Comet C/2021 E3 (ZTF) comes to perihelion.

Comet C/2021 E3 (ZTF) will teach its perihelion (the closest point on its orbit to the Sun) slightly after 10.05 pm GMT on Saturday 11 June 2022, when it will be approximately 1.78 AU from the Sun (i.e. 1.78 times as far from the Sun as the planet Earth, or 265 895 500 km). At this time the comet will be 1.26 AU from the Earth, in the constellation of Mensa (close to the South Celestial Pole and better observed from the Southern Hemisphere), having a magnitude of 12.4, making it visible with a reasonable telescope, although it will not be visible from much of the Northern Hemisphere.

Comet C/2021 E3 (ZTF) seen from Kruibeke in Belgium on 17 April 2022. Composite image made up from three 120 second exposures. BREXIIS Observatory. 

C/2021 E3 (ZTF) was discovered on 2 March 2021 by the Zwicky Transient Facility at Palomar Observatory in California. The name  C/2021 E3 (ZTF) implies that it is a comet (C/), that it was the third comet like body (comet ) discovered in the first half of March 2021 (period 2021 E) and that it was discovered by the Zwicky Transient Facility.

The trajectory of Comet C/2021 E3 (ZTF), and its current position. JPL Small Body Database.

Comet C/2021 E3 (ZTF) is a Parabolic Comet, which is to say a comet that was disrupted from an orbit in the Oort Cloud, and is passing through the Inner Solar System on a parabolic orbit that will probably not bring it back again. This parabolic trajectory tilted at an angle of 113° to the plain of the Solar System, that will bring it in to 1.78 AU from the Sun at perihelion on 11 June 2022, between the orbits of the planets Mars and Jupiter.

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Chelydropsis aubasi: A new species of Snapping Turtle from the Middle Eocene of France.

Snapping Turtles, Chelydridae, form an important part of modern North American freshwater ecosystems, but have a relatively poor fossil record, largely because their shells are relatively thin compared to other Turtle groups, and tend to disarticulate rapidly after death. However, the fossil record we do have suggests that the group originated in North America in the Late Cretaceous, with subsequent dispersals into Europe and Asia (where they arrived in the Oligocene or earlier and became locally extinct in the Pliocene) and South America (where they arrived in the Pleistocene or earlier, and are still present). 

The dispersal patterns of Snapping Turtles appear to have been different from those of other Turtle groups. The European Turtle fauna of the Cretaceous and Palaeocene comprised indigenous lineages of Thremydids, Helochelydrids, and Pleurosternids, with occasional influxes from elsewhere. This indigenous Turtle population disappeared around the time of the Palaeocene-Eocene Thermal Maximum, and was subsequently replaced by a new fauna including Carettochelyids, Pan-geoemydids, Pan-testudinids, Podocnemidids, and Trionychids. All of these Turtles are present in Asia, which led palaeontologists the theorise that this new influx came entirely from that continent, but more recent studies have suggested that some European groups, most notably the Trionychids, appear to be more closely related to North American faunas than to those of Asia, possibly implying a dispersal into Europe via Greenland. Snapping Turtles appeared to have arrived in Europe much later, with the Earliest known examples from the Late Oligocene, suggesting an arrival into Europe quite separate from the Palaeocene-Eocene Thermal Maximum, and its immediate after-effects. There have been reports of older Snapping Turtle remains from the Eocene of France, although none of this material has ever been formally described.

In a paper published in the journal The Anatomical Record on 6 June 2022, Walter Joyce of the Department of Geosciences at the University of Fribourg, Jean-Luc Landréat of Soissons in France, and Yann Rollot, also of the Department of Geosciences at the University of Fribourg, describe a Snapping Turtle from the Middle Eocene deposits of the Chéry-Chartreuve Sandpit in the Department of Aisne, France.

