TAXON 62 (6) • December 2013: 1343–1345
Doweld • (2244–2245) Conserve Cladophlebis and Pecopteris denticulata
(2244–2245) Proposals to conserve the names Cladophlebis with a conserved type and Pecopteris denticulata (Cladophlebis denticulata) against P. ligata (fossil Pteridophyta: Osmundopsida) Alexander B. Doweld National Institute of Carpology (Gaertnerian Institution), 21 Konenkowa Street, 127560, Moscow, Russian Federation;
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DOI: http://dx.doi.org/10.12705/626.32 (2244) Cladophlebis Brongn. in d’Orbigny, Dict. Univ. Hist. Nat. 13: 74. 30 Jun–7 Jul 1849, nom. cons. prop. Typus: C. denticulata (Brongn.) Schimp. (Pecopteris denticulata Brongn.), typ. cons. prop. (2245) Pecopteris denticulata Brongn., Hist. Vég. Foss. 1: 301. 6 Jan 1834, nom. cons. prop. Typus: Great Britain, Yorkshire, Scarborough; Jurassic (Lower Bajocian) (Mus. Natl. d’Hist. Nat. Paris: MNHN.F.611); [illustrated in Brongniart, l.c.: t. 98, fig. 1a, 1b]. (=) Pecopteris ligata Phillips, Illustr. Geol. Yorkshire: 148. Apr 1829, nom. rej. prop. Typus: Great Britain, Yorkshire, between Red Cliff and Gristhorpe; Jurassic (Oxford Mus. Nat. Hist.) [illustrated in Phillips, l.c.: t. 8, fig. 14] When established in 1849, the genus Cladophlebis was explicitly based on Pecopteris sect. Neuropteroides Brongn. (Hist. Vég. Foss. 1: 320. 17 Feb 1834) (‘Nevropteroides’, Art. 60.5), which was typified by the author (l.c.: 326. 1834) with Pecopteris defrancei Brongn. (‘defrancii ’), a Carboniferous pteridosperm belonging now to the distinct genus Palaeoweichselia Potonié. Cladophlebis in its original 1849 circumscription was a curious mixture of various unrelated species of fossil plants, which have been later re-classified not only into distinct genera, but different orders and even phyla of vascular plants. An analytical synopsis of all species classified under Cladophlebis in 1849 (incl. species from P. sect. Neuropteroides eligible to serve for typification of the genus but not formally combined by Brongniart into Cladophlebis), is given as follows: Carboniferous ferns (Marattiopsida): Acitheca Schimp.: Pecopteris polymorpha Brongn., P. cistii Brongn., and P. pteroides Brongn.; Spiropteris Schimp.: P. miltonii (Artis) Brongn. Carboniferous Pteridospermae: Alethopteris Sternb.: P. beaumontii Brongn.; Callipteridium C.E. Weiss: P. ovata Brongn.; Palaeoweichselia Potonié: P. defrancei Brongn. and P. nestleriana Brongn.; Mixoneura C.E. Weiss: P. obliqua Brongn. Mesozoic (Triassic) ferns (Marattiales): P. sulziana Brongn.; (Protodicksoniales and Osmundales): Eboracia Thomas ex Seward: Cladophlebis lobifolia (Phillips) Brongn. and C. undulata (Lindl. & Hutton) Brongn.; Todites Seward: Cladophlebis williamsonis (Brongn.) Brongn., C. recentior (Phillips) Brongn., C. whitbiensis (Brongn.) Brongn., and C. tenuis (Brongn.) Brongn.; Cladophlebis Brongn. s.str. (remained in current use): C. albertsii (Dunker) Brongn., C. dentata (Lindl. & Hutton) Brongn., C. haiburnensis (Lindl. & Hutton) Brongn., and C. ligata (Phillips) Brongn. It is probably due to such a variable, indefinite circumscription,
that the generic name was very intermittently used in the systematic palaeobotany of the 19th century until Saporta (Paléont. Franç., Pl. Jurass. 1: 298. 1872) adopted it for Mesozoic osmundaceous species. Later he definitely excluded all Palaeozoic taxa (l.c. 4: 357. 1891), since when it has been in general use for mostly Mesozoic fern taxa in palaeobotany and geological stratigraphy (Schimper, Traité Paléontol. Vég. 3: 503. 1874; Seward, Cat. Mesoz. Pl., Jurass. Fl. 1: 134. 1901; Frenguelli in Anales Mus. La Plata, B 2: 1. 1947; Harris, Yorkshire Jurass. Fl. 1: 87. 1961; Kiritchkova in Trudy Vsesoyuzn. Neft. Nauchno-Issl. Geol.-Razved. Inst., Ser. 2, 196: 495. 1962; Herbst in Ameghiniana 8: 265. 