Magnitude 6.2 Earthquake in Escuintla Department, Guatemala, kills two.

The United States Geological Survey Recorded a Magnitude 6.2 Earthquake at a depth of 83.6 km beneath the town of Nueva Concepción, in Escuintla Department, Guatemala, slightly after 1.10 am local time (slightly after 7.10 am GMT) on Wednesday 16 February 2022. Two people are reported to have died due to this event, both due to heart attacks, a number of buildings have been damaged, and several landslides triggered. People have reported feeling this event across Guatemala and El Salvador, as well as in parts of Honduras and Mexico.

 

 

The approximate location of the 16 January 2022 Guatemala Earthquake. USGS.

Guatemala is located on the southern part of the boundary between the North American and Caribbean Plates, close to their boundary with the Cocos Plate, which underlies part of the east Pacific. The Cocos Plate is being pushed northwards by expansion of the crust along the East Pacific Rise, and is subducted beneath the North American and Caribbean Plates along the Middle American Trench, which runs parallel to the south coast of Guatemala and neighbouring countries, passing under Central America as it sinks into the Earth's interior. This is not a smooth process, the plates tend to stick together, breaking apart again once the pressure from the northward movement of the Cocos Plate builds up to much, triggering Earthquakes.

 

Diagrammatic representation of the subduction of the Cocos Plate beneath the Caribbean Plate along the Middle American Trench. VCS Mining.

 

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Odontochrydium arabicum: A new species of Cuckoo Wasp from the Arabian Peninsula.

Cuckoo Wasps, Chrysididae, are a widespread and diverse group of Wasps, noted for their kleptoparasitic habits; that is to say that, like many Wasps they lay their eggs inside the paralized bodies of other Insects and Arachnids stored in nests, but unlike these Wasps they do not catch their own prey, but rather lay their eggs inside the victims of other parasitic Wasps, the Cuckoo Wasp larvae then eating both the prey and the larvae of the original Wasp. The genus Odontochrydium currently contains three species of Cuckoo Wasps, two from sub-Saharan Africa and one from southern India.

In a paper published in the journal Zootaxa on 18 February 2022, Ahmed Soliman of the Plant Protection Department at King Saud University and the Zoology Department at Al-Azhar University, Paolo Rosa of the Laboratoire de Zoologie at the Université de Mons, and Hathal Dhafer, also of the Plant Protection Department at King Saud University, describe a new species of Odontochrydium from the southern Arabian Peninsula.

The first reported example of a Wasp of the genus Odontochrydium was a female collected from the Asir region of Saudi Arabia in 2015, and identified as a member of the species Odontochrydium bicristatum, which is otherwise known only from East Africa. However, since this report other specimens collected in southern Saudi Arabia, Oman, and Yemen have come to light, including several males (which show greater differentiation between species than is seen in the females), leading Soliman et al. to conclude that the Arabian population is in fact a different species to the East African population.

The new species is named Odontochrydium arabicum, where the specific name 'arabicum' refers to the Arabian Peninsula. The species is described from ten specimens, four males and six females, collected from the Asir and Jazan regions of Saudi Arabia, the Dhofar Governate of Oman, and Yemen.

 

Odontochrydium arabicum, male, holotype. (A) Habitus, lateral view; (B) Habitus, dorsal view; (C) Habitus, ventral view. Scale bar is 1.0 mm. Soliman et al. (2022).

Males and females of Odontochrydium arabicum are bright green with copper shimmering when alive, but turn a dark metallic blue after death. Both sexes have covering of fine white hairs, and tiny pits. The eyes are also white. Adult Wasps reach about 5.2 mm in length.

 

Odontochrydium arabicum, female, paratype. (A) Habitus, lateral view; (B) Head, frontal view; (C) Mesosoma and T1, detail; (D) T2–T3. Scales is 1.0 mm. Soliman et al. (2022).

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Secondary cratering from the Early Permian of Wyoming.

Many Solar System bodies, including our Moon, are covered by enormous numbers of impact craters. On Earth, in contrast, the total number of such craters discovered stands at 208. This is largely due to the Earth's active surface, with the continents and continental shelves being subjected to constant erosion and deposition of sediments, and the ocean floors being constantly recycled through subduction and seafloor spreading. However, the situation is more complicated than it seems at first sight; many of the craters seen on the Moon and other Solar System bodies are in fact secondary craters, formed by debris ejected from larger impact events. Once understood, such craters have been relatively easy to identify, frequently being elliptical rather than circular in shape, shallower than primary craters, and arranged radially around the initial impact crater. The implications of this are debatable, with some planetary scientists arguing that as many as 95% of small craters on some bodies may be secondary in origin, whereas others see them as a insignificant proportion of the total number.

