''Banksia novae-zelandiae'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

species of ''

Banksia ''Banksia'' is a genus of around 170 species in the plant family Proteaceae. These Australian wildflowers and popular garden plants are easily recognised by their characteristic flower spikes, and fruiting "cones" and heads. ''Banksias'' range i ...

'', known only from

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 ...

leaves found in the

South Island The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

Description

This species is based on several leaf fossils, all with triangular pinnate lobes cut all the way back to the midrib, and indistinct secondary venation.

Stomata In botany, a stoma (from Greek ''στόμα'', "mouth", plural "stomata"), also called a stomate (plural "stomates"), is a pore found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange. The pore is bor ...

occur in

areole In botany, areoles are small light- to dark-colored bumps on cacti out of which grow clusters of spines. Areoles are important diagnostic features of cacti, and identify them as a family distinct from other succulent plants. Gordon Rowley - W ...

s, and have very wrinkly subsidiary cells. Both leaf surfaces are covered in

trichome Trichomes (); ) are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a pla ...

bases, and the undersurface is covered in

cuticular A cuticle (), or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non- homologous, differing in their origin, structu ...

papillae.

Taxonomy

Fossil leaves were found at the Newvale Mine, Waimumu Coalfield,

Southland District Southland District is a Districts of New Zealand, territorial authority district in New Zealand that covers the south of the South Island as well as Stewart Island, Stewart Island/Rakiura. History Southland District was formed through the 1989 lo ...

(), in a thin

leaf litter Plant litter (also leaf litter, tree litter, soil litter, litterfall or duff) is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that have fallen to the ground. This detritus or dead organic material and its constituent ...

bed located in a seam of the middle Gore Lignite Measures. ''B. novae-zelandiae'' was first published in 2010. The specific epithet refers to

, where the fossils were found. The fossils are assigned to

Banksieae The Grevilleoideae are a subfamily of the plant family Proteaceae. Mainly restricted to the Southern Hemisphere, it contains around 46 genus, genera and about 950 species. Genera include ''Banksia'', ''Grevillea'', and ''Macadamia''. Descriptio ...

based on several structural grounds, including brachyparacytic stomata, a trichome base architecture unique to Banksieae, "banksioid"

venation Venation may refer to: * Venation (botany), the arrangement of veins in leaves * Wing venation, the arrangement of veins in insect wings See also * * Vernation Vernation (from ''vernal'' meaning ''spring'', since that is when leaves spring forth ...

, and the pinnate leaf lobes. Within Banksieae they are assigned to genus ''Banksia'' because of their cuticular papillae and the division of the leaves into triangular lobes all the way back to the midrib, neither of which occurs in any other Banksieae genus. (Before the 2007 transfer of ''

Dryandra ''Banksia'' ser. ''Dryandra'' is a series of 94 species of shrub to small tree in the plant genus ''Banksia''. It was considered a separate genus named ''Dryandra'' until early 2007, when it was merged into ''Banksia'' on the basis of extensiv ...

'' into ''Banksia'', it was realised that there was no way to distinguish these two genera based solely on foliar characters, and so fossil leaves were classified into the

form genera Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncertainty; the goal of s ...

Banksieaephyllum ''Banksieaephyllum'' is a plant genus that encompasses organically preserved fossil leaves that can be attributed to the Proteaceae tribe Banksieae, but cannot be attributed to a genus. Before 1950, many fossil leaves were attributed to the gen ...

'' and ''

Banksieaeformis ''Banksieaeformis'' is a genus that encompasses plant species only known from fossil leaves that can be attributed to the Proteaceae tribe Banksieae, but cannot be attributed to an extant (living) genus. Unlike those classified in the related gen ...

''. Now, however, they may simply be assigned to ''Banksia''.) Although the cuticular papillae are regarded as evidence that the species belongs to ''Banksia'', their unusual structure, together with some ornamentation of the trichome bases, and the absence of any features of extant ''Banksia'' recognised as derived, suggests that ''B. novae-zelandiae'' is basal to all extant ''Banksia'' species; that is, it belongs to the

stem group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...

of ''Banksia''.

Habitat

The leaf litter bed in which ''B. novae-zelandiae'' was found is regarded as of late

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 the ...

to early

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

origin (), and is thought to have accrued in

swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

s associated with a coastal

delta Delta commonly refers to: * Delta (letter) (Δ or δ), a letter of the Greek alphabet * River delta, at a river mouth * D (NATO phonetic alphabet: "Delta") * Delta Air Lines, US * Delta variant of SARS-CoV-2 that causes COVID-19 Delta may also re ...

. The bed mainly contains species with

sclerophyllous Sclerophyll is a type of vegetation that is adapted to long periods of dryness and heat. The plants feature hard leaves, short internodes (the distance between leaves along the stem) and leaf orientation which is parallel or oblique to direct ...

leaves, with no broad-leaved

rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...

element in evidence, suggesting a

heath A heath () is a shrubland habitat found mainly on free-draining infertile, acidic soils and characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great Britain—a cooler ...

-like environment. The vegetation has been interpreted as growing in a warm and constantly wet climate, and the extensive beds of

lignite Lignite, often referred to as brown coal, is a soft, brown, combustible, sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35%, and is considered the lowest rank of coal due to its relatively low heat ...

in the area suggest an area with poor drainage.

Biogeography

''Banksia novae-zelandiae'' encompasses the first fossil ''Banksia'' material found outside Australia. It shows that the ''Banksia'' lineage once occurred in

, but because the species is regarded as belonging to the stem group, it does not contradict previous evidence suggesting that the

crown group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...

of ''Banksia'' arose in

southwest Australia Southwest Australia is a biogeographic region in Western Australia. It includes the Mediterranean-climate area of southwestern Australia, which is home to a diverse and distinctive flora and fauna. The region is also known as the Southwest Aus ...

some time after the

Paleogene The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...

. Under the long-held view that the New Zealand flora has a

Gondwanan Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...

element that has survived there at least since the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

, the presence of ''B. novae-zelandiae'' in New Zealand can be adequately explained by

vicariance Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...

. It is harder to reconcile it with the recent claim that New Zealand was completely submerged in the late Oligocene, as this would require the unlikely (but possible) dispersal of seeds across thousands of kilometers of ocean.

References

{{DEFAULTSORT:Banksia novae-zelandiae novae-zelandiae Prehistoric angiosperms Flora of the South Island Miocene plants Oligocene plants Extinct plants of New Zealand