Monday, 31 October 2022

Tuebingosaurus maierfritzorum: A new species of Massopodan Sauropodomorph Dinosaur from the Palaeontological Collection of the University of Tübingen.

The Palaeontological Collection of the University of Tübingen contains one of the largest assemblages of Sauropodomorph Dinosaurs in Europe, but also one of the least studied. Much of this material was collected from sites around Tübingen, Aixheim and Löwenstein in the nineteenth and early twentieth centuries and classified under the genus Plateosaurus

The genus Plateosaurus was once used to classify almost all non-Sauropod Sauropodomorph Dinosaurs, and by the mid twentieth century contained over 20 species, of which only four are considered valid today. Unfortunately, while it is now recognised that the non-Sauropod Sauropodomorph Dinosaurs are a more diverse group than once understood, and that understanding this diversity is the key to understanding the emergence of the true Sauropods, one of the most remarkable groups of organisms ever to appear on Earth, several rival schemes for the classification of this group have appeared, hampering this understanding.

In a paper published in the journal Vertebrate Zoology on 8 September 2022, Omar Rafael Regalado Fernández of the Fachbereich Geowissenschaften an der Universität Tübingen, and Ingmar Werneburg, also of the Fachbereich Geowissenschaften an der Universität Tübingen, and of the Senckenberg Centre for Human Evolution and Palaeoenvironment an der Universität Tübingen, describe a new species of Sauropodomorph Dinosaur from the Palaeontological Collection of the University of Tübingen, based upon a specimen, GPIT-PV-30787, collected from Lower Dinosaur Bed at Obere Mühle in 1932.

The complex nature of Sauropodomorph Dinosaur taxonomy meant that Regalado Fernández and Werneburg were obliged to carry out multiple phylogenetic analyses in order to try to accommodate specimen GPIT-PV-30787 into the competing phylogenies for the group. Fortunately, these produced reasonably consistent results, with the specimen being found to be closely related to Schleitheimia schutzi, making it a Massopodan Sauropodomorph, close to the origin of the true Sauropods.

Based upon this information, Regalado Fernández and Werneburg describe specimen GPIT-PV-30787 as the holotype of a new species, giving it the name Tuebingosaurus maierfritzorum, where 'Tuebingosaurus' refers to Tübingen and 'maierfritzorum' honours Wolfgang Maier, professor of evolutionary zoology in Tübingen from 1987 to 2007, and Uwe Fritz, former editor-in-chief of the journal Vertebrate Zoology.

Specimen GPIT-PV-30787 comprises a complete pelvis (three sacral vertebrae, two ilia, two pubes, two ischia), five anterior caudal vertebrae, four chevrons, left femur, left tibia, left and right fibulae, left astragalus, left calcaneum, metatarsal I, and pedal fingers 3 and 4.

Reconstruction of Tuebingosaurus maierfritzorum, as a quadruped Dinosaur, using the outline of Riojasaurus as a base, next to the silhouette of Friedrich von Huene. The drawing of the bones is based on and modified from the original illustrations of specimen 'GPIT IV' (the name originally ascribed to GPIT-PV-30787) by von Huene. The right fibula is marked in grey as it was found nearby with similar measurements to the left fibula and has been assumed to be part of the same individual. Regalado Fernández & Werneburg (2022).

Regalado Fernández and Werneburg's phylogeny suggests that Tuebingosaurus maierfritzorum is a Massopodan, making it the earliest member of the group known from the Upper Triassic Trossingen Beds. Despite this taxonomic placement, Tuebingosaurus maierfritzorum still shares a number of features more generally associated with Plateosaurian Sauropodomorphs, most notably a heel-like projection in the posterior part of the ischiadic peduncle of the ilium and a straight lateral margin in metatarsal II, features which led to the assumption that this was a specimen of Plateosaurus

This presence of Plateosaurian-like features in early Massopodan Dinosaurs is unlikely to be unique to Tuebingosaurus maierfritzorum, and re-examination of other historic specimens at Tübingen and other palaeontological collections may provide more examples, helping to unravel the origins of the Sauropods.