In a paper published in the journal GSA Bulletin on 11 February 2022, Thomas Kenkmann and Louis Müller of the Institute of Earth and Environmental Sciences at Albert-Ludwigs-Universität Freiburg, Independent Consultants Allan Fraser and Doug Cook, Kent Sundell of the School of Science at Casper College, and Auriol Rae, also of the Institute of Earth and Environmental Sciences at Albert-Ludwigs-Universität Freiburg, describe the discovery of a secondary impact field comprising at least 31 craters, and possibly as many as 60 more, in southeastern Wyoming, USA. 

The presence of a field of impact craters in the Rocky Mountains in Wyoming was first reported in 2018 by Thomas Kenkman, Kent Sundall, and Douglas Cook. At the time they reported about 40 circular-to-elliptical structures on a tilted Permian exposure on the northeast flank of the Sheep Mountain, eight of which showed sufficient grain deformation to be confirmed as impact structures. These were initially interpreted as the result of a single large object which broke up as it entered the atmosphere, resulting in a group of closely clustered craters.

The new paper by Kenkman et al. describes the presence of several other craters on Sheep Mountain Ridge, and other exposures of the same age at Wagonhound Ridge, Mule Creek, Fetterman Ridge, Fetterman Road, and Palmer Canyon Road, as well as possible craters at several other locations. These range from 10 to 80 m in diameter, and while many are circular, some are as much as 1.7 times as long as they are wide. All of the structures which are firmly established as being craters lie at the top of the Casper Formation, which is immediately overlain by the Opeche Shale member of the Permian Goose Egg Formation, dating the impacts to about 280 million years ago, making them late Early Permian in origin.

 

Digital elevation model map of southeastern Wyoming, USA, and adjacent areas showing the exposure of Casper Formation and the locations of the secondary craters. Based on the intersection of trajectory fans, the proposed site of the possible primary crater is reconstructed. SM, Sheep Mountain; MC, Mule Creek; FR, Fetterman Ridge; FRX, Fetterman Road; PCR, Palmer Canyon Road; WR, Wagonhound Ridge; BE, Box Elder Canyon; MR, Manning Ridge. Kenkman et al. (2022).

The Casper Formation is made up primarily of aeolian sandstones (i.e. sands laid down in a terrestrial desert or dune environment), although the uppermost portion of the section, where the craters are preserved, represents a marine transgression into this environment, forming a lagoon or sabkha environment (a sabkha being a coastal saltpan regularly refilled by tidal waters and emptied by evaporation). The craters sometimes form pedestals standing above the eroded surface of this formation, resulting from lithification processes of associated with the impacts, such as shock fusion (welding together of particles by a sudden impact), and cementing by a glassy melt formed within the crater.

 

Remote sensing images of selected craters of the different crater fields. (A), (B), (D), and (E) are drone images; (C), (F), and (G) are Google Earth imagery. Crater locations: SM, Sheep Mountain; MC, Mule Creek; FR, Fetterman Ridge; FRX, Fetterman Road; PCR, Palmer Canyon Road. (A) Crater SM-1 has an elliptical outline, a pedestal morphology with a preserved proximal ejecta blanket, and a raised rim. The downrange (northwest) rim shows an overturned ejecta flap. The linear ejecta wall is interpreted as a herringbone pattern. (B) Craters SM-6-3-4-5 form a northwest-southeast–trending radial crater chain. The ovoid crater SM-2 shows an overturned ejecta flap downrange (northwest) and a linear ejecta wall. (C) Craters MC-1 and MC-2 represent eroded craters with very little topography but a concentric fracture pattern. (D) Strongly degraded craters FR-1 and FR-2 contain shock effects along their crater rims. (E) The deeply eroded crater SM-9 is circular and has a bright halo of quartzitic sandstone. (F) Crater FRX-20 is a strongly elliptical landform with a gently rising rim. (G) The western and northern rim of crater PCR-1 exposes steeply dipping rocks. PCR-2 shows an elliptical outline. Kenkman et al. (2022).

