Using Environmental DNA to search for Crocodiles in Madagascar.

The world is currently suffering from multiple interconnected environmental crises, including a rapid loss of biodiversity in many parts of the world. Madagascar, a global biodiversity hotspot with a large number of species found nowhere else, is considered to be particularly at risk, due to unprecedented rates of habitat loss. However, tracking this loss is challenging, as monitoring species loss involves a large amount of labour intensive work by specialist taxonomic experts, often involving access to expensive equipment.

Environmental DNA offers a potential way to reduce this workload, allowing for monitoring to be carried out by non-specialist staff collecting samples of sediment, water or even air. Since such methods to not require direct observation of threatened species, they are far less environmentally intrusive.

Nile Crocodiles, Crocodylus niloticus, were persecuted across their range by hunters seeking their skins, as well as harvesting of their eggs, until the mid-twentieth century. Since this time, the population has recovered in many parts of Africa due to conservation efforts. In Madagascar, the species is monitored by the Malagasy Crocodile Management Unit, which aims not just to establish the recovery of the species, but to minimise Human-Crocodile conflicts by helping people and livestock to avoid potentially lethal Crocodile encounters.

Previous work using environmental DNA has succeeded in detecting Crocodiles kept under laboratory conditions, but struggled to locate them in the wild, although methods such as water sweeps have proven more successful.

In a paper published in the journal Biodiversity and Conservation on 23 October 2025, Mai Fahmy of the Department of Undergraduate Biololgy at Stony Brook University, and the Division of Invertebrate Zoology at the American Museum of Natural History, Soja Manjakamanana Zafimanaoela of the Université d’Antananarivo, Njakamamapiadana Mamenofahasoavana Rinah and Jerison William Ranaivosolo of Stony Brook University's Centre ValBio in Madagascar, Noel Rowe of Primate Conservation Inc., Patricia Wright, also of the Centre ValBio, and of the Department of Anthropology and Interdepartmental Doctoral Program in Anthropological Sciences at Stony Brook University, and Evon Hekkala, also of the Department of Undergraduate Biololgy at Stony Brook University, and the Division of Vertebrate Zoology at the American Museum of Natural History, present the results of a study, in which they attempted to detect Crocodiles in Madagascar using sediment samples as well as specialist environmental DNA filters and Coffee filters, in an attempt to find a cost-effective method of detecting the Animals. 

Anivorano lake in northern Madagascar, traditionally held to be sacred. Here the local population periodically sacrifices Zebu Cattle to the Crocodiles, which are believed to contain the spirits of pas chiefs, in a ceremony that also involves dancing and singing. On such occasions, the Crocodiles are fed beef from a beach about 30 m long near a sacred tree, and subsequently typically remain in the area for about eight hours, basking on the beach or in the water.

Map of collection localities across Madagascar. TSP, Tsimanampetsotse National Park. Fahmy et al. (2025).

Fahmy et al. collected sediment from a belly print left on the beach by a Crocodile, Crocodile faecal matter, and water from an area close to where Crocodiles were basking. The water and faecal samples were subsequently passed through Coffee filters, which were retained. 

At the Ankarana Special Reserve, also in northern Madagascar, Fahmy et al. collected sediment samples from the river mouth leading into the Ankarana Cave System, with two samples collected from the footprints of Crocodiles, one adult and one juvenile. Water was also collected from a flooded cave entrance, and again filtered through a coffee filter.

Water samples were also collected from the Ihosy, Mananantanana, and Matitanana rivers in central and southeastern Madagascar, and filtered through specialist environmental DNA filters. These are wide, fast flowing rivers, used exclusively by the local population for transport, hygiene, and watering livestock. Samples were taken following sightings of Crocodiles, and only with the explicit permission of local communities.

Nile Crocodile, Crocodylus niloticus, spotted in the Matitanana River while sampling. Mai Fahmy in Fahmy et al. (2025).

Finally, four samples were collected from a submerged cave located in Tsimanampesotse National Park in southwest Madagascar. Nile Crocodiles have never been observed in these caves, although they are known to inhabit the nearby Onalahy River. The caves were, however, utilised by the extinct Madagascan Horned Crocodile, Voay robustus, which is thought to have died out about 1250 years ago. These samples were again filtered through Coffee filters. A sediment sample was also collected from beneath a subfossil Horned Crocodile in the caves.

