#macrofossil

[dropsofsciencenews]

A Record-Breaking Old Bean

ESP version ITA version

Can a seed be among the largest ever recorded in the fossil record, represent the first evidence of migration between tectonic plates towards the Australian region, and also be the only known ancestor of the Moreton Bay chestnut (Castanospermum australe)?

The answer is a resounding yes.

Who are we talking about? Its name is Jantungspermum gunnellii, a leguminous plant dating back to the Eocene period, approximately 34-40 million years ago. The discovery of this plant was the result of extreme determination and, perhaps, a bit of luck. Collecting fossils in southern Borneo is a considerable challenge: most of the surface rocks are constantly eroded by heavy tropical rains, covered by dense vegetation, and in many cases, overshadowed by buildings or agricultural land. Despite these difficulties, in 2014, a team of researchers collected three large fossil seeds from the seams of a coal mine in South Kalimantan, Indonesian Borneo, the largest of which measured 7.2 cm in length, along with 43 leaves and two pollen samples. All the material was brought to the laboratory for detailed analysis.

To the great surprise of the researchers, the seeds found appear to be ancient relatives of the Castanospermum genus, of which today only one species exists worldwide. However, this lineage hides further surprises linked to tectonic movements. The collision between the tectonic plates of Southeast Asia and Australia, which began about 20 million years ago and is still ongoing, has led to a significant exchange of plant and animal species between these land masses. During the Cenozoic era, the area was affected by two major geological events: the Asia-India and Sahul-Sunda collisions. Sahul is part of the continental platform of the Australian continent and lies off the coasts of Australia, while Sunda is part of the Eurasian plate. The contact and collision between these regions allowed numerous plant lineages from Australia to migrate to Asia. This is evident from the fact that species found in the Asian fossil records are also present in the older Australian fossil records, suggesting that these plants initially evolved in Australia and later colonized Asia, providing a clear temporal signal of the migration.

But could the plants have made the reverse journey, from Asia to Australia? The rarity of plant macrofossils from Sunda has so far limited the understanding of pre-collision vegetation and the plants that migrated from Sunda to Sahul. Evidence in this regard was scarce and mainly based on palynological and molecular data. Until now. The discovery of this seed has provided the first macrofossil evidence of a plant evolutionary line that moved from Asia to Australia. Since Jantungspermum belongs to the same subfamily as Castanospermum, we can also hypothesize how the seeds may have dispersed. Today, Castanospermum disperses its seeds using floating, salt-tolerant pods that can travel for kilometers in rivers and oceans, especially after storm events. The fossil seeds of Jantungspermum were recovered from the upper Tambak Member (a member is a part of a geological formation distinguishable from the rest of the formation by its lithological characteristics) in a coastal depositional paleoenvironments, probably brackish, suggesting that their pods traveled a significant distance, similarly to its descendants, from the riparian parent plant before disintegrating and releasing their seeds.

The incredibility of this seed does not end here. These fossils also represent the oldest legume fossils in the Malay Archipelago. Moreover, the seeds are among the largest ever recorded in the fossil record, excluding coconuts and some other palms. They likely grew in a pod that reached the length of a baseball bat and could contain up to five seeds. The name Jantungspermum gunnellii derives from the Indonesian word "Jantung," which means heart, in reference to the shape of the fossil seed. "Spermum" means seed in Latin, while the specific term "gunnellii" is a tribute to the late Gregg Gunnell, a vertebrate paleontologist formerly at the Duke University Lemur Center, who led the expedition.

There are still many stories buried beneath the rock, and sometimes, a small yet big seed can reveal one of them.

source

[randomcollection-o-stuff]

I have stumbled upon the horrors and they stared back at me <<<man who googled “root fragment” expecting to see plant roots and instead was greeted by teeth, or rather, the lack thereof

[alphynix]

Trilobozoans (also known as triradialomorphs) are some of the more enigmatic members of the Ediacaran biota. In the past their unique three-way-symmetrical body plan was interpreted as linking them to groups like sponges, cnidarians, or echinoderms, but currently they're considered to be their own weird little phylum with uncertain evolutionary affinities, classified no more specifically than "probably some sort of early eumetazoan animal".

Lobodiscus tribrachialis is a newly-described member of this mysterious lineage. It lived in warm shallow marine waters covering what is now Southwestern China, and with an age of around 546 million years it's currently the youngest known trilobozoan, extending the group's time range by several million years.

About 3.7cm in diameter (~1.5"), it had the characteristic trilobozoan disc-shaped shield-like body, with a central depression surrounded by three triradially-symmetric lobes with branching ridges and grooves.

Its body would have been soft but fairly rigid, and it's not clear if it was capable of moving over the seafloor or if it had a more static lifestyle. Like its relative Tribrachidium it was probably a filter feeder, with the grooves on its surface directing water flow towards the central depression – and this surface ornamentation may also have been covered with cilia that actively caught and transported suspended food particles.

