Outbreak of Cholera in the eastern Democratic Republic of Congo.

On 14 December 2022, a Cholera epidemic was officially declared by the Governor of the North Kivu Province, in the Democratic Republic of Congo, following the isolation of Vibrio cholerae among 140 of 247 samples collected from suspected cases in the Nyiragongo Health Zone, according to a press release issued by the World Health Organization on 10 February 2023. As of 4 February 2023, a total of 4386 cholera cases (of which 1009 are laboratory-confirmed) with 16 deaths (a mortality rate of 0.4%) have been reported. Cholera is endemic in the eastern part of the Democratic Republic of the Congo, including Ituri, North Kivu, South Kivu, and Tanganyika provinces, with cases reported through the year. 

A multisectoral community-based response has been implemented, including a Cholera vaccination campaign. However, considering the fragile context in which this outbreak is taking place, ongoing armed conflicts with further displacements, concurrent epidemics, inadequate levels of access to health care, poor drinking water, hygienic and sanitary conditions, and population movements between the affected health zones and neighbouring countries (including Rwanda and Uganda), the World Health Organization assesses the risk posed by this outbreak as high at the national and regional level, and low at the global level.

Cholera is endemic in several provinces in the Democratic Republic of the Congo. However, from mid-November to the end of 2022, there has been an upsurge in the number of reported cholera cases in the health zones of Nyiragongo and Karisimbi, in the province of North Kivu. Since then, cases have shown a declining trend.

Number of Cholera cases (suspected and confirmed) reported in Nyiragongo and Karisimbi health zones. World Health Organization.

In Nyiragongo, the number of new Cholera cases (suspected and confirmed) increased from 51 in week 47 (21-27 November) to 556 cases in week 50 (12-18 December) of the year 2022, and to 683 cases in week 52 (26 December 2022- 1 January 2023). On 14 December 2022, a Cholera epidemic was officially declared by the Governor of North Kivu Province, following isolation of Vibrio cholerae in the stool of 140 cases from Nyiragongo Health Zone at the local laboratory in Goma.

As of 4 February 2023, a total of 4386 cholera cases (1009 laboratory-confirmed) with 16 deaths have been reported, of which 4011 (91.5%) are from Nyiragongo and 375 (8.5%) from Karisimbi. In the Nyiragongo Health Zone, the most affected age group is 5-14 years (30.1%), followed by 1-4 years (29.7%) and 15-29 years (16.6%); children under the age of one represent 8% of cases.

In total, 15 health areas including seven in the Nyiragongo Health Zone (Kanyaruchinya, Kibati, Kiziba, Mudja, Munigi, Ngangi III and Turunga) and eight in Karisimbi Health Zone (Baraka, Bujovu, Kasika, Katoyi, Majengo, Methodiste Mugunga and Muugano Solidarite) are currently affected by the Cholera epidemic.

In the Nyiragongo Health Zone, the Kanyaruchinya Health Area is the most affected, contributing to 73.3% of all suspected Cholera cases reported from Nyiragongo. In Karisimbi Health Zone, the Methodist Health Area is the most affected with 59.4% of all cases, followed by Baraka and Lasika health areas (both contributing to 7.3% of cases from Karisimbi Health Zone).

Cumulative number of Cholera cases (suspected and confirmed) by health area in Niyragongo and Karisimbi health zones, as of 4 February 2023. Nord Kivu Provincial Health Division/World Health Organization.

The cholera outbreak is principally affecting internally displaced populations, with 97% of the cases reported among internally displaced people in the Nyiragongo Health Zone, and 59% of cases among internally displaced people reported from the Methodist Health Area of Karisimbi Health Zone, which houses the Don Bosco Internally Displaced Population Camp. However, the outbreak is also spreading across the surrounding communities with nearly 3% of the cases in the Nyiragongo Health Zone and 41% of the cases in the Karisimbi Health Zone belonging to the host community.

Cholera is an acute enteric infection caused by ingesting the Bacterium Vibrio cholerae a Gram-negative, comma-shaped Gammaproteobacterium, related to other pathogenic Bacteria such as Yersinia pestis (Bubonic Plague), and Esherchia coli (food poisoning), which present in contaminated water or food. It is mainly linked to insufficient access to safe drinking water and inadequate sanitation. Cholera is an extremely virulent disease that can cause severe acute watery diarrhoea resulting in high morbidity and mortality, and can spread rapidly, depending on the frequency of exposure, the exposed population and the setting. Cholera affects both children and adults and can be fatal if untreated.

