Burmese amber, also known as Burmite or Kachin amber, is amber from the Hukawng Valley in northern Myanmar. The amber is dated to around 99 million years old, during the earliest part of the Cenomanian age of the Late Cretaceous. The amber is of significant palaeontological interest due to the diversity of flora and fauna contained as inclusions, particularly arthropods including insects and arachnids but also birds, lizards, snakes, frogs and fragmentary dinosaur remains. The amber has been known and commercially exploited since the first century AD, and has been known to science since the mid-nineteenth century. Research on the deposit has attracted controversy due to its role in funding internal conflict in Myanmar and hazardous working conditions in the mines where it is collected.
Geological context, depositional environment and age
The amber is found within the Hukawng Basin, a large Mesozoic-Cenozoic sedimentary basin within northern Myanmar. The strata have undergone folding and faulting. The basin is considered to be a part of the West Burma Block or Burma Terrane, which has a debated tectonic history. 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. Some members of the flora and fauna have Gondwanan affinities A recent paleomagnetic reconstruction finds that the Burma Terrane formed an island land mass in the Tethys Ocean during the Mid Creaceous at a latitude around 5-10 degrees south of the equator.
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. Lead-uranium dating of zircon crystals of volcanic clasts within the amber bearing horizons has given a maximum age of 98.79 ± 0.62 Ma, making the deposit earliest Cenomanian in age. 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 of it, 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.
The Burmese amber paleoforest is considered to have been an estuarian coastal tropical rainforest where resin was subsequently transported into a brackish shallow marine environment. The presence of troglobitic nocticolid cockroaches suggests the nearby presence of caves. The shell of a dead juvenile Puzosia (Bhimaites) species ammonite, four marine gastropod shells (including Mathilda) and littoral or supralittoral isopods entombed in a piece of amber with shell sand, along with growth of Isocrinid crinoids, corals and oysters on the surface of some pieces indicate tidal zone conditions. Additionally pholadid bivalve borings into amber specimens along with at least one pholadid which became trapped show that the resin was still fresh and unhardened when it was being moved into the tidal areas.The amber itself is primarily disc-shaped and flattened along the bedding plane, and is typically reddish brown, with the colour varying from shades of yellow to red. The opacity of the amber is variable from clear to opaque. Many amber pieces have thin calcite veins that are typically less than a millimetre thick, but are up to 4-5 mm wide. 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, though a pine origin has also been suggested.
Fauna and floraThe list of taxa is extraordinarily diverse, with over 42 classes, 108 orders, 569 families, 1017 genera and 1379 species described as of the end of 2019, with over 300 species described in 2019 alone, the vast majority (94%) of which are arthropods. A complete list of taxa up until the end of 2018 can be found in Ross 2018 And a supplement covering most of 2019 can be found in Ross 2019b. For the sake of brevity, a complete list of taxa is not given here, and the classification is mostly at family level. For a more complete list of taxa, see Paleobiota of Burmese amber.
InvertebratesWell over 1000 species of invertebrates are known from the deposit, including, notably the oldest members of Palpigradi (Electrokoenenia) and Schizomida (Mesozomus) the oldest Velvet worm (Cretoperipatus) and the only known fossil members of Mesothelae and Ricinulei since the Paleozoic. Chimerarachne is a unique stem spider still possessing a tail, with similar forms only known from the Paleozoic.
AraneaeForty-four families of spiders are known from the Burmese amber, including: Archaeidae, †Burmadictynidae, †Burmascutidae, †Burmathelidae, Clubionidae, Corinnidae, †Cretaceothelidae, Deinopidae, Dipluridae, †Eopsilodercidae, †Fossilcalcaridae, Hersiliidae, Hexathelidae, †Lagonomegopidae, Leptonetidae, Liphistiidae, †Micropalpimanidae, †Mongolarachnidae, Mysmenidae, Ochyroceratidae, Oecobiidae, Oonopidae, Oxyopidae, Palpimanidae, †Parvithelidae, Pholcidae, †Pholcochyroceridae, †Plumorsolidae, †Praearaneidae, †Praeterleptonetidae, Psechridae, Psilodercidae, Salticidae, Segestriidae, Telemidae, Tetrablemmidae, Tetragnathidae, Theridiosomatidae, Theridiidae, Thomisidae, Uloboridae and †Vetiaroridae.
