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    2021,60(3):347-356, DOI: 10.19800/j.cnki.aps.2020050
    Abstract:
    Trace fossils record the behavioral characteristics of ancient organisms, and their preservations reflect the intimate interaction between organisms’ ethology, habitable substrates, and their living environments. In particular, soft-bodied organisms usually are difficult to be preserved in the fossil records, but their behaviors can be preserved as trace fossils. Thus, trace fossils are pivotal in reconstructing palaeoenvironmental and palaeoecological interpretations,deciphering the early evolution of life and the infaunal responses to environmental extremes during mass extinctions. This paper focuses on the advancement of the above mentioned ichnological research topics during the past ten years, and puts forward potential directions in future ichnological studies.
    2021,60(3):357-375, DOI: 10.19800/j.cnki.aps.2020026
    Abstract:
    The Ordovician in Yunkai area of western Guangdong Province mainly consists of sandstone, pelitic siltstone, silty mudstone and pebbly sandstone, and mudstone with intercalated carbonate rock lenses and conglomerates. The Ordovician includes the Lower Ordovician Luohong Formation and Luodong Formation, Middle Ordovician Dongchong Formation, and Upper Ordovician Lanweng Formation. Fossil bivalves, including the new taxa described in this paper, were collected from an about 2-meter-thick bed of gray to grayish yellow silty mudstone and pelitic siltstone of the upper part of the Dongchong Formation. The collection includes about one thousand bivalve specimens, which represent more than 22 species of 16 and several unnamed genera and may a possible new taxon. We report a group of unique bivalves including two new species of Yunannia gen. nov. of a new family Yunanniidae Zhang et Niu and a new superfamily Yunannioidea Zhang et Niu. This group demonstrate combined features normally attributed to different bivalve taxa. A small number of trilobites, including Nileus sp., Lonchobasilicus sp., Calymenesun tingi Sun, Calymenesun sp., Asaphopsis? sp., and brachiopods, including Paralenorthis sp., Aegira sp., Leptellina sp., Obolus? sp., Strophomena sp. and Nicolella sp., cooccur with the bivalves and indicate the Middle Ordovician age. SYSTEMATIC PALEONTOLOGYClass Bivalvia Linnaeus, 1758 in 1758–1759 Subclass Autobranchia Grobben, 1849 Infraclass Pteriomorphia Beurlen, 1944 Cohort Uncertain Superfamily Yunannioidea Zhang et Niu superfam. nov. Description Shell small, mytiliform, umbos anterior to terminal; strong inequilateral; buyssal sinus faint; the area beneath and anterior umbo edentulous; posterior to umbo a row of discrete chevron taxodont teeth; large anterior adductor muscle scar located in the umbonal angle and occupies the large and wide umbonal septum together with the anterior pedo-byssal retractors; posterior muscle scar unknown; external ligament, opisthodetic, submarginal; ligamental area narrow with 2-ranks of ligamental grooves and ridges, which are gently arched and extended continuously away from the dorsal margin; shell surface with faint comarginal growth lines. Remarks The Yunannioidea, a new superfamily of pteriomorphians is established based on the genus Yunannia proposed in the present paper. The Yunannia, the sole genus of the new superfamily Yunannioidea, is characterized by mytiliform outline, one posterior row of chevroned teeth, the large anterior adductor muscle scar located in the umbonal angle and inserted on the umbonal septum together with the anterior pedo-byssal retractor, and the arched two ranks of ligamental grooves and ridges which extend continuously away from dorsal margin. On the basis of features such as mytiliform, the musculature, and ligament, the Yunannioidea may be placed into the Cohort Mytilomorphi!. However, the genus Yunannia has only one row of posterior chevroned teeth. Together with its unusual hinge dentition, the new superfamily can be distinctly distinguished from other members of the same cohort. Meanwhile, features including the taxodont dentiotion and the two ranks of ligament indicate that Yunannia is likely in connection with Subcohort Ostreioni. Hence, the position of Yunannia at cohort level is undetermined. The genus Yunnania most possibly represents a new order of the infraclass Pteriomorphia. Family Yunannidae Zhang et Niu fam. nov. urn:lsid:zoobank.org:act:8A609836-4A82-4C6A-97B1-18168E761 891 Type genus Yunannia Zhang et Niu Yunannidae is the sole family of the new superfamily Yunannioidea. Distribution Middle Ordovician, Guangdong, China. Genus Yunannia Zhang et Niu gen. nov. urn:lsid:zoobank.org:act:B09DAFBA-A54D-4621-8FCD-07D8882 A6584 Type species Yunannia gankengensis Zhang et Niu gen. et sp. nov. Diagnosis Shell mytiliform, umbos anterior to terminal, with a row of posterior, discrete