyme Regis, southern England. Photo by Rainer Breitling.*

Spiders are one of the most successful groups of ‘invaders’ on the planet. Out of over 47,000 species of spiders known today, there are some that tend to follow humans across the globe and settle in habitats far away from their native homelands. A particularly notorious example is the species Steatoda nobilis, the Noble False Widow spider.

Originating from Madeira (Portugal) and the Canary Islands (Spain), the Noble False Widow has been rapidly spreading around the globe over the last few decades. While the species is already well established in Western Europe and large parts of the Mediterranean area, it has recently spread into California, South America and Central Europe. Meanwhile, its populations in England, where the spider used to be restricted to the very southern parts of the country, are now seen to experience a sudden expansion northwards.

As its name suggests, this is a relatively large species that resembles the well-known Black Widow and can inflict a painful – yet mostly harmless to humans – bite. Naturally, its ‘arrival’ causes widespread concerns and public disruptions. Specifically, the Noble False Widow poses a threat to native faunas, since it can prey on nearly every smaller animal thanks to its potent venom and sturdy webs.

Recently, experts and non-professional citizen scientists joined forces to reconstruct the invasion path of the Noble False Widow in Europe and the Americas, so that they could identify patterns and predict which regions are likely to be the next colonised by the spider.

By combining data from museum collections and the Spider and Harvestman Recording Scheme of the British Arachnological Society with published literature and their own observations from England, Germany, France and Ecuador, the researchers provided an unprecedented detailed view of the expansion of the Noble False Widow. The study, conducted by Tobias Bauer (State Museum of Natural History Karlsruhe), Stephan Feldmeier (Trier University), Henrik Krehenwinkel (Trier University and University of California Berkeley), Rainer Breitling (University of Manchester) and citizen scientists Carsten Wieczorrek and Nils Reiser, is published in the open-access journal Neobiota.

While it had largely been assumed that the Noble False Widow turned up in Europe along with bananas traded from the Canary Islands, a new look at the data revealed that the spiders have most likely been transported via imports of ornamental plants. Further, rather than the result of climate change, the establishment of the species across new, large territories is rather linked to the fact that these habitats all share similar conditions to the spider’s native localities.

“Similar suitable False Widow habitats occur in quite specific regions all around the globe,” explain the researchers. “Most importantly, South Africa, some areas in southern Australia, and a large part of New Zealand turn out to be highly likely targets for future invasions, unless appropriate import control measures are implemented.”

*Global prediction of suitable regions for the Noble False Widow (Steatoda nobilis). Image by Stephan Feldmeier & Tobias Bauer.*

In conclusion, the authors call for enhanced monitoring of the Noble False Widow as well as its still little known ecological impact on the environment in newly colonised areas. They also urge scientists in the predicted potential invasion target regions to search for specimens, especially in coastal cities.

Original source:

Bauer T, Feldmeier S, Krehenwinkel H, Wieczorrek C, Reiser N, Breitling R (2019) Steatoda nobilis, a false widow on the rise: a synthesis of past and current distribution trends. NeoBiota 42: 19-43. https://doi.org/10.3897/neobiota.42.31582

Scientists discover over 450 fossilised millipedes in 100-million-year-old amber

Since the success of the Jurassic Park film series, it is widely known that insects from the Age of the Dinosaurs can be found exceptionally well preserved in amber, which is in fact fossilised tree resin.

Especially diverse is the animal fauna preserved in Cretaceous amber from Myanmar (Burma). Over the last few years, the almost 100-million-year-old amber has revealed some spectacular discoveries, including dinosaur feathers, a complete dinosaur tail, unknown groups of spiders and several long extinct groups of insects.

However, as few as three millipede species, preserved in Burmese amber, had been found prior to the study of Thomas Wesener and his PhD student Leif Moritz at the Zoological Research Museum Alexander Koenig – Leibniz Institute for Animal Biodiversity (ZFMK). Their research was recently published in the open-access journal Check List.

One of the newly discovered fossilised millipedes. Photo by Dr Thomas Wesener.

Having identified over 450 millipedes preserved in the Burmese amber, the scientists confirmed species representing as many as 13 out of the 16 main orders walking the Earth today. The oldest known fossils for half of these orders were found within the studied amber.

The researchers conducted their analysis with the help of micro-computed tomography (micro-CT). This scanning technology uses omni-directional X-rays to create a 3D image of the specimen, which can then be virtually removed from the amber and digitally examined.

The studied amber is mostly borrowed from private collections, including the largest European one, held by Patrick Müller from Käshofen. There are thought to be many additional, scientifically important specimens, perhaps even thousands of them, currently inaccessible in private collections in China.