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NixIllustration.com | Tumblr | Patreon

References:

Ivantsov, A. Yu, and M. A. Zakrevskaya. "Trilobozoa, Precambrian tri-radial organisms." Paleontological Journal 55 (2021): 727-741. https://doi.org/10.1134/S0031030121070066

Ivantsov, Andrey, Aleksey Nagovitsyn, and Maria Zakrevskaya. "Traces of locomotion of Ediacaran macroorganisms." Geosciences 9.9 (2019): 395. https://doi.org/10.3390/geosciences9090395

Hall, C. M. S., et al. "The short-lived but successful tri-radial body plan: a view from the Ediacaran of Australia." Australian Journal of Earth Sciences 67.6 (2020): 885-895. https://doi.org/10.1080/08120099.2018.1472666

Rahman, Imran A., et al. "Suspension feeding in the enigmatic Ediacaran organism Tribrachidium demonstrates complexity of Neoproterozoic ecosystems." Science Advances 1.10 (2015): e1500800. https://doi.org/10.1126/sciadv.1500800

Zhao, Mingsheng, et al. "A putative triradial macrofossil from the Ediacaran Jiangchuan Biota." Iscience 27.2 (2024). https://doi.org/10.1016/j.isci.2024.108823

Wikipedia contributors. “Lobodiscus.” Wikipedia, 29 Mar. 2024, https://en.wikipedia.org/wiki/Lobodiscus

Wikipedia contributors. “Trilobozoa.” Wikipedia, 10 Mar. 2024, https://en.wikipedia.org/wiki/Trilobozoa

[headspace-hotel]

also. late quaternary extinction of a tree species in Eastern North America.

I've posted a little bit in the past about end-pleistocene megafauna extinctions, the overkill hypothesis, and the impact on "humans are the virus" type interpretations of ecology. This tree is the only documented end-Pleistocene plant extinction, which seems really striking, but this paper (from 1999) is like "yeah we haven't really studied it, and pollen deposits don't really allow for distinguishing plants on the species level, and most macrofossil sites have barely been analyzed."

I tried to do some research on end-pleistocene palynology in the USA and found this paper, which if anything gives a decent glimpse into what palynology does and doesn't allow us to analyze, and it is noted that "Nyssa, however, is distinctly entomophilous (Smiley Apiaries 2014), so just about any amount of its pollen in a sample suggests that the plants grew quite close to the site of deposition, where the discarded flowers accumulated. Because Nyssa is exclusively a freshwater entomophilous genus, the presence of its pollen in any significant quantity (>1%, F.J. Rich, personal observation) marks the site of a former freshwater wetland"

In other words, "Nyssa (blackgum) is insect pollinated, so its seriously weird that its pollen shows up in this fossil pollen sample, and would have to mean that there was a big grove of them with flowers falling to the ground right where the sample was collected."

Most of the species detected in this study are wind-pollinated species that are mega abundant and produce shit tons of airborne pollen, and they are identifiable down to either genus or family level. This means we can't say much about plants pollinated by insects, plants that were a small part of the total plants in the area, or plants that differed from modern ones only on species level.

Which means that it's misleading to say "there was only one End-Pleistocene plant extinction in USA" because we couldn't know that either way!

In fact the presence of plants like Torreya, Franklinia, and other "relict" plants along the Gulf Coast with ultra tiny ranges that likely used to be more widespread suggests that tons of plants could have gone extinct during the Last Glacial Maximum, since all it would take is a plant being 5% more intolerant to the glaciated climate than any of the numerous plants that got severely bottlenecked

It seems like the plants haven't gotten as much attention in research and that keeps being interpreted as "nah, there wasn't really an effect on the plants, only animals went extinct mostly" NO!!!!

[ashleysingermfablog]

Wk 16, 9th of May, 2024 Research

Findspot

findspot: the place where an archaeological object has been found or a place where an object is found.

From the text: A multi-proxy palaeoenvironmental investigation of the findspot of an Iron Age bog body from Oldcroghan, Co. Offaly, Ireland by Gill Plunkett...

In 2003, the remains of an Early Iron Age bog body, known as ‘Oldcroghan Man’, were recovered during the cutting of a drainage ditch in a bog in the Irish Midlands. Only some fingernails and a withe fragment remained undisturbed in situ in the drain face, providing the sole evidence for the original position of the body. A detailed reconstruction of the depositional context of the body has been undertaken through multi-proxy analyses of a peat monolith collected at the findspot. The palynological record shows that the surrounding area was the focus of intensive human activity during the Later Bronze Age, but was largely abandoned during the Bronze Age–Iron transition in the mid-first millennium BC. In the mid-4th century BC, a bog pool developed at the site, evidenced in the stratigraphic, plant macrofossil, testate amoebae and coleopteran records. Plant macrofossil and pollen analysis of peat samples associated with the fingernails suggests that the body was deposited in this pool most likely during the 3rd century BC. The absence of carrion beetle fauna points to complete submergence of the body within the pool. Deposition occurred shortly before or around the time that the surrounding area again became the focus of woodland clearance, as seen in the extended pollen record from the peat monolith. This period corresponds to the Early Iron Age in Ireland, during which renewed cultural connections with Britain and continental Europe can be seen in the archaeological record and widespread forest clearance is recorded in pollen records from across Ireland. The palaeoenvironmental results indicate, therefore, that the demise of Oldcroghan Man took place at a pivotal time of socio-economic and perhaps political change.