A total of seventeen samples were collected and processed. Four of the samples were subsequently discarded because they were found to contain only Human DNA, and one because it contained Sheep DNA. In the remaining samples, the greatest number of species were recovered from the Coffee filter samples; although this did not represent the greatest diversity. Sediment and environmental DNA samples produced equal numbers of species, although greater overall diversity was recorded in the sediment samples. DNA associated with members of the Family Podicipedidae (Grebes) was recovered exclusively in the environmental DNA filters, while DNA associates with the Family Naididae (Tubifex Worms) was recovered exclusively from sediment samples.

Crocodile DNA was recovered from both sediment samples and Coffee filters, but not from specialist environmental DNA filters. However, Fahmy et al. do not suggest that this is because Coffee filters are superior to environmental DNA filters, as the later were only used to filter water samples from fast flowing rivers, where recovering Crocodile DNA is known to be difficult. 

Zebu Cattle drinking from Matitanana River. Mia Fahmy in Fahmy et al. (2025).

Three samples yielded Crocodile DNA, all from Lake Anivorano. These included the sediment sample taken from the Crocodile belly print, and the Coffee filters through which the faecal sample and water from close to Crocodiles basking in the lake were filtered. The analysis recovered these as belonging to the genus Crocodylus, and most likely as coming from Nile Crocodiles, Crocodylus niloticus, with a lower chance of coming from Orinoco Crocodiles, Crocodylus intermedius, of American Crocodiles, Crocodylus acutus, neither of which are found in Madagascar. 

The three most abundant species in the results were Cattle, Bos taurus, Chickens, Gallus gallus, and Domestic Pigs, Sus scrofa. Also detected were Ring-tailed Lemur, Lemur catta, and an unknown species of Grebe (Podicepepidae). This could not be identified to species level, although several Grebes are known from Madagascar, including the Little Grebe, Tachybaptus ruficollis, and the Madagascar Grebe, Tachybaptus pelzelnii. Interestingly, the Madagascar Grebe does not have any genetic material recorded in the GenBank database, against which the samples were compared.

The method developed by Fahmy et al. did not establish the presence of Crocodiles in anywhere they were not known to occur, but did establish that it was possible to detect Crocodiles using environmental DNA in Madagascar, and that it was possible to use Coffee filters as a means of recovering environmental DNA, a much cheaper option than specialist filters.

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The Earth approaches perihelion.

On Saturday 3 January 2025, at 5.15 pm, GMT, the Earth will reach its perihelion; the closest point on its orbit to the Sun, when it will be 147 099 894 km from the Sun. This is because the Earth's orbit is not a perfect circle, but varies by 3.3% over the course of a year. This perihelion distance varies each year; in 2025 the Earth reached 147 103 686 km from the Sun on 4 January and in 2027 it will reach 147 104 592 km from the Sun on 3 January.

The Earth's Aphelion and Perihelion. My Dark Sky.

This means that the Earth is at its closest to the Sun in the middle of the Northern Hemisphere's winter, counter-intuitive to most of the planet's population. This is, however, purely coincidental; the Earth's seasons are not caused by its distance from the Sun, which only varies by 3.3%, but rather by the tilt of the planet. The Earth is currently tilted at an angle of 25.5° to its plane of orbit (this varies on a timescale of tens of thousands of years, but remains fixed from the point of view of any human observer), causing the Sun to appear to rise higher and lower in the skies of each hemisphere as the year goes by. 

In the northern winter the Southern Hemisphere is tilted towards the Sun, so that the days are longer there (and in around the Southern Solstice in December, permanently above the horizon at the South Pole). In addition, the Sun being directly overhead means that the energy from the Sun has to pass through less of the atmosphere before it reaches the surface of the Earth, so that less energy is lost to the atmosphere, causing greater surface warming in the hemisphere pointed towards the Sun.

How the tilt of the Earth relative to its plane of orbit causes the seasons. ESA.

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A new reconstruction of the Yunxian 2 skull, and its implications for the relationship between the 'Archaic Homo sapiens' of China and Modern Humans.

The Middle Pleistocene, or Chibanian (roughly 774 100 to 129 000 years ago), has produced a range of Hominin fossils, with a surprising range of morphological diversity. Recent finds from Callao Cave on Luzon Island in 2007 and Rising Star Chamber in South Africa in 2013, have led to the description of two new Human species, Homo luzonensis and Homo naledi respectively, from this age. 

