Preservation of Dominican amber fossil Essay

Introduction

Dominican gold originates from what is known as a dodo lagerst & A ; auml ; tte, this is a dodo location which is extremely singular for either the diverseness or quality of fossil saving. Amber bearing sedimentations are a specific sort of fossil bioaccumulation that preserves exceptionally good palaeobiological information from the past ( Martinez-Delcl & A ; ograve ; s et. al 2004 ) . Dominican gold became celebrated for its quality of dodos ( Iturralde-Vinent, 2001 ) , doing it a konservat lagerst & A ; auml ; tten, this type of saving conserves non-biomineralised tissues ( Mart & A ; iacute ; nez-Delcl & A ; oacute ; s, 2004 ) and as a consequence allows more accurate Reconstructions of past environments to be created, as palaeobiological information is preserved which is unable to be ascertained from the difficult bodied ‘shelly ‘ beings. Dodos preserved in Dominican amber include good preserved Fungis, algae, works remains, land invertebrates and land craniates ( P & A ; eacute ; rez-Gelabert, 1999 in Iturralde-Vinent, 2001 ) every bit good as a branchiate mushroom ( Poinar and Singer, 1990­ ) and mammalian hair ( Poinar, 1988 ) .

Amber became abundant throughout the universe in the Early Cretaceous, this coincided with the outgrowth and growing of the cone-bearing species Araucaruaceae and amber with inclusions have been dated back to the Lower Cretaceous ( Mart & A ; iacute ; nez-Delcl & A ; oacute ; s, 2004 ) . Dating of gold found in the Greater Antilles has been controversial, with a specific age scope unable to be settle upon, day of the months vary from Middle Eocene ( Schlee, 1990 ) , Upper Eocene ( Lambert et al. 1985 ) to lowermost Miocene ( Baroni-Urbani and Saunders 1980 ) ( in Henwood 1992 ) .

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The gold from the Dominican Republic is alone among golds of the universe for its lucidity ( Grimaldi, 1996 ) , as the gold found here is derived from rosin of the nonextant leguminous tree Hymenaea portera ( Poinar, 1991 ) . There are assorted phases of gold formation, the term rosin is used for the initial secernment made by the tree Hymenaea portera, and is normally mistaken for sap, this rosin production can be in little droplets or big measures. Resin is most frequently a xanthous coloring material, inert and resistant to disintegrate. Once the rosin has hardened ( to 1-2 on the Mohs graduated table ) and no thirster is fictile it is called copal ( Nudds & A ; Seldon 2007 ) . Over clip copal becomes amber, which forms as a consequence of entombment by overlying of sedimentary strata. Once buried the copal is subjected to intense heat and force per unit area and over millenary it cooks and finally reaches 2-3 on the Mohs graduated table, therefore transforming into gold.

The insects and animate beings are attracted to the rosin as a beginning of nutrient, due to its syrupy and adhesive nature they become stuck and later engulfed as they feed. This method of saving has led to at least 24 orders ( Lewis & A ; Grimaldi 1997 ) and 235 households ( Poinar 1992 ) of insects being discovered in Dominican gold.

Location of Dominican Amber

The Dominican Republic lies in the Greater Antilles archipelago on the island of Hispaniola, in the Caribbean ( Figure 1 ) . Amber has besides been reported from Haiti, Puerto Rico and Jamaica ( Iturralde-Vinent, 2001 ) , nevertheless Dominican gold contains a little per centum of bluish gold, a rare specimen which is bluish in natural visible radiation. This bluish gold is highly valuable and merely about 100kg are mined every twelvemonth ( Iturralde-Vinent, 2001 ) , this makes it expensive and has increased the economic value of Dominican amber. The gold with commercial value is largely found in nor’-east Santo Domingo, across the Cordillera Central ( Figure 2 ) .

Geology of the Dominican Republic amber locations

The island consists of the big Cordillera Central mountain scope which runs north west to south east across the island ( Figure 2 ) . The island of Hispanola is comprised of a broad scope of Late Tertiary stones, which are largely sedimentary in beginning and formed in subaerial to deep-marine depositional environments ( Mann et al. 1991 in Iturralde-Vinent, 2001 ) . Within the Cordillera Central scope two chief excavation sites have developed, the Eastern Mining District and the Northern Mining District. The Eastern Mining District is comprised of several 100s of metres of sedimentary stones, which are Neogene age, normally known as the Yanigua Formation ( Iturralde-Vinent, 2001 ) . This formation holds the largest sum of gold sedimentations in the Eastern country of the Dominican Republic and is largely comprised of pudding stones. Iturralde-Vinent ( 2001 ) found that the oblique lamination and erosional surfaces of these stones suggest a fluvial environment of deposition, this fluvial scene supports the work conducted by Mart & A ; iacute ; nez-Delcl & A ; oacute ; s ( 2004 ) who discovered that gold found here did non arise from that location, but had been transported by H2O flows to the concluding sedimentological sedimentations. Research by Brouwer and Brouwer ( 1982 ) found amber sedimentations with erosional characteristics, once more back uping the hypothesis that one time the gold is formed it is transported off from the site by fluvial procedures. The gold is often reworked and redistributed by flash inundations ( Iturralde-Vinent, 2001 ) and low-energy bays and coastal countries, such as estuaries and deltas, are favoured countries for brownish-yellow deposition, which correlates with Champetier et Al. ( 1982 ) who deduced that Yanigua formed in a low energy environment.

