Archaeamphora longicervia

Taxobox
fossil_range = Early Cretaceous

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image_caption = Artist's restoration of
"Archaeamphora longicervia".
image_width = 200px
regnum = Plantae
divisio = Magnoliophyta
classis = Magnoliopsida
ordo = Ericales
familia = ?Sarraceniaceae
genus = "Archaeamphora"
species = "A. longicervia"
binomial = "Archaeamphora longicervia"
binomial_authority = Li (2005)

"Archaeamphora longicervia" is an extinct species of pitcher plant bearing close affinities to extant members of the family Sarraceniaceae. Fossil material assigned to this taxon originates from the Early Cretaceous Yixian Formation in northeastern China.Li, H. 2005. PDFlink| [http://faculty.frostburg.edu/biol/hli/research/Archaeamphora.pdf Early Cretaceous sarraceniacean-like pitcher plants from China.] |2.84 MiB "Acta Bot. Gallica" 152(2): 227-234.]

"A. longicervia" is the earliest known carnivorous plant and represents the only fossil record of pitcher plants. Furthermore, the monotypic "Archaeamphora" is one of the three oldest known genera of angiosperms (flowering plants). Li (2005) notes that "the existence of a so highly derived Angiosperm in the Early Cretaceous suggests that Angiosperms should have originated much earlier, maybe back to 280 mya as the molecular clock studies suggested".

Etymology

The generic name "Archaeamphora" is derived from the Greek: αρχαίος, archaios, combining form in Latin archae- and the Greek "amphoreus" ("pitcher"). The specific epithet "longicervia" is derived from the Latin "longus" ("long") and "cervicarius" ("with a neck"). The latter refers to the characteristic constriction in the pitchers of this species.

Fossil material

All known fossil material of "A. longicervia" originates from the Jianshangou Formation in Beipiao, western Liaoning, China. These Early Cretaceous beds constitute the lower part of the Yixian Formation, [Sun, G., S.-L. Zheng, D.L. Dilcher, Y.D. Wang & S.W Mei 2001. "Early Angiosperms and their Associated Plants from Western Liaoning, China". Shanghai Scientific and Technological Education Publishing House, 227 pp.] [Sun G., D.L. Dilcher, S.-L. Zheng & Z.-K. Zhou 1998. PDFlink| [http://ephedra.hip.uni-heidelberg.de/lehre/ZV-Literatur.pdf In Search of the First Flower: A Jurassic Angiosperm, "Archaefructus", from Northeast China.] |8.76 MiB "Science" 282: 1692-1695.] which is dated at 124.6 million years old. [Swisher III, C.C., Y-Q. Wang, X.-L. Wang, X. Xu & Y. Wang 1999. Cretaceous age for the feathered dinosaurs of Liaoning, China. "Nature" 400: 58-61.] Nine specimens of "A. longicervia" have been found, including holotype CBO0220 and paratype CBO0754.

Description

"A. longicervia" was a herbaceous plant growing to around 5 cm in height. The stem, at least 21 mm long and 1.2 mm wide, bore distinctive vertical ridges and grooves. Pitchers were ascidiate in form and 30 to 40 mm long. Mature pitchers and underdeveloped pitchers or phyllodia-like leaves were arranged spirally around the stem. Pitchers consisted of a tubular base, expanded middle section, constriction around the mouth, and a vertical, spoon-shaped lid. A single wing ran down the adaxial side of each pitcher. Three to five parallel major veins were present on the pitchers, along with a few intercostal veins and numerous small veinlets.

Two unusual bag-like structures were present on each pitcher, one on either side of the central wing. Similar but semi-circular structures were found on the margin of the lid. These structures exhibited strong yellow-green intrinsic fluorescence when exposed to 500 nm wavelength light.

Tiny glands, approximately 4 µm in diameter, were found on the inner surface of the pitchers and partially embedded in the grooves along the veins. These also showed very strong golden-yellow fluorescence.

A single seed was found intimately associated with the fossil material of "A. longicervia" and is presumed to belong to the same species. It is winged and reticulate-tuberculate in morphology, closely resembling the seeds of Sarraceniaceae taxa. The seed is oval-shaped, covered withblack-brown warts, and measures 0.9 mm by 1.25 mm.

Taxonomy

The fossil material of "A. longicervia" was subjected to chemical analysis for oleanane, considered a key marker differentiating angiosperms from gymnosperms. [Moldowan, J.M., J. Dahl, B.J. Huizinga, F.J. Fago, L.J. Hickey, T.M. Peakman & O.W. Taylor 1994. [http://www.sciencemag.org/cgi/content/abstract/265/5173/768 The molecular fossil record of oleanane and its relationship to Angiosperms.] "Science" 265: 768-771.] Oleanane was detected in the pitcher plant specimens, suggesting that they belong to the angiosperms.

Several morphological features of "A. longicervia" suggest a close relationship to Sarraceniaceae. Both taxa exhibit one or two pitcher wings, a smooth peristome, and pitchers that extend vertically from the top of a short petiole.

Li (2005) suggests that "A. longicervia" is morphologically similar to modern "Sarracenia purpurea". It shares with this species the spiral arrangement of its pitchers and phyllodia-like tubular leaves with parallel major veins. "A. longicervia" also shows close affinity to species of the genus "Heliamphora" in having pitchers with a long neck and upright lid. Of particular note is the similarity between the thick semi-circular structures on the lid of "A. longicervia" and the large nectar-secreting "spoon" present on the upper posterior portion of "Heliamphora exappendiculata" pitchers.

Li (2005) mentions the discovery of another type of pitcher plant from the same formation. This variety differs from the type material of "A. longicervia" in having pitchers that lack any constriction before the mouth, instead gradually expanding from the petiole into a hollow trumpet-like shape. He suggests that it "should be a different species" from "A. longicervia". An intermediate form with a wider neck is also reported, suggesting that pitcher plants were already a diversified group in the Early Cretaceous.

Habitat

The area inhabited by "A. longicervia" is thought to have experienced significant climatic fluctuations during the Early Cretaceous, ranging from arid or semi-arid to more humid conditions. [Barrett, P.M. & J. M. Hilton 2006. PDFlink| [http://www.blackwell-synergy.com/doi/pdf/10.1111/j.1749-4877.2006.00006.x The Jehol Biota (Lower Cretaceous, China): new discoveries and future prospects.] "Integrative Zoology" 1: 15-17.] The substrate in the region was mostly composed of lacustrine sediments and volcanic rocks. [Tan, J.-J. & D. Ren 2006. PDFlink| [http://fossilinsects.net/pdfs/Tan_Ren_2006.pdf "Ovatucupes": A New Cupedid Genus (Coleoptera: Archostemata: Cupedidae) From The Jehol Biota (Late Jurassic) Of Western Liaoning, China.] |236 KiB "Entomological News" 117(2): 223-232.]

References

* [http://faculty.frostburg.edu/biol/hli/research/Pitcher/SIGuide.htm Supplementary Information 1]
* [http://faculty.frostburg.edu/biol/hli/research/Pitcher/Fig-SupplementaryMateral.htm Supplementary Information 2]