SEM image of Vibrio cholerae Bacteria. Kim et al. (2000).

The incubation period is between 12 hours and five days after ingestion of contaminated food or water. Most people infected with Vibrio cholerae do not develop any symptoms, although the bacteria are present in their faeces for 1-10 days after infection and are shed back into the environment, potentially infecting other people. The majority of people who develop symptoms have mild or moderate symptoms, while a minority develop acute watery diarrhoea and vomiting with severe dehydration. Cholera is an easily treatable disease. Most people can be treated successfully through prompt administration of oral rehydration solution.

The consequences of a Humanitarian crisis, such as disruption of water and sanitation systems, or the displacement of populations towards inadequate and overcrowded camps, can increase the risk of Cholera transmission, should the Bacteria be present or introduced. A multisectoral approach including a combination of surveillance, water, sanitation and hygiene, social mobilization, treatment, and oral Cholera vaccines is essential to control Cholera outbreaks and to reduce deaths.

Multisectoral coordination has been established at the provincial level, and daily coordination meetings are held in Kaniyaruchinya (Nyiragongo Health Zone). The incident management system was activated at the World Health Organization office. A budgeted preparedness and response plan has been developed and several partners are involved in the response, including the World Health Organization, which supports the Provincial Health Division in the implementation of the health sector response in collaboration with the Ministry of Health and the other partners, such as the United Nations High Commissioner for Refugees, International Organization for Migration, Médecins Sans Frontières, UNICEF, World Food Programme, and Save the Children.

A surveillance and laboratory commission has been set up by the North Kivu Provincial Health Division with the support of the World Health Organization and other partners. Four data managers have been trained and equipped with computers by the World Health Organization. Training on case definition has been provided to healthcare workers and community health workers; investigation teams have also been trained on active case finding. Surveillance activities are ongoing, including active case finding, alert notification and investigation, and contact tracing and follow-up. Data is collected daily from Oral Rehydration Points, Cholera Treatment Units and Cholera Treatment Centers. Samples are regularly collected also from suspected cases registered outside the outbreak area in order to assess the extent of the epidemic. Data is analyzed on a daily basis and shared with partners for operational decision-making. The World Health Organization has also supported the National Biological Research Institute in Goma with sample transportation.

The World Health Organization and partners have supported the establishment of 56 Oral Rehydration Points in Internally Displaced Population sites, four Cholera Treatment Units (Kibati, Kanyarucinya, Kahembe, and Don Bosco) and two Cholera Treatment Centers (Munigi, Kiziba) in the most affected health areas, with a total capacity of 205 beds. The World Health Organization and partners also provided support for the free provision of basic health care in functional health structures in the two affected health zones to ensure the maintenance of essential health services for vulnerable populations.

An Infection Prevention and Control/Water, Hygiene and Sanitation commission has been set up by the North Kivu Provincial Health Division and supported by partners including the World Health Organization and UNICEF. Systematic decontamination of households and public spaces is implemented by trained teams. Training for safe and dignified burials is also carried out. In Internally Displaced Population sites a total of 1706 latrines, 293 showers, 91 hand-washing stations and 62 well sites have been established. Regular supply of water is made through cisterns. Training for healthcare workers and hygiene workers on Infection Prevention and Control practices is also carried out regularly.

Several advocacy meetings have been held with community leaders and political-administrative authorities. Community workers have been trained to raise awareness about cholera, and preventive measures are communicated door-to-door and during public meetings with the affected population.

At the national level, coordination meetings were organized to ensure the preparation of the vaccination campaign against Cholera in the two affected health zones. The World Health Organization provided support to the Ministry of Health for the mobilization from the vaccination International Coordination Group of 364 137 doses of oral cholera vaccines in the two affected health zones. With the support of the Global Alliance for Vaccines and Immunization, after its launch by the Governor of North Kivu Province on 25 January 2023, the Oral Cholera Vaccination campaign in three health zones of North Kivu Provincial Health Division (including in Internally Displaced Population sites) took place between 25-30 January 2023 and immunized 351 207 people aged one year and older out of a target of 364 137, giving a coverage of 96.4%.

