Wednesday 31 May 2023

Estimating biodiversity in the Clarion-Clipperton Zone.

The Clarion-Clipperton Zone is an area of the Pacific seafloor bounded by the Clarion and Clipperton fracture zones to the north and south, and the 115°W and 160°W longitude lines. It has an area of about 6 million km², making it roughly twice the size of India, and is located between Hawai'i, Kiribati, and Mexico, but lies entirely outside the jurisdiction of any nation. Throughout this region the seafloor is between 4000 and 6000 m deep, and mostly covered with muddy sediments with a scattering of Potato-sized polymetalic nodules, making the zone attractive to prospective deep-sea miners. The seafloor here is known to host a diverse community of benthic organisms, albeit at a much lower density than is found on the continental shelves or in coastal regions.

The Clarion-Clipperton Zone has been explored for mineral extraction since the 1960s, a process formalized by the formation of the International Seabed Authority in the 1980s, although the possibility of actual mining operations is only becoming possible now. There are currently 17 mining concessions granted within the Clarion-Clipperton Zone, covering an area of about 1.2 million km². 

Despite decades of exploration work being carried out within the Clarion-Clipperton Zone, very little taxonomic work has been carried out, with large-scale environmental surveys in the 1970s, 1980s and 1990s producing lists of informally named taxa only; i.e. differentiated by morphological or molecular data, but not formally described. This presents challenges for anyone trying to understand the biodiversity of the region, particularly as deep ocean benthic environments are known to be rich in cryptic species, as the constraints of the environment push members of different taxonomic groups towards similar morphologies and lifestyles.

To make matters worse, the data that has been collected isn't to any method, with sampling and data recording being carried out in different ways in different studies. Furthermore, many studies that have been carried out within the Clarion-Clipperton Zone have concentrated on particular taxa, ecological groups or size classes, and have usually covered only small parts of the zone. This greatly hampers the establishment of any overall understanding of biodiversity within the region, making to almost impossible to come up with a coherent environment management policy plan. Without any meaningful understanding of the biodiversity of the area, it is essentially impossible to calculate the range or environmental requirements of individual species, nor to tell which species are common and widespread and which are rare and tied to very specific environments. 

In a paper published in the journal Current Biology on 25 May 2023, Muriel Rabone of the Deep-Sea Systematics and Ecology Group at the Natural History MuseumJoris Wiethase of the Department of Biology of the University of YorkErik Simon-Lledo of the National Oceanography CentreAidan Emery, also of the Deep-Sea Systematics and Ecology Group at the Natural History Museum, Dan Jones, also of the National Oceanography Centre, Thomas Dahlgren, of the Department of Marine Sciences at the University of Gothenburg, and the Norwegian Research CentreGuadalupe Bribiesca-Contreras, again of the Deep-Sea Systematics and Ecology Group at the Natural History Museum, Helena Wiklund, again of the Deep-Sea Systematics and Ecology Group at the Natural History Museum and the Norwegian Research Centre, Tammy Horton, again of the National Oceanography Centre, and Adrian Glover, once again of the Deep-Sea Systematics and Ecology Group at the Natural History Museum, present a synthesis of Metazoan biodiversity within the Clarion-Clipperton Zone, aimed to convey the best currently available information to all stakeholders, ahead of the start of any mining operation within the zone.

Rabone et al. synthesized data from seven different data sources, producing over 100 000 individual records. Although these were assembled over several decades, the majority of the taxonomic work is recent, and much less than five years old. A total of 219 taxa new to science (including species, genera, and families) have been described from the Clarion-Clipperton Zone, again mostly in the recent past; only seven were described prior to the year 2000. The checklist of Animal species assembled by Rabone et al. includes 436 species found within the Clarion-Clipperton Zone, including 185 which were first described from within the zone (31 new genera and 3 new families were also described from within the zone). Of these 185 species, only six have subsequently been discovered living in other areas; two Sea Cucumbers, a Nematode, a Carnivorous Sponge, a Crinoid, and an Antipatharian Coral.

All geolocated published records of benthic Metazoa from the literature and databases Areas of Particular Environmental Interest and exploration mining contract areas, both active and reserved, are shown in outline. The type localities of all species described from the Clarion-Clipperton Zone to date are also shown (185 in total). Rabone et al. (2023).

A total of 27 phyla of Animals have been recorded in the Clarion-Clipperton Zone, as well as 49 classes, 163 orders, 501 families, and 1119 genera. Of the 436 Animals identified to species level, 185 (i.e. 42%) have been identified on the basis of both molecular and morphological data, with 217 (50%) identified only by their morphology. The remaining 34 species were listed with no method of identification given. Of the species described from the Clarion-Clipperton Zone, 51% were identified solely on the basis of morphology; this rises to 86% for meiofauna (species larger than 150 μm but smaller than 300 μm). For the most abundant groups within the Clarion-Clipperton Zone, Tanaid and Isopod Crustaceans and Polychaete Worms, 23% of the species identified were originally described from outside the zone, including some species from other ocean basins. A total of 5367 unnamed species were recorded, although 3.9% of these are species Rabone et al. believe to have been named erroneously; if these are taken out of the equation the number is 5142.

Rates of species descriptions in the Clarion-Clipperton Zone; proportion of species diversity in the Clarion-Clipperton Zone that is undescribed. (A) Rates of new descriptions and publications in the Clarion-Clipperton Zone. Cumulative totals of new taxa (families, genera, and species combined) and new species described from the Clarion-Clipperton Zone and taxonomic publications per year, over the period 1980–2022. Yearly totals of new descriptions also shown. (B) Proportion of recorded benthic Metazoan diversity from the Clarion-Clipperton Zone that is undescribed: named species recorded in red (both those described from the Clarion-Clipperton Zone and elsewhere), unnamed species shown in blue (‘unassigned’ are records not identified to phylum). Depictions of some of the new Clarion-Clipperton Zone species by phyla: Annelida, Neanthes goodayi Drennan; Arthropoda, Siphonis aurreus; Brachiopoda, Oceanithyris juveniformis; Bryozoa, Pandanipora helix; Cnidaria, Abyssopathes anomala; Echinodermata, Psychropotes dyscrita; Kinorhyncha, Meristoderes taro; Loricifera, Fafnirloricus polymetallicus; Mollusca, Ledella knudseni; Nematoda, Odetenema gesarae; Porifera, Chaunoplectella megapora; and Tardigrada, Moebjergarctus clarionclippertonensis. Rabone et al. (2023).

