USNM 37333 Nilssonia yukonensis Hollick  


Hollick (1930)

Pl. 3 Fig. 2




From Hollick (1930) (p. 42)

"Yukon River, north bank, about 6 miles above Nahochatilton (original No. 3AH16); collected by Arthur Hollick and Sidney Paige in 1903 (lot 3252) (pl. 3, figs. 1-3; pl. 7, fig. 4). Yukon River, north bank, about 12 miles below Melozi telegraph station (original No. 3AH11); collected by Arthur Hollick and Sidney Paige in 1903 (lot 3248) (pl. 3, figs. 4,6,7a).


Locality Map



From Hollick (1930) (p. 42)

"Plate 3, Figures 1- 7a; Plate 7, Figure 4"

"Leaves of various sizes, approximately 5 to 8 centimeters in length, linear oblong or spatulate, narrowed below to a cuneate base, terminating more or less abruptly above in a truncate or broadly emarginate apex; margin entire; nervation fine, simple, parallel throughout and curved gently upward."



From Hollick (1930) (p. 42)

"This species belongs with the general type of leaf represented by Nilssonia orientalis Heer (1878) (p. 18, pl. 4, figs. 5 - 9) of supposed Jurassic age, from the Lena River region of Siberia, and Nilssonia johnstrupi Heer (1882) (p. 44, pl. 6, figs. 1 - 3, 4a, 4b, 4c, 5a, 6) of early Upper Cretaceous age, from the Atane beds of Greenland. N. orientalis is recorded by Fontaine (1905) (p. 90, pl.16, figs. 3 - 9) from the Jurassic of Oregon, and N. johnstrupi is recorded from the Cretaceous of Washington and described and figured by Newberry (1865; 1898) (p. 512; p. 16, pl. 15, figs. 2, 2a) first in 1863, under the name Taeniopteris gibbsii, and subsequently, in 1898, as Nilssonia gibbsii.

The conspicuous apical sinus in our specimens, however, aside from any other characters, serves to differentiate them from either of the above-named species. This conspicuous character is suggestively foreshadowed however, in one of Heer's Siberian specimens (1878) (pl. 4, fig. 5) and also in certain of the Oregon specimens figured by Fontaine (1905) (p. 16, figs. 7, 13) and referred to Nilssonia orientalis Heer and N. orientalis minor Fontaine. Another species, similar to the latter but apparently much more elongated, is Nilssonia bohemica Velenovsky (1885) (p. 11, pl. 2, figs. 25 - 28) from the Cretaceous of Bohemia, and it is evident that this general type of Nilssonia was one which had a wide geographic and considerable vertical range.

The apparently abnormal specimen represented by our Plate 3, Figure 1, might be regarded as a distinct species; but it differs from the typical form of the species no more than the various forms of Nilssonia orientalis differ among themselves; and it is interesting to note that the peculiar constricted summit in this specimen is also indicated in certain figures of each of the other species mentioned.

Incidentally it may also be of interest to call attention to the leaf figured under the name Phyllites scitaminaeformis Sternberg (1823) (pp. 37, 39, pl. 37, fig. 2 [= Taeniopteris scitaminea Presl, idem, vol. 2, pts. 7 and 8, p. 139, Prag, 1838) from the Jurassic of England, and to compare it with the retuse and emarginate types of Nilssonia leaves."