Locality
Sagwon 05-3. Prince Creek Formatlon. Sagavanirktok River. Sagwon.
Description
(a) Archeampelos mullii Moiseeva et Herman
The following is not a description of this particular specimen but a composite description of the species.
From Moiseeva, Herman, Spicer. 2009. (p. 1304-1306)
"Diagnosis. Leaves simple, entire, medium-sized, length/width ratio about 1 : 1. Leaf lamina rounded and symmetric. Leaf base truncate or broadly rounded. Leaf apex obtuse or mucronate. Leaf margin irregularly undulate-crenate, entire at leaf base. Teeth rounded asymmetric, of variable prominence and spacing. Venation pinnate-palmate and craspedodromous. Midrib sinuous. Secondary veins three or four pairs, of which two basal pairs nearly as strong as midrib, ascending to upper third of leaf lamina, forking and ending in marginal teeth.
Description (Figs. 2e, 2f). The only specimen (part and counterpart) is moderate in size, about 6–7 cm long and 7–8 cm wide. The leaf is simple, entire, symmetrical, and rounded. The maximal width occurs in the middle of the leaf lamina. The length/width ratio is about 1 : 1. The leaf base is truncated or broadly rounded. The apex is broadly rounded or shortly acuminate. The leaf margin is basally entire and irregularly undulate-dentate in other regions. The teeth are low, rounded, variable in size, up to 3 mm long and 6 mm wide, asymmetrical. The notches between the teeth are usually rounded or, occasionally, acute.
The venation is palmate-pinnate and craspedodromous. The midrib is sinuous. Three or four pairs of secondary veins are alternating from the midrib at an angle of about 40°. Each secondary vein also produces several branchlets. Two lower pairs of secondary veins are nearly as thick as the midrib. They depart from the leaf base, fork in the middle area of the leaf lamina, and end in marginal teeth. The tertiary venation is relatively loose, branched-scalariform, and orthogonal-reticulate in places. The tertiary veins are sinuous and loop near the margin.
Comparison. The new species resembles by the leaf lamina outline, its base, and primary and secondary venation the type species of Archeampelos, A. acerifolia from the Ravenscrag Formation (Paleocene) in western Canada (McIver and Basinger, 1993). The new species differs by having an irregularly undulate-crenate margin, sinuous forking veins of the first order, and rare and less regular tertiary venation."
Remarks
This species was named in honour of C.G. (Gil) Mull.
From Moiseeva, Herman, Spicer. 2009. (p. 1304-1306)
"Genus Archeampelos McIver et Basinger, 1993 Archeampelos mullii Moiseeva et Herman, sp. nov. Plate 23, figs. 1, 2.
Holotype. GIN, no. 4886/24c (part) and 4886/24a-3 (counterpart); leaf imprint, Sagavanirktok River, northern Alaska; upper part of the Prince Creek Formation, Upper Paleocene; Pl. 23, fig. 2, Fig. 2f (part) and Pl. 23, fig. 1, Fig. 2e (counterpart)."
"Similar leaves were described from the Paleocene of western Canada as Acer arcticum Heer (Bell, 1949). Archeampelos mullii differs from this species by a sinuous midrib and the leaf margin, which has a less distinct teeth in places transforming into an undulate margin.
Morphologically similar leaves from the Late Maastrichtian Koryak Flora of the Amaam Lagoon in north-eastern Russia were assigned to Cissites Heer (Moiseeva, 2005b). Archeampelos mullii sp. nov. most resembles leaves of Cissites hermanii Moiseeva, which also has forking lateral primary veins. Unlike these leaves, the leaves of the new species are characterized by a rounded outlines, absence of lobes, smaller marginal teeth, and rarer tertiary venation."
Description
(b) Tiliaephyllum brooksense Moiseeva et Herman
The following is not a description of this particular specimen but a composite description of the species.