AcariformesTwenty families of acariformes ae known from the Burmese amber, including: Anystidae, Archaeorchestidae, Bdellidae, Caeculidae, Cheyletidae, Enantioppiidae, Eremaeidae, Erythraeidae, Eupodidae, Gymnodamaeidae, Malaconothridae, Microtrombidiidae, Neoliodidae, Oribatellidae, Oribotritiidae, Resinacaridae, Smarididae, Trombellidae, Trombidiidae and Tuckerellidae.
OpilionesFive families of opiliones are known from the Burmese amber, including: Epedanidae, †Halithersidae, †Monooculricinuleidae, Sclerosomatidae and Stylocellidae.
PseudoscorpionesTwelve families of pseudoscorpions are known from the Burmese amber, including: Atemnidae, Cheiridiidae, Cheliferidae, Chernetidae, Chthoniidae, Feaellidae, Garypinidae, Hyidae Ideoroncidae, Neobisiidae, Pseudocheiridiidae and Withiidae.
ScorpionesSeven families of scorpions are known from the Burmese amber, including: Buthidae, Chaerilidae, †Chaerilobuthidae, †Palaeoburmesebuthidae, †Palaeoeuscorpiidae, †Palaeotrilineatidae and †Sucinolourencoidae.
ParasitiformesFive families of parasitiformes are known from the Burmese amber, including: Argasidae, †Deinocrotonidae, Ixodidae, Opilioacaridae and Polyaspididae.
SchizomidaOne genus of schizomidan is known from the Burmese amber: Mesozomus, which belongs to Hubbardiidae
PalpigradiOne genus of palpigradi is known: Electrokoenenia, which belongs to Eukoeneniidae
AmblypygiOne genus of Amblypygi is known: Kronocharon, which does not belong to any extant family.
SolfugaeOne genus of camel spider is known: Cushingia, which does not belong to any extant family.
ThelyphonidaTwo genera of whip scorpion are known: Mesothelyphonus, which belongs to Thelyphonidae and Burmathelyphonia, which does not belong to any extant family.
RicinuleiThree genera of Ricinulei are known: Hirsutisoma, ?Poliochera (an otherwise Carboniferous taxon) and Primoricinuleus, none of which belong to extant families
Fifteen families of Myriapods are known, including: Anthroleucosomatidae, Tingupidae, Glomeridellidae, Andrognathidae, Paradoxosomatidae, Polydesmidae, Polyxenidae, Synxenidae, Polyzoniidae, Siphoniulidae, Siphonophoridae, Siphonorhinidae, Zephroniidae, Cambalidae, Scolopendrellidae and †Burmanopetalidae.
EntognathaEight families of Entognathans are known, including: Campodeidae, Japygidae, Isotomidae, †Praentomobryidae, Tomoceridae, Neanuridae, Odontellidae and Sminthuridae.
Incertae cedisA species of the enigmatic long legged insect Chresmoda is known. As is the lice-like parasite Mesophthirus.
ArchaeognathaTwo families of archaeognathans are known from the Burmese amber: Machilidae and Meinertellidae
ZygentomaOne family of Zygentoman is known: Lepismatidae
Seven families of mayfly are known: †Australiphemeridae, Baetidae, Ephemeridae, Heptageniidae, †Hexagenitidae, Isonychiidae, Prosopistomatidae.
OdonataTwenty families of odonatan are known from the Burmese amber, including: Aeshnidae, †Araripegomphidae, †Burmacoenagrionidae, †Burmaeshnidae, †Burmagomphidae, †Burmaphlebiidae, Calopterygidae, Coenagrionidae, Dysagrionidae, Gomphaeschnidae, Gomphidae, Hemiphlebiidae, Libellulidae, Lindeniidae, Megapodagrionidae, †Mesomegaloprepidae, †Paracoryphagrionidae, Perilestidae, Platycnemididae, Platystictidae.
