Todites lobulatus, V.Naugolnykh, 2002

V. Naugolnykh, Serge, 2002, A new species of Todites (Pteridophyta) with in situ spores from the Upper Permian of Pechora Cis-Urals (Russia), Acta Palaeontologica Polonica 47 (3), pp. 469-478 : 470-473

Todites lobulatus sp. nov.

Figs. 3–7 .

Holotype: GIN 4846/102 .

Type horizon: Bed 103 , Intinskian Formation , Upper Permian (Ufimian).

Type locality: Left bank of Kozhim River , 4 km downstream from the bridge near Kozhim−Rudnik station, the Pechora Cis−Urals , Russia.

Derivation of the name: From Latin lobulatus , lobed.

Diagnosis.—Ferns with tripinnate fronds. Pinnules deeply dissected with well developed lobes.Pinnule apex round. Sporangia free, located on abaxial leaf surface.Sporangia round or ovoid, small (0.5 mm in diameter), with group of thick−walled cells on sporangia top or side.Spores circular, laesura trilete, radii simple, straight, spore surface sculptured by granulate scabrae.Size of the spores ranges from 20 to 45 µm.

Material.—Two representative pinnae of last order belonging to one individual plant.

Description.—The single representative fragment of a tripinnate frond with two preserved pinnae of the last order is shown on Fig.3A–D and Fig.4 .The preserved part of the most complete pinna is 31.5 mm long and 2.8 mm wide. The pinna rachis is straight in the apical part, but slightly curved (undulating) in its proximal part.The rachis width is 1.5 mm.

The narrow wing is present in the apical part of the pinna. One can see eight pinnules with lobed margins.The pinnules are attached to the pinna rachis in regularly alternate order. Pinnule length varies from 13.3 up to 15.8 mm. Maximal width of the pinnules is 8 mm.Pinnule outlines are sub − triangular.

The frond surface is exposed on its adaxial side without sporangia.Since the leaf lamina is considerably eroded, the numerous sporangia attached to abaxial frond surface are clearly seen ( Fig. 3B, C ).

The pinnules are dissected into well developed lobes in 1/2 of pinnule width in their proximal parts.The apical parts of the pinnules are not so deeply dissected.The pinnate vena − tion is simple.One well developed robust midvein enters each pinnule.Lateral veins enter each pinnule lobe.Lateral veins in the apical part of the pinnule are simple; those of the proximal parts of the pinnules are rarely pinnately branched. Lateral veins originate from the midvein in alternating order, but sometimes almost opposite.The pinnule apex is round, the pinnule base is narrow, sphenopteroid.

The abaxial surface of the leaf lamina is covered by sporangia and one pinnule bears up to three hundred sporangia.Sporangia are so closely spaced, that they appear to form a mass, in which single sporangia are very difficult to observe.Individual sporangia are small (about 0.5 mm in di − ameter), round or ovoid, and bear small stalks basally (sporangiophore), by which they are attached to the leaf lamina.

One can see several well preserved sporangia, each showing a group of specialized cells with thicker walls located near the sporangial stomium ( Figs.3C , 5), which represents the opening mechanism of maturity.This structure is charac − teristic of recent osmundalean ferns, and fossil ones.

The uppermost fertile pinnule figured in Fig.3A and Fig.4 , right, was macerated.Numerous spores were extracted from the sporangia.During the maceration the sporangium walls were completely dissolved, but all spores were preserved in situ as a round or spherical mass ( Figs.6F, G , 7A–F ).This mass of spores has outlines corresponding to the original form of the sporangium.Separate spores are clearly seen at the periferal zone of the spore mass ( Fig.7B, C ).The spores have a well developed tetrad scar (trilete mark or laesura), and the rays of the trilete mark almost reach the spore margin ( Figs. 6E–G , 7D ).The spore surface is sculptured by very fine granu − late microstructure ( Figs.6D , 7B, D ).Very similar, but slightly more developed and larger, spores were extracted from the matrix housing the Todites lobulatus fertile pinnae ( Figs.8 , 9 ). Most probably they belonged to the same species, but dispersed spores have a larger size because they are mature as opposed to those still in the sporangia.The dispersed spores of the same type, which can be attributed to Osmundacidites Couper, 1953 , are known from the Upper Permian of other regions of the Urals and the Russian platform.

