Wednesday, 31 August 2022

Ceratozamia norstogii: Identifying Animals which disperse the seeds of an Endangered Mexican Cycad.

The genus Ceratozamia comprises about 35 species of neotropical Cycads, all but one of which are found only in Mexico. As such they form an important part of Mexico's botanical diversity, and understanding their ecology and evolutionary history is seen as a key to understanding the climatic history of northern Mesoamerica. 

One of the major steps in understanding the biogeography of any Plant is working out how its seeds are dispersed. This is particularly challenging for Cycads, as their seeds tend to be rather large, and often contain methylazoxymethanol glycosides, which are toxic to most Vertebrates. Nevertheless, most Cycad seeds are thought to be dispersed largely by Rodents and other small-to-medium sized Mammals. 

The seeds of members of the genus Ceratozamia are thought to be particularly toxic, and are therefore presumed to be dispersed largely by gravity. However, this theory has never been put to the test, and it is hard to explain the wide distribution of the genus through gravitational seed dispersal alone.

In a paper published in the Biodiversity Data Journal on 24 August 2022, Héctor Gómez-Domínguez of Senda Sustentable, and Jessica Hernández-Tapia and Andrés Ortiz-Rodriguez of the Departamento de Botánica at the Universidad Nacional Autónoma de México, present the results of an experiment in which two specimens of Ceratozamia norstogii in La Sepultura Biosphere Reserve in Chiapas State, Mexico, were observed by camera trap for ten months in order to assess what Animals were feeding on and spreading their seeds.

Ceratozamia norstogii in the study area. On the left, Plant in reproductive phase (prepollination). Top right, habitat (Pine-Oak forest). On the bottom right, a seedling growing amongst the leaf litter. Héctor Gómez Domínguez & Ana Rocha in Gómez-Domínguez et al. (2022).

Ten months is the time taken from the first appearance of the cones of Ceratozamia norstogii until their disintegration. The cones in La Sepultura Biosphere Reserve were observed over this cycle between October 2020 and July 2021. The first seven months of the growth cycle, October-April, were taken up by the pre-pollination growth phase, during which time the cone reaches its maximum size. The second phase lasts around two months, May-June, and is where pollination occurs. During this phase the cones exude a sweet smelling, amber-coloured liquid which attracts Beetles of the Family Erotylidae (Pleasing Fungus Beetles), known to be important pollinators of Cycads. During the final phase, from June to August, the seeds mature to a brown colour, and are either carried away or eaten by frugivorous Animals, or fall to the ground as the cone disintegrates. 

Female cone maturation. Pre-pollination phase. (A) Emergent cone, with a short, straight peduncle and a general reddish-brown colouration. (B) Young cone, a larger brown cone with a straight peduncle. (C) A large, fully developed cone with a greenish colouration, peduncle much longer and bent towards the ground. Pollination phase. (D) A large, pendant cone, with a light brown colouration, and barely separation amongst megasporophylls. Seed maturation phase. (E) A large, pendant cone, with a light brown colouration and with an evident separation amongst megasporophylls. (F) Mature seeds. Ana Rocha in Gómez-Domínguez et al. (2022).

During the whole ten months, seven Animals were recorded visiting the female cones, the majority of them at night. The daytime visitors comprised three Birds of different species who used the cones as perches during the daytime; two during the immature growing phase, and one while a cone was disintegrating. Also during daylight hours, a Badger was seen to approach a cone, pausing to smell it before leaving. 

During the night, several small-to-medium sized Mammals both visited and interacted with the cones. Most notably, a Mouse of the genus Pteromiscus was observed both feeding on the exudate of the cones, and removing seeds and carrying them beyond the range of the camera, on several occasions. A Kinkajou, Potus flavus, was also seed removing seeds from the cones, although it appeared to be doing this in order to access the central axis of the cone, which it spent some time biting. This is a significant observation for the Kinkajou, a small Mammal usually presumed to live and feed almost exclusively within the tree canopy, but which approached the cone from the ground, but does not appear to have aided the distribution of the Cycad's seeds. Finally, a Southern Spotted Skunk, Spilogale angustifrons, was again observed to bite at the seeds and carry several beyond the reach of the camara.

Female cone visitors of Ceratozamia norstogii. (A) Mouse, Pteromiscus sp., collecting seeds; (B) Southern Spotted Skunk, Spilogale angustifrons, biting the cone and collecting seeds; (C) Kinkajou, Potus flavus, removing seeds. Gómez-Domínguez et al. (2022).

Three species of frugivorous Mammal were observed visiting the cones of Ceratozamia norstogii, all of them at night (after 8.00 pm), with most of the activity happening between 12.00 midnight and 3.00 am. This activity peaked in the second week of July, but carried on for 20 nights, during which time the cones were visited on 65% of nights. The Mouse was the most common visitor, visiting the cone on 13 nights, and making a total of 40 visits. The Southern Spotted Skunk made 15 visits on 3 nights, while the Kinkajou made two visits on a single night. Based upon this, Gómez-Domínguez et al. conclude that the Mouse, Pteromiscus sp., is the most effective distributor of the seeds of Ceratozamia norstogii.

