Araucaria mirabilis
Encyclopedia
Araucaria mirabilis is an extinct species
of coniferous tree
s from Patagonia
, Argentina
. It belongs to the section
Bunya of the genus
Araucaria
; the only living species of which is Araucaria bidwillii
from Australia
.
A. mirabilis are known from large amounts of very well-preserved silicified
wood and cones
from the Cerro Cuadrado Petrified Forest, including tree trunks that reached 100 m (328.1 ft) in height in life. The site was buried by a volcanic eruption during the Middle Jurassic
, approximately 160 million years ago.
s of Araucaria mirabilis are found in great abundance in the Cerro Cuadrado Petrified Forest of Patagonia, Argentina. They were the dominant species
of a forest buried by a volcanic eruption about 160 million years ago.
The petrified forests of A. mirabilis were first discovered in 1919 by the German-Argentinean botanist Anselmo Windhausen. Noting that petrified cones
were being kept as souvenirs by local farmers in the area, he explored the region and discovered the site of the petrified forests in 1923. He sent the specimens he collected to the German botanist Walther Gothan in Berlin
in 1924. Gothan named them Araucaria windhauseni in honor of Windhausen in 1925.
However, the Italian
-Argentinean botanist Carlos Luigi Spegazzini
had also acquired specimens from the petrified forest from various sources. He tentatively identified the specimens as Araucarites mirabilis in 1924.
An American paleontological
expedition led by Elmer S. Briggs (1923–1924) of the Field Museum of Natural History
also discovered the petrified forests. The numerous specimens Riggs collected (who identified them as Araucaria) were later described by the American paleontologist and paleobotanist
George Reber Wieland as Proaraucaria elongata (1929), Proaraucaria mirabilis (1935), and Proaraucaria patagonica (1935). Wieland and Gothan interpreted the absence of separate petrified seeds as evidence that the cones did not shed their scales at the final growth year. This was originally stated by Wieland as a justification for its classification under a new genus Proaraucaria.
An emended description was published by the Scottish
paleobotanist Mary Gordon Calder
in 1953. Calder questioned the conclusions of Wieland and Gothan. She also discarded the earlier classification of Spegazzini of Araucarites. The latter is a form genus
, usually used for incomplete plant fossil specimens that resemble Araucaria but lack enough preserved details for more accurate classifications. Citing striking similarities with the extant Araucaria bidwillii
, Calder reclassified the specimens as Araucaria mirabilis.
. It is classified under the family
Araucariaceae
of the order
Pinales
. Its closest living relative is the Australia
n bunya bunya (Araucaria bidwillii
).
The genus name Araucaria is derived from the Spanish
exonym Araucanos ("from Arauco
"), referring to the Mapuche
people of Chile
and Argentina. The specific name mirabilis is from Latin
for "wondrous" or "amazing".
, some of the specimens measure 3.5 m (11.5 ft) in diameter and were at least 100 m (328.1 ft) in height when alive. The trees were preserved just as the cones
had finished maturing.
The cones are spherical, ovoid, to ellipsoidal in shape with a wide axis. They average at 2.5 to 8 cm (0.984251968503937 to 3.1 in) in length. The largest specimens are nearly 10 cm (3.9 in) in diameter. The center of the cones consist of a parenchymatous
pith
surrounded by fused vascular bundles (two for each bract-scale complex, with each vascular bundle containing resin
canals).
The bract
s have thick and wide woody wings tapering towards the base. They are around 13 to 16 mm (0.511811023622047 to 0.62992125984252 in) long and 10 mm (0.393700787401575 in) wide, including the wings. They are overlain by fertile scales containing one seed each, embedded on the upper surface. They are arranged helically
. The "ligules" (the free tip of the fertile scale characteristic of Araucaria) are 4 mm (0.15748031496063 in) wide, 1 to 2 mm (0.0393700787401575 to 0.078740157480315 in) high, and 5 mm (0.196850393700787 in) long.