Comparison and remarks.—The new species differs from the type−species Todites williamsonii ( Brongniart, 1828) Seward, 1900 in having deeply dissected pinnules and round pinnule apices; from T. crenatus Barnard, 1965 in considerably shorter and wider pinnules; from T. sibiricus (Schmalhausen, 1879) Radczenko, 1955 and T. evenkensis Radczenko, 1955 in having well developed pinnule lobes, but shares with them the general structure of the fertile pinnules, e.g., form and position of sporangia; from T. sibiricus —in larger size of the pinnules (15 mm instead 8–10 mm) and slightly curved pinnule (straight pinnules of T. sibiricus are disposed almost perpendicularly to the pinna rachis), from T. evenkensis —in round pinnule apex and wider angle of pinnule orientation on the last order pinna; Todites lobulatus has narrow wings on the rachis.In contrast, T. sibiricus and T. evenkensis have no wings.

Fefilova (1973) described several sterile and fertile pinnae from the Upper Permian (Ufimian and Kazanian) deposits of Kosju, Big Synja and Perebor river basins (Pechora Cis−Urals).These pinnae were attributed to Todites sp. in open nomenclature.Some spores of Lophotriletes Potonie and Kremp, 1954 were extracted from the sporangia.Later very similar fertile fronds of Todites sp. were reported from the Seidinskian and Talbeiskian Formations (presumably Kazanian in age, at least partly) of the Pechora coal district, in the Heyaha and Adzva rivers basin (Pukhonto, Fefilova 1983).

Mogutcheva (1984) established the species Todites orulganensis from the Lower Triassic Surbeljakhskian Formation of North Verkhoyanie (Siberia).This species is similar to T. lobulatus described above, but differs by entire margined pinnules.There is no information on the in situ spores of T. orulganensis .

In general, the new species T. lobulatus differs considerably from other species of Todites known from the Upper Permian and Lower Triassic deposits of Angaraland by wider pinnules and extremely well developed pinnule lobes.

Figures

Fig.3. Todites lobulatus sp.nov.Intinskian Formation, Ufimian, Upper Permian.Holotype GIN 4846/102. A, B.General morphology of fertile pinna, bef − ore (A) and after (B) preparation; A, × 1; B, × 4. C.Two prepared sporangia; left sporangium shows a group of thick−walled cells near the stomium (dark de − pression); × 18. D. The spore of Osmundacidites type, preserved in situ, under SEM, × 800.

Fig.4. Todites lobulatus sp.nov.Intinskian Formation, Ufimian, Upper Permian.Holotype GIN 4846/102.Gen − eral morphology of a fertile pinna. Scale bar 0.5 cm.

Fig.6. Todites lobulatus sp.nov.Intinskian Formation, Ufimian, Upper Permian.Macromorphology and in situ spores, based on holotype GIN 4846/102. A, B.Fertile pinnule reconstruction, upper (adaxial, A) and lower (abaxial, B) view, numerous sporangia attached to lower side of the pinnule surface (B). C.Individual sporangium with thick−walled cells on the top area. D.Granulate microstructure of the spore surface. E.General view on the isolated spore. F, G.Spore mass extracted from the sporangia, note different sizes (relatively small spores 1 and 2 and big spores 3 and 4 of F) and different outlines of the spores (round spores 2 and ovoid 1, 3 and 4 of F; round spore 1, rounded subtriangular spore 2 and ovoid spore 3 of G).Scale bars: A, B, 5 mm; C, 0.1 mm; E, F, G, 50 µm; D, 5 µm.

Fig.7. Todites lobulatus sp.nov.Intinskian Formation, Ufimian, Upper Permian. In situ spores extracted from the holotype GIN 4846/102. A.Spore mass repeating the initial round form of sporangium, × 50. B.Several spores of different size and form, × 200. C.Spore with clearly seen laesura (left part of the photograph), × 200. D. Spore mass of ovoid form from relatively elongated sporangium, × 50. E. Spore mass in detail, × 200. F. Detail of D, × 100.

Fig.8.Spores of Osmundacidites type, extracted from the matrix containing the holotype of Todites lobulatus sp.nov.,GIN 4846/102. A, B, D, E.Different individual spores; A, B, D, × 1500; E, × 750. C, F. Granulate sculpture of spore surface, × 3000.

Fig.9.Spores of Osmundacidites type, extracted from the matrix containing the holotype of Todites lobulatus sp.nov.,GIN 4846/102. A–C.Different indi − vidual spores, × 1500. D–F. Granulate sculpture of spore surface, × 3000.