Looking for the Chinguetti Meteorite.

In 1916 a young French army officer called Captain Gaston Ripert reported being taken to see a giant meteorite in the Mauritanian desert, south of Chinguetti. The story is a strange one, with Ripert claiming he was taken blindfolded, at night, on a ten hour Camel ride into the desert, where he observed a huge iron structure 100 m long and 40 m wide, recovering a smaller, 4.5 kg meteorite from its surface. Shortly after returning to Chinguetti, where he was commander of the local Camel corps, Ripert reported that his guide, a local chief, was poisoned, leaving him unable to relocate the site.

The eccentric nature of this story led many people to dismiss it out of hand. It was not unusual for western travellers of the time to make up tales of wild adventure; some even paid ghostwriters to create particularly entertaining tales. However, officers in colonial armies were supposed to refrain from such nonsense, and some aspects of Ripert's story were hard to rectify with the story being complete fiction. 

During the past century a number of expeditions have sought to locate Ripert's meteorite, with the first in 1924, although by this time Ripert was stationed in Cameroon, and could only be communicated with by letters. This meant that the early searches concentrated on the area to the southwest of Chinguetti, although Ripert later clarified that the area he was taken to was probably to the southeast. The French naturalist and explorer Théodore Monod mounted a number of expeditions to find the meteorite, starting in 1934, but was unable to locate it. In the 1950s an expedition by the French army used a declinometer  (instrument for measuring magnetic declination) in a search for the meteorite, without success, and in the 1990s a team from the British TV station Channel 4 used a magnetometer during a search for the meteorite, but took only a few measurements.

Despite all this, there are a number of elements of the story suggest that it was not complete fiction, not the least of this being Ripert's willingness to talk to experts about his journey for the rest of his life. The smaller rock which Ripert recovered did prove to be a meteorite, albeit one which, when subjected to radionuclide analysis in 2001 was shown not to have been part of a larger body (radionuclides form near the surface of asteroids due to a constant bombardment by cosmic rays, but these can only penetrate a little way, so the radionuclides they form are absent from the interior of large bodies). Finally, Ripert reported observing metallic needles protruding from the large meteorite, which he tried unsuccessfully to break off, finding that they were too ductile (able to be deformed without losing toughness) for the tools he had at hand). In 2003, the American geologist and meteorite specialist William Cassidy reported similar ductile metal needles protruding from nickel-rich zones of iron meteorites, but this was clearly unknown to science in 1916.

A fragment of the smaller meteorite brought back by Gaston Ripert in the collection of the Smithsonian National Museum of Natural History. Wikimedia Commons.

In a paper published on the arXiv database at Cornell University on 21 February 2024, Robert Warren  of Salisbury in England, Stephen Warren of the Astrophysics Group at Imperial College London, and Ekaterini Protopapa of the Department of Physics at the University of Oxford, describe the results of a more recent search for the Chinguetti Meteorite, and the prospects for either discovering its existence or proving its non-existence in the future.

Warren et al. began by collating remote-sensing data covering the region from multiple sources; they are reasonably confident that other researchers will have searched Google Earth for signs of the meteorite,  but they also accessed data from other sources, including the Shuttle Radar Topography Mission, the Advanced Land Observing Satellite (ALOS), and Landsat.

Using the reasoning that the only way a 40 m high meteorite could have disappeared in the deserts of Mauritania is for it to have been covered by a sand dune, Warren et al. began by searching for a region of high dunes which could be reached from Chinguetti by Camel in under 10 hours. There are two bands of dunes close to Chinguetti; the Les Boucles field, most of which is within 20 km of the city, and the Batraz field, which is between 40 and 60 km to the southeast. Much of the intervening area is also covered by sand dunes, but these are not large enough to describe an object as that described by Ripert.

Map showing the high sand dunes, greater than 30 m height, to the south of Chinguetti. Warren et al. (2024).

