Journ. Hattori Bot. Lab. No. 71: 377-388 (Jan. 1992)

BRYOKHUTULIINIA JURASSICA, GEN. ET SPEC. NOVA, A REMARKABLE FOSSIL MOSS FROM MONGOLIA

1 MICHAELS. IGNATOV

ABSTRACT The new genus Bryokhutuliinia is described. It includes Jurassic species B. jurassica lgnatov spec. nova from Mongolia and Cretaceous B. ingodensis (Srebrodolskaya) lgnatov comb. nova (Muscites ingodensis Srebrodolskaya) from Transbaikalia Region. The combination of the lack of costa, limbate leaf, elongated cells and distichous leaves is unique in mosses and does not allow to relate this new genus to any of extant groups. Both species of Bryokhutuliinia are known only as imprints of sterile leafy shoots.

INTRODUCTION In discussing Mesozoic leafy hepatics Schuster and Janssens ( 1989) state that so far these fossils do not enable one to elucidate the patterns of evolution: they pose only questions, they provide no meaningful answers. This evaluation is almost true also for fossil mosses. However in spite of not having evolved into recognizeable, defineable modern groups, these fossils undoubtedly provide an interesting and almost logical picture of past diversity of bryophytes and its changes toward the present. Starting with the Tertiary practically all described fossil bryophytes, both mosses and hepatics, share the features of contemporary genera (Miller 1984, Jovet-Ast 1967, Oostendorp 1987). Moreover, many of them can be attributed even to extant species. The exceptions generally depend on the presentation of fossil material: formal genera are used for remains where microstructure is either invisible, or admits too wide an interpretations. Not one of these formal genera from the Tertiary exhibits any feature or combination of features which exceeds the range of variation in extant genera. The situation with Paleozoic mosses is different: there are a sufficient number of characters which are absolutely unknown in extant groups, i.e. net nervation in Polyssaievia Neuburg or affixial leaf attachment involving the costa only and petiolated leaves in Protosphagnum Neuburg and related genera, or laminar cell dimorphism of a quite peculiar type in Protosphagnum , Vorcutannularia Neuburg, Junjagia Neuburg, Palaeosphagnum lgnatov (Neuburg 1960, Ignatov 1990). At the same time there are a number of Permian mosses with characters like those of extant taxa, but the combi­ nation of characters mostly does not enable one to attribute them to extant genera, though one can to draw certain parallels with now-existing families. Hepaticae of the Paleozoic resemble extant groups to a greater extent than mosses of the same age: their peculiarities are restricted only to a different combination of character. Maybe this fact can be explained by the tallose nature of most of these fossils, which are more difficult to classify. Leafy hepatics were described from the 1 Main Botanical Garden of the Academy of Science of USSR, 127276 Moscow, Botanicheskaya 4, USSR. 378 Journ. Hattori Bot. Lab. No. 71 I 9 9 2