Based upon identified species, the most abundant taxa in the Clarion-Clipperton Zone are the Arthropoda, comprising 27% of the total, followed by the Annelida, 18%, Nematoda, 16%, Echinodermata, 13%, and Porifera, 7%. The proportions appear to be similar for unnamed species, albeit with a slightly higher proportion of Annelid Worms. According to the World Register of Deep-Sea Species (part of the World Register of Marine Species) there are currently 36 579 named species of Animal known to live at depths of greater than 500 m, of which 31% belong to the Phylum Arthropoda, 17% to the Phylum Mollusca, 15% to the Phylum Chordata, and 10% each to the phyla Annelida and Echinodermata. Thus the Clarion-Clipperton Zone appears to have a significantly higher proportion of Annelid, Nematode, and Echinoderm species than the deep ocean as a whole, and slightly higher proportions of Sponges and Bryozoans than the deep ocean as a whole. Conversely, the Clarion-Clipperton Zone has a lower proportion of Molluscs, particularly Gastropods, and Chordates, particularly Teleost Fish. Also notable is that Holothurans (Sea Cucumbers) make up a higher proportion of the total number of Echinoderm species in the Clarion-Clipperton Zone, while Asteroids (Starfish) and Ophiuroids (Brittle Stars) are less numerous. There are also groups, such as the Pycnogonids (Sea Spiders) for which there are no recorded named species within the Clarion-Clipperton Zone, although unnamed species are known.

Classed by size, 50% of identified species from the Clarion-Clipperton Zone are macrofauna (larger than 300 μm but smaller than 10 mm), 28% are megafauna (larger than 10 mm), and 22% are meiofauna (smaller than 300 μm but larger than 150 μm). This reflects the nature of studies carried out in the area, with 46% concentrating on macrofauna, 30% on megafauna, and 22% on meiofauna, What is notable about the Clarion-Clipperton Zone is the nature of the substrate, with the combination of soft mud and hard nodules, meaning that 14% of named species and 13% of unnamed species are hard-substrate species living on nodules, while the remainder are soft substrate species living on or in the mud. Several species of megafauna (Cnidarians and Sponges) have recently been described from nodules in the Clarion-Clipperton Zone, though there have only been two quantitative studies of macrofaunal nodule dwellers to date, revealing that the majority of these are undescribed Sponges and Bryozoans. One monograph on nodule Bryozoans in the Clarion-Clipperton Zone has been published, which described sixteen new species, nine new genera, and two new families. 

Fauna from the Clarion-Clipperton Zone. (A)–(J) All fauna are species described from the region and illustrating a range of phyla and size classes. Row 1 (A) the Sea Cucumber, Psychropotes dyscrita , commonly known as the ‘Gummy Squirrel’ (scale bar is 5 cm); (B) the Primnoid Coral, Abyssoprimnoa gemina, (scale bar is 5 mm); (C) the Antipatharian Coral, Abyssopathes anomala, (scale bar is 2 cm); and (D) the Hexactinellid Sponge, Sympagella clippertonae, (scale bar is 1 cm). Row 2, (E) the Cyclostomatid Bryozoan, Pandanipora helix, (scale bar is 500 μm); (F) the Isopod, Macrostylis metallicola, (scale bar is 0.2 mm); (G) the Polychaete, Neanthes goodayi, and (H) the Mollusc, Ledella knudseni, (scale bar is 0.5 mm). Row 3, (I) the Nematode, Odetenema gesarae, (scale bar is 100 μm); (J) the Kinorhynch, Meristoderes taro, (scale bar is 10 μm); (K) the Loriciferan, Fafnirloricus polymetallicus, (scale bar is 100 μm), and (L) the Copepod, Siphonis aurreus, (scale bar is 100 μm), Rabone et al. (2023).

Rabone et al. used several different mathematical models to attempt to predict the total number of Animal species within the Clarion-Clipperton Zone, producing answers which ranged from 6109 to 8514, with between 947 and 1034 genera, and 406-544 families. Thus, although there are clearly many unidentified species left within the zone, the picture appears to be much more complete for higher level taxonomic categories.

Rabone et al. estimate that 92% of species within the Clarion-Clipperton Zone remain unidentified. The proportion of unidentified species is thought to vary considerably from group to group, with 99.4% of Taneid Crustacean species though to be unidentified, along with 96.6% of Isopod Crustaceans and 87% of Polychaete Worms. An estimate of 92% of species being unidentified is also in line with higher estimates for the proportion of unidentified species in the total ocean.

Sampling efforts cross the Clarion-Clipperton Zone have note been even, with the majority of studies having been carried out in the central and eastern parts of the area, while portions of the zone remain almost totally unexplored. There is a similar unevenness in the depth of sampling, with the majority of sampling having taken place at depths of about 4200 m and about 5000 m. Both the depth and geographical data relate to areas where mining exploration contracts have been granted, mostly in the east-central part of the zone. Data on numbers do not exist for all recorded species, but where they do, 37% are known only from a single specimen, which implies significant undersampling. Again, 91% of the single specimen species have been recorded in areas where mining concessions have been granted, with the area known from Areas of Particular Environmental Interest. Overall, 95% of species recorded (named and unnamed) are unknown in the declared Areas of Particular Environmental Interest.

Heatmap of sampling effort as the density of unique sampling sites. Sampling effort is displayed as two-degree polygons. Rabone et al. (2023).

Rabone et al.'s study provides an estimate of the known and unknown species richness for benthic Animals across the Clarion-Clipperton Zone. This shows sampling to be very incomplete at the species level, but likely to be complete or very nearly complete at the family level. 

Density of sampling by depth. Number of samples by depth, grouped by 10 sample quantiles, all taxa combined. Rabone et al. (2023).

