Melvillipteris quadriseriata gen. et sp nov., a new plant assigned to Rhacophytales from the Upper Devonian (Famennian) of Arctic Canada
A new plant of Late Devonian (Famennian) age, Melvillipteris quadriseriata gen. et sp. nov., is reported from Melville Island, Nunavut, Canadian Arctic Archipelago. Main axes and two orders of lateral branches are recognized. The main axes are monopodial in habit, with a zigzag and/or upright appear...
Published in: | Geological Magazine |
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Main Authors: | , |
Other Authors: | , , , |
Format: | Journal/Newspaper |
Language: | English |
Published: |
GEOLOGICAL MAGAZINE
2016
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Subjects: | |
Online Access: | https://hdl.handle.net/20.500.11897/492077 https://doi.org/10.1017/S0016756815000746 |
Summary: | A new plant of Late Devonian (Famennian) age, Melvillipteris quadriseriata gen. et sp. nov., is reported from Melville Island, Nunavut, Canadian Arctic Archipelago. Main axes and two orders of lateral branches are recognized. The main axes are monopodial in habit, with a zigzag and/or upright appearance and dense adventitious roots attached on some internodes. First-order branches are inserted on the main axes in distichous pairs, showing a quadriseriate pattern (i.e. alternate pairs); they bear one or two sterile ultimate appendages on the proximal portions, and then distally bear alternate second-order branches. Second-order branches bear alternate ultimate appendages which may be fertile or sterile; the sterile ultimate appendages are composed of one or two successive dichotomies, terminating in oppositely recurved tips, and fertile appendages show an elaborate branching system. Each fertile appendage has an initial dichotomy forming two sister branches, each of which further divides three or four times to produce ultimate divisions terminated by sporangia. Two to four small fusiform sporangia are grouped in a truss which is supplied by penultimate division of the fertile appendage. The sporangia have a pointed tip and a longitudinal dehiscence. This new plant resembles other plants with a quadriseriate branching pattern (e.g. Rhacophyton Crepin, Cephalopteris Nathorst, Protocephalopteris Ananiev, Ellesmeris Hill, Scheckler & Basinger and Protopteridophyton Li & Hsu), and is assigned to the Rhacophytales. Its similarity to and divergence from the rhacophytaleans, cladoxylopsids and other related plants are discussed. Natural Sciences and Engineering Research Council of Canada [DG 1334]; University of Saskatchewan; National Natural Science Foundation of China [41272018] SCI(E) ARTICLE pkuxue@pku.edu.cn; jim.basinger@usask.ca 4 601-617 153 |
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