Gómez-Domínguez et al.'s results support the hypothesis that the seeds of Ceratozamia norstogii are distributed by small-to-medium sized Mammals, with the Mouse, Pteromiscus sp., being the most effective distributor. The other two species were less frequent visitors, and were probably feeding opportunistically, rather than using the cones as a regular seasonal food resource. Both are primarily insectivorous, but are also secondarily omnivorous, feeding on smaller Animals, carrion, and fruit. The feeding activity of the Kinkajou was particularly surprising, given that the activities of this Animal are usually restricted to the treetops, but probably not significant for the Cycad. The Southern Spotted Skunk, on the other hand, could potentially be an occasional important seed disperser for this Plant, given that it has a much greater home range than the Mouse, making it likely to carry the seeds for greater distances.

The finding that the seeds of Ceratozamia norstogii are distributed by only a small number of species is consistent with other studies of Cycads, whose seeds are typically dispersed by a small number of, or even a single, species. This contributes to the distribution seen in Cycads, which tend to be found in fairly dense colonies, where it is hard to distinguish between gravity dispersed seeds and seeds dispersed by small Mammals who only carry them a few metres.

This short-distance dispersal is likely to have promoted allopatric speciation (the division of colonies into new species after they become geographically isolated) within the genus Ceratozamia. Within this genus, episodes of speciation appear to have been linked to extinction events in which clades of large Mammals disappeared. This could potentially suggest that the seeds have historically been dispersed over long distances by a variety of large Mammals, but that when these species have gone extinct this role has fallen to smaller Mammals with limited ranges, effectively cutting off the widely dispersed colonies from one-another.

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Tuesday, 30 August 2022

Fishing observed in a Red Fox for the first time.

Red Foxes, Vulpes vulpes, are small mesocarnivorous  found across Eurasia and North America, and introduced to Australia. They are extremely flexible hunters, able to adapt their behaviour to a wide range of prey species. Fish remains have occasionally been found associated with Foxes, but they have never been observed fishing, despite living in close proximity to Humans in many parts of the world, which has led to speculation that they are scavenging Fish rather than actively hunting them.

In a paper published in the journal Ecology on 18 August 2022, Jorge Tobajas of the Departamento de Botánica, Ecología y Fisiología Vegetal at the Universidad de Córdoba, the Instituto de Investigación en Recursos Cinegéticos, and the Biodiversity Research Institute at the University of Oviedo, and Francisco Díaz-Ruiz of the Biogeography, Diversity, and Conservation Research Team at the Universidad de Málaga, describe witnessing a male Red Fox hunting Fish.

The observation was made while Tobajas and Díaz-Ruiz were carrying out fieldwork near the Valuengo reservoir in southern Extremadura, on 24 March 2016. Here, a male Red Fox was observed capturing European Carp, Cyprinus carpio, while they were mating close to the water's edge.

Male Red Fox, Vulpes vulpes, capturing a European Carp, Cyprinus carpio, at the Valuengo reservoir in southern Extremadura, in March 2016. Tobajas & Díaz-Ruiz (2022).

The Fox was observed catching Carp between 1.18 and 2.51 pm, at which point it noticed it was being observed and fled. During this time it made 12 hunting attempts, capturing 10 Fish with an estimated average mass of about 1 kg. This represents a capture success rate of 83%. The Fox was hunting while the Carp were in a reproductive frenzy, and paying little head to the danger present. Fish were captured by simply jumping into the water and grabbing them. After each successful hunt the Fish was carried to a site 20-30 m from the water's edge and buried, hidden, or simply left, presumably for later consumption. The Fox was never observed to eat any substantial part of the Fish, although small parts (possibly eggs?) were consumed on several occasions. At one point a female Fox was observed removing one of the Carp that the male had captured. The male Fox did not challenge this behaviour, suggesting that she was his mate, and that the male was capturing the Fish for the benefit of the female and a litter of pups (unobserved).

Female Red Fox recovering a Fish previously hunted by the male. Tobajas & Díaz-Ruiz (2022).

This observation adds significantly to our understanding of the ecology of the Red Fox, a familiar species generally thought to be well understood, and about which new discoveries would not be expected. It clearly demonstrates that Foxes are highly able hunters of Fish; such a high success rate is unlikely to represent an opportunistic action by a single animal, but is more likely to represent hunting by a Fox with an instinct for such behaviour, which has been further honed through experience.

(a), (b) Two sequences showing the Red Fox, Vulpes vulpes, hunting European Carp, Cyprinus carpio, on the shore of the Valuengo reservoir (southern Extremadura; Spain) during the Carp spawning period, March 2016. (c) European Carp spawning eggs and distracted by the frenzy of reproduction in the shallow reservoir shore. (d) Red Fox carrying a large European Carp far to the shore.(e) European Carp hunted by the Red Fox with the fatal incisions on the head. Tobajas & Díaz-Ruiz (2022).