1971; Boureau & Doubinger in Boureau, Traité Paléobot. 4(2): 202–246. 1975; Czier in Neues Jahrb. Geol. Palaeontol. Monatsh. 1995(1): 39. 1995; Kiritchkova & al., Fitostratigr. Fl. Jursk. Zap. Sibiri: 72. 2005). This established usage, however, is in contradiction to the nomenclatural type of the generic name coinciding with the type of Pecopteris sect. Neuropteroides, viz. Pecopteris defrancei Brongn., which is a Carboniferous pteridosperm. This problem has already been raised by Lowther (in Taxon 7: 234–235. 1958) who proposed to conserve Saporta’s generic name as a later homonym in current use against mixtural Cladophlebis Brongn. (1849). Although the then Committee for Palaeobotanical Nomenclature was favourable toward the proposal (Mamay in Taxon 8: 125. 1959), the “Comments” in the Report noted that the proposal did not indicate the type of Saporta’s name and recommended that it be held in abeyance and there it apparently has remained and so the problem of the type of Cladophlebis remains unresolved. The nomenclatural confusion can only be solved by conservation of a type of Cladophlebis that conforms to the modern usage of the name for a genus of osmundaceous vegetative foliage of Mesozoic age (Bodor & Barbacka in Palaeoworld 17: 201–214. 2008). In available palaeobotanical literature (1849–1955) I have found two attempts to designate a type of the name, despite its being already typified through being based on Pecopteris sect. Neuropteroides.: 1. C. whitbiensis (Brongn.) Brongn. (≡ Pecopteris whitbiensis Brongn.): this is the earliest attempt known to designate the generic type and was made by Dawson (in Proc. Trans. Roy. Soc. Canada 10(4): 85. 1893), but nevertheless this selection is not appropriate because C. whitbiensis is now considered a synonym of the type of another generic name, Todites, T. williamsonis (Brongn.) Seward (vide Harris, l.c. 1961). Turutanova-Ketova (in Orlov, Osnovy Paleontol. [14]: 604. 1963) followed this type designation. 2. C. albertsii (Dunker) Brongn. (≡ Neuropteris albertsii Dunker, Monogr. Norddeutsch. Wealdenbild. 8, t. 7, fig. 6, 6a. 1846) was later suggested by Andrews (in Bull. U.S. Geol. Surv. 1013: 54. 1955). This name is based on fragmentary, ill-known vegetative foliage from the Lower Cretaceous (Wealden) of North Germany with no signs of any associations with fertile condition; nothing more on its structure and
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Doweld • (2244–2245) Conserve Cladophlebis and Pecopteris denticulata
relationships has been contributed in recent studies due to ill preservation (Watson in Bull. Brit. Mus. Nat. Hist. Geol. 17: 237. 1969; Van Amerom & al. in Meded. Rijks. Geol. Dienst, Ser. 2, 27: 47. 1976). In addition, the name applies to the only species from the atypical Cretaceous, not Jurassic strata, from which have been described almost all Cladophlebis species, and we have no guarantee that this Cretaceous species, when found in a fertile state, might not be generically distinct from a bulk of Jurassic taxa. Its fragmentary preservation and the lack of any idea of its fertile state forced me to refrain from its acceptance for the type of the generic name, although some researchers follow this inadmissible, later typification (Boureau & Doubinger in Boureau, Traité Paléobot. 4(2): 203. 1975; Durante in Trudy Sovm. Sov.-Mongol. Geol. Exped. 19: 133. 1976; Cantrill in Antarct. Sci. 12: 187. 2000; Rees & Cleal in Spec. Pap. Palaeontol. 72: 25. 