Shirleya

Last updated

Shirleya
Temporal range: Middle Miocene
O
S
D
C
P
T
J
K
Pg
N
Shirleya grahamae fruit, UWBM 55134 Pigg & Wehr 2002 Plt3 fig31.png
Shirleya grahamae fruit
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Myrtales
Family: Lythraceae
Genus: Shirleya
Pigg & DeVore
Species:
S. grahamae
Binomial name
Shirleya grahamae
Pigg & DeVore

Shirleya is an extinct genus in the crape myrtle family, Lythraceae, which contains a single species, Shirleya grahamae. The genus and species are known from Middle Miocene fossils found in Central Washington.

Contents

History and classification

The species was first described from specimens of silicified fruits preserved in chert of the "Yakima Canyon Flora". [1] The chert was recovered from the type locality "Hi hole" site, one of the "county line hole" fossil localities of the "Yakima Canyon Flora" located north of Interstate 82 in Yakima County, Washington. [2] [1] The "Hi hole" site works strata was formerly thought to be part of the Museum Flow Package within the interbeds of the Sentinel Bluffs Unit of the central Columbia Plateau N2 Grande Ronde Basalt, Columbia River Basalt Group. The Museum Flow Package interbeds are dated to the middle Miocene and are approximately 15.6 million years old. [3] Later re-evaluation of the "Hi hole" site indicated that the site is included into a basalt flow, having deposited into pockets and crevasses on the surface of the flow, rather than being part of the interbedded Museum flow package. [1] The evaluation suggested the basalt is part of the Wanapum Basalt and that the fossils are possibly a little younger than formerly reported. [2] [1] Dating reported in 2007 of a related site near Ellensburg, Washington confirmed that the deposits worked are pockets within the basalt flows, and the 15.6 million year old date was accurate. [4]

At the time of study, the holotype fruit, specimen UWBM 55134, and a series of paratype specimens were preserved in the Burke Museum of Natural History and Culture while additional paratypes, and examined fossils that were not part of the type series, were part of the paleobotanical collections at Arizona State University. The specimens represent a range of preservation conditions, ranging from exposed on weathered surfaces of the chert, totally weathered out of the chert, and as fully enclosed fruits in chert. A total of over 24 specimens in or preserved by chert were studied by paleobotanists Kathleen Pigg and Melanie DeVore, with their 2005 type description being published in the American Journal of Botany . Pigg and DeVore coined the genus name Shirleya and the specific epithet grahamae as a matronym honoring Shirley A. Graham, then of the Missouri Botanical Garden in St. Louis, Missouri for her work and "significant contributions" to the family Lythraceae. [1]

Based on similarities to the living genus Lagerstroemia , Pigg and DeVore placed Shirleya into Lythraceae, with no indication of a subfamily assignment. While Shirleya has a number of features that are similar to Lagerstroemia, there are also several distinct features. The fruits have a thicker pericarp that is similar to the genera Duabanga and Sonneratia which have berry-like fruits, but Shirleya fruits were dehiscent, unlike the berry-like fruits, as indicated by several isolated silicified fruit valves. The seeds in Shirleya fruits develop near the tops of the fruit gynoecium with wings extending down towards the gynoecium base, while in Lagerstroemia the seeds develop in reverse position, with the wing extending from the seed towards the top of the gynoecium. [1] These differences lead Pigg and DeVore to place the fossils in a new genus. [1]

Description

The fruits of Shirleya range up to 10.0 mm (0.39 in) long and have a diameter of up to 12.5 mm (0.49 in) giving a subglobose outline. The central axis of the fruit is mostly a parenchymatous pith that forms a star shape. The fruits have between five and seven wedge shaped locules or minute chambers surrounding the central axis and narrow dehiscence slits which split on maturity, breaking the fruit into sections of two locule halves and the joining septum. [1] Each locule contains between five and seven mature seeds plus occasional smaller seeds. [1] The seeds are tightly packed into each locule and hang down from the apical area of the locule with wings curving out from the axis. The seeds are up to 4.6 mm (0.18 in) in length with a tail or hook on both the proximal and distal ends, and a wing that make up approximately two-thirds of the seed length. The seed wings each have a central bilobed parenchymatous mass that surrounds a central cavity. [1]