This paper describes the results of a multi-proxy palaeoenvironmental study conducted on a peat monolith collected from a section adjacent to the findspot of Oldcroghan Man. Using pollen, plant macrofossil, testate amoebae and coleopteran analyses, we reconstruct the landscape history of the surrounding area in the centuries bracketing the burial, as well as detailed local environmental conditions at the time the body was deposited in the bog.

From the text: THE FINDSPOTS OF BRONZE AGE METALWORK IN LOWLAND ENGLAND: A NEW FIELD STUDY by David Dunkin, David Yates and Richard Bradley...

This paper is concerned with the deposition of Middle and Late Bronze Age metalwork in three study areas extending from the coast of south-east England to the edge of the Fenland. It considers where hoards and single finds have been discovered and is based on inspection of over 300 findspots on the ground. It investigates regions in which tools and ornaments are common, but also extends to those with a stronger representation of weapons. While rapiers, swords and spears are found in rivers, terrestrial finds often come from sites close to springs, aquifers and confluences and favour areas with fresh water rather than salt water. Others are from more prominent locations on high ground or in low-lying positions like dry valleys. We suggest that such places played a role in a tiered cosmology. Metalwork was deposited where the underworld or the sky came into contact with the landscapes inhabited in daily life.

From the text: Staying local – experiencing local landscapes and the potential of hidden stories by Steven Timoney...

This article considers some of the opportunities increased visitation to recreational areas presents in terms of engaging residents and visitors with local heritage in the form of Historic Environment Records (HERs). There are countless potential ‘hidden stories’ related to cultural heritage sites and artefacts within palimpsest landscapes. These sites and artefacts present opportunities for alternative narratives of place to be negotiated, creating links to the past in the present, and between the exotic and the familiar. The changing approach to landscape practices resulting from COVID-19 restrictions presents new opportunities to engage people with these hidden stories, linking places near with far-off lands across time and space. It also encourages new connections with place that have the potential to (co-)create new narratives; increasing engagement, as well as correlating with pressing issues centred around the climate crisis and the urgent need to reduce travel to achieve Net Zero targets.

Taking Kinnoull Hill Woodland Park on the outskirts of the Scottish city of Perth as its focus, this article considers some of the opportunities this increased visitation presents in terms of engaging residents and visitors with local heritage. Within the landscape are countless potential ‘hidden stories’ related to cultural heritage sites and artefacts as part of palimpsest landscapes. These sites and artefacts present opportunities for alternative narratives of place to be negotiated, creating links to the past in the present, and between the exotic and the familiar. Heritage is often something that people travel to experience, and previously what was local may have been undesired or unknown (Lew Citation2018). Broadly speaking, outdoor recreation spaces saw an increase in activity resulting from varied COVID-19 lockdown measures (Bustad, Clevenger, and Rick Citation2023, 90). The restrictions on movement also provided the opportunity for explorations of ‘urban green spaces and the (re)formation of perspectives and practices attached to these’ (King and Dickinson Citation2023, 112). The changing approach to landscape practices resulting from COVID-19 restrictions presents new opportunities to engage people with these hidden stories, linking places near with far-off lands across time and space. It also encourages new connections with place that have the potential to (co-)create new narratives, increasing engagement; as well as correlating with pressing issues centred around the climate crisis and the urgent need to reduce travel to achieve Net Zero targets.

Chapter: Perceptions of landscape

The concept of landscape has evolved from its origins as landschap, used to refer to an area of land (Antrop Citation2013, 12), to what Wattchow describes as ‘a classic trans-disciplinary concept’ (Citation2013, 87). It is a complex construct that need to be interpreted, a reflection that social realities are constructed rather than innate (Atha et al. Citation2013, 2). As such, landscape does not just exist. Instead, landscape has been variously conceived as both a spatial and cultural entity (Brace and Geoghegan Citation2010, 287). They are texts to be read (Duncan and Duncan Citation1988); something that favours the visual, though the conscious and subconscious actions of individuals identify what is seen and how it is understood (Antrop and Van Eetvelde Citation2017, 62). It has been considered a dualism between its material reality and ideal representation (Timms Citation2008); landscape as a verb as well as a noun (Leyshon and Geoghegan Citation2012, 240). Though the separation of the cultural and the natural is not so clear cut:

As the familiar domain of our dwelling, [landscape] is with us, not against us, but it is no less real for that. And through living in it, the landscape becomes a part of us, just as we are a part of it (Ingold Citation 2000, 191).

Bound up within discussions of landscape are ideas around place, identity, and attachment. Aspects of identity then can have a geographical component. Place-identity refers to the way people use place as an influencing factor in the construction of identities (Proshansky, Fabian, and Kaminoff Citation1983). Tuan (Citation1974) saw space given meaning through the development of identities connected to landscape – what he defined as ‘topophilia’ (a love of place), with stronger attachments to place developing over time. Massey uses the term ‘a progressive sense of place’ (Massey Citation1994) to reflect the idea that the character of places is constructed by the flows of people and ‘things’ in and out of a space. Place attachment (Altman and Low Citation1992; Devine-Wright Citation2009) creates a sense of belonging with a spatial context in the sense of being in place.