Over the next few years, the newly discovered specimens will be carefully described and compared to extant species in order to identify what morphological changes have occurred in the last 100 million years and pinpoint the speciation events in the millipede Tree of Life. As a result, science will be finally looking at solving long-standing mysteries, such as whether the local millipede diversity in the southern Alps of Italy or on the island of Madagascar is the result of evolutionary processes which have taken place one, ten or more than 100-million years ago.

According to the scientists, most of the Cretaceous millipedes found in the amber do not differ significantly from the species found in Southeast Asia nowadays, which is an indication of the old age of the extant millipede lineages.

On the other hand, the diversity of the different orders seems to have changed drastically. For example, during the Age of the Dinosaurs, the group Colobognatha – millipedes characterised by their unusual elongated heads which have evolved to suck in liquid food – used to be very common. In contrast, with over 12,000 millipede species living today, there are only 500 colobognaths.

Another curious finding was the discovery of freshly hatched, eight-legged juveniles, which indicated that the animals lived and reproduced in the resin-producing trees.

“Even before the arachnids and insects, and far ahead of the first vertebrates, the leaf litter-eating millipedes were the first animals to leave their mark on land more than 400-million-years ago,” explain the scientists. “These early millipedes differed quite strongly from the ones living today – they would often be much larger and many had very large eyes.”

The larger species in the genus Arthropleura, for example, would grow up to 2 m (6.5 ft) long and 50-80 cm (2-3 ft) wide – the largest arthropods to have ever crawled on Earth. Why these giants became extinct and those other orders survived remains unknown, partly because only a handful of usually badly preserved fossils from the whole Mesozoic era (252-66-million years ago) has been retrieved. Similarly, although it had long been suspected that the 16 modern millipede orders must be very old, a fossil record to support this assumption was missing.

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Original source:

Wesener T, Moritz L (2018) Checklist of the Myriapoda in Cretaceous Burmese amber and a correction of the Myriapoda identified by Zhang (2017). Check List 14(6): 1131-1140. https://doi.org/10.15560/14.6.1131

Austrian-Danish research team discover as many as 22 new moth species from across Europe

The last time so many previously unknown moths have been discovered at once in the best-studied continent was in 1887

*One of the newly discovered moths, Megacraspedus faunierensis, in its natural habitat in the Alps.*

Following a long-year study of the family of twirler moths, an Austrian-Danish research team discovered a startling total of 44 new species, including as many as 22 species inhabiting various regions throughout Europe.

Given that the Old Continent is the most thoroughly researched one, their findings, published in the open access journal ZooKeys, pose fundamental questions about our knowledge of biodiversity. Such wealth of new to science European moths has not been published within a single research article since 1887.

“The scale of newly discovered moths in one of the Earth’s most studied regions is both sensational and completely unexpected,” say authors Dr Peter Huemer, Tyrolean State Museum, and Ole Karsholt of the University of Copenhagen‘s Zoological Museum. To them, the new species come as proof that, “despite dramatic declines in many insect populations, our fundamental investigations into species diversity are still far from complete”.

The challenge of taxonomy

*Type locality of the new moth species Megacraspedus faunierensis, Cottian Alps, Italy.*

For the authors, it all began when they spotted what seemed like an unclassifiable species of twirler moth in the South Tyrolean Alps. In order to confirm it as a new species, the team conducted a 5-year study into the type specimens of all related species spread across the museum collections of Paris, London, Budapest and many in between.

To confirm the status of all new species, the scientists did not only look for characteristic colouration, markings and anatomical features, but also used the latest DNA methods to create unique genetic fingerprints for most of the species in the form of DNA barcodes.

What’s in a name?

A particular challenge for the researchers was to choose as many as 44 names for the new species. Eventually, they named one of the species after the daughter of one of the authors, others – after colleagues and many others – after the regions associated with the particular species. Megacraspedus teriolensis, for example, is translated to “Tyrolean twirler moth”.

Amongst the others, there is one which the scientists named Megacraspedus feminensisbecause they could only find the female, while another – Megacraspedus pacificus, discovered in Afghanistan – was dubbed “an ambassador of peace”.

Mysterious large twirler moths

All new moths belong to the genus of the large twirler moths (Megacraspedus) placed in the family of twirler moths (Gelechiidae), where the common name refers to their protruding modified mouthparts (labial palps).

The genus of the large twirler moths presents an especially interesting group because of their relatively short wings, where their wingspan ranges between 8 and 26 millimetres and the females are often flightless. While it remains unknown why exactly their wings are so reduced, the scientists assume that it is most likely an adaptation to the turbulent winds at their high-elevation habitats, since the species prefer mountain areas at up to 3,000 metres above sea level.

Out of the 85 documented species, however, both sexes are known in only 35 cases.

The scientists suspect that many of the flightless females are hard to spot on the ground. Similarly, caterpillars of only three species have been observed to date.