Reconstruction of the last moments in the life of Tuebingosaurus maierfritzorum (collection number of the painting: GPIT-PV-41827). The cortical bone on the left side of the fossil is fractured into flakes, which can be explained if the carcass was exposed over a long time on the mud, two to four years, before being buried – in the reconstruction, the Animal will fall to its right body side. The reconstruction shows the animal sinking in a mud trap, attacked by a Rauisuchian, Teratosaurus, which has also been found in the Trossingen Formation in Baden-Württemberg. In the background, a herd of Plateosaurus trossingensis runs away from the scene. The flora in the swamp is reconstructed based on fossils from the Germanic basin, with shoots of Horsetails and Ferns covering the swamp and a forest comprising Cycads (Taeniopteris), Lycophytes (Lepacyclotes) and Coniferous Plants (Brachyphyllum). Regalado Fernández & Werneburg (2022).

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Sunday, 30 October 2022

Fireball over northern California.

The American Meteor Society has received reports of a bright fireball meteor being seen over northern California slightly before 9.30 pm local time on Thursday 28 October 2022 (slightly before 4.30 am on Friday 29 October, GMT). People witnesses observing the event from much of California, as well as parts of Nevada, reporting that the meteor moved roughly east to west, to the north of San Francisco. A fireball is defined as a meteor (shooting star) brighter than the planet Venus. These are typically caused by pieces of rock burning up in the atmosphere, but can be the result of man-made space-junk burning up on re-entry. 

Heat map showing areas where sightings of the meteor were reported (warmer colours indicate more sightings)and the apparent path of the object (blue arrow). American Meteor Society. 

Objects of this size probably enter the Earth's atmosphere several times a year, though unless they do so over populated areas they are unlikely to be noticed. They are officially described as fireballs if they produce a light brighter than the planet Venus. The brightness of a meteor is caused by friction with the Earth's atmosphere, which is typically far greater than that caused by simple falling, due to the initial trajectory of the object. Such objects typically eventually explode in an airburst called by the friction, causing them to vanish as an luminous object. However, this is not the end of the story as such explosions result in the production of a number of smaller objects, which fall to the ground under the influence of gravity (which does not cause the luminescence associated with friction-induced heating).

These 'dark objects' do not continue along the path of the original bolide, but neither do they fall directly to the ground, but rather follow a course determined by the atmospheric currents (winds) through which the objects pass. Scientists are able to calculate potential trajectories for hypothetical dark objects derived from meteors using data from weather monitoring services.

Witness reports can help astronomers to understand these events. If you witness a fireball-type meteor over the US you can report it to the American Meteor Society here. 

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Saturday, 29 October 2022

Understanding the traditional glassmaking industry of Bida, west-central Nigeria.

The city of Bida sits on the Lanzu River in west-central Nigeria, close to where that river flows into the Niger in an area bordered by the Sahel region to the north and savanna grasslands to the south. The people of the city belong to the Nupe ethnic group, and attribute the founding of the city to the legendary hero Tsoede, who is said to have ruled over a Nupe kingdom in the area. While culturally distinct, the Nupe civilisation clearly shows influences from neighbouring groups, particularly the Yoruba polities to the south and then Hausa and Fulani of the Sahel Region. The people are predominantly Muslim, speak a language similar to Yoruba, and practice many crafts common to other groups in the region. One notable such craft is glassmaking, practised largely by a Nupe subgroup called the Masagá.

Although fully accepted as part of the wider Nupe community, the Masagá claim to be descended from migrants from Egypt, who settled in Bida during the reign of Tsoede, bringing with them the their glassmaking skills.

All glass produced in the area today is made from recycled imported glass. This practice began in the late nineteenth century, when European-manufactured glass bottles first reached the area. However, the Masagá are known to have manufactured raw glass prior to the arrival of this new material, with their own oral tradition claiming that they brought both their skills and their tools with them when they migrated from Egypt.