Cholera is endemic in parts of Democratic Republic of Congo. In 2022, according to data from the National Integrated Disease Surveillance and Response System, a total of 18 403 suspected cases of cholera, including 302 deaths (a fatality rate of 1.6%), were notified in the Democratic Republic of Congo, in 104 health zones in 19 of the 26 provinces of the country.

However, the current epidemic is showing a rapid upsurge in a fragile context, with high risk environments such as Internally Displaced Population camps. For years, the Democratic Republic of Congo has been experiencing several armed and community conflicts, particularly in the east, putting the country in a state of unprecedented Humanitarian and health crisis.

Due to internal armed clashes, which intensified in 2022, nearly 450 857 new Internally Displaced Persons arrived in North Kivu (which already hosts 1.9 million Internally Displaced people). Of them, 53.4% (240 579) are hosted in the territory of Nyiragongo and particularly 97.7% (235 111) in Internally Displaced Population sites, which are characterized by overcrowding, poor hygiene and sanitation conditions, very limited access to drinking water, latrines and basic health services. In addition, population movements are regularly observed between the affected health zones and the other health zones in the province of North Kivu as well as the rest of the country, where the populations also have limited access to drinking water, good hygiene and sanitation conditions, as well as to health care facilities. Moreover, the current rainy season may favor the spread of the epidemic in other health zones.

With the ongoing armed conflicts, displacements are likely to continue, leading to a worsening of the Humanitarian context and the vulnerabilities of the populations, including the need for basic social services. All this is evolving in a context of a fragile health system; recurrent attacks on hospital infrastructures and reduced availability of services. Other outbreaks are also ongoing (COVID-19, Yellow Fever, Poliomyelitis, Measles, Monkeypox, Meningitis, etc.) and there are extremely limited Human, material and financial resources.

The risk of Cholera spreading to neighboring countries cannot be ruled out. Indeed, there are population movements between the affected health zones and neighboring countries, including Rwanda and Uganda.

The affected health zones border the city of Goma, which has an international airport. Countries in the Great Lakes sub-region (Rwanda, Uganda, Burundi), which are most at risk of Cholera importation from the current epidemic hotspots in North Kivu, have inadequate levels of access to health care, poor drinking water, hygienic and sanitary conditions. A Cholera epidemic is also ongoing in Burundi with 120 suspected cases and 1 death reported as of 7 February 2023. This epidemic affects the city of Bujumbura, which is located on the shores of Lake Tanganyika on the border with South Kivu, with population movements across the border.

The outbreak is occurring against a backdrop of a surge in Cholera outbreaks globally, which has constrained the availability of vaccines, tests, and treatments. Considering the above-described scenario, the World Health Organization assesses the risk posed by this outbreak as high at the national and regional level, and low at the global level.

The World Health Organization advises that a multi-pronged approach is essential to combat Cholera and reduce mortality. The measures used combine surveillance, improvement of water supply, sanitation and hygiene, social mobilization, treatment of the disease and oral Cholera vaccines. Countries affected by Cholera are advised to strengthen disease surveillance and national preparedness to rapidly detect and respond to possible outbreaks.

The World Health Organization recommends improving access to proper and timely case management of Cholera cases, improving access to safe drinking water and sanitation infrastructure, as well as improving infection prevention and control in healthcare facilities. These measures along with the promotion of preventive hygiene practices and food safety in affected communities are the most effective means of controlling Cholera. Effective risk communication and community engagement strategies are needed to encourage behavioral change and the adoption of appropriate preventive measures.

Measures aimed at improving environmental conditions include applying long-term sustainable solutions for water supply, sanitation and hygiene in Cholera-prone areas. In addition to Cholera, these interventions can also prevent a wide range of other water-borne diseases and contribute to achieving goals in education and the fight against poverty and malnutrition. Solutions for water supply, sanitation and hygiene related to cholera are in line with the Sustainable Development Goals.

Rapid access to treatment is essential during a Cholera outbreak. Oral rehydration should be available in communities and not just in larger health centers that can offer intravenous infusions and management at any time. With rapid and appropriate care, the case fatality rate should remain below 1%.

Community mobilization must continue as an integral part of the response and should cover information on the symptoms of Cholera, on the precautions to take to protect against the disease, and the need to promptly seek care when symptoms appear.

