Burmese amber#Vertebrates

File:Burmese amber geological context PNAS Fig1 A (cropped).jpg

The amber is found in the Hukawng Basin, a large Cretaceous-Cenozoic sedimentary basin within northern Myanmar. The strata have undergone folding and faulting. The Hukawng basin is part of the larger Myanmar Central Basin, a N-S orientated synclinal basin extending to the Gulf of Martaban to the south. The basin is considered to be a part of the West Burma block (a.k.a. Burma terrane), which has a debated tectonic history, it is considered to be associated with the concepts of the Cimmeria and Sibumasu terranes. The block was part of Gondwana during at least the Early Paleozoic, but the timing of rifting is very uncertain, with estimates ranging from the Devonian to Early Cretaceous. It is also disputed whether the block had accreted onto the Asian continental margin by the time of the amber deposition.{{Cite journal|last=Metcalfe|first=Ian|date=June 2017|title=Tectonic evolution of Sundaland|journal=Bulletin of the Geological Society of Malaysia|volume=63|pages=27–60|doi=10.7186/bgsm63201702|doi-access=free}} Some members of the flora and fauna have Gondwanan affinities,{{Cite journal|last=Poinar|first=George|date=2018-03-09|title=Burmese amber: evidence of Gondwanan origin and Cretaceous dispersion|journal=Historical Biology|language=en|pages=1–6|doi=10.1080/08912963.2018.1446531|s2cid=90373037|issn=0891-2963}} while others have Laurasian affinities.{{Cite journal |last=Hinkelman |first=Jan |date=2022-01-10 |title=Mongolblatta sendii sp. n. (Mesoblattinidae) from North Myanmar amber links record to Laurasian sediments |url=http://www.schweizerbart.de/papers/pala/detail/321/100594/Mongolblatta_sendii_sp_n_Mesoblattinidae_from_Nort?af=crossref |journal=Palaeontographica Abteilung A |language=en |volume=321 |issue=1–6 |pages=81–96 |doi=10.1127/pala/2021/0105 |bibcode=2022PalAA.321...81H |s2cid=240162578 |issn=0375-0442}} A recent paleomagnetic reconstruction finds that the Burma terrane formed an island land mass in the Tethys Ocean during the Mid Cretaceous at a latitude around 5-10 degrees south of the equator.{{Cite journal|last1=Westerweel|first1=Jan|last2=Roperch|first2=Pierrick|last3=Licht|first3=Alexis|last4=Dupont-Nivet|first4=G.|last5=Win|first5=Zaw|last6=Poblete|first6=Fernando|last7=Ruffet|first7=Gilles|last8=Swe|first8=Hnin|last9=Thi|first9=Myat|last10=Aung|first10=Day|date=2019-10-01|title=Burma Terrane part of the Trans-Tethyan Arc during collision with India according to palaeomagnetic data|journal=Nature Geoscience|volume=12|issue=10|pages=863–868|doi=10.1038/s41561-019-0443-2|pmid=31579400|pmc=6774779|bibcode=2019NatGe..12..863W}}

At Noije Bum, located on a ridge, amber is found within fine grained clastic rocks, typically medium to greyish green in colour, resulting from the constituent grains being black, yellow, grey and light green. The fine grained rocks are primarily fine to very fine grained sandstone, with beds of silt and shale and laterally persistent thin (1–2 mm thick) coal horizons. Massive micritic limestone interbeds of 6-8 centimetre thickness, often containing coalified plant material also occur. This facies association is typically around 1 metre thick and typically thinly bedded and laminated. Associated with the fine grained facies is a set of medium facies primarily consisting of medium to fine grained sandstones also containing thin beds of siltstone, shale and conglomerate, alongside a persistent conglomerate horizon. A specimen of the ammonite Mortoniceras has been found in a sandstone bed 2 metres above the amber horizon, alongside indeterminate gastropods and bivalves.{{Cite journal|last1=Cruickshank|first1=R.D|last2=Ko|first2=Ko|date=February 2003|title=Geology of an amber locality in the Hukawng Valley, Northern Myanmar|journal=Journal of Asian Earth Sciences|language=en|volume=21|issue=5|pages=441–455|doi=10.1016/S1367-9120(02)00044-5|bibcode=2003JAESc..21..441C}} Lead-uranium dating of zircon crystals of volcanic clasts within the amber bearing horizons has given a maximum age of 98.79 ± 0.62  million years ago (Ma), making the deposit earliest Cenomanian in age.{{Cite journal|last1=Shi|first1=Guanghai|last2=Grimaldi|first2=David A.|last3=Harlow|first3=George E.|last4=Wang|first4=Jing|last5=Wang|first5=Jun|last6=Yang|first6=Mengchu|last7=Lei|first7=Weiyan|last8=Li|first8=Qiuli|last9=Li|first9=Xianhua|date=October 2012|title=Age constraint on Burmese amber based on U–Pb dating of zircons|journal=Cretaceous Research |language=en|volume=37|pages=155–163|doi=10.1016/j.cretres.2012.03.014|bibcode=2012CrRes..37..155S }} Unpublished data by Wang Bo on other layers suggests an age range of deposition of at least 5 million years. The amber does not appear to have undergone significant transport since hardening or be redeposited. The strata at the site are younging upwards, striking north north-east and dipping 50-70 degrees E and SE north of the ridge and striking between south south-east and south-east and dipping 35-60 degrees south-west south of the ridge, suggesting the site is on the northwest limb of a syncline plunging to the northeast. A minor fault with a conspicuous gouge zone was noted as present, though it appeared to have no significant displacement. Several other localities are known, including the colonial Khanjamaw and the more recent Inzutzut, Angbamo, and Xipiugong sites, within the vicinity of Tanai. The Hkamti site SW of the Hukawng basin has been determined to be significantly older, dating to the early Albian around ca. 110 Ma and is therefore considered distinct.{{Cite journal|last1=Xing|first1=Lida|last2=Qiu|first2=Liang|date=November 2020|title=Zircon U Pb age constraints on the mid-Cretaceous Hkamti amber biota in northern Myanmar|url=https://linkinghub.elsevier.com/retrieve/pii/S0031018220304053|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|language=en|volume=558|pages=109960|doi=10.1016/j.palaeo.2020.109960|bibcode=2020PPP...55809960X|s2cid=224899464}}