This locally produced glass is referred to by the Masagá as 'bikini', while recycled European glass is called 'kwálaba', which can be literally translated as 'bottle'. The word kwálaba could possibly be related to the Arabic قالب (qulab), which implies a mould used to shape glass, but this in itself does not prove the Egyptian ancestry claim. The terms bikini and kwálaba represent important methodological differences, with bikini representing a two-step process in which glass as a raw material is made in one workshop then delivered to a second workshop to be crafted into end products, while kwálaba represents a single step process, in which pre-made glass is molded into new forms. However, in recent decades, the process has become simplified, with both steps being carried out in a single workshop, called an 'estwa', and, since 1969, the process of making bikini ceasing altogether.

In a paper published in the journal African Archaeological Review on 20 October 2022, Lesley Lababidi of Lagos, Nigeria, Abidemi Babatunde Babalola of the University of Cambridge and the British Museum, Bernard Gratuze of the Institut de Recherche sur les ArchéoMATériaux Centre Ernest-Babelon at the Université d’Orléans, Joëlle Rolland of Paris, France, and Emmanuel Véron and  Aurélien Canizares of Conditions Extrêmes et Matériaux: Haute Température et Irradiation at the Université d’Orléans, present the results of a study which aimed to understand the processes involved in the making of bikini glass by reconstructing that process and carrying out laboratory analysis of both the material produced by this reconstruction and recovered from archaeological sites. 

Map of Nigeria showing the location of Bida. Lababidi et al. (2022).

The production of glass artefacts involves two steps; primary production (making glass) and secondary production (making things out of that glass. The primary production phase begins with the sourcing of materials needed to make glass, including silica in the form of sand or rock, a fluxing agent, typically an alkali metal such as sodium or potassium, and alumina or lime to act as a stabilising agent. The secondary phase can involve the manufacture of a wide range of glass objects, and may be carried out at the same location as the primary phase, or a separate location, sometimes far away. This process typically involves remelting the previously made glass, although in some cases artefacts are made by working glass cold. 

Primary glass making in North Africa has been studied fairly extensively by archaeologists, but relatively little attention has been paid to traditions of glassmaking south of the Sahara, although the practice is known to have been carried out at Ile-Ife in southwest Nigeria since at least the fourteenth century AD. 

Secondary glassmaking has an even longer history in sub-Saharan Africa, with examples of recycled glass known from Chibuene in southern Mozambique, an important Indian Ocean trading port, dating back to the sixth-tenth century AD. Recyling of glass also appeared at Gao in Mali between the ninth and twelfth centuries AD, where glass beads from the Islamic world were used as a source of material, something which may also have happened at Igbo-Ukwu in Anambra Stats, Nigeria. Similar secondary production may also have been carried out at Mkokotoni on the coast of Tanzania, where imported beads have been found alongside beads of apparent local manufacture, at a site dated to the early second millennium AD. Secondary production of glass is also thought to have occurred in Southern Africa from the tenth to fifteenth centuries, and possibly as late as the nineteenth century.

Thus the secondary production of glass from imported sources appears to have been a widespread if fairly minor industry in sub-Saharan Africa from the middle of the millennium AD to the middle of the second millennium AD, and to have become increasingly common in the second half of the second millennium AD, as more glass from European sources became available.

To date, very little archaeological investigation has been carried out in the Nupeland area, none of which has produced any evidence for glassmaking. However, historical records for the practice do exist, and go back to 1856, when Thomas Jeferson Bowen, an American Christian missionary, recorded that bikini glass was manufactured at three towns in the area. Subsequent observations of glassmaking in Nupeland were made by the German explorer Leo Frobenius in 1912, the British anthropologist Fred Nadel in the 1940s, and the Swiss travel-writer René Gardi in 1969.

Thus there is a continuous historical record of the manufacture of bikini glass from local materials dating back to the mid-nineteenth century, with this practice clearly differentiated from the practice of making glass from recycled European bottles. However, the increased availability of European glass in a variety of colours appears to have led to the demise of bikini glass making, as the recycling process was both easier than primary manufacture and could produce a wider range of finished items.

Thus, while there is a historical record of bikini glassmaking, and this was still happening within living memory, this practice has now ceased. Lababidi et al. therefore set out to try to recreate the process by which this glass was manufactured, starting with a series of interviews with older members of the Masagá community, followed by an attempt to recreate this technique, and eventual chemical testing of the newly manufactured bikini glass, and a comparison of this to historic glass.

