Retrophyllum
Encyclopedia
Retrophyllum is a genus
of coniferous gymnosperm
s in the family
Podocarpaceae
. It has a disjunct distribution
in the Southern Hemisphere
. Four or five species
are recognized.
Fossil Record
Retrophyllum shoots have a distinctive morphology in which the leaves are in opposite pairs, and twisted in such a way that the abaxial surface of one leaf is up, and in the other it is down. This feature, added to a distinctive epidermal morphology means that well-preserved specimens can be easily identified in the fossil record. The fossil record shows that Retophyllum was present in the Cenozoic of Australia (Hill and Pole 1992) and New Zealand (Pole 1992, 1997). It is now extinct in both places.
Taxonomy
In a 2009 book on conifers, Retrophyllum piresii was treated as conspecific
with Retrophyllum rospigliosii. The author stated "One specimen from low elevations in Brazil was separated as a distinct species, but it falls well within the range of variation of the species as a whole and is geographically close to some locations in Peru."
Pole, M.S., 1992. Early Miocene flora of the Manuherikia Group, New Zealand. 2. Conifer. Journal of the Royal Society of New Zealand, 22: 287-302.
Pole, M.S., 1997. Miocene conifers from the Manuherikia Group, New Zealand. Journal of the Royal Society of New Zealand, 27: 355-370.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of coniferous gymnosperm
Gymnosperm
The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of their seeds...
s in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Podocarpaceae
Podocarpaceae
Podocarpaceae is a large family of mainly Southern Hemisphere conifers, comprising about 156 species of evergreen trees and shrubs. It contains 19 genera if Phyllocladus is included and if Manoao and Sundacarpus are recognized....
. It has a disjunct distribution
Disjunct distribution
In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but widely separated from each other geographically...
in the Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
. Four or five species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
are recognized.
Fossil Record
Retrophyllum shoots have a distinctive morphology in which the leaves are in opposite pairs, and twisted in such a way that the abaxial surface of one leaf is up, and in the other it is down. This feature, added to a distinctive epidermal morphology means that well-preserved specimens can be easily identified in the fossil record. The fossil record shows that Retophyllum was present in the Cenozoic of Australia (Hill and Pole 1992) and New Zealand (Pole 1992, 1997). It is now extinct in both places.
Taxonomy
In a 2009 book on conifers, Retrophyllum piresii was treated as conspecific
Conspecificity
Conspecificity is a concept in biology. Two or more individual organisms, populations, or taxa are conspecific if they belong to the same species....
with Retrophyllum rospigliosii. The author stated "One specimen from low elevations in Brazil was separated as a distinct species, but it falls well within the range of variation of the species as a whole and is geographically close to some locations in Peru."
Sources
Hill, R.S. and Pole, M.S., 1992. Leaf and Shoot Morphology of Extant Afrocarpus, Nageia and Retrophyllum (Podocarpaceae) Species, and Species with similar Leaf Arrangement from Tertiary sediments in Australasia. Australian Systematic Botany.Pole, M.S., 1992. Early Miocene flora of the Manuherikia Group, New Zealand. 2. Conifer. Journal of the Royal Society of New Zealand, 22: 287-302.
Pole, M.S., 1997. Miocene conifers from the Manuherikia Group, New Zealand. Journal of the Royal Society of New Zealand, 27: 355-370.