Biology:Kimuriella
Kimuriella (und) (named after Tatsuaki Kimura Japanese: 木村 達明) is a monotypic whole-plant genus of williamsoniacean bennettitalean from the Tochikubo Formation of Fukushima, northeast Japan. The type species is Kimuriella densifolia, known from various specimens comprising leaf-bearing branches and disarticulated leaves of the Zamites nipponicus-type, articulated and disarticulated mature and maturing seed cone of the Williamsonia-type, and articulated and disarticulated male reproductive organs of the Weltrichia-type.
Etymology
The generic name (Kimuriella und) is after Tatsuaki Kimura (und) (Japanese: 木村 達明 und) using the diminutive Latin suffix -ella (a commonly used suffix in binomial nomenclature named after a person) "in honour of his excellent contributions to Japanese palaeobotany".[1] The specific name (densifolia und) is from the Latin word densus (Latin: dēnsus und) (specifically the plural form, densi (Latin: dēnsī und)), (which translates to dense) and the Latin folium (und) (specifically the plural form, folia (und)) (which translates to leaf) in reference to the dense and stiff foliage of the plant.[1]
Description
Pott and Takimoto (2022) investigated 42 slabs collected from the Tochikubo Formation, six of which contained articulated plant remains. Of the specimens within these slabs, they designated MM-000923a as the holotype (its counterpart being MM-000927a) with five other specimens being designated as epitypes (disarticulated male organs MM-000923b, MM-000927b; articulated foliage around a developing female organ MM-000927b; disarticulated male organ MM-000904). The holotype preserves a branch with female organ and seed cone terminating growth intervals.[1]
The authors also note that previously described material from the Isokusa Formation shares a striking resemblance to Kimuriella in both male organs and foliage, the foliage — initially described as cfr. Zamites feneonis[2] — was concluded to be conspecific with Zamites nipponicus by Kimura and Ohana (1988a).[3] Though, no examination of this specimen was made and the authors leave this assignment as tentative.[1]
Palaeobiology
Kimuriella preserves similar growth structures to other bennettitaleans, including divaricately branched growth with the reproductive organs growing on the terminal end of the main axis, later inducing lateral branching during the next growth period (the period probably being seasonally or annually).[1][4] They described the overall architecture of the plant as "a low-growing shrub-like plant probably up to 2–3 m tall... [with] divaricately branched axes". One thing to note is that the fossils (such as the holotype) show that only one female reproductive organ is receptive per active branch with the expected other lateral branch being missing.[1]
Palaeoecology
The Tochikubo Formation, from which Kimuriella is known,[1] has been interpreted as a mostly non-marine fluvial to near-shore and low-energy lake deposit, with the facies of the formation changing in ascending order from fluvial to lake association, flood plain, alluvial fan into a delta-front coastal environment in its uppermost part.[1]
The authors that described the plant state that it "probably formed tangled shrub thickets in brackish to tidal mudflat areas or delta settings colonising ephemeral isles or sand bars that were regularly flooded such as in mangroves".[1]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Pott, Christian; Takimoto, Hideo (1 Apr 2022). "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. https://bioone.org/journals/paleontological-research/volume-26/issue-2/PR200020/Kimuriella-gen-nov-Bennettitales-a-Whole-Plant-Bennettite-from-the/10.2517/PR200020.full. Retrieved 2 August 2026.
- ↑ Ôishi, Saburô (31 Mar 1940). "The Mesozoic Floras of Japan". The Hokkaido Imperial University 5 (2-4): 123-480. https://hdl.handle.net/2115/35805. Retrieved 2 August 2026.
- ↑ Kimura, Tatsuaki; Ohana, Tamiko (22 Sep 1988). "Late Jurassic plants from the Tochikubo Formation (Oxfordian), Somanakamura Group, in the outer zone of northeast Japan Ⅰ". Bulletin of the National Science Museum. Series C, Geology & paleontology 14 (3). https://ndlsearch.ndl.go.jp/books/R100000039-I12199511. Retrieved 2 August 2026.
- ↑ Pott, Christian; McLoughlin, Stephen (24 May 2014). "Divaricate growth habit in Williamsoniaceae (Bennettitales): unravelling the ecology of a key Mesozoic plant group". Palaeobio Palaeoenv 94: 307–325. doi:10.1007/s12549-014-0157-9. https://link.springer.com/article/10.1007/s12549-014-0157-9. Retrieved 24 December 2025.
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