Diversity estimates can be seriously distorted when specimens of the same species are recorded as different species, a problem Rabone et al. believe was present in one of the sources they consulted,, the DeepData Database of the International Seabed Authority, where they suggest about a quarter of records represent duplicates. Further duplications could potentially be present and undetected within the remaining data.

Rabone et al. note that some regions of and habitats within the Clarion-Clipperton Zone remain almost totally unsampled. There have been, for example, only six studies of rocky outcrops and seamounts within the zone, habitats which are known to typically have very different faunas to other deep sea environments. The Clarion-Clipperton Zone is a highly variable area compared to much of the oceans' abyssal plains, with numerous rocky outcrops, and extensive fields of polymetallic nodules. Such a diverse environment ought to support a diverse community of organisms, with a lack of sampling almost certainly leading to a significant deficiency in the available data on biodiversity in the region.

A number of other factors could potentially cause estimates of species richness to be inflated or underestimated. Notably, within the Clarion-Clipperton Zone, many species have been recorded by informal names only, allowing for multiple synonyms for a single species, and variation in naming practices over time. A proportion of the informal names within the consulted data sources will no doubt be wrong; but it is impossible to do more that estimate this inaccuracy.

For the most abundant groups within the Clarion-Clipperton Zone, Tanaid and Isopod Crustaceans, 23% of identified species have type localities outside the zone, many within other ocean basins. These groups are known to include many widespread species, but it is still quite possible that this record could include many cryptic species (i.e. species which appear morphologically identical, but which are genetically distinct) or species complexes (groups of closely related cryptic species), which are known to be particularly prevalent in the deep oceans. Resolving this would require genetic sampling of both specimens from the type locality and the Clarion-Clipperton Zone population(s); without this the diversity of these groups may be underestimated by 20-25%. Most of the new species described from within the Clarion-Clipperton Zone have been described since the advent of molecular taxonomy as a standard method, but 51% are named from morphological data only. This is particularly true for smaller species, with 86% of meiofaunal species described from the Clarion-Clipperton Zone described only on the basis of morphological data. 

Rabone et al. suspect that their figure of 92% of species being unidentified within the Clarion-Clipperton Zone includes an overestimation of the number of species due to different informal names being used for the same species, but an underestimation of the number of species due to undersampling of some regions, and the presence of cryptic species. 

Rabone et al's study produces a species composition for the Clarion-Clipperton Zone with differs from the World Register of Deep-Sea Species estimate for the deep ocean, even at phylum level. Some of the trends produced in the study are likely to be real, such as the higher diversity of Sea Cucumbers in the World Register of Deep-Sea Species than in the deep ocean as a whole, but others are likely to be the result of problems such as uneven sampling within the zone and a shortage of experts working on some taxonomic groups. Rabone et al. also note that the majority of species identified within the Clarion-Clipperton Zone, both named and unnamed, fall into the macrofauna category, which has been the subject of the most studies within the region. Megafauna, which are hard to sample using remote-operated vehicles, are rarely collected, and therefore seldom identified. Meiofauna are thought to make up the majority of the biomass of organisms in the deep sea, but are also thought to be significantly undersampled. This situation is not unique to the Clarion-Clipperton Zone, and the World Register of Deep-Sea Species probably also contains significant biases, given the lack of sampling across much of the deep ocean floor.

Very few estimates of biodiversity across large areas of the deep ocean floor have been carried out. A study of the deep sea floor of the Southern Ocean found 674 species of Isopod Crustacean, 87% of which were new to science. Rabone et al. estimate that 96% of Isopod species within the Clarion-Clipperton Zone will be undescribed from elsewhere, i.e. the 23 species already described from within the zone, plus an estimated 474 species yet to be described. Estimates of the total number of marine Animal species range from 300 000 (likely to be a significant underestimate) to 10 million (likely to be a significant overestimate). Rabone et al. estimate the proportion of undescribed species within the Clarion-Clipperton Zone at 92%, while the number for the total deep ocean has been estimated at 87%, a comparable figure. The named species within the Clarion-Clipperton Zone currently represent about 1% of the total estimated deep sea biodiversity for the planet, while the total number of species probably represents about 15% of that total.

The biodiversity of the Clarion-Clipperton Zone is currently significantly under-described. Thirty one new genera and three new families have been described from the zone to date, and Rabone et al. are aware of several new general and at least one new family of Animals- awaiting description from samples collected within the zone. The area clearly contains a significant amount of unique evolutionary lineages. The Clarion-Clipperton Zone is known to be home to significant Echinoderm novelty not known from elsewhere, and the same is probably true of other groups. Life histories unknown from elsewhere have also been recorded within the Clarion-Clipperton Zone, including organisms associated with the stalks of Sponges, as well as Nematodes, Isopods, and Polychaetes from groups otherwise associated with infaunal sediment-dwelling lifestyles which have adapted to live on the hard surfaces of polymetallic nodules. Suspension feeders are also particularly likely to be associated with nodules, with 60-80% of megafauna (the size range dominated by suspension feeders) within the Clarion-Clipperton Zone living on the surface of nodules. How these nodule-dwelling species (and species living in the nearby sediments) would be affected by deep-sea mining efforts targeting the nodules has never been the subject of any specific study. Little is known about the life-histories of these nodule-dwelling organisms, and any such study is likely to be extremely difficult, given that a third of such species have been observed only once.

Studies of individual taxa within the Clarion-Clipperton Zone have estimated that the proportion of undescribed taxa is in excess of 80%. Rabone et al.'s study provides the first estimate of the area's total biodiversity, and estimates the number of undescribed species to be between 88% and 92%. Despite decades of study in the region, taxonomic studies have only recently begun, leaving much work to be completed, something which Rabone et al. should be treated as a matter of some urgency, given the likelihood of mining operations commencing in the zone in the near future. Biodiversity is often assumed to be low in deep marine environments, but this assumption is at least partly driven by low sampling levels rather than low diversity. The United Nations Convention on the Law of the Sea states that marine mining efforts should cause 'no serious harm', but this term is not defined, and in the absence of reliable data on deep marine ecosystems, could easily become meaningless. 