Chapter: Perceptions of heritage

The purpose or role of heritage has been widely debated. Perceived distinctions between tangible remains and ‘objective’ history, have been compared to subjective, populist accounts which have been defined as heritage (Lowenthal Citation1998). The process of heritage is a selection of elements in the present that can be attributed to or provide connection with the past (Smith Citation2006; Tunbridge and Ashworth Citation1996). It has been argued, then, that these processes have facilitated a continued separation between archaeology and heritage in terms of management and practice, enabling archaeologists to be ‘very successful in protecting what they perceive to be their database’ (Smith and Waterton Citation2009, 1).

Bronze Age Gold from the Heyope hoard, The Museum of Wales online database in the archive Ancient Wales

Bronze Age Gold and tarnished metal from a findspot in Central Wales, The Museum of Wales online database in the archive Ancient Wales

[dipsiven]

First macrofossil record of Calophyllum in Thailand reported – The Lifestyle Insider

[scientificinquirer-blog]

Conversations with Pang Ke: Unraveling the Mysteries of Horodyskia And How Ancient Macrofossils Shed Light on Early Eukaryotic Evolution.

The enigmatic Proterozoic macrofossil genus Horodyskia, characterized by strings of bead-like structures, offers vital insights into early eukaryotic evolution. Despite its global distribution and fossil records extending from the early Mesoproterozoic Era (~1.48 Ga) to the terminal Ediacaran Period (~550 Ma), Horodyskia’s biological affinity is debated, with theories ranging from brown alga to…

[sciencespies]

Bacterial bloom as the Earth thawed: Photosynthetic organisms during the Snowball Earth

https://sciencespies.com/nature/bacterial-bloom-as-the-earth-thawed-photosynthetic-organisms-during-the-snowball-earth/

Bacterial bloom as the Earth thawed: Photosynthetic organisms during the Snowball Earth

Some researchers hypothesize that ice sheets enveloped the earth during the Marinoan glaciation (650-535 million years ago) in what is dubbed the “Snowball Earth.” The glaciation also impacted the climate and chemical compositions of the oceans, restraining the evolution of early life. Yet, as the earth warmed, and the Ediacaran period dawned, biotic life began to evolve.

A research team from Tohoku University has unveiled more about the evolutionary process of the Marinoan-Ediacaran transition. Using biomarker evidence, they revealed possible photosynthetic activity during the Marinoan glaciation. This was followed by photosynthetic organisms and bacteria entering a period of low productivity. However, as eukaryotes expanded during the early Ediacaran period, they blossomed.

Dr. Kunio Kaiho, who co-authored a paper with Atena Shizuya, said, “Our findings help clarify the evolution of primitive to complex animals in the aftermath of the Snowball Earth.” Their paper online was published in the journal Global and Planetary Change on August 8, 2021.

The late Neoproterozoic era (650-530 million years ago) witnessed one of the most severe ice ages in the Earth’s 4.6-billion-year history. Researchers believe that ice sheets covered the entire earth since glaciogenic units, such as ice-rafted debris, are distributed globally. Overlaying these glaciogenic formations are cap carbonates. These precipitate under warm conditions and therefore suggest that the glacial environment changed rapidly into a greenhouse environment.

The Snowball Earth hypothesis purports the atmospheric carbon dioxide concentration controlled the change from a frozen state to an ice-free state. Ice sheet-covered oceans prevented the dissolution of carbon dioxide into seawater during the Marinoan ice age, meaning greenhouse gas concentration, emitted by volcanic activity, increased gradually. Once the extreme greenhouse effect kicked in, glaciers melted and excess carbon dioxide precipitated on glaciogenic sediments as cap carbonates.

Whilst the Snowball Earth theory explains the wide distributions of glacial formations, it fails to shed light on the survival of living organisms. To counteract this, some researchers argue that sedimentary organic molecules, a molecular clock, and fossils from the late Neoproterozoic era are evidence that primitive eukaryotes such as sponges survived this severe ice age. Alternative models also propose that an ice-free open sea existed during the glaciation and acted as an oasis for marine life.

But what is understood is that the Marinoan glaciation and the succeeding extreme climatic transition likely had a marked impact on the biosphere. Shortly after the ice age, the Lantian biota, the earliest-known complex macroscopic multicellular eukaryotes, emerged. The Lantian biota includes macrofossils that are phylogenetically uncertain but morphologically and taxonomically diverse. Meanwhile, pre-Marinoan species have simple body plans with limited taxonomic variety.

Bacteria and eukaryote biomarkers demonstrate that bacteria dominated before the glaciation, whereas steranes/hopanes ratios illustrate that eukaryotes dominated just before it. However, the relationship between the biosphere changes and the Marinoan glaciation is unclear.

In 2011, Kaiho and his team traveled to Three Gorges, China under the guidance of China University of Science’s Dr. Jinnan Tong to take sedimentary rock samples from the deeper outcrops of marine sedimentary rocks. From 2015 onwards, Shizuya and Kaiho analyzed the biomarkers of algae, photosynthetic activity, bacteria, and eukaryotes from the rock samples.

