Morphology and palaeoenvironmental context ofFouldenia staminosa, a fossil flower with associated pollen from the Early Miocene of Otago, New Zealand

Abstract

A new genus and species, Fouldenia staminosa, are proposed for an angiosperm flower with associated pollen bearing anthers found in Early Miocene finely laminated lacustrine diatomite at Foulden Hills, Otago. This is the first New Zealand record of a Miocene flower with in situ pollen and among few such records worldwide. The pollen is closely similar to Rubipollis oblatus, of unknown affinity, known from Late Oligocene to Early Miocene strata elsewhere in New Zealand and Australia, but differs in being spheroidal to subprolate. In spite of the relatively good preservation of both the flower and its pollen it has not been possible to assign this species to an extant genus or even family. The highly diverse angiosperm pollen flora from the same bedding plane in the diatomite indicates that Fouldenia grew in a dry, warm temperate to subtropical climate.

High-frequency paleoclimate signals from Foulden Maar, Waipiata Volcanic Field, southern New Zealand: An Early Miocene varved lacustrine diatomite deposit

“…Laminated sediments similar to those described here have been shown to provide exceptional high resolution records of proxy climate information (e.g., Vos et al, 1997;Lücke et al, 2003). On the basis of studies of nonmarine macrofauna, macroflora, pollen and spores (Pocknall and Mildenhall, 1984;Mildenhall and Pocknall, 1989;Pocknall, 1989;Molnar and Pole, 1997;Pole, 2003;Pole et al, 2003;Bannister et al, 2005), sedimentation patterns (Douglas, 1986;Isaac and Lindqvist, 1990), and coastal fauna, Miocene south-eastern New Zealand is considered to have been of low topographic relief and to have had a warm temperate to subtropical, humid but at times seasonally dry, maritime climate. The presence of Early Miocene colonial corals in North Island (Campbell et al, 2004) also indicates that sub-tropical sea temperatures existed in the New Zealand region during this time.…”

The Miocene climate in New Zealand: Estimates from paleobotanical data

“…However, correlation with the 16 Ma event would imply that the Spinitricolpites latispinosus Zone is almost entirely early Miocene and, therefore, there is a problem with the Mildenhall et al (2003) application of it to the middle Miocene Bryce Burn. Correlation with the 12.6 Ma event, as well as Mildenhall et al's suggestion of a correlation with a "New Zealand-wide change in the vegetation which occurs in the late Miocene (Mildenhall 1980) at 8 Ma," are simply incompatible with the Youngson et al (1998) 13.4 Ma K-Ar date from well above the vegetation shift (see Pole, 2003, p.280-281) A further development in the dating of the Miocene palynological zones was provided by Bannister et al (2005). They provided results from a palynological sample of the Foulden Maar that is associated with volcanics radiometrically dated to 23-24 Ma, thus the Waitakian stage and close to the Oligocene-Miocene boundary.…”

“…There are various reports in the paleobotanical literature to the effect that the genera indicate dry conditions. For example, some of the evidence leading to a conclusion that the Foulden Hills Diatomite vegetation experienced "at least seasonally dry periods," was the claim by Bannister et al (2005) that Mallotus and/or Macaranga "inhabited dry forest margins" in Australia. This is misleading as the genera have very wide ranges.…”

“…One of the few full palynological lists and counts for a Miocene location, Foulden Maar, was presented by Bannister et al (2005). Based on the "highly diverse angiosperm pollen flora" they regarded the climate as "dry, warm temperate to subtropical."…”

“…Nothofagus was absent and conifers were represented by one species of large-leaved Podocarpus (Pole, 1993b). Subsequently published material includes flowers (Bannister et al, 2005;Lee et al, 2010), orchids (Conran et al, 2009), ferns (Conran et al, 2010, Lauraceae (Bannister et al, 2012), and Laurelia (Conran et al, 2013). Cornish Head.…”