Sciency Thoughts: Medog County

Showing posts with label Medog County. Show all posts

Thursday, 13 July 2023

Selaginella densiciliata: A new species of Spikemoss from Medog County, Tibet.

The Lycophytes were one of the first groups of Vascular Plants to emerge in the Silurian, and remained one of the dominant Plant groups throughout the Palaeozoic. Lycophytes reproduce by means of spores, have vascular tissue, unlike True Mosses, Hornworts, and Liverworts (although this is arranged in a different way to all other Vascular Plants), but unlike other Vascular Plants lack true leaves, instead having microphylls, short flattened stems which form a scale-leaf with unbranching veins. The most notable fossil members of this group are the giant Lepidodendrales trees which dominated the coal forests of the Carboniferous. Today this group is represented by only a few species of Clubmosses, Spikemosses, and similar forms. The genus Selaginella has a fossil record dating back to the Late Carboniferous, and is the sole surviving genus of Spikemoss, with representatives found in tropical forests around the world.

In a paper published in the journal PhytoKeys on 7 June 2023, Shao-Li Fang of the School of Ecology and Environmental Science & School of life Sciences at Yunnan University, Bo Xu of the Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and the Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province at the Chengdu Institute of Biology, Liang Zhang of the Key Laboratory for Plant Diversity and Biogeography of East Asia at the Kunming Institute of Botany, and Zhao-Rong He and Xin-Mao Zhou, also of the School of Ecology and Environmental Science & School of life Sciences at Yunnan University, describe a new species of Selaginella from Medog County in southern Tibet.

Medog County is located in the southeast of Tibet, forming part of the Eastern Himalaya Biodiversity Hotspot, along with Bhutan, most of Nepal, and parts of north and northeast India. The county is considered to be one of the most biodiverse in China, with more species discovered there in 2020 than any other county in the country.

During fieldwork in June 2015 and October 2017, specimens of a Spikemoss which did not conform to any known species were collected from a broad-leaved evergreen forest, at an elevation of 1600 m, close to the township of Beibeng. These were later confirmed to be a new species by DNA analysis. The new species is named Selaginella densiciliata, where 'densiciliata' means densely ciliated, in reference to the sterile (non-spore bearing) microphylls of the Plant, which have a dense covering of cilia.

Selaginella densiciliata. (A) Dorsal view of branches. (B) Ventral view of branches with strobili. (C) Ventral view of branches, showing rhizophores, axillary leaves, and ventral leaves. (D) Dorsal view of branches, showing dorsal leaves. (E) Ventral view of branches, showing axillary leaves, and ventral leaves. (F) Dorsal view of strobilus. (G) Ventral view of strobilus. (H) Axillary leaf on stems (left) and branches (right). (I) Dorsal leaf. (J) Ventral leaf. (K) Dorsal sporophyll. (L) Ventral sporophyll. (M) Proximal surface of megaspore. (N) Distal surface of megaspore. (O) Proximal surface of microspore. (P) Distal surface of microspore. Fang et al. (2023).

Selaginella densiciliata is a terrestrial evergreen herbaceous Plant reaching 7-15 cm in height. The main stem is unbranching for 0.5-3.5 cm, then produces 6-13 pairs of pinately dividing branches. Four rows of sterile microphylls are present from the base to the middle of the stem.

Monday, 23 January 2023

Avalanche kills at least 28 in Tibet.

At least 28 people have died following an avalanche in southeast Tibet on Friday 20 January 2023. The incident happened at about 8.00 am local time, when several tonnes of snow slid onto a section of highway between the village of Pai in Mainling County and the Doxong La Tunnel in Medog County, burying dozens of cars carrying people trying to get to family homes for the Lunar New Year celebrations. Rescue workers now believe they have found all of the vehicles hit by the snow, with fifty three people having been found alive, five of them with serious injuries, while the bodies of 28 people who did not survive the event were also found.

Rescue workers searching for survivors following an avalanche in southeastern Tibet on Friday 20 January 2023. CCTV.

