In:
Plant Systematics and Evolution, Springer Science and Business Media LLC, Vol. 310, No. 4 ( 2024-08)
Abstract:
Elongated biconvex Carex fossil fruits are relatively common in fossil assemblages, but they are of much uncertain taxonomic affinity. Three fossil-species have been erected to accommodate the materials from the respective type localities ( C. klarae , C. paucifloriformis and C. paucifloroides ) and a number of superficially similar-looking fossils were reported from other sites. The formerly proposed affinities mostly pointed to the extant C. pauciflora (subgen. Euthyceras ) or Carex sect. Cyperoideae (subgen. Vignea ), depending on the authors. But despite the similar superficial resemblance of the fossil remains to these not very closely related sedge taxa, other groups are also possible matches. We used a comparative approach employing stereomicroscope and SEM to analyze the affinities of several Old World “mummified” fossils (ca. 23 to 0.1 Ma) of elongated biconvex fruits. Several samples showed a fair preservation of previously unattested microscopic characters. In particular, one of them allowed us to detect an indirect record of fine silica body morphologies (impressions) on the periclinal walls, which permitted the sound taxonomic placement of the remains from the Miocene of Siberia as a Carex sect. Cyperoideae . In all the other fossils analyzed, the epidermal cell outline and the central position of the main silica body were sufficient to discard assignment to subgen. Euthyceras , despite a purported affinity to C. pauciflora reported in previous literature. In the absence of detailed information on silica bodies, epidermal cell (exocarp) details in fossil specimens do not seem to be determinant for the systematic placement. However, the addition of diagnostic style characters pointed to sect. Cyperoideae as the best match with the available information. Our data support a continued presence of Carex sect. Cyperoideae in the Old World since the Miocene, which candidates Eurasia as a possible place of origin for it, despite DNA-based reconstructions alone proposed North America. This study underlines the importance of detailed taxonomic studies to properly address the identity of fossils and unravel the biogeographic history of plants.
Type of Medium:
Online Resource
ISSN:
0378-2697
,
1615-6110
DOI:
10.1007/s00606-024-01903-4
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
2024
detail.hit.zdb_id:
7485-8
detail.hit.zdb_id:
1463027-8
detail.hit.zdb_id:
2781142-6
SSG:
12
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