File:Puzosia Bhimaites species Burmese amber PNAS Fig2 A.jpg (Bhimaites) species juvenile shell in Burmese amber]]

The Burmese amber paleoforest is considered to have been a tropical rainforest, situated near the coast, where resin was subsequently transported into a shallow marine environment. The shell of a dead juvenile Puzosia (Bhimaites) ammonite, four marine gastropod shells (including Mathilda) and littoral or supralittoral isopods entombed in a piece of amber with shell sand,{{cite journal|last1=Yu |first1=T. |last2=Kelly |first2=R. |last3=Mu |first3=L |last4=Ross |first4=A. |last5=Kennedy |first5=J. |last6=Broly |first6=P. |last7=Xia |first7=F. |last8=Zhang |first8=H. |last9=Wang |first9=B. |last10=Dilcher |first10=D. |date=2019-06-04 |title=An ammonite trapped in Burmese amber |journal=Proceedings of the National Academy of Sciences |language=en |volume=116 |issue=23 |pages=11345–11350 |doi=10.1073/pnas.1821292116 |issn=0027-8424 |pmc=6561253 |pmid=31085633|bibcode=2019PNAS..11611345Y |doi-access=free }} along with growth of Isocrinid crinoids, corals and oysters on the surface of some amber pieces indicate marine conditions for final deposition.{{Cite journal |last1=Mao |first1=Y. |last2=Liang |first2=K. |last3=Su |first3=Y. |last4=Li |first4=J. |last5=Rao |first5=X. |last6=Zhang |first6=H. |last7=Xia |first7=F. |last8=Fu |first8=Y. |last9=Cai |first9=C. |last10=Huang |first10=D. |date=2018-12-28 |title=Various amberground marine animals on Burmese amber with discussions on its age |journal=Palaeoentomology |volume=1 |issue=1 |pages=91 |doi=10.11646/palaeoentomology.1.1.11|s2cid=68048811 |issn=2624-2834}} Additionally pholadid (piddock) bivalve borings into amber specimens along with at least one pholadid which became trapped was interpreted to show that the resin was still fresh and unhardened when it was being moved into the tidal areas.{{Cite journal|last1=Smith |first1=Ru D. A. |last2=Ross |first2=Andrew J. |date=January 2018 |title=Amberground pholadid bivalve borings and inclusions in Burmese amber: implications for proximity of resin-producing forests to brackish waters, and the age of the amber |journal=Earth and Environmental Science Transactions of the Royal Society of Edinburgh |language=en |volume=107 |issue=2–3 |pages=239–247 |doi=10.1017/S1755691017000287|s2cid=204250232 |issn=1755-6910}} However, the phloladids in question, belonging to the extinct genus Palaeolignopholas, were later interpreted as a freshwater species, and the presence of numerous freshwater insects suggests that the initial environment of deposition was a downstream estuarine to freshwater section of a river, with the forests extending across coastal rivers, river deltas, lakes, lagoons, and coastal bays.{{Cite journal|last1=Bolotov|first1=Ivan N.|last2=Aksenova|first2=Olga V.|last3=Vikhrev|first3=Ilya V.|last4=Konopleva|first4=Ekaterina S.|last5=Chapurina|first5=Yulia E.|last6=Kondakov|first6=Alexander V.|date=2021-03-23|title=A new fossil piddock (Bivalvia: Pholadidae) may indicate estuarine to freshwater environments near Cretaceous amber-producing forests in Myanmar|journal=Scientific Reports|language=en|volume=11|issue=1|pages=6646|doi=10.1038/s41598-021-86241-y|pmid=33758318|pmc=7988128|bibcode=2021NatSR..11.6646B|issn=2045-2322|doi-access=free}} The forest environment may have been prone to fire, similar to modern tropical peat swamps, based on the presence of fire adapted plants and burned plant remains found in the amber.{{Cite journal |last1=Shi |first1=Chao |last2=Wang |first2=Shuo |last3=Cai |first3=Hao-hong |last4=Zhang |first4=Hong-rui |last5=Long |first5=Xiao-xuan |last6=Tihelka |first6=Erik |last7=Song |first7=Wei-cai |last8=Feng |first8=Qi |last9=Jiang |first9=Ri-xin |last10=Cai |first10=Chen-yang |last11=Lombard |first11=Natasha |last12=Li |first12=Xiong |last13=Yuan |first13=Ji |last14=Zhu |first14=Jian-ping |last15=Yang |first15=Hui-yu |date=February 2022 |title=Fire-prone Rhamnaceae with South African affinities in Cretaceous Myanmar amber |url=https://www.nature.com/articles/s41477-021-01091-w |journal=Nature Plants |language=en |volume=8 |issue=2 |pages=125–135 |doi=10.1038/s41477-021-01091-w |pmid=35102275 |bibcode=2022NatPl...8..125S |s2cid=246443363 |issn=2055-0278}}

The amber itself is primarily disc-shaped and flattened along the bedding plane, and is typically reddish brown, with the colour ranging from shades of yellow to red. The opacity of the amber ranges from clear to opaque. Many amber pieces have thin calcite veins that are typically less than {{convert|1|mm|in|2|abbr=on}}, but up to {{convert|4-5|mm|in|abbr=on}} thick. The number and proportion of veins in a piece of amber varies significantly, in some pieces veins are virtually absent, while others are described as being "packed with veinlets". The amber is considered to be of coniferous origin, with a likely araucarian source tree, based on spectroscopic analysis and wood fragment inclusions,{{Cite journal |last1=Poinar |first1=G. |last2=Lambert |first2=J.B. |last3=Wu |first3=Y. |date=2007-08-10|title=Araucarian source of fossiliferous Burmese amber: Spectroscopic and anatomical evidence |url=https://www.researchgate.net/publication/285888390 |journal=Journal of the Botanical Research Institute of Texas |volume=1 |pages=449–455}} though a pine origin has also been suggested.{{Cite journal|last1=Dutta |first1=S. |last2=Mallick |first2=M. |last3=Kumar |first3=K. |last4=Mann |first4=U. |last5=Greenwood |first5=P. F. |date=January 2011 |title=Terpenoid composition and botanical affinity of Cretaceous resins from India and Myanmar |journal=International Journal of Coal Geology |language=en |volume=85 |issue=1 |pages=49–55 |doi=10.1016/j.coal.2010.09.006|bibcode=2011IJCG...85...49D }}