There are three chief excavation sites in the Dominican Republic dedicated to amber extraction, Sabana de la Mar and Bayaguana in the Eastern District and Septentrional in the Northern District ( Figure 3 ) . Mining in the country is carried out utilizing the bell cavity method, this method is extremely unsafe and uses small or no support construction in the mine. A shaft is dug down to the gold sedimentations and every bit much is removed as possible, until the mine becomes unstable and apt to fall in. Mining in the eastern country is easier than in the northern, as the gold at Sabana de la Mar and Bayaguana is encased in a softer brown coal than the gold to the North, nevertheless due to the softer nature of the stones, amber from this country is less desirable ( Dominican Amber, 2009 ) . Numerous noteworthy pieces of golds have been mined in the Dominican Republic, including a piece which weighed 7 kgs, this was the largest individual sedimentation discovered on the island, but is merely a fraction of the largest sedimentation of all time found, which originates from Malaysia and weighs 76 kgs ( Cameron, 2000 ) .

Biota of Dominican Amber

The Hymenaea portera tree, which produced the rosin from which the gold sedimentations originated, attracted a broad scope of zoology which later became trapped in the gold and preserved. Hall et Al. ( 2004 ) deduced that persons found in amber by and large belong to those taxa that are most likely to be trapped in tree rosin, these taxa include ; workss, arachnoids, insects, mollusk, crustaceans and craniates, which have all been recorded from Dominican gold. Once the animals have been attracted to the rosin, they become stuck and finally surrounded and encased. Pliny the Elder noticed every bit early as AD 77-79 that gold must hold been syrupy in order to incase the insects and other species within it, foregrounding the fact that gold and its biology have been long been known and studied.

Plants in Dominican gold

There are comparatively few workss found preserved in Dominican gold, nevertheless what was preserved were the foliages, seeds, flowers and pollen of the manufacturer tree ( Nudds & A ; Seldon, 2007 ) ( Photo 1 ) , which allowed an accurate categorization of the species of tree from which the rosin occurred ( Poinar 1991 ) . Flowers have besides been found from species such as Hippocrateaceae ( Photo 2 ) , Meliaceae and Leguminosease ( Poinar, 1992 )

Insects in Dominican gold

Insects and other species are widely known in Dominican gold, largely due to their broad copiousness. The most normally preserved species are the 1s which jumped from topographic point to topographic point, the winged insects and those which walked straight on the tree bark. Speciess such as Collembola and Crickets most likely became trapped in the rosin due to their method of leaping from topographic point to topographic point, during which they became trapped ( Vickery & A ; Poinar 1994, in Nudds & A ; Seldon 2007 ) .

Winged insects include a broad scope of species, but the preserved 1s were those which were most likely blown onto the rosin during flight. Other insect species which walked across the bark, such as earwigs, were prone to merely walking through the rosin and going edge.

Collembola are little in size and inhabit moist, dark home grounds incorporating decaying works remains ( Poinar 1992 ) . A assortment of species have been discovered in Dominican amber, including households Isotomidae, Entomobryidae and Sminthruidea ( Mari Mutt, 1983 ) . These species would skip from different locations as a signifier of motive power, they would frequently be trapped in the rosin and one time stuck they would widen their furcula to assistance flight ( Poinar, 1992 ) ( Photo 3 ) .

Winged insects comprise a broad scope of species, including dayflies, darning needles and damselflies. Mayflies are non strong flyers, they travel in droves and as a consequence are easy blown onto the rosin surface. There are non many species found in Dominican gold, nevertheless Poinar ( 1992 ) found that those which have been preserved closely represent the present twenty-four hours Leptophlebiiadae. Dragonflies and damselflies are much better at winging, hence there it is less likely that they will be blown onto the rosin surface and go at bay, as a consequence there are non many illustrations of darning needles trapped in Dominican gold.

