''Calocedrus huashanensis'' is an extinct

incense-cedar ''Calocedrus'', the incense cedar (alternatively spelled incense-cedar), is a genus of coniferous trees in the cypress family Cupressaceae first described as a genus in 1873. Three species are native to East Asia, eastern Asia and one to wester ...

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

in the family

Cupressaceae Cupressaceae or the cypress family is a family of conifers. The family includes 27–30 genera (17 monotypic), which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdioecious or (rarely) dioecio ...

described from a group of isolated foliage

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

s including stems and leaves. The species is known from

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

sediments exposed in the

Guangxi Zhuang Autonomous Region Guangxi,; officially the Guangxi Zhuang Autonomous Region, is an autonomous region of the People's Republic of China, located in South China and bordering Vietnam ( Hà Giang, Cao Bằng, Lạng Sơn, and Quảng Ninh Provinces) and the ...

, China. It is one of a number of extinct species placed in the living genus ''Calocedrus''.

History and classification

''Calocedrus huashanensis'' is represented by a series of

compression fossil A compression fossil is a fossil preserved in sedimentary rock that has undergone physical compression. While it is uncommon to find animals preserved as good compression fossils, it is very common to find plants preserved this way. The reason f ...

specimens in lacustrine deposits belonging to the

aged Ningming Formation of western Ningming County. As of 2011 the formation had not been dated by

radiometric Radiometry is a set of techniques for measuring electromagnetic radiation, including visible light. Radiometric techniques in optics characterize the distribution of the radiation's power in space, as opposed to photometric techniques, which ch ...

methods, making a precise date difficult to obtain. The Ningming Formation overlies the Dazha Formation, which has been dated to the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

and palynological studies of the pollens preserved in the Ningming Formation have given a general age of Oligocene. The pollen studies are supported by both the fish and plant megafossils that are found in the formation, both of which support an Oligocene age. The flora preserved in the formation appears to have been a subtropical evergreen forest almost exclusively dominated by

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s. ''C. huashanensis'' is one of only three species of

conifer Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

s found in the formation. The species is one of two members of the family Cupressaceae while the third conifer species, the plum-yew '' Cephalotaxus ningmingensis'' was described in 2010. The type specimens for ''C. huashanensis'' are located in two different repositories. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

specimen, number "NHMG-010420", is currently preserved in paleobotanical collections housed at the Natural History Museum of Guangxi Zhuang Autonomous Region. The two paratype specimens, "PB21097" and "PB21098", are housed at the Nanjing Institute of Geology and Palaeontology, a branch of the

Chinese Academy of Sciences The Chinese Academy of Sciences (CAS; ) is the national academy for natural sciences and the highest consultancy for science and technology of the People's Republic of China. It is the world's largest research organization, with 106 research i ...

Nanjing Nanjing or Nanking is the capital of Jiangsu, a province in East China. The city, which is located in the southwestern corner of the province, has 11 districts, an administrative area of , and a population of 9,423,400. Situated in the Yang ...

. The specimens were studied by a group of three Chinese

paleobotanist Paleobotany or palaeobotany, also known as paleophytology, is the branch of botany dealing with the recovery and identification of plant fossils from geological contexts, and their use for the biological reconstruction of past environments (pale ...

s, led by Gongle Shi, all from the Nanjing Institute of Geology and Palaeontology. Gongle Shi and team published their 2012 type description for ''C. huashanensis'' in the ''

American Journal of Botany The ''American Journal of Botany'' is a monthly peer-reviewed scientific journal which covers all aspects of plant biology. It has been published by the Botanical Society of America since 1914. The journal has an impact factor of 3.038, as of 20 ...

''. The

etymology Etymology ( ) is the study of the origin and evolution of words—including their constituent units of sound and meaning—across time. In the 21st century a subfield within linguistics, etymology has become a more rigorously scientific study. ...

of the chosen specific name ''huashanensis'' is in recognition of the Huashan Hills, near the type locality, which are noted for an ancient fresco on a cliff.

Description

While the foliage of ''C. huashanensis'' is similar in overall appearance to several Cupressaceae genera, the details of the cuticle structure and overall morphology indicate the species is part of the genus ''Calocedrus''. ''C. huashanensis'' differs from the living '' C. formosana'' by having less obtuse-shaped facial leaves and side leaves that do not incurve. The living North American species '' C. decurrens'' differs from ''C. huashanensis'' in the slightly flattened morphology of the leafy shoots and the weakly dimorphic leaves. ''C. huashanensis'' and the modern '' C. macrolepis'' can be separated by the distribution of the stomal zones of the leaves on the undersides of shoots.

References

{{Taxonbar, from=Q5023074 huashanensis Plants described in 2012 Fossil taxa described in 2012 Oligocene plants Flora of China Prehistoric trees