{{Main|Paleobiota of Burmese amber}}

The list of taxa is extraordinarily diverse, with 50 classes (or equivalent), 133 orders (or equivalent), 726 families, 1,757 genera and 2,770 species described as of 2023. The vast majority of the species are arthropods, mostly insects.{{Cite journal |last=Ross |first=Andrew J. |date=2024-03-28 |title=Complete checklist of Burmese (Myanmar) amber taxa 2023 |url=https://mapress.com/mz/article/view/mesozoic.1.1.4 |journal=Mesozoic |volume=1 |issue=1 |pages=21–57 |doi=10.11646/mesozoic.1.1.4 |issn=3021-1867|doi-access=free }}

{{Further|Insect paleobiota of Burmese amber}}File:M466395.jpg in Burmese amber]]

Over 2500 species of arthropods (with over 2000 of these species beings insects) are known from the deposit, notably including the oldest members of the arachnid orders Palpigradi (Electrokoenenia){{cite journal|last1=Engel|first1=Michael S.|last2=Breitkreuz|first2=Laura C. V.|last3=Cai|first3=Chenyang|last4=Alvarado|first4=Mabel|last5=Azar|first5=Dany|last6=Huang|first6=Diying|date=15 February 2016|title=The first Mesozoic microwhip scorpion (Palpigradi): a new genus and species in mid-Cretaceous amber from Myanmar|journal=The Science of Nature|volume=103|issue=3–4|pages=19|doi=10.1007/s00114-016-1345-4|pmid=26879963|bibcode=2016SciNa.103...19E|s2cid=14816297}} and Schizomida{{Cite journal|last1=Müller|first1=Sandro P.|last2=Dunlop|first2=Jason A.|last3=Kotthoff|first3=Ulrich|last4=Hammel|first4=Jörg U.|last5=Harms|first5=Danilo|date=February 2020|title=The oldest short-tailed whipscorpion (Schizomida): A new genus and species from the Upper Cretaceous amber of northern Myanmar|journal=Cretaceous Research|language=en|volume=106|pages=104227|doi=10.1016/j.cretres.2019.104227|bibcode=2020CrRes.10604227M |s2cid=202899476}} and the only known fossil members of Ricinulei since the Paleozoic.{{Cite journal |last1=Botero-Trujillo |first1=Ricardo |last2=Davis |first2=Steven R. |last3=Michalik |first3=Peter |last4=Prendini |first4=Lorenzo |date=2022-09-22 |title=Hirsutisoma grimaldii sp. nov., a ca. 99-million-year-old ricinuleid (Primoricinulei, Hirsutisomidae) from Cretaceous Burmese amber with a corticolous, scansorial lifestyle |url=https://mapress.com/pe/article/view/palaeoentomology.5.5.11 |journal=Palaeoentomology |volume=5 |issue=5 |doi=10.11646/palaeoentomology.5.5.11 |issn=2624-2834}} Chimerarachne is a unique stem-group spider still possessing a tail, with similar forms only known from the Paleozoic,{{Cite journal |last=Dunlop |first=Jason A. |date=2022-06-27 |title=Spider Origins: a Palaeontological Perspective |url=https://bioone.org/journals/arachnology/volume-19/issue-sp1/arac.2022.19.sp1.182/Spider-Origins-a-Palaeontological-Perspective/10.13156/arac.2022.19.sp1.182.full |journal=Arachnology |volume=19 |issue=sp1 |doi=10.13156/arac.2022.19.sp1.182 |issn=2050-9928 |s2cid=250148030}} with over 360 other species of spiders (including the only non Paleozoic fossils of Mesothelae) being known from Burmese amber, along with over 40 species of scorpions. Other significant arachnid fossils include some of the oldest ticks,{{Cite journal |last1=Chitimia-Dobler |first1=Lidia |last2=Mans |first2=Ben J. |last3=Handschuh |first3=Stephan |last4=Dunlop |first4=Jason A. |year=2022 |title=A remarkable assemblage of ticks from mid-Cretaceous Burmese amber |journal=Parasitology |language=en |volume=149 |issue=6 |pages=820–830 |doi=10.1017/S0031182022000269 |issn=0031-1820 |pmc=10090602 |pmid=35241194 |s2cid=247227499 |doi-access=free}} as well as the oldest mesostigmatan{{Cite journal |last1=Joharchi |first1=Omid |last2=Vorontsov |first2=Dmitry D. |last3=Walter |first3=David Evans |date=2021-09-14 |title=Oldest determined record of a mesostigmatic mite (Acari: Mesostigmata: Sejidae) in Cretaceous Burmese amber |journal=Acarologia |volume=61 |issue=3 |pages=641–649 |doi=10.24349/goj5-bzms |issn=0044-586X |s2cid=239420481 |doi-access=free}} and opilioacarid mites.