Welwitschiaceae is a family of plants of the order

Gnetales Gnetophyta () is a division of plants (alternatively considered the subclass Gnetidae or order Gnetales), grouped within the gymnosperms (which also includes conifers, cycads, and ginkgos), that consists of some 70 species across the three reli ...

with one living species, ''

Welwitschia mirabilis ''Welwitschia'' is a monotypic gymnosperm genus, comprising solely the distinctive ''Welwitschia mirabilis'', endemic to the Namib desert within Namibia and Angola. ''Welwitschia'' is the only living genus of the family Welwitschiaceae and ord ...

'', found in southwestern Africa. Three fossil genera have been recovered from the

Crato Formation The Crato Formation is a geologic formation of Early Cretaceous (Aptian) age in northeastern Brazil's Araripe Basin. It is an important Lagerstätte (undisturbed fossil accumulation) for palaeontologists. The strata were laid down mostly during ...

– late Aptian (

Lower Cretaceous Lower may refer to: *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eig ...

) strata located in the

Araripe Basin The Araripe Basin () is a rift basin covering about ,Neto et al., 2013, p.1 in Ceará, Piauí and Pernambuco states of northeastern Brazil. It is bounded by the Patos and Pernambuco lineaments, and is situated east of the Parnaíba Basin, southwe ...

in northeastern Brazil, with one of these also being known from the early Late Cretaceous ( Cenomanian-

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded b ...

) Akrabou Formation of Morocco.

Taxonomy

German naturalist

Friedrich Markgraf Friedrich Markgraf (1 February 1897 in Berlin-Friedenau – 8 March 1987 in Zurich) was a German botanist. Life and work After secondary school, Markgraf studied biology at the Friedrich Wilhelm University Berlin. In 1922 he was awarded a ...

coined the name Welwitschiaceae in 1926, which appeared in ''

Die Natürlichen Pflanzenfamilien ''Die Natürlichen Pflanzenfamilien'' (1887–1915) by Adolf Engler (1844–1930) and Karl Anton Prantl is a complete revision of plant families down to generic level and often even further. As such it forms part of the Engler system of plant t ...

''. Most recent systems place the Welwitschiaceae in the

gymnosperm The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers, cycads, '' Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, γυμν ...

order

. This order is most closely related to the order

Pinales The order Pinales in the division Pinophyta, class Pinopsida, comprises all the extant conifers. The distinguishing characteristic is the reproductive structure known as a cone produced by all Pinales. All of the extant conifers, such as cedar, ...

, which includes

Araucariaceae Araucariaceae – also known as araucarians – is an extremely ancient family of coniferous trees. The family achieved its maximum diversity during the Jurassic and Cretaceous periods and the early Cenozoic, when it was distributed almost worldw ...

- Araucarians, Cupressaceae - Cypress Family,

Pinaceae The Pinaceae, or pine family, are conifer trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, firs, hemlocks, larches, pines and spruces. The family is included in the order Pinales, formerly kn ...

- Pine Family,

Podocarpaceae Podocarpaceae is a large family of mainly Southern Hemisphere conifers, known in English as podocarps, comprising about 156 species of evergreen trees and shrubs.James E. Eckenwalder. 2009. ''Conifers of the World''. Portland, Oregon: Timber Pr ...

- Podocarps, Sciadopityaceae - Koyamaki Family (the sole membe
Sciadopitys verticillata - Koyamaki
,

Taxaceae Taxaceae (), commonly called the yew family, is a coniferous family which includes six extant and two extinct genera, and about 30 species of plants, or in older interpretations three genera and 7 to 12 species. Description They are many-bran ...

- Yew Family. Genetic analyses indicate that the Gnetales arose from within the conifer group, and any morphological similarities between angiosperms and Gnetales have evolved separately. The ancestors of the extant gymnosperm orders—Gnetales, Coniferales, Cycadales and Ginkgoales—arose during the Late Paleozoic, and became the dominant component of the

Late Permian Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effect, ...

and Mesozoic flora.

Living species

The family contains a single genus and single extant species, ''

'', which lives in the

Kaokoveld The Kaokoveld Desert is a coastal desert of northern Namibia and southern Angola. Setting The Kaokoveld Desert occupies a coastal strip covering , from 13° to 21°S and is bounded by the Atlantic Ocean to the west, the Namibian savanna woodl ...

Desert of Angola and Namibia in southwestern Africa.

Fossil species

Fossil evidence indicates that members of the Welwitschiaceae were present in South America during the Early Cretaceous (Mesozoic era). '' Priscowelwitschia austroamericana'' (initially named ''Welwitschiella'' but illegitimate due to the daisy genus '' Welwitschiella'') is a fossil taxon referring to some seedlings with

cotyledon A cotyledon (; ; ; , gen. (), ) is a significant part of the embryo within the seed of a plant, and is defined as "the embryonic leaf in seed-bearing plants, one or more of which are the first to appear from a germinating seed." The num ...

leaves. These have many features in common with ''Welwitschia'' seedlings. '' Welwitschiophyllum brasiliense'' is a taxon known from thick triangular to linear leaves that range from 8.9 to 70 cm long and 2.8–5 cm wide. '' Welwitschiostrobus murili'' is a fossil taxon known from some cones that resemble the living ''Welwitschia'', but are longer and thinner. Jacobson and Lester suggest that these early habitats were more mesic than the current desert conditions, and that the present fragmented and isolated population distribution could be attributed to

aridification Aridification is the process of a region becoming increasingly arid, or dry. It refers to long term change, rather than seasonal variation. It is often measured as the reduction of average soil moisture content. It can be caused by reduced precip ...

during the Paleogene, Neogene, and Quaternary, which restricted the plants to locales providing sufficient water for their needs.

References

{{Taxonbar, from=Q10780833 Plant families Extant Aptian first appearances