Discovery and research progress of new genera and species of ancient plants in Yima Formation

After more than 50 years of research on Yima biota, various fossils have been found continuously. The main research results and the new genera and species established by Yima Formation specimens are summarized as follows.

4.4.7. 1 ancient plants

Both the regional investigation (196 1 ~ 1964) and Kang Ming et al. (1983) have listed the fossils of Yima Formation, but their paleontology has not been specially studied and officially published. Xi Yun Hong (1977) recorded 7 genera and 8 species in the Paleontological Atlas of Central and South China (Volume III), and established a new species-Equus equisetifolia (1977). This species appeared at the top of the second (3) coal seam in the first section of Yima Formation, and Xi Yun Hong et al. (2006) collected more specimens of this species.

Ceng Yong et al. (1995) made a special study on the flora of Yima, published a monograph "Study on the Flora of Yima in Western Henan" (hereinafter referred to as "Monograph"), described 67 species belonging to 24 genera, and measured two sections in the west and middle of Yima North Open-pit Mine. This paleontological fossil has a clear horizon and is one of the most systematic paleontological research achievements of this group so far. Therefore, this book suggests that the "western section" measured by Ceng Yong et al. (1995) should be taken as the representative section (stratotype) of this group, and the middle section should be supplemented. Two new genera and three new species were established in the monograph: geminofoliolum Zeng, etc. G..gracilis Zeng et al., type species, mutatus Cladophlebis Zeng et al., Parastorgaadia (Stockmen et Mathieu) Zeng et al., a new species of mutatus cladophilbis; Mentougou, type species. The monograph also studies and analyzes the nature, comparison at home and abroad, geological age, paleoecology, paleoclimate and environment of the ancient flora of Yima (Shen et al.,1994; Ceng Yong et al., 1995, 1998).

Fig.4.88 Ginkgo biloba (according to the specimen of geological museum).

Academician Zhou Zhiyan and Academician Zhang Bole of Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences have made in-depth research on the plant fossils of Yima Formation since 1988, and many achievements in the study of the ancient plants of Yima Formation have attracted the attention of Chinese and foreign paleobotanists.

Firstly, the female reproductive organs of two Ginkgo orders in Yima, Henan Province were reported in Science Bulletin (1988). 1 new genus and 2 new species of Ginkgo biloba (Figure 4.88 to Figure 4.90) and Imai 'ai were found. Zhou Zhiyan et al. (1989) published "A Middle Jurassic silver apricot with ovule organs in Yima, Henan Province, China" in the Paleontological Atlas, and described the species of Ginkgo Yima in detail (Figure 4.9 1). 1992 published the middle Jurassic Baiera Halleisse and its associated ovule organs in China and Henan in the palaeontological atlas, and studied the relationship between B.hallei and Yimaia recurva. Zhou Zhiyan thinks that Halei leaf may be the vegetative leaf of Imai recurva Zhou et Zhang, that is, Imai Ahalei (= Imai Recurva Zhou et zhong, Baierahallei) (Figure 4.92). Zhou Zhiyan (1995) described in detail the "Middle Jurassic silver apricot fossil in Henan".

Figure 4.89 Yima Ginkgo biloba (according to Zhou Zhiyan, 1995)

Fig. 4.90 Yima Ginkgo Ginkgo Weekly Isogram (according to Zhou Zhiyan et al. 1988).

Fig. 4.9 1 Yima ginkgo restoration map (according to Zhou Zhiyan et al. , 1989)

Zhou Zhiyan (1995) pointed out that Ginkgo biloba is the oldest known fossil species with ovule organs. Its ovule organ consists of a total stalk and 2 ~ 4 wide-angle ovules protruding from the stalk, which is different from the normal mature ovule organ of Ginkgo biloba. The leaves divide deeper and the stratum corneum structure is different. However, in the anatomical structure of the ovule, there are long branches and short branches, and there are bud scales, just like Ginkgo biloba. The accompanying boat pollen is difficult to separate from living species at least in appearance.