Warren et al. made two trips into the desert from Chinguetta, in the company of experienced local chameliers, one lasting eleven days and one lasting six. They found that Camels typically travel at speeds of between 2.0 and 3.6 km per hour, assuming good terrain, with the maximum speed achieved by unburdened Camels being about 5.0 km per hour. 

However, even assuming that Ripert and his guide were riding Camels unburdened by anything other than themselves, it is unlikely that this maximum speed would have been achieved for 10 hours, because the primary concern of the chameliers is for the welfare of their Camels, which are not only the most important assets they own, but also their only way of getting back to safety should a problem arise. This meant that if Warren et al.'s chameliers expected a journey to take four hours, they would travel for two hours, then give the Camels a three hour break to rest and feed, before completing the journey, something they were quite inflexible about. Neither would they travel in a straight line on anything other than the flattest terrain, but instead would zig-zag to avoid taking the Camels over steps and ledges, and would never take their Camels over the tops of dunes.

Ripert himself mentioned taking several detours during his journey, which makes a journey 50 km in a straight line from Chinguetta even less plausible. However, for the sake of convenience, Warren et al. take the area within 50 km of the city as a search area. This includes the more distant Batraz Dune Field, which Warren et al. consider unlikely, although they do concede that there is a route along a dry river bey which could bring a determined Camel rider this far in 10 hours if breaks were neglected. They also rule out the area of the Les Boucles Dune Field which lies within 10 km of the city, reasoning that Ripert, who was in charge of the local Camel Corps, would have recognised a location in this area. 

A sand dune in the Les Boucles Dune Field to the south of Chinguetta. Bruno Locatelli/Google Maps.

Having defined their search area, Warren et al. then searched their dataset for dunes large enough to have covered the meteorite described by Ripert. According to Ripert's description, the northeastern side of the meteorite was already covered by a dune at the time when he visited. The area is noted for its strong, prevailing winds, which blow northeast to southwest more-or-less constantly all year round, causing sand dunes to migrate in the same direction, and Ripert stated in 1932 that he thought it possible that the meteorite would already have been covered by the dune. Taking Ripert's estimate that the meteorite was 40 m high, it would require a dune more than 40 m high to cover it.

Sand dunes in a desert do not typically stack up against one-another; instead, they are usually discrete structures, with flat spaces between them. Warren et al. identified dunes higher than 30 m high in their remote sensing dataset, in order to give an error of margin, creating a map showing dunes which meet this criterion within the two dune fields. Since dunes are unlikely to have moved more than 100  m since 1916, the meteorite, if buried, must be within 100 m of the western edge of the dune covering it. 

Since a height of 30-40 m is reached within 300-400 m of the western flank of the dunes, it would in theory be possibly for a walk along the western flank of the dunes with a magnetometer (a passive instrument that measures changes in the Earth's magnetic field), and be confident of passing within 500 m of the meteorite, a distance at which it ought to be highly detectable.

Warren et al. also not that a magnetic survey of the area has been carried out by aircraft on behalf of the Mauritanian Ministry of Petroleum Energy and Mines by the Fugro geological surveying company, using funds provided by the World Bank, and this data has subsequently been made available to teams of scientists working on other projects. With this in mind, Warren et al. wrote to the Ministry requesting access to the data, but have yet to receive an answer.

Between 13 and 17 December 2022 Warren et al. carried out a magnetometer survey of the eastern part of the Les Boucles Dune Field on foot, covering the western edges of six large dunes, based upon which they are confident that the presence of a large iron meteorite beneath these dunes can be ruled out. Based upon the time this took, they estimate that a survey of all the potential dunes would require an expedition lasting three weeks. 

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Swiftia phaeton: A new species of deepwater Octocoral from the coast of Mauritania.

Despite being relatively close to the numerous oceanological research institutes of western Europe, the deep waters off northwest coast of Africa have been relatively underexplored compared to those of many other regions of the world. The coast of Mauritania is known to be home to home to the world's largest Coral mound barrier, and their are extensive Coral colonies occupying the marine canyons off the Mauritanian coast, both fuelled by nutrient-rich upwellings from the deep Atlantic ocean along this section of coast.