The Casper Formation, on the upper surface of which the craters are preserved, has very little surface exposure, 1% of in Converse County and only 4% in Albany County, suggesting that many more craters may be preserved buried beneath the centre. This area lies within the Laramide Mountains, an area within the wider Rocky Mountains where Late Cretaceous to early Eocene (~75-50 million years ago) reverse faulting and folding uplifted an area of Archean basement rocks and the material overlying it. Most of the known craters lie upon the Sheep Mountain flank of the Sheep Mountain anticline, an extended fold-ridge mountain running from northwest-to-southeast, where the Opeche Shale has eroded back revealing the upper surface of the Casper Formation; it has been calculated that about 2 km of overlying rocks have been eroded away here since the onset of the orogeny; strata that are still likely to be in place in other areas, covering up other craters associated with this field.

 

(a) Simplified geological map of the Wyoming state. (b) Aerial photograph of Sheep Mountain anticline (view from the NNW); (c) Geological cross-section through of Sheep Mountain anticline perpendicular to the strike of the average fold axis, and (d) Geological map of the Sheep Mountain anticline area. Amrouch et al. (2010).

Wagonhound Ridge is a similar, and associated, structure to the south of Sheep Mountain, showing slightly less uplift. The Mule Creek, Fetterman Ridge, Fetterman Road, and Palmer Canyon Road exposures are found on the southwestern slope of the basement uplift of the Laramie Mountains in transition to the Shirley Basin, where the Casper Formation has largely been eroded away, but is exposed on several remaining buttes.

The largest cluster of impact-related structures is found on the northeastern flank of the Sheep Mountain, where a series of circular, irregular-shaped, and ellipsoidal have been confirmed as impact craters. These vary in their preservation quality from pristine to heavily eroded, with erosion apparently linked to the recent exposure of structures which were rapidly buried after their formation; i.e. the most eroded structures are located higher on the flanks of the mountain. The most pristine structures show steep crater walls, raised rims with overturned ejecta flaps, and remains of proximal ejecta blankets. These craters have floors are covered by soil and filled with muds derived from the overlying Opeche shales, making it hard to establish their depth-to-diameter ratio. Many of these craters are elliptical-to-ovoid in shape, with their long axes having fairly consistent orientations of 315–328°. The distribution of ejecta around the craters is uneven, with well-developed overturned flaps on their northwestern sides, suggesting they were caused by debris thrown from a primary impact to the southeast. Four of the craters form a chain, with a similar orientation. The more eroded structures further upslope tend also to be more rounded, with an internal ring structures. These often stand proud of the eroded surface, being more resilient to erosion due to the shock-fusion of the sandstone.

Ten possible craters have been found on the exposed surface of the Casper Formation at Wagonhound Ridge. Two of these have been confirmed as definite craters due to elevated rims. These are again filled with soil, and slightly elliptical. 

At Mule Creek a large elliptical crater measuring 56 m by 44 m has an orientation of 284±5°. A second structure, measuring 30 by 27 m is adjacent to this. Neither of these are elevated above the surrounding rock surface, and neither preserves any rim structure or surrounding breccia. It is thought that these represent the lower portions of larger craters that have been mostly eroded away; the larger of them appears to be surrounded by a larger ring at a distance of about 100 m, possibly representing underlying rocks that were consolidated by the impact. This area is cut through by a north-south and northwest-southeast–trending tectonic joint system visible in remote sensing images, which would have served to hasten erosion in this area. This joint system extends about 300 m to the northwest of the main crater, and contains at least nine irregular, soil-filled depressions which might represent further impacts. Another cluster of possible craters, one of which has been confirmed as an impact structure, is found about 2.5 km to the southeast of the main crater at Mule Creek. These structures have crater rims composed of sandstone breccia sealed with chert matrix.

At Fetterman Ridge a series of erosional buttes have exposures of the upper surface of the Casper Formation which have been eroded away from much of the surrounding landscape. One of these, a hill measuring roughly 200 m by 100 m, hosts three impact craters, measuring 30 m by 22 m, 28 m by 17 m, and 10 m by 10 m. The long axes of the two elliptical craters trend west-north-west to east-south-east, although their southern rims are more eroded. The 28 m by 17 m is distinctly elevated on its northwestern rim, with a visible ejecta flap on its western side. Again, the brecciated and fragmented rocks are sealed by microcrystalline silica, making them resistant to erosion. Other buttes to the northwest and southeast show possible additional impact craters, although these are more heavily eroded.