Yimaia recurva, an extinct molecule of Ginkgoaceae, was also found in Yima Formation, slightly lower than Yimaia, accompanied by a large number of long and short branches, bud scales and pollen grains of Baiera hallei Sze. Yimaia has 8 ~ 9 ovules closely arranged at the top of the total stem, without suspensor and receptacle. There is no obvious difference between ovule structure and ginkgo biloba. It is worth noting that some pollen grains were found in the micropyle of the ovule. Their morphology also belongs to boat-shaped pollen and single-groove associated pollen. This not only recorded the extremely short pollination events in the life history of Imaya, but also confirmed that its male flower yield was very similar to that of Ginkgo biloba. Baiera Braun, a vegetative leaf, is an organ genus of Ginkgo biloba, and its related ovule organs have been recorded by Braun( 1843) and Black( 1929) respectively, but they have not been further studied. Found in Germany Fr? For a long time, the ovule organ of Baiera muensteriana (Presl) Hull (Stern-Berg, 1833) in nken area was considered as "curly young leaves", which was not confirmed until the detailed research results of Kirchner( 1992) were published. Significantly, this immature ovule organ which appeared in earlier geological age has a short funicle, which is similar to the immature specimen of recurva in Yimaia (Zhou Zhiyan et al., 1992).

The ovule organ of Ginkgo biloba has evolved from sessile type (Yima type) to sessile type (Ginkgo type), and the former is the same in morphology as the juvenile or deformed specimen of the latter, so it is speculated that the ovule organ of Ginkgo biloba belongs to the origin of supertype formation in metachronous development (Zhou Zhiyan et al.,1989; Zhou Zhiyan, 1990,1994; Zhou Zhiyan, 199 1). The same is true for vegetative leaves and megaspore membranes of Ginkgo biloba (Zhou Zhiyan, 199 1, 1993).

Figure 4.92 Imaya Harley Zhou et al. Zhang (according to Zhou Zhiyan 1995).

Zhou Zhiyan (1994) thinks that the ovule organ of live ginkgo is Yima ginkgo type. Under the pressure of k selection, the seed volume increases, which eventually leads to the decrease of seed number and the disappearance of the suspensor. Whether this K-type strategy is also the extinct survival and reproduction mode of Imaya needs further study.

According to the study of Ginkgo biloba and Ginkgo biloba, combined with the cladistic analysis of other Ginkgo biloba fossils (Zhou Zhiyan, 199 1), it is proved that Ginkgo biloba, Torrezia stanislavski, Kalkenya Arhanghelschi, Umaltolepis Krassilov, Ginkgo biloba and Ginkgo biloba are a monophyletic group. The relationship between Imaya and Ginkgo biloba is closer than that between them and any of the above genera. Zhou Zhiyan and others (1992) suggested that Ginkgo subfamily should be classified as an independent Ginkgo subfamily. Samylina( 1990) belongs to Grenana of seed beet, and may also belong to Ginkgo biloba. Its ovule organ has two vertical ovules attached to the receptacle, and the suspensor is retracted, but the leaves are extremely narrow, so it is not clear whether there are short branches. After Mesozoic, all the existing members of Ginkgo biloba have short branches (Zhou Zhiyan, 199 1).

Yao et al. (1989) reported the discovery of Sewardiodendron laxum Florin Yima, Henan Province, and published Sewardio-Denderon Laxum of Jurassic Conifer in American Journal of Botany (1998). According to the research, since the establishment of 1958, only the vegetative branches and leaves fossils have been reported, and nothing is known about their reproductive organs. Therefore, Harris did not advocate the use of Cephalotaxus, which was founded by Frohring, but classified Frohring into most specimens of Cephalotaxus and Elatocladus. A large number of well-preserved male and female cones were found in Yima Formation of Middle Jurassic in Yima, Henan Province. They were produced together with the vegetative branches of this species, and some even grew directly on leafy branches (Figure 4.93), which proved that these male and female cones and vegetative branches belonged to the same plant Sewardio-dendron laxum Florin. Cephalotaxus fortunei is the first discovery in China, and its reproductive organs have not been reported. Their findings not only show that it is inappropriate to classify this coniferous plant as Elatocladus, but also further confirm that Cephalotaxus is indeed an extinct natural genus of Cephalotaxus (Figure 4.94). So far, only one species of Peganum harmala has been found in Taxodium (Figure 4.95), so it is a monotype genus.