In a paper published in the journal ZooKeys on 17 June 2022, Íris Sampaio of the Marine Research Department at Senckenberg am Meer, and the University of the Azores, and Lydia Beuck and André Freiwald, also of the Marine Research Department at Senckenberg am Meer, describe a new species of deepwater Octocoral from the coast of Mauritania.

The new species is placed in the genus Swiftia, and given the specific name phaeton, in reference to the PHAETON mission of the Research Vessel Maria S. Merian, which visited the coast of Mauritania, and recovered the first specimens of the species. The Greek Demigod Phaeton (or Phaëthon), is also linked to the region. A son of the Sun-god Apollo, he is supposed to have crashed his father's chariot into the Sahara Desert, burning the Earth and making the area uninhabitable. 

Swiftia phaeton forms simple colonies, either unbranching or with one or two divisions. The colonies are bright red in colour, with polyps densely packed on the branches. Tentacles are yellowish white.

Swiftia phaeton from Mauritania. (A) In situ colony with expanded polyps on coral framework. (B) Colony after ethanol preservation with expanded polyps (holotype SMF 13112). (C) In situ colony with retracted polyps on coral framework. (D) Part of a branch (paratype SMF 13113). (E) Fragment of specimen with anthocodiae slightly expanded (paratype SaM-ID 1566). (F) Polyp and coenenchyme details (paratype SaM-ID 1352). Scale bars are 1 cm (A)–(C) or 300 µm (D)–(F). (A) & (C) Tomas Lundälv/Sven Lovén Center for Marine Infrastructure in Sampaio et al. (2022), (B), (D)-(F) Sampaio et al. (2022).

Swiftia phaeton was found living in Tanoûdêrt Canyon at a depth of 595 m, on the Timiris Mounds at depths of 446-602 m, in the Tioulit Canyon at a depth of 618 m, in the Southern Tamxat Mound Complex at a depth of 450 m, and on the Central Tamxat Mound Complex at a depth of 486 m.

Map showing MSM 16/3 ‘PHAETON’ ROV dive locations along the Mauritanian slope. Location names and GeoB 14 stations (sta.): grey, canyons; black, Coral mounds; orange, Scleractinian distributions. Sampaio et al. (2022).

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The Cabeço da Amoreira burial: An Early Modern Era West African buried in a Mesolithic shell midden in Portugal.

The Tagus and Sado valleys of central Portugal contain numerous shell middens, dating back to the Late Mesolithic, roughly 6500 to 5000 years ago. As well as depositories for waste shells, these sites were used as burial grounds by the people who made them. A number of these sites were excavated by archaeologists in the 1930s, producing a series of sets of Human remains, buried within the middens without grave goods. One site, Cabeço da Amoreira at Muge in the Tagus Valley yielded an individual noted at the time as being both notably taller and better preserved than others recovered from such sites. More recently, scientists working on a database of Mesolithic European genomes have begun to sequence individuals from these Mesolithic Portuguese sites, including the Cabeço da Amoreira individual, in the process of which they found that this individual was not closely related to other individuals from Mesolithic burials in Portugal, or elsewhere in Europe, but rather appeared to be of African descent.

In a paper published in the Journal of Archaeological Science: Reports on 21 February 2022, Rita Peyroteo-Stjerna of Human Evolution at Uppsala University and the Centro de Arqueologia da Universidade de Lisboa, Luciana Simões, also of Human Evolution at Uppsala University, Ricardo Fernandes of the Department of Archaeology at the Max Planck Institute for the Science of Human History, the School of Archaeology at the University of Oxford, and the Faculty of Arts at Masaryk University, independent researcher Gonçalo Lopes, and Torsten Günther and Mattias Jakobsson, again of Human Evolution at Uppsala University, present the results of the follow up study which used multiple lines of enquiry to determine the origin of the Cabeço da Amoreira individual.