They found photosynthetic activity based on n-C17 + n-C19 alkanes for algae and pristane + phytane during the Marinoan glaciation. Hopanes within the early and late carbonate deposition showed photosynthetic organisms and other bacteria entering a state of low productivity before recovering. And steranes from carbonates and mudstones after the cap carbonate deposition from the early Ediacaran period indicated the expansion of eukaryotes. The expansion of eukaryotes corresponded to the Lantian biota being morphologically diverse when compared to pre-Marinoan species.

Kaiho believes we are one step closer to understanding the evolutionary process that occurred before and after Snowball Earth. “The environmental stress of closed ocean environments for the atmosphere followed by high temperatures around 60°C may have produced more complex animals in the aftermath.” Their findings show that bacterial recovery preceded eukaryotes’ domination.

Kaiho’s team is doing further studies to clarify the relationship between climate change and the biosphere in other locations. They are also studying the relationship between atmospheric oxygen increases and animal evolution from the late Cryogenian to early Cambrian (650 to 500 million years ago).

Story Source:

Materials provided by Tohoku University. Note: Content may be edited for style and length.

#Nature

[fatehbaz]

A look at 7 species of maize (corn) being domesticated in different bioregions of Mesoamerica and the American Southwest before 2500 BC. Nice maps and timelines:

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A timeline of maize use at different sites extending back at least 9500 years:

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From:

Abstract: The first steps toward maize (Zea mays subspecies mays) domestication occurred in the Balsas region of Mexico by ∼9,000 calendar years B.P. (cal B.P.) [...]. Molecular and microbotanical data provide a partial picture of the timing and nature of morphological change, with genetic data indicating that alleles for some domestication traits were not yet fixed by 5,300 cal B.P. in the highlands of Mexico. Here, we report 88 radiocarbon dates on the botanical remains from El Gigante rockshelter (Honduras) to establish a Bayesian chronology over the past ∼11,000 y spanning the transition to maize-based food production. Botanical remains are remarkably well preserved and include over 10,000 maize macrofossils. We directly dated 37 maize cobs to establish the appearance and local change of maize at the site. Cobs are common in deposits dating between 4,340 and 4,020 cal B.P., and again between 2,350 and 980 cal B.P. [...] Our results indicate that domesticated landraces of maize productive enough to be a staple grain existed in Central America by 4,300 [years before present].

[forensicfield]

Rock and Forensic Science

👉 A rock may be defined simply as a mass of solid matter that is composed mainly of mineral crystals or grains that are texturally intergrown or held together by some form of cement.

👉 Pieces of rock have several attributes which can potentially be used as a basis for forensic comparison, including size, shape, surface texture (including weathering rinds and coatings), density, color, chemical composition, mineralogical composition, internal textural layering, fabric, magnetic characteristics, fossil assemblage (both macrofossil and microfossil), and age.

👉 Three main rock groups are: 🌑 Igneous, 🌑 Metamorphic, 🌑 and Sedimentary.

Each of which can be sub-divided, are traditionally distinguished.

[dropsofsciencenews]

Un Vecchio Fagiolo da Record

ESP version ENG version

Può un seme essere tra i più grandi mai registrati nel registro fossile, rappresentare la prima testimonianza di migrazione tra placche tettoniche verso la regione australiana ed essere anche l’unico antenato registrato del Castano Magnifico (Castanospermum australe)? La risposta è un triplice sì.

Di chi stiamo parlando? Il suo nome è Jantungspermum gunnellii, una pianta leguminosa che risale al periodo Eocene, in particolare a circa 34-40 milioni di anni fa.

La scoperta di questa pianta è stata frutto di estrema determinazione e, forse, anche di un po' di fortuna. Raccogliere fossili in Borneo meridionale è una sfida notevole: la maggior parte delle rocce in superficie è costantemente erosa dalle forti piogge tropicali, coperta da fitta vegetazione e, in molti casi, sovrastata da edifici o terreni agricoli. Nonostante queste difficoltà, nel 2014, un team di ricercatori ha raccolto dai filoni di una miniera di carbone nel Sud Kalimantan, Borneo indonesiano, tre grandi semi fossili, il più grande dei quali misurava 7,2 cm di lunghezza, oltre a 43 foglie e due campioni di polline. Tutto il materiale è stato portato in laboratorio per analisi dettagliate.

Con grande sorpresa dei ricercatori, i semi trovati sembrano essere antichi parenti del genere Castanospermum, di cui oggi esiste solo una specie al mondo. Tuttavia, questo lignaggio nasconde ulteriori sorprese legate ai movimenti tettonici. La collisione tra le placche tettoniche del sud-est asiatico e dell'Australia, iniziata circa 20 milioni di anni fa e ancora in corso, ha portato a un significativo scambio di specie vegetali e animali tra queste masse terrestri. Durante il Cenozoico, l'area è stata interessata da due importanti fenomeni geologici: le collisioni Asia-India e Sahul-Sonda. Sahul è parte della piattaforma continentale del continente australiano e giace al largo delle coste dell'Australia, mentre Sonda fa parte della placca euroasiatica. Il contatto e collisione tra queste zone ha permesso a numerose linee vegetali provenienti dall'Australia di migrare fino all’Asia. Questo è evidente dal fatto che le specie presenti nei record fossili asiatici si trovano anche nei più antichi record fossili australiani, suggerendo che queste piante si siano evolute inizialmente in Australia e successivamente abbiano colonizzato l'Asia, fornendo un chiaro segnale temporale della migrazione.