Fig.4.93 Three female cones growing on leafy branches (according to Yao Li et al., 1989).

Fig. 4.94 Restoration map of Suvardypine in Waldorf area of Songxi (according to Yao et al., 1989).

Zhou Zhiyan et al. (1998) published a new genus-Tian Shizhou et al. collected from Yima Formation in Review of Paleobotany and Palynology, and the new species-type species belongs to Czekanowskialean (Figure 4.96, Figure 4.97). The Four Lines Sword was originally named Shi Tian, which means a stone from heaven. At the same time, the newly discovered Phoenix microphylla (Figure 4.98) (Pseudostellaria heterophylla, a new species) is described. Zhou Zhiyan et al. (2002) published a new genus Ginkgo L. from China and Henan in Jurassic and its megaspore membrane ultrastructure, and studied the new genus and species of Ginkgo L. from Henan (Figure 4.99). The specimens are five immature cones produced by Yima Formation (the third paragraph of this book), and the pollen belongs to ". At the same time, Zhou Zhiyan and others also studied the megaspore ultrastructure of Ginkgo biloba, which is one of the few studies on megaspore ultrastructure.

The specimens of the above research results are produced in the third paragraph of this book (in the black siltstone and mudstone of the second (2)- second (1) coal seam).

The following results are the research results of the second section of this book (the gray-white sandstone section of the delta).

Fig.4.95 Styrax (according to geological museum specimen).

Zhou Zhiyan et al. (1996) published "A Jurassic Arctobaiera(Czekanowskiales) with long and short branches in Yima Formation of Middle Jurassic in China and Henan" in Paleobotanist. In this paper, a new species of Arctic arctobaierren-baoizhou et Zhang (Figure 4. 100) is described in detail. Its name comes from Zhang Renbao, Zhang Bole's father, and Sang, Zhang Bole's mother. They are all geologists and paleontologists of the 4th Team of China Jiangsu Coalfield Geology. In the exploration work, many ancient plant specimens produced in Yima coalfield of Henan Province were collected. The discovery of A.renbaoi is the only genus and species of Ginkgo in Mesozoic except A.flettii, which was established by Florin on 1936.

Figure 4.96 Tian Xian Zhang Zhou et al. (According to Zhou Zhiyan et al. 1998).

Figure 4.97 Tian Xian Zhang Zhou et al. (According to Zhou Zhiyan et al., 1998).

Fig.4.98 True Ye Haifeng (according to Zhou Zhiyan et al., 1998).

Fig.4.99 Ginkgo biloba in Kezi Prefecture, Henan Province (according to Zhou Zhiyan et al., 2002)

Zhang Bole et al. (1996) published a new species of gymnosperm Rhaphidopteris barale and its taxonomic status in the Journal of Paleontology, and described Zhang et al. (Figure 4. 10 1). Later, Zhou Zhiyan et al. (2000) published "On the Heterogeneity of Gymnosperms and Description of Two New Species of Jurassic Yima Formation in Central Henan Province" in the Journal of Paleontology No.39 (Supplement), in which Dryopteris fasciculata (Figure 4. 102) and Dryopteris parviflora were described. In the above picture, Zhou Zhiyan and others found three new species in the delta siltstone near the upper part of the second member of Yima Formation, which are the most abundant. Through the study of microstructure, the author put forward some suggestions on the attribution of some species and discussed the meaning of genera in detail. It is considered that Rhaphidopt-eris is still a morphological genus, not a natural genus, and has been classified as seed fern. Some species have many forked leaves and contained leaves.

