- Email: [email protected]
New species Dalembia jiayinensis (Magnoliopsida) from the Upper Cretaceous Yong'ancun Formation, Heilongjiang, northern China
Cretaceous Research 67 (2016) 8e15
Contents lists available at ScienceDirect
Cretaceous Research journal homepage: www.elsevier.com/locate/CretRes
New species Dalembia jiayinensis (Magnoliopsida) from the Upper Cretaceous Yong'ancun Formation, Heilongjiang, northern China Ge Sun a, b, *, Lina Golovneva c, *, Pavel Alekseev c, Fei Liang a, b, Tao Yang a, b a
College of Paleontology, Shenyang Normal University, Shenyang 110034, China Key Lab of Past Life in NE Asia, Ministry of Land & Resources, Shenyang 110034, China c Komarov Botanical Institute, Russian Academy of Sciences, St.-Petersburg 197376, Russia b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 5 April 2016 Received in revised form 20 June 2016 Accepted in revised form 24 June 2016 Available online 27 June 2016
Leaves of Dalembia jiayinensis sp. nov. are reported from the Santonian Yong'ancun Formation exposed along the Heilongjiang (Amur) River in Jiayin County, Northeast China. The leaves are compound, oddpinnate, consisting of five leaflets. Leaflets are pinnately-lobed, trilobate or unlobed, elliptic, oblong, elliptic-rhomboid or ovate in outline, with blunt or rounded apex and the leaflet base is variable being cuneate, slightly decurrent, truncate or slightly cordate and sometimes asymmetric. Margin is entire or lobed. Lobes are short, simple, decreasing upwards, with wide and rounded sinuses. Apices of the lobes are usually rounded, sometimes notched. Venation is pinnate or palmately-pinnate, craspedodromous or semi-craspedodromous. The new species D. jiayinensis extends both the geographical and stratigraphic ranges of the genus Dalembia. This is the first occurrence of Dalembia in China and the most southern and youngest (Santonian) occurrence of this genus. © 2016 Elsevier Ltd. All rights reserved.
Keywords: Dalembia Yong'ancun Formation Jiayin Heilongjiang (Amur) River Late Cretaceous Santonian Northeastern Asia
1. Introduction
2. Geological setting
The genus Dalembia was established by Lebedev and Herman (1989) for compound imparipinnate leaves with pinnately-lobed leaflets. These authors included six species in this genus: D. vachrameevii E. Lebedev et Herman, D. bolschakovae E. Lebedev et Herman, D. faradjevii E. Lebedev et Herman, D. pergamentii Herman et E. Lebedev, D. krassilovii Herman et E. Lebedev and D. comparabilis (Hollick) Herman et E. Lebedev. Members of the genus Dalembia are common components of the Cenomanian to the Coniacian floras of Northeastern Asia and Alaska (Lebedev and Herman, 1989). The systematic position of Dalembia is unclear. No similar genera are known in either fossil or living taxa. In this paper, we describe a new species Dalembia jiayinensis on the basis of leaf remains from the Upper Cretaceous Yong'ancun Formation, Jiayin County, Heilongjiang Province, Northeastern China. The geographical and stratigraphic implications of the new species are discussed.
Many new data about the stratigraphy and biota of the Upper Cretaceous deposits of the Amur (Heilongjiang) River area were obtained as a result of the activity of the international research project for the study of events surrounding the Cretaceous/Paleogene boundary, organized by the Research Center of Paleontology of Jilin University (Sun et al., 2002, 2011, 2014). The Upper Cretaceous terrigenous deposits in Jiayin area are divided into the Yong'ancun, Taipinglinchang, Yuliangzi and Furao Formations (Bureau of Geology and Mineral Resources of Heilongjiang Province, 1993). The Yong'ancun Formation is underlain by white rhyolite of the Ningyuancun Formation (the geological age is unclear) and conformably overlain by oil shale of the Taipinglinchang Formation with remains of ostracods and conchostracans. Upper member of the Taipinglinchang Formation consists of greyish-brown siltstone and fine-grained sandstone which yields abundant plant remains (Zhang, 1983; Sun et al., 2007, 2014; Golovneva et al., 2008; Quan and Sun, 2008). The thickness of the Yong'ancun Formation is about 970 m. The deposits of the Yong'ancun Formation outcrop mainly along the
* Corresponding authors. E-mail addresses: [email protected] (G. Sun), [email protected] (L. Golovneva). http://dx.doi.org/10.1016/j.cretres.2016.06.011 0195-6671/© 2016 Elsevier Ltd. All rights reserved.
G. Sun et al. / Cretaceous Research 67 (2016) 8e15
right bank of the Heilongjiang (Amur) River in the east hill of Yong'ancun villages, about 15 km to the east of Jiayin town (Fig. 1). The Yong'ancun Formation consists of alternated yellow brown cross-bedded sandstones, greenish-gray and brownish-gray siltstones and mudstones, intercalated by pebbled sandstones and conglomerates, representing alluvial-lacustrine facies of an intermontane depression in the Zeya-Bureya sedimentary basin (Bureau of Geology and Mineral Resources of Heilongjiang Province, 1993; Suzuki et al., 2004; Sun et al., 2011). In this formation plant mega- and microfossils, ostracods, bivalves, conchostracans and dinosaur footprints Jiayinosauropsis johnsoni Dong, Zhou et Wu have been found (Dong et al., 2003; Sun et al., 2007, 2011; Markevich et al., 2011). Plant fossils are rather rare in the Yong'ancun Formation. In 2002 and 2004 two fossiliferous beds (coordinates 48 500 5900 N, 130 3103000 E) were found in the bank outcrop along Heilongjiang River (Fig. 2B). The preliminary study reveals the following taxa: Asplenium dicksonianum Heer, Metasequoia sp., Taxodium sp., Sequoia sp., Cupressinocladus sp., Ginkgo ex gr. adiantoides (Ung.) Heer, Trochodendroides sp., Quereuxia angulata (Newb.) Krysht. ex Baik. In 2014, a new road construction exposed higher layers of the Yong'ancun Formation above bank outcrop (coordinates 48 500 5700 N, 130 3102400 E), that give the opportunity to gather a new collection of plant fossils in the top of the formation in several meters below the boundary with the Taipinglinchang Formation (Fig. 2A). Plant remains are more diverse at this level. Besides new species of Dalembia during field season in 2015 numerous impressions of leaves and fruits were found, including horsetails (Equisetum), ferns (Osmunda, Asplenium, Salvinia), ginkgoales (Ginkgo), conifers (Cupressinocladus, Taxodium, Metasequoia, Sequoia, Pityophyllum) and angiosperms (Trochodendroides, Nyssidium, Platanus, Arthollia, Quereuxia, and Cobbania).