The mature seeds of A. mirabilis are about 0.8 to 1.3 cm (0.31496062992126 to 0.511811023622047 in) long and 0.2 to 0.6 cm (0.078740157480315 to 0.236220472440945 in) wide. The seed integument has three layers of tissues - the sarcotesta
, the thickened sclerotesta
, and endotesta. It is fused to the nucellus (central portion of the ovule
) only at the base. The sclerotesta (the "shell") also exhibits a zigzag pattern of sclereids. The fossilized seeds are exquisitely preserved, showing both mature and immature stages. They often contain well-developed dicotyledon
ous embryos, indicating that they were capable of lying dormant
. The size of the cones did not indicate maturity as small cones around 5 cm (2 in) in diameter can be found with fully formed embryo
s. Most of the cones have been preserved before their seeds could be dispersed. Some cones, however, do not contain embryos and the naked axes of cones have also been recovered (described by Wieland as a separate species - Proaraucaria patagonica). It is believed that A. mirabilis sheds only its seeds but not the scales at maturity. Nevertheless, no separate petrified seeds or bracts have been recovered.
Small woody corm-like structures have also been found. Initially identified as "seedlings", are now known to be lignotuber
s.
However, the seeds of A. bidwillii are much larger, 5 to 6 cm (2 to 2.4 in) long and 2.5 to 3.5 cm (0.984251968503937 to 1.4 in) wide, than the seeds of A. mirabilis. A. bidwillii also exhibits cryptocotylar hypogeal
germination
(the cotyledon
s are non-photosynthetic and remain in the shell on germination), while there is evidence that indicates that A. mirabilis and other extinct members of the section Bunya exhibited epigeal
germination (the cotyledons are photosynthetic and expand above-ground). In addition, no reliably identifiable fossils of members of the section Bunya have been recovered from Australia
, the native range of A. bidwillii. The only existing species of Araucaria in South America today are Araucaria angustifolia
and Araucaria araucana
. Both belong to the section Araucaria of the genus. Setoguchi et al. (1998) have recommended that the extinct members of the section Bunya (which includes Araucaria sphaerocarpa of the United Kingdom
) be treated as a separate group.
A. mirabilis is found in association with other conifers, including Pararaucaria patagonica (not to be confused with the synonym
Proaraucaria patagonica of A. mirabilis), and Araucarites sanctaecrucis
. P. patagonica is also known from cones. It has no living descendants and its closest living relatives appear to be members of the modern family Cupressaceae
(cypresses). A. sanctaecrucis fossils consist of foliage and branches.
The fossils of the putative bracket fungus
Phellinites digiustoi are also found in the Cerro Cuadrado Petrified Forest. The latter was initially believed to be the oldest known mushroom-forming fungi (Agaricomycetes
). Later examinations now make it likely that P. digiustoi was, in fact, part of the periderm of the fossilized bark
of A. mirabilis.
It is also believed that the long necks of sauropod dinosaur
s may have evolved specifically for browsing the foliage of the typically very tall A. mirabilis and other Araucaria trees. Araucaria leaves required long digestion times and were low in protein
, but they were very energy-rich. This and the global distribution of vast forests of Araucaria makes it likely that they were the primary food sources for adult sauropods during the Jurassic. Juveniles, however, which lacked the bulk of the adults and required larger amounts of proteins for growth, probably subsisted on other plants.
A. mirabilis fossils have been found with damage resulting from beetle larva
e. These beetles are believed to be the ancestors of the most ancient lineage of bark beetle
s in the weevil
family (Curculionidae
) - the members of the tribe
Tomicini
, which are still serious pest
s of conifers today. They were probably host-specific
to members of the genus Araucaria since the Mesozoic
. Modern A. bidwillii are also hosts to primitive weevils from the family Megalopodidae
and leaf beetle
s from the family Nemonychidae
.
Araucaria forests were distributed globally and formed a major part of the woody flora of the Mesozoic era. The Cerro Cuadrado Petrified Forest is part of the La Matilde Formation
, dated to the Bathonian
to Oxfordian ages (164.7 to 155.7 million years ago) of the Middle
to Upper Jurassic. The area was once part of the subtropical and temperate
regions of the southern supercontinent
Gondwana
in the Mesozoic
era, a more or less continuous landmass consisting of what is now modern South America
, Africa
, Antarctica, Australia
, New Zealand
, and New Guinea
.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of coniferous tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s from Patagonia
Patagonia
Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
, Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
. It belongs to the section
Section (botany)
In botany, a section is a taxonomic rank below the genus, but above the species. The subgenus, if present, is higher than the section, and the rank of series, if present, is below the section. Sections are typically used to help organise very large genera, which may have hundreds of species...