Zhou Zhiyan et al. (200 1) published Tharrisia, a new genus of leaf organ fossils, and described three new species of Jurassic in China in Paleontology Atlas, and Tharrisia lata Zhou et al. (Figure 4. 104). At the same time, a new species, dinosaur fossil Zhou, is described (Figure 4. 105). Type species of this genus is produced in Greenland, possibly in the early Jurassic strata in Sweden, and also in the early Jurassic Tianshuigou Formation and Damaigou Formation in northwest China, Dachaidan Formation in Qinghai, Fuxian Formation, Diannawan Formation and Wenjiagou Formation in northern Shaanxi. Thirdly, the red fern (Mideng) and Zhou et al. in the lower part of Beipiao Formation in Beipiao area of Northeast China are described. Zhou Zhiyan believes that dinosaur fossils are typical species of early Jurassic in China, and they are also found in the early Jurassic strata in eastern Greenland and Sweden, in the early Jurassic strata in northeastern China, and there are also wide-tailed dinosaurs. Yima Formation in central China. The sporopollen of Yima Formation was confirmed as early and middle Jurassic (Zhang,1965; Wang Congfeng,1983; Yang et al. (1984) and Rong Shi (1994) recently considered it as early Jurassic according to sporopollen, and Chen Jinhua et al. (1997) also considered the geological age of Yima Formation as early Jurassic according to unionid. Maybe these three kinds of Tharrisia are contemporary. The geological age of this fossil needs to be determined accurately through the study of paleontological fossils and sporopollen assemblage in the future.

Fig. 4. 100 Bala Arctobaiera renbaoi Zhou et al. Zheng (according to Zhou Zhiyan et al. 1996).

In addition, barale g. et al. (1998) published "the discovery of nilsoniopteris of middle Jurassic Yima formation in central China and Henan province" on Geobios, and described a new species, nilsoniopteris Lei Bo (mulberry leaf of Bolenier) (fig. 4. 106), whose specimen was produced in yiyi. Ballari and others think that there are few cycads in Siberian flora, and N.bolei is the only representative of cycads first discovered in Yima Formation.

To sum up, from 1998 to 2002, Academician Zhou Zhiyan published influential scientific papers in famous foreign journals such as Science Bulletin, China Science and Journal of Paleontology, such as Atlas of Paleontology, Review of Paleobotany and Palynology, Paleobotanist, American Journal of Botany, and Journal of Paleontology. The Yima North Open-pit Profile has also been included in the inspection route of the International Congress of Paleobotany for many times, which has greatly improved the scientific research level and popularity of Yima biota.

Fig. 4. 10 1 fern fern with horn nail Zhang IsoZhou (according to Zhang Bole et al. 1996).

Fig. 4. 102 fan-shaped spike-shaped fern rhaphidopteris rhipidides Zhou Isogram (according to Zhou Zhiyan et al. 2000)

Deng et al. (1999) published "Discovery of a new genus of Jurassic pteridophytes and its significance" in China Science, and described the new genus-K. Jurassica Deng et Wang (6544) found in the roof horizon of the second (3) coal seam of Yima Formation. It is believed to belong to Schisandraceae. Deng pointed out that reliable Lygoderaceae plants were first discovered in the early Jurassic strata, and the new genus is only found in Yima, Henan Province in the middle Jurassic. It is not clear whether it is possible to find them on the lower floor. Because Lygodium japonicum may be one of the most primitive types of Lygodium japonicum. The discovery of this genus is of great value to the study of the origin and evolution of this family. There are not many fossils of marine plants in the early and middle Jurassic in the world, mainly distributed in tropical Europe and central China, and few in temperate Siberia. Yima flora belongs to the northern meristem flora of China, located in the southern margin of Siberian phytogeography and in the Jurassic phytogeography of northern China. There are few reports about Lygodiaceae. The discovery of new genera is of great significance for studying the characteristics and distribution of early Lygoderaceae.

Fig. 4. 103 fern Shao Hua et al.

Fig. 4. 104 begonia purpurea (according to Zhou Zhiyan, 200 1)

Fig. 4. 105 dinosaur fossils (Harris) Zhou et al. (according to Zhou Zhiyan et al. 200 1)

Fig. 4. 106 Niels Lei Bo Balalle et al. (according to Balalle g et al., 1998).