2004). Making use of this opportunity to conserve the type of Cladophlebis since that of the sectional name upon which it is based is referable to Palaeoweichselia and the next selection (that by Dawson, l.c.) has turned out to be inappropriate being referable to quite another genus Todites and the later lectotypification, often formally cited, is based on very ill-preserved remains with no confirmed relationships with a core of the genus and its modern understanding (Harris, l.c. 1961), it is appropriate to choose the name of a species the details of the structure of which and hence its relationships are better known and most closely correspond to the current use of this predominantly Jurassic genus. Among species of Cladophlebis listed by Brongniart in 1849, I noticed C. ligata and C. dentata, which are currently (but not correctly!) treated as synonyms of the very widespread Jurassic marker species, C. denticulata (Brongn.) Schimp. (Traité Paléontol. Vég. 3: 660. 1874 non Fontaine 1889 (see Addendum below). The fertile state of this famous species is well known and classified, depending on the author, as Todites undans (Lindl. & Hutton) Harris (in Meddel. Grønland 112(2): 14. 1937) or Cladotheca undans (Lindl. & Hutton) Halle (in Ark. Bot. 10(15): 4. 1911). Although not originally listed by Brongniart (l.c. 1849) in the protologue of Cladophlebis, the species is widely used in Jurassic palaeobotany being a biostratigraphic marker in addition in different areas of the World (see Jongmans & Dijkstra in Jongmans, Foss. Cat. Pl. 36: 660–677. 1959), and strictly conforms to the modern circumscription and understanding of the genus Cladophlebis (Harris, l.c. 1961; Bodor & Barbacka, l.c.). However, this widespread species epithet is problematical. The species was described from the specimens sent to Brongniart by Williamson and Bean from Scarborough; analogous specimens were collected in the same horizon and geographical place and earlier illustrated and briefly characterized by Phillips (l.c.). One of them, Pecopteris ligata Phillips (l.c.: 148, t. 8, fig. 14. 1829), was validly published being accompanied by illustrations with analysis showing critical details of structure (Art. 38.7). We do not know the reasons that led Brongniart to mention it in the synonymy of his newly proposed species Pecopteris denticulata Brongn. (l.c. 1834), perhaps he might be treating it as nomen nudum due to lack of distinct diagnosis (but permissible up to 1 January 1908, Art. 38.7); but, at least, this species epithet has been supplied with description and additional illustration as Neuropteris ligata (Phillips) Lindl. & Hutton (Foss. Fl. Gr. Brit. 1: 197, t. 69. Jan 1833), again cited by Brongniart in synonymy. Nathorst (in Öfvers. Svenska Vetensk.-Akad. Förh. 5: 60, 79. 1880) suggested that Pecopteris ligata Phillips might be a badly preserved form of Laccopteris polypodioides, but neither Seward (l.c.: 81) nor Harris (l.c.: 102. 1961: ‘figure looks different’) accepted this re-interpretation of the fossil, both listed it definitely in the synonymy of C. denticulata. Thus, Pecopteris denticulata Brongn. is an illegitimate, nomenclaturally 1344
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superfluous species name (Art. 52.1) that ought to be replaced by its earlier validly published synonym, Pecopteris ligata Phillips, which has been nearly completely forgotten since the 19th century (cf. full synonymy in Seward, l.c.: 134). This nomenclatural mistake was not ever mentioned in the studies of Jurassic plants up to present nomenclatural analysis, and its direct correction might lead to the disappearance of one of the widest-known species epithets in palaeobotany and associated geological disciplines. We must adhere to the modern policy of not disrupting species nomenclature in current wide use by purely nomenclatural actions (Art. 56), and in this connection the species name C. denticulata, being proposed as conserved type for Cladophlebis, is formally proposed simultaneously to be conserved against its earlier synonym, Pecopteris ligata. No type has hitherto been designated for Cladophlebis denticulata and accordingly I designate here as lectotype the specimen cited