The Chéry-Chartreuve Sandpit lies half way between the towns of Soissons and Reims, and contained sediments laid down in a transition from a marine to a continental setting. The pit was worked as a quarry in the 1990s and 2000s, exposing a fosiliferous layer at the base of the sequence, from which numerous fossils were extracted by Pierre Louis, Maurice Sabatier, and Jean-Luc Landréat, with the blessing of the quarries' owner, Charles Aubas. An area of about 10 000 m² of the fossil-bearing layer was exposed during this process, the whole of which was removed. This produced an extensive Vertebrate fossil fauna, including Birds, Crocodilians, Fish, Mammals, and Turtles, the majority of which are very well preserved, with little or no crushing or diagenetic darkening. Relatively little of this assemblage has been described to date. The precise age of this deposit has not yet been determined, but it is probably Bartonian (Middle Eocene or between 42.1 and 37.71 million years old.

A simplified map of France highlighting the location of the middle Eocene locality of Chéry-Chartreuve in the Departmentof Aisne. All departments previously reported to have yielded Pan-chelydrid remains, all of which are Oligocene, are highlighted in orange. Joyce et al. (2022).

The Snapping Turtle is placed in the genus Chelydropsis, and given the specific name aubasi, in honour of the late Charles Aubas, who owned the Chéry-Chartreuve Sandpit quarry and both permitted and supported the activities of palaeontologists there. This species is described from a collection of shell elements including, a neural III and IV withpartial right costa, a right peripheral I, a right peripheral II, a right peripheral III, a left peripheral IV and V, a left peripheral VI, a left peripheral VII, a right peripheral VIII, a left peripheral XI, a left epiplastron, an entoplastron, a left hyoplastron a partial right hyoplastron, a partial left hypoplastron, the lateral portion of a right hypoplastron, and , a partial left xiphiplastron. 

Chelydropsis aubasi, Middle Eocene (MP15, early Bartonian) of Chéry-Chartreuve, Aisne, France. 3D models of select costals and neurals. (a) NMB CHC.33, a neural II; (b) NMB CHC.465, a neural II; (c) NMB CHC.3, a neural III and IV with partialright costal IV; (d) NMB CHC.157, a neural IV; (e) NMB CHC.431, two fused posterior neurals; (f) NMB CHC.156, a posterior neural; (g) NMB CHC.34, a posterior neural; (h) NMB CHC.155, a posterior neural; (i) NMB CHC.154, a posterior neural; (j) NMB CHC.158, aposterior neural; (k) NMB CHC.466, medial portion of a left costal II; (l) NMB CHC.32, medial portion of a right costal IV; (m) NMBCHC.509, distal portion of a costal. Abbreviations: Co, costal; ne, neural; Ve, vertebral scute. Joyce et al. (2022).

Fossils of Snapping Turtles are often highly incomplete, and the Animals themselves can be morphologically variable within species, while different species are often very similar, making it difficult to differentiate species. This has led to a high level of confusion in the taxonomy of fossil Snapping Turtles. A total of fifteen extinct species have been proposed from European fossils to date, although Joyce et al. suggest that three might be a more reasonable number (some experts in the field go as low as two), these being Chelydropsis decheni, found in deposits dating from the Late Eocene to the Middle Miocene, Chelydropsis murchisoni, dating from the Middle Miocene and Chelydropsis ponitica, from the Late Miocene to Early Pliocene.

Chelydropsis aubasi, middle Eocene (MP15, early Bartonian) of Chéry-Chartreuve, Aisne, France. 3D models of allavailable peripherals in standard views. Left elements are flipped along the long-axes to ease comparison with right elements. (a) NMB CHC.15, a right peripheral I; (b) NMB CHC.13, a right peripheral II; (c) NMB CHC.27, a right peripheral III; (d) NMB CHC.23, a left peripheral IV;(e) NMB CHC.23, a partial left peripheral V; (f) NMB CHC.26, a left peripheral VI; (g) NMB CHC.4, a left peripheral VII; (h) NMB CHC.28, aright peripheral VIII; (i) NMB CHC.19, a left peripheral XI. Abbreviations: Ab-f, axillary buttress facet; cr-f, costal rib facet; hyo-f, hyoplastralfacet; hyp-f, hypoplastral facet; ib-f, inguinal buttress facet; ma, marginal scute; nu-f, nuchal facet; Pl, pleural scute; Ve, vertebral scute. Joyce et al. (2022)