9
Fig. 2. Outcrops of the Yong'ancun Formation in the east hill of Yong'ancun village: A e outcrop along the new road, upper part of the Yong'ancun Formation; B e outcrop along the right bank of the Heilongjiang (Amur) River, middle part of the Yong'ancun Formation.
Fig. 1. Map of Jiayin county, China, with Dalembia jiayinensis locality near Yong'ancun village.
10
G. Sun et al. / Cretaceous Research 67 (2016) 8e15
The Santonian age of the Yong'ancun Formation and the Campanian age of the Taipinglinchang Formation are determined on the basis of palynological data (Markevich et al., 2011; Sun et al., 2011; Liang et al., 2015). The palynoflora of the Yong'ancun Formation is named by V.S. Markevich as the Kuprianipollis santaloideseDuplosporis borealis Assemblage. This palynological assemblage is comparable to those from the upper Yaojia Formation and the lowest Nenjiang Formation in Songliao Basin, China (Liang et al., 2015). The stratigraphy of the Upper Cretaceous of Songliao Basin has been studied in high resolution with radiometric dating in recent years (Wan et al., 2013).
3. Materials and methods A total of about 50 leaflets and leaf fragments of Dalembia were collected. Among them there are only two whole compound leaves with five leaflets and several fragments with three leaflets. The specimens were photographed with a digital camera (Nikon D700). The details of fine venation were observed and photographed with a stereo microscope (Axio Imager 2). The terminology for leaf morphology follows Ellis et al. (2009). All specimens, described in this paper, are housed in the Paleontological Museum of Liaoning (PMOL) in Shenyang, China.
Fig. 3. Dalembia jiayinensis Sun et Golovneva, sp. nov., Heilongjiang province, China, the Yong'ancun Formation, Santonian: A e trilobate apical leaflet, spec. YX-007; B e compound leaf with five leaflets, spec. YX-121, holotype; C e small leaflet with undulate margin, spec. YX-020; D e leaflet with truncate base, spec. YX-021; E small leaflet with lobe-like teeth, spec. YX-005; F e trilobate apical leaflet, spec. YX-008; G e pinnately-lobed apical leaflet, spec. YX-213. Scale bar is 1 cm.
G. Sun et al. / Cretaceous Research 67 (2016) 8e15
4. Systematics Magnoliopsida incertae sedis Genus Dalembia E. Lebedev et Herman, 1989 Diagnosis (after Lebedev and Herman, 1989). Compound imparipinnate leaves, pinnately-lobed leaflets, from oval to round-
11
ovate, both small and large. Pinnate or palmately-pinnate craspedodromous venation. Inbetween secondary veins there occasionally occur fine interstitial veins going from midrib towards sinuses between lobes. Along the sinuses margin, close to it, runs a fine vein to which are joined interstitial veins and certain branches from secondary veins. Tertiary venation is from irregularly-reticulate to branched-scalariform, tertiary veins
Fig. 4. Dalembia jiayinensis Sun et Golovneva, sp. nov., Heilongjiang province, China, the Yong'ancun Formation, Santonian: A e trilobate apical leaflet, spec. YX-006; B e leaflet with undulate margin, spec. YX-134; C e apical leaflet with asymmetric base, spec. YX-012; D e lateral leaflet without lobes, spec. YX-030; E apical and lateral leaflets, petiolules with articulated surfaces, spec. YX-120; F e asymmetrical apical and small lateral leaflets, spec. YX-026; G e tooth with notched apex and thin irregularly-reticulate venation, spec. YX134; H e pinnately-lobed leaflet, spec. YX-104; I e branched-scalariform tertiary venation, spec. YX-105. Scale bar is 1 cm, for exception 4G (5 mm) and 4I (2 mm).
12
G. Sun et al. / Cretaceous Research 67 (2016) 8e15
going from secondary ones at an acute angle. Lateral lobes are in pairs. Sinuses between lobes are rounded. Large lobes are complicated by second-order lobes. In apical leaflets the lower lobes with respect to size and dissection are significantly superior to all rest. Apices of leaflets and lobes are faintly notched, truncate, rounded, not infrequently with prominent vein. Leaflet base is cordate, truncate or broadly wedge-shaped, decurrent, often asymmetric. Petiolules are fine. Type species: Dalembia vachrameevii E. Lebedev and Herman Dalembia jiayinensis Sun et Golovneva, sp. nov. (Figs. 3e6) Etymology. The species name “jiayinensis” is derived from the Jiayin town, China. Holotype. spec. YX-121, Jiayin County near Yong'ancun village, Heilongjiang, China, the Yong'ancun Formation, Upper Cretaceous (Santonian) e Fig. 3B. Material. Samples YX-005-009, YX-012, YX-020, YX-026, YX-027, YX-029, YX-030, YX-061, YX-086, YX-099, YX-104, YX-105, YX110, YX-120, YX-121, YX-124, YX-126, YX-134, YX-144, YX-161, YX-209, YX-211-215, YX-232. Diagnosis. Leaves compound, consisting of five leaflets. Leaflets pinnately-lobed, trilobate or unlobed, elliptic, oblong, ellipticrhomboid or ovate in outline, with blunt or rounded apex and cuneate, slightly decurrent, truncate or slightly cordate, sometimes asymmetric, base. Lobes short, simple, decreasing upwards, with wide and rounded sinuses. Apices of lobes usually rounded, sometimes notched or truncate. Margin entire or undulate.
