ON A NEW GENUS OF LATE PALEOZOIC PLANTS

BOROVUCHKIA PARFENOVA GEN. NOV.

FROM THE KEMEROVO REGION OF KUZBASS

M. D. PARFENOVA

(Presented by Prof. Dr. G. G. Khakhlov)

In a large collection of Late Paleozoic plants from the Kemerovo region of Kuzbass, we encountered impressions of leaves distinctive in their morphology and in the anatomical structure of the epidermis. Upon detailed study of these impressions, we considered it possible to distinguish them as an independent genus and species under the name Borovuchkia kemeroviana Parfenova sp. nov.

The name of the genus and species is given in connection with the locality of these impressions in the Kemerovo region, at the Borovushinsky exploration site. We give a description of this plant.

Genus Borovuchkia gen. nov.

Type species: Borovuchkia kemeroviana sp. nov., from the Intermediate Subsuite of Kuzbass.

A pinnate or bifurcate frond with an oblong, rather fleshy rachis. The pinnules are lingulate or elongate-lingulate, attached to the rachis by means of a short petiole. The veins are coarse, broad, and flat. There is a median vein, which seems to continue the petiole and immediately gives off coarse lateral branches, repeatedly dichotomizing and deflecting to one degree or another toward the sides. Somewhat above the base of the pinnules, the lateral veins diverge more weakly, are directed almost parallel to the median vein, and mask the latter—it seems to merge with them.

This plant is of interest because in its individual characters it resembles representatives of a number of genera, namely: Cardiopteridium Nathorst, Angaropteridium Zal., Cardiopteris Schimper, Neuropteridium Schimper, and Cardioneura Zal.; at the same time, however, it cannot be assigned to any one of these genera. It differs from all the genera listed by the combination of such characters as the lingulate form of the pinnules, the attachment of the pinnules by means of a petiole, and their coarse venation with the presence of a median vein. None of the genera listed above possesses all these characters taken together. It may be assumed that our genus testifies to the closeness of all these genera, uniting the characters inherent in the mentioned genera individually.

Distribution. The very lowest beds of the Intermediate Subsuite of the Balakhonka Series of Kuzbass.

Table I

Borovuchkia kemeroviana sp. nov.

Kemerovo deposit, Borovushinsky site

Fig. 1–8. Holotype. Specimen 523. Borehole 2675, depth 211.55 m, interbed of the Dvoynoy-Promezhutochny seam.

Fig. 1, 3, 5, 8 — anatomical structure of the epidermis, ×103; fig. 1, 3 — in the middle part of the segment between the veins; fig. 5 — along the margin of the segment; fig. 8 — at the base of the segment. Fig. 2 — surface of an individual segment; enlarged.

Fig. 4 — attachment and venation of the segments, ×4.

Fig. 9. Specimen 732, borehole 3036, depth 328.20 m, 60 m above the Dvoynoy-Promezhutochny seam.

Borovuchkina kemeroviana sp. nov.

Plate 1, figs. 1–9; text-fig. 1

Holotype. Collection of the Tomsk Polytechnic Institute, specimen No. 523. Kuzbass, Kemerovo District, Borovushinskii area, borehole 2675, depth 211.55 m. Balakhonka Series, Dvoinoi-Promezhutochnyi seam.

Morphology. The frond is simply pinnate or forked, possibly lancet-shaped. The frond axis is thick, with coarse longitudinal wrinkles. The pinnules are arranged alternately, closely spaced, and at the apex of the frond—oppositely. The pinnules are attached to the rachis by means of a short petiole, which departs from the rachis almost at a right angle. On the rachis of young branches, at the points where the pinnules are attached, there are nodes, producing the impression that the rachis is articulated. The pinnules are tongue-shaped, elongate, with a blunt, almost spatulate apex and a cordate base; they are attached to the rachis at an angle of 70–90°. Young pinnules narrow slightly toward the apex. Older pinnules have parallel lateral margins and a broadly rounded apex. The auricles at the base of the pinnule are almost equal in young pinnules, but the lower auricle is somewhat more developed in old pinnules. The pinnules touch one another with their margins, and at the apex of the frond they slightly overlap one another.

One broad, strong vein enters the base of the leaf in the form of an axis, constituting the continuation of the short petiole on which the leaf is attached. This midvein immediately gives off, on both sides, several strong, coarse branches, which diverge strongly to the sides, dichotomize up to four times, and reach the margin at the base of the pinnule. Higher up, the lateral branches from the midvein diverge increasingly less to the side, are directed almost upward, and thus mask the midvein.