At first site this observation appeared to represent an incident of 'overkill' by the Fox, i.e. a case of a Fox being presented with an overabundance of easy prey and killing more than it needs to consume out of some sort of misfiring instinct (an explanation often used to justify the hunting of Foxes). However, an animal killing prey which are then consumed by other members of its social unit (such as, in this case, its mate and presumed young) is far from maladaptive. Instead, this appears to be a good use of a seasonally available food resource which coincides with the Fox's own breeding cycle. Similar behaviour has been observed among Arctic Foxes, Vulpes lagopus, which cache large numbers of Bird's eggs in order to feed their young.

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Monday, 29 August 2022

Guangdedendron micrum: A Lycopsid Tree from the Late Devonian of Anhui Province, China.

The first major evolutionary radiation of the Vascular Plants occurred in the Devonian, and was a vital step on the path towards the formation of almost all modern terrestrial ecosystems. During this time, three distinct groups of Vascular Plants began to produce Trees, the Pseudosporochnaleans, Fern-like Plants which may have been related to the true Ferns, Archaeopteridaleans, Fern-like Plants thought to have been ancestral to the Gynosperms, and Lycopsids, or 'Giant Club Mosses'. The Lycopsids are thought to have been the first of these groups to appear, and played an important role in early terrestrial ecosystems, forming the first forests in the Devonian, and dominating the forests of the Carboniferous, providing the majority of the biomass for the great Carboniferous coal deposits. Unlike the Carboniferous forests, the forests of the Devonian are relatively poorly known, with most examples coming from Europe and North America, and only a single example on Svalbard Island having produced in situ Lycopsid trees before 2019.

South China is known to have been a significant centre for the evolution of Lycopsids, and may have been the place where the first forests appeared. In 2019 a Devonian Lycopsid forest was reported at Xinhang in Anhui Province, where trees of the Lycopsid Guangdedendron micrum were uncovered at a working clay pit, yielding the oldest known examples of stigmarian roots.

Because this site is being actively worked for commercial reasons, further fossils are being continuously uncovered, adding to our knowledge of this early forest-forming Lycopsid Tree. In a paper published in the journal BMC Ecology and Evolution on 23 May 2022, Xue Gao of the Key Laboratory of Orogenic Belts and Crustal Evolution at Peking University,  Le Liu of the School of Geoscience and Surveying Engineering at the China University of Mining and Technology-Beijing, Min Qin of the Institute of Geology and Paleontology at Linyi University, Yi Zhou, also of the Key Laboratory of Orogenic Belts and Crustal Evolution at Peking University, Lei Mao of the Anhui Geological Museum, and De‑Ming Wang, once again of the Key Laboratory of Orogenic Belts and Crustal Evolution at Peking University, present an updated description of Guangdedendron micrum, based upon new material that has become available over the last three years.

Guangdedendron micrum was a small Lycopsid Tree, with separate male and female plants, in which adult Plants produced seeds only once before dying. It produced stigmaria-type rhizomous roots, which divided bilaterally on four different axes, and produced helical rootlets. The step branched dichotomously at its terminus, producing a single large strobilus ('cone'). Leaves were narrow with entire margins, and arranged spirally on the stems. The Stobili were typically singular, but in some cases branched dichotomously once. They were roughly cylindrical in shape, with helically arranged megasporophylls (spore bearing leaves), each of which had a keeled pedicel (leaf stem) and an upturned lamina (leaf); spores were born on the upper surface of these laminae.

The rhizomatous roots reached down to about 27 cm beneath the soil surface, with each axes being 8.3-31 cm long, and arranged at angles of 19-60° to the ground surface. The rootlets are up to 27.2 cm long and 7 cm wide. The largest preserved stems are 88 cm high and about 18.7 cm in diameter. The vegetative leaves 2.0-9.2 cm long and 0.12-0.90 cm wide, each having a single vein. The largest stobili reach about 23.4 cm long and 3.0 cm wide. The sporangia laminae reach about 18 mm long and 5.8 mm wide. The megasporangia (spore producing bodies on the leaves are 4.0-7.4 mm long.

The new material presented by Gao et al. shows that the  stigmarian rhizomorph root of Guangdedendron micrum has four evenly distributed axes, which grew to about 31 cm in length, before dichotomously branching once. These rhizomorph roots angle downwards between 19-51° to the ground surface, covering an area up to 41.1 cm wide and 27.0 cm deep. The first order branches (which arise from the initial dichotomous branching) grow to about 7.2-7.8 cm in length, before dividing again to produce third order branches, which reach 2.8-6.5 cm in length. Rootlets are arranged helically along the roots and reach up to 12 mm in length and 5 mm in width. These are generally unbranched, and do not produce root hairs.