The new species, Chelydropsis aubasi, does show some resemblance to Chelydropsis decheni, the earliest known species, but Joyce et al. feel that the differences that it does posses, combined with the chronological separation from all known specimens of that species, warrants its description as a new species.

Chelydropsis aubasi, middle Eocene (MP15, early Bartonian) of Chéry-Chartreuve, Aisne, France. Photograph and interpretive line drawings of plastral elements in (a) ventral and (b) dorsal view, including NMB CHC.2 (a left epiplastron), NMB CHC.1(an entoplastron), NMB CHC.198 (a left hyoplastron), NMB CHC.199 (a partial right hyoplastron), NMB CHC.66 (a partial left hypoplastron), NMB CHC.505 (the lateral portion of a right hypoplastron), NMB CHC.251 (a partial left xiphiplastron). Abbreviations: Ab, abdominal scute; an, anal scute; ent, entoplastron; epi, epiplastron; Fe, femoral scute; Gu, gular scute; Hu, humeral scute; hyo, hyoplastron; hyp, hypoplastron; IG, intergular scute; IM, inframarginal scute; xi, xiphiplastron. Joyce et al. (2022).

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The Daytime Arietid Meteor Shower.

The Arietid Meteor Shower lasts from late May to early July each year, and is expected to peak before dawn on Saturday 11 June this year, and originating (appearing to come from) the constellation of Aries. Meteors from this shower can be very bright, leading to the label 'Daytime' Meteors (i.e. meteors that can be seen during the day), although the majority are quite dim, and can be hard to spot. At its peak, the shower can produce about 50 meteors per hour, although this year that peak will fall only three days before the full moon, which will interfere with visibility and make the meteors harder to spot.

The origin point for the Aried Meteors seen from the Northern Hemisphere in early June. Spaceweather.

Meteor streams are thought to come from dust shed by comets as they come close to the Sun and their icy surfaces begin to evaporate away. Although the dust is separated from the comet, it continues to orbit the Sun on roughly the same orbital path, creating a visible meteor shower when the Earth crosses that path, and flecks of dust burn in the upper atmosphere, due to friction with the atmosphere.

The Earth passing through a stream of comet dust, resulting in a meteor shower. Not to scale. Astro Bob.

The origin of the Arietid Meteors is unclear. No body has been confidently identified as the source of the Arietid Meteors, though both the asteroid 1566 Icarus and the comet 96P/Machholz have been suggested. 

How the passage of the Earth through a meteor shower creates a radiant point from which they can be observed. In The Sky.

Though the Arietid  Meteors are hard to see, it may be possible to 'hear' them using an FM radio. In order to do this it will be necessary to find a frequency between 88.0 and 108.0 MHz without any transmissions or significant static (this may not be possible in urban areas). Meteors passing though the atmosphere generate radio waves at these frequencies, which can be heard as 'bumps' or 'chirps'. More detailed observations can be used if the radio set-up has a directional antenna, allowing the observer to concentrate on a particular part of the sky (this is essentially what a radio telescope is).

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Thirteen confirmed deaths and fourteen suspected in an outbreak of Crimean-Congo Haemorrhagic Fever in Iraq.

Between 1 January to 22 May 2022, the health authorities of the Republic of Iraq notified World Health Organization of 212 cases of Crimean-Congo Hemorrhagic Fever, of which 115 (54%) were suspected and 97 (46%) laboratory-confirmed; there were 27 deaths, 14 in suspected cases and 13 in laboratory confirmed cases, according to a Press Release issued on 1 June 2022. The number of cases reported in the first five months of 2022 is much higher than that reported in 2021, when 33 laboratory confirmed cases were recorded. Cases have been reported in several areas (governorates) in Iraq and the outbreak may pose additional pressure to an already over-stretched health care system.