The oral Cholera vaccines should be used in conjunction with improvements in water and sanitation to control Cholera outbreaks and for prevention in targeted areas known to be at high risk for Cholera.

The World Health Organization recommends Member States to strengthen and maintain surveillance for Cholera, especially at the community level, for the early detection of suspected cases and to provide adequate treatment and prevent its spread. Early and adequate treatment limits the mortality rate of patients to less than 1%.

The World Health Organization does not recommend any travel or trade restrictions to the Democratic Republic of Congo based on the currently available information.

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Nine confirmed deaths after Cyclone Gabrielle sweeps along the east coast of New Zealand's North Island.

Nine people have now been confirmed dead after Cyclone Gabrielle swept across the east coast of North Island, New Zealand, on Sunday 112 February 2023. About five thousand more people are missing following the event, and while it is thought that most have simply been cut off in remote areas by the damage that the storm has done to the country's communications network, ten missing people are considered to be at high risk. A week after the event about 62 000 households are still without electricity, 40 000 of them in the Hawkes Bay area, with about 2000 people still staying in evacuation centres.

Flooding in the town of Wairoa on the east coast of North Island, New Zealand, following the passage of Cyclone Gabrielle. Hawkes Bay Civil Defense. 

The storm brought the second highest rainfall ever recorded in a single day in New Zealand, 348 mm in 24 hours at Whangārei in the Northland Region. as well as sealevels 30-40 cm above normal, winds gusting at up to 155 km per hour, and waves as high as 11 m. The storm brought widespread flooding, with numerous landslides sweeping away roads and buildings. Landslides are a common problem after severe weather events, 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. The flooding was made worse due to a rainstorm which hit North Island at the end of January, which has already left the ground waterlogged and drainage systems at capacity across much of the affected area, with between 10 and 20% of the floodwaters unleashed by Gabrielle thought to have been linked to this earlier event.

Water pouring from a storm drain into a street at Te Awanga to the southeast of Auckland on Tuesday 14 February 2023. Warren Buckland/AP.

Tropical storms, called Cyclones in the Indian Ocean and South Pacific, are caused by solar energy heating the air above the oceans, which causes the air to rise leading to an inrush of air. If this happens over a large enough area the inrushing air will start to circulate, as the rotation of the Earth causes the winds closer to the equator to move eastwards compared to those further away (the Coriolis Effect). This leads to tropical storms rotating clockwise in the southern hemisphere and anticlockwise in the northern hemisphere. These storms tend to grow in strength as they move across the ocean and lose it as they pass over land (this is not completely true: many tropical storms peter out without reaching land due to wider atmospheric patterns), since the land tends to absorb solar energy while the sea reflects it..

The formation of a tropical cyclone. Natural Disaster Management.

Cyclone Gabrielle initially formed over the Coral Sea, to the east of Queensland, where the Australian Bureau of Meteorology recorded sea surface temperatures of 30°C earlier this month, around 5°C hotter than the threshold generally assumed for the formation of tropical storms. This came amid high sea temperatures across the Western Pacific Warm Pool region driven by three consecutive years of La Niña conditions in the region, which has led to a huge build up of thermal energy in the southern Pacific, with temperatures 4°C above normal recorded 150 m below the surface.

Position of the Warm Pool in the western Pacific under La Niña conditions. Bell et al. (2011).

The La Niña weather system is the opposite of the El Niño weather system, in which unusually cold surface temperatures spread across the equatorial Pacific from the upwelling zone on the South American coast. This traps warm water from the western Pacific, preventing it from spreading east and warming the central Pacific. This leads to lower evaporation over the (cooler) east Pacific, leading to low rainfall on the west coast of South America, and higher evaporation over the (warmer) west Pacific, leading to higher rainfall over East and Southeast Asia and northern Australia.

The effects of a La Niña weather system in December-February. NOAA.

Despite the obvious danger of winds of this speed, which can physically blow people, and other large objects, away as well as damaging buildings and uprooting trees, the real danger from these storms comes from the flooding they bring. Each drop millibar drop in air-pressure leads to an approximate 1 cm rise in sea level, with big tropical storms capable of causing a storm surge of several meters. This is always accompanied by heavy rainfall, since warm air over the ocean leads to evaporation of sea water, which is then carried with the storm. These combined often lead to catastrophic flooding in areas hit by tropical storms. 