China has produced a diverse assemblage of Chibanian and older Hominin fossils, often labelled as 'Archaic Homo sapiens', although their relationship to Modern Humans has been the subject of debate for a long time. The Yunxian 1 & 2 crania were discovered on on a terrace of the Hanjiang River in the Yunyang District (formerly Yunxian) of Shiyan City, in Hubei Province, China, in 1989 and 1990. These skulls have been dated to between 1.1 million and 940 000 years ago, and are considered important for the understanding of the genus Homo in China, and to a certain extent the world, although both are heavily distorted, hampering attempts to reconstruct their original morphology and therefore phylogenetic relationships. 

The Yunxian 2 skull. Although the least distorted of the two crania from Yunxian, it is still partially crushed, and therefore difficult to interpret. Garry Todd/Hubei Provincial Museum/Wikimedia Commons.

In a paper published in the journal Science on 25 September 2025, a team of scientists led by Xiaobo Feng of the School of History and Culture at Shanxi University, Hubei Polytechnic University, and the Institute of Yunxian Man Site and School of History, Culture and Tourism, at Hanjiang Normal University, Qiyu Yin of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, and the College of Earth and Planetary Sciences of the University of the Chinese Academy of Sciences, Feng Gao of the Yunnan Institute of Cultural Relics and Archaeology, and Dan Lu, also of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, and the College of Earth and Planetary Sciences of the University of the Chinese Academy of Sciences, present a new reconstruction of the Yunxian 2 skull, and discuss the implications of that reconstruction for the relationship between the 'Archaic Homo sapiens' of China and Modern Humans.

Our understanding of the relationship between Modern Humans and our extinct Hominin relatives is based almost entirely on the reconstruction of the anatomy of extinct species from fossil specimens, many of which are quite distorted. Of the three fossil crania discovered at Yunxian, one (Yunxian 3) is still under preparation, having been found in 2022. Both of the previously discovered specimens are distorted, with Yunxian 1 being quite badly crushed as well. Computed tomography scans of Yunxian 2 have suggested that most of the deformation is due to the fragmentation and displacement of parts of the skull, rather than actual warping of the material. Feng et al. built a digital reconstruction of this fossil, using software to move parts back into their original position, and filling in some gaps with data from Yunxian 1. 

The reconstructed cranium is large and long, with a braincase which appears flattened in lateral view. It is smaller than the Harbin Xuchang crania, approximately the same size as the as Kabwe, Petralona, Bodo, Jinniushan, and Sangiran 17 crania, and larger than the Jebel Irhoud 1, Dali, and Maba crania. The reconstruction still lacks small parts of the zygomatic arches and the central incisors, but is otherwise intact. It contains a number of traits associated with earlier members of the genus Homo, including a thick supraorbital torus, a broad basicranium and palate, a long and low vault in lateral view, a receding frontal con￾tour, and a rather flat parietal contour, and a high, anteriorly projecting face. However, it lacks other traits associated with early members of the genus, such as a strongly angulated occipital with a prominent transverse torus. The specimen lacks the occipital bun, forward projecting midface, and general rounded 'en bombe' shape of Neanderthal skulls, and the upper parietal expansion of Modern Humans. The zygomaxillary region is transversely flat and faces anteriorly, similar to the Harbin, Dali, Jinniushan, and Hualongdong crania from Asia, as well as specimens assigned to Homo antecessor from Europe, as wellas Modern Humans. Its cheek￾bones are large and high.

Reconstruction of the Yunxian 2 cranium in standard views. (A) to (F) Anterior, posterior, inferior, superior, left, and right views, respectively. Brown colour indicates the fossil bone. The zygomatic bone and the tip of the left maxilla, as indicated with dark brown, were grafted and reconstructed by incorporating elements of Yunxian 1. White colour indicates the reconstructed parts inferred from the fracture edge and Yunxian 1. Neutral grey indicates the bones crushed and covered by other bones and matrix. Scale bar is 5 cm. Feng et al. (2025).

The matrix filling the skull is dense, and does not produce a good contrast with the bone material in computed tomography scans, preventing analysis of the features of the interior of the skull. However, Feng et al. were able to calculate an endocranial capacity of 1143 cm². However, the frontal lobe appears low and narrow, little expanded from the situation in early Homo, and unlike the expanded frontal lobes of Neanderthals and Modern Humans. 

Reconstruction of the endocranial cast of Yunxian 2. (A to F) Anterior, posterior, inferior, superior, left, and right views, respectively. Scale bar is 5 cm. Feng et al. (2025).