Ma le piante potrebbero aver compiuto anche il viaggio contrario, dall'Asia all'Australia? La rarità di macrofossili vegetali provenienti da Sonda ha finora limitato la comprensione della vegetazione pre-collisione e delle piante che migrarono da Sonda a Sahul.  Le prove a riguardo erano scarse e basate principalmente su dati palinologici e molecolari. Fino ad oggi. Aver scoperto questo seme ha fornito la prima evidenza macrofossile di una linea evolutiva vegetale che si è spostata dall'Asia all'Australia. Dato che Jantungspermum appartiene alla stessa sottofamiglia del Castanospermum, possiamo ipotizzare anche come i semi si siano spostati. Oggi, Castanospermum disperde i suoi semi utilizzando baccelli galleggianti e tolleranti al sale, capaci di viaggiare per chilometri in fiumi e oceani, specialmente dopo eventi tempestosi. I semi fossili di Jantungspermum sono stati recuperati dal Membro superiore di Tambak (un membro è una parte di una formazione geologica distinguibile dal resto della formazione stessa in base alle sue caratteristiche litologiche) in un paleombiente deposizionale costiero, probabilmente salmastro, suggerendo che i loro baccelli abbiano viaggiato una distanza significativa, analogamente ai suoi discendenti, dalla pianta genitrice ripariale prima di disintegrarsi e rilasciare i loro semi.

L’incredibilità di questo seme non finisce qui. Questi fossili rappresentano anche i legumi fossili più antichi dell'arcipelago malese. Inoltre, i semi sono tra i più grandi mai registrati nei fossili, esclusi quelli di noci di cocco e alcune altre palme. Crescevano probabilmente in un baccello che raggiungeva la lunghezza di una mazza da baseball e poteva contenere fino a cinque semi.

Il nome Jantungspermum gunnellii deriva dalla parola indonesiana "Jantung", che significa cuore, in riferimento alla forma del seme fossile. "Spermum" significa seme in latino, mentre il termine specifico "gunnellii" è un omaggio al defunto Gregg Gunnell, un paleontologo di vertebrati precedentemente al Duke University Lemur Center, che ha guidato la spedizione.

Ci sono ancora molte storie sepolte sotto la roccia e, a volte, un piccolo grande seme può svelarcene una.

fonte

[icartant]

Hand chiseled/carved limestone plaque of a lion tearing flesh. "A" under the lion's torso, possibly a "C" formed by a portionnof the lion's tail. "NCANTAM" below the lion's feet. Latin?? The style of the lion's mane and head are not modern. The age of this is unclear. Limestone measures 12" square and 1" thick. Chisel marks and macrofossils are clearly visible on the polished surface. #limestoneplaque #lionplaque #carvedstone #unknownage @iowacityart (at Iowa City Art & Antiques) https://www.instagram.com/p/CUGomfho1_T/?utm_medium=tumblr

[evoldir]

Fwd: Postdoc: UppsalaU.PhylogenomicsAndMolecularClock

Begin forwarded message: > From: evoldir@evol.biology.mcmaster.ca > Subject: Postdoc: UppsalaU.PhylogenomicsAndMolecularClock > Date: 25 February 2016 at 07:48:37 GMT > To: rdmpage@gmail.com > > > Postdoc/Researcherin Systematic Biology > > UppsalaUniversity is an international research university focused on the > development of science and education. Our most important assets are all > the individuals who with their curiosity and their dedication make Uppsala > University one of Swedenขs most exciting work places. Uppsala University > has 40,000 students, 7,000 employees and a turnover of SEK 6,5 billion. > > Description:Resolving the global tree of life has long been a main > goal of Biology. In recent years, breakthroughs in high-throughput > sequencing and faster phylogenetic algorithms have allowed to refine > the structure of the tree in unprecedented ways. For eukaryotes, all > major groups as well as many once enigmatic lineages now have genomic > data available. This wealth of data has opened the door to study the > deep relationships among eukaryotes with more confidence, and map onto > the tree some of the main evolutionary events. Here, we propose to > go further by combining phylogenetics, genomics (i.e. phylogenomics), > and molecular dating to address long-standing questions in eukaryote > evolution, such as the origin and spread of plastids. For this purpose, > we will infer a genomic timescale calibrated with the microfossil record > of protists, which presents the key benefit of being continuous and > thus more comprehensive than macrofossils. This is a timely project at > the forefront of microbial genomics and evolution, within a motivating > scientific environment that will lead to some exciting developments in > understanding the diversity of eukaryotes. > > Qualifications:Depending on seniority, this position will be filled > either as postdoctoral fellow or researcher. Eligible for employment as > postdoctoral fellow are those who have a doctoral degree or a foreign > degree found to be equivalent with a doctoral degree, obtained within > three years before the deadline for applications. If there are special > reasons, the degree may be older than three years. Special reasons > refer to absence due to illness, parental leave, commissions of trust > within trade unions or other similar circumstances. Eligible for > employment as researcher are those with a doctoral degree older than > three years. Candidates must be fluent in English with strong writing > skills. This position is for 2 years. > > Assessment:I am looking for a highly motivated individual with > strong academic proficiency within the field of (microbial) eukaryote > evolution. Proven experience in bioinformatics to handle genomic-scale > datasets, phylogenetics, and molecular dating will be highly > valued. Documented skills in phylogenomics would be an asset. > > Application:The application should include a letter in which the applicant > describes oneself and the research interests (one A4 page) and contact > information for three references. The application should also include > CV and a copy of the doctoral degree. Personal circumstances (such as > parental leave) that the assessment of qualifications may be credited > to the applicant, should be indicated in the list of qualifications > and experience. > > UppsalaUniversity is striving to promote gender equality through gender > balance. The majority of employees in this category are women, which is > why we would like to see men as candidates for the position. > > Informationabout the position will be given by Fabien Burki: > fabien.burki@ebc.uu.se(from March 1st) or burkif@mail.ubc.ca > > Moreinformation can also be found here: > https://ift.tt/3jXq5jG > > > > fabien.burki@botany.ubc.ca > via IFTTT