Over fifty families of hymenopterans have been described beginning with the papers of Cockerell who described a group of Bethylidae and Aulacidae species between 1917–1920. The monotypic family Melittosphecidae is only known from the Burmese amber species Melittosphex burmensis and eight species belonging to Aptenoperissus of the monotypic family Aptenoperissidae are also known. Originally described as an Aneuretinae ant Burmomyrma rossi was moved to the extinct Chrysidoidea family Falsiformicidae. A number of Formicidae species known, belonging to Baikuris (indet) Camelomecia janovitzi, Ceratomyrmex ellenbergeri, 11 species of Gerontoformica, 3 species of Haidomyrmex, Linguamyrmex vladi, 2 species of Zigrasimecia, Dhagnathos autokrator, Chonidris insolita, Aquilomyrmex huangi, Protoceratomyrmex revelatus and Linguamyrmex brevicornis. Other families include Ampulicidae, Braconidae, Cephidae, Ceraphronidae, Chalcididae, Chrysididae, Crabronidae, Diapriidae, Dryinidae, Embolemidae, Evaniidae, Gasteruptiidae, Heloridae, Ichneumonidae, Megalyridae, Megaspilidae, Mymaridae, Mymarommatidae, Pelecinidae, Platygastridae, Rhopalosomatidae. Rotoitidae, Sapygidae, Scelionidae, Sclerogibbidae, Scolebythidae, Sepulcidae, Sierolomorphidae, Siricidae, Sphecidae, Stephanidae, Tiphiidae, Vespidae, Xiphydriidae, †Aptenoperissidae, †Bryopompilidae, †Burmusculidae, †Chrysobythidae, †Dipterommatidae, †Diversinitidae, †Falsiformicidae, †Gallorommatidae, †Maimetshidae, †Myanmarinidae, †Othniodellithidae, †Praeaulacidae, †Proterosceliopsidae, †Serphitidae, †Spathiopterygidae, †Syspastoxyelidae and several incertae cedis taxa.
Forty-seven families of dipterans are known from the Burmese amber, including: Acroceridae, Anisopodidae, Apsilocephalidae, Apystomyiidae, Asilidae, Atelestidae, Blephariceridae, Bombyliidae, Cecidomyiidae, Ceratopogonidae, Chaoboridae, Chironomidae, Corethrellidae, Culicidae, Diadocidiidae, Dolichopodidae, Empididae, Hybotidae, Keroplatidae, Limoniidae, Lygistorrhinidae, Mycetophilidae, Mythicomyiidae, Nemestrinidae, Phoridae, Pipunculidae, Platypezidae, Psychodidae, Ptychopteridae, Rachiceridae, Rhagionidae, Scatopsidae, Sciaridae, Stratiomyidae, Tabanidae, Tanyderidae, Tipulidae, Valeseguyidae, Xylomyidae, †Cascopleciidae, †Chimeromyiidae, †Eremochaetidae, †Eucaudomyiidae, †Mysteromyiidae, †Rhagionemestriidae, †Tethepomyiidae, †Zhangsolvidae and several incertae cedis taxa.
ColeopteransEighty-nine families of coleopterans are known from the Burmese amber, including: Aderidae, Anthicidae, Anthribidae, †Apotomouridae, Belidae, Boganiidae, Bostrichidae, Brachypsectridae, Buprestidae, Cantharidae, Carabidae, Caridae, Cerambycidae, Cerophytidae, Cerylonidae, Chrysomelidae, Ciidae, Clambidae, Cleridae, Cucujidae, Cupedidae, Curculionidae, Cyclaxyridae, Dascillidae, Dermestidae, Drilidae, Dytiscidae, Elateridae, Elmidae, Endomychidae, Eucinetidae, Eucnemidae, Geotrupidae, Glaresidae, Gyrinidae, Histeridae, Hybosoridae, Hydraenidae, Hydrophilidae, Ithyceridae, Jacobsoniidae, Kateretidae, Laemophloeidae, Lampyridae, Latridiidae, Leiodidae, Lepiceridae, Lucanidae, Lycidae, Lymexylidae, Melandryidae, Meloidae, Melyridae, †Mesophyletidae, Monotomidae, Mordellidae, Nemonychidae, Nitidulidae, Oedemeridae, Ommatidae, Passalidae, †Parandrexidae, †Passalopalpidae, Passandridae, Prostomidae, Psephenidae, Ptiliidae, Ptinidae, Ptilodactylidae, Ripiphoridae, Rhysodidae, Salpingidae, Scarabaeidae, Scirtidae, Scraptiidae, Silphidae, Silvanidae, Smicripidae, Sphaeriusidae, Staphylinidae, Tenebrionidae, Tetratomidae, Thanerocleridae, Throscidae, Trogidae, Trogossitidae and Zopheridae.
Twenty-one families of neuropterans are known from the Burmese amber, including: Ascalaphidae, †Babinskaiidae, Berothidae, Chrysopidae, Coniopterygidae, †Corydasialidae, Dilaridae, †Dipteromantispidae, Hemerobiidae, Ithonidae, Kalligrammatidae, Mantispidae, †Mesochrysopidae, Myrmeleontidae, Nemopteridae, Nevrorthidae, Nymphidae, Osmylidae, Psychopsidae, Rachiberothidae, Sisyridae and several incertae cedis taxa.