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Monday 29 May 2023

Nemacheilus pullus: A new species of Stone Loach from central Laos.

Stone Loaches, Nemacheilidae, are freshwater Cypriniform Fish found throughout Eurasia, with one genus occurring in Ethiopia. They favour fast moving stretches of small streams, but are occasionally found in larger rivers, and even caves. The group currently contains about valid 790 species in 53 genera, with new species being described on a regular basis, particularly from Southeast Asia. The genus Nemacheilus currently includes 36 species from the Chao Phraya, Mae Khlong, and Mekong river drainages, the Malay Peninsula, and the islands of Sumatra, Java and Borneo. Members of this genus tend to be found in streams and rivers with slow to moderate flows and sand, gravel, or pebble bottoms.

In a paper published in the Raffles Bulletin of Zoology on 20 February 2023, Maurice Kottelat of the Lee KongChian Natural History Museum at the National University of Singapore, describes a new species of Nemacheilus from central Laos.

The new species is named Nemacheilus pullus, where 'pullus' is intended to mean dark yellow to blackish. The species is described from populations living in the Nam Ngiep and Nam Xan watersheds of the the Mekong drainage in central Laos, which were previously assigned to the species Nemacheilus platiceps.

Nemacheilus pullus, Laos: Mekong drainage: Nam Ngiep watershed; (a) CMK 27518, paratype, male, 37.7 mm; (b) MHNG 2787.091, holotype, male, 41.5 mm; (c) CMK 27518, paratype, female, 64.1 mm. Note that in b the specimen is slightly tilted laterally and the eye appears more distant from the dorsal profile than in reality. Kottelat (2023).

Nemacheilus pullus shares with Nemacheilus platiceps an incomplete lateral line, whereas in almost all other members of the genus the lateral line is complete. However Nemacheilus pullus lacks the clear flank bars of Nemacheilus platiceps, instead being a plain yellowish grey in colour (juveniles, and some adult females, do have faint bars, but these are much less clear than in Nemacheilus platiceps). 

Nemacheilus platiceps; (a) CMK 21392, 27.8 mm; Laos: Mekong drainage: Xe Kong watershed; (b)–(d) CMK 7927, Vietnam: Dong Nai drainage, 36.2 mm, (b) reversed) 40.8 mm, 54.4 mm, (d) reversed; and (e) NRM 15095, holotype, 40.1 mm; Vietnam Dong Nai drainage (reversed). Kottelat (2023).

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Sunday 28 May 2023

Magnitude 6.5 Earthquake off the northern coast of Panama and Colombia.

The United States Geological Survey recorded a Magnitude 6.5 Earthquake at a depth of 13.0 km, off the Caribbean coasts of Panama and Colombia, about 50 km to the northeast of the border between the two countries, slightly after 10.05 pm local time on Wednesday 24 May 2023 (slightly after 3.05 am on Thursday 25 May, GMT). There are no reports of any damage or casualties associated with this event, though it was felt across much of northern Colombia, Panama and parts of Costa Rica.

The approximate location of the 24 May 2023 Pananma/Colombia Earthquake. USGS.

The event happened close to the triple junction between the Panama, Caribbean, and South American plates. All three plates are drifting to the northwest, being pushed by the expansion of the Atlantic Ocean, and to a lesser extent the eastward movement of the Nazca Plate, which is being subducted beneath the South American Plate along the west coast of South America. However, the South American Plate is moving somewhat faster than the other two plates, causing the Panama Plate to be pushed to the west, creating a transform plate margin, as the Panama Plate moves west relative to the Caribbean Plate, along the northern coast of Panama, and a subductive plate margin, as the Caribbean Plate is forced under the advancing South American Plate, along the northern coast of Colombia. 

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

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Saturday 27 May 2023

Plans for Early Neolithic megastructures discovered in the northern Arabian desert.

Humans have been making physical representations of the world around them for at least 40 000 years, principally by creating images and carvings of important things within that world. Maps and plans provide two-dimensional representations of three-dimensional spaces on a reduced scale, to help their users understand and navigate those spaces, and are considered to be a special type of physical representation, resulting from a significant cognitive jump in our understanding of the world. Humans have been modifying their world in a way that implies a degree of advance planning for many thousands of years, but the earliest known plans and maps currently date from the early literate societies of Mesopotamia and Egypt, and even from this era such maps and plans are very rare. How earlier Neolithic communities planned buildings and other communal spaces is unclear. 

In a paper published in the journal PLoS One on 17 May 2023, Rémy Crassard of the Laboratoire Archéorient at Université Lyon 2Wael Abu-Azizeh, also of the Laboratoire Archéorient at Université Lyon 2, and of the Institut Français du Proche-OrientOlivier Barge, again of the Laboratoire Archéorientt at Université Lyon, Jacques Élie Brochier of the Maison méditerranéenne des sciences de l'homme at Aix Marseille UniversitéFrank Preusser of the Institute of Earth and Environmental Sciences at the University of FreiburgHamida Seba and Abd Errahmane Kiouche of the Laboratoire d'InfoRmatique en Image et Systèmes d'information at the Université de Lyon, Emmanuelle Régagnon and JuanAntonio Sánchez Priego, again of the Laboratoire Archéorient at Université Lyon 2, Thamer Almalki of the Heritage Commission at the Ministry of Culture of Saudi Arabia, and Mohammad Tarawneh of the Petra College for Tourism andArchaeology at Al-Hussein Bin Talal University, describe the discovery of realistic plans for desert kites, Neolithic megastructures believed to have been used as traps for wild Animals, from southeast Jordan and northern Saudi Arabia.

Other representations of kite structures have been found before, but these are somewhat rough in execution, and appear to be generic images, rather than depicting specific kites, whereas the images reported by Crassard et al. appear to be extremely detailed and accurate depictions of specific kites close to the site of the representations. These plans are presumed to have been made by the same people who made and used the kites, as the kites themselves are to large to be directly observed from the ground, and are generally understood by modern observers only once seen from the air. This reveals the degree of planning that went into these structures, and the grasp of the landscape possessed by the people who made it. The plans may have been used in developing hunting strategies involving the traps, as well as in the construction of the traps themselves, and reveal the way in which their makers were able to perceive space and plan communal activities in advance.

