Saturday, 19 August 2017

Neovahlkampfia nana: A new species of Heterolobosean Amoeba from the Czech Republic.

Heteroloboseans are flagellated Amoebas closely related to Slime Molds, and generally though to be the most primitive group of flagellated Eukaryotes (i.e. the group closest to the first such organisms to have appeared. They typically have a life-cycle which includes both flagellated and non-flagellated stages, as well as an inert cyst stage that can survive periods of hostile conditions, such as a cold, or dry season.

In a paper published in The Journal of Eukaryotic Microbiology on 13 July 2017, Tomáš Tyml of the Faculty of Science at the University of South Bohemia and the Faculty of Science at Masaryk University, Luis Lares-Jim énez, also of the Faculty of Science at Masaryk University, Martin Kostka, also of the Faculty of Science at the University of South Bohemia, and Iva Dykov á, again of the Faculty of Science at Masaryk University, describe a new species of Heterolobosean Amoeba from the gills of Rainbow Trout, Oncorhynchus mykiss, infected with an unknown nodular gill disease in the Czech Republic.

The new species is place in the genus Neovahlkampfia, which currently only contains a single species, Neovahlkampfia damariscottae, a marine Amoeba from an estuary in Maine, which was formerly placed in the genus Vahlkampfia until a genetic analysis sugested that it should be excluded from this group. It is given the specific name Neovahlkampfia nana, in reference to the small size of this species, which reached 8–15 μm in length.

Globular form of Neovahlkampfia nanawith nucleus (n), mitochondria (m), electron-dense structure (es), and dense bodies (db) in cytoplasm. Tymel et al. (2017).

Neovahlkampfia nana was identified as a a member of the Heterolobosea and a close relative of Neovahlkampfia damariscottae by genetic analysis (morphological comparisons of Amoebae are close to worthless). The species adopted a number of forms in response to changes in conditions, but these were essentially behavioural, rather than true metamorphoses, and the Amoebas were not observed to produce a flagellated or cyst stage (though this does not necessarily mean that they cannot do this).

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Explosion kills one and injures five as theft from gas pipeline goes wrong in Veracruz State, Mexico.

At least one person has died and another five have been injured following an explosion on a natural gas pipeline near Ixtaczoquitlán in Veracruz State, Mexico, apparently caused by thieves drilling into the pipeline on the morning of Saturday 19 August 2017. No details about the dead person have been released at this time, but the injured have been identified as men aged 20, 25, 36 and 65, plus a pregnant 15-year-old girl, all of whom suffered extensive burns; it is not clear whether any of the known casualties were involved in the theft, or were Innocent victims of the incident. 

Burning pipeline in Veracruz State, Mexico, following in explosion on Saturday 19 August 2017. Quadratin Edomex.

The fire has been brought under control by emergency services after the pipeline operators, Pemex, stopped the flow of gas through the pipeline, depriving the fire of fuel. It is likely that the incident was caused by thieves attempting to steal oil, rather than gas, from the pipeline. Thefts of oil from pipelines in Mexico have risen almost ninefold in the last decade, driven by growing economic inequality and rising fuel prices.

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Nothodichocarpum lingyuanensis: A new species of Angiosperm from the Jehol Biota.

The Early Cretaceous Yixian Formation of Lioaning Province, China, has produced a wide range of well preserved animals and plants, including many Vertebrates and Insects, collectively known as the Jehol Biota. The plants from these deposits include the earliest known diverse community of Angiosperms (Flowering Plants), providing a valuable insight into the earliest members and initial diversification of this group.

In a paper published in the journal Acta Geologica Sinica on 1 February 2017, Han Gang of the Hainan Tropical Ocean University and the Palaeontological Center at Bohai University, Liu Zhongjiang, also of the Palaeontological Center at Bohai University, and of the Shenzhen Key Laboratory for Orchid Conservation and Utilization at the National Orchid Conservation Center of China and Orchid Conservation & Research Center of Shenzhen, and Wang Xin of the State Key Laboratory of Palaeobiology and Stratigraphy at the Nanjing Institute of Geology and Palaeontology, describe a new species of Angiosperm from the Jehol Biota.

