Selaginella wangxinii A. R. Schmidt & L. Regalado, 2022
publication ID |
https://doi.org/10.3372/wi.52.52203 |
persistent identifier |
https://treatment.plazi.org/id/038887E3-FFB7-F212-FCED-EF8CFEA90BEA |
treatment provided by |
Felipe |
scientific name |
Selaginella wangxinii A. R. Schmidt & L. Regalado |
status |
sp. nov. |
Selaginella wangxinii A. R. Schmidt & L. Regalado , sp. nov.
Holotype: PB23101 [ Fig. 14], Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences. – Fig. 1H; 14 (only specimen available).
Diagnosis — Axes compressed. Trophophylls dimorphic. Dorsal trophophylls distant, adpressed, lanceolate, non-carinate, base decurrent, apex aristate, margins sparsely dentate. Ventral trophophylls distant, spreading, ovate-lanceolate, non-carinate, apex acute to obtuse, margins sparsely denticulate to dentate. Strobili terminal, compact, bilateral, dorsiventrally somewhat complanate, resupinate. Dorsal sporophylls close, ascending, conduplicate, lanceolate, carinate, base slightly decurrent, apex attenuate, margins sparsely dentate to sometimes ciliate at distal basiscopic and acroscopic sides; sporophyll-pteryx nearly complete, dentate. Ventral sporophylls close, adpressed, broadly ovate-lanceolate, carinate, apex attenuate, margins sparsely dentate-ciliate. Sporangia suborbicular. Megaspores proximally echinate. Microspores proximally rugulate.
Description — Rhizophores not preserved. Axes compressed. Trophophylls dimorphic. Axillary trophophylls not preserved. Dorsal trophophylls distant, adpressed, 0.7–0.8 × 0.3–0.4 mm, lanceolate, non-carinate, base decurrent apex aristate, margins sparsely dentate, teeth 20–40 µm long. Ventral trophophylls distant, spreading, ascending, 0.8–1.2 × 0.4–0.5 mm, ovate-lanceolate, non-carinate, base not seen, apex acute to obtuse, margins sparsely denticulate to dentate, teeth 10–50 µm long. Epidermis of dorsal and ventral trophophylls poorly preserved. Strobili terminal, compact, bilateral, dorsiventrally somewhat complanate, resupinate 5.4–6.3 × 0.8–1.2 mm ( Fig. 14A, B). Sporophylls dimorphic. Dorsal sporophylls close, ascending, 24–26 per strobilus, 0.9–1.1 × 0.2–0.3 mm, lanceolate, non-carinate, base slightly decurrent, acute at apex, margins sparsely dentate to sometimes ciliate at distal basiscopic and acroscopic sides, teeth or cilia 40–100 µm long ( Fig. 1H; 14D, F); sporophyll-pteryx nearly complete, with margins dentate-ciliate similar to sporophyll margins ( Fig. 14D, F). Ventral sporophylls close, adpressed, 26–28 per strobilus, 0.9–1.0 × 0.3–0.4 mm, broadly ovate-lanceolate, carinate, base not seen, apex attenuate, margins sparsely dentate or short-ciliate, cilia 20–80 µm long µm long ( Fig. 1H; 14C, E). Epidermis cells of ventral sporophylls elongate, with long axes orientated uniformly parallel to carina ( Fig. 14E). Sporangia suborbicular, 250–350 × 280–320 µm, with uniform isodiametric cells bearing thick anticlinal walls ( Fig. 14G). At least 1 megasporangium containing 2 megaspores present proximally in strobilus ( Fig. 14I). Megaspores 160–190 µm in diam., proximally echinate ( Fig. 14J). Microspores 25–30 µm in diam., proximally rugulate ( Fig. 14H).
Remarks — The overall appearance and morphology of strobili and sporophylls of Selaginella wangxinii are very similar to those seen in S. patrickmuelleri . Both taxa share the general shape of the dorsal and ventral sporophylls, the shape of the sporophyll apices, bases and margins and the presence of carinae. However, they differ from each other in the size of the strobili, the shape of the sporophyll-pteryx and ornamentation of the megaspores (see remarks under S. patrickmuelleri for details).
The morphology of Selaginella wangxinii resembles three extant species, namely S. chrysocaulos , S. ciliaris and S. elegantissima , all of which are characterized by dorsal sporophylls with an incomplete sporophyll-pteryx (ending midway to apex) ( Dixit 1992; Zhang & al. 2013; Johari & Singh 2017), which is mostly entire-margined in S. elegantissima ( Van Alderwerelt van Rosenburgh 1915) , whereas the fossil has a nearly complete sporophyll-pteryx with dentate-ciliate margins ( Fig. 1H; 14D, F). Additionally, S. chrysocaulos and S. elegantissima have verrucate microspore ornamentations ( Van Alderwerelt van Rosenburgh 1915; Zhou & al. 2015a) and S. ciliaris has baculate microspores, which differ from the rugulate pattern observed in the fossil ( Fig. 14H).
Etymology — The specific epithet honours Professor Xin Wang (Nanjing), who discovered the fossil in the collection of the Nanjing Institute of Geology and Palaeontology.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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