chevron taxodont teeth; anterior adductor muscle scar large and pedo-byssal retractor inserted on umbonal septum; ligament external and opisthodetic, extending continuously away from dorsal margin. Description The shell is small with height less than 21 mm. The shell shape is strongly inequilateral, mytiliform or narrow ovate with height longer than length. The umbos is anterior to terminal, projected and slightly incurved. Anterior lobe is absent. The dorsal-posterior margins are merged and widely arched. The anterior flange is thickened. The umbnal cavity is large and deep, separated by a lunate inner septum. The anterior adductor muscle scar is large and elliptical, located in the umbonalangle, and inserted on the umbanl septum together with the posteriorly extended pedo-byssal retractor. The growth line of anterior adductor muscle scar is present in one specimen. The anterior end of the anterior adductor scar is acuminate, likely marking the position of the pedal protractor but is obviously merged with the anterior adductor. The posterior adductor and posterior pedal retractor are unknown. The holotype, a left valve, bears about 20 teeth and sockets, while each half of a paratype bears about 8–15 teeth. The area anterior to and beneath umbo is edentulous. All teeth are discrete and chevroned with concavities towards distal end. The anterior two or three teeth are small and the rest become gradually larger posteriorly, achieving the maximum size about midway along the row of teeth. The teeth diminish gradually in size toward the posterior end of hinge plate. The ligament is external and opisthodetic, submarginal, sub-parallel to the gently arched dorsal-posterior shell margin. The ligamental area is narrow and extends posteriorly to about 3/4–4/5 height of shell, with one rather coarse ligamental ridge and two grooves above and below it (as the first-rank of ligament), while the weak and faint ligamental ridges and grooves (as the second-rank of ligament) within the first-rank ligamental grooves and ridge. Because of the number of first-rank ligamental groove-ridge couplets, it is likely the preduplivincular ligament. However, if the second-rank of ligament is also considered, the total number of ligamnental groove-rige couplets is more than two or three. Hence, it is likely the duplivincular ligament, rather than the preduplivincular ligament. In addition, the arched shape of ligamental area is similar to the simple arched ligament. The holotype specimen shows faint growth lines on the inner surface of shell wall. Etymology Yunan, a geographic name of a county in Guangdong Province. Remarks This genus is the sole representative of Yunannioidea superfam. nov. It is characterized by features such as the mytiliform shell having a posterior row of chevroned teeth, and the arched two ranks of ligamental groove-ridge couplets extending continuously away from the dorsal margin. The large anterior adductor located in the umbonal angle and inserted on the umbanl septum together with anterior pedo-byssal retractor. In addition, the large and wide umbonal septum is another distinguishing feature of Yunannia. The new genus combines some main features normally attributed to different bivalve taxa. Its dentition of taxodont teeth is similar to the Paleotaxodonta. The new genus and Ambonychioidea of Pteriomorphia share some features, including the mytiliform shape, terminal umbos and byssal sinus. Both the new genus Yunannia and cyrtodontoids have the same characteristic of sub-umbonaledentulous area. The present new genus and Dreissenoidea of Heteroconcha have common characters such as the anterior muscle scar inserted on umbonal septum, the submarginal, long, extended arched ligament. With the combination of features listed above, the new genus clearly distinguishes itself from all other genera in those taxa. Age and distribution Middle Ordovician; Guangdong, China. Yunannia gankengensis Zhang et Niu gen. et sp. nov. urn:lsid:zoobank.org:act:67E7B718-0211-4EBB-ADA9-898045A3 8637 (Figs. 3–5) Materials 8 specimens of internal moulds including 5 left valves and 3 right valves. Holotype: No. Ng4032, Paratypes: Ng4033, Ng4030, Ng4031, Ng1041. Diagnosis Height/length(width) ratio less than 1.5; ventral part of shell expanded and swollen. Description The shell is small, mytiliform, strongly inequilateral with height less than 20 mm. The height is longer than the length (width) with height/length(width) ratio less than 1.5. The umbos is terminal, projected and slightly incurved. The anterior lobe is absent. A faint byssal sinus is present at the upper part of anterior margin. The dorsal-posterior margins are merged and widely arched. A long and thickened anterior flange is present behind the anterior margin. A large umbnal cavity is separated by a lunate umbonal septum. The elliptical and large anterior adductor muscle scar is