(2189) Proposal to conserve the name Pityostrobus against Zamiostrobus (fossil Gymnospermae , Pinopsida )

The genus Pityostrobus was established by Dutt (l.c.) for petrified ovulate cones from the Eocene sediments of Great Britain, now known also from the Upper Jurassic to the Early Cretaceous–Miocene, being widely distributed in Europe, Siberia, Central and Eastern Asia, India, North and South America, and comprising at present ca. 30 species (Miller in Beck, Orig. Evol. Gymnosp.: 471. 1988; Shang & al. in Bot. J. Linn. Soc. 136: 427. 2001; Smith & Stockey in Int. J. Pl. Sci. 162: 669. 2001). The genus is one of the commonest and most widely accepted in modern palaeobotany (Alvin in Mem. Inst. Roy. Sci. Nat. Belgique 125: 5. 1953, 135: 1. 1957, 146: 10. 1960; Creber in J. Linn. Soc., Bot. 56: 421. 1956; Turutanova-Ketova in Orlov, Osnovy Paleontol. [15]: 278. 1963; Miller in J. Paleontol. 50: 821. 1976, in Bull. Torrey Bot. Club 104: 5. 1977, in Bot. Gaz. (Crawfordsville) 139: 284. 1978; Smith & Stockey, l.c., 163: 185. 2002; Germandt & al. in Int. J. Pl. Sci. 169: 1086. 2008), although it is ill-defined and probably needs to be revised and dismembered into a few, more natural. generic segregates. When establishing the new generic name on the basis of “Nathorst’s name Pityostrobus”, a designation applied by Nathorst (in Kongl. Svenska Vetensk. Acad. Handl., ser. 2, 30(1): 62. 1897) without description to one of his provisional morphotaxon subdivisions of Pinites, Dutt (l.c.) appears to have overlooked the fact that he definitely included in Pityostrobus the type of the earlier validly published generic name Zamiostrobus, Z. macrocephalus, and, therefore, according to Art. 52.1 & 52.2, his new generic name was a superfluous, illegitimate synonym of Zamiostrobus. Dutt definitely synonymized two distinct species, Pinites macrocephalus (Lindl. & Hutton) Carruth. and Pinites ovatus Carruth. under the single species Pityostrobus macrocephalus (Lindl. & Hutton) C.P. Dutt. Perhaps, this nomenclatural error might have proceeded from the incorrect generic diagnosis of Zamiostrobus. Endlicher (l.c.) created this new genus to accommodate a distinct species, Zamia macrocephala Lindl. & Hutton (Foss. Fl. Gr. Brit. 2: 117. 1834), possessing a single ovule on each megasporophyll; Goppert (in Ubers. Arbeiten Verand. Schles. Ges. Vaterl. Cult. 1843: 128. 1844) was the first to formally combine Zamia macrocephala into Zamiostrobus [exact date of publication of Goppert’s work (l.c.) has been established via the known date of its sending by Goppert to the Prussian Academy of Sciences in Berlin (vide Ber. Bekanntm. Verh. Konigl. Preuss. Akad. Wiss. Berlin 1844: 292. 1845)]. However, Corda (in Reuss, Verstein. Bohm. Kreideform. 2: 84. 1846) and later, more convincingly, Carruthers (in Geol. Mag. 3: 534–546. 1866), both re-interpreted the structure of the cone as having two ovules per megasporophyll and in general comparable to pinaceous cones, and it was in this sense that the new generic name Pityostrobus appeared with an updated and corrected diagnosis and soon widely entered into palaeobotanical systematics. Since 1836, the genus Zamiostrobus has occasionally been adopted for true cycad-like cones (Unger, Gen. Sp. Pl Foss.: 298. 1850; Miquel, Prodr. Syst. Cycad.: 29. 1861), that were later re-classified into several distinct genera, Cycadeostrobus Carruth., Microzamia Corda, etc. At the time of Dutt, Zamiostrobus was an ill-defined, highly broadened genus, included both cycad-like and coniferous cones (belonging to its type). Dutt’s nomenclatural mistake has never been corrected, and the prevalence of use of Pityostrobus in old and modern palaeobotanical literature, along with nearly complete disappearance of the generic name Zamiostrobus from modern palaeobotanical literature, makes it important to retain use of Pityostrobus. After final summary of the generic status and species circumscription of Zamiostrobus (Schuster in Bot. Jahrb. Syst. 64: 178. 1931 & in Engler, Pflanzenreich IV.1 (Heft 99): 58. 1932; Jongmans & Dijkstra in Dijkstra, Foss. Cat. Pl. 65: 3640. 1967), the name has ceased to be used except for occasional, opportunistic use through its likeness to cycad-like cones, which is merely a mistake (Bock in Geol. Center Res. Ser. 3–4: 218. 1969), or just an occasional lapsus (Taylor & al., Paleobotany: 719. 2009). Accordingly it is suggested to preserve current palaeobotanical nomenclature by conservation of Pityostrobus C.P. Dutt against its earlier taxonomic synonym, Zamiostrobus Endl.