Bunya of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Araucaria
Araucaria
Araucaria is a genus of evergreen coniferous trees in the family Araucariaceae. There are 19 extant species in the genus, with a highly disjunct distribution in New Caledonia , Norfolk Island, eastern Australia, New Guinea, Argentina, Chile, and southern Brazil.-Description:Araucaria are mainly...
; the only living species of which is Araucaria bidwillii
Araucaria bidwillii
Araucaria bidwillii, the Bunya Pine, is a large evergreen coniferous tree in the genus Araucaria, family Araucariaceae. It is native to south-east Queensland with two small disjunct populations in northern Queensland's World Heritage listed Wet Tropics, and many fine old specimens planted in New...
from Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
A. mirabilis are known from large amounts of very well-preserved silicified
Petrifaction
In geology, petrifaction, petrification or silicification is the process by which organic material is converted into stone by impregnation with silica. It is a rare form of fossilization...
wood and cones
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...
from the Cerro Cuadrado Petrified Forest, including tree trunks that reached 100 m (328.1 ft) in height in life. The site was buried by a volcanic eruption during the Middle Jurassic
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from 176-161 million years ago. In European lithostratigraphy, rocks of this Middle Jurassic age are called the Dogger....
, approximately 160 million years ago.
Discovery
FossilFossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s of Araucaria mirabilis are found in great abundance in the Cerro Cuadrado Petrified Forest of Patagonia, Argentina. They were the dominant species
Dominance (ecology)
Ecological dominance is the degree to which a species is more numerous than its competitors in an ecological community, or makes up more of the biomass...
of a forest buried by a volcanic eruption about 160 million years ago.
The petrified forests of A. mirabilis were first discovered in 1919 by the German-Argentinean botanist Anselmo Windhausen. Noting that petrified cones
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...
were being kept as souvenirs by local farmers in the area, he explored the region and discovered the site of the petrified forests in 1923. He sent the specimens he collected to the German botanist Walther Gothan in Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
in 1924. Gothan named them Araucaria windhauseni in honor of Windhausen in 1925.
However, the Italian
Italian people
The Italian people are an ethnic group that share a common Italian culture, ancestry and speak the Italian language as a mother tongue. Within Italy, Italians are defined by citizenship, regardless of ancestry or country of residence , and are distinguished from people...
-Argentinean botanist Carlos Luigi Spegazzini
Carlos Luigi Spegazzini
Carlos Luis Spegazzini, or Carlo Luigi Spegazzini, was an Italian-Argentinian botanist and mycologist. Spegazzini published about 100 scientific papers on vascular plants, describing around 1000 new taxa...
had also acquired specimens from the petrified forest from various sources. He tentatively identified the specimens as Araucarites mirabilis in 1924.
An American paleontological
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
expedition led by Elmer S. Briggs (1923–1924) of the Field Museum of Natural History
Field Museum of Natural History
The Field Museum of Natural History is located in Chicago, Illinois, USA. It sits on Lake Shore Drive next to Lake Michigan, part of a scenic complex known as the Museum Campus Chicago...
also discovered the petrified forests. The numerous specimens Riggs collected (who identified them as Araucaria) were later described by the American paleontologist and paleobotanist
Paleobotany
Paleobotany, also spelled as palaeobotany , is the branch of paleontology or paleobiology dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments , and both the evolutionary history of plants, with a...
George Reber Wieland as Proaraucaria elongata (1929), Proaraucaria mirabilis (1935), and Proaraucaria patagonica (1935). Wieland and Gothan interpreted the absence of separate petrified seeds as evidence that the cones did not shed their scales at the final growth year. This was originally stated by Wieland as a justification for its classification under a new genus Proaraucaria.
An emended description was published by the Scottish
Scottish people
The Scottish people , or Scots, are a nation and ethnic group native to Scotland. Historically they emerged from an amalgamation of the Picts and Gaels, incorporating neighbouring Britons to the south as well as invading Germanic peoples such as the Anglo-Saxons and the Norse.In modern use,...
paleobotanist Mary Gordon Calder
Mary Gordon Calder
Mary Gordon Calder was a Scottish paleobotanist. She is known for her work on Carboniferous fossil plants and Jurassic conifers.-Early years:...
in 1953. Calder questioned the conclusions of Wieland and Gothan. She also discarded the earlier classification of Spegazzini of Araucarites. The latter is a form genus
Form classification
Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships...