The new species is named Nothodichocarpum lingyuanensis, where 'Nothodichocarpum' means 'false-Dichocarpum', in reference to a modern genus of herbaceous Flowering Plants in the Ranunculaceae (Buttercup Family) that it superficially resembles, and 'lingyuanensis' means 'from Lingyuan', the locality where the fossils were discovered. 

 Nothodichocarpum and its details. (a) Holotype including branches, leaves, and flowers. Scale bar is 1 cm. (b) One of the leaves with a midrib (arrow). Scale bar is 1 mm. (c) Another narrow obovate leaf with attenuated tip and several teeth (black arrows), overlapped by a young flower including two carpels (1, 2) and at least one male part (white arrow). Scale bar is 1 mm. (d) Pinnate venation in one of the leaves. Scale bar is 0.5 mm. (e) Opposite branching. Note the main branch (2), axillary branch (1), subtending leaf (3), and leaves (l). Scale bar is 1 mm. (f) Three flowers (1-3) of different stages overlapping leaves. Note several male parts (arrows) beside carpels. Scale bar is 1 mm. (g) Two divergent, basally coalescent follicles and two male parts (arrows). Note the spatial relationship between the follicles and male parts. Scale bar is 2 mm. (h), Two young basally coalescent carpels (1-2). Scale bar is 1 mm. (i) Detailed view of the right male part in (g). Scale bar is 0.5 mm. (j) The right fruit in (g) showing abutting seeds (black arrows) inserted along the dorsal vein (white arrow). Scale bar is 1 mm. (k) Four abutting seeds (1-4) in the fruit shown in (g). Note seed 4 is apparently connected to the dorsal of the fruit (black arrow). Scale bar is 1 mm. Han et al. (2017).

Nothodichocarpum lingyuanensis shows a number of unusual features, including the arrangement of the leaves, and the structure of the flower. 

The leaves of Nothodichocarpum are opposite, that is to say arranged in pairs which are opposite one-another on the stem. This is a very common arrangement in modern Flowering Plants, and is also found in a variety of other, non-flowering, Plants, but has not previously been recorded in an early Angiosperm. However re-examination of Archaefructus, another Flowering Plant from the Jehol Biota, and a candidate for the most primitive Angiosperm known, suggests that this plant may also have had an opposite arrangement of leaves, suggesting that this may have been the condition in the very first Flowering Plants.

Sketches of Nothodichocarpum. (a) Sketch showing the physical connection among various parts. Green: leaf; gray: leaf vein; red: follicle/carpel; black: branch; blue: male part. Scale bar is 10 mm. (b) The fruit shown in (g) and (j) above. Note the seeds inserted onto the dorsal vein (right) and male part (blue). Scale bar is 1 mm. (c), Semi-idealised sketch of the leaf shown in (c) above. Han et al. (2017).

Nothodichocarpum lingyuanensis is preserved with both fruit and flowers, enabling examination of both these structures, an unusual opportunity in such an early Plant. The seeds are enclosed within an ovule, which considered to be one of the defining features of an Angiosperm, but the 'flowers' are arranged in a way quite unlike that seen in modern Plant, suggesting that Nothodichocarpum lingyuanensis represents an early stage in the development of the Angiosperms, with a floral structure on the way to developing into a flower, but which we would not necessarily recognise as such.

Details of the flowers of Nothodichocarpum under Scanning Electron Microscope. (a) Basal portion of the fruit shown in top (g). Note the scars left by fallen off male parts (arrows), and their spatial relationship with the carpel (c) and filament (f). Scale bar is 1 mm. (b) A filament (f, white arrow) subtended by a bract (b, black arrow). This male part corresponds to the one marked by left white arrow in above (a). Scale bar is 0.1 mm. (c) Detailed view of rectangle in (a) above. Note spatial relationship among the bract (b) filament (f) in its axil, and carpel (c). Scale bar is 0.1 mm. (d) Detailed view of the right follicle of fruit 2 in top (f). Note the relationship between the carpel (c, white arrow) and male part (black arrows). Scale bar is 1 mm. Han et al. (2017).