Early Permian by Poulsen ( 1974) : Jungermannites sealandicus Poulsen was referred to Jungermanniales, while Gessella striata Poulsen and G. communis Poulsen, to Calob­ ryales (for G. communis sporogones were available). Gametophytically, however, Gessella is more similar to mosses because of the lanceolate, rather long leaves without differentiation into lateral leaves and underleaves. Among Mesozoic remains of bryophytes only the order Marchantiales is wide­ spread - it is represented by 14 species, 4 genera (Oostendorp 1987). All other groups of bryophytes are worse known, even than in Paleozoic. The most important, for the present discussion, are mosses and hepatics of the order Jungermanniales, which are known by a few taxa. Among mosses l Jurassic collection was attributed directly to the extant genus Sphagnum (Reissinger 1950), and Krassilov and Schuster ( 1984) mention also a still undescribed epiphytic moss resembling extant Dicranum found in the Cretaceous. Two mosses were described in separate genera - Tricostium Krassilov from the Jurassic and Yorekiella Krassilov from the Cretaceous; both are monotypic (Krassilov 1973). Some other taxa were retained in Muscites Brogn. or were described just as mosses. Of these: - Tricostium has a rather peculiar combination of characters and it is not easy to place it in any of modern families (though Pottiaceae definitely is the first candidate); - Yorekiella is a weakly understood plant; - Muscites guescelinii Townrow from Triassic of South Africa was linked to Leucodontaceae (Townrow 1959); - Muscites fontinalioides Krassilov from the Late Jurassic has no characters which would prohibit its placement just in Fontinalis Hedw.; - Muscites ura/ensis Turutanova-Ketova, nom. illeg., from Triassic is too imperfectly known; - Muscites ostracodiferus Krassilov from the Cretaceous (Krassilov 1982) does not show enough peculiarities for its systematic interpretation; - Muscites samchakianus Srebrodolskaya superficially resembles Hypnales, but the cell structure is unknown; the age was indicated by Srebrodolskaya ( 1980) as Cretaceous, but Rasnitsyn (1985) re-estimated it as Jurassic. - Muscites ingodensis Srebrodolskaya (Cretaceous), despite absence of cell peculiarities, has enough characters for separate generic placement and will be discussed in details below; - mosses from Cretaceous of Australia (Drinnan & Chambers 1986) are represented by two gametophytes of uncertain position and two sporophytes, one of which is strongly reminiscent of the Orthotrichaceae. Among Mesozoic Jungermanniales microstructure either ( 1) is not described (Triassic Jungermannites keuperianus De Gasparis, Jurassic J. gracilis (Halle) Ooste­ ndorp, Cretaceous J. cretaceous Berry, J. noterocladioides Scott, J. vetusior Saporta); (2) or inapparent (Jurassic Laticaulina papillosa Krassilov); (3) or typical jungerm­ annioid, polygonal-rounded (Jurassic Cheirorhiza brittae Krassilov); ( 4) or at least quite different from those of modern Jungermanniales - Cretaceous Diettertia monta­ nensis Brown & Robinson has elongated laminar cells, so originally it was placed in the mosses. Additional material showing more perfect preservation allowed Schuster and Janssens (1989) to clarify it systematic position and place it in Jungermanniales, but in M. S. IGNATOV: Bryokhutuliinia, a remarkable fossil moss from Mongolia 379 a separate suborder, Diettertiinae Schust. & Janssens. Thus far from the Mesozoic 1 moss from Mongolia and 2 mosses from nearby Transbaikalia were known. In 1986 in the course of collecting fossils (mostly insects) Alexander G. Ponom­ arenko collected a number of pieces of rocks with moss imprints, which he made available for study by the present author.

GEOLOGY, AGE AND PALEOENVIRONMENTS The moss fossils were found in volcanic-elastic sediments of the Ulugey formation (lower part), where coarse beds are included in lava and lava-breckchia deposits. K/Ar data from this volcanic material indicate the interval where the moss was found as 153- 138 millions YBP (Kovalenko et al., 1984). There is some evidence that the moss was buried in bottom sediments of a small temporary lake, at medium depth. The lake was surrounded by volcanos and the water may have been sometimes strongly warmed. Soon after the time when moss was abundant, the lake was completely buried by ash. The moss is associated with Brachyphyllum sp., (Cheirolepidiaceae, Gymnospermae), Equisetites sp., Baissia hirsuta Krassilov (Bennettitales). Despite the presence of some advanced taxa of insects the age of this deposit is accepted by Ponomarenko (personal communication) as the latest Late Jurassic, rather than Cretaceous (Rasnitsyn 1985).

MATERIAL AND METHODS The moss was represented by ea. 100 leafy shoots, about 10 of which are rather large, and many leaf fragments. The property of the rock is such as not to allow one to split it clearly enough to avoid numerous overlaying of one shoot by another or by rock. This make it difficult to observe macroscopic characteristics such as branching patterns and even leaves observable from base to apex are very rare (but in total about a hundred leaves more than half complete were seen). The moss is found in fairly grained tufo-argillite as imprints or imprints with scarce remnants of organic material. The latter, however, is coalified and cellular structure is mostly observed guessing from rows of minute grains of coal or by the texture of the imprint. Fortunately, on several leaves there are portions where areolation can be traced more certainly (Figs. 9- 15) - at least average size and shape of laminar cells can be judged reliably. Impressions of the organic matter are very pale, only slightly deeper in color that the rock. Photographs were made by usual camera with "bellows" and polarizating microscope; the film Mikrat-200 was used.