Between 1 January and 22 May 2022, 212 cases of Crimean-Congo Hemorrhagic Fever have been reported to the World Health Organization from the Iraqi health authorities of which 169 (80%) were reported in April and May alone. Of the 212 cases, 115 were suspected and 97 laboratory confirmed.  Twenty seven deaths occurred overall, of which 13 were in laboratory confirmed cases.

The Iraq Central Public Health Laboratory confirmed the cases by polymerase chain reaction. Among confirmed cases, most had direct contact with animals, and were livestock breeders or butchers. Just over half of the confirmed cases were 15 to 44 years old (52, or 54% of the total number of reported cases) and of male gender (60, or 62% of the total number of reported cases).

Nearly 50% of confirmed cases (47, or 48% of the total number of reported cases) were reported in Thiqar Governorate, southeast Iraq, and the remainder of cases were reported from 12 different governorates; Missan (13), Muthanna (7), Wassit (6), Diwaniya (4), Baghdad Karkh (4), Kirkuk (3), Basrah (3), Najaf (3), Nineveh (3), Baghdad-Rusafa (2), Babylon (1) and Karbala (1).

Distribution of laboratory confirmed cases of Crimean-Congo Hemorrhagic Fever by governorate, Iraq, 1 January to 22 May 2022. World Health Organization.

Crimean-Congo Haemorrhagic Fever is a viral haemorrhagic fever usually transmitted by ticks. It can also be contracted through contact with viraemic animal tissues (animal tissue where the virus has entered the bloodstream) during and immediately post-slaughter of animals. Crimean-Congo Haemorrhagic Fever outbreaks constitute a threat to public health services as the virus can lead to epidemics, has a high case fatality ratio (10-40%), potentially results in hospital and health facility outbreaks, and is difficult to prevent and treat. Crimean-Congo Haemorrhagic Fever is endemic in all of Africa, the Balkans, the Middle East and in Asia. 

The disease was first described in the Crimea in 1944 and given the name Crimean Haemorrhagic Fever. In 1969 it was recognised that the pathogen causing Crimean Haemorrhagic Fever was the same as that responsible for an illness identified in 1956 in the Congo. The linkage of the two place names resulted in the current name for the disease and the virus.

Crimean-Congo Haemorrhagic Fever is caused by the Crimean-Congo Haemorrhagic Fever Orthonairovirus, a negative-sense single-strand RNA Virus closely related to the Viruses that cause Dugbe Fever, Nairobi Sheep Disease, and Kasokero Fever. It is spread principally by Hard-bodied Ticks of the genus Hyalomma. These Ticks are not generally found north of the 50th Parallel North, providing a limit on the spread of the disease, although it is possible that a warming climate could lead to the Ticks and the Virus spreading further north.

The hosts of the Crimean-Congo Haemorrhagic Fever Virus include a wide range of wild and domestic Animals such as Cattle, Sheep and Goats. Many Birds are resistant to infection, but Ostriches are susceptible and may show a high prevalence of infection in endemic areas, where they have been at the origin of Human cases. For example, a former outbreak occurred at an Ostrich abattoir in South Africa. There has also been at least one reported case of a person becoming infected with Crimean-Congo Haemorrhagic Fever from a Tick carried on a migrating Bird.

Animals become infected by the bite of infected Ticks and the Virus remains in their bloodstream for about one week after infection, allowing the Tick-Animal-tick cycle to continue when another Tick bites. Although a number of tick genera are capable of becoming infected with Crimean-Congo Haemorrhagic Fever Virus, Ticks of the genus Hyalomma are the principal vector.