Desert kite are megalithic structures comprising two or walls forming a driving line which can range in size from hundreds of metres to several kilometres across, leading to an enclosure with a typical area of about 10 000 m², surrounded by up to 20 pit traps, which can be as much as 4 m deep, into which Animals were driven by the hunters. These are the earliest Human-built large scale structures known, with the oldest examples dating to about 9000 years ago in the pre-pottery Neolithic of Jordan. 

Distribution and characterization of desert kites. (A) Desert kite plan from Kazakhstan (Ustyurt Plateau). (B) Desert kite plan from Armenia (Mount Aragats). (C) Desert kite plan from Jordan (Harrat al-Shaam). (D) Desert kite plan from Saudi Arabia (Khaybar). (E) Distribution area of desert kites from western Arabia to Uzbekistan. (F) Oblique aerial picture of a desert kite in Jordan (Harrat al-Shaam, photo OB, Globalkites Project). (G) Oblique aerial picture of a desert kite in Saudi Arabia (Khaybar). (H), (I), (J) Desert kite pit-traps during and after excavation (of half the pit) in the Harrat al-Shaam region of Jordan. Crassard et al. (2023).

Hunting techniques of ancient Humans (and Hominins) have been studied by archaeologists for a long time, but most of this effort has been directed at weapons technology, with structures such as desert kites only receiving attention in the past few years. The first known desert kites were observed during aerial surveys in the 1920s, but the advent of satellite photography has revealed how widespread these structures are, with examples known from Arabia through the Middle East and Caucasus Mountains and Uzbekistan and into Central Asia, and west across the Sahara as far as Mali and Mauritania. These are believed to have been used in large-scale hunting enterprises targeting whole herds, carried out in desert areas far from permanent settlements. Their appearance, along with the appearance of the first farms in the Near East, indicates the emergence of a highly innovative approach to obtaining resources, in this case meat and other Animal resources, which goes far beyond meeting simple subsistence needs. This marks the beginning of a process by which Humans came to take control of landscapes across the planet.

Kite JKSH 04 (JD1091). Top plan and different views of the excavation of pit trap St.02. Crassard et al. (2023).

The Globalkites Project website now records over 6000 desert kites, across the Sahara, Middle East, Caucasia, and Central Asia. These are most numerous on the lava fields of s Harrat alShaam in southern Syria, eastern Jordan and northern Saudi Arabia, where in places they reach one kite per square kilometre. Investigation of this area led to the discovery of two rock engravings, which appear to show nearby desert kites depicted to scale. These are on the Jibal al-Khashabiyeh plateau at the eastern edge of the Al-Jafr Basin in south-eastern Jordan and the Jebel az-Zilliyat plateau at the northern edge of the Nefud Desert in northern Saudi Arabia, with the two sites being 267 km apart.

Map showing the distribution of known desert kites. Globalkites Project.

Jibal al-Khashabiyeh is a limestone plateau about 80 km to the east of the city of Al-Jafr, which reaches a maximum elevation of about 1 km above sealevel, and slopes to the east. The plateau is rich in chert, particularly on its upper elevations. There are eight kites known from this escarpment, built from slabs of white limestone and piles of chert. As well as the kites, eight ancient campsites have been found, apparently one per kite, of which three have been excavated by archaeologists, including one, F15, which had previously been targeted by looters, and which yielded the first stone engraving representing a kite.

Location of fieldwork in Jordan. Location of the eight desert kites in the Jibal al-Khashabiyeh region in south-eastern Jordan (left), and detailed plans of these kites (right), with mentions (St.n) of excavated pit-traps. The red dot in the general map (left) shows the location of the engraving, found at the JKSH F15 site. The green dots in the kite plans indicate the excavated pit-traps and their numbering. Crassard et al. (2023).

Jebel az-Zilliyat lies 260 km to the east in Al-Jawf Province, Saudi Arabia, where it forms part of a complex landscape of grabens and faults. Two kites are present on top of the plateau, AB135/AB136 and AB547/AB549, separated by about 3.5 km. During a foot survey of a drainage feature on the plateau, a large engraving apparently depicting both kite enclosures, drawn to scale, was discovered. 

Location of the fieldwork in Saudi Arabia. Location of the four desert kites in the Jebel Az-Zilliyat region in northern Saudi Arabia (top), and detailed plans (bottom) of the two pairs of kites. The red dot in the general map (top) shows the location of the engraving, in the bed of Wadi az-Zilliyat. The green dots in the kite plans indicate the excavated pit-traps and their numbering. Crassard et al. (2023).

The F15 site on Jibal al-Khashabiyeh is a pre-pottery Neolithic site which has been disturbed bu recent looting. Despite this, numerous carved stones are still present, albeit for the most part disturbed and not in their original positions. Many of these conform to the 'ciger-shaped stone' form associated with the pre-pottery Mureybetian Culture, which was found across the Near East from about 10 200 to about 8000 years ago. One notable such monolith, found in June 2015, and measuring roughly 80 cm long, 32 cm wide, and 18 cm deep, and weighing 92 kg, shows a well preserved engraving of a kite.

Discovery of the engraved stone in Jibal al-Khashabiyeh, Jordan. (A) Orthomosaic view of JKSH F15 site where the kite’s engraving was found on a monolith (in red is the location of the rescue excavation in the looter’s spoil). (B) Photograph of the engraved stone at the time of discovery at the JKSH F15 site (the monolith was found lying down and was set vertically for the photograph). (C) Photogrammetric 3D model of the engraved monolith showing the different faces, including the engraved upper face (top), while the hill-shaded model (bottom) shows the interpretative drawing of the engraved plan on the stone. (D) Drawing of a projected view of the kite representation engraved on the monolith from the JKSH F15 site. Crassard et al. (2023).