The traits which can be measured suggest that morphologically, Yunxian 2 appears to be intermediate between early Homo species and specimens such as Home erectus, Homo ergaster, and the Kabwe and Petralona crania, and later Asian skulls such as Harbin, Dali, and Jinniushan. 

A phylogenetic analysis based upon the new reconstruction of Yunxian 2, found it grouped with a group of Asian specimens including Dali, Jinniushan, Xujiayao, and Hualongdong and the Xiahe and Penghu mandibles, which have together been referred to as the Homo longi clade, based upon the suggestion that the Xujiayao, Xuchang, Xiahe, and Penghu specimens, as well as the Denisovans should be grouped together as a new species, Homo longi (although Feng et al. did not recover the Xuchang specimens as part of this group). Feng et al.'s reconstruction found this clade to be the sister to Homo antecessor, with the Homo longi clade plus Homo antecessor being the sister clade to Homo sapiens. Yunxian 2 is the oldest member of the Homo longi clade as recovered by Feng et al., but not the earliest branching. 

Phylogeny and divergence time of 57 selected fossil operational taxonomic units from the genus Homo. The topology of the tree was the majority consensus of the most parsimonious trees from the parsimony analysis in TNT. The divergence time was inferred from the Bayesian tip-dating analysis in MrBayes 3.2. Branch lengths are proportional to the division age in thousands of years (Ka). Numbers at the internal nodes are the median ages, and the blue bars indicate the 95% highest posterior density interval of the node ages. The red half-brackets on the right indicate the ranges of the Neanderthal, Homo longi, and Homo sapiens clades. The numbers in red highlight the ages of division of the three clades. Yunxian is also highlighted in red. Feng et al (2025).

The term 'Denisovan' was coined for a group of highly fragmentary fossils from the Denisova Cave in the Altai Mountains of Russia. Because of the fragmentary nature of these fossils, it has been possible to determine little about their original morphology, but DNA has been recovered from the specimens, revealing a great deal of genetic information. Studies of mitochondrial DNA from these specimens has suggested that this group branched off from the lineage that led to modern Humans before the Neanderthal line. However, studies based upon nuclear DNA have suggested that Denisovans and Neanderthals were sister groups, with a common ancestor more recent than their last common ancestor with Modern Humans. While the limited amount of data available makes this hard to resolve, Feng et al. suggest that the Denisovans were probably members of the Homo longi clade, with those morphological traits known all consistent with membership of this group. 

The divergence between the ancestors of Neanderthals and those of Modern Humans was for a long time considered to have happened between 700 000 and 500 000 years ago. However, more recent studies incorporating DNA recovered from Neanderthal specimens have suggested a much earlier split. Feng et al.'s analysis suggests that the Homo longi clade emerged as a distinct lineage about 1.2 million years ago, with Homo sapiens first appearing about 1.02 million years ago, around the time when Yunxian 2 was alive. The Homo longi and Homo sapiens clades are recovered as having diverged about 1.32 million years ago, while the Neanderthal clade diverged from the ancestors of these two groups about 1.38 million years ago.

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Nineteen cases of Middle East Respiratory Syndrome Coronavirus infection reported in 2025.

Nineteen cases of Middle East Respiratory Syndrome Coronavirus infection have been reported in 2025 till 21 December, according to a press release issued by the World Health Organization on 24 December. Seventeen of these cases have been reported from Saudi Arabia, and two from France. There have been two fatalities attributed to the disease this year, both in Saudi Arabia. Both cases reported in France were individuals who had recently returned from the Arabian Peninsula. 

Middle East Respiratory Syndrome Coronavirus was first reported in Jordan in 2012, since when there have been 2635 cases reported from 27 countries in all six of the World Heath Organization's regions (Africa, the Americas, Southeast Asia, Europe, the Eastern Mediterranean, and the Western Pacific), with 964 associated fatalities (a case fatality ratio of 37%). However, 84% of these countries (2224 individual infections) have been reported from a single country, Saudi Arabia.

The epidemic curve of Middle East Respiratory Syndrome Coronavirus infections (2635) and deaths (964) reported globally between 2012 and 2025. World Health Organization.

Of the seventeen cases of Middle East Respiratory Syndrome Coronavirus infection reported in 2025, ten were reported in Riyadh Province, three from the city of Tiaf, two from Najran Province, one from Hail Province, and one from the city of Hafr Al-Batin. Details of the French cases, other than that they occurred in individuals who had recently returned from the Arabian Peninsula, are not available.