The formation and impact of a storm surge. eSchoolToday.

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Two miners killed in collapse at Queensland zinc mine.

Two mineworkers have been confirmed dead following a collapse at a zinc mine in Queensland at 8.55 am local time on Wednesday 15 February 2023. Dylan Langridge, 33, and Trevor Davis, 36, were working at the Dugald River Mine near Cloncurry when the incident happened. The men were reportedly driving in a light vehicle 125 m below ground when a void opened up beneath them, into which their vehicle, and a drill rig following them, fell. The driver of the drill rig was able to escape with minor injuries, but Langridge and Davis were buried by rocks and debris, and their bodies not recovered until the following day, 25 m below the level where they disappeared.

Dylan Langridge (left) and Trevor Davis (right), killed in a fall at a zinc mine in Queensland on 15 February 2022. ABC.

The fatalities are understood to have been caused by the collapse of part of an access tunnel into a stope (large underground cavern created by ore-extraction),. Operations at the mine have now ceased pending an investigation into the incident. Mining safety remains a cause of concern in Queensland, and elsewhere in Australia, due to the number of fatalities occurring within mines. The nation's mining companies have repeatedly insisted that safety at mines is a high priority, while groups representing miners claim it is often difficult for workers to raise concerns about safety issues, and that individuals who do so often run the risk of reprisals.

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Magnitude 6.0 Earthquake off the coast of Matabao Island in Masbate Province, Philippines.

The Philippine Institute of Volcanology and Seismology recorded a Magnitude 6.0 Earthquake at a depth of 10 km about 11 km to the east of the island of Matabao in Masbate Province, slightly before 2.10 am local time on  Thursday 16 February 2023 (slightly before 6.10 pm on Wednesday 15 February GMT). People have reported feeling this event across the central Philippines, but there have been no reports of any damage or injuries associated with this Earthquake, and no tsunami warning was issued.

The location of the 16 February 2023 Masbate Province Earthquake. USGS.

The geology of the Philippines is complex, with the majority of the islands located on the east of the Sunda Plate. To the east of this lies the Philippine Sea plate, which is being subducted beneath the Sunda Plate (a breakaway part of the Eurasian Plate); further east, in the Mariana Islands, the Pacific Plate is being subducted beneath the Philippine Sea Plate. This is not a smooth process, and the rocks of the tectonic plates frequently stick together before eventually being broken apart by the rising pressure, leading to Earthquakes in the process. Material from the subducting Philippine Plate is heated by the temperature of the Earth's interior, causing lighter minerals to melt and the resultant magma to rise through the overlying Sunda Plate, fueling the volcanoes of the Philippines

Subduction beneath the Philippines. Yves Descatoire/Singapore Earth Observatory.

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Asteroid 2023 CX1 falls to Earth over the English Channel.

Slightly before 9.20 pm local time (8.20 pm GMT) on Sunday 12 February 2023, Hungarian astronomer Krisztián Sárneczky of the Konkoly Observatory observed a Near Earth Object moving rapidly across the northern sky. He recorded this as SAR2667, and reported the finding to the International Astronomical Union's Minor Planet Centre, where the sighting was confirmed, and given the provisional designation 2023 CX1, which implies that it was the 48th asteroid (object X1 - in numbering asteroids the letters A-Z, excluding I, are assigned numbers from 1 to 25, with a number added to the end each time the alphabet is ended so that A = 1, A1 = 26, A2 = 51, etc., which means that X1 = 25 + 23 = 48) discovered in the first half of February 2023 (period 2023 C - the year being split into 24 half-months represented by the letters A-Y, with I being excluded). Later that evening the European Space Agency announced that it's scientists had calculated the asteroid was likely to impact the Earth the following day, somewhere around the French city of Rouen. 

Image of 2023 CX1 captured by the Osservatorio Astronomico Sormano in Italy slightly before midnight local time (slightly before 11.00 pm GMT) on Sunday 12 February 2023. This was one of the observations which enabled the European Space Agency to track the path of the asteroid, which was only the seventh asteroid detected before impacting the Earth, and predict the area in which it was likely to fall. Osservatorio Astronomico Sormano.

Slightly before 3.00 am GMT on Monday 13 February, witnesses across southern England and Wales, northern France, most of Belgium, the southern part of the Netherlands and western Germany reported seeing a bright fireball over the English Channel, disappearing somewhere to the north of Dieppe. 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, although on this occasion the object was confirmed to be the newly discovered asteroid, 2023 CX1.