located in the umbonal angle, together with anterior pedo-byssal retractor, occupying the umbonal septum. The anterior adductor muscle scar being covered by growth line is showed in one paratype specimen (No. Ng1041). The anterior end of the anterior adductor scar is acuminate, which likely marks the position of the pedal protractor, but is obviously merged with the anterior adductor (as to otherwise indistinguishable). The posterior adductor and posterior pedal retractor are unknown. The area anterior to and beneath the umbo is edentulous. Posterior to the umbo there is a row of teeth consisting of 13–20 discrete and chevroned teeth with concavities towards the distal end. The anterior and posterior two or three teeth are small with the maximum size at the midway along the tooth row. The ligament is external and opisthodetic, submarginal, sub-parallel to the gently arched dorsal-posterior shell margin. The ligamenal area is narrow, extending posteriorly away from dorsal margin to about 4/5 height of the shell with one rather coarse ligamental ridge and two grooves laid above and below it (as the first rank of ligament), which are subdivided by the weak and faint (as the second rank) ligamental ridges and grooves. Because of the number of the first rank ligamental groove and ridge couplets, it is likely the preduplivincular ligament. However, if the second-rankof ligament is also considered, the total number of ligamnental groove-rige couplets is more than 2–3. Hence, it is likely the duplivincular ligament, rather than the preduplivincular ligament. Faint growth lines are present on the shell surface. Measurement Holotype: No. Ng4032: height 17.5 mm, length 13, H/L = 1.35. Etymology Gankeng, a geographic name of Guangdong. Comparison The present new species evidently differs from Yunannia yunkaiensis gen. et sp. nov. in having mytiliform shape, shell becoming gradually wider towards ventral side, with the maximum width near the ventral part of the shell, and a height/length ration less than 1.5. The latter species has a narrow and narrow ovate shape and a height/length ration about 2. Occurrence Gankeng Village, Yunan County, Guangdong Province; Dongchong Formation, Middle Ordovician. Yunannia yunkaiensis Zhang et Niu gen. et sp. nov. urn:lsid:zoobank.org:act:BE7BF3A3-3F07-4049-88F3-2EE989D4 E914 (Fig. 6) Materials 3 internal moulds of left valve. Holotype: No. Ng4035, Paratypes: Ng074, Ng4034. Diagnosis Shape narrow ovate and H/L ratio about 2.0. Description The shell is small, narrow ovate, strongly in-equilateral, 16.5–21 mm high. The height is much longer than the length with a H/L ratio of 2.0. The umbos is projected and slightly incurved. The anterior lobe is absent. The dorsal-posterior margins are merged and gently arched. The thickened anterior flange is relatively narrow. The umbonal cavity is separated by lunate, relatively narrow umbonal septum. The large and elliptical anterior adductor muscle scar is located in the umbonal angle, and together with the pedo-byssal retractor, inserted on umbanl septum. The anterior end of the anterior adductor scar is deeply inserted and becomes shallow poster-ventrally. The posterior adductor and posterior pedal retractor are unknown. The area anterior to and beneath umbo is edentulous with a posterior row of hinge tooth consisting of more than 8 to 13 discrete and chevroned teeth with concavities towards the distal end. The ligament is external and epithetic, submarginal. The ligamental area is narrow, sub-parallel to the gently arched dorsal-posterior shell margin, extending posteriorly away from dorsal margin to about 3/4 height of shell, and with one rather coarse ligamental ridge and two grooves above and below it (as the first rank of ligament). The four weak and faint ligamental groove-ridge couplets (as the second rank of ligament) extend about 5 mm in length in the dorsal side of the groove of the first rank ligament. Surface ornaments of the shell are unknown. Measurement Holotype: No. Ng4035; height 21 mm, length 10 mm, ratio H/L = 2.0. Etymology Yunkai, a regional geographic name in Guangdong Province. Comparison The present new species is distinguished from the genotype, Yunannia gankenensis (gen. et sp. nov) by the narrow ovate shape with a H/L ratio of 2, and the slightly incurved umbo. In contrast to the latter species’ mytiliform shape and a H/L ratio less than 1.5. On the respect of shell shape, the present species is more or less similar to Mytilarca chenmungensis (Conrad) (Pojeta, 1966, pl. 37, figs. 8–18; pl. 38, figs. 1–5, 10), but it differs from the latter species by having a subumbonal edentulous area, a posterior row of taxodont teeth, a large anterior adductor muscle scar, and large anterior pedo-byssal retractors laid on unmbonal septum. Occurrence Gankeng Village, Yunan County, Guangdong Province, Dongchong Formation, Middle Ordovician.