The flower of Nothodichocarpum lingyuanensis appears to have had four male parts, two of which were opposite the female folicles and two located between; this is represented by two surviving parts, one in each of these positions and two scars, where the remaining two would be predicted to be. Each of these has a bract beneath which appears to support it. This places the male and female reproductive parts of the plant together at the end of a stem, but does not integrate them into a single flower; forming a structure different to that seen in any living or fossil plant (though a number of early fossil Angiosperms are identified as such from preserved fruiting bodies, without the flowers being known, so they could presumably have supported structures similar to those seen in Nothodichocarpum.

 Reconstruction of Nothodichocarpum in its flower (a) and fruit (b) stages. Note the dorsal vascular bundle connected with seeds in an opened fruit (b). Han et al. (2017).

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Eleven injured by landslide in Gifu Prefecture, Japan.

Eleven people have been injured, three of them seriously, after a landslide hit a section of the Chuo Expressway in Mizunami, Gifu Prefecture, Japan, at about 9.30 pm local time on Friday 18 August 2017. The event buried a section of the road over sixty meters long in debris up to a meter depth, strikingfour vehicles, three cars and a truck, with all of the injured being inside these vehicles. The event happened after several days of heavy rain in the area. Landslides are a common problem after severe weather, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall.

 Clean up operation following the 18 August 2017 Mizunami landslide. The Mainichi.

This August has been the wettest in Japan for 40 years, with many central parts of the country experiencing sixteen straight days of rain, and Gifu Prefecture receiving over a 100 mm of rain on Thursday alone. This has bee driven by an area of high pressure over the Sea of Okhotsk (the Okhotsk High), which forms each summer, bringing cool moisture-laden winds to Japan, Korea and the Russian Far East, and which has been exceptionally strong this year.

The approximate location of the 18 August 2017 Mizunami landslide. Google Maps.

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Chuo Expressway in Gifu Prefecture
Chuo Expressway in Gifu Prefecture

Magnitude 4.8 Earthquake to the north of Puerto Rico.

The United States Geological Survey recorded a Magnitude 4.8 Earthquake at a depth of 42 km roughly 50 km north of Puerto RIco, slightly before 4.15 pm local time (slightly before 8.15 pm GMT) on Friday 18 August 2017. This was a moderate quake, and at some depth as well as some way offshore, and there are no reports of any casualties or serious damage, though the quake was felt across Peurto Rico.
 The approximate location of the 18 August 2017 Puerto Rico Earthquake. USGS.
Puerto Rico is located at the northeastern fringe of the Caribbean Tectonic Plate. The Atlantic Plate (strictly speaking, an extension of the South American Plate which runs to the northeast of the Caribbean) is being subducted beneath this. The subduction of the Atlantic Plate beneath the Caribbean Plate is not a smooth process, with the two plates constantly sticking together then breaking apart as the tectonic pressure builds up, causing Earthquakes in the process, though since the boundary between the two plates is some way to the north and east of the islands, Earthquakes in this area tend to be both deep and offshore, which lessens their destructive potential.
 The subduction of the Atlantic Plate beneath the Caribbean Plate fuels the volcanoes of the Lesser Antilles Volcanic Arc. George Pararas-Carayannis.
Witness accounts of quakes can help geologists to understand these events and the rock structures that cause them. If you felt this quake (or if you were in the area but did not, which is also useful information) you can report it to the USGS here.
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Eruption in Mount Karinici, Indonesia.

The Darwin Volcanic Ash Advisory Centre has reported an eruption on Mount Karinici, Sumatra, that produced an ash column 4.3 km high on Sunday 13 August 2017. This column persisted for several days, having drifted only 30 km to the southwest by Thursday 17 August. Mount Karinici, which is located in the Karinici Sablat National Park, on the border between West Sumatra and Jambi Provinces, is the highest volcano in both Sumatra and Indonesia, and one of the most active, typically undergoing several eruptions in the course of a year. However most of these eruptions are quite small; the volcano is not considered to be particularly dangerous, and is a popular tourist attraction.

The location of Mount Karinici, Sumatra. Google Maps.