The edges of the monolith appear to have been shaped with a large hammerstone, while the engraved depiction of the kite shows a mixture of carving techniques. Fine incisions have been used to delineate the borders of the kite, while a pecking tool has been used to etch out the interior area. The limestone of the monolith is soft and chalky, and could have easily been worked with a burin, scraper, or similar chert tool. The surface of the plateau is covered with high-quality chert, much of which shows signs of having been modified by Human activity. The entire interior of the kite has been carved out to a depth of 0.5-1.0 cm, producing a smooth, low relief model.

Detailed photographs of the engraved stone surface from Jibal al-Khashabiyeh, Jordan. The detailed views emphasize the various techniques used for the kite engraving found at the JKSH F15 site. The detailed photographs on the left are lettered, indicating their position on the engraved monolith, as shown on the right. Crassard et al. (2023).

The carving can clearly be seen to be a kite structure, with the driving lines depicted by two converging carved lines about 40 cm in length, leading to a star-shaped central enclosure about 26 cm in diameter, with a circumference marked bu eight cup-shaped depressions at the tips of the star-points, ranging from 2.5 to 6 cm in diameter, which represent the pit traps of the kite. Part of the right side of the enclosure is missing, either having been lost to weathering or never completed, and, given the overall symmetry of the shape, it appears likely that a ninth cup-shaped depression would have been present in this section. The driving lines are almost parallel, forming a long, straight, corridor-shaped funnel, with a sharp 90° turn and sharp convergence at the entrance to the central enclosure. This plan is common in kites seen in southeastern Jordan, and more rarely in northern Saudi Arabia, but is not known from other kite-assemblages in the region. 

Just before the turn in the driving line, a series of five chevrons can be seen running across the width of the corridor, which Crassard et al. suggest may be of symbolic significance, or represents a structure made from lighter materials which have not been preserved, such as a beater-driven hunting spot or a net, or (most likely) represent a break in the topography. 

The Jebel az-Zilliyat representation is significantly larger, and was discovered during a survey of rock are in Wadi az-Zilliyat, which cuts across Jebel az-Zilliyat, in March 2015. Two representations of kites are engraved upon a flat surface on the side of a sandstone boulder, which had fallen to the floor of the wadi from an overhanging cliff. The eastern of this pair of posts is readable, but the one on the western side is heavily eroded. The plan here was constructed entirely by pecking at the rock with some sort of hand tool. As at Jibal al-Khashabiyeh, abundant chert is available at the site, from which a suitable tool could have been made. The eastern kite has two short, widely spaced, converging driving lines, measuring 80 cm and 85 cm, respectively. These lead to star-shaped enclosed area 50-60 m across, with a cup-shaped pit 3-5.5 cm deep at the tip of each of its six points. The southernmost two of these cups are around a corner on another face of the rock. The western kite is less clearly defined, with much of the image apparently lost to rock exfoliation, It has two converging driving lines, 85 cm and 60 cm in length, and a star-shaped enclosure 40-45 cm across with at least four cup-shaped depressions. The southern part of this enclosure is missing. It is unclear if the engraving was made on the rock before or after it split from the rock face.

Location of the engraved rock in Wadi az-Zilliyat, Saudi Arabia. (A) General view of Wadi az-Zilliyat, from the northeast, the location of the engraved boulder is shown by the white circle. (B) General view of the collapsed boulders from the southeast, the white circle indicates the position of the engraving. (C) General view of the engraved rock (white circle) location among the collapsed boulders, from the east. (D) The engraved boulder as discovered during rock art survey, view from the north. Crassard et al. (2023).

It was not possible to date the engravings at either site, although a radiocarbon date of 8016 years before the present (6930 BC) was obtained from a piece of charcoal at the F15 campsite on Jibal al-Khashabiyeh. This campsite had apparently been disturbed by looters, making the context slightly difficult to interpret, but the site appears never to have been re-used after its initial occupation, so it is likely that the date will be close to the creation of the engraving and nearby kites.

The engraved boulder from Jebel az-Zilliyat, Saudi Arabia. (A) Drawing of a projected view of the kites’ representation showing picking tool traces, engraved and weathered zones. (B) Drawing of a projected view of the kites’ representation showing legible and unclear engravings, with a colored restitution of the microtopography of the boulder surface. Crassard et al. (2023).

Crassard et al. next set out to compare the designs of the depicted kites to actual kites in the region. All of the eight kites on Jibal al-Khashabiyeh are similar to the design depicted in the engraving, with four having a sharp bend at the point where the converging driving lines meet the enclosure, including the two kites closest to the engraving, JKSH 07 and JKSH 08. In both of these kites the northern driving line remains straight while the southern line curves sharply, to create the bend in the corridor that leads to the enclosure, which is the layout depicted in the engraving. All of the kites on Jibal al-Khashabiyeh have been heavily eroded by water drainage since their creation, so that the star-shaped enclosures can only be identified in three structures; at JKSH 01 eight pit-traps are preserved, and it appears likely that there were originally nine (from the shape of the enclosure and regular spacing of the pits). Kite JKSH 04 also has eight pits preserved, but in this case it is calculated that there were originally another three. At JKSH 07 only three pits remain, but it is thought likely that there were once another six. All three of these kites were excavated, revealing that the pits were stone-faced hollows 143-176 cm deep. One of the pits at JKSH 01 was found to contain five pieces of charcoal, one of which yielded a radiocarbon date of approximately 7000 years.

Detailed photographs and hill-shaded surface models of the engraved stone surface from Jebel az-Zilliyat, Saudi Arabia. The detailed views emphasize the various techniques used for the kite engraving. The detailed photographs and hill-shaded surface models on the left are lettered, indicating their position on the engraved boulder, as shown on the right. A and B are showing examples from the eastern depiction of a kite, C and D from the western one. Hill-shaded surface models are used to better render the legibility of the engravings, otherwise less visible from the photographs made on site. Crassard et al. (2023).

The engraved rock at Jebel az-Zilliyat lies within a wadi, which runs between two pairs of desert kites, AB547 and AB549 to the west, and AB135 and AB136 to the east. This eastern pair are separated from one-another by 120 m, and have south-facing openings and funnel entrances which run parallel to one-another. AB135 has a large, star-shaped enclosure, typical of kites in this region, with three driving lines, the longest of which is 3379 m. The preservation of this kite is not good, with parts of the structure having been raided for stone to make later stone-aged structures, such as tombs (stone mounds, cairns) and circular structures (pastoral or dwelling enclosures), and more recently other parts having been demolished during gas and oil exploration work.