The Fetterman Road cluster comprises six possible craters 7–30 m in diameter, some of which are distinctly eliptical. The most distinct of these is 25 m by 15 m and has an orientation of 296°. The rim of this crater is elevated about a metre above its interior.

Eight possible craters are present at Palmer Canyon Road, about 10 km to the southeast of the Fetterman Road cluster. The two most conspicuous of these measure 42 m by 40 m, and 28 m by 19 m. Again, elevated rims are composed of quartzitic breccia with microcrystalline chert fill.

 

Outcrop-scale observations at the Wyoming crater field. (A) Panoramic view of crater WR-5 that shows very little relief. Note the outcrops along the rim. Persons for scale. (B) Brecciated ejecta. Fragments are partly angular and partly subrounded (SM-34). (C) The wind-scoured crater walls composed of quartzitic sandstone show abundant ventifacts (PCR-001). (D) Chert with flow textures and vesicles is very abundant at most of the craters (SM-36). (E) Breccia with quartzitic matrix (PCR-001). (F) The variegated contact of Casper sandstone and the Opeche Member of the Goose Egg Formation contains a few shocked quartz grains. Kenkman et al. (2022).

All of the discovered craters are on the upper surface of the Casper Formation, and all are in sandstones, but the nature of these sandstones varies slightly from site-to-site, reflecting an environment which was fully sub-aerial in the southwest, passing through a braided-river system into a shallow marine environment with some carbonate deposition in the northeast. The presence of water in the sands in some environments does not appear to have led to degradation of the crater rims. In all cases the craters were buried beneath Opeche Shale Member red beds of the Goose Egg Formation rapidly after their formation.

Brittle deformation, indicative of sudden physical shocks, can be seen on both large and small scales. The crater rims and ejecta all show brecciation (breaking into angular fragments) and brittle deformation, while individual grains are often intensely fractured.

Microstructures related to impact. (A) Crosscutting {1013} and (0001) PDF lamellae in sample from crater SM-19 are decorated by fluid inclusions. (B) {1013} PDF lamellae in sample from crater MC-1. A + B show that shock effects are restricted to the detrital grains while the overgrowth is undeformed. (C) Relatively wide-spaced planar fracture lamellae in sample from crater WR-4. (D) Concussion fractures in adjacent quartz grains emanate from initial grain contacts. (E) Crater SM-28 contains abundant chert layers and chert lumps that are embedded in the sandstone. Some of the chert lumps contain spherical lapilli. For interpretation, see text. (F) Close-up of a spherical lapillus that is interpreted as an accretionary lapillus. The concentric rings are composed of microcrystalline quartz around a dark-colored center. All photomicrographs were taken with crossed polarizers. Kenkman et al. (2022).

However, shocked grains are somewhat rare in the crater sediments, with slides made up from samples taken in the field typically showing only two-or-three shocked grains, and these usually being surrounded by unshocked grains rather than clustered together. Shocked grains were found in all parts of the crater structures, and at a much lower fequency level, outside the craters in undeformed sands, probably indicating their having been blown from craters by winds shortly after their formation. The degree of fracturing implies that these grains were subjected to pressures in excess of 10 gigapascals. 

Cherty (amorphous) silica is present at all sites, often forming the matrix which binds the sand grains together. Investigation of one of the craters at Sheep Mountain found a variety of structures within this chert, including elongated shapes and wavy layers. Within the chert were spherical structures resembling accretionary lapilli; glassy grains which are typically associated with violent volcanic eruptions, formed by the accretion of glassy siliica layers onto grains suspended in hot, turbulent air. 

The Wyoming Crater Field shows a number of features that help the reconstruction of the direction being travelled by impactors. The most obvious of these are oval or elliptical shaped craters, and craters arranged into chains, which gives the orientation of the direction of travel, but not the actual direction. However, direction of travel can be determined by using the following lines of evidence: (1) a steeper crater wall uprange; (2) a preserved overturned ejecta flap downrange, with a preferred deposition of ejecta downrange; (3) an ovoid crater shape with the strongest curvature downrange, and (4) V-shaped herringbone patterns of ejecta pointing up-range. 