A series of visits to Bida were made by Lesley Lababidi between 2015 and 2019. During this time she spoke to Masagá elder Alhaji Abdulazeez Yanko, the only person who could be found who remembered observing the manufacture of Bikini glass. Alhaji Abdulazeez Yanko recalled that this last happened during the reign of Muhammadu Bakudu Ndayako, who was Estu (king) of Bida between 1935 and 1962. 

Lababidi also carried out interviews with traditional rulers of the Masagá glassmakers’ community, executives of the Masagá Glassmakers Cooperative Society, craftsmen, religious leaders, and others involved in the glassmaking process. Work on reconstructing the processes used by Masagá glassmakers to produce Bikini glass and analysis of historic glass samples to determine their constituents, both of which could potentially be seen as infringing on the secrets of their community, were carried out with the express permission of the current Etsu, His Royal Highness Alhaji (Dr.) Yahaya Abubakar, CFR. Some of the data collected during this process has been edited to make a documentary, The Lost Legacy of Bida Bikini, which can be viewed here.

Both forms of glass produced by the Masagá, bikini and kwálaba, are made in a workshop called an estwa, which is traditionally found at the entrance to each household of a family belonging to the community. There are currently only seven of these estwas remaining, although interviews produced the claim that there were ninety nine such estwas in Bini in the early twentieth century (although Lababidi et al. caution that this might be a symbolic number rather than an exact count). Each estwa was a circular, mud-built structure 3-3.5 m in diameter and about 6 m high, with three doors and several triangular ventilation holes. The furnaces within the estwas can be used for primary glass production or secondary manufacture of glass items, although it is possible that historically, when the number of estwas was larger, that some specialised in primary production and others in secondary manufacture.

The process of primary glass manufacture requires the combination of a number of different materials in the correct proportions, and the available manpower to keep a set of bellows running 24-hours-per-day. Masagá glassmaking is carried out in a furnace called an enaa within the estwa workshop. This is constructed within a pit dug for the purpose, with the sand excavated during this process serving as a raw material for glassmaking. This pit is lined with a type of red clay known as agun zuru, which is gathered from the River Chanchanga (a tributary of the River Kaduna, which in turn flows into the Niger), considered to be very resilient to high temperatures. The location of the source of this clay is not close to Bina, with the material being shipped in by boat.

The pit of an enaa is 40-100 cm in depth, and covered by a dome approximately 74 cm high, with the diameter of the dome corresponding to that of the pit. The dome has an opening at the top through which smoke escapes, and through which firewood, raw materials, and an iron rod used to test the glass are inserted. There is a second opening at the base of the dome, through which the bellows are inserted. Once constructed, the furnace is given a day to dry, then heated by inserting firewood, igniting this fuel, then pumping air in using the bellows. Any cracks which appear at this stage are patched by the addition of new clay.

Schematic diagram of the profile (a) and aerial view (b) of the bikini furnace. Lababidi et al. (2022).

The bellows, known as gurru, are of a the bowl bellows type common in West Africa, in which a pair of clay pots with leather coverings are used, with the leather covering of each being attached to a stick used to pump it up and down vertically. In this case the material used to make the pots is a white clay sourced from Maiduguri, roughly 838 km to the northeast of Bida, while the covering is made from goatskin leather, generally produced in Sokoto in the northwest of Nigeria. The traditional bikini making process is reported to have involved eight bellows-operators, each working a three-hour shift each day, sitting on a low bench and pumping the bellows, to give a 24 hour cover. Lababidi et al.'s research suggested that the bikini glassmaking process typically requires about five days of pumping time.

Bikini furnace for production of raw glass, with bellows, bellows operator, and the worker who inserts firewood. Lababidi et al. (2022).

The firewood used is of a type known as sanche, which grows beside the banks of the rivers Niger and Kaduna close to Bida. This is a red coloured wood reputed to retain march gasses, which burns smoothly, giving a steady heat throughout the glassmaking process. Charcoal is never used.