    2021,60(3):376-400, DOI: 10.19800/j.cnki.aps.2020036
    Abstract:
    The Renyi Section is a newly discovered section in the vicinity of Renyi Town, Hezhou City of Guangxi, in which a continuous marine sedimentary succession of the Middle and Upper Devonian is well developed and out-cropped. The succession yields abundant benthic and pelagic fossils. This paper presents a preliminary research resulton the conodonts and brachiopods from the middle part of the Middle-Upper Devonian Baqi Formation (ca. 80 m thick) at this section. Ten species (or subspecies) of three genera of conodonts are recognized from the studied interval, including Polygnathus alatus, P. cf. collieri, P. cristatus, P. dubius, P. dengleri, P. dengleri sagitta, P. webbi, P. xylus, Klapperina disparalvea and Schmidtognathus wittekindti. Seventeen species of 16 genera of brachiopods are also reported herein, including Schizophoria sp., Gypidula sp., productoid gen. et sp. indet., Leiorhynchus kwangsiensis, Coeloterorhynchus sp., Hypothyridina sp., Uncinulus? sp., Fitzroyella sp., “Ypsilorhychus” subellipticus, Desquamatia sp., Spinatrypina douvillii, Spinatrypina sp., Emanuella sp., Mucrospirifer sp., Undispiriferoides tianqipuensis, Cryptonella? sp. and Oligothyrina? sp. According to the distribution of the conodonts, three conodont zones (S. hermanni, P. cristatus and K. disparilis zones) have been recognized from the studied interval, suggesting an age of late Givetian of the Middle Devonian. The brachiopods were mainly collected from two fossiliferous layers near the base and top of the studied interval, representing two different brachiopod assemblages. The brachiopod fauna from the lower fossiliferous layer (ca. 20 cm thick, S. hermanni Zone) is relatively monotonous in composition, mainly consisting of L. kwangsiensis. This finding verifies the Middle Devonian occurrence of the genus Leiorhynchus in South China. The upper fossiliferous layer (ca. 3 m, upper K. disparilis subzone) yields a diverse brachiopod fauna, including at least 15 genera and displaying the highest diversity of brachiopods ever recorded in a single fossiliferous bed from the upper Givetian of South China.
    2021,60(3):401-414, DOI: 10.19800/j.cnki.aps.2021020
    Abstract:
    The genus Mesypochrysa Martynov, 1927 (Neuroptera: Chrysopidae: Limaiinae) is the oldest genus in the subfamily Limaiinae. The species of this genus can be identified by the numbers of basal subcostal crossveins (0–2), the branches of Rs (7–26), m-cu crossveins (2, 3), the pectinate branches of CuA+MP (4–7), and the pattern of forking of 1A and 2A (forked or not) in the forewing. Mesypochrysa intermedia Panfilov, 1980 is characterized by the presence of one basal subcostal crossvein in the forewing; Rs with about 14 branches; the presence of 1m-cu crossvein; CuA+MP with 6 distal pectinate branches; and 1A, 2A not being forked. Many specimens of this species have been found, but most of them are preserved with only forewings, except one specimen of Mesypochrysa cf. intermedia (NIGP 161886) which has an incomplete hind wing. A new specimen with nearly complete forewings and hind wings of this species was collected from the Middle Jurassic Jiulongshan Formation in Daohugou Village, Ningcheng County, Chifeng City, Inner Mongolia, China. Based on observation of this specimen, we revise the diagnosis of Mesypochrysa intermedia. The recorded specimens of M. intermedia, the differences between the genus Mesypochrysa and other genera of the Mesozoic, as well as the characteristics of each species of Mesypochrysa are also discussed in detail.
    2021,60(3):415-428, DOI: 10.19800/j.cnki.aps.2021002
    Abstract:
    The western Liaoning region is known as one of the most significant fossil wood localities in China with diverse and abundant Cretaceous petrified woods. The Early Cretaceous petrified wood bearing horizons, including the Yixian, Jiufotang, Shahai and Fuxin formations, are relatively continuous. Among them, the most abundant wood fossils arefound from the Shahai Formation. Though some studies have been carried out previously, the composition of the fossil wood flora of the Shahai Formation remains poorly understood. In this paper, we report some well-preserved fossil woods from the Shahai Formation in Shidonggou village of Yixian County, Liaoning Province. Three species referable to two genera are identified, i.e., Phyllocladoxylon cf. eboracense (Holden) Kr?usel, Xenoxylon conchylianum Fliche and X. watarianum Nishida and Nishida. Among them, Phyllocladoxylon cf. eboracense is anatomically characterized by having distinct growth rings, uniseriate distant radial pits, and one large oopore per cross-field. Xenoxylon watarianum is featured by the presence of distinct growth rings, typical xenoxylean radial pitting, window-like cross-field pits, and a low ray height of 1?10 (mostly 2?5) cells. Then for X. conchylianum, it also bears xenoxylean radial pitting and window-like cross-field pits, but with a higher ray height of 1?21 (mostly 3?10) cells. The current new finding contributes to further understanding of the fossil wood diversity of the Shahai Formation and provides new fossil evidence for revealing the forest composition in western Liaoning during the late Early Cretaceous. The diversity of the Early Cretaceous wood fossils in western Liaoning is summarized. From the perspective of the wood fossils, it is inferred that the forest vegetation may have undergone some degree of changes during the transition of the middle to late Early Cretaceous in western Liaoning. In addition, this paper analyzes the species-level diversity of the Jurassic and Cretaceous Xenoxylon in western Liaoning area, and proposes that this genus was a dominant group all through the late Mesozoic. However, there is a difference in species-level composition between the Jurassic and Cretaceous intervals.