{{cite journal |author=Jason A. Dunlop |author2=Leopoldo Ferreira de Oliveira Bernardi |name-list-style=amp |year=2014 |title=An opilioacarid mite in Cretaceous Burmese amber |journal=Naturwissenschaften |volume=101 |issue=9 |pages=759–763 |doi=10.1007/s00114-014-1212-0 |pmid=25027588 |bibcode=2014NW....101..759D |s2cid=253637881}} Beetles (Coleoptera), reflecting their modern diversity, are represented by over 100 families and over 500 species, with Hymenoptera (bees, wasps, ants and sawflies) represented by 70 families and 350 species including some of the oldest known ants. Flies (Diptera) are represented by over 50 families and over 250 species and true bugs (Hemiptera) are represented by over 80 families and over 220 species. Dictyoptera (cockroaches, termites and mantises, among others), are represented by over 100 species in 28 families. Odonata (which contains dragonflies and damselflies, among other extinct groups), is represented by over 19 families and over 40 species, far higher than in other Cretaceous amber deposits.{{Cite journal |last1=Zheng |first1=Daran |last2=Jarzembowski |first2=Edmund A. |date=2020-01-02 |title=A brief review of Odonata in mid-Cretaceous Burmese amber |url=https://worlddragonfly.org/article/13887890-2019-1688499/ |journal=International Journal of Odonatology |language=en |volume=23 |issue=1 |pages=13–21 |doi=10.1080/13887890.2019.1688499 |bibcode=2020IJOdo..23...13Z |issn=1388-7890|doi-access=free }} Among the oldest members of the insect order Zoraptera are known from Burmese amber,{{Cite journal |last1=Yin |first1=Ziwei |last2=Cai |first2=Chenyang |last3=Huang |first3=Diying |date=April 2018 |title=New zorapterans (Zoraptera) from Burmese amber suggest higher paleodiversity of the order in tropical forests |journal=Cretaceous Research |language=en |volume=84 |pages=168–172 |doi=10.1016/j.cretres.2017.11.028|doi-access=free |bibcode=2018CrRes..84..168Y }} as well as the oldest parasitic lice{{Cite journal |last1=Zhang |first1=Yanjie |last2=Rasnitsyn |first2=Alexandr P. |last3=Zhang |first3=Weiwei |last4=Song |first4=Fan |last5=Shih |first5=Chungkun |last6=Ren |first6=Dong |last7=Wang |first7=Yongjie |last8=Li |first8=Hu |last9=Gao |first9=Taiping |date=February 2024 |title=Stem chewing lice on Cretaceous feathers preserved in amber |url=https://linkinghub.elsevier.com/retrieve/pii/S0960982224000277 |journal=Current Biology |language=en |volume=34 |issue=4 |pages=916–922.e1 |doi=10.1016/j.cub.2024.01.027|pmid=38320551 |bibcode=2024CBio...34E.916Z }} and the oldest members of the parasitic insect order Strepsiptera.{{Cite journal |last1=Pohl |first1=Hans |last2=Wipfler |first2=Benjamin |last3=Boudinot |first3=Brendon |last4=Beutel |first4=Rolf Georg |year=2020 |title=On the value of Burmese amber for understanding insect evolution: Insights from †Heterobathmilla – an exceptional stem group genus of Strepsiptera (Insecta) |journal=Cladistics |language=en |volume=37 |issue=2 |pages=211–229 |doi=10.1111/cla.12433 |issn=1096-0031 |pmid=34478185 |doi-access=free}} The winged insect Aristovia is transitional between the extinct "Grylloblattodea" and modern wingless Grylloblattidae (ice crawlers).{{Cite journal |last1=Cui |first1=Yingying |last2=Bardin |first2=Jérémie |last3=Wipfler |first3=Benjamin |last4=Demers-Potvin |first4=Alexandre |last5=Bai |first5=Ming |last6=Tong |first6=Yi-Jie |last7=Chen |first7=Grace Nuoxi |last8=Chen |first8=Huarong |last9=Zhao |first9=Zhen-Ya |last10=Ren |first10=Dong |last11=Béthoux |first11=Olivier |date=2024-03-07 |title=A winged relative of ice-crawlers in amber bridges the cryptic extant Xenonomia and a rich fossil record |url=https://onlinelibrary.wiley.com/doi/10.1111/1744-7917.13338 |journal=Insect Science |volume=31 |issue=5 |pages=1645–1656 |language=en |doi=10.1111/1744-7917.13338 |pmid=38454304 |issn=1672-9609}} Over a dozen species each of Myriapoda (millipedes and centipedes, among others) and Entognatha (springtails, among others) have also been reported, along with a number of woodlice (representing some of the oldest records of the group) and various aquatic crustaceans.

