Tag: micro-CT

Dwarfs under dinosaur legs: 99-million-year-old millipede discovered in Burmese amber

A 3D reconstruction of the fossil allowed for the description of an entirely new suborder

The newly described millipede (*Burmanopetalum inexpectatum*) rendered using 3D X-ray microscopy. Image by Leif Moritz.

Even though we are led to believe that during the Cretaceous the Earth used to be an exclusive home for fearsome giants, including carnivorous velociraptors and arthropods larger than a modern adult human, it turns out that there was still room for harmless minute invertebrates measuring only several millimetres.

Such is the case of a tiny millipede of only 8.2 mm in length, recently found in 99-million-year-old amber in Myanmar. Using the latest research technologies, the scientists concluded that not only were they handling the first fossil millipede of the order (Callipodida) and also the smallest amongst its contemporary relatives, but that its morphology was so unusual that it drastically deviated from its contemporary relatives.

As a result, Prof. Pavel Stoev of the National Museum of Natural History (Bulgaria) together with his colleagues Dr. Thomas Wesener and Leif Moritz of the Zoological Research Museum Alexander Koenig (Germany) had to revise the current millipede classification and introduce a new suborder. To put it in perspective, there have only been a handful of millipede suborders erected in the last 50 years. The findings are published in the open-access journal ZooKeys.

To analyse the species and confirm its novelty, the scientists used 3D X-ray microscopy to ‘slice’ through the Cretaceous specimen and look into tiny details of its anatomy, which would normally not be preserved in fossils. The identification of the millipede also presents the first clue about the age of the order Callipodida, suggesting that this millipede group evolved at least some 100 million years ago. A 3D model of the animal is also available in the research article.

Curiously, the studied arthropod was far from the only one discovered in this particular amber deposit. On the contrary, it was found amongst as many as 529 millipede specimens, yet it was the sole representative of its order. This is why the scientists named it Burmanopetalum inexpectatum, where “inexpectatum” means “unexpected” in Latin, while the generic epithet (Burmanopetalum) refers to the country of discovery (Myanmar, formerly Burma).

Lead author Prof. Pavel Stoev says:

We were so lucky to find this specimen so well preserved in amber! With the next-generation micro-computer tomography (micro-CT) and the associated image rendering and processing software, we are now able to reconstruct the whole animal and observe the tiniest morphological traits which are rarely preserved in fossils. This makes us confident that we have successfully compared its morphology with those of the extant millipedes. It came as a great surprise to us that this animal cannot be placed in the current millipede classification. Even though their general appearance have remained unchanged in the last 100 million years, as our planet underwent dramatic changes several times in this period, some morphological traits in Callipodida lineage have evolved significantly.

The newly described millipede seen in amber. Image by Leif Moritz.

Co-author Dr. Thomas Wesener adds:

“We are grateful to Patrick Müller, who let us study his private collection of animals found in Burmese amber and dated from the Age of Dinosaurs. His is the largest European and the third largest in the world collection of the kind. We had the opportunity to examine over 400 amber stones that contain millipedes. Many of them are now deposited at the Museum Koenig in Bonn, so that scientists from all over the world can study them. Additionally, in our paper, we provide a high-resolution computer-tomography images of the newly described millipede. They are made public through MorphBank, which means anyone can now freely access and re-use our data without even leaving the desk.”

Leading expert in the study of fossil arthropods Dr. Greg Edgecombe (Natural History Museum, London) comments:

“The entire Mesozoic Era – a span of 185 million years – has until now only been sampled for a dozen species of millipedes, but new findings from Burmese amber are rapidly changing the picture. In the past few years, nearly all of the 16 living orders of millipedes have been identified in this 99-million-year-old amber. The beautiful anatomical data presented by Stoev et al. show that Callipodida now join the club.”