    2021,60(3):429-438, DOI: 10.19800/j.cnki.aps.2021045
    Abstract:
    Abundant fossil records indicate that the genus Osmunda L. was widely distributed in the Northern Hemisphere during the Mesozoic and Cenozoic. Here, a new species of Osmunda, namely Osmunda zhangpuensis Z. X. Wang and B N. Sun, sp. nov., is described based on well-preserved sterile pinnules from the middle Miocene Fotan Group in Fujian, Southeast China. The pinnules of the new species are linear-lanceolate with serrate margins and pin-nate venation. Of extant Osmunda species, O. zhangpuensis sp. nov. most closely resembles Osmunda banksiifolia. Thediscovery of the new species suggests that the Osmunda existed in this region during the middle Miocene. Moreover, the presence of O. zhangpuensis sp. nov., together with the epiphyllous fungi on many leaf megafossils of Dipterocarpaceae, Moraceae, Fabaceae, Urticaceae, Calophyllaceae, Euphorbiaceae, and Lauraceae, suggests that the paleoclimate during the middle Miocene in Fujian, China was warm and humid.
    2021,60(3):439-454, DOI: 10.19800/j.cnki.aps.2020065
    Abstract:
    This paper reports fossil mammutid proboscideans from the late Miocene of the Xiaohe Formation, Yuanmou Basin, Yunnan Province. They were recovered from three localities: Zhupeng, Huiwoqing, and Leilao, and belong to two taxa: Pliomastodon? zhupengensis comb. nov. and Mammut lufengense. SYSTEMATIC PALEONTOLOGYOrder Proboscidea Illiger, 1811 Family Mammutidae Hay, 1922 Genus Pliomastodon Osborn, 1926 Pliomastodon? zhupengensis (Zhang et al., 1991 in Ji and Zhang, 1997, comb. nov.) Type specimen YICRA YV0787, left M3, see Ji and Zhang (pl. 28, fig. 1). Type locality Zhupeng. Diagnosis Pliomastodon? with moderately elongated symphysis and lower tusks, lacking the posterior mental foramen. Upper tusks straight, dorsally bent and enamel-less. A low degree of cheek teeth zygodonty: relative to Mammut, subdivision of lophs/lophids not pronounced, thick pretrite crescentoids with the possibility of presence of pretrite central conules, interlophs/interlophids half stuffed by pretrite crescentoids and/or central conules. Referred material MCY C1134ZA94, mandible, with associated palate and right upper tusk, from Huwoqing; YMM 297, incomplete mandible, from Leilao; YICRA YV768 and YV784, two left M3s, as well as YMM 3121X081, right m3, from Zhupeng (Figs. 3, 4). Age: Late Miocene, ~8.2?7.2 Ma (Dong and Qi, 2013). Description and comparison The mandibular possesses a straight ventral border. The mandibular symphysis is narrow and moderately elongated with a deep trough. It tips slightly downward. The corpus is strong and the ramus is low. The upper tusk is straight and long. It is slightly dorsally bent without an enamel-band. The lower tusks are short rod-like. They are closely apposed with a nearly round cross-section. The above features are very similar to those of Mammut obliquelophus(Tobien, 1976). The M3 is tetralophodont. The lophs are blunter than those of Mammut. The interlophs are narrow. The pretrite half lophs possess thicker anterior and posterior crescentoids than those of Mammut. Occasionally the pretrite central conules are present. In lateral view from the pretrite side, the crescentoids and/or central conules reach at least half of the interlophs. The posttrite half lophs are less subdivided than those of Mammut. The posttrite main cusp and mesoconelets are generally well-separated. The zygodont crests are blunt. The m2 is trilophodont, and the m3 is tetra- or pentalophodont. The interlophids are wider than the M3, and the posterior pretrite central conules are usually present. Lophids are obliquely arranged with a somewhat chevron in the distal lophids. In some cases, the second pretrite and posttrite half lophids are alternatively positioned. The other features are similar to those of the M3, and differs from the m3 of Mammut in the same way as those of its M3. Pliomastodon? zhupengensis succeeded the low degree of zygodonty from Miomastodon gobiensis of the Middle Miocene of northern China (Wang et al., 2020). Like the other Late Miocene mammutids with high zygodonty, i.e., Mammut and Pliomatodon (Tobien, 1976, Osborn, 1936), Pliomastodon? zhupengensis curved the upper tusks upward and lost the enamel band. The molar morphology of Pliomastodon? zhupengensis displays few differences from Sinamstodon praeintermedius (Figs. 6-A–6-D), except the lower tooth crown and fewer lophids of the m3. It is the potential direct ancestor of the latter, which was recovered from the Shuitangba locality, Zhaotong Basin in the vicinity, ~6.5?6.0 Ma (Wang et al., 2016). Tobien et al. (1986) believed that Sinomastodon is morphologically and phylogenetically close to the American brevirostrinegomphotheres, especially the Notiomastodon, and migrated back from American. This opinion is questioned