A wide variety of other invertebrates have been reported. These include gastropods, including freshwater and land snails, the oldest modern onychophoran (also known as velvet worms) Cretoperipatus,{{Cite journal |last1=Oliveira |first1=I. |last2=Bai |first2=M. |last3=Jahn |first3=H. |last4=Gross |first4=V. |last5=Martin |first5=C. |last6=Hammel |first6=J. U. |last7=Zhang |first7=W. |last8=Mayer |first8=G. |year=2016 |title=Earliest Onychophoran in Amber Reveals Gondwanan Migration Patterns |journal=Current Biology |language=en |volume=26 |issue=19 |pages=2594–2601 |doi=10.1016/j.cub.2016.07.023 |pmid=27693140 |doi-access=free|bibcode=2016CBio...26.2594O }} as well as nematodes, nematomorphs, annelids and flatworms.

File:Fossil frog in amber.png in Burmese amber ]]

Only a handful of vertebrates have been described from Burmese amber, these include the albanerpetontid (a group of extinct salamander-like amphibians) Yaksha, the frog Electrorana, a number of primitive toothed birds belonging to the extinct clade Enantiornithes, including the named species Elektorornis and Fortipesavis, the lizards Protodraco (suggested to be the oldest agamid{{Cite journal |last1=Wagner |first1=Philipp |last2=Stanley |first2=Edward L. |last3=Daza |first3=Juan D. |last4=Bauer |first4=Aaron M. |date=August 2021 |title=A new agamid lizard in mid-Cretaceous amber from northern Myanmar |url=https://linkinghub.elsevier.com/retrieve/pii/S0195667121000604 |journal=Cretaceous Research |language=en |volume=124 |pages=104813 |doi=10.1016/j.cretres.2021.104813|bibcode=2021CrRes.12404813W }}), Cretaceogekko (suggested to be the oldest modern gecko), Electroscincus (the oldest known skink{{Cite journal |last1=Daza |first1=J. D. |last2=Stanley |first2=E. L. |last3=Heinicke |first3=M. P. |last4=Leah |first4=C. |last5=Doucet |first5=D. S. |last6=Fenner |first6=K. L. |last7=Arias |first7=J. S. |last8=Smith |first8=R. D. A. |last9=Peretti |first9=A. M. |last10=Aung |first10=N. N. |last11=Bauer |first11=A. M. |year=2024 |title=Compound osteoderms preserved in amber reveal the oldest known skink |journal=Scientific Reports |volume=14 |issue=1 |at=15662 |doi=10.1038/s41598-024-66451-w |doi-access=free|pmid=38977836 |pmc=11231356 |bibcode=2024NatSR..1415662D }}) Barlochersaurus,{{Cite journal |last1=Wang |first1=Miaoyan |last2=Xing |first2=Lida |date=2020-03-04 |title=A Brief Review of Lizard Inclusions in Amber |url=http://eaapublishing.org/journals/index.php/biosis/article/view/50 |journal=Biosis: Biological Systems |volume=1 |issue=1 |pages=39–53 |doi=10.37819/biosis.001.01.0050 |issn=2707-9783|doi-access=free }} Oculudentavis (formerly erroneously considered to be a bird),{{Cite journal |last1=Bolet |first1=Arnau |last2=Stanley |first2=Edward L. |last3=Daza |first3=Juan D. |last4=Arias |first4=J. Salvador |last5=Čerňanský |first5=Andrej |last6=Vidal-García |first6=Marta |last7=Bauer |first7=Aaron M. |last8=Bevitt |first8=Joseph J. |last9=Peretti |first9=Adolf |last10=Evans |first10=Susan E. |date=August 2021 |title=Unusual morphology in the mid-Cretaceous lizard Oculudentavis |url=https://linkinghub.elsevier.com/retrieve/pii/S0960982221007387 |journal=Current Biology |language=en |volume=31 |issue=15 |pages=3303–3314.e3 |doi=10.1016/j.cub.2021.05.040|pmid=34129826 |bibcode=2021CBio...31E3303B |hdl=11336/148383 |hdl-access=free }} and the snake Xiaophis.{{Cite journal |last1=Xing |first1=Lida |last2=Caldwell |first2=Michael W. |last3=Chen |first3=Rui |last4=Nydam |first4=Randall L. |last5=Palci |first5=Alessandro |last6=Simões |first6=Tiago R. |last7=McKellar |first7=Ryan C. |last8=Lee |first8=Michael S. Y. |last9=Liu |first9=Ye |last10=Shi |first10=Hongliang |last11=Wang |first11=Kuan |last12=Bai |first12=Ming |date=2018-07-06 |title=A mid-Cretaceous embryonic-to-neonate snake in amber from Myanmar |journal=Science Advances |language=en |volume=4 |issue=7 |pages=eaat5042 |doi=10.1126/sciadv.aat5042 |issn=2375-2548 |pmc=6051735 |pmid=30035227|bibcode=2018SciA....4.5042X }} An indeterminate theropod dinosaur is known from a tail with preserved feathers.{{Cite journal |last1=Xing |first1=Lida |last2=McKellar |first2=Ryan C. |last3=Xu |first3=Xing |last4=Li |first4=Gang |last5=Bai |first5=Ming |last6=Persons |first6=W. Scott |last7=Miyashita |first7=Tetsuto |last8=Benton |first8=Michael J. |last9=Zhang |first9=Jianping |last10=Wolfe |first10=Alexander P. |last11=Yi |first11=Qiru |last12=Tseng |first12=Kuowei |last13=Ran |first13=Hao |last14=Currie |first14=Philip J. |date=December 2016 |title=A Feathered Dinosaur Tail with Primitive Plumage Trapped in Mid-Cretaceous Amber |url=https://linkinghub.elsevier.com/retrieve/pii/S0960982216311939 |journal=Current Biology |language=en |volume=26 |issue=24 |pages=3352–3360 |doi=10.1016/j.cub.2016.10.008|pmid=27939315 |bibcode=2016CBio...26.3352X |hdl=1983/d3a169c7-b776-4be5-96af-6053c23fa52b |hdl-access=free }}

A wide variety of plants have been reported from the deposit. These include flowering plants, conifers, ferns, lycophytes and bryophytes.

A number of fungi species have been reported, as well as various microorganisms.