Description. Leaves compound, odd-pinnate (Fig. 5D, F). The most complete specimens consist of five leaflets. Leaflets are elliptic, oblong, elliptic-rhomboid or ovate, pinnately-lobed (Figs. 3G and 4H), trilobate (Figs. 3A, B and 4A) or without lobes (Figs. 3B and 4B, D), with blunt or rounded apex and cuneate, slightly decurrent, truncate or slightly cordate, sometimes asymmetric, base. Margin is entire or undulate. Lobes are short. Apices of lobes are usually rounded, sometimes notched or truncate. The lowermost lobes are the best developed, lobe sizes decrease towards the apex of leaflet. Sinuses between lobes are wide and rounded. The main leaf axis is straight, thin, 1.5 mm in diameter. The petiolules expanded basally and have well-developed articulated surfaces (Fig. 4E). The apical leaflets are the largest, 7e11 cm long, 6e8 cm wide, and have the long thin petiolules (Figs. 3A, F, G and 4A, E, F). Lateral leaflets are opposite or subopposite, leaflets of lower pair (5e9 cm long, 3.5e6 cm wide) are bigger than leaflets of upper pair (3e6 cm long, 2e4 cm wide). Venation pinnate or palmately-pinnate, craspedodromous or semi-craspedodromous. Secondary veins are subopposite or alternate, in 6e9 pairs, subparallel, straight or slightly curved, arising from middle vein at an angle 30e50 . Lowest secondary veins are usually the longest and bear 5e6 basiscopic branches. Basal secondary veins branch from mid-vein usually above the leaflet margin. Some leaflets, especially those with cuneate decurrent base, have a pair of thin subbasal veins below basal veins (Figs. 3F and 4F). Tertiary venation is thin, branchedscalariform (Fig. 4I). Venation of higher orders is irregularly-
Fig. 5. Dalembia jiayinensis Sun et Golovneva, sp. nov., Heilongjiang province, China, the Yong'ancun Formation, Santonian: A e spec. YX-008; B e YX-012; C e spec. YX-026; D eholotype, spec. YX-121; E spec. YX-120; F e spec. YX-196; G e spec. YX-006.
G. Sun et al. / Cretaceous Research 67 (2016) 8e15
Fig. 6. Dalembia jiayinensis Sun et Golovneva, sp. nov., Heilongjiang province, China, the Yong'ancun Formation, Santonian. Details of venation, spec. YX-134.
13
Dalembia comparabilis (Hollick) E. Lebedev et Herman has usually two pairs of lobes, but it differs from D. jiayinensis by leaflet shape and more significant dissection of lamina. Leaflets in D. comparabilis are rounded or oval with deep sinuses between lobes (1/2 from leaflet width), while in D. jiayinensis leaflets more elongated with short lobes and shallow sinuses (depth of sinuses less than 1/3 of leaflet width). The reconstruction of compound leaf of Dalembia jiayinensis is shown in Fig. 7. The earliest occurrence of Dalembia was documented from the Cenomanian-lower Turonian deposits of the upper member of the Krivorechenskaya Formation, Grebenka River basin, Northeastern Russia (Lebedev and Herman, 1989), where remains of D. vachrameevii, D. pergamentii and D. faradjevii were found (Fig. 8). Besides that, D. pergamentii was discovered from the TuronianConiacian deposits of the Valizhgen Formation at Northeastern Kamchatka and Yelistratov peninsula in Penzhina Bay area, from Vetvinskaya Unit in the Penzhina and Oklan rivers interfluve (Herman and Sokolova, 2016) and from the Turonian-Coniacian deposits of the Arman Formation of Arman River basin (Herman et al., 2012, 2016). Dalembia bolschakovae is known only from one locality in Uliya River basin from the deposits of the Amka Formation, which is assigned now to the Coniacian (Golovneva, 2013). Dalembia krassilovii occurs in the uppermost part of the Valizhgen Formation, assigned to the Coniacian-(?)lower Santonian. This species was also distributed in the Turonian-Coniacian floras of Sakhalin. Dalembia comparabilis was first described by Hollick (1930) as Cissites comparabilis Hollick from the Upper Cretaceous deposits of Yukon River, Alaska peninsula. The age of the Kaltag and Melozi
reticulate (Figs. 4G and 6). It is thin and often poorly preserved.
5. Discussion Compared with other species of Dalembia, the new species differs most in less developed lobes and also in predominantly cuneate decurrent base of the leaflets. Its leaflets have one or two pairs of short lobes, lacking additional lobes of second order. Sometimes leaflets may be unlobed with entire or undulate margin. Basal veins and the lowermost pair of lobes are usually the most developed. The type species D. vachrameevii E. Lebedev et Herman has leaflets with 2e4 pairs of longer lobes and basal lobes with subsidiary small lobes and large teeth. Dalembia bolschakovae E. Lebedev et Herman has some smaller leaflets (6e11 cm long) than D. jiayinensis, with 4e5 pairs of rather short lobes. The second pair of secondary veins is the longest. Leaves of D. faradjevii E. Lebedev et Herman consists of nine small leaflets (up to 4 cm long) with 4e5 pairs of lobes. Apical leaflet of D. pergamentii Herman et E. Lebedev is characterized by 4e5 pairs of lobes with numerous secondary lobes and rounded teeth. The size and the amount of dissection of lobes decrease towards leaflet apex. Lateral leaflets have 5e7 pairs of lobes, from which second or third pair are the best developed. The depth of sinuses dividing the lobes corresponds to 1/3e2/3 of leaflet width. In the whole, D. pergamentii differs in the absence of notching in the lobe apices and in significant dissection of lobes and leaflets. Dalembia krassilovii Herman et E. Lebedev has 4e5 pairs of lobes and is characterized by significantly narrower elongated lobes and by prominently decurrent base.
Fig. 7. Reconstruction of compound leaf of Dalembia jiayinensis Sun et Golovneva, sp. nov.
