''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. It is native to eastern Asia and western North America. The generic ...

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

in the family

Cupressaceae Cupressaceae is a conifer family, the cypress family, with worldwide distribution. The family includes 27–30 genera (17 monotypic), which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdio ...

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 preserved ...

s including stems and leaves. The species is known from

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but ...

sediments exposed in the

Guangxi Zhuang Autonomous Region Guangxi (; ; alternately romanized as Kwanghsi; ; za, Gvangjsih, italics=yes), officially the Guangxi Zhuang Autonomous Region (GZAR), is an autonomous region of the People's Republic of China, located in South China and bordering Vietnam ...

, 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 A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...

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

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 (), commonly called angiosperms. They include all forbs (flowering plants without a woody stem), grasses and grass-like plants, a vast majority of ...

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

conifer Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All ex ...

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 ''Cephalotaxus'', commonly called plum yew or cowtail pine, is a genus of conifers comprising 11 species, treated in either the Cephalotaxaceae, or in the Taxaceae when that family is considered in a broad sense. The genus is endemic to eastern A ...

'' was described in 2010. The type specimens for ''C. huashanensis'' are located in two different repositories. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

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); ), known by Academia Sinica in English until the 1980s, is the national academy of the People's Republic of China for natural sciences. It has historical origins in the Academia Sinica during the Repub ...

Nanjing Nanjing (; , Mandarin pronunciation: ), Postal Map Romanization, alternately romanized as Nanking, is the capital of Jiangsu Provinces of China, province of the China, People's Republic of China. It is a sub-provincial city, a megacity, and t ...

. The specimens were studied by a group of three Chinese

paleobotanist Paleobotany, which is also spelled as palaeobotany, is the branch of botany dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments (paleogeogr ...

s, led by Gongle Shi, all from the Nanjing Institute of Geology and Palaeontology. Gongle Shi and team published their 2012

type description A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have ...

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 201 ...

''. The

etymology Etymology () The New Oxford Dictionary of English (1998) – p. 633 "Etymology /ˌɛtɪˈmɒlədʒi/ the study of the class in words and the way their meanings have changed throughout time". is the study of the history of the form of words ...

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