TAXONOMY Since the cell structure is particularly important for interpreting the systematic position of mosses its presence in the plant here described permit one to recognize this moss as a separate genus rather than place it in Muscites, which is retained for taxa of poorer preservation. Bryokhutuliinia lgnatov, gen. novum. Diagnosis: leaves distichous, remotely arranged, from the semi-appressed base reftexing up to the horizontal or squarrose; nerve lacking; border distinct all along the lamina; laminar cells elongate-rectangular. Type: Bryokhutuliinia jurassica lgnatov spec. nova. 380 Journ. Hattori Bot. Lab. No. 71 I 9 9 2

F1os. 1- 3. Bryokhutu/iinia jurassica lgnatov, gen. et spec. nova (2 left- hototype; I, 2 rigth, 3- paratypes). I- leafy stem (above) and branch (below), x 6. 2- leafy stem, X 6. 3- leafy stem, X 12. M. S. IGNATOV: Bryokhutuliinia, a remarkable fossil moss from Mongolia 381

F1os. 4-7. Bryokhutuliinia jurassica lgantov, gen. et spec. nova (5, 6- holotype; 4, 7- paratypes). 4---stem with leaves, X 14. 5---stem surface, X 49. 6-stem with leaves, X 14. 7- branch with leaves, X 14. 382 Joum. Hattori Bot. Lab. No. 71 I 9 9 2

FIGS. 8- 13. Bryokhutuliinia jurassica lgnatov, gen. et spec. nova (13-holotype; 8- 12- paratypes). 8- leaf base, X 43 . 9- lower part of leaf, X 43. 10, I I-apical parts of leaves, X 49. 12- apical part of leaf, x 43. 13- middle part of leaf, X 43. M. S. IGNATOV: Bryokhutuliinia, a remarkable fossil moss from Mongolia 383

FIGS. 14- 15 . Bryokhutuliinia jurassica lgnatov gen . et spec. nova (paratypes). 14, 15- cells of the middle part of leaf, X 82.

Diagnosis: stem 0.4-0.5 mm wide, more than 5 mm long, rarely branching. Branches spreading at 45- 60°, 0.25 mm wide. Stem leaves arranged distichously, remote, with ea. I mm between their bases, up to 5 mm long, 1.2 mm wide, from the obovate triangular base, in the uppermost portion rapidly tapering to somewhat rounded. The basal part of the stem leaf spreads from the stem at 20-35° and ends ea. I mm above the leaf insertion, where the leaf is abruptly reflexed becoming horizontal or squarrose, spreading from the stem up to 120°. Upper leaves have a longer basal portion which reflexes more abruptly. The maximal width of stem leaves is ea. at 1 mm above the leaf insertion, the narrowing towards the base is gradual, with some rounding at the most proximal part. Branch leaves are clearly arranged distichously, ea. 4 mm long, 0.8 mm wide, narrow lanceolate, gradually tapering, spread from the stem horizontally or nearly so from near the base. Leaves of the basal portion of branches as distant as above, the lowermost ea. 1.0 mm long, second - 1.5, third - 2 mm. Costa lacking. Border well-defined on all leaves, 0.04 (up to 0.05) mm wide on stem leaves, 0.03 (up to 0.04) mm wide on branch leaves. The width of the border is constant all along the lamina. Laminar cells of leaves ranges from ea. 20 µm wide in the most proximal part, up to 27- 30 (33) µm in the widest part of the leaf and again ea. 20 µm in the distal part. The length of cells is 100-150 µ m. Longitudinal walls between cells are almost straight, transverse walls are perpendicular to the leaf length (Figs. 1- 15). Type: Mongolia, Southern-Gobi Aimak, 25 km to the South of Mandal-Obo village, Khutuliin-Khira Joe., bed #391 /3. Coll. A. G. Ponomarenko (Paleontological Institute of Academy of Sciences of USSR, #4288). As holotype is selected a leafy shoot fragment with relatively well-preserved cellular 384 Journ. Hattori Bot. Lab. No. 71 I 9 9 2

structure of leaves (Figs. 2, 5, 6, 13). Other not-numerated remains on 14 pieces of rock are paratypes (those with #4288).

COMMENTS ON MORPHOLOGICAL INTERPRETATION AND PRESERVATION OF MATERIAL 1. Stems are abundantly represented, they are rather constant in their width and in the often seen sulcation of stem. The longitudinal rows on the stem (indicating the width of the cells of outer cortical layer?) are ea. 20 µm apart. 2. Branching pattern can be assumed from 2 well demarcated junctions of branch to stem, and by the number of thinner leafy shoots with almost similar leaves, which differ only in smaller size and a more clearly complanate arrangement. Since such differentiation is well-known in modern mosses and also in Muscites ingodensis (see below), this second type ofleafy shoot is assumed to represent dispersed branches of the same species. Branch position is uncertain, but there is no evidence that it was axillary, so the branching pattern is provisionally regarded as of cauline type. 3. Leaves can be assumed to be distichous judging from the 2 stems and 2 branches with very clearly visible leaf bases for an extent of 7- 9 leaves, and also by several not so well preserved specimens. The material does not permit one to distinguish whether it is true distichous (like Fissidens Hedw.) or pseudodistichous, or complanate, (as in Neckera Hedw., Plagiothecium B.S.G., etc.), the former pattern is less probable. 4. The border is treated as such, because of its exceptionally constant width, which precludes such interpretations as recurvation, incurvation or artifact. 5. Cell width can be measured readily, while length of cells is rather dubious - one can imagine cell dimensions of the available material from Figs. 14 & 15, the best preserved fragments. Also, the position of transverse partitions between cells is assumed from the material such as that shown in Figs. 14 & 15.