 

Location of Cabeço da Amoreira shell midden (indicated by the star), Muge, Tagus valley, Portugal. Peyroteo-Stjerna et al. (2022).

Radiocarbon dating of material from the Cabeço da Amoreira site, including bone, charcoal and shells, have produced dates of between 6500 and 5000 BC, consistent with a Mesolithic origin for the site, however, radiocarbon dating of collagen from the individual buried at the site yielded dates between 1529 and 1763 AD, and probably between 1631 and 1793, consistent with an Early Modern origin. 

Relationships between Early Modern Europe and Africa were dominated by the trans-Atlantic slave trade, which saw millions of people taken from Africa and shipped to European colonies in the New World, and to a lesser extent Europe itself. Portugal is estimated to have directly imported 2-3000 African slaves per year between the fifteenth and nineteenth centuries. Most of these remained enslaved their whole lives, though some were freed and able to live relatively independent lives, albeit very much at the bottom of the social scale. 

Because mitochondrial DNA is found in the mitochondria, organelles outside the cell nucleus, it is passed directly from mother to child without being sexually recombined each generation, enabling precise estimations of when individuals shared common ancestors, at least through the female line; this is known as the female haplogroup. It is also possible to trace direct ancestry through the male line, using DNA from the Y chromosome, which is passed directly from father to son without sexual recombination; this is known as the male haplogroup. Since everyone has mitochondria, it is possible to determine the female haplogroup of all Humans, but generally only males have a Y chromosome and can be assigned to a male haplogroup.

Genetic analysis of the Cabeço da Amoreira individual established that he had a Y chromosome, indicating that he was male. It was also possible to determine both his male haplogroup. He was found to belong to the E1b1a male haplogroup, which is the most widespread in sub-Saharan Africa, being commonly found in Nigeria, Congo, Cameroon, Gabon, Guinea-Bissau, and among Bantu-speakers in Southern Africa.

A principle component analysis based upon his entire recoverable genome revealed that Cabeço da Amoreira man showed a greater genomic similarity to West Africans than to other populations, and in particular, to people of Gambian or Mandinka origin. 

 

(A) Principal component analysis. Worldwide modern populations (circles coloured according to continent) and Cabeço da Amoreira man projected as a yellow, red outlined diamond. (B) Geographic distribution of the genetic affinity of the studied individual with modern African populations, measured by outgroup-f₃. The two highest f₃ scores are depicted with diamonds. Peyroteo-Stjerna et al. (2022).

Peyroteo-Stjerna et al. next looked for alleles (gene variants) associated with sub-Saharan populations, finding that Cabeço da Amoreira man had a number of alleles which would further support an African origin, notably the FY*B allele, which is associated with resilience to Malaria, and a number of skin pigmentation alleles, namely MFSD12 rs10424065; DDB1 rs11230664; OCA2 rs1800404; SLC45A2 rs16891982; and HERC2 rs6497271, which are more commonly associated with sub-Saharan African populations than with Europeans (skin pigmentation is complicated, genetically speaking, and it is not possible to directly determine someone's exact skin tone from their genome at the current time, but it is possible to associate allele abundances with specific populations). Cabeço da Amoreira man also lacked the alleles for lactase persistence (i.e. retaining the ability to digest milk into adult life), sugesting that he was lactose intolerant, something more common in Africans than Europeans.

A stable isotope analysis for carbon and oxygen isotopes, based upon bone collagen from Cabeço da Amoreira man, suggested that when he was growing up his diet comprised largely C₄ Plants, supplemented with seafood. A diet of C₄ Plants is not at all typical for Portugal (or elsewhere in Europe) in the Early Modern period, although it would have been common in parts of West Africa, notably the Sahel Region (which reaches the coast in the Senegambia region and southern Mauritania), where the principal crops for the time would have been Sorghum and Millet, both of which are C₄ Plants. Further south, in the West African forest zone, the principal crops were Rice (a C₄ Plant) in the west and a more mixed vegecultural diet (also based around C₄ Plants) in the east. Therefore, the C₄ Plant component of Cabeço da Amoreira man's diet makes it likely that he came from the Sahel region, and the seafood component further ties him to the Senegambia and Mauritania region.

