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 to over . 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. 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 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. +SpeciesLocationAgeNotesImageWeltrichia alfrediiRomaniaEarly Jurassic (Sinemurian)About 120 mm in diameterWeltrichia alpinaGermanyLate TriassicAbout 54 mm in diameterWeltrichia antoniiRomaniaEarly Jurassic (Sinemurian)About 100 mm in diameter, with only 9/10 rays, has the lowest number of rays of any speciesWeltrichia ayuquilianaMexicoMiddle JurassicAround 60 mm in diameterWeltrichia daohugouensisChinaMiddle JurassicAround 100 mm in diameterWeltrichia fabreiFranceLate Triassic-Early JurassicOnly known from fragmentary remainsWeltrichia givulescuiRomaniaEarly Jurassic (Sinemurian)Maximum of 100 mm in diameterWeltrichia harrisianaIndiaMiddle JurassicApproximately 120–150 mm in diameterWeltrichia hirsutaIranEarly JurassicApproximately 130–140 mm in diameterWeltrichia huangbanjingouensisChinaLate Jurassic/Early CretaceousOnly central cup is preservedWeltrichia johannaeRomaniaEarly Jurassic (Sinemurian)70 mm in diameterWeltrichia maldaensisIndiaLate Jurassic70 mm in diameterWeltrichia microdigitataMexicoMiddle JurassicDiameter of only 30 mm, making it smallest known speciesWeltrichia mirabilis (type)GermanyEarly JurassicApproximately 100 mm in diameterWeltrichia mixtequensisMexicoMiddle JurassicDiameter of 160 mmWeltrichia oolithicaItalyLate Jurassic70–80 mm in diameter, holotype specimen currently unlocatedWeltrichia pectenEnglandMiddle JurassicTypically 100–120 mm in diameter. Has been suggested to be synonymous with Weltrichia spectabilis and Weltrichia whitbiensis.Weltrichia primaevaIranEarly JurassicOnly known from large (over 60 mm in length) ray fragments with a complex morphologyWeltrichia santalensisIndiaMiddle-Late JurassicWith a diameter of 220–230 mm, it is one of the largest species in the genusWeltrichia 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 gigasWeltrichia 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 diameterWeltrichia whitbiensisEnglandMiddle JurassicAround 120–130 mm in diameter. Has been suggested to be synonymous with Weltrichia pecten and Weltrichia spectabilis.Weltrichia magnaMexicoMiddle JurassicAround 226 mm in diameter.Weltrichia xochitetliiMexicoMiddle JurassicApproximately 30–45 mm in diameter
References