The Crimean-Congo Haemorrhagic Fever Virus is transmitted to people either by Tick bites or through contact with infected Animal blood or tissues during and immediately after slaughter. The majority of cases have occurred in people involved in the livestock industry, such as agricultural workers, slaughterhouse workers and veterinarians.

Human-to-Human transmission can occur resulting from close contact with the blood, secretions, organs or other bodily fluids of infected persons. Hospital-acquired infections can also occur due to improper sterilisation of medical equipment, reuse of needles and contamination of medical supplies.

The length of the incubation period depends on the mode of acquisition of the Virus. Following infection by a Tick bite, the incubation period is usually one to three days, with a maximum of nine days. The incubation period following contact with infected blood or tissues is usually five to six days, with a documented maximum of 13 days.

Onset of symptoms is sudden, with fever, myalgia, (muscle ache), dizziness, neck pain and stiffness, backache, headache, sore eyes and photophobia (sensitivity to light). There may be nausea, vomiting, diarrhoea, abdominal pain and sore throat early on, followed by sharp mood swings and confusion. After two to four days, the agitation may be replaced by sleepiness, depression and lassitude, and the abdominal pain may localise to the upper right quadrant, with detectable hepatomegaly (liver enlargement).

Other clinical signs include tachycardia (fast heart rate), lymphadenopathy (enlarged lymph nodes), and a petechial rash (a rash caused by bleeding into the skin) on internal mucosal surfaces, such as in the mouth and throat, and on the skin. The petechiae may give way to larger rashes called ecchymoses, and other haemorrhagic phenomena. There is usually evidence of hepatitis, and severely ill patients may experience rapid kidney deterioration, sudden liver failure or pulmonary failure after the fifth day of illness.

The mortality rate from Crimean-Congo Haemorrhagic Fever is approximately 30%, with death occurring in the second week of illness. In patients who recover, improvement generally begins on the ninth or tenth day after the onset of illness. Patients with fatal disease, as well as in patients in the first few days of illness, do not usually develop a measurable antibody response and so diagnosis in these individuals is achieved by Virus or RNA detection in blood or tissue samples. Tests on patient samples present an extreme biohazard risk and should only be conducted under maximum biological containment conditions. However, if samples have been inactivated (e.g. with virucides, gamma rays, formaldehyde, heat, etc.), they can be manipulated in a basic biosafety environment.

It is difficult to prevent or control Crimean-Congo Haemorrhagic Fever infection in Animals and Ticks as the Tick-Animal-Tick cycle usually goes unnoticed and the infection in domestic Animals is usually not apparent. Furthermore, the tick vectors are numerous and widespread, so Tick control with acaricides (chemicals intended to kill Ticks) is only a realistic option for well-managed livestock production facilities.

Human cases of Crimean-Congo Haemorrhagic Fever are mainly treated with general supportive care. The antiviral drug Ribavirin, both oral and intravenous formulations, has been used to treat Crimean-Congo Haemorrhagic Fever infection. However, no evidence from randomised clinical trials has demonstrated the effectiveness of Ribavirin for treating Crimean-Congo Haemorrhagic Fever. There is currently no vaccine available for either people or Animals.

In the absence of a vaccine, the only way to reduce infection in people is by raising awareness of the risk factors and educating people about the measures they can take to reduce exposure to the Virus.

In Iraq Crimean-Congo Haemorrhagic Fever has been reported in Iraq since 1979 when the disease was first diagnosed in ten patients. Since then, six cases were reported between 1989 and 2009; 11 cases in 2010; three fatal cases were reported in 2018; and more recently 33 confirmed cases including 13 deaths (a mortality rate of 39%) were reported in 2021.

Sheep and Cattle husbandry are very common in Iraq. Studies have shown that these Animals are regularly infested with Ticks, mainly Hylomma species, the principal vector of Crimean-Congo Haemorrhagic Fever.