The secondary branches of the lateral veins, bending arcuately to the side, dichotomize 3–4 times and reach the margin; the veins dichotomize for the last time 1–1.5 mm from the margin. On the surface of the veins, especially on old pinnules, transverse striation is observed, which is more sharply visible on the larger and older veins. All veins are broad, flat, and coarse. On young leaves the venation is dense; along the margin of the pinnule there are up to 20 veins per 0.5 cm. Young pinnules have pronounced wrinkling in the direction of the veins. The entire surface of the pinnule between the veins is covered with distinct, linear grooves running parallel to the veins.

Dimensions: length of frond fragments 25–60 mm. Width of the rachis 2–5.5 mm. Length of pinnules 11–43 mm, width of pinnules 6–15 mm.

Structure of the epidermis. The cells are polygonal, rounded-polygonal, elongated, closely adjoining one another, and oriented.

Between the veins, near the base of the leaf, the cells are rounded, rounded-polygonal, unoriented, 34.9–46.4 μ in size. The cells along the veins are elongated, polygonal, with pointed ends or quadrangular, oriented along the veins; owing to the strips of cells on the veins, a general orientation of the leaf cells is produced. The strips of cells on the veins consist of 3–6 rows of cells. The dimensions of the cells on the veins are 17.5–23.3 × 81.5–116.5 μ. Somewhere in the middle of the leaf the cells are elongated in the direction of the veins and consequently also along the length of the leaf, slightly loop-shaped, predominantly narrow. Their dimensions are the same as those of the cells on the veins. At the point of attachment of the leaf, i.e., where the veins emerge, the cells are predominantly elongated, but there are also rounded, polygonal—

... extend fanwise in the form of a bundle. The stomata are scattered throughout, without a definite order, in the spaces between the veins, slightly sunken into the leaf tissue. The shape of the stomata is oval, more rarely rounded, with a slit-like elongated aperture. The stomata consist of two semilunate cells. The stomatal apertures are directed perpendicular or oblique to the veins. The length of the stomata is 34.9 μ, the length of the stomatal aperture 23.3 μ. Along the margin of the leaf the cells are narrow and elongated, almost identical with the cells on the veins, while at the very margin they are arranged irregularly and bend parallel to the margin toward the apex. The dimensions of the cells at the leaf margin are 11.6–23.3 × 46.6–116.5 μ.

Comparisons. The most characteristic features of the species (apart from the anatomical structure of the epidermis) distinguishing it from all known species are: the form of the pinnules, their attachment to the rachis by means of a short petiole, the wrinkling and striping of the young pinnules, the transverse striation of the veins on old pinnules, and the general character of the venation.

Fig. 1. Borovuchkia kemeroviana sp. nov. Reconstruction of the leaf epidermis (schematized and enlarged).

Material. We have three specimens of this species. On two of them (impression and counter-impression) three fragments of a frond are preserved: one represents the apical part of a frond with six pairs of pinnules; the other two are small fragments near the apical part of the frond with two or three pairs of pinnules. The arrangement of all the listed fragments on the impression gives some grounds for supposing that the frond had a forked character. The third specimen bears the impression of a fragment of a frond with three pairs of large pinnules, probably from a more developed part of the frond. Higher along the margin of the specimen, fragments of three more pairs of overlying pinnules and a fragment of a pinnule belonging to another pinna or frond are visible.

Distribution. Borovushinskii area, borehole 2675, depth 211.55 m, Dvoinoi-Promezhutochnyi seam; borehole 3036, depth 328.20 m, 60 m below the Dvoinoi-Promezhutochnyi seam.

REFERENCES

1. Neiburg M. F. Upper Paleozoic flora of the Kuznetsk Basin. Paleontology of the USSR, vol. XII, part 3, issue 2, 1948.

2. Novik E. O. The Carboniferous flora of the European part of the USSR. Paleontology of the USSR, new ser., vol. 1. Publishing House of the Academy of Sciences of the USSR, 1952.

3. Sukhov S. V. Materials for the study of the Paleozoic flora of the Kenderlyk and Zaisan depressions (Eastern Kazakhstan). Transactions of VNIGRI, issue 124, 1958.

4. Radchenko M. I. On the genus Cardiopteris Schimper from the Lower Carboniferous deposits of Eastern Kazakhstan. Transactions of the Institute of Geological Sciences, Academy of Sciences of the USSR, vol. 3, 1960.

5. Parfenova M. D. On the anatomical structure of Upper Paleozoic plants of Kuzbass. Reports of the Paleobotanical Conference. Publishing House of Tomsk State University, 1962.