 

Estimated area of origin of Cabeço da Amoreira man (mug019) in West Africa and place of burial in Portugal. Traditional plant food-producing systems in West Africa. Peyroteo-Stjerna et al. (2022).

Around 35 000 slaves were brought to Portugal from Africa between 1514 and 1866. Records of these movements are fairly complete after 1750, but older records are somewhat patchy, making the origin of Cabeço da Amoreira man difficult to reconstruct in this way. However, it is known that slaves were brought to Portugal from predominantly from Guinea-Bissau and The Gambia, with smaller numbers arriving from the Cape Verde islands, Princes Island and São Tomé, Bance Island (Sierra Leone), the Gold Coast (Ghana), Senegal and Whydah (on the coast of modern Benin). 

Most slaves in Portugal during this period would have been baptised as Christians, and buried in Christian burial grounds. However, there are records of slaves being buried in other ways, including by roadsides, in wastelands or in Olive groves. The Church generally kept good records of births, deaths, marriages, and baptisms during this period, for all social classes including slaves, which offered some hope of discovering the identity of Cabeço da Amoreira man. Peyroteo-Stjerna et al. were able to identify two deaths of interest in the Cabeço da Amoreira area in the seventeenth century, the first of an unnamed slave on 5 May 1633, for whom no burial location is listed, and the second of the murder of a man named João at Arneiro da Amoreira on 1 November 1676; João is described as being brown skinned, which may indicate that he was of mixed origins, but he was buried in a churchyard, so presumably was not Cabeço da Amoreira man.

One notable feature of the Cabeço da Amoreira burial is that the body does not appear to have been buried hastily, but rather laying upon a bed of sand which had been used to line the grave, something not seen in Mesolithic shell midden burials (the difference was noted at the time of excavation, but the significance of this, understandably, was not realised).This implies that the burial at this location was planned and carefully executed, rather than being the hurried disposal of the body of a slave or murder victim.

Shell midden burials, both ancient and modern, are known from the Senegambia region, and are still sometimes practiced among Serer fishermen in the Saloum Delta. Here, some families maintain temporary settlements on islands deep within the delta, which are used for four-to-five months each year, when shellfish are harvested. Since these sites are essentially located on shifting sandbanks, the shell middens that build up their form stable hardgrounds, which can be used for purposed such as supporting structures and burying anyone who dies while the temporary villages are in use.

 

Modern cemetery on a shell midden, at Fadiouth in the Saloum Delta, Senegal. Hardy et al. (2015).

This does not unequivocally tie the Cabeço da Amoreira burial to the Senegambia region, but does create a plausible scenario in which members of a community transplanted to Portugal, who had practiced shell midden burials in their homeland, might have chosen to recreate the practice in their new environment.

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Thousands of Great White Pelicans die in Avian Influenza outbreak in Senegal and Mauritania.

Nearly 2500 Pelicans died in late January in two National Parks on the border of Senegal and Mauritania as a result of an outbreak of the Highly Pathogenic Avian Influenza, according to a press release issued by BirdLife International on 4 March 2021. In late January 2021, 750 Great white pelicans were found dead in the Djoudj Bird Sanctuary, a remote pocket of wetlands and a UNESCO World Heritage site in northern Senegal, which provide a rest stop for millions of migratory birds every year. This was followed by the death of 1642 pelican chicks and two dozen adult pelicans in Diawling National Park in Mauritania bordering northern Senegal, which hosts over 250 bird species. According to national authorities, these deaths were attributed to the outbreak of the Highly Pathogenic Avian Influenza.