A fireball meteor caused by asteroid 2023 CX1 entering the Earth's atmosphere over the English Channel, observed from the southern Netherlands. Gijs de Reijke.

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).

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.

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.

The calculated trajectory of 2023 CX1 as it fell to Earth. Simon Anghel/Institut de mécanique céleste et de calcul des éphémérides/Observatoire de Paris. 

Asteroid 2023 CX1 is calculated to have been about 233 000 km from the Earth (i.e. about 61% of the distance to the Moon) when it was discovered, and to previously have had a 799 day (2.19 year) orbital period, with an elliptical orbit tilted at an angle of 3.56° to the plain of the Solar System which took in to 0.92 AU from the Sun (92% of the distance at which the Earth orbits the Sun) and out to 2.45 AU (245% of the distance at which the Earth orbits the Sun, and more than the distance at which the planet Mars orbits the Sun). It would therefore have been classed as an Apollo Group Asteroid (an asteroid that is on average further from the Sun than the Earth, but which does get closer). This means that Asteroid 2023 CX1 had occasional close encounters with the Earth, with the last having happened in June 2000.

The former orbit of asteroid 2023 CX1. JPL Small Body Database.

Asteroid 2023 CX1 is thought to have had a diameter of about a metre, and to have exploded in an airburst in diameter), and an object of this size would be expected to explode in an airburst (an explosion caused by superheating from friction with the Earth's atmosphere, which is greater than that caused by simply falling, due to the orbital momentum of the asteroid) more than 40 km above the English Channel. Nevertheless, it was calculated that the asteroid could potentially have scattered fragments on the coast of Normandy between Dieppe and Doudeville, with the potential to have produced pieces as large as 2 kg. A search was organised by the Fireball Recovery and Interplanetary Observation Network involving many volunteers and researchers, who assembled on Wednesday 15 February to scour this area. This led to the discovery of a single fragment in a field close to the town of Saint-Pierre-le-Viger, by student Loïs Leblanc. 

The single known surviving fragment of asteroid 2023 CX1, a piece of black rock weighing about 100g, found in a field near the town of Saint-Pierre-le-Viger, by student Loïs Leblanc on 15 February 2023. Fireball Recovery and Interplanetary Observation Network.

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Neoponera vejestoria: A Ponerine Ant from Miocene Dominican Amber, and its implications for the evolution of the ecological niches occupied by Ants in the Greater Antilles.

The makeup of modern ecological communities is determined by three factors, speciation, migration, and extinction. The first two of these can be largely understood through the examination of extant species, but our knowledge of past extinction events is entirely derived from the fossil record. Extinction events can create opportunities for surviving species to adapt into vacant niches, but can also lead to the vanishing of those niches, and of co-dependent niches and the organisms that occupy them. Island ecosystems are particularly vulnerable to extinction events, and their ecological communities are therefore particularly prone to being modified in this way. This makes the fossil history of island ecosystems, which are likely to have been shaped by numerous extinction events. of particular interest to evolutionary ecologists, although very few islands have fossil deposits that record past faunas in sufficient detail to be useful.

The island of Hispaniola in the Greater Antilles is home to 126 indigenous Ant species, drawn from a wide range of Neotropical groups which occupy different ecological roles. The island is also home to an excellent Fossil Lagerstätte, the Dominican Amber deposits, from which over 1100 species of Early Miocene Insects, including 86 species of Ants. The fauna recorded in this amber deposit is very similar to that of the modern Neotropics, with 84 of the described Ant species being placed in extant Neotropical genera. However, about a third of the genera found in the fossil fauna, while still present in the wider Neotropics, are absent from not just Hispaniola, but the wider Greater Antilles island group, implying that they have suffered local extinctions over the 16 million years since the amber was deposited. The ancient and modern faunas were studied by biologist Edward O. Wilson in the 1980s, who concluded that larger species and those with more specialize ecologies were more likely to have gone extinct. Since Wilson carried out his study, considerably more has been learned about both the fossil and living Hispaniolan Ant faunas, but Wilson's observations remain unchallenged.

