Tag: physiology

The first drywood termite known to use snapping stick-like mandibles to defend its colony

Tasked to defend the colony from attackers, the specialised soldier caste in some termite species has evolved various impressive mechanisms, including plug-like heads – meant to block intruding ants trying to invade their lairs, and mouthparts designed to bite and pierce.

Still, there are even more spectacular soldiers, such as a recently discovered drywood termite species, whose unique long and slender, stick-like snapping mandibles produce one of the highest acceleration speeds measured in a living organism. Rather than bite, these peculiar ‘jaws’ deliver powerful strikes at enemies bold enough to stand in the way of the soldier termite and its colony.

The scientists describe the new termite’s specialty in detail:

“Roisinitermes employs a unique strategy of snapping, achieved by long and slender mandibles pressed against each other in a defensive encounter. When this potential energy is released, the left mandible springs over the right and the resultant snap is forced onto the opponent if it is in the path of the strike.”

Discovered in Cameroon, this striking species is the first drywood termite found to rely on snapping mandibles as a defense strategy. Given that until now there had been a single subfamily (Termitinae) known to have developed such, the very existence of the new insect poses a whole new set of questions before scientists. Have snapping mandibles evolved independently in two evolutionary lineages? Or, is it that these groups share a distant kin relationship which has gone unnoticed for that long?

The new drywood termite, which is also assigned to a new genus, is named Roisinitermes ebogoensis, and is described in the open access journal ZooKeys by an international team of researchers, led by Dr Rudolf Scheffrahn of the Institute for Food and Agricultural Sciences at University of Florida, Davie, USA. Although this particular species is not thought to be a pest, some drywood termites cause serious damage to wooden structures around the world.

Both colonies studied by the scientists were found near the Ebogo II village, which also stands behind the name of the species. The first unusual colony to draw the attention of the scientists was collected from a forest on an island in the Nyong River, where it lived in a thin (3 cm) and long (over 3 m) broad-leaf tree branch suspended from a canopy. The second one – in a 15-mm thick dead liana branch hanging from a tree in a nearly pristine rainforest.

The team expects that future research will shed more light on the origins and evolution of the newly discovered termite.

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Original source:

Scheffrahn RH, Bourguignon T, Akama PD, Sillam-Dussès D, Šobotník J (2018) Roisinitermes ebogoensis gen. & sp. n., an outstanding drywood termite with snapping soldiers from Cameroon (Isoptera, Kalotermitidae). ZooKeys 787: 91-105. https://doi.org/10.3897/zookeys.787.28195

New species of frog from the Neotropics carries its heart on its skin

In the Neotropics, there is a whole group of so-called glassfrogs that amaze with their transparent skin covering their bellies and showing their organs underneath. A recently discovered new species from Amazonian Ecuador, however, goes a step further to fully expose its heart thanks to the transparent skin stretching all over its chest as well as tummy.

The new amphibian is described by a team of scientists led by Dr. Juan M. Guayasamin, Universidad San Francisco de Quito, Ecuador, in the open access journal ZooKeys.

It can also be distinguished by the relatively large dark green spots at the back of its head and the foremost part of the body. Additionally, the species has a characteristic long call.

The new frog is named Hyalinobatrachium yaku, where the species name (yaku) translates to ‘water’ in the local language Kichwa. Water and, more specifically, slow-flowing streams are crucial for the reproduction of all known glassfrogs.

The reproductive behaviour is also quite unusual in this species. Males are often reported to call from the underside of leaves and look after the egg clutches.

Having identified individuals of the new species at three localities, the researchers note some behavioural differences between the populations. Two of them, spotted in the riverine vegetation of an intact forest in Kallana, have been calling from the underside of leaves a few metres above slow-flowing, relatively narrow and shallow streams. Another frog of the species has been observed in an area covered by secondary forests in the Ecuadorian village of Ahuano. Similarly, the amphibian was found on the underside of a leaf one metre above a slow-flowing, narrow and shallow stream.

However, at the third locality – a disturbed secondary forest in San José de Payamino – the studied frogs have been perching on leaves of small shrubs, ferns, and grasses some 30 to 150 cm above the ground. Surprisingly, each of them has been at a distance greater than 30 metres from the nearest stream.

The researchers note that, given the geographic distance of approximately 110 km between the localities where the new species has been found, it is likely that the new species has a broader distribution, including areas in neighbouring Peru.

The uncertainty about its distributional range comes from a number of reasons. Firstly, the species’ tiny size of about 2 cm makes it tough to spot from underneath the leaves. Then, even if specimens of the species have been previously collected, they would be almost impossible to identify from museum collection, as many of the characteristic traits, such as the dark green marks, are getting lost after preservation. This is why the conservation status of the species has been listed as Data Deficient, according to the IUCN Red List criteria.

Nevertheless, the scientists identify the major threats to the species, including oil extraction in the region and the related water pollution, road development, habitat degradation and isolation.

“Glassfrogs presumably require continuous tracts of forest to interact with nearby populations, and roads potentially act as barriers to dispersal for transient individuals,” explain the authors.

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Original source:

Guayasamin JM, Cisneros-Heredia DF, Maynard RJ, Lynch RL, Culebras J, Hamilton PS (2017) A marvelous new glassfrog (Centrolenidae, Hyalinobatrachium) from Amazonian Ecuador. ZooKeys 673: 1-20. https://doi.org/10.3897/zookeys.673.12108

The first crowdfunded study in Japan: Micro X-ray observation of a fleshy brittle star

Not only have scientists from Japan performed the first non-destructive morphological observations on the Fleshy brittle star, Asteronyx loveni, using micro X-ray tomography, but they also published their research as the first study supported via crowdfunding in the Asian country.

The team leader, Dr. Masanori Okanishi, Ibaraki University, managed to raise part of the funds via Japan’s pioneering crowd-funding platform academist. The study by Dr. Masanori Okanishi, Dr. Toshihiko Fujita, National Museum of Nature and Science, Tsukuba, Yu Maekawa and Dr. Takenori Sasaki, University of Tokyo, is now openly available in the open access journal ZooKeys.

While taxonomy is generally considered as “minor” and “basic” discipline within biology, it could be extremely strenuous for taxonomists to apply for and receive funding. Thus, Dr. Okanishi jumped to the conclusion that his planned study might have a go via crowdfunding instead.

Dr. Okanishi approached academist in April 2014, when he was a Postdoctoral researcher at Kyoto University. Titled “Taxonomy of bathyal euryalid ophiuroids”, it was not long before his research project successfully raised 634,500 JPY (ca. 5,600$).

Having already stumbled across several undescribed species of the brittle star genus Asteronyx, the scientists directed the raised funds towards the genetic and morphological analysis of Asteronyx loveni.

As suggested by its common name, the fleshy brittle star (Asteronyx loveni) is covered by thick skin, making it particularly difficult for scientists to observe the body in detail without dissolving the skin. However, modern computed tomography with micrometer resolution allowed for the 3D images of skeletal ossicles and soft tissues to be constructed with no physical intervention whatsoever.

“The present case indicates that crowdfunding will increase the chances to finance the funds for researchers in those disciplines and activate the research area,” conclude the authors.

The newly discovered brittle star species are yet to be published.

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Original source:

Okanishi M, Fujita T, Maekawa Y, Sasaki T (2017) Non-destructive morphological observations of the fleshy brittle star, Asteronyx loveni using micro-computed tomography (Echinodermata, Ophiuroidea, Euryalida). ZooKeys 663: 1-19. https://doi.org/10.3897/zookeys.663.11413