Following the outbreak, the national governments of Senegal and Mauritania are coordinating an emergency response. Nature Mauritania and the collaborating organisation in Senegal Nature Communautés Développement are at the forefront of this response. Nature Mauritania is raising awareness of Highly Pathogenic Avian Influenza in communities in Diawling, and is leading a surveillance committee set up in Banc d’Arguin to monitor any outbreak of the disease. Nature Communautés Développement in Senegal has activated its network of members and volunteers to monitor and report any death of birds across the country. While no further Highly Pathogenic Avian Influenza outbreak has been reported in the two countries, epidemiological surveillance is ongoing in other sites including parks and reserves. Increased collaboration and information sharing between the two countries is ongoing.

 

A pod of Great white pelicans in Djoudj Bird Sanctuary in Senegal. Lewis Kihumba/Geoffroy Citegetse. Birdlife International.

More importantly, a Highly Pathogenic Avian Influenza Action Plan has been developed in Senegal and the focus is now on its implementation. Three sub-committees on Epidemiology, Surveillance and Biosecurity have been established. Currently, meetings are being held with donors and technical partners to finance this action plan. Furthermore, epidemiological monitoring of wild and domestic birds, and active surveillance in marketplaces and ornithological sites, are ongoing. Capacity building to ensure an effective response is also being carried out. The Senegalese coordinating team is currently undergoing training on Incident Management Systems.

'The Great White Pelican is a migratory bird with a large range in Africa. Monitoring the key sites used by the species in West Africa is key to prevent the spread of the Highly Pathogenic Avian Influenza. Transboundary cooperation and involvement of communities is essential in this response' stated Djibril Diallo, Executive Director of Nature Mauritania.

Cross-border meetings between authorities in Senegal and Mauritania are also taking place to ensure coordination between the two countries. BirdLife International and its partners will continue supporting national authorities in Mauritania and Senegal to implement the Highly Pathogenic Avian Influenza Action Plan and enhance monitoring to prevent future outbreaks.

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Chinese rocket crashes into the Atlantic Ocean off the coast of Mauritania.

A 30 m long, 17-8 tonne Chinese rocket-stage fell into the Atlantic Ocean off the coast of Mauritania, slightly after 3.30 pm GMT on Monday 11 May 2020, from the Wenchang launch centre on Hainan Island in southern China. The piece of space junk was the main rocket stage of a Long March 5B heavy launcher which took off on Tuesday 5 May. The rocket was initially lifted from the ground by three smaller kerosene fuelled rocket boosters, then powered the main lift of the spacecraft by using a cryogenic hydrogen system. The rocket delivered a prototype manned crew capsule (without any crew) into orbit, and was expected to burn up high in the atmosphere as it fell back. However, the much of the body appears to have survived, and was tracked by the US Air Force, passing over New York about 15 minutes before eventually vanishing off the coast of Mauritania.

The trajectory of the Long March 5 rocket-booster (orange line), and it's last known location. Jonathan McDowell/Twitter.

Pieces of space junk re-entering the atmosphere, and even reaching the ground (or sea) are not that unusual, but objects of this size are somewhat rare, with the last object of this size having been the 39 tonne Soviet Salyut 7 Space Station in February 1991, which crashed into the Pacific Ocean southern Pacific Ocean. The Colombia Space Shuttle, which was disintegrated during re-entry in February 2003 is not usually counted as 'space junk' as it was manned, but weighed 2000 tonnes, so this could be considered the largest such object.The Russian Fobos-Grunt Probe, which fell into the Pacific Ocean in January 2012, after an unsuccessful launch in November 2011, weighed about 13 tonnes.

The re-entry orf the Long March stage was planned, but it's survival into the lower atmosphere was unexpected, as it was essentially a hollow tube. It is possible that only the rocket engines survived re-entry, reducing the size of the object at impact. In either event, a returning rocket launcher presents a far lower risk to anyone on the ground than an asteroid of similar mass, as its velocity is much lower, with asteroids travelling far faster due to their orbital velocity, as their trajectory seldom matches that of the Earth.

