Abstract Detail



Paleobotany

Geary, Ian [1], Beever, Jessica [2], Lee, Daphne [1], Conran, John [3], Lord, Janice [4].

A diverse assemblage of exquisite Pliocene mosses from northern New Zealand.

An exceptional assemblage of fossil mosses (Bryophyta) has recently been recovered from several Late Pliocene (Waipipian, 3.7–3.0 Ma) localities near Auckland, New Zealand. These localities yield important plant and fungal macrofossils in the estuarine, fluvial and near shore sediments of the Tauranga Group. Close inspection of the finer-grained, leaf-bearing sediments has revealed an almost overlooked diversity of exquisitely-preserved fossil mosses. Moss macrofossils are uncommon globally and New Zealand has just two prior records, both of Mesozoic age. These newly discovered fossil mosses represent the first Cenozoic specimens reported from New Zealand and they also comprise the first fossil moss flora from the region.
The fossil mosses are organically-preserved microphylls and stem fragments. Although soft, they are resilient and tolerant of mechanical extraction and cleaning, making them well-suited to traditional identification methods using transmitted light microscopy. To date, no sporophytes have been recovered, although the gametophytes are highly diagnostic, with more than 15 fossil moss morphotypes currently recognised, including Homalia, Ptychomnion (c.f. P. aciculare), Pyrrhobryum, Wijkia (c.f. W. extenuata), Papillaria and Hypnodendraceae. Several morphotypes resemble extant New Zealand species such as Calyptrochaeta cristata and Fissidens rigidulus. Mosses are apparently long-lived at the species level, with even Miocene (23–5 Ma) specimens often being identified as modern species. It is therefore not surprising that most of these fossils share possible affinities with, or are otherwise indistinguishable from, gametophytes of extant species and only one specimen appears to represent a possibly locally-extinct taxon.
The fossil mosses co-occur with a warm-indicative vascular flora that includes groups that have experienced high floristic turnover since the Late Pliocene. The mosses complement the vascular plant fossils by providing a unique insight into the relatively recent, but very different terrestrial forest ecosystems of pre-Pleistocene northern New Zealand and the species living there.


1 - University of Otago, Department of Geology, PO Box 56, Dunedin, New Zealand
2 - Manaaki Whenua Landcare Research, 231 Morrin Rd, St Johns, Auckland, New Zealand
3 - The University Of Adelaide, School Of Biological Sciences, Benham Bldg, DX650 312, Adelaide, SA 5005, Australia
4 - University of Otago, Department of Botany, PO Box 56, Dunedin, New Zealand

Keywords:
paleobotany
Fossil bryophytes.

Presentation Type: Poster
Number: PPB003
Abstract ID:732
Candidate for Awards:None


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