14
G. Sun et al. / Cretaceous Research 67 (2016) 8e15
Fig. 8. Distribution of Dalembia species in Northern Pacific region.
formations is now estimated as Cenomanian or late Albian-early Turonian (Patton, 1973). 6. Conclusions Members of Dalembia are common components found in Cenomanian to Santonian floras from areas surrounding the northern part of the Pacific Ocean. The new species D. jiayinensis extends the geographical and stratigraphic ranges of the genus Dalembia. It represents the youngest (Santonian) and the most southern and western occurrence of this genus. Acknowledgments The authors thank the financial supports of the Project 111 of China, the Key-Lab of Evolution of Past Life in NE Asia, MOEC, the Project 2015FY310100-15 of the MOST, China and the project 1504-05688a of the Russian Foundation for Basic Research. We are grateful to Chinese colleagues Li L., Chen F., Yu P., from Jilin University and Shenyang Normal University; China; and the kind assistance of the Jiayin County Government and the Dinosaur Museum of Jiayin, China. We are sincerely grateful to Alexei Herman, David Dilcher and an anonymous reviewer for their helpful comments during the preparation of the manuscript. References Bureau of Geology and Mineral Resources of Heilongjiang Province, 1993. Regional Geology of Heilongjiang Province. Geol. Publ. House, Beijing (in Chinese with English abstract). Dong, Z.M., Zhou, Z.L., Wu, Y., 2003. Note on a hadrosaur footprint from Heilongjiang River area of China. Vertebrata Pal Asiatica 41 (4), 324e326. Ellis, B., Daly, D.C., Hickey, L.J., Mitchell, J.V., Johnson, K.R., Wilf, P., Wing, S.L., 2009. Manual of Leaf Architecture. Cornell University Press, New York.
Golovneva, L.B., 2013. New data about the Late Cretaceous floras of the Ulya depression (western coast of Sea of Okhotsk). Palaeobotany 4, 148e167 (in Russian). Golovneva, L., Sun, G., Bugdaeva, E.V., 2008. Campanian flora of the Bureya River basin (Late Cretaceous of the Amur region). Paleontological Journal 42, 554e567. Herman, A.B., Sokolova, A.B., 2016. Late Cretaceous Kholokhovchan flora of Northeastern Asia: composition, age and fossil plant descriptions. Cretaceous Research 59, 249e271. Herman, A.B., Golovneva, L.B., Shchepetov, S.V., 2012. Late Cretaceous Arman Flora of the Magadan District: composition, age and new plant species. Paleontological Journal 46 (6), 630e641. Herman, A.B., Golovneva, L.B., Shczepetov, S.V., Grabovsky, A.A., 2016. The Late Cretaceous Arman Flora from the Magadan Region, Northeastern Russia. Stratigraphy and Geological Correlation 24 (7) (in press). Hollick, A., 1930. The Upper Cretaceous floras of Alaska. USGS Professional Paper 159, 1e123. Lebedev, E.L., Herman, A.B., 1989. A new genus of cretaceous angiosperms d Dalembia. Review of Palaeobotany and Palynology 59, 77e91. Liang, F., Zhang, S.Q., Markevich, V., Bugdaeva, E., Sun, G., 2015. New data on palynology of lower part of Yongancun Formation (Upper Cretaceous) in Jiayin of Heilongjiang, Zeya-Bureya Basin, China. Pacific Geology 34 (3), 1e9. Markevich, V., Bugdaeva, E., Ashraf, A.R., Sun, G., 2011. Boundary of Cretaceous and Paleogene continental deposits in Zeya-Bureya Basin, Amur (Heilongjiang) River region. Global Geology 14 (3), 144e159. Patton Jr., W.W., 1973. Reconnaissance geology of the Northern Yukon-Koyukuk Province, Alaska. USGS Professional Paper 774-A, 1e17. Quan, C., Sun, G., 2008. Late Cretaceous aquatic angiosperms from Jiayin, Heilongjiang, Northeast China. Acta Geologica Sinica (English Edition) 82, 1133e1140. Sun, G., Akhmetiev, M., Dong, Z.M., Ashraf, A.R., Sun, Y.W., Bugdaeva, E., Dilcher, D.L., Golovneva, L., Harding, I., Johnson, K., Kezina, T., Kodrul, T., Lu, J.S., Markevich, V., Nishida, H., Okada, H., Park, S.O., Sun, C.L., Xiong, X.Z., Xing, Y.L., Zhou, Z.L., 2002. In search of the Cretaceous-Tertiary Boundary in Heilongjiang River Area of China. Journal of Geoscientific Research in Northeast Asia 5 (2), 105e113. Sun, G., Akhmetiev, M.A., Golovneva, L., Bugdaeva, E., Quan, C., Kodrul, T., Nishida, H., Sun, Y., Sun, C., Johnson, K., Dilcher, D., 2007. Late Cretaceous Plants from Jiayin along Heilongjiang River, Northeast China. CFS Courier Forschungsinstitut Senckenberg 258, 75e83. Sun, G., Akhmetiev, M., Markevich, V., Ashraf, A.R., Bugdaeva, E., Godefroit, P., Bolotsky, Yu, Dong, Z.M., Golovneva, L., Yang, H.X., Sun, C.L., Sun, Y.W., Quan, C., Kodrul, T., Kezina, T., Johnson, K., Nishida, H., Dilcher, D.L., Harding, I., Chen, Y.J.,
G. Sun et al. / Cretaceous Research 67 (2016) 8e15 2011. Late Cretaceous biota and Cretaceous-Paleogene (K-Pg) boundary in Jiayin of Heilongjiang, China. Global Geology 14 (3), 115e143. Sun, G., Dong, Z.M., Akhmetiev, M., Markevich, V., Ashraf, A.R., Godefroit, P., Dilcher, D.L., Sun, C.L., Sun, Y.W., Quan, C., Golovneva, L., Bugdaeva, E., Bolotsky, Yu, Suzuki, S., Kodrul, T., Nishida, H., Kezina, T., Harding, I., Yang, H.X., Ge, W.C., Chen, Y.J., Yang, T., 2014. Late Cretaceous-Paleocene Biota and the K-Pg Boundary from Jiayin of Heilongjiang, China with Discussion on the Extinction of Dinosaurs. Shanghai Sci. Techn. Educ. Publishing House, Shanghai.
15
Suzuki, S., Ashraf, A.R., Okada, H., 2004. Sedimentary facies of Maastrichtian to Danian deposits in Amur River area, Russian Far East. Journal of Geoscientific Research in Northeast Asia 7 (2), 149e155. Wan, X., Zhao, J., Scott, R.W., Wang, P., Feng, Z., Huang, Q., Xi, D., 2013. Late Cretaceous stratigraphy, Songliao Basin, NE China: SK1 cores. Palaeogeography, Palaeoclimatology, Palaeoecology 385, 31e43. Zhang, Z.C., 1983. The Upper Cretaceous fossil plants from Jiayin Region, Northern Heilongjiang. Professional Papers of Stratigraphy and Palaeonology 11, 111e132.