The area has been subjected to some deformation since the impact craters formed, but none appears to have had its orientation changed by more than about 5%, enabling the use of craters from different sites to attempt to relocate the site of the original impact. Based upon this, Kenkman et al. suggest that the original impact happened at a site with map co-ordinates close to 41°28′N, 103°59′W; all of the craters lie between 150 km and 200 km from this site.

Modelling of possible trajectories of objects thrown from a primary impact crater suggest that boulders with a diameter of 2 m would need an initial velocity of 3-4 km per second to reach 150-200 km from the initial impact, while 4 m objects could reach this distance with an initial speed of 2 km per second would also fall within this zone. Such objects would deliver energy in the range of 12 to 400 gigajoules when they impacted, arriving at angles of between 45° and 60°.

Kenkman et al. calculate that an object with a density of 2500 kg per cubic meter (typical for many rock types), with a 4 m radius impacting at 1 km per second would create an impact crater about 45 m in diameter. A similar object 2 m in radius would create a crater 25-30 m in diameter, depending on its angle of approach. A range of objects between 1 and 4 m in diameter, travelling at between 500 and 1500 m per second, would generate craters between 8 and 55 m in diameter, with larger impacts releasing more energy and creating more shocked material as a proportion of the impactors mass.

Kenkman et al.'s findings reveal a series of clusters of craters across a wide area of southeast Wyoming, all of which appear to have formed simultaneously about 280 million years ago. These are best explained as secondary craters caused by material thrown from a large primary impact crater. No obviously foreign material was found in any of the craters, making it likely that the impacting material was similar in composition to the rocks of the areas impacted, and reconstructions of the direction of travel suggest the primary impact was between 150 and 200 km from the discovered craters.

Based upon the reconstructed size and impact speeds of the ejecta material, Kenkman et al. predict that the original impactor would have been 2.0-2.7 km in diameter, and to have hit the ground at about 20 km per second, creating a crater 50-65 km in diameter. 

This would place the location of the original impact in Goshen or Laramie counties in Wyoming, or Kimball, Banner, or Cheyenne counties in Nebraska. These areas fall within the Denver Basin, and Permian strata are deeply buried beneath subsequent Mesozoic and Cainozoic deposits. Despite this apparent lack of accessibility, these deposits have been heavily boreholed by hydrocarbons exploration companies, which may enable reconstruction of the original impact site. To date, Kenkman et al. have not found evidence of distorted or missing sedimentary strata which might be associated with such an impact in any well log data examined, but one drill core, 1–35 Hawk Fee, does show a breccia layer at 3023–3066 m below the surface, and Kenkman et al. are hoping to visually inspect this core in the near future. 

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Mambawakale ruhuhu: A new species of Pseudosuchian Archosaur from the Middle Triassic Manda Beds of Tanzania.

The Archosaurs, the group which includes modern Birds and Crocodiles, as well as the extinct non-Avian Dinosaurs and Pterosaurs, appeared in the Early Triassic and underwent a major evolutionary radiation in the Middle Triassic, becoming the dominant group of terrestrial Vertebrates. One of the most important sources of Middle Triassic Archosaur fossils is the Manda Beds of the Ruhuhu Basin, in southwest Tanzania, which is thought to be Anisian in age (247.2-242 million years old), and therefore documents the early stages of the Archosaur radiation.

The first recorded collections of material from the Manda Beds were made in the 1930s by Gordon Murray Stockley of the Tanganyika Geological Survey and Francis Rex Parrington of the University of Cambridge, followed later in the same decade by the Austrian geologist Ernst Nowack, who were all involved in surveying the Ruhuhu Basin for mineral resources, with the fossils they collected being sent to museums in South Africa, the UK, and Germany. Most of the material collected by Parrington was brought back to the UK, where it was described by Alan Charig as part of his PhD dissertation in the 1950s, but this dissertation was not published, and no descriptions of this material was published until after Charig's death in 1997. 

Tanganyika gained independence from Britain in 1961, and in 1964 merged with another former colony, Zanzibar, to form the modern Republic of Tanzania. In 1963 Charig took place in another expedition to the region, organised by the British Museum (Natural History) (now the Natural History Museum) and including researchers from South Africa, Uganda, and the UK, as well as large numbers of unnamed Tanzanian and Zambian workers, who identified many of the sites from which fossils were extracted, as well as excavating the fossils, and building the roads upon which they were transported away, with the fossils once again being brought back to the UK and deposited in the collection of the Natural History Museum.