Related Research Articles

<span class="mw-page-title-main">Lythraceae</span> Family of flowering plants

Lythraceae is a family of flowering plants, including 32 genera, with about 620 species of herbs, shrubs, and trees. The larger genera include Cuphea, Lagerstroemia (56), Nesaea (50), Rotala (45), and Lythrum (35). It also includes the pomegranate and the water caltrop. Lythraceae has a worldwide distribution, with most species in the tropics, but ranging into temperate climate regions as well.

Wessiea is an extinct morphogenus of fern not placed in a specific family. Wessiea is known from Late Cretaceous and Middle Miocene age fossils found in Central Washington USA and Southern Alberta Canada. Two species are described in the morphogenus, W. oroszii and the type species W. yakimaensis.

Carya washingtonensis is an extinct species of hickory nut in the walnut family Juglandaceae. The species is solely known from the Miocene sediments exposed in Kittitas County near Ellensburg, Washington.

Osmunda wehrii is an extinct species of fern in the modern genus Osmunda of the family Osmundaceae. Osmunda wehrii is known from Langhian age Miocene fossils found in Central Washington.

<span class="mw-page-title-main">Princeton Chert</span> Fossilized Flora

The Princeton Chert is a fossil locality in British Columbia, Canada, which comprises an anatomically preserved flora of Eocene Epoch age, with rich species abundance and diversity. It is located in exposures of the Allenby Formation on the east bank of the Similkameen River, 8.5 km (5.3 mi) south of the town of Princeton, British Columbia.

<span class="mw-page-title-main">Allenby Formation</span>

The Allenby formation is a sedimentary rock formation in British Columbia which was deposited during the Ypresian stage of the Early Eocene. It consists of conglomerates, sandstones with interbedded shales and coal. The shales contain an abundance of insect, fish and plant fossils known from 1877 and onward, while the Princeton Chert was first indented in the 1950's and is known from anatomically preserved plants.

Kardiasperma is an extinct genus of flowering plants in the hazelnut family, Betulaceae, containing the single species Kardiasperma parvum. The species is solely known from the middle Eocene sediments exposed in north central Oregon and was first described from a series of isolated fossil nuts in cherts.

<i>Liquidambar changii</i> Extinct species of flowering plant

Liquidambar changii is an extinct species of sweetgum in the Altingiaceae genus Liquidambar. Liquidambar changii is known from Middle Miocene fossils found in Central Washington.

<i>Quercus hiholensis</i> Extinct species of oak

Quercus hiholensis is an extinct species of oak in the Fagaceae genus Quercus. The species is known from Middle Miocene fossils found in Central Washington.

Nyssa spatulata is an extinct species of flowering plant in the tupelo family, Nyssaceae known from the middle Eocene sediments exposed in north central Oregon. The species was first described from a series of isolated fossil seeds in chert.

<i>Nuphar carlquistii</i> Extinct species of flowering plant

Nuphar carlquistii is an extinct species of flowering plant in the family Nymphaeaceae related to the modern spatterdock, Nuphar advena. The species is known from fossil seeds and fruits found in the early Eocene Okanagan Highlands deposits of northern Washington state and British Columbia, Canada.

Concavistylon is an extinct genus of flowering plant in the family Trochodendraceae comprising a single species Concavistylon kvacekii. The genus is known from fossils found in Middle Miocene deposits of central Oregon. A second species "Concavistylon" wehrii was originally placed in Concavistylon, but subsequently moved to a new genus Paraconcavistylon in 2020.