Contents lists available at ScienceDirect
Cretaceous Research journal homepage: www.elsevier.com/locate/CretRes
New species Dalembia jiayinensis (Magnoliopsida) from the Upper Cretaceous Yong'ancun Formation, Heilongjiang, northern China Ge Sun a, b, *, Lina Golovneva c, *, Pavel Alekseev c, Fei Liang a, b, Tao Yang a, b a
College of Paleontology, Shenyang Normal University, Shenyang 110034, China Key Lab of Past Life in NE Asia, Ministry of Land & Resources, Shenyang 110034, China c Komarov Botanical Institute, Russian Academy of Sciences, St.-Petersburg 197376, Russia b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 5 April 2016 Received in revised form 20 June 2016 Accepted in revised form 24 June 2016 Available online 27 June 2016
Leaves of Dalembia jiayinensis sp. nov. are reported from the Santonian Yong'ancun Formation exposed along the Heilongjiang (Amur) River in Jiayin County, Northeast China. The leaves are compound, oddpinnate, consisting of five leaflets. Leaflets are pinnately-lobed, trilobate or unlobed, elliptic, oblong, elliptic-rhomboid or ovate in outline, with blunt or rounded apex and the leaflet base is variable being cuneate, slightly decurrent, truncate or slightly cordate and sometimes asymmetric. Margin is entire or lobed. Lobes are short, simple, decreasing upwards, with wide and rounded sinuses. Apices of the lobes are usually rounded, sometimes notched. Venation is pinnate or palmately-pinnate, craspedodromous or semi-craspedodromous. The new species D. jiayinensis extends both the geographical and stratigraphic ranges of the genus Dalembia. This is the first occurrence of Dalembia in China and the most southern and youngest (Santonian) occurrence of this genus. © 2016 Elsevier Ltd. All rights reserved.
Keywords: Dalembia Yong'ancun Formation Jiayin Heilongjiang (Amur) River Late Cretaceous Santonian Northeastern Asia
1. Introduction
2. Geological setting
The genus Dalembia was established by Lebedev and Herman (1989) for compound imparipinnate leaves with pinnately-lobed leaflets. These authors included six species in this genus: D. vachrameevii E. Lebedev et Herman, D. bolschakovae E. Lebedev et Herman, D. faradjevii E. Lebedev et Herman, D. pergamentii Herman et E. Lebedev, D. krassilovii Herman et E. Lebedev and D. comparabilis (Hollick) Herman et E. Lebedev. Members of the genus Dalembia are common components of the Cenomanian to the Coniacian floras of Northeastern Asia and Alaska (Lebedev and Herman, 1989). The systematic position of Dalembia is unclear. No similar genera are known in either fossil or living taxa. In this paper, we describe a new species Dalembia jiayinensis on the basis of leaf remains from the Upper Cretaceous Yong'ancun Formation, Jiayin County, Heilongjiang Province, Northeastern China. The geographical and stratigraphic implications of the new species are discussed.
Many new data about the stratigraphy and biota of the Upper Cretaceous deposits of the Amur (Heilongjiang) River area were obtained as a result of the activity of the international research project for the study of events surrounding the Cretaceous/Paleogene boundary, organized by the Research Center of Paleontology of Jilin University (Sun et al., 2002, 2011, 2014). The Upper Cretaceous terrigenous deposits in Jiayin area are divided into the Yong'ancun, Taipinglinchang, Yuliangzi and Furao Formations (Bureau of Geology and Mineral Resources of Heilongjiang Province, 1993). The Yong'ancun Formation is underlain by white rhyolite of the Ningyuancun Formation (the geological age is unclear) and conformably overlain by oil shale of the Taipinglinchang Formation with remains of ostracods and conchostracans. Upper member of the Taipinglinchang Formation consists of greyish-brown siltstone and fine-grained sandstone which yields abundant plant remains (Zhang, 1983; Sun et al., 2007, 2014; Golovneva et al., 2008; Quan and Sun, 2008). The thickness of the Yong'ancun Formation is about 970 m. The deposits of the Yong'ancun Formation outcrop mainly along the
* Corresponding authors. E-mail addresses: [email protected] (G. Sun), [email protected] (L. Golovneva). http://dx.doi.org/10.1016/j.cretres.2016.06.011 0195-6671/© 2016 Elsevier Ltd. All rights reserved.
G. Sun et al. / Cretaceous Research 67 (2016) 8e15
right bank of the Heilongjiang (Amur) River in the east hill of Yong'ancun villages, about 15 km to the east of Jiayin town (Fig. 1). The Yong'ancun Formation consists of alternated yellow brown cross-bedded sandstones, greenish-gray and brownish-gray siltstones and mudstones, intercalated by pebbled sandstones and conglomerates, representing alluvial-lacustrine facies of an intermontane depression in the Zeya-Bureya sedimentary basin (Bureau of Geology and Mineral Resources of Heilongjiang Province, 1993; Suzuki et al., 2004; Sun et al., 2011). In this formation plant mega- and microfossils, ostracods, bivalves, conchostracans and dinosaur footprints Jiayinosauropsis johnsoni Dong, Zhou et Wu have been found (Dong et al., 2003; Sun et al., 2007, 2011; Markevich et al., 2011). Plant fossils are rather rare in the Yong'ancun Formation. In 2002 and 2004 two fossiliferous beds (coordinates 48 500 5900 N, 130 3103000 E) were found in the bank outcrop along Heilongjiang River (Fig. 2B). The preliminary study reveals the following taxa: Asplenium dicksonianum Heer, Metasequoia sp., Taxodium sp., Sequoia sp., Cupressinocladus sp., Ginkgo ex gr. adiantoides (Ung.) Heer, Trochodendroides sp., Quereuxia angulata (Newb.) Krysht. ex Baik. In 2014, a new road construction exposed higher layers of the Yong'ancun Formation above bank outcrop (coordinates 48 500 5700 N, 130 3102400 E), that give the opportunity to gather a new collection of plant fossils in the top of the formation in several meters below the boundary with the Taipinglinchang Formation (Fig. 2A). Plant remains are more diverse at this level. Besides new species of Dalembia during field season in 2015 numerous impressions of leaves and fruits were found, including horsetails (Equisetum), ferns (Osmunda, Asplenium, Salvinia), ginkgoales (Ginkgo), conifers (Cupressinocladus, Taxodium, Metasequoia, Sequoia, Pityophyllum) and angiosperms (Trochodendroides, Nyssidium, Platanus, Arthollia, Quereuxia, and Cobbania).