In‑situ rooting systems of Guangdedendron micrum from Yongchuan mine. (A) Stem and connected rhizomorph axes. (B) Rooting system with branched rhizomorph axes. PKUB21015. (C) Stems with connected rhizomorph axes bearing rootlets. (D) Top view of the specimen shown in (A), after removing the stem and surrounding rocks partially peeling off. A rooting system with four once‑dichotomized rhizomorph axes. Arrows indicating 8 second‑order branches. (E) Stem base and connected two rhizomorphic axes. (F), (G) Rhizomorphic axes connected to moulds of stem bases and bearing rootlets. Scale bars: (B), (D), (G) 5 cm; diameter of the coin for scale: 2 cm (A), (C), (E), (F). Gao et al. (2022).

Stems have been found preserved as compressions and erect casts. These reach up to 71.3 cm high and 1.1-12.2 cm in diameter, excluding the expanded bases which form the connection to the root system. Dichotomous branching is rare, but does occur, happening no more than twice on a single plant, with the branches angled at 13-43°. 

Stems and vegetative leaves of Guangdedendron micrum, from Yongchuan (A), (B), (D), (G)–(M), (O)–(Q), (S), (U), (V) and Jianchuan (C), (E), (F), (N), (R), (W) mines. (A), (B) In‑situ stems with expanded bases. PKUB21000, 21014. (C) Two adjacent in‑situ stems with expanded bases. (D) An in‑situ stem with an expanded base. (E), (F) Two sides of a stem displaying basal expansion and helically arranged oval fissures of broken leaf cushions after leaf abscission. PKUB21004. (G)–(J) Stems perpendicular to the bedding plane. (H) YC‑103. (K) An in‑situ stem with leaf cushions. (L) A once‑dichotomised stem. YC‑101. (M), (N) Twice‑dichotomised stems. (M) YC‑102. (O) A once‑dichotomised leafy stem with leaf bases. (P), (Q) Part and counterpart of helically arranged leaf cushions. YC‑105, 104. (R) A stem with helically arranged leaf cushions. (S) Fusiform leaf cushions. PKUB21013. (T) Line illustration of a leaf cushion based on arrowed portion in (Q). (U) Helically arranged leaf bases. Arrow indicating portion enlarged in (V). PKUB21007. (V) Enlargement of arrowed portion in (U), indicating fusiform leaf bases with middle vertical grooves in the lower part. (W) Helically arranged leaf bases, each showing a vertical groove in the middle. PKUB16052a. Scale bars: (A), (E), (F) 2 cm, (D), (G) 5 cm, (P)–(R), (U), (W) 1 cm, (S), (T), (V) 5 mm; diameter of the coin for scale: 2 cm (B), (C), (H), (J), (K), (M)–(O); length of the hammer for scale: (I) 28.6 cm, (L) 27.3 cm. Gao et al. (2022).

Vegetative leaves are 3.5-8.5 cm long and 0.29 to 0.90 cm wide, and spindle-shaped with entire margins and a single vein running the entire length of the leaf. These are arranged spirally around the stems, departing at an angle of 59-98° to the stem. Slender twigs, interpreted as the stems of juvenile plants, have leaves to their tips arranged in a similar way.

Vegetative leaves of Guangdedendron micrum from Jianchuan mine. (A), (B) Terminal parts of vegetative axes bearing leaves. PKUB21001, 16067. (C), (D) Part and counterpart of a terminal vegetative axis. PKUB21017a, 21017b. (E), (F) Tapering vegetative axes with persistent linear leaves. Arrow indicating portion in (F) enlarged in (G). PKUB21018, 16144. (G) Enlargement of arrowed portion in (F), showing veins of vegetative leaves. Scale bars: (A)–(E) 2 cm, (F) 10 cm, (G) 1 cm. Gao et al. (2022).

The fertile stems are up to 6.4 cm long and 0.21-0.55 cm wide, and tipped by strobili. One fertile stem found was 17.6 cm wide, and branched dichotomously, producing two daughter stems angled at 60° to one-another. Vegetative leaves on the lower part of the fertile stems are angled at 70-85° to the stems, and are curved at their tips.

Fertile axes and strobili of Guangdedendron micrum from Jianchuan (A)–(E), (H)–(J), (L), (M) and Yongchuan (F), (G), (K) mines. (A), (B) Part and counterpart of a once‑dichotomized axis bearing linear leaves and a single strobilus. (C) A strobilus without basal fertile axis preserved. (D), (E) Part and counterpart of a strobilus terminating a fertile axis. PKUB16001a, 16001b. (F), (G) Part and counterpart of terminal strobili in pairs, with sporophylls along central strobilar axis and persistent vegetative leaves on fertile axis. PKUB21002a, 21002b. (H) At least eight strobili (arrows 1–8) preserved in the same direction (1 and 2, 7 and 8 possible paired, respectively). PKUB16047. (I) A dichotomized strobilus. PKUB21011. (J) Terminal strobili in pairs. PKUB16035. (K) A single and a pair of strobili perpendicular to the layers. (L) A short strobilus may partially preserved. PKUB16065. (M) Strobilus displaying central strobilar axis. PKUB16020a. Scale bars: (A), (B) 5 cm, (C), (J), (L), (M) 1 cm, (D)–(I) 2 cm; diameter of the coin for scale: 2 cm (K). Gao et al. (2022).