, usually used for incomplete plant fossil specimens that resemble Araucaria but lack enough preserved details for more accurate classifications. Citing striking similarities with the extant Araucaria bidwillii
Araucaria bidwillii
Araucaria bidwillii, the Bunya Pine, is a large evergreen coniferous tree in the genus Araucaria, family Araucariaceae. It is native to south-east Queensland with two small disjunct populations in northern Queensland's World Heritage listed Wet Tropics, and many fine old specimens planted in New...
, Calder reclassified the specimens as Araucaria mirabilis.
Taxonomy and nomenclature
Araucaria mirabilis belongs to section Bunya of the genus AraucariaAraucaria
Araucaria is a genus of evergreen coniferous trees in the family Araucariaceae. There are 19 extant species in the genus, with a highly disjunct distribution in New Caledonia , Norfolk Island, eastern Australia, New Guinea, Argentina, Chile, and southern Brazil.-Description:Araucaria are mainly...
. It is classified under the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Araucariaceae
Araucariaceae
Araucariaceae, commonly referred to as araucarians, is a very ancient family of coniferous trees. It achieved its maximum diversity in the Jurassic and Cretaceous periods, when it was distributed almost worldwide...
of the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Pinales
Pinales
The Order Pinales in the Division Pinophyta, Class Pinopsida comprises all the extant conifers. This order was formerly known as the Coniferales....
. Its closest living relative is the Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n bunya bunya (Araucaria bidwillii
Araucaria bidwillii
Araucaria bidwillii, the Bunya Pine, is a large evergreen coniferous tree in the genus Araucaria, family Araucariaceae. It is native to south-east Queensland with two small disjunct populations in northern Queensland's World Heritage listed Wet Tropics, and many fine old specimens planted in New...
).
The genus name Araucaria is derived from the Spanish
Spanish language
Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...
exonym Araucanos ("from Arauco
Arauco
Arauco or Araucanía may refer to:* Arauco, Chile, a city and municipality in Arauco Province, Chile* Arauco Province, a province in the Biobío Region of Chile* Arauco, Argentina, a town in Arauco Department, Argentina...
"), referring to the Mapuche
Mapuche
The Mapuche are a group of indigenous inhabitants of south-central Chile and southwestern Argentina. They constitute a wide-ranging ethnicity composed of various groups who shared a common social, religious and economic structure, as well as a common linguistic heritage. Their influence extended...
people of Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
and Argentina. The specific name mirabilis is from Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "wondrous" or "amazing".
Description
A large number of petrified tree trunks of A. mirabilis are found still standing in the Cerro Cuadrado Petrified Forest. Preserved in volcanic ashVolcanic ash
Volcanic ash consists of small tephra, which are bits of pulverized rock and glass created by volcanic eruptions, less than in diameter. There are three mechanisms of volcanic ash formation: gas release under decompression causing magmatic eruptions; thermal contraction from chilling on contact...
, some of the specimens measure 3.5 m (11.5 ft) in diameter and were at least 100 m (328.1 ft) in height when alive. The trees were preserved just as the cones
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...
had finished maturing.
The cones are spherical, ovoid, to ellipsoidal in shape with a wide axis. They average at 2.5 to 8 cm (0.984251968503937 to 3.1 in) in length. The largest specimens are nearly 10 cm (3.9 in) in diameter. The center of the cones consist of a parenchymatous
Parenchyma
Parenchyma is a term used to describe a bulk of a substance. It is used in different ways in animals and in plants.The term is New Latin, f. Greek παρέγχυμα - parenkhuma, "visceral flesh", f. παρεγχεῖν - parenkhein, "to pour in" f. para-, "beside" + en-, "in" + khein, "to pour"...
pith
Pith
Pith, or medulla, is a tissue in the stems of vascular plants. Pith is composed of soft, spongy parenchyma cells, which store and transport nutrients throughout the plant. In eudicots, pith is located in the center of the stem. In monocots, it extends also into flowering stems and roots...
surrounded by fused vascular bundles (two for each bract-scale complex, with each vascular bundle containing resin
Resin
Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. Resins are valued for their chemical properties and associated uses, such as the production of varnishes, adhesives, and food glazing agents; as an important source of raw materials...
canals).