here: 1, the earliest Notiomastodon occurred at ~2.5 Ma in South America (Mothé et al., 2016), which is far later than the occurrence of Sinomastodon; 2, Sinomastodon sensu Tobien et al. actually comprises two morphological types, a more zygodont-like type (Mastodon intermedius, originally attributed to Mammutidae) from the Pliocene, and a more bunodont-like type from the Pleistocene (originally attributed to Gomphotherium); 3, collagen sequence of Notiomastodon are closer to that of Mammut than of the true elephantids (derived from the gomphotheres) (Buckley et al., 2019), which reveals that the evolution of Gomphotheriidae and Mammutidae was deeply involved rather than simply detached. Sinomastodon is more likely a mammutid. Genus Mammut Blumenbach, 1799 Mammut lufengense (Zhang, 1982) Type specimen YICRA YV0131, left m3, see Zhang (pl. 1, fig. 1). Type locality Shihuiba, Lufeng, Yunnan Province. Referred material YICRA XDYV001, right M2, YICRA XDYV002, anterior two lophs of right M3, YICRA XDYV003, left m2, YICRA XDYV004, left m3, unearthed at the same time from Leilao, Yuanmou, Yunnan Province (Fig. 5). Age: Late Miocene, 6.9?6.2 Ma (Dong and Qi, 2013). Description and comparison The deeply worn M2 and m2 are trilophodont. The M3 (keeping the anterior two lophs) possesses sharp lophs. The posttrite half lophs are subdivided into small conelets with an obscure separation between the main and mesoconelets. The pretrite mesoconelets are short crest-like, and the pretrite crescentoids are thin and sharp, reaching the bottom of the interlophs in side views. The zygodont crest are thin and clear. The m3 is tetralophodont. The lophids are highly mesiodistally compressed with wide interlophids. The posttrite half lophids are moderately to highly subdivided, and the separation between the main and mesoconelets is clearer than that of the M3. The pretrite crescentoids are somewhat thicker than those of the M3, and reach the 1/3 of the interlophid height. Chevron is developed on the posterior two lophids. Generally, the tooth morphology of Mammut lufenense shows little difference from the contemporary Eurasian species, Mammut obliquelophus (= M. preatypicum). Unfortunately, the condition of the upper and lower tusks, and mandibular symphysis is unknown. Here we temporarily keep the species name, ‘lufengensis’, and transferred it to Mammut, as a highly zygodont mammutid representative of southern China during this age. Besides from Yuanmou, Mammut lufenense was also recovered from the adjacent Lufeng (6.9?6.2 Ma) (Dong and Qi, 2013) and Zhaotong (6.5?6.0 Ma) (Ji et al., 2013), Yunnan Province (Figs. 6-E?6-H). It can be inferred that two types of Mammutidae, the less zygodont Pliomastodon?, and the high zygodont Mammut, coexisted in a long period during the late Miocene of southern China.
    2021,60(3):455-470, DOI: 10.19800/j.cnki.aps.2020062
    Abstract:
    Based on pollen analysis of 17 samples of surface lake sediments from Xuanwu Lake and Qianhu Lake from the foothill of the Purple Moutain in Nanjing, pollen assemblages are established to reveal the relationship between surface pollen flora as well as modern vegetation and to provide a modern reference for Quaternary pollen analysis of lacustrine sediments. The results show that apart from abundant human-induced woody taxa, Pinus and Quercus are the dominant elements in the pollen assemblages, and other important pollen taxa such as Liquidambar, Castanea?Castanopsis?Lithocarpus, Anacardiaceae occur frequently. The pollen spectrum generally indicates the coniferous and mixed evergreen-deciduous broad-leaved forest in the surrounding mountains and hills, consistent with the present vegetation of northern subtropical forest. In addition, herbs such as Poaceae and Artemisia and lake wetland plants such as Hydrocharis and Cyepraceae are abundant. The dominant types of trees from different samples in Xuanwu Lake and Qianhu Lake are highly consistent; each sample is ather stable in contents; and both are little affected by sampling location. By comparing with existing modern pollen data of topsoil in forests in Nanjing area, we found that the pollen assemblages of the surface lake sediments are characterized by stable percentages of dominant taxa with little influences of local habitats, suggesting their advantages of reflecting regional vegetation. In order to improve the representativeness and reliability of the relationship between regional vegetation and pollen assemblages, this paper highly suggests that surface lake sediments should be preferred to use for pollen analysis in Quaternary pollen interpretation. This paper yields new data and provides necessary modern basis for Quaternary palynological investigation in terms of pollen-vegetation relationship in the lower reaches of the Yangtze River, especially in Nanjing area.