The strobili at the end of the fertile stems are pendulous and usually singular, although they are sometimes found in pairs and occasionally branch dichotomously. They are cylindrical and slightly curved, reaching a maximum of about 23.4 cm in length. Sporophylls are tightly packed and helically arranged around these strobili. Each sporophyll comprises a pedicel projecting horizontally from the main stem, and a lamina angled at about 110° to this pedicel. These laminae are an elongated triangle shape, reaching 12-18 mm in length.

Stems and strobili of Guangdedendron micrum from Jianchuan (A)–(G), (I), (L)–(O) and Yongchuan (H), (K), (P), (Q) mines. (A), (B) Two sides of a stem with expanded base and leaf cushions. PKUB21005. (C), (D) Two sides of a stem. PKUB21006. (E), (F) In-situ once-dichotomized stems. Two arrows in (E) indicating two daughter axes. (G) Oval fissures helically arranged along stem. (H) Oval fissures helically arranged along in-situ stem. (I) Enlargement of portion of stem (arrow), showing a ligule pit (Lp) and a vascular bundle scar (Vs). (J) Interpretative line drawing of helically arranged leaf bases, indicating outlines (black lines) and parastichies (red dotted lines) of leaf bases. PKUB16049. (K), (L) Dichotomised fertile axes with terminal single strobilus. (M), (N) Terminal strobili in pairs. PKUB16097, 16099. (O) Dichotomised fertile axis with partially preserved strobili. (P) Over ten strobili preserved in the same direction. (Q) A possibly once-dichotomized strobilus. Scale bars: (A)–(D) 5 cm, (F), (L) 2 cm, (G), (M)–(O), (Q) 1 cm, (I) 2 mm, (J) 5 mm; diameter of the coin for scale: 2 cm (E), (H), (K), (P). Gao et al. (2022).

All of the strobili found produce megaspores (i.e. female spores), leaving the possibility that the male plants were quite different. Each sporaphyll has an ellipsoidal megasporangium 4.0-7.4 mm in length on its upper surface. Few of these can be seen clearly, as the upper surfaces are generally covered by the adjacent sporaphylls, but each megasporangium appears to contain multiple megaspores.

Sporophylls and spores of Guangdedendron micrum from Jianchuan mine. (A) A partially preserved strobilus, showing sporangia on the adaxial surface of sporophyll pedicels. PKUB16049. (B) A partially preserved strobilus, showing megaspores and sporophylls. PKUB16141. (C) Mid‑upper part of a strobilus with helically arranged sporophylls in face and lateral view. Arrow indicating portion enlarged in (H). PKUB16058. (D) Enlargement showing sporophyll laminae and pedicel in lateral view. (E) Enlargement showing sporophyll laminae and pedicel in lateral view and partially preserved sporangia, arrows indicating megaspores. (F) Enlargement of arrowed portion in (A), showing sporangia. (G) Enlargement showing sporophyll laminae in face view. (H) Enlargement of portion in (C) (arrow), showing sporophyll laminae in face view with downturned heels. (I) Part of a strobilus showing megaspores, the arrow indicating portion enlarged in (K). PKUB16020a. (J), (K) Enlargement showing megaspores and spiny ornamentations. (L) Megaspores with spiny ornamentations. Scale bars: (A), (C), (D) 1 cm, (B), (F) 5 mm, (E), (G)–(I) 2 mm, (J) 1 mm, (K), (L) 500 μm. Gao et al. (2022).

The absence of strobili producing microspores in the discovered specimens of Guangdedendron micrum is curious, particularly as a large number of specimens have now been found. Other Lycopsid species from the Devonian and Carboniferous are known have produced microsporangia and megasporangia on separate, but otherwise similar plants. It is possible that male Guangdedendron micrum plants were much less common than the female plants, or that the plants were able to reproduce parthenogenicly from unfertilised megaspores. 

Reconstruction of the longest strobilus terminating the fertile axis after bifurcation. Scale bar is 2 cm. Gao et al. (2022).

Bifurcation (spliting in two) of the fertile stems and strobili of Lycopsids is rare, but has previously been recorded in other Late Devonian species. This appears to be caused by branching of a meristem (growth centre of a Plant) at the tip of the stem after the stem has switched to its fertile growth mode. In Guangdedendron micrum this can occur before the strobili, resulting in paired strobili, or on the strobilus itself, resulting in a forked strobilus. A similar branching can be seen in the fertile zones of some living Club Mosses and Ferns, although these are all epiphytic in habit, and it has generally been assumed that this is an adaptation to that lifestyle; something highly unlikely in Guangdedendron micrum, which has a well developed subterranean root system, and is in any case the largest Plant in its ecosystem.

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Landslide kills family of five in Kerala State, India.