While one of the few things we currently know about the large twirler moths is that all species live on different grasses, Huemer and Karsholt believe that it is of urgent importance to conduct further research into the biology of these insects, in order to identify their conservation status and take adequate measures towards their preservation.

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Original source:

Huemer P, Karsholt O (2018) Revision of the genus Megacraspedus Zeller, 1839, a challenging taxonomic tightrope of species delimitation (Lepidoptera, Gelechiidae). ZooKeys 800: 1-278. https://doi.org/10.3897/zookeys.800.26292

The first cave-dwelling centipede from southern China

Chinese scientists recorded the first cave-dwelling centipede known so far from southern China. To the amazement of the team, the specimens collected during a survey in the Gaofeng village, Guizhou Province, did not only represent a species that had been successfully hiding away from biologists in the subterranean darkness, but it also turned out to be the very first amongst the order of stone centipedes to be discovered underground in the country.

Found by the team of Qing Li, Xuan Guo and Dr Hui-ming Chen of the Guizhou Institute of Biology, and Su-jian Pei and Dr Hui-qin Ma of Hengshui University, the new cavedweller is described under the name of Australobius tracheoperspicuus in the open-access journal ZooKeys.

The new centipede is quite tiny, measuring less than 20 mm in total body length. It is also characterised with pale yellow-brownish colour and antennae comprised of 26 segments each. Similar to other cave-dwelling organisms which have evolved to survive away from sunlight, it has no eyes.

In their paper, the authors point out that Chinese centipedes and millipedes remain poorly known, where the statement holds particularly true for the fauna of stone centipedes: the members of the order Lithobiomorpha. As of today, there are only 80 species and subspecies of lithobiomorphs known from the country. However, none of them lives underground.

In addition, the study provides an identification key for all six species of the genus Australobius recorded in China.

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Original source:

Li Q, Pei S-j, Guo X, Ma H-q, Chen H-m (2018) Australobius tracheoperspicuus sp. n., the first subterranean species of centipede from southern China (Lithobiomorpha, Lithobiidae). ZooKeys 795: 83-91. https://doi.org/10.3897/zookeys.795.28036

Newly discovered moth named Icarus sports a flame-shaped mark and prefers high elevations

The paper describing the new species is part of a special issue dedicated to macro moths of the New World published in the open-access journal ZooKeys

Newly-recognized species of owlet moth recently discovered to inhabit high-elevation mountains in western North America was named after the Greek mythological character Icarus. From now on, scientists will be referring to the new insect as Admetovis icarus.

In their paper, Dr Lars Crabo, Washington State University, USA, and Dr Christian Schmidt, Agriculture and Agri-Food Canada, explain that the combination of the distinct flame-shaped mark on the moth’s forewing and its high-elevation habitat were quick to remind them of Icarus, who is said to have died after flying so close to the sun that his wings made of wax and feathers caught fire.

The study is part of the seventh volume of the “Contributions to the systematics of New World macro-moths” series, where all previous volumes have also been published as special issues in ZooKeys.

Found in the town of Nederland, Colorado, the moth was collected at an elevation of 2,896 m above sea level. The species has also been recorded all the way from central Utah and central Colorado to the Selkirk Mountains of southeastern British Columbia, including a record from northeastern Oregon. It can be spotted between June and August at night.

In fact, it turns out that the moth has been collected during surveys in the past on multiple occasions, but has been misidentified with another closely related species: Admetovis oxymorus.

While the flame mark is a characteristic feature in all three species known in the genus (Admetovis), in the newly described species it is darker. When compared, the wings of the Icarus moth are also more mottled.

Despite the biology of the larvae being currently unknown, the scientists believe they are climbing cutworms and feed on woody shrubs, similarly to the species Admetovis oxymorus.

“Finding undiscovered moths is not that unusual, even though scientists have been naming insects since the eighteenth century,” says lead author Dr Lars Crabo.

“The Contributions series, edited by Don Lafontaine and Chris Schmidt, in which this discovery is published, really encourages professional and citizen scientists alike to go through the steps necessary to properly name the species that they have discovered. This series of seven volumes also includes a new check list for the United States and Canada, which has led to a re-kindling of interest in moths during the last decade.”

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Original source:

Crabo LG, Schmidt BC (2018) A revision of Admetovis Grote, with the description of a new species from western North America (Noctuidae, Noctuinae, Hadenini). In: Schmidt BC, Lafontaine JD (Eds) Contributions to the systematics of New World macro-moths VII. ZooKeys788: 167-181. https://doi.org/10.3897/zookeys.788.26480

New light on the controversial question of species abundance and population density

Inspired by the negative results in the recently published largest-scale analysis of the relation between population density and positions in geographic ranges and environmental niches, Drs Jorge Soberon and Andrew Townsend Peterson of the University of Kansas, USA, teamed up with Luis Osorio-Olvera, National University of Mexico (UNAM), and identified several issues in the methodology used, able to turn the tables in the ongoing debate. Their findings are published in the innovative open access journal Rethinking Ecology.