The amber is recorded as originating from Yunnan Province as early as the first century AD according to the Book of the Later Han. The trade of Burmese amber into China during the Han Dynasty has been confirmed by Fourier-transform infrared spectroscopy (FTIR) analysis of amber artifacts from the Eastern Han Dynasty (25 - 220 CE).{{Cite journal|last1=Chen|first1=Dian|last2=Zeng|first2=Qingshuo|last3=Yuan|first3=Ye|last4=Cui|first4=Benxin|last5=Luo|first5=Wugan|date=November 2019|title=Baltic amber or Burmese amber: FTIR studies on amber artifacts of Eastern Han Dynasty unearthed from Nanyang|url=https://linkinghub.elsevier.com/retrieve/pii/S1386142519306602|journal=Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy|language=en|volume=222|pages=117270|doi=10.1016/j.saa.2019.117270|pmid=31226615|bibcode=2019AcSpA.22217270C|s2cid=195261188}} It was first mentioned in European sources by the Jesuit Priest Álvaro Semedo who visited China in 1613, it was described as being "digged out of mines, and sometimes in great pieces, it is redder than our amber though not so cleane".Zherikhin, V.V., Ross, A.J., 2000. [https://www.biodiversitylibrary.org/bibliography/53542#/summary A review of the history, geology and age of Burmese amber (Burmite).] Bulletin of the Natural History Museum, London (Geology) 56 (1), 3–10. The locality itself has been known to European explorers since the 1800s with visitation to the Hukawng Valley by Simon Fraser Hannay in 1836–1837.{{cite book |last1=Ross |first1=A. |last2=Mellish |first2=C. |last3=York |first3=P. |last4=Craighton |first4=B. |editor-last=Penney |editor-first=D. |title=Biodiversity of Fossils in Amber from the Major World Deposits |publisher= Siri Scientific Press |date=2010 |pages=116–136 |chapter=Chapter 12: Burmese amber |isbn=978-0-9558636-4-6}} At that time the principle products of the valley mines were salt, gold, and amber, with the majority of gold and amber being bought by Chinese traders. Hannay visited the amber mines themselves on March 21, 1836, and he noted that the last three miles to the mines were marked with numerous abandoned pits, up to {{convert|15|ft|m|abbr=on}} in depth, where amber had been dug in the past. The mining had moved over the hill to a series of 10 pits but no visible amber was seen, suggesting that miners possibly hid the amber found that day before the party arrived. Mining was being performed manually at the time through the use of sharpened bamboo rods and small wooden shovels. Finer pieces of amber were recovered from the deeper pits, with clear yellow being recovered from depths of {{convert|40|ft|m|abbr=on}} The recovered amber was bought with silver or often exchanged for jackets, hats, copper pots, or opium among other goods. mixed and lower quality amber was sold from around {{frac2|1|2|}} ticals to 4 rupees per seer. Pieces that were considered high quality or fit for use as ornamentation were described as expensive, and price varied depending on the clarity and color of the amber. Women of the valley were noted to wear amber earrings as part of their jewelry.{{cite journal |last1=Pemberton |first1=R. B. |year=1837 |title=Abstract of the Journal of a route travelled by Cap. Hannay from the Capital of Ava to the Amber Mines of the Hukong valley in the South east frontier of Assam |journal=Journal of the Asiatic Society of Bengal |volume=64 |pages=248–278}} In 1885 the Konbaung dynasty was annexed to the British Raj and a survey of the area was conducted by Dr. Fritz Noetling on behalf of the Geological Survey of India. The final research before Burmese independence in 1947 was conducted by Dr. H.L. Chhibber in 1934, who provided the most detailed description of Burmite occurrences.

While a 1892 study considered the amber likely to be Miocene in age, a study by Theodore Dru Alison Cockerell in 1916 noted archaic nature of the insects, and concluded that the amber must be older, and possibly as old as the Late Cretaceous. Various later authors during the mid-late 20th century suggested either a Paleocene-Eocene or an Late Cretaceous age. A Cretaceous age was confirmed during the early 2000s. While during the 20th century and the first decade of the 21st century research on the deposit was low intensity, during the mid-2010s there was a great increase number of papers published on the deposit, numbering hundreds every year, with a plurality coming from Chinese researchers,{{Cite news |title=Research on amber from a war-torn part of Myanmar is surging |newspaper=The Economist |url=https://www.economist.com/graphic-detail/2022/09/22/research-on-amber-from-a-war-torn-part-of-myanmar-is-surging |access-date=2023-07-04 |issn=0013-0613}} rising from a few dozen species described per year prior to 2014 to over 350 in 2020, though this number had fallen to just over 250 by 2023. Both the great increase in the amber volume coming out of the mines, as well as a 2013 conference and a 2015 Burmese amber special issue in the journal Cretaceous Research have been cited as factors in the boom of publications.{{Cite report |url=https://www.science.org/content/article/violent-conflict-myanmar-linked-boom-fossil-amber-research-study-claims |title=Violent conflict in Myanmar linked to boom in fossil amber research, study claims |last=Ortega |first=Rodrigo Pérez |date=2022-09-29 |publisher=Science |doi=10.1126/science.adf0973 |language=en}}

{{See also|Kachin conflict|Internal conflict in Myanmar}}

File:Noje Bum amber.jpg

Leeward Capital Corp, a small Canadian mining firm, began exporting amber from Myanmar during the 1990s, resulting in the description of a number of fossil species from the deposit.{{Cite web |date=2022-04-17 |title=The return of Burmite amber |url=https://depositsmag.com/2022/04/17/the-return-of-burmite-amber/ |access-date=2024-10-24 |website=Deposits |language=en-US}} During the late 2000s, Burmese amber production began to increase as a result of the exhaustion of Chinese amber mines and greater trade between Myanmar and China in general, with the amber trade being initially unaffected by the outbreak of renewed conflict between the Kachin Independence Army, an armed rebel group seeking to scede from Myanmar, and the Burmese armed forces (Tatmadaw) in 2011. Despite the conflict between them, there was apparently a tacit agreement between the two groups to keep the amber trade flowing, with the KIA controlling the mines, while the Tatmadaw controlled their export to China, with both collecting taxes on the trade.{{Cite journal |last1=Dunne |first1=Emma M. |last2=Raja |first2=Nussaïbah B. |last3=Stewens |first3=Paul P. |last4=Zin-Maung-Maung-Thein |last5=Zaw |first5=Khin |date=2022-09-29 |title=Ethics, law, and politics in palaeontological research: The case of Myanmar amber |journal=Communications Biology |language=en |volume=5 |issue=1 |page=1023 |doi=10.1038/s42003-022-03847-2 |issn=2399-3642 |pmc=9522859 |pmid=36175597}} In 2016, the KIA took full control of the amber mines, and controlled amber export via "various licenses, taxes, restrictions on the movement of labor and enforced auctions".{{Cite journal|last=Peretti|first=Adolf|date=December 2021|title=An alternative perspective for acquisitions of amber from Myanmar including recommendations of the United Nations Human Rights Council|journal=Journal of International Humanitarian Action|language=en|volume=6|issue=1|pages=12|doi=10.1186/s41018-021-00101-y|s2cid=235174183|issn=2364-3412 |doi-access=free }} In June 2017 the Tatmadaw seized control of the mines from the KIA.{{Cite web|last=Lawton|first=Graham|title=Blood amber: The exquisite trove of fossils fuelling war in Myanmar|url=https://www.newscientist.com/article/mg24232280-600-blood-amber-the-exquisite-trove-of-fossils-fuelling-war-in-myanmar/|access-date=2020-02-04|website=New Scientist|language=en-US}}