HemipteraSixty five families of hemipterans are known from the Burmese amber, including: Achilidae, †Albicoccidae, Aleyrodidae, Aphrophoridae, Aradidae, †Burmacoccidae, †Burmitaphidae, Callaphididae, Cercopidae, Cicadellidae, Cicadidae, Cimicidae, Cixiidae, Coccidae, Coreidae, Cydnidae, Dictyopharidae, Dipsocoridae, †Dorytocidae, Enicocephalidae, Fulgoridae, Gelastocoridae, Gerridae, †Hodgsonicoccidae, Hydrometridae, Issidae, †Jubisentidae, †Juraphididae, Kinnaridae, †Kozariidae, †Lalacidae, Leptopodidae, †Liadopsyllidae, Margarodidae, Matsucoccidae, †Mimarachnidae, †Minlagerrontidae, Miridae, Monophlebidae, Naucoridae, Ochteridae, Ortheziidae,†Palaeoleptidae, †Parvaverrucosidae, †Perforissidae, †Protopsyllidiidae, †Procercopidae, Pseudococcidae, Reduvidae, Schizopteridae, †Sinoalidae, †Tajmyraphididae, Tettigarctidae, Tingidae, Tropiduchidae, Velocipedidae,Veliidae, †Weitschatidae, Xylococcidae, †Yetkhatidae, Nabidae, †Neazoniidae and several incertae cedis taxa.
DictyopteraTwenty families of dictyopterans are known from the Burmese amber, including: Blaberidae, †Blattulidae, Blattidae, †Caloblattinidae, Corydiidae, Ectobiidae, †Olidae, †Liberiblattinidae, †Alienopteridae, †Manipulatoridae †Umenocoleidae , Nocticolidae, †Pabuonqedidae Termites (†Archeorhinotermitidae, Hodotermitidae, Termitidae and Mastotermitidae) and mantid Burmantis.
MecopteraFive families of mecopteran are known, including: Bittacidae, Meropeidae, Mesopanorpodidae, †Pseudopolycentropodidae and †Dualulidae.
PsocopteraNine families of psocopteran are known, including: †Archaeatropidae, Compsocidae, Liposcelididae, Manicapsocidae, Pachytroctidae,Prionoglarididae, Psyllipsocidae, Sphaeropsocidae and Trogiidae.
OrthopteraSix families of orthopteran are known, including: †Elcanidae, Gryllidae, Mogoplistidae, Tetrigidae, Tettigoniidae and Tridactylidae
TrichopteraEight families of trichopteran are known, including: Calamoceratidae, †Dysoneuridae, Helicopsychidae, Hydroptilidae, Odontoceridae, Philopotamidae, Polycentropodidae and Psychomyiidae.
Five families of dermapteran are known, including: Anisolabididae, Diplatyidae, Labiduridae and Pygidicranidae.
EmbiopteraFour families of embiopteran are known, including: Clothodidae, Oligotomidae, Notoligotomidae and †Sorellembiidae.
NotopteraOne species of notopteran is known, a nymph ice crawler (Grylloblattidae) Sylvalitoralis cheni.
StrepsipteraFour families of strepsipteran are known, including: †Cretostylopidae, †Kinzelbachillidae, †Mengeidae, †Phthanoxenidae
LepidopteraFour families of lepidopteran are known, including: Douglasiidae, Gelechiidae, Gracillariidae and Micropterigidae.
MegalopteraOne species of megalopteran is known, Haplosialodes liui of the family Sialidae.
PhasmatodeaFour families of phasmatodean are known: †Archipseudophasmatidae, Phasmatidae. †Pterophasmatidae and Timematidae
ThysanopteraFour families of thrips are known, including: Aeolothripidae, †Rohrthripidae,Thripidae and Stenurothripidae.
PlecopteraTwo families of stoneflies are known, Perlidae and †Petroperlidae.
RaphidiopteraOne family of Raphidiopteran is known, †Mesoraphidiidae.
†TarachopteraOne family of Tarachopteran is known: †Tarachocelidae
†PermopsocidaOne family of Permopsocidan is known: †Archipsyllidae
ZorapteraMultiple species of Zorotypus and the monotypic genus Xenozorotypus are known.
NematodaFive families of nematodes are known, including: Cosmocercidae, Heterorhabditidae, Mermithidae, Thelastomatidae, Aphelenchoididae
NematomorphaOne genus of nematomorph is known: Cretachordodes (Chordodidae, Gordioidea)
Aside from the previously mentioned ammonites and marine gastropod shells, Seven families of terrestrial gastropod are known: Diplommatinidae, Pupinidae, Achatinidae, Punctidae, Valloniidae, Assimineidae and Cyclophoridae