From Moiseeva, Herman, Spicer. 2009. (p. 1303-1304)
"Leaves simple, entire, medium-sized to large. Leaf lamina elliptic-ovate or broadly ovate. Leaf base asymmetric, typically deeply cordate or, more rarely, emarginate. Leaf apex acuminate to attenuate. Leaf margin unequally toothed or double-serrate. Teeth from small to large, acute, triangular, symmetric, or, more rarely, narrow asymmetric and oriented apically. Venation pinnate and craspedodromous. Secondary veins 10–13 pairs, opposite or, more rarely, alternate. The third basal pair of secondary veins the strongest and copiously branched.
Description (Figs. 2a–2c). The leaves are medium-sized or large, 5–12 cm long and 3.5–10 cm wide, simple, entire-margined, oval-ovate or broadly ovate, the maximum width is located in the middle of the leaf or below the middle. The leaf base is asymmetrical, deeply cordate or, more rarely, emarginate; the apex is acute and, as a rule, acuminate. The petiole is relatively thick, its length is about one third of the leaf lamina length. The leaf margin is unequally toothed or double-serrate. The teeth are from small to large (up to 2.5 mm high and 3–4 mm wide). Usually, they are acute, triangular, with straight or slightly concave sides, symmetrical, or, more rarely, narrower, with a concave apical side, and orientated towards the leaf apex. The notches between the teeth are mostly acute or, more rarely, rounded.
The venation is pinnate and craspedodromous. The midrib is thick, straight, or slightly sinuous. There are ten to thirteen pairs of secondary veins. Most secondary veins are opposite, some are alternating. Three lower pairs of veins are connivent with their bases. The longest and most branched pair of veins is the third (from the bottom) pair: up to six basiscopic branchlets depart from this pair of veins. Below this pair, the first two pairs of secondary veins are situated; they are also quite frequently branched (with four or five branchlets), but much shorter. They depart from the midrib at a right angle; the lowest are slightly curved downwards, the angle of deviation of other secondary veins is 40–50°. The tertiary venation is scalariform or, more rarely, branched-scalariform.
Comparison. The new species differs from Tiliaephyllum tsagajanicum from the Upper Tsagayan Flora of the Amur Region (Krassilov, 1976) by the pattern of secondary venation in the lower part of the leaf. The third (from the bottom) pair of secondary veins is longest and most branched in T. brooksense sp. nov. Unlike this species, T. tsagajanicum has the longest lower pair of secondary veins departing immediately from the leaf base."
From Moiseeva, Herman, Spicer. 2009. (p. 1303-1304)
"Genus Tiliaephyllum Newberry, 1895. Tiliaephyllum brooksense Moiseeva et Herman, sp. nov. Plate 22, figs. 1–7.
Holotype. GIN, no. 4886/21a-1, 4886/21b-1 (counterpart); leaf imprint; Sagavanirktok River, northern Alaska Peninsula; upper part of the Prince Creek Formation; Upper Paleocene (Pl. 22, fig. 2; Fig. 2a)."
"The morphologically close species Tiliaephyllum tsagajanicum was first described by Kryshtofovich and Baikovskaya (1966) from the Tsagayan Flora of the Amur Region as Tilia L. The holotype of this species is shown in Fig. 3 (no photograph was published by Kryshtofovich and Baikovskaya). This specimen has smaller and more steeply apically oriented teeth than the majority of other specimens of T. tsagajanicum, that, in our opinion, accords with intraspecific variability.
The new species has something in common with leaves of Corylites L., which were wide-spread in many temperate floras of Asia, Europe, and North America (Boulter and Kvacek, 1989; Manchester and Guo, 1996; Akhmetiev and Golovneva, 1998; Moiseeva, 2005a; and others). Tiliaephyllum brooksense sp. nov. differs from most species of Corylites by wider and more rounded outlines of the leaf lamina and larger and usually symmetrical marginal triangular teeth. In addition, the new species is characterized by highly branched third (from the bottom) pair of secondary veins, whereas most species of Corylites usually have the lower or the second (from the bottom) pair of secondary veins most strongly developed. One of the distinguishing features of Tiliaephyllum is an acuminate leaf apex, which occurs much more rarely in Corylites."