    2021,60(3):471-482, DOI: 10.19800/j.cnki.aps.2020064
    Abstract:
    The Tianshan Mountains, one of the famous mountain ranges in northwest China, forms a complete geographic zone and divides Xinjiang province into two different natural geographic units: southern and northern Xinjiang. These two units display distinct vertical gradient distributions of climate, soil and vegetation types which impact on pollen transportation, dispersion, preservation and deposition. Based upon pollen assemblages of 50 modern pollen samples and the data of vegetation plots, both of which were collected from the northern slope of western Tianshan Mountains, we analyzed the relationship between vegetation and surface pollen assemblages and compared different pollen assemblages of the Tianshan Mountains. (1) We divide the pollen spectra into five pollen assemblage zones, i.e., mountain desert, steppe, forest, subalpine meadow, and alpine cushion, according to major vegetation types of the north slope of the western Tianshan Mountains. (2) When the percentage of Picea pollen is 25%–30%, the sample can be considered coming from the Picea forest. The dominance of Picea-Artemisia-Chenopodiaceae-Apiaceae assemblage indicates the existence of a forest vegetation. The subalpine meadow and steppe are dominated by Artemisia-Chenopodiaceae-Poaceae-Picea-Ephedra assemblage. High percentage of Chenopodiaceae-Artemisia pollen indicates mountain desert and alpine cushion vegetation. Picea pollen is representative, and its proportion in a sample is consistent with the distribution of modern vegetation, but is significantly affected by airflow. The distribution of Ephedra pollen is also affected by airflow, and its percentage cannot be used to infer whether the vegetation exists around the sample site or not. Artemisia and Chenopodiaceae pollen are super representative, but they are only of regional ecological significance, while Poaceae pollen shows low representativeness due to its low yield. (3) The vertical pollen spectra are the most complicated in the north slope of western Tianshan.
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    Abstract:
    The Ordovician in Yunkai area of western Guangdong Province mainly consists of sandstone, pelitic siltstone, silty mudstone and pebbly sandstone, and mudstone with intercalated carbonate rock lenses and conglomerates. The Ordovician includes the Lower Ordovician Luohong Formation and Luodong Formation, Middle Ordovician Dongchong Formation, and Upper Ordovician Lanweng Formation. Fossil bivalves, including the new taxa described in this paper, were collected from an about 2-meter-thick bed of gray to grayish yellow silty mudstone and pelitic siltstone of the upper part of the Dongchong Formation. The collection includes about one thousand bivalve specimens, which represent more than 22 species of 16 and several unnamed genera and may a possible new taxon. We report a group of unique bivalves including two new species of Yunannia gen. nov. of a new family Yunanniidae Zhang et Niu and a new superfamily Yunannioidea Zhang et Niu. This group demonstrate combined features normally attributed to different bivalve taxa. A small number of trilobites, including Nileus sp., Lonchobasilicus sp., Calymenesun tingi Sun, Calymenesun sp., Asaphopsis? sp., and brachiopods, including Paralenorthis sp., Aegira sp., Leptellina sp., Obolus? sp., Strophomena sp. and Nicolella sp., cooccur with the bivalves and indicate the Middle Ordovician age. SYSTEMATIC PALEONTOLOGYClass Bivalvia Linnaeus, 1758 in 1758–1759 Subclass Autobranchia Grobben, 1849 Infraclass Pteriomorphia Beurlen, 1944 Cohort Uncertain Superfamily Yunannioidea Zhang et Niu superfam. nov. Description Shell small, mytiliform, umbos anterior to terminal; strong inequilateral; buyssal sinus faint; the area beneath and anterior umbo edentulous; posterior to umbo a row of discrete chevron taxodont teeth; large anterior adductor muscle scar located in the umbonal angle and occupies the large and wide umbonal septum together with the anterior pedo-byssal retractors; posterior muscle scar unknown; external ligament, opisthodetic, submarginal; ligamental area narrow with 2-ranks of ligamental grooves and ridges, which are gently arched and extended continuously away from the dorsal margin; shell surface with faint comarginal growth lines. Remarks The Yunannioidea, a new superfamily of pteriomorphians is established based on the genus Yunannia proposed in the present paper. The Yunannia, the sole genus of the new superfamily Yunannioidea, is characterized by mytiliform outline, one posterior row of chevroned teeth, the large anterior adductor muscle scar located in the umbonal angle and inserted on the umbonal septum together with the anterior pedo-byssal retractor, and the arched two ranks of ligamental grooves and ridges which extend continuously away from dorsal margin. On the basis of features such as mytiliform, the musculature, and ligament, the Yunannioidea may be placed into the Cohort Mytilomorphi!. However, the genus Yunannia has only one row of posterior chevroned teeth. Together with its unusual hinge dentition, the new superfamily can be distinctly distinguished from other members of the same cohort. Meanwhile, features including the taxodont dentiotion and the two ranks of ligament indicate that Yunannia is likely in connection with Subcohort Ostreioni. Hence, the position of Yunannia at cohort level is undetermined. The genus Yunnania most possibly represents a new order of the infraclass Pteriomorphia. Family Yunannidae Zhang