Fossil nutlets of Boraginaceae from the continental Eocene of Hamada of Méridja (southwestern Algeria): The first fossil of the Borage family in Africa
PREMISE OF THE STUDY: The Paleogene deposits of the Hamada of Méridja, southwestern Algeria, are currently dated as lower-to-middle Eocene in age based on fossil gastropods and charophytes. Here we report the presence of fruits that can be assigned to the Boraginaceae s. str., apparently representin...
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Published in | American journal of botany Vol. 102; no. 12; pp. 2108 - 2115 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Botanical Society of America, Inc
01.12.2015
Botanical Society of America |
Subjects | |
Online Access | Get full text |
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Summary: | PREMISE OF THE STUDY: The Paleogene deposits of the Hamada of Méridja, southwestern Algeria, are currently dated as lower-to-middle Eocene in age based on fossil gastropods and charophytes. Here we report the presence of fruits that can be assigned to the Boraginaceae s. str., apparently representing the first fossil record for this family in Africa, shedding new light on the historical biogeography of this group. METHODS: Microscopic studies of the fossil nutlets were carried out and compared to extant Boraginaceae nutlets, and to types reported in the literature for this family. KEY RESULTS: The fossils are strikingly similar in general size and morphology, particularly in the finer details of the attachment scar and ornamentation, to nutlets of extant representatives of the Boraginaceae tribe Echiochileae, and especially the genus Ogastemma. We believe that these nutlets represent an extinct member of this lineage. CONCLUSIONS: The Ogostemmo-Wke fossils indicate that the Echiochileae, which are most diverse in northern Africa and southwestern Asia, have a long history in this region, dating back to the Eocene. This tribe corresponds to the basal-most clade in Boraginaceae s. str., and the fossils described here agree well with an assumed African origin of the family and the Boraginales I, providing an important additional calibration point for dating the phylogenies of this clade. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0002-9122 1537-2197 |
DOI: | 10.3732/ajb.1500350 |