<i>Tetracentron hopkinsii</i> Extinct species of flowering plant

Tetracentron hopkinsii is an extinct species of flowering plant in the family Trochodendraceae. The species is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States and south Central British Columbia. The species was first described from fossil leaves found in the Allenby Formation. T. hopkinsii are possibly the leaves belonging to the extinct trochodendraceous fruits Pentacentron sternhartae.

Trochodendron postnastae is an extinct species of flowering plant in the family Trochodendraceae. The species is known from fossils found in Middle Miocene deposits of central Oregon. T. postnastae are possibly the leaves belonging to the extinct trochodendraceous fruits Trochodendron rosayi.

Trochodendron rosayi is an extinct species of flowering plant in the family Trochodendraceae. The species is known from fossils found in Middle Miocene deposits of central Oregon. T. rosayi are possibly the fruits belonging to the extinct trochodendraceous leaf species Trochodendron postnastae.

The paleoflora of the Eocene Okanagan Highlands includes all plant and fungi fossils preserved in the Eocene Okanagan Highlands Lagerstätten. The highlands are a series of Early Eocene geological formations which span an 1,000 km (620 mi) transect of British Columbia, Canada and Washington state, United States and are known for the diverse and detailed plant fossils which represent an upland temperate ecosystem immediately after the Paleocene-Eocene thermal maximum, and before the increased cooling of the middle and late Eocene to Oligocene. The fossiliferous deposits of the region were noted as early as 1873, with small amounts of systematic work happening in the 1880-90s on British Columbian sites, and 1920-30s for Washington sites. A returned focus and more detailed descriptive work on the Okanagan Highlands sites revived in the 1970's. The noted richness of agricultural plant families in Republic and Princeton floras resulted in the term "Eocene orchards" being used for the paleofloras.

<i>Ulmus chuchuanus</i> Extinct species of elm

Ulmus chuchuanus is an extinct species of flowering plant in the family Ulmaceae related to the modern elms. The species is known from fossil leaves and fruits found in early Eocene sites of northern Washington state, United States and central British Columbia, Canada.

The Paleobiota of the Klondike Mountain Formation comprises a diverse suite of Early Eocene plants and animals recovered from North Central Washington State. The formation outcrops in locations across the north western area of Ferry County, with major sites in Republic, north west of Curlew Lake, and on the Toroda Creek area. The formation is the southern most of the Eocene Okanagan Highlands, sharing much of the paleoflora and paleofauna with site across Central and southern British Columbia.

References

  1. 1 2 3 4 5 6 7 8 9 10 Pigg, K. B.; DeVore, M. L. (2005). "Shirleya grahamae gen. et sp. nov.(Lythraceae), Lagerstroemia-like fruits from the middle Miocene Yakima Canyon flora, central Washington State, USA". American Journal of Botany. 92 (2): 242–251. doi:10.3732/ajb.92.2.242. PMID   21652401.[ permanent dead link ]
  2. 1 2 Pigg, K. B.; Ickert-Bond, S. M.; Wen, J. (2004). "Anatomically preserved Liquidambar (Altingiaceae) from the middle Miocene of Yakima Canyon, Washington state, USA, and its biogeographic implications". American Journal of Botany. 91 (3): 499–509. doi:10.3732/ajb.91.3.499. PMID   21653405.
  3. Pigg, K.B. (2001). "Anatomically preserved Woodwardia virginica (Blechnaceae) and a new Filicalean fern from the Middle Miocene Yakima Canyon Flora of central Washington, USA". American Journal of Botany. 88 (5): 777–787. doi:10.2307/2657030. JSTOR   2657030. PMID   11353703.
  4. Pigg, K. B.; DeVore, M. D.; Benedict, J. C.; Creekmore, R. M. (2014). "Fruits of Melia (Meliaceae, Melioideae) from the Middle Miocene Yakima Canyon Flora of Central Washington State, USA". Paleobotany and Biogeography: A Festschrift for Alan Graham in His 80th Year: 326–337.