[dipsiven]

First macrofossil record of Calophyllum in Thailand reported – The Lifestyle Insider

[naomiyuan]

In ‘Moon Landing of Genomics,’ Scientists Sequence Ancient DNA From Dirt

Scientists have pieced together multiple entire ancient bear genetic codes from soil sediment.

The secret is using whole genomes as templates to reconstruct the ancient DNA.

Scientists now have a whole floodgate of new genetics to open up.

Scientists have achieved a breakthrough they’re comparing to the moon landing: sequencing a full ancient genome from soil samples.

How’s that on par with humans touching down on the lunar surface? Well, the research team from the University of Copenhagen found the entire genetic code of an ancient bear species without obtaining it from fossils, marking the very first time scientists have found genes outside the fossil record. And by gathering the DNA from the soil, these researchers gathered a bunch of examples, rather than just one single specimen’s genome.

The scientists found the ancient bear genetic material in the soil of Chiquihuite Cave in rural Mexico. Like the ancient Chauvet Cave in France, Chiquihuite contains some of the oldest human evidence in the world—but humans weren’t the only ones to use the caves.

The ancestral bear DNA dates back to about 16,000 years ago, and it comes from an unsavory, but logical source: bear waste.

“When an animal or a human urinates or defecates, cells from the organism are also excreted,” geneticist Eske Willerslev told ScienceAlert. “We have shown that hair, urine, and feces all provide genetic material which, in the right conditions, can survive for much longer than 10,000 years.”

From there, the researchers assembled the pieces of environmental DNA (eDNA). “Standard eDNA techniques allow species to be determined [without] macrofossils across a variety of environments including sediments, ice cores, lakes, rivers, and oceans,” the scientists explain in their paper, which appears in Current Biology.

Printing in China

So how did the team assemble the bears’ genome from these environmental scraps?

“We estimated a mitochondrial phylogeny using whole mitogenomes of the eight extant bears of the family Ursidae as well as three extinct bear lineages: cave bears (U. spelaeus) and the two extinct tremarctine bears, the North American giant short-faced bear, Arctodus, and the South American giant short-faced bear, Arctotherium, which we reassembled using the Andean bear as reference.”

Basically, the scientists patched together the complete ancient genome using modern and extinct bears as templates—think about using a model of a bottlenose dolphin as a guide to assemble the body parts of a killer whale. The parts aren’t exactly alike, but both animals have a dorsal fin and a blowhole.

Fossils offer scientists a huge amount of information, but the fossil record is spotty by nature, and doesn’t make sense to rely on as something to fully inform us about everyday activities and whole populations of animals. For example, one full T. rex specimen, while spectacular, doesn’t explain what the whole species’ genetic information was like.

Willerslev told ScienceAlert this research is “the moon landing of genomics” because it allows study of the genome without any fossil findings—bringing with it a vast wealth of new genetic information that can be gleaned fully from soil and other sediment.

[sciencespies]

Scientists in Japan just found a Detailed Record of Earth's Last Magnetic Switcharoo

https://sciencespies.com/space/scientists-in-japan-just-found-a-detailed-record-of-earths-last-magnetic-switcharoo/

Scientists in Japan just found a Detailed Record of Earth's Last Magnetic Switcharoo

Every 200,000 to 300,000 years, Earth’s magnetic poles reverse. What was once the north pole becomes the south, and vice versa. It’s a time of invisible upheaval.

The last reversal was unusual because it was so long ago. For some reason, the poles have remained oriented the way they are now for about three-quarters of a million years. A new study has revealed some of the detail of that reversal.

The study of the Earth’s magnetic field is called paleomagnetism. It involves the study of rocks and sediments and sometimes archaeological materials. Rocks that were once molten retain a record of the Earth’s magnetic field as they solidified.

The related field of magnetostratigraphy studies the record of geomagnetic reversals that are contained in those rocks. By dating the rocks, researchers can construct a timeline of the Earth’s reversals.

The last reversal is named the Matuyama-Brunhes geomagnetic reversal after the co-discoverers: Bernard Brunhes, a French geophysicist, and Motonori Matuyama, a Japanese geophysicist. Over the years since its discovery, researchers have tried to understand exactly when it happened, and also how long it took.