The main amber market in Myanmar is Myitkyina. Most Burmese amber is exported (primarily smuggled) into China, with the primary Chinese market being in Tengchong, Yunnan, with an estimated 100 tonnes of Burmese amber passing into the city in 2015, with a then estimated value between five and seven billion yuan, where it is primarily used for jewelry. Burmese amber was estimated to make up 30% of Tenchong's gemstone market (the rest being Myanmar Jade), and was declared one of the city's eight main industries by the local government.{{Cite journal |last1=Rippa |first1=Alessandro |last2=Yang |first2=Yi |date=July 2017 |title=The Amber Road: Cross-Border Trade and the Regulation of the Burmite Market in Tengchong, Yunnan |journal=TRaNS: Trans -Regional and -National Studies of Southeast Asia |language=en |volume=5 |issue=2 |pages=243–267 |doi=10.1017/trn.2017.7 |issn=2051-364X |doi-access=free}} The presence of calcite veins are a major factor in determining the gem quality of pieces, with pieces with a large number of veins having significantly lower value.

The working conditions at the mines have been described as extremely unsafe, down {{convert|100|m|ft|abbr=on}} deep pits barely wide enough to crawl through, with no accident compensation. Sales of amber were alleged to help fund the Kachin conflict by various news organisations in 2019.{{Cite news|url=https://www.theatlantic.com/science/archive/2019/08/amber-fossil-supply-chain-has-dark-human-cost/594601/|title=The Human Cost of Amber|last=Gammon|first=Katharine|work=The Atlantic|access-date=2020-02-04|issn=1072-7825}}{{Cite web|url=https://www.newscientist.com/article/2214875-military-now-controls-myanmars-scientifically-important-amber-mines/|title=Military now controls Myanmar's scientifically important amber mines|last=Lawton|first=Graham|website=New Scientist|language=en-US|access-date=2020-02-04}} Interest in this discussion rose in March 2020 after the highly publicised description of Oculudentavis, which made the cover of Nature.{{Cite news|last=Joel|first=Lucas|url=https://www.nytimes.com/2020/03/11/science/amber-myanmar-paleontologists.html|title=Some Paleontologists Seek Halt to Myanmar Amber Fossil Research|date=2020-03-11|work=The New York Times|access-date=2020-03-13|language=en-US|issn=0362-4331}} On April 21, 2020, the Society of Vertebrate Paleontology (SVP) published a letter of recommendation to journal editors asking for "a moratorium on publication for any fossil specimens purchased from sources in Myanmar after June 2017 when the Myanmar military began its campaign to seize control of the amber mining".{{Cite book|last1=Rayfield|first1=Emily J.|url=http://vertpaleo.org/GlobalPDFS/SVP-Letter-to-Editors-FINAL.aspx|title=Fossils from conflict zones and reproducibility of fossil-based scientific data|last2=Theodor|first2=Jessica M.|last3=Polly|first3=P. David|publisher=Society for Vertebrate Paleontology|year=2020|pages=1–2|access-date=2020-04-28|archive-date=2021-01-26|archive-url=https://web.archive.org/web/20210126200125/http://vertpaleo.org/GlobalPDFS/SVP-Letter-to-Editors-FINAL.aspx|url-status=dead}} On April 23, 2020 Acta Palaeontologica Polonica stated that it would not accept papers on Burmese amber material collected from 2017 onwards, after the Burmese military took control of the deposit, requiring "certification or other demonstrable evidence, that they were acquired before the date both legally and ethically".{{Cite web|title=News - Acta Palaeontologica Polonica|url=https://www.app.pan.pl/news.html|website=www.app.pan.pl|access-date=2020-05-19}} On May 13, 2020, the Journal of Systematic Palaeontology published an editorial stating that it would no longer consider papers based whole or in part on Burmese amber material, regardless of whether in historic collections or not.{{Cite journal|last1=Barrett|first1=Paul M.|last2=Johanson|first2=Zerina|date=2020-05-13|title=Editorial: Myanmar (Burmese) Amber Statement|journal=Journal of Systematic Palaeontology|language=en|pages=1|doi=10.1080/14772019.2020.1764313|issn=1477-2019|doi-access=free}} On 30 June 2020, a statement from the International Palaeoentomological Society was published in response to the SVP, criticising the proposal to ban publishing on Burmese amber material.{{Cite journal|last1=Szwedo|first1=Jacek|last2=Wang|first2=Bo|last3=Soszyńska-Maj|first3=Agnieszka|last4=Azar|first4=Dany|last5=Ross|first5=Andrew J.|date=2020-06-30|title=International Palaeoentomological Society Statement|url=https://www.mapress.com/j/pe/article/view/palaeoentomology.3.3.1|journal=Palaeoentomology|volume=3|issue=3|pages=221–222|doi=10.11646/palaeoentomology.3.3.1|issn=2624-2834|doi-access=free}} In August 2020, a comment from over 50 authors was published in PalZ responding to the SVP statement. The authors disagreed with the proposal of a moratorium, describing the focus on the Burmese amber as "arbitrary" and that "The SVP's recommendation for a moratorium on Burmese amber affects fossil non-vertebrate research much more than fossil vertebrate research and clearly does not represent this part of the palaeontological community."{{Cite journal|last1=Haug|first1=Joachim T.|last2=Azar|first2=Dany|last3=Ross|first3=Andrew|last4=Szwedo|first4=Jacek|last5=Wang|first5=Bo|last6=Arillo|first6=Antonio|last7=Baranov|first7=Viktor|last8=Bechteler|first8=Julia|last9=Beutel|first9=Rolf|last10=Blagoderov|first10=Vladimir|last11=Delclòs|first11=Xavier|display-authors=2|date=September 2020|title=Comment on the letter of the Society of Vertebrate Paleontology (SVP) dated April 21, 2020 regarding "Fossils from conflict zones and reproducibility of fossil-based scientific data": Myanmar amber|journal=PalZ|language=en|volume=94|issue=3|pages=431–437|doi=10.1007/s12542-020-00524-9|issn=0031-0220|doi-access=free|bibcode=2020PalZ...94..431H |hdl=2445/175747|hdl-access=free}}