Ants are highly common in brownish-yellow due to their changeless presence on the subdivisions of the Hymenaea portera tree. Ants are able to busy most ecological niches and so are highly successful, it is thought that about 15 genera have been reported ( Nudds & A ; Seldon 2007 ) . Baroni-Urbani ( 1980 ) was the first individual to depict emmets in Dominican gold and Trachymyrmex primaevus was one of the first ( Poinar 1992 ) . Besides found in Dominican gold is the oldest dodo bee, Trigona prisca ( photo 4 ) . Bees, particularly the Dominican trigonoid were prone to entrapment in gold, as they would build their nests from balls of rosin ( Poinar, 1992 ) .

Butterflies found in Dominican gold

Butterflies form portion of the order of Lepidoptera, and are characterised by holding graduated tables on all four wings ( Poinar, 1992 ) . Their saving in Dominican amber is non good known, and merely three species of butterflies have been found ( Hall et. al 2004 ) , these species nevertheless have been highly good studied ( Hall et al. 2004, Pe & A ; ntilde ; alver & A ; Grimaldi 2006 and Devries & A ; Poinar 1997 ) . Modern butterflies exhibit mutualism with other insects, such as emmets, work by Devries & A ; Poinar ( 1997 ) examined this butterfly-ant mutualism and concluded, from specimens in gold, that there was a specialized relationship between Theope and dolichoderine emmets every bit long as 15-20 million old ages ago. The saving of such item in Dominican gold has allowed a elaborate Reconstruction of past environments every bit good as the development of species. Hall et Al. ( 2004 ) taxonomically depict a new species of riodinid butterfly found encased in Dominican amber, Voltina dramba ( photo 7 ) . They found that the females would go trapped in the rosin whilst puting their eggs or resting on the Hymenaea portera subdivisions. The population was already little in the Antilles, Voltina dramba constituted less than 1 % of all butterfly species ( Smith et al. 1994 ) , as they were highly hapless at scattering over H2O, intending they were more prone to extinction and therefore seldom preserved in gold.

Crustaceans in Dominican gold

Crustaceous saving is non widely known in gold sedimentations from the Dominican Republic, nevertheless a figure of isopods have been described, including the first tellurian isopod Protosphaeroniscuc tertiarius ( Schmalfuss 1980 in Jass & A ; Klausmeier, 2000 ) . These slater would hold thrived in the bark of the Hymenaea portera. Besides found were amphipod species, which are believed to hold moved onto land during a chilling of the Oligocene, where they inhabited the moist foliage litter and undergrowth beneath the Hymenaea portera canopy. Once the clime began to warm once more, they remained as a tellurian species within that ecological niche ( Brousfield & A ; Poinar, 1995 ) .

Nematodes in Dominican gold

Nematodes ( besides known as tineas ) are highly common in Dominican gold. They are little in size and occupied moist environments, they can be free life or be found as parasites in other species. Poinar ( 1984 ) examined a drosophilid fly preserved in Dominican amber, which has been parasitized by roundworms, one time the fly had become trapped in the rosin, the roundworms left the organic structure and later became trapped excessively ( photo 5 ) , this allows far more accurate Reconstruction of species relationships. Dominican gold has produced a broad assortment of nematode specimens, nevertheless many of these samples have been ignored, in favor of larger samples, and as a consequence many are expecting designation and description ( Poinar, 1992 ) .

Arachnids in Dominican gold

The category Arachnida includes touchs, scorpians and spiders, nevertheless Scorpio saving in Dominican gold is rare, nevertheless false scorpions have been found, these have eight legs and metameric organic structures, yet are non classed as Scorpios. Psuedoscorpions inhabit moist environments such as within the foliage litter below the tree canopy. Spiders are comparatively common in gold, with about 44 households being described from Dominican amber entirely ( Nudds & A ; Seldon, 2007 ) . Theriidiea is the most common spider household, with legion species preserved, this is a consequence of them organizing webs within the crevasse of the Hymenaea portera, therefore heightening the likeliness of them going edge in the rosin.

Numerous spiders webs have been found preserved in gold, and some with quarries still attached, nevertheless none of these have originated from Dominican gold. Wunderlich ( 1986 ) ( in Poinar 1992 ) has found that 17 % of Dominican gold spiders are now extinct, this is a comparatively low per centum and Wunderlich believes this to be due to the Dominican Republic non experiencing the effects of clime alteration every bit much as other countries, such as the Baltic, therefore the species were able to accommodate more easy to the environment.

Touchs are infinitesimal arachnoids which can be soft or difficult bodied and both types have been discovered in Dominican gold. Touchs, such as Listrophoridea, have besides been discovered in concurrence with mammalian hair ( Poinar 1988 ) .