In a paper published in the journal BMC Biology on 8 February 2023, Gianpiero Fiorentino of the Federated Department of Biological Sciences at the New Jersey Instituteof Technology, John Lattke of the Departamento de Zoologia at the Universidade Federal Do Paraná,  Adrian Troya of the Departamento de Biología at the Escuela Politécnica Nacional, Christine Sosiak, also of the Federated Department of Biological Sciences at the New Jersey Institute of Technology, Minsoo Dong of the Applied Biology Program at Kangwon National University, and Phillip Barden, again of the Federated Department of Biological Sciences at the New Jersey Institute of Technology, and of the Division of Invertebrate Zoology at the American Museum of Natural History, describe a new species of Ponerine Ant from Miocene Dominican Amber, and discuss its implications for the evolution of the ecological niches occupied by Ants in the Greater Antilles.

The new species is assigned to the Subfamily Ponerinae, one of the largest and most diverse Ant families, both in ecological and morphological terms, and to the genus Neoponera, which is one of the more diverse genera of Neotropical Ponerine Ants, with 58 extant species, divided among seven species groups. The majority of Neoponera species are arboreal in habit, which is unusual in Ponerine Ants, although the genus is quite ecologically variable, with individual species having lifestyle strategies which vary from generalist ground-dwelling hunters, to specialist Termite raiders, to mutuaslistic relationships with certain Trees, which they protect from herbivores in return for food and nesting spaces. Despite this ecological adaptability, the genus Neoponera does not appear to do well in island ecosystems, with a few species in the Lesser Antilles but none in the Greater Antilles or on other Neotropical islands.

The new species is named Neoponera vejestoria, where 'vejestoria' derives from the Spanish 'vejestorio' meaning an old person or thing. The new species is placed in the genus Neoponera on the basis of its eyers, which are convex eyes placed at about head mid-length (found in all members of the genus), its well developed aroliae (a lobe on the leg to which the pretarsus attaches, again well developed in all members of the genus), and its slit-shaped propodeal spiracle (breathing opening, found in most members of the genus). It resembles members of the foetida and aenescens species groups, being assigned to the former group on the basis of its well developed malar carinae (ridges on its 'cheeks') and the positioning of its eyes.

Photomicrographs of Neoponera vejestoria (Holotype, MNHNSD FOS 18.01). (A) Head in frontal view. (B) Body in dorsal view. (C) Body in lateral view. Scale bars: (A) 1 mm; (B), (C) 2 mm. Fiorentino et al. (2023).

Based upon its morphology, Neoponera vejestoria is thought to have been a ground-dwelling generalist predator. It is the first known fossil species within the genus Neoponera, as well as the first known fossil member of the Pachycondyla genus group of Ponerine Ants from the Neotropics. It is also the largest predatory Ant known from the island of Hispaniola, either in the Miocene Amber deposits or today, although it would only be considered a medium-sized compared to a wider sampling of Ants; most modern Ants on Hispaniola are quite small, and while the size-range present in the Miocene Ants is larger, none of them are exceptionally large.

Neoponera vejestoria (Holotype BALDR0443): (A) Lateral view of mesosoma; (B) Dorsal view of posterior mesosoma and propodeum; (C) Lateral view of gaster; (D) Ventral view of mesosoma; (E) Metatarsi 1-5; (F) Arolium and metatarsal claws; (G) Metapleural gland. Scale bars: (A) 2 mm, (B) 1 mm, (C) 2 mm, (D) 2 mm, (E) 0.25 mm, (F) 0.125 mm, (G) 0.25 mm. Fiorentino et al. (2023).

Living Ponerine Ants are less morphologically variable and, on average, smaller than fossil species. This is less true if only Ants from Hispaniola are considered, where the largest Ponerine Ants other than Neoponera vejestoria, livening or fossil, all belong to the genus Odontomachus, which is the only Ant genus on the island today containing medium-sized species. However, it is likely that the Dominican Amber deposits do not represent the full range of Miocene Ants on the island, and that other larger Ants may have existed on the island at that time.

Computerized tomographic reconstruction of Neoponera vejestoria to illustrate difficult to view characters. (A) Head in front view; (B) Profile view of mesosoma and gaster; Dorsal view of head, posterior mesosoma, and propodeum as a computerized tomographic reconstruction (C) and as a photograph of the fossil (D). Fiorentino et al. (2023).

