Abies milleri
Encyclopedia
Abies milleri, an extinct species of fir
known from fossil
remains found in deposits from the early Eocene
Ypresian
stage (around 49.5 mya) in Washington State, USA, is the oldest confirmed record for the fir
genus. The species was described from 81 fossil specimens collected from Burke Museum
site number A0307 in Ferry County, Washington. The holotype
specimen, number # UWBM 31299, and the eleven paratype
specimens are currently deposited in the collections of the Burke Museum in Seattle, where they were studied and described by Howard E. Schorn and Wesley C. Wehr. Schorn and Wehr published their 1986 type description for A. milleri in the Burke Museum Contributions in Anthropology and Natural History
, Volume 1. The specific epithet, milleri, was coined in honor of Charles N. Miller Jr for his contributions to the study and understanding of the conifer family Pinaceae
. The studied specimens were excavated from the Tom Thumb Tuff member of the Klondike Mountain Formation
in the city of Republic
.
A. milleri has been placed in the Fir
genus Abies, which has between 48 and 55 species native to much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range. The characters used to separate extant species of Abies are based on the reproductive structures such as cone scales
, wing seeds
and bracts. The placement in Abies is based on the dorso-ventrally flattened leaves, and the circular leaf scars, which separate the organs from those of Pseudotsuga and Keteleeria
. Within Abies, A. milleri shows similarities with A. kawakamii
and A. chensiensis
from Asia and with A. concolor and A. lasiocarpa of North America. A. milleri does not show traits which allow placement in any one of Abies genus sections, however.
The 81 specimens studied for the A. milleri description included 40 cone scales, 21 wing seeds, 10 foliated axes, and two detached needles. Schorn and Wehr placed the different detached organ fossils in the same species based on a number of factors. Where visible, all the cone scales have bracts and are morphologically similar. The scales display impressions on the admedial surface of wing seeds that match the fossil seed dimensions. The needle arrangement is consistent on both foliated and defoliated axes, with attached needles matching isolated needles. All of the fossils occurred in the same stratigraphic layers.
The cone scales up to 32 by and 1.25-2 times as long as wide, have a generally triangular to cuneate shape with the distal edge turned upwards and the stalk on half the length of the scale. Sometimes preserved with cone scales are the bracts which average 5 by and have a central accuminate flanked by thinner laminae. The wing seeds are up to 27 by and have a pterostegium which covers on average three-quarters of the seed. The narrow obovate seed is generally 12 by, 1-1.5 times the length of the upper wing edge while the wing itself is widest in the distal half. Needles of A. milleri reach up to 38 millimetres (1.5 in) long, but have a width of only 1 millimetre (0.0393700787401575 in) at the base. The leaf base is generally as wide to slightly wider than the leaf and round, with the leaf angled approximately 70 degrees upward from the attachment. Leaf scars on axes are circular to slightly oval, 1.5 by, and show a vascular bundle scar in the center. Oval leaf scars are oriented with the long axis parallel to the length of the stem axis. While the scars show the leaves to be in a helical arrangement, the leaves would have had a flattened orientation on either side of the axis.
Fir
Firs are a genus of 48–55 species of evergreen conifers in the family Pinaceae. They are found through much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range...
known from fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
remains found in deposits from the early Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
Ypresian
Ypresian
In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between and , is preceded by the Thanetian age and is followed by the Eocene Lutetian age....
stage (around 49.5 mya) in Washington State, USA, is the oldest confirmed record for the fir
Fir
Firs are a genus of 48–55 species of evergreen conifers in the family Pinaceae. They are found through much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range...
genus. The species was described from 81 fossil specimens collected from Burke Museum
Burke Museum of Natural History and Culture
The Burke Museum of Natural History and Culture has been a Washington state museum since 1899. It is located at the University of Washington campus at the intersection of N.E. 45th Street and 17th Avenue N.E. in Seattle, Washington, USA, in the University District. It is the only major natural...
site number A0307 in Ferry County, Washington. The holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
specimen, number # UWBM 31299, and the eleven paratype
Paratype
Paratype is a technical term used in the scientific naming of species and other taxa of organisms. The exact meaning of the term paratype when it is used in zoology is not the same as the meaning when it is used in botany...
specimens are currently deposited in the collections of the Burke Museum in Seattle, where they were studied and described by Howard E. Schorn and Wesley C. Wehr. Schorn and Wehr published their 1986 type description for A. milleri in the Burke Museum Contributions in Anthropology and Natural History
Burke Museum of Natural History and Culture
The Burke Museum of Natural History and Culture has been a Washington state museum since 1899. It is located at the University of Washington campus at the intersection of N.E. 45th Street and 17th Avenue N.E. in Seattle, Washington, USA, in the University District. It is the only major natural...