Comparison of the kite layouts depicted on the engravings with the top-view plans of neighboring desert kites in Jibal al-Khashabiyeh, Jordan and Jebel az-Zilliyat, Saudi Arabia. (A) Comparison of the kite layout depicted on the engraved monolith (left) with the top-view plans of the four better preserved kites identified in Jibal alKhashabiyeh (right). The red dotted line is the shape of the kite engraving, used for superimposition on the desert kite maps. (B) Comparison of the kite engraving found at Jebel az-Zilliyat (left) with top-view plans of the four neighboring desert kites (right). Gray zones are destroyed or reused areas, after the period of kite use. Crassard et al. (2023).

Despite these problems, a combination of aerial observation and fieldwork has allowed Crassard et al. to build up an accurate idea of the original structure of AB135. The kite has four well preserved pit traps on its northwestern side, and two more on its southern edge, at the edge of a plateau cliff. The eastern one of these is heavily damaged, making it difficult to assess its original structure. A series of further pit traps are present on the northern side, along the structure's driving lines, but these are of a different design, of courser construction, and show a different degree of desert varnish (an orange-yellow to black coating found on exposed rock surfaces in arid environments, composed of particles of clay along with oxides of iron and manganese), suggesting that these were built as add-ons to the original structure at a later date. 

Kite DAJ137 (AB135). (A) Aerial view of pit-traps L03 (archaeological excavation), L04 and L05. (B) L03 before excavation. (C) L03 after excavation. Crassard et al. (2023).

Two of the pits at AB135 were excavated; AB135-L01, which yielded some old red altered soil unsuitable for optically stimulated luminescence or radiocarbon dating, and AB135-L03, which produced five fragments of calcitic nutlets of Arnebia sp., from a layer about 10 cm above the bottom of the pit. These fragments yielded a radiocarbon date of approximately 6760 years before the present (about 5670 BC), while a sample of sediment from the bottom of the pit yielded an optically stimulated luminescence date of approximately 7690 years before the present (about 5675 BC); this theoretically should be a date after the trap fell into disuse and began to fill with sediment, providing a minimum age for the structure. 

Kite DAJ140 (AB549). Aerial oblique view of the enclosure. Crassard et al. (2023).

Kite AB136 is better preserved than its neighbour, consisting of two driving lines, 156 m and 54 m in length, plus a 4200 m² enclosure with six pits. None of these pits contained any significant amount of sediment, preventing any useful archaeological excavation of the site.

Kite DAJ140 (AB549). Aerial view of pit-traps L01 (archaeological excavation, on the left) and L02 (on the right). Crassard et al. (2023).

The pair of kites on the western side of the wadi, AB547 and AB549, appear to have been made using the same construction techniques as the kites on the west, but are much better preserved. These appear to have shared a single pair of driving lines, these being 1549 m and 2623 m in length, while the two traps have enclosures of 5500 m² and 6300 m², respectively, and both have six pit traps. None of the pits of AB547 was considered suitable for excavation, although careful examination of the structure in the field appeared to confirm that it was structurally related to AB549, with the two structures apparently being used together. One of the pits of Kite AB549 was excavated, having 60 cm of accumulated sediment above its base, Here eleven small fragments of Arnebia sp. nutlet were found, one of which yielded a radiocarbon date of 3300 years before the present, or about 1570 BC, while sediment from near the base of the pit produced two optically stimulated luminescence dates of approximately 8040 and 7480 years before the present (about 6025 and 5465 BC). Crassard et al. note that this difference in the dates obtained using the radiocarbon and optically stimulated luminescence dating methods underlines the need to use more than one dating method where possible. In this instance they believe that the anomalous date from the Arnebia sp. nutlets ewas due to the high mobility of such small plant remains, and that the sediment dates provide a minimum age for the trap falling into disuse.

Composite ortho-mosaic illustrating the fully deployed projection view of the engraved monolith found at JKSH F15 site. An outlined drawing shows the interpretation of the whole engraving. Crassard et al. (2023).

Crassard et al. tested the similarity of the kite engravings to kite structures in the region using a computer-based graph modelling based upon satellite images of the kites. Graphs are mathematical structures, with vertices (fixed points) linked by edges (lines), making them highly suitable for comparing similar structures, and are commonly used in studies of desert kites.

Hypothetical interpretation of the chevron pattern engraved on the kite depiction on the monolith from JKSH F15 site, Jordan as a topographic symbol. The detail of the chevron pattern (bottom) is compared to the slope break seen in the topography (here at kite JKSH 04, top). Crassard et al. (2023).

The model used by Crassard et al. compared the kite images to 69 actual kites in the region, concluding that the kites showed between 26.83% and 81.43% similarity to the Jebel az-Zilliyat engraving and between 11.46% and 75.90% to the Jibal al-Khashabiyeh engraving, where 100% would represent an exact match. This suggested that the kite most similar to the Jebel az-Zilliyat engraving is AB135, which is only 2.3 km from the engraving, while the most similar kite to the Jibal al-Khashabiyeh engraving is JKSH 01, which is 16.3 km from the engraving. However, JKSH 01 is only a 75.9% match for the Jibal al-Khashabiyeh engraving, note notably greater than the kite JKSH 07, which is 73.52% similar to the engraving, and only 1.4 km away.

Reconstruction of the layout of the enclosures at the three excavated kites in Jibal al-Khashabiyeh, Jordan. The reconstruction is based on the structural remains preserved in the field to estimate missing pit-traps around the enclosure’s perimeter. Crassard et al. (2023).

The kite engravings show clear similarities to the actual kite structures, something which can be detected when both qualitative and quantitative approaches are used, and appear most likely to be direct representations of the kite structures closest to them. These carvings are realistic, and surprisingly accurate to scale, given the gigantic size of the kite structures and the difficulty in comprehending their layout without access to modern imaging methods. The engravings appear to be accurate depictions of these large structures intended to help their builders/users develop a mental map of the site.

