Archaeamphora

Archaeamphora longicervia is a disputed fossil plant species attributed extinct species of flowering plants and the only member of the genus Archaeamphora. Fossil material assigned to this taxon originates from the Yixian Formation of northeastern China, dated to the Early Cretaceous (around 145 to 101 million years ago).[1]

Archaeamphora
Temporal range: Early Cretaceous
Artist's reconstruction of Archaeamphora longicervia after Li (2005)[1]
Scientific classification
Kingdom:
Plantae
(unranked):
Angiosperms
(unranked):
?Eudicots
(unranked):
?Asterids
Order:
?Ericales
Family:
?Sarraceniaceae
Genus:
Archaeamphora
Species:
A. longicervia
Binomial name
Archaeamphora longicervia
Li (2005)[1]

The species was originally described as a pitcher plant with close affinities to extant members of the family Sarraceniaceae. This would make it the earliest known carnivorous plant and the only known fossil record of Sarraceniaceae, or the New World pitcher plant family.[2][3][4][5] Archaeamphora is also one of the three oldest known genera of angiosperms (flowering plants). Li (2005) wrote 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".[1]

Subsequent authors have questioned the identification of Archaeamphora as a pitcher plant.[6][7][8]

Etymology

The generic name Archaeamphora is derived from the Greek αρχαίος, archaíos ("ancient"; combining form in Latin: archae-), and ἀμφορεύς, amphoreus ("pitcher"). The specific epithet longicervia is derived from the Latin longus ("long") and cervicarius ("with a neck"), in reference to the characteristic constriction in the pitcher-like structures of this species.[1]

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,[9][10] which is dated at 124.6 million years old.[11] Nine specimens of A. longicervia have been found, including holotype CBO0220 and paratype CBO0754.[1]

Description

Archaeamphora longicervia was a herbaceous plant growing to around 50 mm (2.0 in) in height. The stem, at least 21 mm (0.83 in) long by 1.2 mm (0.047 in) wide, bore distinctive vertical ridges and grooves. The pitcher-like structures were ascidiate in form and 30 to 40 mm (1.2 to 1.6 in) 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.[1]

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 visible light with a wavelength of 500 nm (blue-green).[1]

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.[1]

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 with black-brown warts, and measures 0.9 by 1.25 mm (0.035 by 0.049 in).[1]

Taxonomy

The fossil material of A. longicervia was subjected to chemical analysis for oleanane, considered a key marker differentiating angiosperms from gymnosperms.[12] Oleanane was detected in these specimens, suggesting that they belong to the angiosperms.[1]

Pitcher plant interpretation

According to Li (2005), several morphological features of A. longicervia indicate 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.[1]

Pitchers of Sarracenia purpurea

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. Archaeamphora longicervia also shows a resemblance 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 "bubble" present on the upper posterior portion of Heliamphora exappendiculata[nb 1] pitchers.[1]

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 these plants were already a diversified group in the Early Cretaceous.[1]

Current understanding

Heřmanová & Kvaček (2010) opined that the pitcher plant interpretation of Archaeamphora is "problematic and the fossil is in need of revision".[7]

In their 2011 book, Sarraceniaceae of South America, McPherson et al. summarised current thinking on Archaeamphora as follows:[6]

Serious doubt is emerging that reduces the likelihood that Archaeamphora longicervia belongs in the Sarraceniaceae lineage, or was even a pitcher plant at all. [...] Although Archaeamphora might well be a representative of the earliest flowering plants on Earth [...] it is very unlikely that it represents an ancestor of Sarraceniaceae since it is much too old to be part of the advanced "crown group" of Ericales to which Sarraceniaceae belong. [...] Another contradiction is that except for Archaeamphora, there is no other evidence to suggest that Sarraceniaceae evolved outside the New World, to which all extant members of the family are endemic.

Wong et al. (2015) put forward a new perspective [16] as follows:

Archaeamphora longicervia H. Q. Li was described as an herbaceous, Sarraceniaceae-like pitcher plant from the mid Early Cretaceous Yixian Formation of Liaoning Province, northeastern China. Here, a re-investigation of A. longicervia specimens from the Yixian Formation provides new insights into its identity and the morphology of pitcher plants claimed by Li. We demonstrate that putative pitchers of Archaeamphora are insect-induced leaf galls that consist of three components: (1) an innermost larval chamber; (2) an intermediate zone of nutritive tissue; and (3) an outermost wall of sclerenchyma. Archaeamphora is not a carnivorous, Sarraceniaceae-like angiosperm, but represents insect-galled leaves of the previously reported gymnosperm Liaoningocladus boii G. Sun et al. from the Yixian Formation.