The Indo-Australian Plate, which underlies the Indian Ocean to the west of Sumatra, is being subducted beneath the Sunda Plate, a breakaway part of the Eurasian Plate which underlies Sumatra and neighbouring Java, along the Sunda Trench, passing under Sumatra, where friction between the two plates can cause Earthquakes. As the Indo-Australian Plate sinks further into the Earth it is partially melted and some of the melted material rises through the overlying Sunda Plate as magma, fuelling the volcanoes of Sumatra.

The Subduction zone beneath Sumatra. NASA/Earth Observatory.

The two plates are not directly impacting one-another, as occurs in the subduction zones along the western margins of North and South America, but at a steeply oblique angle. This means that as well as the subduction of the Indo-Australian plate beneath the Sunda, the two plates are also moving past one-another. This causes rifting within the plates, as parts of each plate become stuck to the other, and are dragged along in the opposing plate's direction. The most obvious example of this is the Sumatran Fault, which runs the length of Sumatra, with the two halves of the island moving independently of one-another. This fault is the cause of most of the quakes on the island, and most of the island's volcanoes lie on it.

The movement of the tectonic plates around Sumatra. NASA/Earth Observatory.
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Friday, 18 August 2017

Chilesaurus diegosuarezi: How an enigmatic Dinosaur sheds light on the evolution of the whole group.

Chilesaurus diegosuarezi is a Late Jurassic Dinosaur from the Toqui Formation of Chile first described in 2015. It shows an unusual combination of features, combining elements usually associated with Therapods, Protosauropods and Ornithischian Dinosaurs. At the time of its description it was considered that, on the balance of probability, it was a Tetanuran Theropod (the group that also includes Tyrannosaurids, Megalosaurids, Ornithomimids, Allosaurids, Maniraptorforms, and Birds), with a number of unTheropod-like features that derive from its adaptation to a herbivorous lifestyle, leading to convergent evolution of some features with the herbivorous Protosauropods and Ornithischians.

However, in a paper published in March this year (2017), a group of palaeontologists led by Matthew Baron of the Department of Earth Sciences at the University of Cambridge and the Department of Earth Sciences at the Natural History Museum, presented the results of a cladistic study of Dinosaur phylogenetics (computerised analysis of relationships within the group based entirely upon shared common features rather than assumed relationships), which appeared to overturn some long-held views on Dinosaur evolution, most notably that the Ornithischians had diverged from other Dinosaurs before the split between Theropods and Sauropods; Baron et al.'s analysis suggested that this was an inaccurate and antiquated view, based upon the value attributed to the structure of the hip joint by Victorian palaeontologists, and that in fact the Ornithischians were more closely related to the Theropods than the Sauropods, which were the first group to split away from other Dinosaurs, early in the history of the group.

In a new paper published in the journal Biology Letters on 15 August 2017, Mathew Baron and Paul Barrett, also of the Department of Earth Sciences at the Natural History Museum, re-investigate the phylogentic position of Chilesaurus diegosuarezi, with a view to using this enigmatic species to better understand the history of the whole group.

Using this methodology, Baron and Barrett conclude that Chilesaurus diegosuarezi is in fact an Ornithischian rather than a Tetanuran Theropod, although it is the closest known species to the base of this group, holding a sister-group relationship to the rest of the Ornithischia, which are all more closely related to one-another than to Chilesaurus diegosuarezi. This lends strong support to the theory that Theropods and Ornithischians are closely related, with the 'primitive' Chilesaurus diegosuarezi being an Ornithischian that retains a number of Theropod-like features,

 Simplified time-calibrated strict consensus tree in which Chilesaurus is recovered within Ornithischia. Silhouettes represent supraspecific taxa—from left to right: Sauropodomorpha, Heterodontosauridae, Genasauria and Neotheropoda. Baron & Barrett (2017).

Chilesaurus diegosuarezi lacks a number of features usually thought of as being diagnostic of Ornithischian Dinosaurs, such as the predentary bone at the anterior end of the lower jaw, which presumably precluded its inclusion in the Ornithischia in its original description. However under the new classification proposed by Baron and Barrett this is not a problem, as these features are presumed to have evolved after the ancestors of  Chilesaurus diegosuarezi split away from the rest of the group.

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