This new study is titled “A full sequence of the Matuyama–Brunhes geomagnetic reversal in the Chiba composite section, Central Japan.” The lead author is Yuki Haneda, a project researcher at the National Institute of Polar Research and a postdoctoral research fellow at the National Institute of Advanced Industrial Science and Technology in Japan.

The paper is published in the journal Progress in Earth and Planetary Science.

Lava flows are a reliable indicator of the orientation of Earth’s magnetic poles at the time the lava solidified. But what they can’t provide is a timeline. They’re more like snapshots that freeze a moment in time.

Lava flows are very helpful when it comes to understanding the Earth’s magnetic field at the time of solidification. “However, lava sequences cannot provide continuous paleomagnetic records due to the nature of sporadic eruptions,” lead author Haneda said in a press release.

A better record can be found in some sediment deposits, which can form over a long period of time. One of these deposits is called the Chiba composite section. It’s in Japan, and geophysicists consider it to be a very detailed record of the Matuyama-Brunhes reversal.

“In this study, we collected new samples and conducted paleo- and rock-magnetic analyses of samples from the Chiba composite section, a continuous and expanded marine succession in Central Japan, to reconstruct the full sequence of the Matuyama-Brunhes geomagnetic reversal,” Haneda said.

The Chiba composite section is widely considered to contain the most detailed marine sedimentary record of the Matuyama-Brunhes geomagnetic reversal, according to Haneda.

It serves as the international standard for the lower boundary of the Middle Pleistocene Subseries and Chibanian Stage — when Homo sapiens emerged as a species.

The Chiba composite section is notable for its well-preserved pollen and marine micro- and macrofossils. It also contains tephra beds. Tephra is a fragmentary material produced by volcanic eruptions, normally referred to as volcanic ash.

All in all, Chiba provides the most reliable chronostratigraphic framework of the time period around the Brunhes-Matuyama reversal.

What they found goes against what some other studies have uncovered, especially when it comes to how long the reversal took to occur. Some studies suggest it took several thousand years, while another suggested that the reversal was completed in one human lifetime.

The different time estimates depend largely on where on Earth researchers gather their evidence. This study based on the Chiba composite section says it took about 20,000 years, including a 10,000 year period of instability leading up to the reversal.

“Our data is one of the most detailed paleomagnetic record during the Matuyama-Brunhes geomagnetic reversal, offering deep insight into the mechanism of the geomagnetic reversal,” Haneda said.

The marine micro-fossils and pollen found in the Chiba composite section also hold clues to the magnetic reversal. The team of researchers is going to investigate fossils and pollen next to try to learn more.

This figure from the study shows the location of the study area on Japan’s Boso Peninsula. (Haneda et al., 2020)

The question that looms over Earth’s geomagnetic reversals is ‘What effect do they have?’ That’s outside the scope of this study, but it’s the focus of other research. 

Some researchers have wondered if magnetic reversals have contributed to climate change. While the evidence is nowhere near complete, some scientists have outlined how reversals might play a role.

In 2006 a team of researchers made a presentation to the American Geophysical Union’s Fall Meeting titled “Does the Earth’s Magnetic Field Influence Climate?“

When mentioning the accepted causes of climate change on Earth, the team said, “Magnetism has seldom been invoked, and evidence for connections between climate and magnetic field variations have received little attention.”

“The most intriguing feature may be recently proposed archaeomagnetic jerks. These seem to correlate with significant climatic events.”

Archaeomagnetic jerks are quick changes in the Earth’s geomagnetic field that are localized rather than global. While there’s only a correlation between them and climate, a causal link might one day be established. Could there also be a causal link between magnetic reversals and climate?

The effect that magnetic reversals have on animals is likewise a fascinating and open question. Many animals undertake long, migratory voyages. Whales, birds, and sea turtles, for example.

And there’s evidence that some migratory species rely on Earth’s magnetic field to navigate. The phenomenon is called magnetoreception.

How are creatures that rely on magnetoreception affected by geomagnetic reversals?

During a reversal, the magnetic poles not only switch places but the field strength drops. There may also be temporary poles at the equator or even multiple temporary poles. The poles can also wander around, leaving their original position and returning before eventually switching completely.

It’s not clear what effect a reversal has on animals. But there’s some evidence that solar storms, with all their magnetic activity, can create confusion for migrating whales and may even drive them to beach themselves.

During a reversal, the protective effect of the Earth’s magnetic field is reduced. More solar radiation may reach the surface of Earth during a reversal, which could put animals like whales in peril the same way a solar storm might. However, the evidence for this is not clear.

In any case, life on Earth has survived many geomagnetic reversals, and still, life thrives. Modern humans haven’t faced one yet, so observing the next one will be very instructive. 

The most likely effect will be on our power and communications systems, including satellites. As the global magnetic field weakens, more of the Sun’s radiation can get through. We know from things like the Carrington Event that that scenario can be very damaging. 

While this study can’t address all these questions, it does advance our understanding of the previous reversal. 

“Our results provide a detailed and expanded sedimentary record of the M–B geomagnetic reversal and offer valuable new information to further understand the mechanisms and dynamics of geomagnetic reversals,” the authors conclude.

This article was originally published by Universe Today. Read the original article.

#Space