The bract
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
s have thick and wide woody wings tapering towards the base. They are around 13 to 16 mm (0.511811023622047 to 0.62992125984252 in) long and 10 mm (0.393700787401575 in) wide, including the wings. They are overlain by fertile scales containing one seed each, embedded on the upper surface. They are arranged helically
Helix
A helix is a type of smooth space curve, i.e. a curve in three-dimensional space. It has the property that the tangent line at any point makes a constant angle with a fixed line called the axis. Examples of helixes are coil springs and the handrails of spiral staircases. A "filled-in" helix – for...
. The "ligules" (the free tip of the fertile scale characteristic of Araucaria) are 4 mm (0.15748031496063 in) wide, 1 to 2 mm (0.0393700787401575 to 0.078740157480315 in) high, and 5 mm (0.196850393700787 in) long.
The mature seeds of A. mirabilis are about 0.8 to 1.3 cm (0.31496062992126 to 0.511811023622047 in) long and 0.2 to 0.6 cm (0.078740157480315 to 0.236220472440945 in) wide. The seed integument has three layers of tissues - the sarcotesta
Sarcotesta
The sarcotesta is the outermost fleshy covering of Cycad seeds. Below this layer is usually the sclerotesta, the coating that makes direct contact with the cycad seed. In some species, however, there is an intermediate layer that is thought to be used in water retention and storage....
, the thickened sclerotesta
Sclerotesta
Sclerotesta is the innermost fleshy coating of cycad seeds, usually located directly below the Sarcotesta....
, and endotesta. It is fused to the nucellus (central portion of the ovule
Ovule
Ovule means "small egg". In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: The integument forming its outer layer, the nucellus , and the megaspore-derived female gametophyte in its center...
) only at the base. The sclerotesta (the "shell") also exhibits a zigzag pattern of sclereids. The fossilized seeds are exquisitely preserved, showing both mature and immature stages. They often contain well-developed dicotyledon
Dicotyledon
The dicotyledons, also known as dicots, are a group of flowering plants whose seed typically has two embryonic leaves or cotyledons. There are around 199,350 species within this group...
ous embryos, indicating that they were capable of lying dormant
Seed dormancy
Seed dormancy is a condition of plant seeds that prevents germination when the seeds are under optimal environmental conditions for germination. Living, non dormant seeds germinate when soil temperatures and moisture conditions are suited for cellular processes and division; dormant seeds do...
. The size of the cones did not indicate maturity as small cones around 5 cm (2 in) in diameter can be found with fully formed embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s. Most of the cones have been preserved before their seeds could be dispersed. Some cones, however, do not contain embryos and the naked axes of cones have also been recovered (described by Wieland as a separate species - Proaraucaria patagonica). It is believed that A. mirabilis sheds only its seeds but not the scales at maturity. Nevertheless, no separate petrified seeds or bracts have been recovered.
Small woody corm-like structures have also been found. Initially identified as "seedlings", are now known to be lignotuber
Lignotuber
A lignotuber is a starchy swelling of the root crown possessed by some plants as a protection against destruction of the plant stem by fire. The crown contains buds from which new stems may sprout, and a sufficient store of nutrients to support a period of growth in the absence of...
s.
Paleobiology and paleoecology
A. mirabilis exhibits two characteristics shared only by A. bidwillii of the extant Araucaria species. First is the separate origins of the vascular bundles of the bract and fertile scales; second is the highly vascularized "ligule". They also both have dicotyledonous embryos. On this basis, A. mirabilis is classified as belonging to the section Bunya.However, the seeds of A. bidwillii are much larger, 5 to 6 cm (2 to 2.4 in) long and 2.5 to 3.5 cm (0.984251968503937 to 1.4 in) wide, than the seeds of A. mirabilis. A. bidwillii also exhibits cryptocotylar hypogeal
Hypogeal
Hypogeal means "underground".* In botany, a seed is described as hypogeal when the cotyledons of the germinating seed remain non-photosynthetic, inside the seed shell, and below ground...
germination
Germination
Germination is the process in which a plant or fungus emerges from a seed or spore, respectively, and begins growth. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. However the growth of a sporeling from a spore, for example the...
