Avalofractus

Avalofractus abaculus
Temporal range: Ediacaran
Scientific classification
Clade: †Rangeomorpha
Genus: †Avalofractus
Species: †A. abaculus
Binomial name
Avalofractus abaculus
Narbonne et al., 2009

Avalofractus abaculus is a frond-like rangeomorph fossil described from the Ediacaran of the Trepassey Formation, Spaniard's Bay, Newfoundland.[1]

Morphology

Avalofractus displays a strongly fractal body shape, with four levels of nearly perfectly self-similar, pinnate, alternate branches. It was about 5 cm long on average, with a 1 cm-diameter holdfast at the base of the frond. The stem length is from 1/3 to 1/2 that of the whole frond. It is quite similar to Rangea, even if with distinct morphological differences that justify the creation of a new genus (e.g. absence of subsidiary quilts, frond elements free to rotate independently instead of being attached to each other by a membrane).[1]

Distribution

In contrast with other rangeomorphs, which have wide distributions, Avalofractus seems to have been an endemic species, being known only from the Spaniard's Bay deposits.[1]

Reproduction

It has been suggested that Avalofractus could have been capable of vegetative reproduction: loose fronds could have detached and grow, rather like a plant cutting. This could explain the mysterious lack of independent rangeomorph fronds smaller than 10 mm in the fossil record.[1]

A previous suggestion that Avalofractus younger individuals were encased in a sheath-like structure has been later dismissed.[2]

See also

List of Ediacaran genera

References

  1. 1 2 3 4 Narbonne, G. M.; Laflamme, M.; Greentree, C.; Trusler, P. (2009). "Reconstructing a Lost World: Ediacaran Rangeomorphs from Spaniard's Bay, Newfoundland". Journal of Paleontology. 83 (4): 503. doi:10.1666/08-072R1.1.
  2. ↑ Brasier, M. D.; Liu, A. G.; Menon, L.; Matthews, J. J.; McIlroy, D.; Wacey, D. (2013). "Explaining the exceptional preservation of Ediacaran rangeomorphs from Spaniard's Bay, Newfoundland: A hydraulic model". Precambrian Research. 231: 122. doi:10.1016/j.precamres.2013.03.013.


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