Lababidi et al. used local sand from Bida in their reconstruction. This is a red silica sand with a high iron oxide and alumina content, which may account for the black colour of bikini glass. This was mixed with soda, ash and water to form the glass. Soda and potash can be sourced from the area around Lake Chad, from Sokoto, or from Kano, but the Masagá were unwilling to provide exact details of the source they used. 

The subject of materials used appears to have been a sensitive one in general for the Masagá, who used terms for things included in the glassmaking process interchangeably during interviews, implying that they were either unable to distinguish between materials such as potash, clay and sand (unlikely), or that they were reluctant to discuss such matters with outsiders. Fred Nadel also recorded this reluctance to discuss materials being used by the Masagá, but also observed that sodium carbonate rather than potash was used as a fluxing agent, something which was supported by the chemical analysis of bikini glass carried out by Lababidi et al.

Based upon this analysis, plus the re-enactment of the process carried out by Lababidi et al., they conclude that the first step involved in the creating of bikini glass is the mixing of local sand, clay, sodium carbonate, and firegang (material recovered from previous firings of the furnace, called 'tswanbi' in Nupe), which are then pounded to an even constituency using a large pestle and mortar. This material is sieved to remove any large pieces, then mixed with water to form a paste, which is shaped into bricks resembling loaves of bread, which are dropped through the entrance at the top of the heated furnace. The furnace is kept hot for a further five days, with the consistency of the glass being periodically checked by scooping out samples with a L-shaped blade attached to an iron rod; it is considered to be complete when this blade is covered by a reddish glaze that hardens as it cools. Once this stage has been reached, heating of the furnace is ceased and it is allowed to cool for 3-5 days, before being dismantled to retrieve the finished glass.

Raw bikini glass (a) and tswanbi (b). Lababidi et al. (2022).

During secondary glassworking, the bikini is typically mixed with recycled glass (kwálaba), to produce objects such as beads or bangles. This can be done in the same furnace as the glassmaking, but is more generally accomplished in a cylindrical furnace, 50-55 cm high, constructed from local red clay on the workshop floor without a pit. This furnace is again fed through the a hole at the top, this whole being square in shape, with an indentation at each corner which can be used to support an iron rod.

Profile (a) and aerial view (b) of the Masaga glass working furnace. Lababidi et al. (2022).

The jewellery furnace is run at a lower temperature than the glassmaking furnace, and fuelled with small branches rather than the larger logs used in the latter. This furnace is often used by several glassworkers at the same time, often with each making different products. Individual glassmakers specialise in the making of a particular product, such as beads or bangles, but will be able to make that item in a variety of sizes and colours, in response to the needs of customers.

The Masagá secondary glass working furnace from Bida, Nigeria. Lababidi et al. (2022).

The most common, and distinctive, item produced by the Masagá glassworkers is the glass bracelet. These are made in single piece with no seams, and have a flat shape, often including ellipse-shaped air bubbles. These bracelets bear a remarkable similarity to those made by the Celtic La Tène culture, which flourished in central Europe from about 450 BC, until the area was taken over by the Roman Empire, which had its own, distinctive glassworking techniques. 

Fragments of bikini bracelets made during the reenactment. Lababidi et al. (2022).

Lababidi et al.'s reconstruction of the bikini glassmaking process has provided insights into how this process was accomplished, although much about the process remains mysterious. The exact materials and used and their proportions are unclear, and this is clearly something the Masagá glassmakers are deeply reluctant to discuss.

In order to address this gap in their knowledge, Lababidi et al. carried out a variety of chemical analysis tests on samples of Bikini glass at the Université d’Orléans. The samples analysed, including several beads and a sample of cullet (unworked glass), were donated by a Masagá glassmaker from his personal collection, and are thought to have originated from the last batch of bikini made in the 1960s. The tests were also carried out on glass from Lababidi et al.'s reconstructed glass, to give a point of reference.