Geographical distribution of Middle East Respiratory Syndrome Coronavirus infections between 1 January and 21 December 2025. World Health Organization.

Both of the infections reported in France were in the month of December and are still under investigation. These cases bring the total number of reported cases in France to four, with two previous cases in 2013, also in individuals who had recently returned from the Arabian Peninsula.

Middle East Respiratory Syndrome is a viral respiratory infection caused by the Middle East Respiratory Syndrome Coronavirus, a form of positive sense single-strand RNA Virus. Approximately 36% of patients with Middle East Respiratory Syndrome have died, though this may be an overestimate of the true mortality rate, as mild cases of Middle East Respiratory Syndrome Coronavirus may be missed by existing surveillance systems, and the case fatality ratio is calculated based only on laboratory-confirmed cases.

Structure and genomic organisation of a Middle East Respiratory Syndrome Coronavirus Viron. Bleibtreu et al. (2020). 

Humans are infected with Middle East Respiratory Syndrome Coronavirus from direct or indirect contact with Dromedary Camels, which are the natural host and zoonotic source of the Virus. Middle East Respiratory Syndrome Coronavirus has demonstrated the ability to transmit between Humans. So far, non-sustained Human-to-Human transmission has occurred among close contacts and in healthcare settings and outside of the healthcare setting, there has been limited Human-to-Human transmission.

Middle East Respiratory Syndrome Coronavirus infections range from showing no symptoms (asymptomatic) or mild respiratory symptoms, to severe acute respiratory disease and death. A typical presentation of Middle East Respiratory Syndrome disease is fever, cough, and shortness of breath. Pneumonia is a common finding, but not always present. Gastrointestinal symptoms, including diarrhoea, have also been reported. Severe illness can cause respiratory failure that requires mechanical ventilation and support in an intensive care unit. The virus appears to cause more severe disease in older people, persons with weakened immune systems, and those with co-morbidities or chronic diseases such as renal disease, cancer, chronic lung disease, and diabetes.

No vaccine or specific treatment is currently available, although several Middle East Respiratory Syndrome Coronavirus-specific vaccines and therapeutics are in development. Treatment is supportive and based on the patient’s clinical condition and symptoms.

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Three dead as California hit by a series of storms over Christmas period.

Three people have died and many others have been affected by flooding as California has been hit by a series of storms over the Christmas period. A 74-year-old man from Redding, in Shasta County, died on the weekend of 20-21 December 2025, after his car became trapped in floodwaters, despite efforts by local police officers to rescue him. On Monday 22 December a woman in her 70s died after being swept into the sea by a large wave at MacKerricher State Park in Mendocino County. On Wednesday 24 December a 64-year-old man from San Diego was struck by a falling tree.

A car partially buried by a mudslide in San Bernadino County, California. CBS News.

Many areas have been affected by flooding, with some communities in San Bernadino County facing evacuation orders in order to keep them safe. Several flash floods have been reported in Los Angeles County, where 27 cm of rainfall was recorded on Wednesday 24 December, with a large landslip reported in Altadena, on a slope which had been stripped of vegetation by wildfires in January this year. Around 130 households were evacuated due to concerns about flooding and landslides in Los Angeles, mostly in the Pacific Palisades neighbourhood, which was also hit by wildfires in January. Windspeeds gusting in excess of 100 km per hour have been recorded in San Francisco, where waves more than 7 m high have been reported. More than 100 000 people have been left without power due to the storms, mostly in the central part of the state.

The storms have been driven by a phenomenon called an atmospheric river, in which a narrow band of saturated air carries large volumes of moisture for long distances. Such streams typically originate in tropical regions, and typically travel along the boundaries between diverging weather systems. As with other storm systems, once they pass over land they lose momentum, and can be forced upwards by hills or mountains, causing them to cool and deposit their moisture as precipitation, causing high rainfall and often flooding.

A diagrammatic representation of an atmospheric river. National Weather Service/National Atmospheric and Oceanic Organization/Wikimedia Commons.

Atmospheric rivers are a common phenomenon on the west coast of the United States, and a significant driver of local weather conditions. However, these systems are becoming both more common and more severe as a result of the warming climate, which has led to rising temperatures over the tropical Pacific, and subsequently higher levels of atmospheric moisture, combined with a tendency form storm systems and other weather events to form and move much more quickly, making it harder for meteorologists to make long term predictions about where and when such storms will hit.

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