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Weltrichia

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Weltrichia
Temporal range: Late Triassic–Late Jurassic
Drawing of Weltrichia mirabilis
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Order: Bennettitales
Family: Williamsoniaceae
Genus: Weltrichia
Braun
Type species
Weltrichia mirabilis
Braun
Species

See text

Weltrichia is a genus belonging to the extinct seed plant group Bennettitales. It is a form genus representing flower-like male pollen-producing organs. It is associated with the female ovulate cone Williamsonia.

Description

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Diagram of Weltrichia givulescui. Labels: CFR Centrifugal ray; CPR Centripetal ray; MR Median ridge; FS Fibrous strand; PS Pollen sac position (in this case, pollen sac attachment); CC Central cup; RBA Resin (resinous) body or attractant; ST Stalk

Although the morphology of Weltrichia is highly variable, the overall morphology consists of a central cup-like structure surrounded by a number of radially symmetrical outward projecting rays, to which are attached bivalve-shaped pollen sacs/synangia. The number of rays varies from 9/10 to 30, depending on the species, and the total diameter from 3 centimetres (1.2 in) to over 20 centimetres (7.9 in). Both the cup and rays usually (but not always) have substantial thickness, in some of the thicker species the structure is noticeably woody. The pollen is monocolpate and elliptical. In some species, additional rays project over the central cup, and attractants/resinous substances are present within the cup. The rays also sometimes have ridges, trichomes, appendages, striae and/or unipinnate (pedicellate) pollen sacs present. Species of Weltrichia appear to have primarily been wind pollinated, though some species may have been pollinated by insects, such as beetles. They were borne by the same plants that also bore female ovulate cones assigned to Williamsonia.[1] It is unclear whether the parent plants were monoecious (having both structures on one plant) or dioecious (where each plant only has one gender of reproductive organ). At least some bearers of Weltrichia, such as Kimuriella from the Late Jurassic of Japan were low growing divaricately branching shrubs with a maximum height of 2–3 metres, while others such as Williamsonia gigas may have been more cycad-like in morphology.[2]

Distribution

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Weltrichia is known from Asia, Europe, and North America, as well as India (which formed part of the separate landmass Gondwana at the time), spanning from the Late Triassic to the Late Jurassic/Early Cretaceous.[1]

Species

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After Popa (2019)[1] and subsequent literature.

Species Location Age Notes Image
Weltrichia alfredii Romania Early Jurassic (Sinemurian) About 120 mm in diameter
Weltrichia alpina Germany Late Triassic About 54 mm in diameter
Weltrichia antonii Romania Early Jurassic (Sinemurian) About 100 mm in diameter, with only 9/10 rays, has the lowest number of rays of any species
Weltrichia ayuquiliana Mexico Middle Jurassic Around 60 mm in diameter
Weltrichia daohugouensis China Middle Jurassic Around 100 mm in diameter
Weltrichia fabrei France Late Triassic-Early Jurassic Only known from fragmentary remains
Weltrichia givulescui Romania Early Jurassic (Sinemurian) Maximum of 100 mm in diameter
Weltrichia harrisiana India Middle Jurassic Approximately 120–150 mm in diameter
Weltrichia hirsuta Iran Early Jurassic Approximately 130–140 mm in diameter
Weltrichia huangbanjingouensis China Late Jurassic/Early Cretaceous Only central cup is preserved
Weltrichia johannae Romania Early Jurassic (Sinemurian) 70 mm in diameter
Weltrichia maldaensis India Late Jurassic 70 mm in diameter
Weltrichia microdigitata Mexico Middle Jurassic Diameter of only 30 mm, making it smallest known species
Weltrichia mirabilis (type) Germany Early Jurassic Approximately 100 mm in diameter
Weltrichia mixtequensis Mexico Middle Jurassic Diameter of 160 mm
Weltrichia oolithica Italy Late Jurassic 70–80 mm in diameter, holotype specimen currently unlocated
Weltrichia pecten England Middle Jurassic Typically 100–120 mm in diameter. Has been suggested to be synonymous with Weltrichia spectabilis and Weltrichia whitbiensis.[2]
Weltrichia primaeva Iran Early Jurassic Only known from large (over 60 mm in length) ray fragments with a complex morphology
Weltrichia santalensis India Middle-Late Jurassic With a diameter of 220–230 mm, it is one of the largest species in the genus
Weltrichia setosa England Middle Jurassic Typically 120 mm in diameter.
Weltrichia sol England Middle Jurassic One of the largest species, at 170–200 mm in diameter, associated with the female cone Williamsonia gigas and the leaves Zamites gigas
Weltrichia spectabilis England Middle Jurassic Central cup 40 mm in diameter and rays 30-50 mm in length, which bear apical filiform whiskers, which can reach 30-60 mm in length.[1] Has been suggested to be synonymous with Weltrichia pecten and Weltrichia whitbiensis.[2]
Weltrichia steierdorfensis Romania Early Jurassic (Sinemurian) Around 105–120 mm in diameter
Weltrichia whitbiensis England Middle Jurassic Around 120–130 mm in diameter.[1] Has been suggested to be synonymous with Weltrichia pecten and Weltrichia spectabilis.[2]
Weltrichia magna[3] Mexico Middle Jurassic Around 226 mm in diameter.
Weltrichia xochitetlii[4] Mexico Middle Jurassic Approximately 30–45 mm in diameter

References

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  1. ^ a b c d e Popa, Mihai Emilian (December 2019). "Review of the bennettitalean genus Weltrichia". Journal of Palaeogeography. 8 (1): 12. doi:10.1186/s42501-019-0023-9. ISSN 2524-4507.
  2. ^ a b c d Pott, Christian; Takimoto, Hideo (2022-04-01). "Kimuriella gen. nov. (Bennettitales), a Whole-Plant Bennettite from the Oxfordian (Upper Jurassic) Tochikubo Formation of Shidazawa, Minamisōma, Fukushima Prefecture, Northeast Japan". Paleontological Research. 26 (2). doi:10.2517/PR200020. ISSN 1342-8144. S2CID 247960229.
  3. ^ Guzmán-Madrid, Diana Silvia; Velasco de León, María Patricia (June 2021). "Weltrichia magna sp. nov., a new record for the Middle Jurassic of Oaxaca, México". Acta Palaeobotanica. 61 (1): 95–106. doi:10.35535/acpa-2021-0005. Archived (PDF) from the original on Jul 1, 2021.
  4. ^ Lozano-Carmona, Diego E.; Corro-Ortiz, Marcos Germán; Morales, René Luis; Velasco-de León, María Patricia (June 2021). "Weltrichia xochitetlii sp. nov. (Bennettitales) from the Middle Jurassic of northwestern oaxaca, Mexico: First paleobotanical evidence from the Tecomazúchil Formation". Journal of South American Earth Sciences. 108: 103230. doi:10.1016/j.jsames.2021.103230.