COMPARISON Most described Mesozoic mosses have little in common with Bryokhutu/iinia jurassica, so that comparison between them is of little use. An exception is seen in two mosses described from Transbaikalia by Srebrodolskaya ( 1980). Both have a basically similar appearance: remotely arranged on stem lanceolate leaves of more or less the same size. The deposit and preservation of these specimens are similar to those of the plants from Khutuliin. Of these, Muscites samchakianus has leaves erect-spreading with the angle of reflection 45- 60° (on stems) and up to 30° (on branches), rather dense foliation in the proximal parts of branches, leaves without any apparent border (though sometimes the leaf margin is indistinctly darker). So I consider this taxon it distinct from Bryokhuti/iinia jurassica. Muscites ingodensis is very similar with Bryokhutuliinia jurassica: this moss is also represented by very pale imprints of shoots, with distichously arranged leaves of the same shape and the same degree of reflection (up to horizontal from the semi-appressed M. S. IGNATOV: Bryokhutuliinia, a remarkable fossil moss from Mongolia 385 base). Acosta is lacking and a border is well-defined. Despite the not-preserved cell structure, these resemblances seem enough to segregate these two species into one and the same genus, with the nomenclatural resolution as follows: Bryokhutuliinia ingodensis (Srebrodolskaya) lgnatov comb. nova. Muscites ingodensis Srebrodolskaya, 1980, Trudy Vses. Geol. Inst., 204. 27, tabl. 5, fig. 2. Diagnosis: stem 0.3 mm wide, more than 25 mm long, regularly alternately branching, with interval of 1.0-2.0 (5.0) mm between the branches. Branches only slightly thinner than the stem, 0.25 mm wide, 5- 6 mm long, spreading at an angle of 60-70°, sometimes producing secondary branches spreading at an acute angle, at ea. 30°, being 0.2 mm wide 2-3 mm long. Leaves remotely arranged, with interval of 0. 7 mm between stem leaves, 0.5 mm between branch leaves. Stem leaves poorly preserved, ea. 0.5 mm wide, with widened basal part, which has an angle of ea. 30° with the stem. Branch leaves clearly distichous, 3.2- 3.5 mm long, ea. 0.5 mm wide, lanceolate with slightly widened basal part, which is of 0. 7--0.8 mm long. Branch leaves spread from the stem at 45-60°, above more or less strongly spreading up to 80-120°, with gradually tapering apex and somewhat rounded base. At the base of branch, leaves as remote as above; on the basal 0. 7 mm of branch there are two smaller leaves, while third leaf is already of normal size. Type: South Siberia, Central Transbaikalia, Elizavetinskaya depression, left bank of the Ingoda River, pad' Semen, coll. S. S. Krasinz, 1963, #1 /11219 (Museum of Central Sci. Res. Geol. Prospect, Leningrad). Jurassic (about the age see above). B. ingodensis is known only from the original locality, being represented by 5 shoots (with the same number as the holotype). B. ingodensis differs from the B. jurassica in the smaller size of the stem and leaves and by the much denser, more regular branching. The comparison of Bryokhutuliinia with extant mosses is essentially pointless, since there is no one genus or even family to accomodate it. However it seems worth to provide the comparison of combinations of characters of Bryokhutuliinia with some extant mosses. The combinaton of the well-defined border, lack of a costa and elongated cells is known in mosses only in Sphagnum. Despite strong differences in appearance contr­ asted typical expressions of Sphagnum , Bryokhutuliinia does not exhibit too clear differences from floating forms of some species of Sphagnum (especially of the S. cuspidatum-group and sect. Subsecunda). These forms can be very loosely foliated, with alternate (not fasciculate as usual) branching, isophyllous. Such a form of Sphagnum falcatum was even described in Drepanocladus (Ochyra & Bartlett, 1986) ! It is important to note that this form of Sphagnum falcatum has an areolation pattern somewhat different from that typical for Sphagnum: the cells are less flexuose, so the not-flexuose areolation of Bryokhutuliinia jurassica does not necessarily precludes it being related to Sphagnum. However some characters of Bryokhutuliinia