Avalanches are caused by the mechanical failure of snowpacks; essentially when the weight of the snow above a certain point exceeds the carrying capacity of the snow at that point to support its weight. This can happen for two reasons, because more snow falls upslope, causing the weight to rise, or because snow begins to melt downslope, causing the carrying capacity to fall. Avalanches may also be triggered by other events, such as Earthquakes or rockfalls. Contrary to what is often seen in films and on television, avalanches are not usually triggered by loud noises. Because snow forms layers, with each layer typically occurring due to a different snowfall, and having different physical properties, multiple avalanches can occur at the same spot, with the failure of a weaker layer losing to the loss of the snow above it, but other layers below left in place - to potentially fail later.

Diagrammatic representation of an avalanche, showing how layering of snow contributes to these events. Expedition Earth.

Wednesday, 24 April 2019

Magnitude 5.9 Earthquake in Arunachal Pradesh, India.

The United States Geological Survey recorded a Magnitude 5.9 Earthquake at a depth of 14 km about 33 km to the north of the town of Aalo in West Siang District, Arunachal Pradesh, India, at about 1.45 am local time on Wednesday 24 April 2019 (about 8.15 pm on Tuesday 23 April GMT); the same Earthquake was measured by the China Seismological Network as a Magnitude 6.3 event at a depth of 10 km in Medong County, Tibet, which occured at a 4.15 am local time (this difference is caused by China and India both having a single standard time zone, with the effect that the focal points detected by the two agencies, while only a few km apart, are in time zones with a difference of three hours). The event was felt across northeastern India, as well as in China, Myanmar, Bangladesh, Bhutan, and Nepal, though there are no reports of any damage or casualties.

The approximate location of the 6 December 2017 Tibet Earthquake. USGS.

Earthquake activity in the area is caused by the uplift of the Tibetan Plateau, due to the impact of India into Eurasia to the south. he Indian Plate is moving northwards at a rate of 5 cm per year, causing it to impact into Eurasia, which is also moving northward, but only at a rate of 2 cm per year. The collision of the Indian and Eurasian plates has lead to the formation of the Himalayan Mountains, the Tibetan Plateau, and the mountains of southwest China, Central Asia and the Hindu Kush.

Block diagram showing how the impact of the Indian Plate into Eurasia is causing uplift on the Tibetan Plateau. Jayne Doucette/Woods Hole Oceanographic Institution.

Much of northern India and neighbouring areas of Central Asia and the Himalayas, are prone to Earthquakes caused by the impact of the Indian Plate into Eurasia from the south. When two tectonic plates collide in this way and one or both are oceanic then one will be subducted beneath the other (if one of the plates is continental then the other will be subducted), but if both plates are continental then subduction will not fully occur, but instead the plates will crumple, leading to folding and uplift (and quite a lot of Earthquakes). The collision of the Indian and Eurasian plates has lead to the formation of the Himalayan Mountains, the Tibetan Plateau, and the mountains of southwest China, Central Asia and the Hindu Kush.

The movement of India into Eurasia over the last 71 million years. USGS.

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.

See also...

https://sciencythoughts.blogspot.com/2018/06/landslide-kills-four-in-arunachal.html

https://sciencythoughts.blogspot.com/2017/11/magnitude-64-earthquake-in-eastern-tibet.html

https://sciencythoughts.blogspot.com/2017/07/flooding-kills-at-least-seventy-three.html

https://sciencythoughts.blogspot.com/2017/07/fourteen-feared-dead-after-landslide-in.html

https://sciencythoughts.blogspot.com/2016/04/sixteen-dead-after-landslide-in.html

https://sciencythoughts.blogspot.com/2014/06/magnitude-45-earthquake-in-northeast.html

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Sunday, 30 September 2018

Begonia medogensis: A new species of Begonia from Tibet and Myanmar.

Begonia, Begonia spp., are perennial flowering plants related to Gourds, found in tropical and subtropical forests around the world, and popular as houseplants. They are typically ground-dwelling understory Plants, though some species are epiphytes (live on other Plants, usually in the canopy of trees). Begonias are monoecious, with both male and female flowers occurring on a single plant, and may be upright-stemmed, rhizomatous or tuberous.

