''Hapsidophyllas'' is a rare

Ediacaran The Ediacaran Period ( ) is a geological period that spans 96 million years from the end of the Cryogenian Period 635 million years ago (Mya), to the beginning of the Cambrian Period 538.8 Mya. It marks the end of the Proterozoic Eon, and th ...

rangeomorph The rangeomorphs are a form taxon of frondose Ediacaran Ediacaran biota, fossils that are united by a similarity to ''Rangea''. Some researchers, such as Pflug and Narbonne, suggest that a natural taxon Rangeomorpha may include all similar-look ...

fossil found at

Mistaken Point Mistaken Point Ecological Reserve is a wilderness area and a UNESCO World Heritage Site located at the southeastern tip of Newfoundland's Avalon Peninsula in the Canadian province of Newfoundland and Labrador. The reserve is home to the namesak ...

Newfoundland Newfoundland and Labrador (; french: Terre-Neuve-et-Labrador; frequently abbreviated as NL) is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

. It was first identified by Emily Bamforth and Guy Narbonne in 2009. Its name comes from the Greek words for “a network of leaves.” 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. 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 ''Charnia'' is a genus of frond-like lifeforms belonging to the Ediacaran biota with segmented, leaf-like ridges branching alternately to the right and left from a zig-zag medial suture (thus exhibiting glide reflection, or opposite isometry). T ...

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

photic zone The photic zone, 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 proc ...

. 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