Thiqar Governorate is divided into rural (42% of the governorate) and urban (58%) areas, where livestock farming of Sheep, Goats, Cattle, Camels, and Buffalo is an important source of livelihood, especially for the rural population. Subsistance farming is common in villages where Animal barns are located near houses and all family members take care of domestic Animals. In these settings, Crimean-Congo Haemorrhagic Fever may be transmitted from domestic Animals to Humans.

There is an increased risk of further spread of Crimean-Congo Haemorrhagic Fever within Iraq due to the upcoming religious holiday, Eid al-Adha in July, because more Camels, Cows, and Sheep will be slaughtered during that period. Additionally, international cross-border transmission cannot be ruled out given the increased population movement and possible Animal exportation associated with the holiday. During Ramadan, which took place in March and April 2022, the number of Crimean-Congo Haemorrhagic Fever cases steadily increased, and the geographical spread of the disease expanded to more governorates.

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Eardasaurus powelli: A new Pliosaurid from England's Middle Jurassic Oxford Clay Formation.

The earliest known Pliosaurid Plesiosaurians date from rocks of the Earliest Jurassic. Long-snouted forms showing adaptations to for a specialist piscivoran diet appearing by the end of the Early Jurassic. Classical 'pliosauromorph' forms with large bodies, short necks, and heads which form a high proportion of the total body-length, appearing by the Middle Jurassic, and reaching sizes of 10-12 m by the Late Jurassic. This bodyform then remained essentially unchanged until the group disappeared in the early Late Cretaceous.

One of the most important deposits for the study of this group is the Oxford Clay Formation of England, which has been studied since the nineteenth century, and has produced a large and diverse assemblage of Plesiosaurs, with at least five valid described species: Simolestes vorax, Liopleurodon ferox, Peloneustes philarchus, 'Pliosaurus' andrewsi, and Marmornectes candrewi (a sixth, Pachycostasaurus dawni, is problematic, since it was described from a juvenile specimen that could potentially belong to several of the other species). Many of these are known from multiple specimens, notably Peloneustes philarchus, of which 21 examples have been found.

Many of these specimens, as well as other spectacular fossils from the same formation, were collected from pits which primarily extracted clay for the brick-making industry. The heyday of this industry was in the second half of the nineteenth century, when the brothers Charles and Alfred Leeds collected numerous Plesiosaur (and other) specimens from the clay pits around Peterborough in Cambridgeshire, including the holotypes of Simolestes vorax and 'Pliosaurus' andrewsi. The brick-making industry has declined greatly since this time, with a subsequent decline in the amount of activity at clay pits, and therefore the number of fossils recovered from them, but spectacular new finds are still reported from time to time, with the most recently described Oxford Clay Plisiosaur, Marmornectes candrewi, having been recovered from a clay pit in Bedfordshire in 1998.

In a paper published in the journal Acta Palaeontologica Polonica on 23 May 2022, Hilary Ketchum of the Oxford University Museum of Natural History, and Roger Benson of the Department of Earth Sciences at the University of Oxford, describe a new species of Pliosaurid from the Peterborough Member of the Oxford Formation, collected from the former ARC Cassington gravel pit near Yarnton, Oxfordshire.

The new Pliosaur is named Eardasaurus powelli, where 'Eardasaurus' is a combination of the  Old English 'eard', meaning 'native soil or dwelling', from which the village name Yarnton was derived, and '-saurus' the Greek for Lizard, commonly used as a suffix for large Mesozoic Animals, while 'powelli' honours Philip Powell, former Assistant Curator at the Oxford University Museum of Natural History, who took part in the excavation of the specimen from which the species is described in 1994, and carried out preparation work on its skull and postcranial skeleton.

The species is described from a single specimen, OUMNH PAL-J.2247, which was discovered during the construction of a deep silt pond. This specimen was partially embedded in six concretions, which enclosed the posterior two-thirds of the cranium, parts of the vertebral series, and the hindlimb.