This expedition collected a number of important specimens, including the material from which the Pseudosuchian Archosaur Hypselorhachis mirabilis was described, and another specimen which Charig referred to as Pallisteria angustimentum in a number of publications, but appears never to have described; he referred to the specimen being described as being ‘in press’ at the journal Palaeontology, but no record of this paper appears to exist, suggesting it was never submitted, making the name invalid under the terms of the International Code of Zoological Nomenclature.

In a paper published in the journal Royal Society Open Science on 9 February 2022, Richard Butler of the School of Geography, Earth and Environmental Sciences at the University of Birmingham, Vincent Fernandez of the Imaging and Analysis Centre at the Natural History Museum, Sterling Nesbitt of the  Department of Geosciences at Virginia Tech, João Vasco Leite of the Department of Earth Sciences at the Natural History Museum, and David Gower of the Department of Life Sciences at the Natural History Museum, formally describe the material identified as Pallisteria angustimentum by Alan Charig under the name Mambawakale ruhuhu.

Renaming a specimen to which a name has previously been applied is an unusual step even where the name is not now considered valid; it would have been possible for Butler et al. to simply describe the specimen under Charig's nominated name, thereby legitimising it, but they chose to rename it in Kiswahili, in honour of the unnamed Tanzanian workers, who located, extracted, and transported the specimen, and who would have spoken Kiswahili. Charig's original name, Pallisteria angustimentum, comprised a genus name, Pallisteria, intended to honour John Weaver Pallister, who was Commissioner of Mineral Resources of Tanganyika at the time of the 1963 expedition, and provided some support for it, although he was in no way directly involved in the collection of the specimen, and a specific name, angustimentum, which means 'narrow chin' in Latin. The new name proposed by Butler et al. comprises the genus name Mambawakale, meaning 'ancient Crocodile' in Kiswahili, and the specific name ruhuhu, in reference to the Ruhuhu Basin, where the specimen was collected. As none of the team working on the project came from Tanzania or spoke Kiswahili, the name was chosen with the help of Tanzanian herpetologist John Lyakurwa of the University of Dar es Salaam. An audio recording of the pronunciation of this name is provided on the Natural History Museum's Data Portal.

 

Photographs showing the collection of NHMUK R36620, holotype of Mambawakale ruhuhu, in 1963. Alan Charig is sat in the bottom right of the frame in the top left image, and is accompanied by Alfred ‘Fuzz’ Crompton. The top left and bottom right images also show Tanzanians (names unfortunately not recorded in archival material) who were employed by the 1963 expedition team and were critical to its success, discovering many of the fossil sites, constructing roads and carrying excavated fossils out of the field. Butler et al. (2022).

The specimen from which Mambawakale ruhuhu is described comprises a partial skull including the premaxillae, maxillae, vomers, palatines, pterygoids, ectopterygoids and fragments of the jugals and basipterygoid, with associated hemimandibles, hyoids and isolated maxillary or dentary teeth, found in association with an incomplete postcranium, including an atlantal intercentrum, partial axis and partial third cervical vertebra, a mostly complete left manus, and additional poorly preserved fragments.

 

Photographs of the skull of NHMUK R36620, holotype of Mambawakale ruhuhu, in right lateral (a) and left lateral (b) views, with a close-up of the left premaxilla in lateral view (c). Butler et al. (2022).

The skull was found exposed on an eroded surface. It was in occlusion with the mandibles when found, but apparently separated from them during preparation, during which process several of the teeth were also broken. Both premaxila are present, as are the maxila; the join between these bones is hard to detect visually, but can be seen in CT scans. The region of this join is toothless, creating a gap between the premaxilary and maxilary teeth. Only the lower part of the external naris (nose bone) is preserved, attached to the upper part of the premaxila and surviving part of the maxila, though this is enough to suggest that it was a large structure, extending backwards over at least the first two maxilary teeth; something seen in other Pseudosuchian Archosaurs.  

