Zakrevskaya M.A., Ivantsov A.Yu. 2017. Dickinsonia costata — the first evidence of neoteny in Ediacaran organisms // Invertebrate Zoology. Vol.14. No.1: 92–98 [in English].

A.A. Borissiak Paleontological Institute of RAS, Profsoyuznaya st., 123, Moscow, 117647, Russia. E-mail: mariazakrevskaya@gmail.com ivancov@paleo.ru

ABSTRACT: Some of the most famous organisms of the Late Precambrian are representatives of the genus Dickinsonia. Four species of Dickinsonia are found throughout the section, characterized by macrofossils, on the southeastern White Sea area. However, their distribution is uneven. Two species, D. costata and D. tenuis are the most common, while the other two occur sporadically. At the lower levels (Verkhovka Formation) thin-segmented D. tenuis is the most frequently encountered. There are few imprints that can be attributed to D. costata, and all of them are of small size. Numerous specimens of D. costata, representing all available for study stages of ontogeny, are present only at the upper stratigraphic levels — in the Zimnie Gory and Erga formations. The statistical analysis of Dickinsonia imprints from a number of fossil assemblages in the southeastern White Sea shows an existence of two distinct groups that could represent different stages of ontogeny of a single species — D. tenuis. All the features of the juvenile D. tenuis — a round body,  enlarged head part and a small number of trunk isomers — are distinctive features of D. costata. These features are preserved in mature D. costata. The most likely explanation of this phenomenon is the origin of D. costata from D. tenuis by neoteny.

doi: 10.15298/invertzool.14.1.13

KEY WORDS: Ediacaran biota, Vendian, Metazoa, Invertebrate paleontology, Dickinsonia.

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