Five members of a family have died after a landslide swept their house away in Kerala State, India, on Monday 29 August 2022. The incident happened in the village of Kudayathoor, in Idukki District, at about 4.15 am local time, following heavy rains overnight associated with the seasonal monsoon. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall.  

Rescue workers recover the body of a woman who died when a landslide struck her family home in the village of Kudayathoor in Kerala State, India, on 29 August 2022. Reju Arnold/On Manorama.

The deceased have been identified as homeowner Chittadichaalil Soman, his mother Thankamma (74), his wife Shiji, their daughter Shima (25), and her son Devanand (4), with all the bodies recovered within five hours of the original incident. The area is still thought to be unstable, presenting a risk to nearby households, and local authorities are assessing the need to evacuate the entire community.

Monsoons are tropical sea breezes triggered by heating of the land during the warmer part of the year (summer). Both the land and sea are warmed by the Sun, but the land has a lower ability to absorb heat, radiating it back so that the air above landmasses becomes significantly warmer than that over the sea, causing the air above the land to rise and drawing in water from over the sea; since this has also been warmed it carries a high evaporated water content, and brings with it heavy rainfall. In the tropical dry season the situation is reversed, as the air over the land cools more rapidly with the seasons, leading to warmer air over the sea, and thus breezes moving from the shore to the sea (where air is rising more rapidly) and a drying of the climate.

Diagrammatic representation of wind and rainfall patterns in a tropical monsoon climate. Geosciences/University of Arizona.

Kerala has a complex seasonal cycle, driven by the presence of the Western Ghats mountain range, which largely block the dry northerly winds which dominate the climate of much of India, and its proximity to the equator, which leads to a double monsoon system. Such a double Monsoon Season is common close to the equator, where the Sun is highest overhead around the equinoxes and lowest on the horizons around the solstices, making the solstices the coolest part of the year and the equinoxes the hottest. In Kerala this results in a Southwest Monsoon, which lasts from May to September, and is driven by winds from the southern Arabian Sea dumping water onto the Western Ghats, followed by a Northwest Monsoon, which lasts from October to December, where winds from the Bay of Bengal do the same. Of the two monsoons, the southwest is the wetter, due to the proximity of the sea, with June typically being the wettest month, with an average of 341 mm of rain falling in the month

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Asteroid 3 Juno comes to opposition.

Asteroid 3 Juno will reach opposition (the point at which it is directly opposite the Sun when observed from the Earth) at 7.10 pm GMT on Wednesday 7 September 2022, when it will also be at the closest point on its orbit to the Earth, 1.31 AU (i.e. 31 times as far from the Earth as the Sun, or about 195 422 000 km), and be completely illuminated by the Sun. While it is not obvious to the naked eye observer, asteroids have phases just like those of the Moon; being further from the Sun than the Earth, 3 Juno is 'full' when directly opposite the Sun. As 3 Juno is only about 247 km in diameter, it will not be visible to the naked eye, but with a maximum Apparent Magnitude (luminosity) of 7.8 at opposition, it should be visible in the Constellation of Aquarius to viewers equipped with a good pair of binoculars or small telescope, with the best visibility being at about midnight from anywhere on Earth.

The calculated orbit and position of 3 Juno on 7 September 2022. In The Sky.

Asteroid 3 Juno was discovered on 1 September 1804 by German astronomer Karl Harding, making it the third asteroid ever discovered. It was named Juno in honour of the Roman goddess Juno, wife of Jupiter. Juno is thought to be one of the 20 largest bodies in the Main Asteroid Belt, containing about 1% of all the mass in the Asteroid Belt, and is one of the two largest stony (S-type) asteroids, along with Asteroid 15 Eunomia.

3 Juno has a 1594 day (4.36 year) orbital period and an eccentric orbit tilted at an angle of 13.0° to the plane of the Solar System, which takes it from 1.98 AU from the Sun (i.e. 198% of the average distance at which the Earth orbits the Sun) to 3.36 AU from the Sun (i.e. 336% of the average distance at which the Earth orbits the Sun). As an asteroid that never comes within 1.666 AU of the Sun and has an average orbital distance less than 3.2 AU from the Sun, 3 Juno is classed as a Main Belt Asteroid. 

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Sunday, 28 August 2022

Kundakhai Hill: A Middle Palaeolithic site in the Southern Bargarh Uplands of Odisha State, India

The appearance of Middle Palaeolithic stone tool industries is generally associated with the spread of Anatomically Modern Humans out of Africa and into areas of Eurasia previously occupied by other Hominins. Thus, these stone tools are considered important indicators for the spread of Anatomically Modern Humans in areas where actual fossil evidence is absent. A large number of Middle Palaeolithic sites are known from India, with age ranges dating from about 350 000 to about 40 000 years ago. Efforts have been made to subdivide this long time period into early, middle, and late phases based upon the technology used, but it is unclear if this represents an accurate reflection of cultural development in the region, or local variations in tool selection from a common cultural kit which persisted over the whole period.