Mammalian hair in Dominican gold

Mammals have non been preserved in any gold from across the universe, nevertheless a footmark and some strands of hair have been preserved. In Dominican gold Poinar ( 1987 ) found hair which contained a touch and a beetling larva, both of which are parasites merely found on gnawers, therefore reasoning the hair ( photo 6 ) belonged to a member of the order Rodentia.

Vertebrates found in Dominican gold

Vetebrate saving in gold is highly rare, nevertheless there have been some noteworthy discoveries. It was Baltic gold which yeilded the first reliable toad ( Poinar & A ; Canatella, 1987 ) ( photo 8 ) , who believed that the fog was caught by a command which returned with it to a nest in a hole in the Hymenaea portera tree, where it later became restrained in the rosin. Birds have yet to be found preserved whole, most probably because they are excessively big to to the full continue and it would take multiple rosin eliminations to to the full incase them. The lone informations available from Dominican gold is that from plumes ( photo 9 ) and it was Poinar et Al. ( 1985 ) who foremost described the oldest bird dodos in the West Indies. Besides found are reptilians, although this is a big category, the lone species found are lizards ( photo 10 ) . Dominican gold has provided a twosome of specimens which have been studied in item ( B & A ; ouml ; hme, 1984 & A ; Rieppel, 1980, in Poinar, 1992 ) , though Poinar ( 1992 ) believes at least 11 lizard specimens have occurred from Dominican gold which are all now in private aggregation or museums. Unfortunatley due to high lizard populations around the universe, legion counterfeits of this species preserved in bogus golds have been created.

Baltic gold

The Dominican Republic is non the lone dodo lagerstatten for taxa preserved in gold, Baltic gold has created some of the largest sedimentations in the universe, with brownish-yellow occcuring as far off as Holland, Russia, Sweden and even Great Britain ( Poinar, 1992 ) . However the chief lagerst & A ; auml ; tte occurs on the Samland Peninsula in Russia, which boarders the Baltic sea. From this one loaction over half a million kg of golds have been extracted from mining happening in this century entirely. Baltic gold once more, like Dominican amber, is highly hard to day of the month, with most anticipations being formed on the footing of the fossil inclusions found. Poinar ( 1992 ) dates it as Early Eocene to Early Oligocene, therefore doing it somewhat older than the Dominican gold. Due to the different location, Baltic amber originates non from the Hymenaea portera, but from the Pinites succinifer. It is thought that in order to bring forth such big sedimentations of gold, that these trees must hold generated huge measures of rosin over millenary. Baltic gold has produced about all the same dodo species as Dominican gold, nevertheless due to its huge copiousness, Dominican amber specimens remain more extremely valued. The chief difference between Baltic and Dominican amber is their geographical location, by comparing and contrasting the species found preserved at each location, a much broader apprehension can be created as to the location and dispersion of different households and species across the universe at the clip of saving.

Animating past environments from Dominican gold

Dodos play a cardinal function in the Reconstruction of past environements, as they represent the climatic and environmental factors predominating at their clip of decease. Dodos encased in gold are frequently preserved in the last throes of decease, as they struggle to get away and frequently perish from exhaustion, therefore pulling marauders to their remains, which later become imobilised in the rosin. This type of form is utile in showing assorted predator-prey relationships and for analyzing relationships between species.

Due to the nature of some of the dodos preserved, such as the slater, butterflies and roundworms, it is possible to determine what kind of environment was happening. For illustration the presence of the colembolla and ispod species indicates there was a moist underbrush environment nowadays and the presence of Nepidae and Notonectidea indicates the presence of standing H2O in the country. From the different types of species preserved a wide image can be deduced as to the past home grounds of different taxa, this enables palaentologists to retrace the biogeographical history of specific clades ( Hall et al. 2004 ) , giving a greater apprehension of species associations and distributions.

Preservation of DNA in gold

There has long been a argument as to whether deoxyribonucleic acid ( DNA ) can be preserved in gold. When it was foremost discovered that gold was able to continue the cell construction of assorted taxa, it was thought that Deoxyribonucleic acid might perchance besides be preserved. There have been legion histories of successfully pull outing insect Deoxyribonucleic acid from gold ( Poinar et al. 1993, Cano et Al. 1992 and Desalle 1994 ) , nevertheless their consequences have non been backed by true empirical grounds, hence this topic remains contended. Austin et Al. ( 1997 ) ran a series of trials on insects in gold to turn out or confute this hypothesis. This whole probe stems from the belief that the rosin used to make the gold would suppress microbic debasement and therefore continue the insect tissue ( Henwood, 1993 ) . Austin et Al. ( 1997 ) cut away the gold and removed the insect tissue from 15 specimens, which were so tested for Deoxyribonucleic acid, they did non retrieve any reliable Deoxyribonucleic acid and hence disproved the other claims of DNA extraction.