 

Segmentation based on CT data of the skull of NHMUK R36620, holotype of Mambawakale ruhuhu, in right lateral (a), left lateral (b), anterior (c) and posterior (d ) views, with a medial view of the left side of the skull (e). Abbreviations: afos, antorbital fossa; apmx, ascending process of the maxilla; cut, small part of the fossil that was cut off and not included in the CT scan; en, external naris; fill, area of artificial repair; for, foramen; gr, groove on the lateral surface of the posterodorsal process of the premaxilla; lbpt, left basipterygoid process of the basisphenoid; ljg-lect, left jugal and left ectopterygoid; lmx, left maxilla; lpal, left palatine; lpmx, left premaxilla; lpt, left pterygoid; lv, left vomer; nf, narial fossa; pdp, posterodorsal process of the premaxilla; rbpt, right basipterygoid process of the basisphenoid; rjg-rect, right jugal and right ectopterygoid; rmx, right maxilla; rpmx, right premaxilla; rpt, right pterygoid. Butler et al. (2022).

Small parts of the jugals are preserved, although these are hard to define, even in CT images.The palate is fairly complete, with substantial parts of the vomers, palatines, pterygoids and ectopterygoids all preserved.

 

Photographs of the skull of NHMUK R36620, holotype of Mambawakale ruhuhu, in dorsal (a) and ventral (b) views. Butler et al. (2022).

Both hemimandibles (separately articulated halves of the lower jaw) are preserved, but poorly, and their articulating surfaces are damaged. The dentaries (forward parts of the lower jaw, which bear the teeth) is largely intact. There are fifteen or sixteen teeth on each dentary (the exact count is unclear because of damage to the posterior ends of the tooth rows), although only the roots and a few broken crowns of the teeth are present. 

 

Photographs of the left and right hemimandibles of NHMUK R36620, holotype of Mambawakale ruhuhu. (a)–(d) The left hemimandible and (e)–(h) the right hemimandible in lateral (a), (e), medial (b), (f), dorsal (c), (g) and ventral (d), (h) views. Butler et al. (2022).

The post cranial remains comprise two parts of the hyoid apparatus, three partial cervical vertebrae, and a fairly complete left manus (hand), comprising metacarpals I to IV, the proximal portion of metacarpal V, phalanges of the first digit including an ungual, the first two phalanges of digits II and III, and phalanges 1–4 of digit IV as well as a potential ungual.

 

Left manus of NHMUK R36620, holotype of Mambawakale ruhuhu. Metacarpals in articulation in proximal view (a), dorsal surface directed to the bottom of the image. Manus in dorsal view (b). Digits ordered from I (left) to V (right) in both (a) and (b). Butler et al. (2022).

Resolving the phylogenetic position of Mambawakale ruhuhu proved to be difficult, due to the fragmentary nature of the remains from which the specimen is described, but it appears to be a basal member of the Paracrocodylomorpha. Mambawakale ruhuhu is the largest Archosaur from the Manda Beds described on the basis of cranial remains; a number of similar-sized species have been described from post-cranial remains, but only one Paracrocodylomorph, Mandasuchus tanyauchen, and that is a much smaller Animal, leaving Butler et al. confident that the remains assigned to Mambawakale ruhuhu do indeed represent a new species.

 

Life reconstruction of Mambawakale ruhuhu. Only the skull, mandible and a few postcranial elements are known for Mambawakale ruhuhu, so the rest of the body, tail and limbs are reconstructed based on the anatomy of hypothesised close relatives of similar size. Gabriel Ugueto in Butler et al. (2022).

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Magnitude 5.6 Earthquake off the east coast of Taiwan.

The Taiwan Central Weather Bureau reported a Magnitude 5.6 Earthquake at a depth of 22.8 km roughly 73 km off the eastern coast of Taiwan, slightly before 0.45 am local time on Saturday 12 February 2022 local time (slightly after 4.45 pm on Friday 11 February, GMT). There are no reports of any damage or casualties at this time, but it was felt on the northern and western parts of the island.

 

The approximate location of the 12 February 2022 Taiwan Earthquake. USGS.

Taiwan has a complex tectonic setting, lying on the boundary between the Eurasian and Philippine Plates, with the Eurasian Plate being subducted beneath the Philippine Plate in the South and the Philippine Plate being subducted beneath the Eurasian in the East. Subduction is not a smooth process even in simple settings, with plates typically sticking together as pressure from tectonic expansion elsewhere builds up, then suddenly breaking apart and shifting abruptly, causing Earthquakes.

 

The motion of the tectonic plates beneath Taiwan. The University of Memphis.

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