Lababidi et al.'s tests suggest that bikini is a soda lime-silica glass, containing approximately 11.9–16.3% sodium oxide, 5.23–7.34% calcium oxide, plus small amounts of magnesia, potash, and phosphorus, and  fairly high amounts of alumina, iron, and titanium oxides. The composition of the beads was more variable than that of the cullet, suggesting that varying proportions of kwálaba (recycled glass) had been introduced to produce beads of different colours. 

The proportion of strontium to calcium can vary within a single bead, suggesting that the process by which the beads was made involves softening the glass to enable it to be worked, rather than completely melted. 

Lababidi et al. also analysed a greenish glaze which formed on the inside of the furnace. Unlike the bikini, this appeared to be a potash glass, which they believe formed from a reaction between potash derived from the wood burned in the furnace and minerals in the clay from which the furnace was constructed.

The production of seamless glass bracelets by the La Tène Celts is an ancient craft, long lost in Europe. The manufacture of similar bracelets by the modern Masagá glassmakers of Nupeland has the potential to shed light upon this lost craft. At the time when this craft was developed in Europe, glass-blowing had not been developed, and while glassmaking was practised in Greece, Egypt, and the Near East, this was largely confined to the making of beads. The craft of the La Tène glassmakers was refined over the centuries in which it was practised, with new decorative techniques being developed, and new materials, imported from Egypt and the Levant, being incorporated. This craft disappeared with the rise of the Roman Empire, which brought with it a the new technology of glass-blowing. Glass bracelets are still occasionally made in Europe to this day, but invariably with seams produced by soldering the glass; the ancient craft has been completely lost.

The comparison between the ancient La Tène bracelets and those produced by modern Masagá glassworkers was first made by the German archaeologist Théa Elisabeth Haevernick in the 1960s, who subsequently worked with René Gardi, the Swiss travel writer, who filmed the Masagá glassworking process, with the specific intention of comparing it to the lost La Tène craft. 

The process by which seamless glass bracelets are made is very different from modern European glassworking traditions based around glass-blowing technologies, and subsequently very difficult for glassworkers trained in that tradition to master. 

Bikini glass is known to have been manufatured in Bida since at least the mid-nineteenth century. However, this is long after the appearance of European glass in the area, and has no archaeological record within the city, requiring the development of a typification process to understand the history of the industry. Doing this has the potential to shed light on the history of the Masagá glassworkers, but the wider indigenous glassmaking history of sub-Saharan Africa.

The closest site to Bida where glassmaking does have an archaeological history is the Yoruba city of Ile-Ife in southwest Nigeria. Archaeological excavations at the  Igbo-Olokun site in Ile-Ife have revealed evidence of glassworking going back to the eleventh century, but how this relates to the modern glass industry of Bida is unclear. The breaking up of the furnace used by Lababidi et al. to produce their Bikini glass revealed that the inside of the furnace had become covered by a greenish glaze, which when the furnace was broken open produced distinctive concave fragments. Similar fragments have been recovered from the  Igbo-Olokun archaeological site, suggesting that a similar glassmaking process may have been used here. Similar fragments have been found at Ayelabowo, another ancient glass workshop excavated at Ile-Ife, but not at other archaeological sites within the city. The origin of these fragments has until been unclear, and they have simply been referred to as 'vitrified production debris'. Lababidi et al.'s work suggests that these fragments were in fact the remains of furnaces similar to those used by the modern Masagá glassmakers.

Glass-making furnace remains. (a) Fragments from Igbo-Olokun, Ile-Ife. (b) Fragments from the reproduction at Bida. Lababidi et al. (2022).

Chemical analysis of the furnace remains from Bida and presumed furnace remains from Igbo-Olokun produced similar results, with both apparently being glazes formed by the chemical interaction of the potash from burned wood with minerals from a clay furnace. This suggests that a similar technology was used at both sites, probably with the destruction of the furnace at the end of each glassmaking process, although some of the Igbo-Olokun material does appear to show a higher layer of vitrification, with ash trapped between layers of glaze, possibly indicating re-use of the furnace.

Several circular pits were excavated at Ile-Ife, including three conjoined pits of different depths, with the deepest being about 1 m deep and the shallowest about 40 cm. These pits have previously been thought to be associated with the glassmaking process, but evidence as to how has been lacking. The similarity between these pits and the one produced by the Bida glassmaking reconstruction provides support for this hypothesis.