The Jebel az-Zilliyat eastern engraving shows a very clear similarity to the adjacent AB135 kite, which includes the location of two southern pits on the edge of the escarpment, which in the engraving are represented by two cups on a separate planar surface, giving a three dimensional aspect to the representation. This Jebel az-Zilliyat engraving depicts a pair of kites rather than a single structure, and AB135 is part of a pair of kites, one of two pairs of kites which are close to this engraving. The engravings are reasonably accurate at a scale of 1:175, with compass directions on the immobile boulder matching those of the actual kites. 

The Jibal al-Khashabiyeh engraving also shows strong similarities to nearby kites, with the engraving having a similar shape and number of pit traps to these kites, clearly visible when the images are super-imposed, and supported by computer modeled graph plotting of the structures. Notably, the proportions of the corridor leading to the enclosure on the engraving are a very close match for kites JHSH 01 and JKSH 04. This model has a scale of 1:425, with the size of the pits considerably exaggerated in the model compared to the actual kites, which is a reasonable approach, given that they would have been barely perceptible at true scale. Seen in this way. the larger pits still act as useful representations of the place to which Animals should be herded.

This is the first known example of an accurate depiction of a Neolithic structure made by the people who constructed it, and therefore the oldest example of such a plan in Human history. Some older images, from the Upper Palaeolithic of Europe, have been interpreted as schematic maps of the local environment; but these cannot be said to depict a scaled model of the landscape.The oldest European maps are Bronze and Iron Age representations of agricultural land divisions, showing s field features, enclosures, and dwelling areas, as well as road networks, although it is unclear if these relate to the areas where they were found. some more distant environment, or even imaginary landscapes.

The beginning of the Neolithic coincides with the onset of the Holocene in the Near East, and is accompanied by the the building of large, often megalithic, structures, and a subsequent change in social structures which included the domestication of Animals, the appearance of settled communities, the emergence of farming, the development of social hierarchies, and the beginnings of long-distance trade. Despite this, depictions of the spaces in which all these activities took place are rare. A mural from the city of Çatalhőyűk in Anatolia, dated to about 6600 BC, may be a form of map, showing a village and a volcano, possibly a reference of an eruption on Mount Hasan Dağ. A scale model of a reed boat, from Kuwait has been dated to about 5000 BC, while model houses are also known from the Kodjadermen-Gumelniţa-Karanovo culture of the eastern Balkans, dating from about 4500 BC. However, none of these can be considered to be true plans in the way that the kite depictions appear to be. The oldest representations considered to be true plans until now have been from second and third century sites in Mesopotamia, though even these are maps of large areas which do not approach the degree of accuracy seen in the kite engravings. 

Prior depictions of the kite structures have been uncovered in Jordan, Syria, and Uzbekistan, although these are not to scale, and have not been dated accurately. While these are not plans in the sense that the new material are, typically being simple, figurative images, these do reveal information about the way in which the kites were used, for example by depicting Animals and Hunters within the kites. These images typically have much reduced driving lines, but greatly exaggerated pits, apparently to emphasize their important function. Furthermore, none of these previously observed figurative kite could be associated with a particular actual kite.

Examples of previously known kite engravings, that are not represented to scale and less realistic. (A) From cairn of Hani’ site, Syria; (B) From Khishâm-2 site, rock В 37, Syria; (C) From Wisad Pools, Jordan; (D) From Azraq Basin, Jordan; (E) From Wisad Pools, Jordan; (F) and (G) are the kite engravings described in Crassard et al.'s study, respectively from Jibal al-Khashabiyeh and Jebel az-Zilliyat, represented in this figure to be directly compared with the previously known ones. Crassard et al. (2023).

Desert kites are large structures, and building them would have required a good understanding of the topography of the region, and the ability to take into account features such as convex surfaces and breaks in slopes. Thus a plan of the a kite structure could have been used to aid the design of such a structure, as a tool for organizing hunts involving the use of a kite, for some symbolic purpose not obvious to modern observers, or any combination of these.

If the kite engravings do represent construction plans, then they would have formed part of a process that began with studying the topography of the area, and the migration patterns of Animals passing through, before formalizing the plan. It would have also required the kite-builders to have the skills to follow such a design during the construction phase. The engraved kites examined by Crassard et al. show a very accurate scale plan of the kites, but do not show all of the topological features which it would have been necessary to take into account during construction, for which reason, Crassard et al. do not believe that they served as blueprints for the construction of the kites. 

The possibility that the plans were used during the organization of hunts seems to be a much more plausible explanation. Such a model, if sufficiently accurate, could be used to plan where hunters would be placed at the outset of a hunt, and to co-ordinate subsequent movements by the hunters, even taking into account what to do in the event of Animals reacting to the hunters in different ways. Seen in this light, the plan is a visual communication device pre-dating the invention of writing, acting as an aid to communication, but probably not useful without some other interaction. Nevertheless, such a plan would be likely to facilitate the development of hunting strategies, and probably led to far smoother hunt operations than would have been possible without it. The plan involves an understanding of the design of the kite and the topography upon which it sits which was probably only available to the builders of the kite, and takes into account features hidden  by that topography, such as the pits on the cliff edge at Jebel az-Zilliyat. The chevrons on the Jibal al-Khashabiyeh  kite engraving appear to be a symbolic representation of a spatial feature, and while it is difficult to determine what that feature was, this is apparently a very early example of a cartographic practice still in use today.

The plans are not completely to scale, with the most important features, i.e. the pit traps, exaggerated in size, apparently with the intention of increasing the utility of the diagram. Thus the plans represent a compromise reached while trying to find a method of controlling information, in order to make it more possible to pass on to others. In a sense, therefore, these representations can be seen as symbolic as well as practical, with the communicative function being more important than the need for complete accuracy, despite the importance clearly placed upon making an accurate representation.

Despite this use of symbolism, Crassard et al. believe that the primary function of the engravings was utilitarian rather than symbolic purpose, either aiding in the construction or (more likely) use of the kite structures.

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