While in many parts of India, Middle Palaeolithic sites have been known since the mid-nineteenth century, the first such localities in Odisha State were not discovered until the 1960s-70s, when a series of Middle Palaeolithic sites were uncovered in the Brahmani, Baitarani, and Sabarnarekha river drainage systems in the north of the state. Subsequent research uncovered several more sites in the 1980s, but since this time little archaeological work on Middle Palaeolithic sites has been carried out in this area.

In a paper published in the Journal of Anthropological and Archaeological Sciences on 13 July 2022, Pradeep Behera and  Kshirasindhu Barik of the Department of History at Sambalpur University, describe a new Middle Palaeolithic site at Kundakhai in the the Southern Bargarh Uplands of western Odisha.

Over the last decade a series of archaeological investigations in the Bargarh Uplands have uncovered a series of Late Acheulian-Middle Palaeolithic sites, within the area 20-25 km to the south of the Debrigarh-Lohara Massif, with stone tools made primarily from quartzite, chert, and quartz derived from the massif. Subsequent investigations in the southwestern Bargarh Uplands uncovered a series of Middle-Late Palaeolithic and Microlithic (Mesolithic) sites, suggesting persistent inhabitancy of this region throughout the Middle-Late Pleistocene. One of the most important sites uncovered during these surveys is at Kundakhai, a site located on a inselberg (hill of volcanic rock), which appears to have served as a manufacturing site for Middle Palaeolithic tools.

The study area in the Southern part of Bargrh upland in the middle course of the River Ong. Behera & Barik (2022).

The site is located on a flank of the hill, at an altitude of 204 m above sealevel, about 1.5 km to the south of the village of Kundakhai. The hill itself rises to 217 m above sealevel, and is surrounded by agricultural land. Extensive investigations yielded no further archaeological material within the area, although the artefacts found come from an exposure where an Earth road joins a main road, and it is possible that further material was lost during the construction of the road.

Artefact scatters found on the foothill of the sampled area of the Kundakhai hill. Here some of the artefacts are found embedded in a deposit of coarse clast in a lateritic matrix. Behera & Barik (2022).

The hill is largely comprised of dykes of silicified rock which intruded into a (now largely eroded away) granite. The hill has only a sparse covering of vegetation, and several large boulders, with derived weathering products, are visible at the top. A dense scatter of Middle Palaeolithic tools was visible on the surface beside the junction between the roads, with subsequent investigations revealing the presence of more tools within a layer exposed by the road cut, which comprised angular cobbles within a laterite matrix.

An exposed section on the southern flank of the Kundakhai hill showing artefacts embedded in matrix of secondary laterite with coarse clast/hill cobbles. Behera & Barik (2022).

A few artefacts were also found on the top of the hill, and the the flank beneath it, although the majority were found by the roadcut at the hill's base. Artefacts were collected from across the site by walking the surface and recording their position with a GPS unit.

A view of the top of the Kundakhai hill with exposed bedrocks of huge, silicified boulders. Behera & Barik (2022).

The most common lithic artefacts were wastage (waste material produced during tool manufacture), which formed 35.8% of the material present, and debitage (flake blades produced by the reduction of a core), which represented 32.67% of the total material. This was followed in abundance by cores (15.87% of the material), shaped tools (15.41%), and hammers with battering marks (0.23%). 

Despite probably having been washed down the hill, and disturbed by the recent road-making process, most of the artefacts are intact, with broken tools largely represented by blades broken close to their tips. Only three of the 137 cores found were broken.

The majority of the artefacts found at Kundakhai are made from rock identical to the silicious boulders which outcrop on the top of the hill, and these boulders show marks made by hammering, strongly supporting the idea that the hill was a manufacturing site. A smaller number of tools (about 6%) are made from milky quartz, chert, or quartzite, apparently imported from the banks of the River Ong, 7-8 km away, and its tributaries the Ghensali and Utali, with all material originating less than 25 km from the site.

A closer view of some of the silicified bedrocks on the top of the hill showing removal of large flakes with hard hammer percussion. Behera & Barik (2022).

Eight different types of core were identified at the Kundakhai site, which Bahera and Barik identify as Levallois cores, discoidal cores, non-Levallois flake cores, flake-blade cores, flake-bladelet cores, blade-bladelet cores, blade cores, and bladelet cores. Although there are a few blade-bladelet cores which were probably used as tools in their own right, the majority of these cores would have been used to produce flakes for use as blades (it is possible to tell a core has been used in this way by the scars on the blank removal surface). The majority of the cores are oval in shape, but highly variable in size - with the exception of the Levallois cores, which are symmetrical in shape and consistent. 

Different Levallois core from the sampled area-Recurrent Levallois Core (1)-(4), Preferential Levallois Core (5)-(6), Discoidal Core (7)-(8). Behera & Barik (2022).

The site did not yield any cores with rounded cortical surfaces, which are formed by the working of large pebbles and cobbles from riverbeds, suggesting that such rocks were not used. The most abundant cores were the Levallois cores, followed by discoidal cores. Of the remainder, the most common type were single platformed cores, followed by opposed platform opposed face cores, then opposed platform same face cores. 