Holotype of the Pliosaurid Plesiosaur Eardasaurus powelli (OUMNH PAL-J.2247) from the Middle Jurassic of Yarnton, Oxfordshire, UK. Photograph of the specimen on display in Oxford University Museum of Natural History. Skeleton laid out as discovered, with the exception of the left hindlimb (highlighted in black), which was originally disarticulated. An artist’s reconstruction of Eardasaurus powelli  is partially visible in the top right-hand side of the image. Ketchum & Benson (2022).

Specimen OUMNH PAL-J.2247  measures approximately 4.7 m long from the tip of the snout to the end of the (incomplete) tail, as preserved, and includes the cranium, lower jaw, four scleral ossicles, two hyoids, more than 40 teeth and tooth fragments (including both disarticulated and in situ teeth), atlas-axis complex, 57 postaxial vertebrae (comprising 18 cervicals, 3 pectorals, 24 dorsals, 4 sacrals, and 8 caudals, along with disarticulated neural arches, neural spines, ribs, and chevrons), and 11 gastralia. The preserved appendicular skeleton includes the distal end of the right humerus plus a partial left forelimb discovered in articulation, which includes the radius, ulna, proximal and distal carpals, and 17 phalanges. There is a partial left hindlimb compri sing the femur, proximal and distal tarsals. In total 40 complete phalanges, plus six partial phalanges were found disarticulated and cannot confidently be assigned to any particular limb. Of the limb girdles, only the interclavicle and a clavicle are preserved.

Eardasaurus powelli is a Longirostrine Pliosaurid with a high number (35-40) of alveoli on its maxilla, a jugal with fluted ornamentation on its orbital margin, a step-like contact between the jugal and the squamosal, a 'lacrimal' bone formed by the neomorphic ossification in the anteroventral orbit margin (and not homologous to the lacrimal of other Tetrapods) which is dorsoventrally slender with a posterior rod-like projection.

Eardasaurus powelli also has a pattern of enamel ridges on its larger (mesial) teeth, something also seen in Peloneustes philarchus, but absent in other Pliosaurids from the Oxford Clay. It also has five to six premaxillary teeth, a  prominent mediolateral constriction of the rostrum at the premaxilla–maxilla suture, a diastema (gap) between premaxillary and maxillary dentitions, a  maxilla excluded from contact with the medial margin of external naris by an anterior extension of the frontal, a proportionally elongate posterior interpterygoid vacuities compared to other Middle Jurassic Pliosaurids, a mediolaterally expanded mandibular symphysis, nine pairs of dentary teeth adjacent to the mandibular symphysis, a  splenial which encloses the posterior margin of the anterior opening of Meckel’s canal, and a coronoid exposed on the lateral surface of the mandible, a strongly convex medial expansion of the surangular in dorsal view.

Holotype of the Pliosaurid Pleasiosaur Eardasaurus powelli (OUMNH PAL-J.2247) from the Middle Jurassic of Yarnton, Oxfordshire, UK. Cranium in dorsal view. Photograph (A₁), interpretive drawing (A₂), light grey, broken bone; mid grey filler; dark grey, matrix. Ketchum & Benson (2022).

A phylogenetic analysis carried out by Ketchum and Benson recovered Eardasaurus powelli as an early-diverging Thalassophonean Pliosaurid, forming the sister taxon to the derived group comprising 'Pliosaurus' andrewsi, Simolestes vorax, Liopleurodon ferox, Pliosaurus spp., and Brachaucheninae.

Phylogenetic topology for Pliosauridae, focussing on Early–Middle Jurassic representatives, based on Bayesian Mkv analysis. Numbers indicate posterior support for nodes demonstrating strong support for many aspects, but weaker support for relationships among Peloneustes philarchus, Anguanax zignoi, and Eardasaurus powelli, which are tentatively recovered as grade leading to more derived Pliosaurids. Ketchum & Benson (2022).