He Dechang et al. (1993) studied the silk charcoal specimens of Yima Formation. See 2.5.2.2 in this book for details.

In the investigation and evaluation of the special group, the section of Yima formation in the west of Yima formation north open pit mine was investigated, and a large number of research results about Yima formation were collected and studied. Through the comparison of historical data and field investigation results, the Yima Formation is divided into five lithologic sections, and the animal and plant fossils produced by each section are systematically counted and accurately recorded. The Yima biota and its basic framework, distribution characteristics, biota properties and paleogeographic division are summarized and put forward, and its transitional characteristics are pointed out. It is clear that the geological age of Yima Formation should be from the late Turpan-Arenian to the early Middle Jurassic. It is considered that the second (3) coal seam of Yima Formation was formed in the late Early Jurassic (Turpan-Hami period), and the second (1)-(2) coal seam and the first coal seam were formed in the early Middle Jurassic (Bahoji-Batoni period).

At the same time, the specimens collected from each lithologic section of Yima Formation were preliminarily identified. In addition to many plant fossils found in the Yima Formation, Yimabinia-Yimaxi, Nelson Yimanii (new species) and Cladosporium Yimanii (new species) symbiotic with Nelson were also discovered. And made a preliminary study on Imabinia.

Yimadou, a new species of female cone of Lotus, was found in Yima Formation of 4.4.7.2.

During the investigation and evaluation of paleontological geological relics in Henan Province in geological museum, Henan Province, many fossil specimens of branches and leaves of Nelson were collected from Yima Formation of Middle Jurassic in Yima, Henan Province, and the female reproductive organ (cone) pods were preserved with Nelson plants in China (Figure 4. 107). Beania was discovered by Carruthers (1869) in Yorkshire, England, and was later studied by soste, Gao Teng, Thomas, harish and others. It is proved that this fossil belongs to Nelson's female cone. This female cone is first discovered in China. Fossil materials are rich, which is of great significance to the division and in-depth study of lotus plants.

Xi bean elephant (fig. 4. 108).

Fig. 4. 107 China Nelson in Nelson, China, is at the same level as the leguminous genus in Imabia (according to the specimens collected in geological museum, Henan).

Female reproductive organs are spike-shaped, and spore leaves are loosely arranged. There are more than 65,438+06 ovules (seeds) with stalks growing spirally on the shaft stalks with a diameter of 2 ~ 4 mm, and the stalks and ovules hang sideways in a curved shape, with one ovule on each stalk. Ovules are oval or melon-seed-shaped, with a slightly sharp front end and a size of about 4 mm× 8 mm Some ovules have an edge of about 0.5mm and a surface with a diameter of about 0.5mm (? Tumor resin body). Ovules are easily scattered and stored separately.

The difference between the new pod bean and the fine pod bean is that there is only one ovule on each funicle of the new species, the spore leaves have no obvious shield-shaped expansion, and the planting methods are different.

Fig. 4. 108 Imagism Xi, Imagism Xi

The previous research work was helped and guided by Academician Zhou Zhiyan, and some fossil photos were taken by Dr. Wang Xin. I would like to express my heartfelt thanks here.

A list of new genera and species of Yima Formation in 4.4.7.3.

According to the fossil specimens of ancient plants in Yima Formation, 7 new genera and 19 new species are listed as follows:

New genus: 1) Dicotyledonous plant Zeng et al.,1995;

2) Parastorgaardia (stockm。 Et mathematics. ) Zeng et al.,1995;

3) Aimeiya Zhou Isozhang,1992;

4) Zhou Tianxia et al.,1998;

5) Kakenia Zhou et al., 2002;

6) Talicia Zhou et al, 2001; +0;

7) Deng Dengwang, 1999.

New Species: 1) Yima Elephant Xi Equisetum, 1977 (Figure 4.109);

Fig. 4. 109 Xi Yima equisetum (according to Zhang Xingliao et al., 2008).

2) Zhou et al.,1988;