''Hapsidophyllas'' is a rare

Ediacaran The Ediacaran ( ) is a geological period of the Neoproterozoic geologic era, Era that spans 96 million years from the end of the Cryogenian Period at 635 Million years ago, Mya to the beginning of the Cambrian Period at 538.8 Mya. It is the last ...

rangeomorph The rangeomorphs are a group of Ediacaran Ediacaran biota, fossils. Ediacarans are the oldest large fossil organisms on earth, and many are not self-evidently related to anything else that has ever lived. However, some Ediacarans clearly resemble ...

fossil found at Mistaken Point,

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. It was first identified by Emily Bamforth and Guy Narbonne in 2009. Because its characteristic flexible leaflet structure is dissimilar to other known rangeomorphs, Bamforth and Narbonne describe it as a new rangeomorph form, called hapsidophyllid. The only other known hapsidophyllid is the Ediacaran frond '' Frondophyllas grandis'', which shares the network-like configuration of leaflets seen in ''Hapsidophyllas''. Currently, the ''Hapsidophyllas flexibilis'' holotype resides in its type locality in the Mistaken Point Ecological Reserve, and a cast of the specimen is on display at the Royal Ontario Museum in Toronto, Canada.

Etymology

The generic name roughly translates to 'A network of leaves', from the Greek words ''hapsis'', to mean 'network' or 'mesh', and ''phyllon'', to mean 'leaves'.

Description

The ''Hapsidophyllas flexibilis'' holotype is 110 mm long and 4 mm wide. It is composed of multibranched leaflets radiating from a single elongate basal rod. The leaflets gradually taper toward their distal ends and overlap one another. This leaf shape points towards a suspension feeding behavior. The overlapping branches of ''Hapsidophyllas'' are architecturally similar to the renowned Ediacaran frond '' Charnia''. However, a significant difference between the two is that the primary branches of ''Charnia'' are connected to a central tube that is absent or internal, while hapsidophyllid leaflets are attached to a visible stalk.

Paleoecology

Sedimentary studies show that Mistaken Point organisms, including ''Hapsidophyllas'', lived on the deep seafloor below the

photic zone The photic zone (or euphotic zone, epipelagic zone, or sunlight zone) is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological ...

. Because Mistaken Point organisms were preserved under deposit layers of volcanic ash, their proximity to the seafloor can be estimated based on the quality of their preservation. Due to its excellent preservation, it is estimated that the ''Hapsidophyllas flexibilis'' laid semi-prone to the seafloor in its life.

References

{{Taxonbar, from1=Q111398064, from2=Q109927865 Rangeomorpha Fossil taxa described in 2009