05RAS Archeampelos mullii Moiseeva et Herman  


Moiseeva et al. (2009)



Sagwon 05-3. Prince Creek Formatlon. Sagavanirktok River. Sagwon.

Locality Map



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."



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."