are beyond the range of morphol­ ogical variability of Sphagnum since in the latter. - leaves are always clearly spirally arranged; - when loosely foliated, leaves of Sphagnum spread from the stem at an acute angle ( 10-30 0 ( 45) ) and are never reflexed; - the border is not so well-defined; on elongated leaves its cells are usually twice as narrow 386 Journ. Hattori Bot. Lab. No. 71 I 9 9 2 as the hyalocysts; - hyalodermis constantly developed, so a stem striation like that seen in Bryokhutuliinia seems impossible; So a close relationship of Bryokhutuliinia with Sphagnum is doubtful. In the other groups of modern mosses the combination of bordered leaf and lack (or weak) costa is very rare and in these cases laminar cells are always short (e.g. Hookeriaceae: Calyptrochaeta Desvaux; Bryaceae: Epipterygium Lind b.). Dr. Benito C. Tan after the study of photos of Bryokhutuliinia jurassica suggested that it may have an affinity with Leucophanes (Leucobryaceae), which resembles Bryokhutu/iinia in having a leaf border of Jong cells, a similar leaf size and shape (from the semi-appressed base reflexing up to horizontal). Most parts of the lamina of Leucophanes are bistratous with a "leucobryoid" structure - between the two layers of hyalocysts are included smaller chlorocysts. Such a leaf organization possibly (though not probably) can produce such imprints. Additional evidence for Leucophanes is its ecology - it is widespread along lake shores in tropical latitudes and therefore is a good candidate for fossilization. Difference of Leucophanes from Bryokhutuliinia include: - the surface cells of the lamina are quadrate to short-rectangular; - leaves are densely and spirally arranged; - branching is rare and at acute angle. These characters almost preclude the two taxa to be closely related. Lastly Bryokhutuliinia should be compared with Diettertia montanensis, a re­ markable Cretaceous moss-like hepatic. Judging from the photographs in Schuster & Janssens ( 1989) the similarity with Bryokhutuliinia is considerable: the border diff­ erentiation (on photos almost alike that of Bryokhutuliinia ); lack of costa; elongate­ rectangular cells of the only slightly smaller size than in Bryokhutuliinia; distichous leaf arrangement; transverse leaf insertion; rounded leaf base; bluntly apiculate apex; alternating branches spreading at a wide angle (60°-80°). The main difference lies in the complicate-bilobed leaves of Diettertia. However the weight of this character is quite enough to remove this bryophyte from the mosses, where it was originally placed (Brown & Robinson, 1974), to hepatics. And there would be no reason even to discuss Diettertia in comparison with the moss Bryokhu­ tuliinia if the complicate-bilobed leaves were readily visible. But it is not so. Even on the photographs provided by Shuster & J anssens ( 1989) such a leaf form is discernible only on basal portion of branches and to a less extent on one (of ten!) mature leaves. Because of some unknown reason the preservation of the dorsal (smaller in size) lobe is much poorer. This fact obliged me to re-examine all leaf bases and basal parts of branches with smaller leaves, but no traces of lobation was discernible. Combined with the not-lobate leaves, Bryokhutu/iinia does not fit current con­ ceptions of the liverworts because of the extremely long lanceolate leaves with elong­ ated cells practically up to the apex. But these peculiarities do not permit one to exclude an affinity with the Hepaticae: the lesson of Diettertia should not be forgotten. Again, the Permian Gessel/a (see above) without sporogones could be also easily M. S. IGNATOV : Bryokhutuliinia, a remarkable fossil moss from Mongolia 387 interpreted as a moss. I cannot seriously relate Bryokhutuliinia to Calobryales, since the very few extant representatives of that order are strongly unlike Bryokhutuliinia (in the small size, short leaves, quadrangular cells, etc.). Concluding, Bryokhutuliinia confirms the point that unlike Tertiary fossils Mes­ ozoic plants are usually difficult to classify in extant groups. Compared with now­ existing bryophytes it is no less peculiar (for the specialist), than Jurassic giant reptiles compared with modern lizards.