in the heading (Great Britain, Yorkshire, Scarborough; Jurassic (Lower Bajocian)), which was solely illustrated by Brongniart (Hist. Vég. Foss. 1: t. 98, fig. 1a, 1b, 1834) and known to succeeding researchers; the other specimen from Brongniart’s protologue that survived (Mus. Natl. d’Hist. Nat. Paris: MNHN.F.610) was never illustrated or studied since the times of Brongniart, and hence it is left aside. The precise date of publication in addition to those listed in Taxonomic Literature II has been established for Phillips, Illustrations of the Geology of Yorkshire from the date of donation to the Library of the Yorkshire Philosophical Society in April, 1829 (vide Ann. Rept. Yorkshire Philos. Soc. 1829: 34. 1830); announced ‘to be published by subscription on Feb. 1, 1829’ (Philos. Mag. 5: 74: 1829), but no supportive records were found in contemporary British press. The precise date of publication has been found also for the treatment of fossil plants by Brongniart that appeared in d’Orbigny’s Dictionnaire universel d’histoire naturelle from the date of national bibliographical registration in the weekly Bibliographie de la France 38: 329. 7 Jul 1849 (week for 30 Jun–7 Jul). Brongniart’s treatment of fossil plants from the dictionary, published with its own pagination as Tableau des genres de végétaux fossiles, was reprinted later as confirmed by its bibliographic registration in the weekly Bibliographie de la France 38: 462. 15 Sep 1849 (week for 8–15 Sep), and hence the citation of Brongniart’s taxonomic novelties is correctly from the earlier published Dictionnaire. Addendum The name Cladophlebis denticulata was published independently from Brongniart by Fontaine in 1889 based on sterile fossil foliage from the younger Patuxent Formation (Lower Cretaceous [Aptian]) of North America and is therefore an illegitimate later homonym which should not be confused with species discussed above. As the name was not a misidentification of Brongniart’s species, but a distinct species (see detailed discussion by Jongmans & Dijkstra in Jongmans, Foss. Cat. Pl. 36: 661. 1959) I accordingly propose the replacement name Cladophlebis potomacensis Doweld, nom. nov. ≡ Cladophlebis denticulata Fontaine in Monogr. U. S. Geol. Surv. 15: 71, t. 4, fig. 2, (non t. 7, fig. 7) 1889 non (Brongn.) Schimp. 1874, with a new lectotypification of the species following arguments of Jongmans & Dijkstra (l.c.): lectotypus (hic designatus) [specimen] P3818, t. 4, fig. 2 (Paleobiology Dept., Natl. Mus. Nat. Hist., Smithsonian Inst.); the second specimen [P3286, t. 7, fig. 7], figured and included by Fontaine (l.c.) under his C. denticulata, is best left aside due to its fragmentary preservation. The practice of some modern authors (e.g., Rees & Cleal, l.c.: 26. 2004; Barbacka & Bodor in Acta Palaeobot. 48: 135. 2008; Diéguez & al. in J. Iber. Geol. 35: 131. 2009) to erroneously mix the two unrelated fossil species under
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Doweld • (2246–2247) Conserve Todites and Pecopteris williamsonis
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the single epithet denticulata should be stopped; C. potomacensis is a distinct North American species entity related rather to Cretaceous cladophleboid species C. albertsii (Dunker) Brongn. Acknowledgements Thanks go to the British Library Rare Books Division and Corporate Archive (C. Algar, Q. Wright, M. Woods) for courtesy and
assistance in determining dates of publication of British palaeobotanical books and special thanks to Valentina Bublik (Fundamental Botanical Library of the National Institute of Carpology, Moscow) for bibliographic searches. The research is a contribution to Palaeoflora Europaea Project and Palaeoflora of Russia (Palaeoflora Rossica) Project (NOM-10-1017).
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