9
Fig. 2. Outcrops of the Yong'ancun Formation in the east hill of Yong'ancun village: A e outcrop along the new road, upper part of the Yong'ancun Formation; B e outcrop along the right bank of the Heilongjiang (Amur) River, middle part of the Yong'ancun Formation.
Fig. 1. Map of Jiayin county, China, with Dalembia jiayinensis locality near Yong'ancun village.
10
G. Sun et al. / Cretaceous Research 67 (2016) 8e15
The Santonian age of the Yong'ancun Formation and the Campanian age of the Taipinglinchang Formation are determined on the basis of palynological data (Markevich et al., 2011; Sun et al., 2011; Liang et al., 2015). The palynoflora of the Yong'ancun Formation is named by V.S. Markevich as the Kuprianipollis santaloideseDuplosporis borealis Assemblage. This palynological assemblage is comparable to those from the upper Yaojia Formation and the lowest Nenjiang Formation in Songliao Basin, China (Liang et al., 2015). The stratigraphy of the Upper Cretaceous of Songliao Basin has been studied in high resolution with radiometric dating in recent years (Wan et al., 2013).
3. Materials and methods A total of about 50 leaflets and leaf fragments of Dalembia were collected. Among them there are only two whole compound leaves with five leaflets and several fragments with three leaflets. The specimens were photographed with a digital camera (Nikon D700). The details of fine venation were observed and photographed with a stereo microscope (Axio Imager 2). The terminology for leaf morphology follows Ellis et al. (2009). All specimens, described in this paper, are housed in the Paleontological Museum of Liaoning (PMOL) in Shenyang, China.
Fig. 3. Dalembia jiayinensis Sun et Golovneva, sp. nov., Heilongjiang province, China, the Yong'ancun Formation, Santonian: A e trilobate apical leaflet, spec. YX-007; B e compound leaf with five leaflets, spec. YX-121, holotype; C e small leaflet with undulate margin, spec. YX-020; D e leaflet with truncate base, spec. YX-021; E small leaflet with lobe-like teeth, spec. YX-005; F e trilobate apical leaflet, spec. YX-008; G e pinnately-lobed apical leaflet, spec. YX-213. Scale bar is 1 cm.
G. Sun et al. / Cretaceous Research 67 (2016) 8e15
4. Systematics Magnoliopsida incertae sedis Genus Dalembia E. Lebedev et Herman, 1989 Diagnosis (after Lebedev and Herman, 1989). Compound imparipinnate leaves, pinnately-lobed leaflets, from oval to round-
11
ovate, both small and large. Pinnate or palmately-pinnate craspedodromous venation. Inbetween secondary veins there occasionally occur fine interstitial veins going from midrib towards sinuses between lobes. Along the sinuses margin, close to it, runs a fine vein to which are joined interstitial veins and certain branches from secondary veins. Tertiary venation is from irregularly-reticulate to branched-scalariform, tertiary veins
Fig. 4. Dalembia jiayinensis Sun et Golovneva, sp. nov., Heilongjiang province, China, the Yong'ancun Formation, Santonian: A e trilobate apical leaflet, spec. YX-006; B e leaflet with undulate margin, spec. YX-134; C e apical leaflet with asymmetric base, spec. YX-012; D e lateral leaflet without lobes, spec. YX-030; E apical and lateral leaflets, petiolules with articulated surfaces, spec. YX-120; F e asymmetrical apical and small lateral leaflets, spec. YX-026; G e tooth with notched apex and thin irregularly-reticulate venation, spec. YX134; H e pinnately-lobed leaflet, spec. YX-104; I e branched-scalariform tertiary venation, spec. YX-105. Scale bar is 1 cm, for exception 4G (5 mm) and 4I (2 mm).
12
G. Sun et al. / Cretaceous Research 67 (2016) 8e15
going from secondary ones at an acute angle. Lateral lobes are in pairs. Sinuses between lobes are rounded. Large lobes are complicated by second-order lobes. In apical leaflets the lower lobes with respect to size and dissection are significantly superior to all rest. Apices of leaflets and lobes are faintly notched, truncate, rounded, not infrequently with prominent vein. Leaflet base is cordate, truncate or broadly wedge-shaped, decurrent, often asymmetric. Petiolules are fine. Type species: Dalembia vachrameevii E. Lebedev and Herman Dalembia jiayinensis Sun et Golovneva, sp. nov. (Figs. 3e6) Etymology. The species name “jiayinensis” is derived from the Jiayin town, China. Holotype. spec. YX-121, Jiayin County near Yong'ancun village, Heilongjiang, China, the Yong'ancun Formation, Upper Cretaceous (Santonian) e Fig. 3B. Material. Samples YX-005-009, YX-012, YX-020, YX-026, YX-027, YX-029, YX-030, YX-061, YX-086, YX-099, YX-104, YX-105, YX110, YX-120, YX-121, YX-124, YX-126, YX-134, YX-144, YX-161, YX-209, YX-211-215, YX-232. Diagnosis. Leaves compound, consisting of five leaflets. Leaflets pinnately-lobed, trilobate or unlobed, elliptic, oblong, ellipticrhomboid or ovate in outline, with blunt or rounded apex and cuneate, slightly decurrent, truncate or slightly cordate, sometimes asymmetric, base. Lobes short, simple, decreasing upwards, with wide and rounded sinuses. Apices of lobes usually rounded, sometimes notched or truncate. Margin entire or undulate.