, Volume 1. The specific epithet, milleri, was coined in honor of Charles N. Miller Jr for his contributions to the study and understanding of the conifer family Pinaceae
Pinaceae
Pinaceae are trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, firs, hemlocks, larches, pines and spruces. The family is included in the order Pinales, formerly known as Coniferales. Pinaceae are supported as monophyletic by its protein-type sieve...
. The studied specimens were excavated from the Tom Thumb Tuff member of the Klondike Mountain Formation
Klondike Mountain Formation
The Klondike Mountain Formation is an early Eocene geologic formation that records the sedimentation in the southern most of a string of highland subtropical/Temperate lakes in Washington state and British Columbia. The formation is best known for exceptionally well preserved plant and insect fossils...
in the city of Republic
Republic, Washington
Republic is a city in Ferry County, Washington, United States. The population was 1,073 at the 2010 census, a 12.5% increase over the 2000 Census. It is the county seat of Ferry County.-History:...
.
A. milleri has been placed in the Fir
Fir
Firs are a genus of 48–55 species of evergreen conifers in the family Pinaceae. They are found through much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range...
genus Abies, which has between 48 and 55 species native to much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range. The characters used to separate extant species of Abies are based on the reproductive structures such as cone scales
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...
, wing seeds
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
and bracts. The placement in Abies is based on the dorso-ventrally flattened leaves, and the circular leaf scars, which separate the organs from those of Pseudotsuga and Keteleeria
Keteleeria
Keteleeria is a genus of three species of coniferous trees in the family Pinaceae, related to the genera Nothotsuga and Pseudolarix. It is distinguished from Nothotsuga by the much larger cones, and from Pseudolarix by the evergreen leaves and the cones not disintegrating readily at maturity...
. Within Abies, A. milleri shows similarities with A. kawakamii
Abies kawakamii
Abies kawakamii is a species of conifer in the Pinaceae family.It is found only in Taiwan.-Source:* Conifer Specialist Group 1998. . Downloaded on 10 July 2007....
and A. chensiensis
Abies chensiensis
Abies chensiensis, the Shensi fir, is a fir native to Gansu, Hubei, Sichuan, Tibet, Yunnan in China and Arunachal Pradesh in India. It was first described by Philippe Édouard Léon Van Tieghem in 1892....
from Asia and with A. concolor and A. lasiocarpa of North America. A. milleri does not show traits which allow placement in any one of Abies genus sections, however.
The 81 specimens studied for the A. milleri description included 40 cone scales, 21 wing seeds, 10 foliated axes, and two detached needles. Schorn and Wehr placed the different detached organ fossils in the same species based on a number of factors. Where visible, all the cone scales have bracts and are morphologically similar. The scales display impressions on the admedial surface of wing seeds that match the fossil seed dimensions. The needle arrangement is consistent on both foliated and defoliated axes, with attached needles matching isolated needles. All of the fossils occurred in the same stratigraphic layers.
The cone scales up to 32 by and 1.25-2 times as long as wide, have a generally triangular to cuneate shape with the distal edge turned upwards and the stalk on half the length of the scale. Sometimes preserved with cone scales are the bracts which average 5 by and have a central accuminate flanked by thinner laminae. The wing seeds are up to 27 by and have a pterostegium which covers on average three-quarters of the seed. The narrow obovate seed is generally 12 by, 1-1.5 times the length of the upper wing edge while the wing itself is widest in the distal half. Needles of A. milleri reach up to 38 millimetres (1.5 in) long, but have a width of only 1 millimetre (0.0393700787401575 in) at the base. The leaf base is generally as wide to slightly wider than the leaf and round, with the leaf angled approximately 70 degrees upward from the attachment. Leaf scars on axes are circular to slightly oval, 1.5 by, and show a vascular bundle scar in the center. Oval leaf scars are oriented with the long axis parallel to the length of the stem axis. While the scars show the leaves to be in a helical arrangement, the leaves would have had a flattened orientation on either side of the axis.