The launch of the Long March 5B heavy launcher from Hainan Island on 5 May 2020. CNN.

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Calliostoma bullatum: An extinct Pleistocene Snail from northern Sicily found alive on the coast of Mauritania.

The Calliostomatid Snail Calliostoma bullatum is known from Early-Middle Pleistocene (1.8-0.8 million-year-old) deposits around Messina on the northern coast of Sicily, Italy. It is notably larger than any living species in the genus Calliostoma, with a shell reaching about 34 mm in both height and width. Like living members of the genus it is interpreted as having been a deepwater species, associated with the deepwater mound forming colonial Corals Lophelia pertusa and Madrepora oculata, both of which are still extant, though Calliostoma bullatum has not been found in any of the numerous surveys of deepwater Coral Mounds carried out in the Mediterranean and Atlantic, and has therefore been considered to be extinct until now.

In a paper published in the journal Zootaxa on 4 June 2019, Leon Hoffman, Lydia Beuck, and Bart van Heugten of the Marine Research Department at Senckenberg am Meer, Marc Lavaleye of the Royal Netherlands Institute for Sea Research, and André Freiwald, also of the Marine Research Department at Senckenberg am Meer and of Bremen University, describe the discovery of Calliostoma bullatum living on deepwater Coral Mounds on the coast of Mauritania.

The species was found by a remotely operated vehicle from the Research Vessel Maria S. Merian, during a visit to the area in 2010. It was found at a number of locations on the Mauritanian coast; in the Tanoûdêrt Canyon, the Nouamghar Canyon, the Inchiri Canyon, Timiris Mound Complex, the Tioulit Canyon, the Banda Mound Complex, the Tamxat Mound Complex, and the Tiguent Mound Complex. All live specimens were found at depths of between 450 and 652 m, though dead specimens (shells) were observed at depths of as little as 414 m. It was found in association with mound reefs formed by the colonial Corals Lophelia pertusa and Madrepora oculata, the same environment as fossil specimens of the same species. Such Coral Mounds have been extensively surveyed along the Atlantic Coast of Europe, the Mediterranean, the Atlantic Coast of Morocco and Western Sahara, and the islands and seamounts of the northeast Atlantic, without Calliostoma bullatum having previously been identified, suggesting that it is absent from these areas, though the area to the south, along the coast of the Senegambia Region and beyond, is less well surveyed, so the species might be present here.

Calliostoma bullatum on various substrates. (9) Grazing on Hydroids. (10) Elongated, muscular foot supports feeding on polyp tissue (Madrepora oculata). Operculum and dorsal groove on foot indicated by arrow. (11) Muscular foot enables elevation of body above substrate (live Lophelia pertusa). Epipodial sense organs spread directly below the shell (arrow). (12) Feeding on apical portions of a live Madrepora oculata. (13) Two individuals feeding on Lophelia pertusa tissue; note the grazing tracks showing the bare, white coral skeleton devoid of polyp tissue in contrast to the orange to pale-pinkish live portions. (14) Three individuals of different sizes all feeding on epibionts of Lophelia pertusa framework; note the grazing traces on adjacent live Lophelia pertusa portions (see arrow). Tomas Lundälv/Sven Lovén Centre for Marine Infrastructure Tjärnö/University of Gothenburg in Hoffman et al. (2019).

Adult specimens of both Pleistocene and Modern Calliostoma bullatum have about seven slightly convex whorls (excluding the protoconch). These whorls have fine spiral striation, with Modern specimens having more striations than Pleistocene specimens, however striation number is known to vary between populations of other extant members of the genus Calliostoma, so this variation is not considered a bar to classifying the Modern and Pleistocene specimens as the same species.

(7) Specimen of Modern Calliostoma bullatum collected from the coast of Mauritania. (8) Fossil specimen collected from Pleistocene of northern Sicily in 1844, and illustrated by Rodolfo Amando Philippi. Hoffman et al. (2019).

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