Description. Leaves compound, odd-pinnate (Fig. 5D, F). The most complete specimens consist of five leaflets. Leaflets are elliptic, oblong, elliptic-rhomboid or ovate, pinnately-lobed (Figs. 3G and 4H), trilobate (Figs. 3A, B and 4A) or without lobes (Figs. 3B and 4B, D), with blunt or rounded apex and cuneate, slightly decurrent, truncate or slightly cordate, sometimes asymmetric, base. Margin is entire or undulate. Lobes are short. Apices of lobes are usually rounded, sometimes notched or truncate. The lowermost lobes are the best developed, lobe sizes decrease towards the apex of leaflet. Sinuses between lobes are wide and rounded. The main leaf axis is straight, thin, 1.5 mm in diameter. The petiolules expanded basally and have well-developed articulated surfaces (Fig. 4E). The apical leaflets are the largest, 7e11 cm long, 6e8 cm wide, and have the long thin petiolules (Figs. 3A, F, G and 4A, E, F). Lateral leaflets are opposite or subopposite, leaflets of lower pair (5e9 cm long, 3.5e6 cm wide) are bigger than leaflets of upper pair (3e6 cm long, 2e4 cm wide). Venation pinnate or palmately-pinnate, craspedodromous or semi-craspedodromous. Secondary veins are subopposite or alternate, in 6e9 pairs, subparallel, straight or slightly curved, arising from middle vein at an angle 30e50 . Lowest secondary veins are usually the longest and bear 5e6 basiscopic branches. Basal secondary veins branch from mid-vein usually above the leaflet margin. Some leaflets, especially those with cuneate decurrent base, have a pair of thin subbasal veins below basal veins (Figs. 3F and 4F). Tertiary venation is thin, branchedscalariform (Fig. 4I). Venation of higher orders is irregularly-
Fig. 5. Dalembia jiayinensis Sun et Golovneva, sp. nov., Heilongjiang province, China, the Yong'ancun Formation, Santonian: A e spec. YX-008; B e YX-012; C e spec. YX-026; D eholotype, spec. YX-121; E spec. YX-120; F e spec. YX-196; G e spec. YX-006.
G. Sun et al. / Cretaceous Research 67 (2016) 8e15
Fig. 6. Dalembia jiayinensis Sun et Golovneva, sp. nov., Heilongjiang province, China, the Yong'ancun Formation, Santonian. Details of venation, spec. YX-134.
13
Dalembia comparabilis (Hollick) E. Lebedev et Herman has usually two pairs of lobes, but it differs from D. jiayinensis by leaflet shape and more significant dissection of lamina. Leaflets in D. comparabilis are rounded or oval with deep sinuses between lobes (1/2 from leaflet width), while in D. jiayinensis leaflets more elongated with short lobes and shallow sinuses (depth of sinuses less than 1/3 of leaflet width). The reconstruction of compound leaf of Dalembia jiayinensis is shown in Fig. 7. The earliest occurrence of Dalembia was documented from the Cenomanian-lower Turonian deposits of the upper member of the Krivorechenskaya Formation, Grebenka River basin, Northeastern Russia (Lebedev and Herman, 1989), where remains of D. vachrameevii, D. pergamentii and D. faradjevii were found (Fig. 8). Besides that, D. pergamentii was discovered from the TuronianConiacian deposits of the Valizhgen Formation at Northeastern Kamchatka and Yelistratov peninsula in Penzhina Bay area, from Vetvinskaya Unit in the Penzhina and Oklan rivers interfluve (Herman and Sokolova, 2016) and from the Turonian-Coniacian deposits of the Arman Formation of Arman River basin (Herman et al., 2012, 2016). Dalembia bolschakovae is known only from one locality in Uliya River basin from the deposits of the Amka Formation, which is assigned now to the Coniacian (Golovneva, 2013). Dalembia krassilovii occurs in the uppermost part of the Valizhgen Formation, assigned to the Coniacian-(?)lower Santonian. This species was also distributed in the Turonian-Coniacian floras of Sakhalin. Dalembia comparabilis was first described by Hollick (1930) as Cissites comparabilis Hollick from the Upper Cretaceous deposits of Yukon River, Alaska peninsula. The age of the Kaltag and Melozi
reticulate (Figs. 4G and 6). It is thin and often poorly preserved.
5. Discussion Compared with other species of Dalembia, the new species differs most in less developed lobes and also in predominantly cuneate decurrent base of the leaflets. Its leaflets have one or two pairs of short lobes, lacking additional lobes of second order. Sometimes leaflets may be unlobed with entire or undulate margin. Basal veins and the lowermost pair of lobes are usually the most developed. The type species D. vachrameevii E. Lebedev et Herman has leaflets with 2e4 pairs of longer lobes and basal lobes with subsidiary small lobes and large teeth. Dalembia bolschakovae E. Lebedev et Herman has some smaller leaflets (6e11 cm long) than D. jiayinensis, with 4e5 pairs of rather short lobes. The second pair of secondary veins is the longest. Leaves of D. faradjevii E. Lebedev et Herman consists of nine small leaflets (up to 4 cm long) with 4e5 pairs of lobes. Apical leaflet of D. pergamentii Herman et E. Lebedev is characterized by 4e5 pairs of lobes with numerous secondary lobes and rounded teeth. The size and the amount of dissection of lobes decrease towards leaflet apex. Lateral leaflets have 5e7 pairs of lobes, from which second or third pair are the best developed. The depth of sinuses dividing the lobes corresponds to 1/3e2/3 of leaflet width. In the whole, D. pergamentii differs in the absence of notching in the lobe apices and in significant dissection of lobes and leaflets. Dalembia krassilovii Herman et E. Lebedev has 4e5 pairs of lobes and is characterized by significantly narrower elongated lobes and by prominently decurrent base.
Fig. 7. Reconstruction of compound leaf of Dalembia jiayinensis Sun et Golovneva, sp. nov.
