Dillhoffia
Encyclopedia
Dillhoffia is an extinct
monotypic
genus of flowering plant
with a single species, Dillhoffia cachensis known from Ypresian
age Eocene
fossil
s found in British Columbia, Canada, and Washington
, USA. The genus and species were described from fifteen specimens found in an unnamed formation belonging to the Kamloops group; and two specimens from the Klondike Mountain Formation. The unnamed formation outcrops at the McAbee fossil site near Cache Creek, BC
, which is designated the type locality
while the two U.S. specimens were recovered from the Tom Thumb Tuff member of the Klondike Mountain Formation in Republic, Washington
. It is of interest to note that of the Okanagan highlands fossil sites Dillhoffia is only known from two locations, and is absent or has not been identified from the others.
The holotype
specimen, number TMP 83.39.175, is preserved in the Royal Tyrell Museum and the paratype
specimens are in the Thompson Rivers University
and University of Saskatchewan
collections. The specimens were studied by paleobotanists Steven Manchester of the University of Florida
and Kathleen Pigg of Arizona State University
. Manchester and Pigg published the 2008 type description for D. cachensis in the journal Botany
, Volume 86, number 9. They chose the generic name
Dillhoffia to honor the brothers Richard M. Dillhoff and Thomas A. Dillhoff for their substantial contributions and promotion of Pacific Northwest North American Paleogene
floras. The specific name
is a reference to Cache Creek, British Columbia, the nearest town to the McAbee site.
Dillhoffia is known from infructescence
s only. The infructescences are pedunculate
having a globose head which bore at least twelve flowers and has been preserved as fossils with several sessile fruits. The fruits are elongate to ellipsoidal in form, being 8–10 mm (0.31496062992126–0.393700787401575 in) by 4–5 mm (0.15748031496063–0.196850393700787 in), and indehiscent
. The enlarged calyx present on the fruits is thought to have been used for wind transport, with the calyx being dish to funnel shaped and born approximately three-quarters of the way up the fruit from the base. Formed from a persistent paranth, the calyx may have been accrescent, as small-sized calyces are known. It is unknown what the petals and stamens looked like, as none have been found, possibly being shed during fruit formation. Dillhoffia was most likely a non-magnoliid angiosperm as indicated by is inferior ovary, but placement into a specific family is not possible with the fossils known.
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
genus of flowering plant
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
with a single species, Dillhoffia cachensis known from 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....
age 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...
fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s found in British Columbia, Canada, and Washington
Washington State
Washington State may refer to:* Washington , often referred to as "Washington state" to differentiate it from Washington, D.C., the capital of the United States* Washington State University, a land-grant college in that state- See also :...
, USA. The genus and species were described from fifteen specimens found in an unnamed formation belonging to the Kamloops group; and two specimens from the Klondike Mountain Formation. The unnamed formation outcrops at the McAbee fossil site near Cache Creek, BC
Cache Creek, British Columbia
Cache Creek is a junction community northeast of Vancouver in British Columbia, Canada. It is on the Trans-Canada Highway in the province of British Columbia at its junction with northbound Highway 97...
, which is designated the type locality
Type locality (geology)
Type locality , also called type area or type locale, is the where a particular rock type, stratigraphic unit, fossil or mineral species is first identified....
while the two U.S. specimens were recovered from the Tom Thumb Tuff member of the Klondike Mountain Formation in Republic, Washington
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:...
. It is of interest to note that of the Okanagan highlands fossil sites Dillhoffia is only known from two locations, and is absent or has not been identified from the others.
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 TMP 83.39.175, is preserved in the Royal Tyrell Museum and the 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 in the Thompson Rivers University
Thompson Rivers University
Thompson Rivers University is a comprehensive university located in Kamloops, British Columbia, Canada. It offers students a broad range of courses, career streams, and the ability to ladder credits from diploma programs into full degrees...
and University of Saskatchewan
University of Saskatchewan
The University of Saskatchewan is a Canadian public research university, founded in 1907, and located on the east side of the South Saskatchewan River in Saskatoon, Saskatchewan, Canada. An "Act to establish and incorporate a University for the Province of Saskatchewan" was passed by the...
collections. The specimens were studied by paleobotanists Steven Manchester of the University of Florida
University of Florida
The University of Florida is an American public land-grant, sea-grant, and space-grant research university located on a campus in Gainesville, Florida. The university traces its historical origins to 1853, and has operated continuously on its present Gainesville campus since September 1906...
and Kathleen Pigg of Arizona State University
Arizona State University
Arizona State University is a public research university located in the Phoenix Metropolitan Area of the State of Arizona...
. Manchester and Pigg published the 2008 type description for D. cachensis in the journal Botany
Botany (journal)
Botany is a monthly peer-reviewed scientific journal that has been published since 1929 by NRC Research Press. It features research articles and notes in all segments of botany...
, Volume 86, number 9. They chose the generic name
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...
Dillhoffia to honor the brothers Richard M. Dillhoff and Thomas A. Dillhoff for their substantial contributions and promotion of Pacific Northwest North American Paleogene
Paleogene
The Paleogene is a geologic period and system that began 65.5 ± 0.3 and ended 23.03 ± 0.05 million years ago and comprises the first part of the Cenozoic Era...
floras. The specific name
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...
is a reference to Cache Creek, British Columbia, the nearest town to the McAbee site.
Dillhoffia is known from infructescence
Infructescence
Infructescence is defined as the ensemble of fruits derived from ovaries of an inflorescence, structured according to the inflorescence scheme....
s only. The infructescences are pedunculate
Peduncle (botany)
In botany, a peduncle is a stem supporting an inflorescence, or after fecundation, an infructescence.The peduncle is a stem, usually green and without leaves, though sometimes colored or supporting small leaves...
having a globose head which bore at least twelve flowers and has been preserved as fossils with several sessile fruits. The fruits are elongate to ellipsoidal in form, being 8–10 mm (0.31496062992126–0.393700787401575 in) by 4–5 mm (0.15748031496063–0.196850393700787 in), and indehiscent
Dehiscence (botany)
Dehiscence is the opening, at maturity, in a pre-defined way, of a plant structure, such as a fruit, anther, or sporangium, to release its contents. Sometimes this involves the complete detachment of a part. Structures that open in this way are said to be dehiscent...
. The enlarged calyx present on the fruits is thought to have been used for wind transport, with the calyx being dish to funnel shaped and born approximately three-quarters of the way up the fruit from the base. Formed from a persistent paranth, the calyx may have been accrescent, as small-sized calyces are known. It is unknown what the petals and stamens looked like, as none have been found, possibly being shed during fruit formation. Dillhoffia was most likely a non-magnoliid angiosperm as indicated by is inferior ovary, but placement into a specific family is not possible with the fossils known.