In a paper published in the journal PhytoKeys on 2 July 2018, Jian-Wu Li of the Center for Integrative Conservation at the Xishuangbanna Tropical Botanical Garden, Yun-Hong Tan, also of the Center for Integrative Conservation at the Xishuangbanna Tropical Botanical Garden, and of the South Asia Biodiversity Research Institute of thr Chinese Academy of Sciences, Xi-Long Wang of the Tibet Plateau Institute of Biology, Cheng-Wang Wang of the School of Life Sciences at Nanchang University, and Xiao-Hua Jin of the Institute of Botany of the Chinese Academy of Sciences, describe a new species of Begonia from Medog County in Tibet and the Putao District of Kachin State in Myanmar.

The new species is named Begonia medogensis, meaning 'from Medog', as it was first identified in a subtropical semi-evergreen forest in Medog County, Tibet, and later found in a tropical montane forest in the Putao District of Kachin State in Myanmar. It is an erect rhizomatous perennial herb reaching up to a metre in height, with hairy, oval-to-lance-shaped leaves growing directly from the stems. It produces bracts of flowers from October to December, each of which bears 1-5 pink and white flowers, all of the same sex.

Begonia medogensis. Jian-Wu Li in Li et al. (2018).

Thursday, 14 May 2015

Sarothrias sinicus: A new species of Jacobsonid Beetle from Tibet.

Jacobsonids are a small group of minute elongate yellowish brown Beetles, of uncertain taxonomic placement; different entomologists feeling that the group are more closely related to different groups of Beetles. The family is split into three genera with a total of 21 described species, the largest genera, Sarothrias, currently containing thirteen species, twelve of which are found in equatorial regions from the Seychelles and South India to the west to Australia and Fiji in the east, with the one non-equatorial species being found in northeast India.

In a paper published in the journal ZooKeys on 16 April 2015, Wen-Xuan Bi of the Key Laboratory of Zoological Systematics and Evolution at the Institute of Zoology of the Chinese Academy of Sciences, Chang-Chin Chen of the NPS office of the Tianjin New Wei San Industrial Company, Limited and Mei-Ying Lin, also of the Key Laboratory of Zoological Systematics and Evolution at the Institute of Zoology describe a new species of Sarothrias, from Medog County in Tibet.

The new species is named Sarothrias sinicus, meaning ‘Chinese’, as it is the first member of the genus or family known from China. The species is described from a single male specimen, 2.2 mm in length and dark brown in colour, collected from subtropical evergreen broadleaf forest at an altitude of 1850 m.

Sarothriassinicus, male specimen in (1) dorsal, (2) ventral and (3) lateral views. Scale bar is 0.5 mm. Bi et al. (2015).

Tuesday, 10 February 2015

A new species of Grass Moth from Tibet.

Grass Moths, Crambidae, are generally small and inconspicuous, particularly when in a resting posture, with rolled wings on a Grass stem, though they are a variable group and some species are quite conspicuous. Most well studied members of the group are of economic importance, generally as pest species (the larvae are stem-borers, mainly of Grasses), though some species are used as controls of invasive plants, and one - the Bamboo Borer, Omphisa fuscidentalis, is used for Human consumption.

In a paper published in the journal ZooKeys on 22 January 2015, Wei-Chun Li and Dong Liu of the College of Agronomy at Jiangxi Agricultural University, describe a new species of Grass Moth from Galongla Mountain in Medog County, Tibet.

The new species is placed in the genus Metaeuchromius, which is found across North and East Asia, and given the specific name glacialis, in reference to the glaciers found in the immediate proximity of the area where it was discovered. The species is described from five male specimens attracted to a mercury lamp, which was being used to attract Moths as part of a study into the wildlife of the glacial regions of Tibet, which is considered to be under threat due to global warming.

Metaeuchromius glacialis, male in dorsal view. Li & Lui (2015).

The Moths are largely white, with darker markings on their forewings, thorax and heads. The forewings are 9-10 mm in length. The male moths were active in late July, and were collected at an altitude of 3415 m; their natural history is otherwise unknown.

The area where the specimens were collected, at the foot of Galongla Mountain. Li & Lui (2015).