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Original source:

Stoev P, Moritz L, Wesener T (2019) Dwarfs under dinosaur legs: a new millipede of the order Callipodida (Diplopoda) from Cretaceous amber of Burma. ZooKeys 841: 79-96. https://doi.org/10.3897/zookeys.841.34991

3D avatars for three new rare ant species from Africa including the Obama ant

Three new, rare ant species recently discovered in Africa were named after important figures for the African biodiversity conservation – the former United States president Barack Obama, the Nigerian writer and environmental activist Ken Saro-Wiwa, and the world-renowned biologist Edward O. Wilson.

The scientists from the Okinawa Institute of Science and Technology Graduate University (OIST), who had their discovery published in the open access journal ZooKeys, used a new, revolutionary method to compile scans of the ants and create 3D avatars allowing for a unique and detailed visualisation of the insects’ insides.

https://skfb.ly/6sPvr

Curiously, the Obama ant, Zasphinctus obamai, was collected from the Kakamega Forest National Park, Kenya, located near Barack Obama’s ancestral family village. The 44th President of the United States of America is famous for his numerous initiatives towards the conservation of fragile natural habitats around the globe.

Ken Saro-Wiwa, who also has his name perpetualised in the new ant species Zasphinctus sarowiwai, was a Nigerian writer and environmental activist who, after campaigning against irresponsible oil development, was executed in 1995.

“By naming a species from threatened rainforest habitats after him, we want to acknowledge his environmental legacy and draw attention to the often-problematic conservation situation in most Afrotropical rainforests,” explain the biologists in their paper.

The third new species, Zasphinctus wilsoni, bares the name of the biologist Edward O. Wilson, whose foundation has contributed greatly to the resurrection of the Gorongosa National Park in Mozambique.

The 3D avatars were created with the help of X-ray microtomography, or micro-CT, which is a technology similar to the one used in hospitals for CT scans, but relying on much higher resolution. The three-dimensional reconstructions made it possible for the scientists to look into details as tiny as the ants’ mouthparts and even their legs and hairs. Moreover, this method does not require damaging the rare specimens.

“We saw things that nobody ever looked at,” says Dr. Hita Garcia, first author on the study and a member of the Biodiversity and Biocomplexity Unit at OIST.

While closely related ants had already been known as predators of other ant species, the scientists needed to study the data provided by the scans to confirm that the new species are top predators as well.

“Normally when you describe a new species, you don’t know much about its biology,” further explains Dr. Hita Garcia, “but with the 3D reconstructions researchers can discover details right away.”

To the biologists, these reconstructions hint at a future of virtual taxonomy with the potential to alleviate issues of time, money, and specimen damage.

Furthermore, the 3D models also allow for the data to be easily accessible from anywhere. To show this, the scientists have uploaded the reconstructions to the open access Dryad Digital Repository.

“If someone wants to see the Obama ant, they can download it, look at it, and 3D print it,” Dr. Hita Garcia points out.

“Since these ants are from very threatened habitats in Africa, we wanted to pick names that draw attention to the environment, and not just the ants,” he concludes. “The rainforests in equatorial Africa, as well as the savannah in Mozambique, needs to be protected before the habitats and animals living within them are destroyed.”

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Find the original public announcement available via the OIST’s website: https://www.oist.jp/news-center/news/2017/8/29/say-hello-3d-obama-ant

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Reference:

Hita Garcia F, Fischer G, Liu C, Audisio TL, Economo EP (2017) Next-generation morphological character discovery and evaluation: an X-ray micro-CT enhanced revision of the ant genus Zasphinctus Wheeler (Hymenoptera, Formicidae, Dorylinae) in the Afrotropics. ZooKeys 693: 33-93. https://doi.org/10.3897/zookeys.693.13012

New land snail species from Australia shows dissection not necessary to identify molluscs

Dissection might prove unnecessary when identifying new molluscs after scientists Corey Whisson, Western Australian Museum, and Dr Abraham Breure, Naturalis Biodiversity Centre, the Netherlands, and Royal Belgian Institute of Natural Sciences, Belgium, described a previously unknown land snail based on its genitalia, yet without damaging the specimen in the slightest. The new species is published in the open access journal ZooKeys.

