Falcatifolium (Podocarpaceae) macrofossils from paleogene sediments in south-eastern Australia: a reassessment

1998 ◽  
Vol 11 (6) ◽  
pp. 711 ◽  
Author(s):  
Robert S. Hill ◽  
Leonie J. Scriven
Keyword(s):  
Leaf Morphology ◽  
Middle Eocene ◽  
Late Eocene ◽  
South Eastern ◽  
Early Oligocene ◽  
Extant Species ◽  
Eastern Australia ◽  
South Eastern Australia

A re-investigation of macrofossils previously referred to the extantpodocarpaceous genus Falcatifolium Laubenfels shows thatno records can be sustained. Falcatifolium australisD.R.Greenwood from Middle Eocene sediments in Victoria bears littleresemblance to extant species in the genus and is transferred to the newfossil genus Sigmaphyllum R.S.Hill & L.J.Scriven.Specimens from Early Oligocene sediments in Tasmania previously assigned toFalcatifolium are described as a second species ofSigmaphyllum, S. tasmanensisR.S.Hill & L.J.Scriven, and specimens from mid to late Eocene sediments inTasmania previously assigned to Falcatifolium do notbelong to that genus, although their true generic affinities are uncertain.Dispersed cuticle specimens from Late Eocene–Oligocene sediments inSouth Australia referred to Falcatifolium are notreliable records of the genus and require further investigation. However,Dacrycarpus eocenica D.R.Greenwood, from Middle Eocenesediments in Victoria is transferred to Falcatifolium,and is similar to the extant species F. angustumLaubenfels, which has a leaf morphology unusual for the genus.Falcatifolium eocenica (D.R.Greenwood) R.S.Hill & L.J.Scriven is the only reliable record of the genus in the Australian fossilrecord to date.

Leaves of Eucryphia (Eucryphiaceae) from tertiary sediments in south-eastern Australia

1991 ◽  
Vol 4 (3) ◽  
pp. 481 ◽  
Author(s):  
RS Hill
Keyword(s):  
Leaf Surface ◽  
Late Eocene ◽  
Early Pleistocene ◽  
South Eastern ◽  
Early Tertiary ◽  
Abaxial Leaf Surface ◽  
Extant Species ◽  
Eastern Australia ◽  
Three New Species ◽  
South Eastern Australia

Eucryphia leaves recovered from Tertiary sediments in south-eastern Australia are assigned to three new species, E. falcata (Late Palaeocene, Lake Bungarby), E. microstoma (Early Eocene, Regatta Point) and E. aberensis (Middle to Late Eocene, Loch Aber). Leaves from Early Pleistocene sediments at Regatta Point are re-examined and are considered to be closely related to the extant species, E. lucida and E. milliganii. An examination of the leaf morphology of the fossil and extant species suggests that evolution has taken place, resulting in smaller leaves at higher latitudes and/or altitudes probably in response to climatic change. There is also evidence for an increase in the size and complexity of peltiform cuticular extensions on the abaxial leaf surface from the Early Tertiary to the present, which may be a response to lower water availability or increasing occurrence of frost.

Two new species of Dacrydium (Podocarpaceae) based on vegetative fossils from middle eocene sediments at Nelly Creek, South Australia

2001 ◽  
Vol 14 (2) ◽  
pp. 193 ◽  
Author(s):  
Robert S. Hill ◽  
David C. Christophel
Keyword(s):  
New Species ◽  
Water Availability ◽  
Middle Eocene ◽  
South Australia ◽  
South Eastern ◽  
Early Oligocene ◽  
Eastern Australia ◽  
Two New Species ◽  
Central Australia ◽  
South Eastern Australia

Two new macrofossil species of Dacrydium (Podocarpaceae), D. fimbriatus (with dimorphic foliage) and D. mucronatus, are described from Middle Eocene sediments at Nelly Creek just south of Lake Eyre South. These species extend the number of Dacrydium macrofossil species from four to six, the macrofossil range from south-eastern to central Australia and the earliest macrofossil record of the genus from the Early Oligocene to Middle Eocene. On the basis of the low numbers and poor development of epiphyllous germlings, these species were probably growing in a region where water availability was reduced compared with Paleogene sites in south-eastern Australia, but the morphology of the foliage does not reflect that.

Evolution of Acmopyle and Dacrycarpus (Podocarpaceae) foliage as inferred from macrofossils in south-eastern Australia

1991 ◽  
Vol 4 (3) ◽  
pp. 449 ◽  
Author(s):  
RS Hill ◽  
RJ Carpenter
Keyword(s):  
New Species ◽  
Climatic Change ◽  
Convergent Evolution ◽  
Leaf Size ◽  
High Latitudes ◽  
South Eastern ◽  
Early Oligocene ◽  
Eastern Australia ◽  
A New Species ◽  
South Eastern Australia

Macrofossil specimens of Dacrycarpus and Acmopyle from south-eastern Australia are investigated. The specimens previously assigned to D. praecupressinus are revised, with one placed in a different genus and new species, Podocarpus witherdenensis, and some placed in a new species, D. latrobensis. One specimen is retained as the lectotype of D. praecupressinus. Dacrycarpus eocenica is re-examined and it is concluded that this species is not Dacrycarpus, but probably belongs to an extinct podocarpaceous genus. Dacrycarpus setiger is transferred to Acmopyle, and three new Acmopyle species, A. florinii, A. glabra and A. tasmanica, are described. It is hypothesised that during the Tertiary in south-eastern Australia stomatal distribution was reduced on Dacrycarpus and Acmopyle foliage. In Dacrycarpus the bilaterally flattened foliage type (which has a greater photosynthetic area than the bifacially flattened foliage) became rare or extinct after the Early Oligocene, prior to the extinction of the genus in the region. Acmopyle has not been recorded in the region after the Early Oligocene. A trend towards reduction in leaf size at high latitudes has previously been demonstrated in angiosperms but not gymnosperms and, along with the reduction of stomatal distribution, probably represents convergent evolution in response to climatic change.

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