14
G. Sun et al. / Cretaceous Research 67 (2016) 8e15
Fig. 8. Distribution of Dalembia species in Northern Pacific region.
formations is now estimated as Cenomanian or late Albian-early Turonian (Patton, 1973). 6. Conclusions Members of Dalembia are common components found in Cenomanian to Santonian floras from areas surrounding the northern part of the Pacific Ocean. The new species D. jiayinensis extends the geographical and stratigraphic ranges of the genus Dalembia. It represents the youngest (Santonian) and the most southern and western occurrence of this genus. Acknowledgments The authors thank the financial supports of the Project 111 of China, the Key-Lab of Evolution of Past Life in NE Asia, MOEC, the Project 2015FY310100-15 of the MOST, China and the project 1504-05688a of the Russian Foundation for Basic Research. We are grateful to Chinese colleagues Li L., Chen F., Yu P., from Jilin University and Shenyang Normal University; China; and the kind assistance of the Jiayin County Government and the Dinosaur Museum of Jiayin, China. We are sincerely grateful to Alexei Herman, David Dilcher and an anonymous reviewer for their helpful comments during the preparation of the manuscript. References Bureau of Geology and Mineral Resources of Heilongjiang Province, 1993. Regional Geology of Heilongjiang Province. Geol. Publ. House, Beijing (in Chinese with English abstract). Dong, Z.M., Zhou, Z.L., Wu, Y., 2003. Note on a hadrosaur footprint from Heilongjiang River area of China. Vertebrata Pal Asiatica 41 (4), 324e326. Ellis, B., Daly, D.C., Hickey, L.J., Mitchell, J.V., Johnson, K.R., Wilf, P., Wing, S.L., 2009. Manual of Leaf Architecture. Cornell University Press, New York.
Golovneva, L.B., 2013. New data about the Late Cretaceous floras of the Ulya depression (western coast of Sea of Okhotsk). Palaeobotany 4, 148e167 (in Russian). Golovneva, L., Sun, G., Bugdaeva, E.V., 2008. Campanian flora of the Bureya River basin (Late Cretaceous of the Amur region). Paleontological Journal 42, 554e567. Herman, A.B., Sokolova, A.B., 2016. Late Cretaceous Kholokhovchan flora of Northeastern Asia: composition, age and fossil plant descriptions. Cretaceous Research 59, 249e271. Herman, A.B., Golovneva, L.B., Shchepetov, S.V., 2012. Late Cretaceous Arman Flora of the Magadan District: composition, age and new plant species. Paleontological Journal 46 (6), 630e641. Herman, A.B., Golovneva, L.B., Shczepetov, S.V., Grabovsky, A.A., 2016. The Late Cretaceous Arman Flora from the Magadan Region, Northeastern Russia. Stratigraphy and Geological Correlation 24 (7) (in press). Hollick, A., 1930. The Upper Cretaceous floras of Alaska. USGS Professional Paper 159, 1e123. Lebedev, E.L., Herman, A.B., 1989. A new genus of cretaceous angiosperms d Dalembia. Review of Palaeobotany and Palynology 59, 77e91. Liang, F., Zhang, S.Q., Markevich, V., Bugdaeva, E., Sun, G., 2015. New data on palynology of lower part of Yongancun Formation (Upper Cretaceous) in Jiayin of Heilongjiang, Zeya-Bureya Basin, China. Pacific Geology 34 (3), 1e9. Markevich, V., Bugdaeva, E., Ashraf, A.R., Sun, G., 2011. Boundary of Cretaceous and Paleogene continental deposits in Zeya-Bureya Basin, Amur (Heilongjiang) River region. Global Geology 14 (3), 144e159. Patton Jr., W.W., 1973. Reconnaissance geology of the Northern Yukon-Koyukuk Province, Alaska. USGS Professional Paper 774-A, 1e17. Quan, C., Sun, G., 2008. Late Cretaceous aquatic angiosperms from Jiayin, Heilongjiang, Northeast China. Acta Geologica Sinica (English Edition) 82, 1133e1140. Sun, G., Akhmetiev, M., Dong, Z.M., Ashraf, A.R., Sun, Y.W., Bugdaeva, E., Dilcher, D.L., Golovneva, L., Harding, I., Johnson, K., Kezina, T., Kodrul, T., Lu, J.S., Markevich, V., Nishida, H., Okada, H., Park, S.O., Sun, C.L., Xiong, X.Z., Xing, Y.L., Zhou, Z.L., 2002. In search of the Cretaceous-Tertiary Boundary in Heilongjiang River Area of China. Journal of Geoscientific Research in Northeast Asia 5 (2), 105e113. Sun, G., Akhmetiev, M.A., Golovneva, L., Bugdaeva, E., Quan, C., Kodrul, T., Nishida, H., Sun, Y., Sun, C., Johnson, K., Dilcher, D., 2007. Late Cretaceous Plants from Jiayin along Heilongjiang River, Northeast China. CFS Courier Forschungsinstitut Senckenberg 258, 75e83. Sun, G., Akhmetiev, M., Markevich, V., Ashraf, A.R., Bugdaeva, E., Godefroit, P., Bolotsky, Yu, Dong, Z.M., Golovneva, L., Yang, H.X., Sun, C.L., Sun, Y.W., Quan, C., Kodrul, T., Kezina, T., Johnson, K., Nishida, H., Dilcher, D.L., Harding, I., Chen, Y.J.,
G. Sun et al. / Cretaceous Research 67 (2016) 8e15 2011. Late Cretaceous biota and Cretaceous-Paleogene (K-Pg) boundary in Jiayin of Heilongjiang, China. Global Geology 14 (3), 115e143. Sun, G., Dong, Z.M., Akhmetiev, M., Markevich, V., Ashraf, A.R., Godefroit, P., Dilcher, D.L., Sun, C.L., Sun, Y.W., Quan, C., Golovneva, L., Bugdaeva, E., Bolotsky, Yu, Suzuki, S., Kodrul, T., Nishida, H., Kezina, T., Harding, I., Yang, H.X., Ge, W.C., Chen, Y.J., Yang, T., 2014. Late Cretaceous-Paleocene Biota and the K-Pg Boundary from Jiayin of Heilongjiang, China with Discussion on the Extinction of Dinosaurs. Shanghai Sci. Techn. Educ. Publishing House, Shanghai.
15
Suzuki, S., Ashraf, A.R., Okada, H., 2004. Sedimentary facies of Maastrichtian to Danian deposits in Amur River area, Russian Far East. Journal of Geoscientific Research in Northeast Asia 7 (2), 149e155. Wan, X., Zhao, J., Scott, R.W., Wang, P., Feng, Z., Huang, Q., Xi, D., 2013. Late Cretaceous stratigraphy, Songliao Basin, NE China: SK1 cores. Palaeogeography, Palaeoclimatology, Palaeoecology 385, 31e43. Zhang, Z.C., 1983. The Upper Cretaceous fossil plants from Jiayin Region, Northern Heilongjiang. Professional Papers of Stratigraphy and Palaeonology 11, 111e132.