Fiorentino et al.'s study suggests that the fauna of Hispaniola has been shaped not just by the extinction of lineages of Ants, but also the loss of the ecological niches which they once occupied. Predatory Ants on the island have always tended to be on the small side, but the range of sizes was clearly greater in the Early Miocene than it is today. Furthermore, Ants with more specialized feeding strategies, such as the Blind Army Ants of the genus Neivamyrmex, the Trap-jaw Ants, Acanthognathus spp., and the subterranean predatory Ants, Acanthostichus spp., have also died out on the island. The discovery that the island was once occupied by the Ponerine Ant Neoponera vejestoria provides further evidence of the modification of the island's ecological community through the extinction of certain ecological traits. Neoponera vejestoria is at least a third larger than any living predatory Ant on the island, which is a conspicuous difference in size, and likely to have been a ground-nesting generalist predator, which is not in itself unusual.

Artistic reconstruction of Neoponera vejestoria. Minsoo Dong in Fiorentino et al. (2023).

The Ant fauna of the Miocene of the island of Hispaniola is likely to be severely under-represented in Dominican Amber. The amber was formed from a resin extruded by a Leguminous Tree, and therefore best preserves the Insects which lived on, or at least visited the canopy of these trees, as well as, to a lesser extent, species which lived on the ground beneath. Insects which lived elsewhere on the island are highly unlikely to have been preserved at all. This could well imply that the Miocene size-range of Ants on the island was wider than has been preserved in the fossil record. Other lineages of larger Ants besides Neoponera appear to have been lost on Hispaniola, such as the large-bodied genus Paraponera, which is found in Dominican amber, but absent from the Caribbean region today.

Mammals, and other Vertebrates, often face selective pressures against larger sizes when groups become isolated on islands, but this is much harder to demonstrate in Insects, although it has previously been demonstrated in Carabid Beetles on European islands.

Excluding Neoponera vejestoria, the largest Ant species found on Hispaniola in both the Miocene and modern faunas belong to the genus Odontomachus. These Ants are ground dwelling generalist predators, something they share with Ants of the genus Neoponera. Today, these two Ant genera are seldom encountered on the same island, with Odontomachus being found on Hispaniola and the other islands of the Greater Antilles, as well as Cocos, Barbados, and Tobago, while Neoponera is only found on the island of Margarita. Fiorentino et al. therefore consider it possible that the two types of Ant compete for similar niches, which may have been a driver of the extinction of Neoponera on Hispaniola.

The discovery of Neoponera in Dominican Amber highlights the fact that these deposits still have much to tell us about the Miocene fauna of Hispaniola, and the way in which the island's ecology has changed over time, despite over five decades of study on the subject.

Neoponera vejestoria is clearly a distinct species, but nevertheless is morphologically very similar to extant species in the same genus, something which has been observed in other Ants from Miocene Dominican Amber. Most modern members of the genus Neoponera inhabit specialist niches, and the group is predominantly arboreal today, but some members are still ground-dwelling generalist predators, and it has previously been suggested that this is likely to be the ancestral state for the genus, a hypothesis supported by the discovery of Neoponera vejestoria, although the alternative hypothesis, that Neoponera vejestoria had secondarily adopted a ground-dwelling generalist lifestyle as an adaptation to island life, cannot be excluded.

The discovery of Neoponera vejestoria also sheds light on the history of the wider  Pachycondyla genus group (which includes Pachycondyla, Neoponera, and Dinoponera, among others), which are important members of Neotropical ecosystems, being the first fossil Ant confidently placed within the group, and the first fossil member of an extant genus in the group. Other fossils have previously been referred to this group, but none of them with confidence, and  Fiorentino et al. suggest that all of these specimens need re-examination, to shed better light on the history of the group. Molecular clock estimates of the age of the genus Neoponera have suggested that it first appeared between 26 and 12 million years ago, while the foetida species group has been thought to be no more than 12 million years old. A better understanding of the fossil record of the Pachycondyla genus group would clearly lead to better calibration of these molecular estimates.

The discovery of Neoponera vejestoria provides a rare example of island extinction in the fossil record. This is almost certainly linked to the body size of the species, which is likely to have placed it at greater risk of extinction in an island ecosystem. As the ecological niche occupied by Neoponera vejestoria is still in existence, this demonstrates that a large size in itself is a threat to Ant species on islands.

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