Both empirical work and theoretical arguments published and cited over the last several years suggest that if someone was to take the distributional range of a species – be it animal or plant – and draw lines starting at the edges of the space inwards, they would find the species’ populations densest at the intersection of those lines. However, when the team of Tad Dallas, University of Helsinki, Finland, analysed a large dataset of 118,000 populations, equating to over 1,400 species of birds, mammals, and trees, they found no such relationship.

Having analysed the analysis, the American-Mexican team concluded that despite being based on an unprecedented volume of data, the earlier study was missing out some important points.

Firstly, the largest dataset used by Tad and his team comprises observational data which had not required a certain sampling protocol or a plan. Without any standard in use, it is easy to imagine that the observations would be predominantly coming from people around and near cities, hence strongly biased.

Additionally, the scientists note that the analysis largely disregards parts of species’ geographic distributions for which there were no abundant data. As a result, the range of a species could be narrowed down significantly and its centroid – misplaced. Meanwhile, the population would appear denser on what appears to be the periphery of the area.

Similar issue is identified in the localisation of populations in the environmental space, where once again their range turned out to have been represented as significantly smaller, when compared to data available from the International Union for Conservation of Nature (IUCN) and the Global Biodiversity Information Facility (GBIF).

Further, a closer look into the supplementary materials provided revealed that the precision of the population-density data was not scalable with the climate data. As a result, it is likely that multiple abundance data falls within a single climate pixel.

In conclusion, the authors note that in order to comprehensively study the abundance of a species’ populations, one needs to take into consideration a number of factors lying beyond the scope of either of the papers, including human impact.

“We suggest that this important question remains far from settled,” they say.

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Original source:

Soberón J, Peterson TA, Osorio-Olvera L (2018) A comment on “Species are not most abundant in the centre of their geographic range or climatic niche”. Rethinking Ecology 3: 13-18. https://doi.org/10.3897/rethinkingecology.3.24827

Tiny moth from Asia spreading fast on Siberian elms in eastern North America

In 2010, moth collector James Vargo began finding numerous specimens of a hitherto unknown pygmy moth in his light traps on his property in Indiana, USA. When handed to Erik van Nieukerken, researcher at Naturalis Biodiversity Center (Leiden, the Netherlands) and specialist in pygmy moths (family Nepticulidae), the scientist failed to identify it as a previously known species.

*These are male specimens of the studied leaf mining moth Stigmella multispicata collected from Iowa, USA.*

Then, Erik found a striking similarity of the DNA barcodes with those of a larva he had recently collected on Siberian elm in Beijing’s botanical garden. At the time, the Chinese specimen could not be identified either.

In October 2015, Daniel Owen Gilrein, entomologist at Cornell Cooperative Extension of Suffolk County (New York, USA), received samples of green caterpillars seen to descend en masse from Siberian elm trees in Sagaponack, New York. He also received leafmines from the same trees.

Once they joined forces, the researchers did not take long to find out that the specimens from James Vargo and the caterpillars from New York belonged to one and the same species. The only thing left was its name.

Following further investigation, the scientists identified the moth as Stigmella multispicata – a pygmy moth described in 2014 from Primorye, Russia, by the Lithuanian specialists Agne Rociene and Jonas Stonis.

“Apparently, this meant that we were dealing with a recent invasion from East Asia into North America,” explains Erik.

Once the researchers had figured out how to identify the leafminer, they were quick to spot its existence in plenty of collections and occurrence reports from websites, such as BugGuide and iNaturalist.

With the help of Charley Eiseman, a naturalist from Massachusetts specializing in North American leafminers, the authors managed to conclude the moth’s existence in ten US states and two Canadian provinces. In most cases, the species was found on or near Siberian elm – another species transferred from Asia to North America.

Their study is published in the open access journal ZooKeys.

Despite the oldest records dating from 2010, it turned out that the species had already been well established at the time. The authors suspect that the spread has been assisted by transport of plants across nurseries.

“Even though Stigmella multispicata does not seem to be a real problem, it would be a good idea to follow its invasion over North America, and to monitor whether the species may also attack native elm species,” the researchers point out.

Interestingly, in addition to the newly identified moth, the Siberian elms in North America have been struggling with another, even more common, invasive leafminer from Asia: the weevil species Orchestes steppensis. The beetle had been previously misnamed as the European elm flea weevil.

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Original source:

van Nieukerken EJ, Gilrein DO, Eiseman CS (2018) Stigmella multispicata Rociene & Stonis, an Asian leafminer on Siberian elm, now widespread in eastern North America (Lepidoptera, Nepticulidae). ZooKeys 784: 95-125. https://doi.org/10.3897/zookeys.784.27296