Mciveraephyllum nebrascense (SCHIMPER) Manchester, 2014

Manchester, Steven R., 2014, Revisions To Roland Brown’S North American Paleocene Flora, Acta Musei Nationalis Pragae Series B 70 (3 - 4), pp. 153-210 : 178-179

Mciveraephyllum nebrascense (SCHIMPER) comb. nov.

Text-fig. 11

1868 Cornus acuminata NEWBERRY, Lyceum Nat. Hist. New York Ann., 9, p. 71. [non Webber 1852].

1874 Cornus nebrascensis SCHIMPER, Traité de paléontologie végétale 3, p. 54 [basionym].

1898 Cornus newberryi HOLLICK in NEWBERRY, p. 124, pl. 37, figs 2–4.

1962 Ficus artocarpoides Lesquereux auct non. Brown [part], pl. 28, fig. 1–3, 5–7, not 4.

1993 Cornophyllum newberryi (HOLLICK) MCIVER et BASINGER p. 45, pl. 35, figs 2–5, Pl. 36, figs 1–3.

L e c t o t y p e (designated here): USNM 8937 ( Text-fig.

11.1; pl. 37, fig. 4 of Newberry 1898).

E m e n d e d D i a g n o s i s provided by McIver and

Basinger (1993, “ Cornophyllum newberryi ”

As summarized by Peppe (2009), the diagnostic features of this species are the highly ascending, evenly spaced, eucamptodromous secondary veins that turn sharply up near the margin and become increasingly decurrent in their attachment to the mid-vein towards the base, and the tendancy for prominent marginal teeth. This species was initially called Cornus acuminata NEWBERRY (1868) (subsequently renamed twice because the binomial was a junior homonym of Cornus acuminata WEBBER : Cornus nebracensis SCHIMPER 1874 and Cornus newberryi HOLLICK in NEWBERRY 1898) was founded on three syntypes from “Yellowstone River, Montana ” [probably in the vicinity of present-day Miles City] ranging from entire-margined to, in the case of the lectotype, having prominent teeth in the upper half of the lamina (text-fig. 11; Brown 1962, Manchester et al. 2009).

Although extant Cornus can have a minutely erose margin ( Hickey 1977), no species of this genus have prominent teeth, so the original assignment of this species to Cornus is not supported. One of the diagnostic features of Cornus leaves is the presence of abundant calcified double-armed acicular trichomes. This feature also does not occur in Newberry’s species, although the trichomes are preseved and visible as impressions under high magnification in many genuine Cornus leaves from various sites of the Fort Union Formation ( Cornus swingii MANCHESTER, XIANG, KODRUL et AKHMETIEV 2009). The lectotype, and other architecturally similar specimens, do not show any such trichomes. Although it is clear that Newberry’s species does not belong to Cornus , the true systematic affinities remain uncertain. I therefore propose a new genus, Mciveraephyllum , accommodating Mciveraephyllum nebrascense (SCHIMPER) comb. nov. McIver and Basinger (1993) also concluded that this species cannot be Cornus , and reassigned it to the genus Cornophyllum NEWBERRY. However , Cornophyllum was diagnosed on the basis of entire-margined leaves from the Cretaceous Raritan of New Jersey ( Newberry 1895), and therefore is not appropriate for this leaf type which commonly is toothed. Because the original binomial, Cornus acuminata , was illegitimate, the epithet with priority is nebrascensis , as explained by Peppe (2009).

Most of the leaves placed by Brown (1962) in Ficus artocarpoides LESQUEREUX belong to Mciveraephyllum nebrascensis [except for one of the figured specimens ( Brown 1962, pl. 24, fig. 4) that subsequently transferred to Leepierceia preartocarpoides (R. W. BROWN) K. JOHNSON ( Johnson 1996)]. M. nebrascensis leaves vary from entire margined to dentate, with sharp, widely spaced teeth and rounded sinuses and have moderately long petioles. Leepierceia has laminae with similar teeth, but the base is usually cordate, and the tertiaries and higher order veins are much more prominent ( Johnson 1996).

Figures

Text-fig. 11. Indet. family. Mciveraephyllum nebrascense (SCHIMPER) comb. nov. 1. Lectotype of Cornus acuminata NEWBERRY 1868 [non Webber 1852] = Cornus nebrascensis SCHIMPER 1874, p. 54, originally pl. 37, fig. 4 in Newberry 1898. Yellowstone River, Montana, USNM 8937. 2. Specimen from Black Buttes pit 3, Wyoming showing moderately long petiole and rounded tooth sinus. UF 15886-14308. 3. Specimen with more abundant teeth, Ludlow Formation, locality DMNH 563, Slope County, North Dakota, Collection of K. Johnson, DMNH 2206. 4. Detail of tertiary venation, counterpart specimen of that figured in 2. Scale bar = 2 cm.