Different non-Levallois core from the sampled area-Flake/Blade Core Single Platform (1), Opposed Platform Opposite Face Flake Core (2), Single Platform blade & Bladelet Core (3), Single platform Flake Core (4). Behera & Barik (2022).

The debitage material comprises 197 flakes, 20 blades, and two bladelets. About 30% of this material has been broken, mostly near the tip, and almost all of it apparently during manufacture rather than use. The commonest flake type are Toth's Type-VI (so named because the classification system was developed by American archaeologist Nicholas Toth), with the remainder being Toth's Type-II-IV. Levallois flakes mostly range from 40 to 60 mm in length, while non-Levallois flakes mostly range from 20 to 50 mm in length. No flakes measure longer than 90 mm.

The large thick flakes hammered from the rocks at the top of the hill appear to have been used to make cores for blank production; more than half of the cores present have been made from such flakes. These cores are most commonly unfaceted (44.79% of the time), followed by faceted (23.44%), dihedral (8.33%), and punctiform (2.6%). 

Excluding the Levallois flakes, the approach to tool-making appears to have been quite flexible, resulting in a wide variety of flake and core shapes, and suggesting tools were probably being made specifically to the job in hand. Two Kombewa flakes and two possible Kombewa flakes were found among the assemblage, although no Kombewa cores were found.

The vast majority of finished tools present at the Kundakhai site are made from modified flakes, predominantly non-Levallois flakes, but with some tools made from Levallois flakes, as well as a small number of modified cores, and a single, unfinished handaxe. The majority (61%) of the modified flakes are scrapers, with some notched tools (thought to have been used in woodworking), a few of which are of the Clacktonian type.

Different types of tools made on Silicified stone. (1) Side Scrapper, (2) Levallois Point, (3) Denticulate, (4) Concave Side Scrapper, (5)-(7) & (9)-(11) Blades, including (5) Offset Dihedral Burin, (7) Partially baked & Unilaterally Retouched on Ventral Side, (8) Bladelet, (9)-(11) Partially retouched Laterals. Behera & Barik (2022).

Awls and burins are both also present, sometimes in combination with scrapers or notched tools. Some points are present, mostly typical and atypical Levallois points, but with one retouched point and one tanged point also found; the tanged point is bilaterally prepared, but lacks the convergent distal end typical of the Indian Middle Palaeolithic. 

(1) Pseudo Levallois Tanged point, (2) Levallois Point, (3) Transverse Scrapper. (4)-(8) Levallois Flakes, (9) Non Levallois Bidirectional Flake. Behera & Barik (2022).

The single handaxe present at the site is made from a piece of greyish-black chert, clearly not sources from Kundakhai hill, and probably sourced from the  Ghensali or Utali streams, where similar clasts are present having been carried from the source of the streams in the  Jhanj-Malaikhaman hills. The axe is 193.83 mm in length and 83.25 mm in width, and appears unfinnished, with the but being unmodified and the tip broken off, possibly suggesting that the attempt at tool-making was abandoned. 

Hand Axe. Behera & Barik (2022).

A number of archaeological sites have previously been found in the Northern Bargarh Uplands, yielding Late Acheulian-Middle Palaeolithic tools. One of these, Torajunga, has produced a particularly extensive Middle Palaeolithic tool set, including medium sized handaxes and cleavers, scrapers, notched tools, denticulates, spheroids, and tanged points. The other sites contain smaller selections of tools from the same kit, and are often exposed at the surface, and in less than pristine condition.

Hammer Stone with use marks. Behera & Barik (2022).

The Kundakhai site was discovered during a systematic survey of the Southern Bargarh Uplands, which aimed to find similar sites to those already known to the north. This survey yielded several sites with small surface scatterings of Middle Palaeolithic tools, and a few examples of Early Palaeolithic material, as well as mapping outcrops of rock likely to have been useful to Palaeolithic toolmakers. 

The majority of the tools present at Kundakhai appear to have been made at the site from the silicious rock which outcrops here, with only a very small proportion made from imported chert or quartzite. The site lacks many of the tools present in the Northern Bargarh Uplands, including small to medium sized hand axes and cleavers, picks, polyhedrons, well-organised blade core technology, well-made tanged points, but shares other features, most notably Levallois tools, discoidal cores, scrapers and denticulate tools, all of which are also well known from Middle Palaeolithic sites elsewhere in India. 

The apparently long length of the Indian Middle Palaeolithic has led to attempts to divide it into phases. Typically three phases are used, with the first still retaining many Acheulian tools, the second based around a core-reduction technology, and the third more focused on blades, although the evidence that this is an accurate reflection of change over time in the region is absent. If this scheme is used, then the assemblage at Kundakhai, dominated by cores and core-derived tools, belongs firmly in the second phase, although this assessment cannot be used to guess the age of the site.

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