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.[14] The substrate in the region was mostly composed of lacustrine sediments and volcanic rocks.[15]

See also

Notes
  1. This taxon was recognised as a variety of Heliamphora heterodoxa when Archaeamphora was described in 2005.[1] It was raised to species rank the following year.[13]

References
  1. Li, H. 2005. "Early Cretaceous sarraceniacean-like pitcher plants from China" (PDF). Archived from the original (PDF) on 2006-09-02. Retrieved 2007-01-27. Acta Botanica Gallica 152(2): 227-234. (Supplementary Information 1, Supplementary Information 2)
  2. Krutzsch, W (1985). "Über Nepenthes-Pollen im europäischen Tertiär". Gleditschia. 13: 89–93.
  3. Krutzsch, W (1989). "Paleogeography and historical phytogeography (paleochorology) in the Neophyticum". Plant Systematics and Evolution. 162 (1–4): 5–61. doi:10.1007/BF00936909.
  4. Anderson, J.A.R.; Muller, J. (1975). "Palynological study of a Holocene peat and a Miocene coal deposit from NW Borneo". Review of Palaeobotany and Palynology. 19 (4): 291–351. doi:10.1016/0034-6667(75)90049-4.
  5. Kumar, M (1995). "Pollen tetrads from Palaeocene sediments of Meghalaya, India: comments on their morphology, botanical affinity and geological records". Palaeobotanist. 43 (1): 68–81.
  6. McPherson, S., A. Wistuba, A. Fleischmann & J. Nerz 2011. Sarraceniaceae of South America. Redfern Natural History Productions, Poole.
  7. Heřmanová, Z.; Kvaček, J. (2010). "Late Cretaceous Palaeoaldrovanda, not seeds of a carnivorous plant, but eggs of an insect". Journal of the National Museum (Prague), Natural History Series. 179 (9): 105–118. Archived from the original on 2015-10-09. Retrieved 2012-10-26.
  8. Brittnacher, J (2013). "Phylogeny and biogeography of the Sarraceniaceae". Carnivorous Plant Newsletter. 42 (3): 99–106.
  9. 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.
  10. Sun, G.; Dilcher, D.L.; Zheng, S.-L.; Zhou, Z.-K. (1998). "In Search of the First Flower: A Jurassic Angiosperm, Archaefructus, from Northeast China" (PDF). Science. 282 (5394): 1692–1695. doi:10.1126/science.282.5394.1692. PMID 9831557. Archived from the original (PDF) on 2011-07-19.
  11. Swisher, III; Wang, Y-Q.; Wang, X.-L.; Xu, X.; Wang, Y. (1999). "Cretaceous age for the feathered dinosaurs of Liaoning, China". Nature. 400 (6739): 58–61. doi:10.1038/21872.
  12. Moldowan, J.M.; Dahl, J.; Huizinga, B.J.; Fago, F.J.; Hickey, L.J.; Peakman, T.M.; Taylor, O.W. (1994). "The molecular fossil record of oleanane and its relationship to Angiosperms". Science. 265 (5173): 768–771. doi:10.1126/science.265.5173.768. PMID 17736275.
  13. Nerz, J.; Wistuba, A. (2006). "Heliamphora exappendiculata, a clearly distinct species with unique characteristics". Carnivorous Plant Newsletter. 35 (2): 43–51.
  14. Barrett, P.M.; Hilton, J. M. (2006). "The Jehol Biota (Lower Cretaceous, China): new discoveries and future prospects". Integrative Zoology. 1 (1): 15–17. doi:10.1111/j.1749-4877.2006.00006.x. PMID 21395985.
  15. Tan, J.-J.; Ren, D. (2006). "Ovatucupes: A New Cupedid Genus (Coleoptera: Archostemata: Cupedidae) From The Jehol Biota (Late Jurassic) Of Western Liaoning, China" (PDF). Entomological News. 117 (2): 223–232. doi:10.3157/0013-872x(2006)117[223:oancgc]2.0.co;2.

16. Wong, WO; Dilcher, DL; Labandeira, CC; Sun, G; Fleischmann, A (2015). "Early Cretaceous Archaeamphora is not a carnivorous angiosperm". Frontiers in Plant Science. 6: 326. doi:10.3389/fpls.2015.00326. PMC 4423337. PMID 25999978.

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