(the cotyledon
Cotyledon
A cotyledon , is a significant part of the embryo within the seed of a plant. Upon germination, the cotyledon may become the embryonic first leaves of a seedling. The number of cotyledons present is one characteristic used by botanists to classify the flowering plants...
s are non-photosynthetic and remain in the shell on germination), while there is evidence that indicates that A. mirabilis and other extinct members of the section Bunya exhibited epigeal
Epigeal
Epigeal, epigean, epigeic and epigeous are biological terms describing an organism's activity above the soil surface.In botany, a seed is described as epigeal when the cotyledons of the germinating seed expand, throw off the seed shell and become photosynthetic above the ground...
germination (the cotyledons are photosynthetic and expand above-ground). In addition, no reliably identifiable fossils of members of the section Bunya have been recovered from Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, the native range of A. bidwillii. The only existing species of Araucaria in South America today are Araucaria angustifolia
Araucaria angustifolia
Araucaria angustifolia, the Paraná pine or Brazilian pine , is a species in the conifer genus Araucaria. Covering an original area of 233000 km², it is native to southern Brazil Araucaria angustifolia, the Paraná pine or Brazilian pine , is a species in the conifer genus Araucaria. Covering an...
and Araucaria araucana
Araucaria araucana
Araucaria araucana is an evergreen tree growing to tall with a trunk diameter. The tree is native to central and southern Chile, western Argentina and south Brazil. Araucaria araucana is the hardiest species in the conifer genus Araucaria...
. Both belong to the section Araucaria of the genus. Setoguchi et al. (1998) have recommended that the extinct members of the section Bunya (which includes Araucaria sphaerocarpa of the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
) be treated as a separate group.
A. mirabilis is found in association with other conifers, including Pararaucaria patagonica (not to be confused with the synonym
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
Proaraucaria patagonica of A. mirabilis), and Araucarites sanctaecrucis
Araucarites sanctaecrucis
Araucarites sanctaecrucis is an extinct coniferous tree from Patagonia, Argentina. Its exact affinities are unknown and it is currently assigned to the form genus Araucarites of the family Araucariaceae. A. sanctaecrucis are known from petrified fossils of branches, foliage, and cones from the...
. P. patagonica is also known from cones. It has no living descendants and its closest living relatives appear to be members of the modern family Cupressaceae
Cupressaceae
The Cupressaceae or cypress family is a conifer family with worldwide distribution. The family includes 27 to 30 genera , which include the junipers and redwoods, with about 130-140 species in total. They are monoecious, subdioecious or dioecious trees and shrubs from 1-116 m tall...
(cypresses). A. sanctaecrucis fossils consist of foliage and branches.
The fossils of the putative bracket fungus
Bracket fungus
Bracket fungi, or shelf fungi, among many groups of the fungi in the phylum Basidiomycota. Characteristically, they produce shelf- or bracket-shaped fruiting bodies called conks that lie in a close planar grouping of separate or interconnected horizontal rows...
Phellinites digiustoi are also found in the Cerro Cuadrado Petrified Forest. The latter was initially believed to be the oldest known mushroom-forming fungi (Agaricomycetes
Agaricomycetes
Agaricomycetes is a class of fungi. The taxon is roughly identical to that defined for the Homobasidiomycetes by Hibbett & Thorn, with the inclusion of Auriculariales and Sebacinales. It includes not only mushrooms but also most species placed in the deprecated taxa Gasteromycetes and...
). Later examinations now make it likely that P. digiustoi was, in fact, part of the periderm of the fossilized bark
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...
of A. mirabilis.
It is also believed that the long necks of sauropod dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
s may have evolved specifically for browsing the foliage of the typically very tall A. mirabilis and other Araucaria trees. Araucaria leaves required long digestion times and were low in protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
, but they were very energy-rich. This and the global distribution of vast forests of Araucaria makes it likely that they were the primary food sources for adult sauropods during the Jurassic. Juveniles, however, which lacked the bulk of the adults and required larger amounts of proteins for growth, probably subsisted on other plants.