Eardasaurus powelli has a pattern of deep ridges on its teeth which would have formed additional deep cutting surfaces in life. Such ridges are ecologically significant, as they are typically associated with macropradatory behaviour (i.e. attacking large prey). Such ridges are found in a range of taxa, although they are rare (but not unknown) in Pliosaurids, although Ketchum & Benson suggest that this may be due to under-reporting rather than a true absence.

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Large bolide impact detected on the surface of Jupiter.

Optical flashes caused by impact events on the surface of Jupiter have been within the detection capabilities of amateur astronomers for some time, with six such flashes reported between 2010 and 2020. These events have the potential to provide us with information about the abundance of small objects in the Outer Solar System, which are close to impossible to detect by direct observations, as well as the consequences of such impacts on planetary atmospheres, information which can be used to improve models of such impacts on Earth.

Models suggest that the majority of impacts on Jupiter are caused by Jupiter Family Comets (bodies with orbital periods of less than 20 years and relatively low orbital inclinations), while the majority of detections are of bodies with sizes calculated to be in the tens of metres range. However, these detections have all been essentially made by luck, when a professional or amateur telescope happened to be pointing in the right direction, rather than as a result of organised monitoring, which would provide statistically useful data on the frequency of such events.

In a paper published on the arXiv database at Cornell University and submitted to the Astrophysical Journal Letters, Ko Arimatsu of the Astronomical Observatory at Kyoto University, Kohji Tsumuru of the Department of Natural Science at Tokyo City University, Fumihiko Usui of the Department of Space Astronomy and Astrophysics at the Japan Aerospace Exploration Agency, and Jun-Ichi Watanabe of the Astronomy Data Center at the National Astronomical Observatory of Japan, report the first detection of an impact event on Jupiter by the Planetary ObservatioN Camera for Optical Transient Surveys observation system, which was set up to continuously monitor the surface of Jupiter for impact flashes, and commenced operating on 9 September 2021.

The event was detected at 1.24 pm GMT on 15 October 2021 (i.e. 36 days after the system began continuous observations of Jupiter), in both the visual and methane-absorbance bands of the spectrum, in the north tropical zone of Jupiter. The flash was also seen by two amateur astronomers in Japan, and one in Singapore; these observations provide a corroboration of the event which confirms it occurred on Jupiter, not in the Earth's atmosphere. No subsequent after-effects of the impact could be observed from Earth. An observation by the Juno Spacecraft made 28 hours after the impact showed some darkening at the site of the event, although it is impossible to determine if this was related.

Impact flash on Jupiter on 15 October 2021. Arimatsu et al. (2022).

The impact had a maximum apparent magnitude of 4.7 in the visual part of the spectrum (comparable to the Jovian moon Io at it's brightest), and lasted for about 5.5 seconds. This is brighter and longer lasting than any Jovian impact recorded since the Shoemaker Levy 9 impact observed by the Hubble Space Telescope in 1994.

The impact was significantly brighter at visible wavelengths than it was in the methane-absorbance part of the spectrum, which Arimatsu et al. attribute to reflection of light at these wavelengths by the Jovian clouds. Arimatsu et al. further calculate that the impact released an energy of about 740 000 000 megajoules, roughly equivalent to the detonation of 1.8 megatons of TNT. This is roughly equivalent to the amount of energy thought to have been released by the Tunguska explosion in 1908, and an order of magnitude greater than any Jovian impact previously recorded, with the exception of the Shoemaker Levy 9 impact.

Based upon this, Arimatsu et al. calculate that the impactor would have had a mass of about 4 100 000 kg, which would equate to a diameter of roughly 15-30 m, depending on the density and composition of the object.

By calculating the amount of time known to have been dedicated to the direct observation of Jupiter by telescopes capable of detecting large impacts since 2010, and the number of impacts observed in this time, Arimatsu et al. calculate that such impacts are 2-3 orders of magnitude more common on Jupiter than on Earth. This is an order of magnitude greater than previous estimates based upon observations of impact craters on the Jovian moons. 

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