It was charcoal from the bottom of the shallowest pit that yielded the eleventh century date, the oldest date yielded from the site, and therefore the oldest date at which glassmaking in the city can be confidently asserted, although there are other known pits at the site which have not been completely excavated yet, as well as the potential to uncover new pits as excavations continue, so it is possible that earlier evidence may be found in the future. 

These pits are different from structures associated with the glassmaking industry elsewhere in the world, such as the large workshops of South Asia, or the tank-furnaces of the Levant, and it is possible that similar structures elsewhere in sub-Saharan Africa have been overlooked, and that re-examination of old archaeological reports may produce evidence of more widespread African glassmaking.

The possible transfer of a glassmaking technology between Ile-Ife and Bida raises some interesting questions. Traditionally, the Masagá have been considered to have migrated from Egypt in the eighteenth century, something they themselves believe. This is a narrative commonly encountered in sub-Saharan African history; that technologies have not been developed locally, but introduced by travellers from North Africa, the wider Mediterranean region, or even Europe. However, there is no actual evidence to support this, and the glassmaking technology of Bida is quite different from anything practised in Egypt. 

The Nupe and the Yoruba are neighbouring communities with long a long history of interaction, and many shared cultural traits and technologies. In the eleventh-to-twelfth centuries many craftsmen from the wider Yoruba community, as well as neighbouring communities, were recruited to Ile-Ife, some of whom stayed, while others returned to their homes, often taking with them new skills. It is quite possible that glassmaking was introduced to Nupeland at this time, although in the absence of of any archaeological evidence this is an untestable hypothesis, and all that can be asserted is a similarity between modern glassmaking in Bida and the archaeological evidence from Ile-Ife.

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Sunday, 23 October 2022

Partial Solar Eclipse to be visible from Europe, the Middle East, and parts of Africa and Asia.

A partial Solar Eclipse will occur on Tuesday 25 October 2022, which will be visible from all of Europe apart from Portugal and much of Spain, as well as the Middle East, Egypt Djibouti, much of Libya, Sudan, Ethiopia, Somalia, western parts of Russia, Central Asia, Afghanistan, and Pakistan. Part of the eclipse will also be visible from Greenland, parts of Russia, the rest of Central and South Asia, western China and Mongolia, where the Sun will either rise or set part way through the eclipse. The event will occur between 8.52 am and 1.02 pm GMT.

The area over which the 5-6 January partial Solar Eclipse will be visible. Areas in darker grey will be able to observe the entire eclipse; in the lighters area the full eclipse will not be visible as it will have started before dawn (west) or will continue after sunset (east). The solid red lines are the Equator and the International Date Line, the dashed red lines are the Tropic of Cancer and Tropic of Capricorn. HMNautical Almanac Office.

Eclipses are a product of the way the Earth, Moon and Sun move about one-another. The Moon orbits the Earth every 28 days, while the Earth orbits the Sun every 365 days, and because the two Sun and Moon appear roughly the same size when seen from Earth, it is quite possible for the Moon to block out the light of the Sun. At first sight this would seem likely to happen every month at the New Moon, when the Moon is on the same side of the Earth as the Sun, and therefore invisible (the Moon produced no light of its own, when we see the Moon we are seeing reflected sunlight, but this can only happen when we can see parts of the Moon illuminated by the Sun).

The relative positions of the Sun, Moon and Earth during a Solar eclipse. Starry Night.

However the Moon does not orbit in quite the same plane as the Earth orbits the Sun, so the Eclipses only occur when the two orbital planes cross one-another; this typically happens two or three times a year, and always at the New Moon. During Total Eclipses the Moon entirely blocks the light of the Sun, however most Eclipses are Partial, the Moon only partially blocks the light of the Sun.

How the differing inclinations of the Earth and Moon's orbits prevent us having an eclipse every 28 days. Starry Skies.

Although the light of the Sun is reduced during an Eclipse, it is still extremely dangerous to look directly at the Sun, and an eclipse should always be viewed using appropriate equipment. 