The biologists described the first new Australian land snail species of this family for the last 33 years thanks to micro-computed tomography (micro-CT) and reconstruction with specialised software. This novel method, likely applied for identification of molluscs for the first time in history, uses X-rays to create cross-sections of the genitalia, so that a 3D model can be created without damaging the specimen. This can be then compared to known related taxa’s genitalia in order to show if there are enough differences to prove species delimitation.

The scientists note that despite the satisfying results, micro-CT is time-consuming and “quite laborious” approach. “However, in the case of a single or just a few specimens, this may be an alternative to destructive dissection,” says Dr Abraham Breure in his personal blog.

The new land snail, called Bothriembryon sophiarum after Dr Abraham Breure’s wife Sophie J. Breure and Corey Whisson’s first daughter Sophie Jade Whisson, can only be found along a 180-kilometre line running across the escarpment and cliff tops of the Baxter Cliffs and Hampton Ranges in Western Australia. Given its restricted distributional range, it is considered a short-range endemic.

The mollusc is characterised with a slender high-spired shell, built specifically for the demanding nature of its habitat. Dwelling in rocky limestone substrate, which is often fractured with narrow cracks and fissures, the snail has developed a slender shell, so that it can move easily through cavities and under rocks. On the other hand, being predominantly cream in colour with reddish or greyish brown blotches, it successfully blends with the limestone.

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Original source:

Whisson CS, Breure ASH (2016) A new species of Bothriembryon (Mollusca, Gastropoda, Bothriembryontidae) from south-eastern Western Australia. ZooKeys 581: 127-140. doi:10.3897/zookeys.581.8044

Single no more: First females of a Madagascan chameleon described with modern technologies

The first females of a scarcely known chameleon species from Northeast Madagascar have been described. Because of lack of genetic data, X-ray micro-computed tomography scans of the chameleon’s head were used for species assignment. Regrettably, the habitats of this and many other chameleon species are highly threatened by the ongoing deforestation in Madagascar. The study is published in the open-access journal Zoosystematics and Evolution.

Chameleons belong to the most popular animals of Madagascar and have been quite intensively studied in the past. However, many new species are still being discovered and described, and several species are only known by a single or a few specimens. Likewise, the chameleon species Calumma vatosoa from northeastern Madagascar was described in 2001 based on a single male. The identity of females of this species has been unclear until now.

Recently, the PhD student David Proetzel of the herpetology section of the Zoologische Staatssammlung Munchen (ZSM), Germany, found specimens of female chameleons in the collection of the Senckenberg Museum, Frankfurt am Main, Germany, that looked similar to Calumma vatosoa. The problem was, how to prove this? The specimens from Frankfurt were collected back in 1933 and therefore, the extraction of DNA for genetic analysis was not possible anymore.

Researchers of the ZSM have been using X-ray micro-computed tomography scans for a few years to study the internal morphology of organisms in a non-invasive way.

“With the help of Micro-CT you can investigate even the skeleton of very valuable samples like holotypes without destroying them,” explains David Proetzel.

“In chameleons the morphology of the skeleton, especially the skull, contains important characteristics that distinguish different species,” explains the researcher. “Here, the comparison of the skulls of the male and the female showed that they belong to the same chameleon species. With the help of modern technology we could describe females of Calumma vatosoa for the first time, and add another distribution locality of this species.”

“The habitats of many chameleon species, and not only, are highly threatened by the ongoing deforestation in Madagascar and we need rapidly to expand our knowledge about the biodiversity, so that suitable conservation measures can be taken,” he stresses.

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Original source:

Proetzel D, Ruthensteiner B, Glaw F (2016) No longer single! Description of female Calumma vatosoa (Squamata, Chamaeleonidae) including a review of the species and its systematic position. Zoosystematics and Evolution, 92 (1): 13-21. doi: 10.3897/zse.92.6464