A. mirabilis fossils have been found with damage resulting from beetle larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e. These beetles are believed to be the ancestors of the most ancient lineage of bark beetle
Bark beetle
A bark beetle is one of approximately 220 genera with 6,000 species of beetles in the subfamily Scolytinae. Traditionally, this was considered a distinct family Scolytidae, but now it is understood that bark beetles are in fact very specialized members of the "true weevil" family...
s in the weevil
Weevil
A weevil is any beetle from the Curculionoidea superfamily. They are usually small, less than , and herbivorous. There are over 60,000 species in several families, mostly in the family Curculionidae...
family (Curculionidae
Curculionidae
Curculionidae is the family of the "true" weevils . It was formerly recognized in 1998 as the largest of any animal family, with over 40,000 species described worldwide at that time...
) - the members of the tribe
Tribe (biology)
In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...
Tomicini
Tomicini
Tomicini are a tribe of bark beetles, highly specialized weevils of the subfamily Scolytinae. They belong to the group of tribes around the Hylesinini, which are all included in these by some authors...
, which are still serious pest
Pest
Pest may refer to:*Pest , an animal or plant detrimental to humans or human concerns*Pest, an archaic term for pestilence, originally the Black Death*Pest , an ice hockey player specialising in aggravating opponents...
s of conifers today. They were probably host-specific
Host (biology)
In biology, a host is an organism that harbors a parasite, or a mutual or commensal symbiont, typically providing nourishment and shelter. In botany, a host plant is one that supplies food resources and substrate for certain insects or other fauna...
to members of the genus Araucaria since the Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
. Modern A. bidwillii are also hosts to primitive weevils from the family Megalopodidae
Megalopodidae
The Megalopodidae are a small family of leaf beetles, previously included as a subfamily within the Chrysomelidae. One of its constituent subfamilies, Zeugophorinae, which contains a single genus, has also frequently been treated as a subfamily within Chrysomelidae...
and leaf beetle
Leaf beetle
Beetles in the family Chrysomelidae are commonly known as leaf beetles. This is a family of over 35,000 species in more than 2,500 genera, one of the largest and most commonly encountered of all beetle families....
s from the family Nemonychidae
Nemonychidae
Nemonychidae is a small family of weevils, placed within the primitive weevil group because they have straight rather than elbowed antennae. They are often called pine flower weevils. As in the Anthribidae, the labrum appears as a separate segment to the clypeus, and the maxillary palps are long...
.
Distribution and geologic time range
La Matilde Formation
La Matilde Formation is a Jurassic geological formation in Patagonia, Argentina. It is dated to the Middle to Upper Jurassic. From the Bathonian age to the Kimmeridgian age at the latest...
, dated to the Bathonian
Bathonian
In the geologic timescale the Bathonian is an age or stage of the Middle Jurassic. It lasted from approximately 167.7 Ma to around 164.7 Ma...
to Oxfordian ages (164.7 to 155.7 million years ago) of the Middle
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from 176-161 million years ago. In European lithostratigraphy, rocks of this Middle Jurassic age are called the Dogger....
to Upper Jurassic. The area was once part of the subtropical and temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
regions of the southern supercontinent
Supercontinent
In geology, a supercontinent is a landmass comprising more than one continental core, or craton. The assembly of cratons and accreted terranes that form Eurasia qualifies as a supercontinent today.-History:...
Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...
in the Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
era, a more or less continuous landmass consisting of what is now modern South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, Antarctica, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, and New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
.
See also
- List of extinct plants
- PaleobotanyPaleobotanyPaleobotany, also spelled as palaeobotany , is the branch of paleontology or paleobiology dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments , and both the evolutionary history of plants, with a...
- Araucarioxylon arizonicumAraucarioxylon arizonicumAraucarioxylon arizonicum is an extinct species of conifer that is the state fossil of Arizona. The species is known from massive tree trunks that weather out of the Chinle Formation in desert badlands of northern Arizona and adjacent New Mexico, most notably in the Petrified Forest National Park...
- NothofagusNothofagusNothofagus, also known as the southern beeches, is a genus of 35 species of trees and shrubs native to the temperate oceanic to tropical Southern Hemisphere in southern South America and Australasia...