Animation showing the shadow of the Moon at five minute intervals on 25 October 2022. Andrew Sinclair/HM Nautical Almanac.

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Menisporopsis aquatica: A new species of freshwater Fungus from Zhejiang Province, China.

Although generally thought of as terrestrial organisms, Fungi are an integral part of marine, freshwater, and wet terrestrial ecosystems, helping to break down dead organic tissue, and in particular wood. The genus Menisporopsis contains 13 species of marine and freshwater Ascomycote Fungi producing pigmented, synnematous conidiophores (cylindrical asexual spores). The genus was first described in 1952 to describe a Fungus found growing on rotting Cocoa leaves in Ghana.

In a paper published in the Biodiversity Data Journal on 21 October 2022, Jia-Hao Chen of Jiangxi Agricultural University, Dian-Ming Hu, also of Jiangxi Agricultural University, and of the Jiangxi Environmental Engineering Vocational College, and Hai-Yan Song, Zhi-Jun Zhai, Lin La, and Kang-Hui Lin, also of Jiangxi Agricultural University, describe a new species of Menisporopsis found growing on submerged wood in a brook in Zhejiang Province, China.

The new species was established as such using a molecular phylogeny based upon  a combined two-loci dataset, including the internal transcribed spacer sequences and the nuclear ribosomal large subunit gene sequences. This found the new species to be nested within the Menisporopsis clade, forming a sister group to the branch comprising Menisporopsis breviseta and Menisporopsis pandanicola, with Menisporopsis dushanensis forming the sister group to all three of these species. Having been established as a new species, the Fungus was named Menisporopsis aquatica in reference to its freshwater habitat.

Phylogenetic tree obtained from the DNA sequence data of internal transcribed spacer sequences and ribosomal large subunit sequences of 32 strains showing taxa in Menisporopsis and Dictyochaeta. The new isolates are shown in bold, red. The bootstrap values (greater than 75%) and Bayesian posterior probabilities (greater than 95%) are presented at the nodes. The scale bar shows the number of estimated mutations per site. The tree was rooted to Leptosporella arengae (MFLUCC 15-0330) and Leptosporella bambusae (MFLUCC 12-0846). Chen et al. (2022).

Menisporopsis aquatica was found growing on submerged wood in the Qianjia Lou Brook near the town of Daoxu in Shangyu District. The Fungus forms a pale yellow to pale brown branching mycelium. It produces black setae, which are surrounded by tightly packed brown conidiophores. 

Menisporopsis aquatica (HFJAU 10038, Holotype) (a)-(b) conidiophores and conidia on submerged wood; (c) conidiophores with seta; (d) apex of the conidiophore with developing conidia; (e) base of the conidiophore; (f) seta; (g)-(j) conidia; (k) colony on Potato dextrose agar. Scale bars: (a)-(b), 100 µm; (c), 50 µm; (d)-(j), 10 µm. Chen et al. (2022).

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Saturday, 22 October 2022

Magnitude 6.7 Earthquake to the south of Panama.

The United States Geological Survey recorded a Magnitude 6.7 Earthquake at a depth of 10.0 km, about 62 km off the south coast of Chiriquí Province on the Pacific Coast of Panama, slightly before 7.00 am local time (slightly before midday GMT) on Thursday 20 October 2022. There are no reports of any damage or casualties associated with this event, though it was felt across much of Panama and Costa Rica.

The approximate location of the 20 October 2022 Pananma Earthquake. USGS.

Panama lies on a tectonic microplate known as the Panama Plate or Panama Block, which has broken away from the North American Plate within the last 20 million years, and is now caught between the Caribbean, Cocos, Nazca and South American Plates. The southern margin of this is both a convergent and a transform margin, as the Nazca Plate moves past the Panama plate in a westerly direction, but is also being partially subducted beneath Panama. This is not a smooth process; the two plates continually stick together, then break apart once the pressure builds up sufficiently, causing Earthquakes in the process.

The tectonic plates underlying Central America and the surrounding areas. Wikimedia Commons.

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