ACKNOWLEDGEMENTS I am indebted very much to Dr. Alexander G. Ponomarenko for making at my disposal these fossil specimens, for many valuable comments on the text and its supplementing with the paragraph "Geology, age and paleoenvironments"; to Dr. Rudolf M. Schuster for fruitful discussion and revising the English language of the manuscript; to Dr. Benito C. Tan for important suggestions; to Drs. Dale H. Vitt and Jan A. Janssens for reading of the manu­ script; to Drs. Dmitriy Shcherbakov and A. Czylok for the help with the photographs.

R EFERENCES Brown, J. T. & C. R. Robinson. 1974. Diettertia montanensis, gen. et spec. nov., a fossil moss from the Lower Cretaceous Kootenai Formation of Montana. Bot. Gaz. 135: 170-173. Drinnan, A. N. & T. C. Chambers. 1986. Flora of the Lower Cretaceous Koonwarra Fossil Bed (Korumburra Group), South Gippsland, Victoria. Mem. Ass. Australas. Palaeontol. 3: 1- 77. lgnatov, M. S. 1990. Upper Permian mosses from the Russian Platform. Palaeontographica, Abt. B, 217 (4- 6): 147- 189. Jovel-Ast, S. 1967. Bryophyta. In E. Boreau (ed.), Traite de paleobotanique 2: 17- 186. Mason et Cie., Paris. Kovalenko, B. I., M. S. Nagibin, G . M. Dobrov, V. I. Vertlib, M. M. Arakelyanu, V. I. Lokatin & V. S. Samojlov. 1984. Mesozojskie szczelochnye porody i svyazannoe s nimi orudnenie Mushugai­ Khudukskogo rajona Mongolii (Mesozoic alkiline rocks and connected with them ore bodies of Mushugaj- Khuduk region of Mongolia]. Izv. Akad. Nauk SSSR, ser. Geol. ( 1984), n 4: 75- 89. Krassilov, V. A. 1973. Mesozoic bryophytes from the Bureya Basin, Far East of the USSR. Palaeonto­ graphica, Abt. B, 143(5- 6): 95- 105. --. 1982. Early Cretaceous ftora of Mongolia. Palaeontographica, Abt. B, 181(1- 3): 1- 43 . --& R. M. Schuster. 1984. Paleozoic and Mesozoic fossils . In R. M. Schuster (ed.), A new manual of bryology, pp. 1172- 1193. Hattori Bot. Lab., Obi, Nichinan. Miller, N. 1984. Tertiary and Queternary fossils. In R. M. Schuster (ed.), A new manual of bryology, pp. 1194- 1232. Hattori Bot. Lab., Obi, Nichinan. Neuburg, M. F. 1960. Listostebelnye mkhi iz permskikh otlozhenij Angaridy [Mosses from the Permian deposits of Angaraland]. Trudy Geol. Inst. Akad. Nauk SSSR 19: pp. 104. Ochyra, R. & J. K. Bartlett. 1986. The identity of Drepanocladusfontina/ioides (C. Muell.) Broth. ex Par. (Bryopsida, Amblystegiaceae). N. Z. J. Bot. 24: 361 - 368. Oostendorp, C. 1987. The bryophytes of the Palaeozoic and Mesozoic. Bibi. Bryoph. 34: pp. 112. Poulsen, C. 1974. Further contributions to the knowledge of the Palaeozoic of Slagelse, n 1, estern Sealand. II: Permian rocks and fossils. Danm. Geol. Unders. 11(101): 28- 32. Rasnitsyn, A. P. (ed.) 1985. Jurskie nasekomye Sibiri i Mongolii (Jurassic insects of Siberia and Mongolia]: pp. 192. Nauka, Moscow. Reissinger, A. 1950. Die Pollenanalyse ausgedehnt auf alle Sedimentgesteine der geologischen Vergang­ enheit. Palaeontographica, Abt. B, 90: 99- 126. Schuster, R. M. & J. A. Janssens. 1989. On Diettertia, an isolated Mesozoic member of the Jungerman- 388 Journ. Hattori Bot. Lab. No. 71 I 9 9 2

niales. Rev. Palaeobot. Palynol. 57: 277- 287. Srebrodolskaya, I. N. 1980. Novye listiostebelnye mkhi iz Zabaikaliya [New Late Mesozoic mosses from the Transbaikalia Region] . Trudy Vses. Nauczno-Issl. Geol. Inst. 204: 27- 28. Townrow, A. 1959. Two Triassic bryophytes from the South.Africa. J. S. Afr. Bot. 25: 1- 22.