taxonID	type	description	language	source
03CC8780E362360B7F980B57FAC2FE82.taxon	description	R e m a r k s. Oberste-Brink (1914) originally established the name Anisopteris as a Section of the genus Rhacopteris SCHIMP., 1869. Oberste-Brink (1914) noted that Anisopteris was only known from the “ Culm ” (Mississippian), whilst the other Section, Eurhacopteris, was only known from the Pennsylvanian (although following Turland et al. (2018) the Section name Eurhacopteris is not valid as it included the type of the genus Rhacopteris and its epithet does not repeat the generic name unaltered). Due to the stratigraphic grouping, Walton (1926) believed that the division was biased and that it should not be adopted. However, Hirmer (1940) emended the diagnosis and elevated the name Anisopteris to full generic rank, asserting that the division was not merely stratigraphic, with the Lower Carboniferous species Rhacopteris transitionis excluded from Anisopteris. It was also reported that fertile fronds are unknown in Rhacopteris, while Anisopteris includes fertile material (Oberste-Brink 1914, Hirmer 1940). A type species for Anisopteris was only designated later when Boureau and Doubinger (1975) selected Anisopteris inaequilatera (GÖPP.) HIRMER, 1940. Anisopteris is not a nomenclatural synonym of Rhacopteris SCHIMP., 1869 as these two generic names are heterotypic (with Rhacopteris elegans (ETTINGSH.) SCHIMP., 1869 given as the type species of Rhacopteris; Kidston 1890). The taxa are considered morphologically distinct, with Anisopteris pinnules defined as strikingly asymmetrical, with no trace of a central vein (Oberste-Brink 1914, Boureau and Doubinger 1975).	en	Hayes, Peta Angela, Pearson, Hugh Lance (2024): Anisopteris Shuteana Sp. Nov., A Fertile Adpression Fossil From The Mississippian (Lower Carboniferous) Of Teilia Quarry, North Wales, Uk. Fossil Imprint 80 (1): 125-134, DOI: 10.37520/fi.2024.011
03CC8780E362360D7C5B0E16FA8CF8F7.taxon	description	Text-figs 1 – 3 H o l o t y p e. V 25790, Palaeobotany Collections, NHMUK. P l a n t F o s s i l N a m e R e g i s t r y N u m b e r. PFN 003401 (for the new species). E t y m o l o g y. This species is named in honour of Cedric H. Shute, former Curator of Palaeobotany at the Natural History Museum, London. T y p e l o c a l i t y. Teilia Quarry, Gwaenysgor, Flintshire, North Wales, United Kingdom [SJ 0793 8137]. T y p e h o r i z o n. Teilia Formation, Craven Group. A g e. Brigantian, Visean, Middle Mississipian (lower Carboniferous). D i a g n o s i s. Rachis covered with longitudinal striations spaced approx. 0.1 mm apart. Primary rachis width approx. 2.5 mm, narrowing slightly to 2 mm after the first dichotomy. Angle of divergence of first dichotomy narrow acute; angle of divergence of subsequent repeated dichotomies wide acute to obtuse. Ultimate rachises up to 0.6 mm wide. Clusters of pedicellate sporangia attached terminally on ultimate rachises. Sporangia narrow ovate in outline, each sporangium roughly symmetrical and approx. 2.1 mm in length and 0.8 mm in width. D e s c r i p t i o n. The specimen is a fertile portion of a plant, with the maximum dimensions of this fragmentary specimen approx. 6 cm in length and 3 cm in width (Text-fig. 1 a, b). There is no attachment to a sterile section of frond bearing pinnules. The rachis appears slightly flexuous. The primary rachis is approx. 2.5 mm wide, narrowing slightly to 2 mm after the first dichotomy, which is approx. 2 cm above the base of the fossil, with ultimate rachises of up to 0.6 mm wide. The rachis is covered with longitudinal striations spaced approx. 0.1 mm apart (Text-fig. 2 a, 3 a). The first dichotomy preserved in this specimen is narrow acute (42 °). The rachis then dichotomizes at least two more times at an angle of divergence of 70 – 110 ° (mean 94 °) (Text-fig. 2 b). The irregularity of the branching preserved in this adpression fossil is suggestive of a three-dimensional branching axis rather than a two-dimensional frond. The sporangia are attached to the ultimate rachises in clusters of at least four, but the state of preservation does not allow them to be counted precisely (Text-fig. 2 b). The majority of the pedicellate sporangia observed appear pendent (Text-fig. 2 c, d). The pedicel appears to be approx. 0.5 mm long and 0.1 mm wide (Text-fig. 2 d). The sporangia are narrow ovate in outline, with an average length: width ratio of approx. 2.5: 1 (Text-fig. 2 b, c, d). Each sporangium appears roughly symmetrical. As a result of the clustering and overlapping of the sporangia precise measurement of each sporangium is difficult. The sporangia appear to range in size from 2.0 to 2.7 mm long (mean 2.1 mm) and 0.7 to 1.0 mm wide (mean 0.8 mm) (Text-fig. 2 b, c, d). The surfaces of the sporangia are covered with fine striations (Text-fig. 3 b). A d d i t i o n a l m a t e r i a l. V 25777. Specimens that appear similar to these fertile organs have been found in association with sterile fronds, but organic connection has not been observed (Text-fig. 4 a, b). D i s c u s s i o n. The report of Benson’s collecting recording the association of many specimens of Rhacopteris fronds, now assigned to Anisopteris, with this fertile material at Teilia Quarry supports the assignment of this species to Anisopteris, but no sterile fronds have been found in organic connection with this fertile specimen. This species is assigned to the genus Anisopteris on the basis of observed similarities with Anisopteris fertilis (J. WALTON) HIRMER, 1940, a single specimen that was also collected from Teilia Quarry and originally described as Rhacopteris fertilis WALTON, 1926 (Text-fig. 4 c, d). Hirmer (1940) included R. fertilis within Anisopteris due to its similarity to the fertile frond section of Anisopteris lindseaeformis (BUNBURY) HIRMER, 1940, the only species which includes both sterile and fertile material since Kidston (1923) synonymized Rhacopteris paniculifera STUR, 1875 with Rhacopteris lindseaeformis (BUNBURY) KIDSTON in Patton (1884) and which Hirmer transferred to Anisopteris remarking on the asymmetry of the sterile pinnules. There are therefore two fertile species of Anisopteris available for comparison with A. shuteana.	en	Hayes, Peta Angela, Pearson, Hugh Lance (2024): Anisopteris Shuteana Sp. Nov., A Fertile Adpression Fossil From The Mississippian (Lower Carboniferous) Of Teilia Quarry, North Wales, Uk. Fossil Imprint 80 (1): 125-134, DOI: 10.37520/fi.2024.011
