Mesocalamites taitianus (KIDST. et JONGM.) HIRMER , 1927

Cleal, Christopher J., Strullu-Derrien, Christine & Spencer, Alan R. T., 2024, Early Coal Swamp Vegetation From The Serpukhovian Lower Clackmannan Group Of Scotland, Fossil Imprint 80 (1), pp. 35-67 : 44-45

Mesocalamites taitianus (KIDST. et JONGM.) HIRMER, 1927

Text-fig. 5e

1915 Calamites taitianus KIDST. et JONGM. , pl. 147, fig. 5, pl. 148, fig. 1, pl. 149, figs 1–5.

1917 Calamites taitianus KIDST. et JONGM. ; Kidston and Jongmans, p. 195.

1927 Mesocalamites taitianus (KIDST. et JONGM.) HIRMER , p. 382.

1969 Calamites taitianus KIDST. et JONGM. ; Crookall, p. 625, pl. 112, figs 1–3, pl. 113, figs 1, 2.

1969 Calamites cistiformis STUR ; Crookall, p. 623, pl. 111, figs 1, 2.

1969 Calamites ramifer STUR ; Crookall, p. 627, pl. 116, figs 2–4, pl. 117, fig. 1.

1969 Archaeocalamites radiatus (BRONGN.) STUR ; Crookall, p. 611, pl. 110, figs 2, 3 (non figs 1, 4).

D e s c r i p t i o n. Stems with more-or-less straight longitudinal ribs, 1–2 mm wide, with rounded end and small indistinct distal tubercle. Weakly marked nodes at intervals of up to 70 mm, with ribs mostly passing directly over them but occasionally offset. Branch scars 7–22 mm in size, circular to transversely oval, widely distributed along stem, with no more than two at each node. Ribs tend to be deflected around scars.

R e m a r k s. This is one of the best-documented Mesocalamites species based on the material from the Bilston Burn site in Midlothian, and differs from M. haueri in having much finer longitudinal ribbing and occasional prominent branch scars. Very similar stems found in close association with M. taitianus were described by Crookall (1969) as Calamites cistiformis and Calamites ramifer , without giving any reason for separating them taxonomically other than the latter two have smaller and more widely-spaced branch scars. Since the branch scars distribution in M. taitianus is very variable, this is not a reliable character. Since the epithets cistiformis and ramifer were published before that of M. taitianus ( Stur 1877) one of the former names might take precedence but, until the types of the former have been more fully documented, the latter name has been retained here.

The specimens figured by Crookall (1969) as Archaeocalamites radiatus from the Limestone Coal Formation are very similar to M. taitianus except that the ribs appear to cross the nodes more consistently. Given that this is also a variable character in M. taitianus , the latter name has been used for these specimens.

O c c u r r e n c e s. Ther Limestone Coal Formation, between the Johnstone Shell Bed and the coal-bearing interval above the Black Metals Band, and the Upper Limestone Formation, mainly from below Castlecary Limestone at Bilston Burn.

Figures

Text-fig. 5. a: Lepidostrobophyllum veltheimianum (GEINITZ) STRULLU-DERRIEN, CLEAL, DUCASSOU, A.R.T.SPENCER, STOLLE et LESHYK; New Braidbar Quarry, Giffnock, East Renfrewshire; below Orchard Limestone, Upper Limestone Formation; BGS Kidst.2625. b: Lepidophloios grangeri B.A.THOMAS; Craw Coal, No. 4 Mine, Grange, Boness, Linlithgowshire; Limestone Coal Formation; BGS Kidst.1828. c: Stigmaria stellata (GÖPP.) GÖPP.; above Steam Coal, Stripeside Pit, Herbertshire Colliery, Denny, Stirlingshire;