Weltrichia Explained

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

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 3cm (01inches) to over 20cm (10inches). 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.

Distribution

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.

Species

After Popa (2019) and subsequent literature.

!Species!Location!Age!Notes!Image
Weltrichia alfrediiRomaniaEarly Jurassic (Sinemurian)About 120 mm in diameter
Weltrichia alpinaGermanyLate TriassicAbout 54 mm in diameter
Weltrichia antoniiRomaniaEarly Jurassic (Sinemurian)About 100 mm in diameter, with only 9/10 rays, has the lowest number of rays of any species
Weltrichia ayuquilianaMexicoMiddle JurassicAround 60 mm in diameter
Weltrichia daohugouensisChinaMiddle JurassicAround 100 mm in diameter
Weltrichia fabreiFranceLate Triassic-Early JurassicOnly known from fragmentary remains
Weltrichia givulescuiRomaniaEarly Jurassic (Sinemurian)Maximum of 100 mm in diameter
Weltrichia harrisianaIndiaMiddle JurassicApproximately 120–150 mm in diameter
Weltrichia hirsutaIranEarly JurassicApproximately 130–140 mm in diameter
Weltrichia huangbanjingouensisChinaLate Jurassic/Early CretaceousOnly central cup is preserved
Weltrichia johannaeRomaniaEarly Jurassic (Sinemurian)70 mm in diameter
Weltrichia maldaensisIndiaLate Jurassic70 mm in diameter
Weltrichia microdigitataMexicoMiddle JurassicDiameter of only 30 mm, making it smallest known species
Weltrichia mirabilis (type)GermanyEarly JurassicApproximately 100 mm in diameter
Weltrichia mixtequensisMexicoMiddle JurassicDiameter of 160 mm
Weltrichia oolithicaItalyLate Jurassic70–80 mm in diameter, holotype specimen currently unlocated
Weltrichia pectenEnglandMiddle JurassicTypically 100–120 mm in diameter. Has been suggested to be synonymous with Weltrichia spectabilis and Weltrichia whitbiensis.[2]
Weltrichia primaevaIranEarly JurassicOnly known from large (over 60 mm in length) ray fragments with a complex morphology
Weltrichia santalensisIndiaMiddle-Late JurassicWith a diameter of 220–230 mm, it is one of the largest species in the genus
Weltrichia setosaEnglandMiddle JurassicTypically 120 mm in diameter.
Weltrichia solEnglandMiddle JurassicOne of the largest species, at 170–200 mm in diameter, associated with the female cone Williamsonia gigas and the leaves Zamites gigas
Weltrichia spectabilisEnglandMiddle JurassicCentral 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. Has been suggested to be synonymous with Weltrichia pecten and Weltrichia whitbiensis.
Weltrichia steierdorfensisRomaniaEarly Jurassic (Sinemurian)Around 105–120 mm in diameter
Weltrichia whitbiensisEnglandMiddle JurassicAround 120–130 mm in diameter. Has been suggested to be synonymous with Weltrichia pecten and Weltrichia spectabilis.
Weltrichia magna[3] MexicoMiddle JurassicAround 226 mm in diameter.
Weltrichia xochitetlii[4] MexicoMiddle JurassicApproximately 30–45 mm in diameter

Notes and References

  1. Popa . Mihai Emilian . December 2019 . Review of the bennettitalean genus Weltrichia . Journal of Palaeogeography . en . 8 . 1 . 12 . 10.1186/s42501-019-0023-9 . 2524-4507. free .
  2. 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 . 10.2517/PR200020 . 1342-8144 . 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 . 10.35535/acpa-2021-0005. free . live . https://web.archive.org/web/20210701144924/https://acpa.botany.pl/pdf-138846-66413?filename=Weltrichia%20magna%20sp..pdf . 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 . en . 108 . 103230 . 10.1016/j.jsames.2021.103230.