The conclusion that Burmese amber funded the Tatmadaw was disputed by George Poinar and Sieghard Ellenberger, who found that the supply of amber collapsed after the 2017 takeover of the mines by the Tatmadaw, and that most of the current circulation of amber in Chinese markets was extracted prior to 2017.{{Cite journal|last1=Poinar|first1=George|last2=Ellenberger|first2=Sieghard|date=April 2020|title=Burmese Amber Fossils, Mining, Sales and Profits|url=http://doi.org/10.30486/gcr.2020.1900981.1018|journal=Geoconservation Research|volume=3|issue=1|doi=10.30486/gcr.2020.1900981.1018}} A story in Science in 2019 stated: "Two former mine owners, speaking through an interpreter in phone interviews, say taxes have been even steeper since government troops took control of the area. Both shut their mines when they became unprofitable after the government takeover, and almost all deep mines are now out of business, dealers here corroborate. Only shallow mines and perhaps a few secret operations are still running."{{Cite journal|last=Sokol|first=Joshua|date=2019-05-23|title=Fossils in Burmese amber offer an exquisite view of dinosaur times—and an ethical minefield|journal=Science|doi=10.1126/science.aay1187|s2cid=194317225|issn=0036-8075}} There were around 200,000 miners working in the Hukawng valley mines prior to the takeover by the Tatmadaw, which shrunk to 20,000 or less after the military operations. Adolf Peretti, a gemologist who owns a museum with Burmese amber specimens, noted that the 2017 cutoff suggested by the SVP does not take into account that the export of Burmese amber prior to 2017 was also funding internal conflict in Myanmar due to the control by the KIA. Much of the amber cutting since 2017 has been done in internally displaced person camps, under humanitarian and non-conflict conditions.

Other deposits of amber are known from several regions in Myanmar, with noted deposits in the Shwebo District of the Sagaing Region, from the Pakokku and Thayet districts of Magway Region and the Bago District of the Bago Region.{{cite journal |last1=Zherikhin |first1=V. V. |last2=Ross |first2=A. J. |year=2000 |title=A review of the history, geology and age of Burmese amber burmite |journal=Bulletin of the Natural History Museum, Geology Series}}

A 2018 study on an amber deposit from Tilin in central Myanmar indicated that deposit to be 27 million years younger than the Hukawng deposit, dating to approximately 72 million years old, placing it in the latest Campanian age. The deposit was associated with an overlying tuffaceous layer, and underlying nodules of brown sandstone yielded remains of the ammonite Sphenodiscus. Within a number of arthropod specimens were described though much more poorly preserved than specimens in the Hukawng amber. These include members of Hymenoptera (Braconidae, Diapriidae, Scelionidae) Diptera (Ceratopogonidae, Chironomidae) Dictyoptera (Blattaria, Mantodea) planthoppers, Berothidae and bark lice (Lepidopsocidae) as well as extant ant subfamilies Dolichoderinae and tentatively Ponerinae, as well as fragments of moss.{{Cite journal |last1=Zheng |first1=D. |last2=Chang |first2=S.-C. |last3=Perrichot |first3=V. |last4=Dutta |first4=S. |last5=Rudra |first5=A. |last6=Mu |first6=L. |last7=Kelly |first7=R. S. |last8=Li |first8=S. |last9=Zhang |first9=Q. |last10=Zhang |first10=Q. |last11=Wong |first11=J. |date=December 2018 |title=A Late Cretaceous amber biota from central Myanmar |journal=Nature Communications |language=en |volume=9 |issue=1 |pages=3170 |doi=10.1038/s41467-018-05650-2 |issn=2041-1723 |pmc=6085374 |pmid=30093646|bibcode=2018NatCo...9.3170Z}}

The Hkamti site is located ca. 90 km southwest of the Angbamo site and predominantly consists of limestone, interbedded with mudstone and tuff, the amber is found in the unconsolidated mudstone/tuff layers. A crinoid was found attached to one amber specimen, alongside marine plant remains in the surrounding sediment, indicating deposition in a shallow marine setting. The amber is generally red-brown, and yellow colouration is rare, the amber is generally found as angular clasts, indicating short transport distance and is more brittle than other northern Myanmar ambers. Zircon dating has constrained the age of the deposit to the early Albian, c. 110 Ma, significantly older than the dates obtained from other deposits. Fauna found in the amber include: Archaeognatha, Diplopoda, Coleoptera, Araneae, Trichoptera, Neuroptera, Psocodea, Isoptera Diptera, Orthoptera, Pseudoscorpionida, Hymenoptera and Thysanoptera. A lizard, Retinosaurus, has also been described from the locality.{{Cite journal |last1=Čerňanský |first1=Andrej |last2=Stanley |first2=Edward L. |last3=Daza |first3=Juan D. |last4=Bolet |first4=Arnau |last5=Arias |first5=J. Salvador |last6=Bauer |first6=Aaron M. |last7=Vidal-García |first7=Marta |last8=Bevitt |first8=Joseph J. |last9=Peretti |first9=Adolf M. |last10=Aung |first10=Nyi Nyi |last11=Evans |first11=Susan E. |date=2022-01-31 |title=A new Early Cretaceous lizard in Myanmar amber with exceptionally preserved integument |journal=Scientific Reports |language=en |volume=12 |issue=1 |pages=1660 |bibcode=2022NatSR..12.1660C |doi=10.1038/s41598-022-05735-5 |issn=2045-2322 |pmc=8803969 |pmid=35102237}}

• {{portal-inline|Myanmar}}

{{Reflist}}

• [https://kdng.org/wp-content/uploads/2019/08/BloodAmber_English.pdf Blood Amber Military resource grab clears out indigenous peoples in Kachin State's Hugawng Valley Kachin Development Networking Group]

Category:Paleontological sites of Asia

Category:Paleontology in Myanmar