et Niu fam. nov. urn:lsid:zoobank.org:act:8A609836-4A82-4C6A-97B1-18168E761 891 Type genus Yunannia Zhang et Niu Yunannidae is the sole family of the new superfamily Yunannioidea. Distribution Middle Ordovician, Guangdong, China. Genus Yunannia Zhang et Niu gen. nov. urn:lsid:zoobank.org:act:B09DAFBA-A54D-4621-8FCD-07D8882 A6584 Type species Yunannia gankengensis Zhang et Niu gen. et sp. nov. Diagnosis Shell mytiliform, umbos anterior to terminal, with a row of posterior, discrete chevron taxodont teeth; anterior adductor muscle scar large and pedo-byssal retractor inserted on umbonal septum; ligament external and opisthodetic, extending continuously away from dorsal margin. Description The shell is small with height less than 21 mm. The shell shape is strongly inequilateral, mytiliform or narrow ovate with height longer than length. The umbos is anterior to terminal, projected and slightly incurved. Anterior lobe is absent. The dorsal-posterior margins are merged and widely arched. The anterior flange is thickened. The umbnal cavity is large and deep, separated by a lunate inner septum. The anterior adductor muscle scar is large and elliptical, located in the umbonalangle, and inserted on the umbanl septum together with the posteriorly extended pedo-byssal retractor. The growth line of anterior adductor muscle scar is present in one specimen. The anterior end of the anterior adductor scar is acuminate, likely marking the position of the pedal protractor but is obviously merged with the anterior adductor. The posterior adductor and posterior pedal retractor are unknown. The holotype, a left valve, bears about 20 teeth and sockets, while each half of a paratype bears about 8–15 teeth. The area anterior to and beneath umbo is edentulous. All teeth are discrete and chevroned with concavities towards distal end. The anterior two or three teeth are small and the rest become gradually larger posteriorly, achieving the maximum size about midway along the row of teeth. The teeth diminish gradually in size toward the posterior end of hinge plate. The ligament is external and opisthodetic, submarginal, sub-parallel to the gently arched dorsal-posterior shell margin. The ligamental area is narrow and extends posteriorly to about 3/4–4/5 height of shell, with one rather coarse ligamental ridge and two grooves above and below it (as the first-rank of ligament), while the weak and faint ligamental ridges and grooves (as the second-rank of ligament) within the first-rank ligamental grooves and ridge. Because of the number of first-rank ligamental groove-ridge couplets, it is likely the preduplivincular ligament. However, if the second-rank of ligament is also considered, the total number of ligamnental groove-rige couplets is more than two or three. Hence, it is likely the duplivincular ligament, rather than the preduplivincular ligament. In addition, the arched shape of ligamental area is similar to the simple arched ligament. The holotype specimen shows faint growth lines on the inner surface of shell wall. Etymology Yunan, a geographic name of a county in Guangdong Province. Remarks This genus is the sole representative of Yunannioidea superfam. nov. It is characterized by features such as the mytiliform shell having a posterior row of chevroned teeth, and the arched two ranks of ligamental groove-ridge couplets extending continuously away from the dorsal margin. The large anterior adductor located in the umbonal angle and inserted on the umbanl septum together with anterior pedo-byssal retractor. In addition, the large and wide umbonal septum is another distinguishing feature of Yunannia. The new genus combines some main features normally attributed to different bivalve taxa. Its dentition of taxodont teeth is similar to the Paleotaxodonta. The new genus and Ambonychioidea of Pteriomorphia share some features, including the mytiliform shape, terminal umbos and byssal sinus. Both the new genus Yunannia and cyrtodontoids have the same characteristic of sub-umbonaledentulous area. The present new genus and Dreissenoidea of Heteroconcha have common characters such as the anterior muscle scar inserted on umbonal septum, the submarginal, long, extended arched ligament. With the combination of features listed above, the new genus clearly distinguishes itself from all other genera in those taxa. Age and distribution Middle Ordovician; Guangdong, China. Yunannia gankengensis Zhang et Niu gen. et sp. nov. urn:lsid:zoobank.org:act:67E7B718-0211-4EBB-ADA9-898045A3 8637 (Figs. 3–5) Materials 8 specimens of internal moulds including 5 left valves and 3 right valves. Holotype: No. Ng4032, Paratypes: Ng4033, Ng4030, Ng4031, Ng1041. Diagnosis Height/length(width) ratio less than 1.5; ventral part of shell expanded and swollen. Description The shell is small, mytiliform, strongly inequilateral with height less than 20 mm. The height is longer than the length (width) with height/length(width) ratio less than 1.5. The umbos is terminal, projected and slightly incurved. The anterior lobe is absent. A faint byssal sinus is present at the upper part of anterior margin. The dorsal-posterior margins are merged and widely arched. A long and thickened anterior flange is present behind the anterior margin. A large umbnal cavity is separated by a lunate umbonal septum. The elliptical and large anterior adductor muscle scar is located in the umbonal angle, together with anterior pedo-byssal retractor, occupying the umbonal septum. The anterior adductor muscle scar being covered by growth line is showed in one paratype specimen (No. Ng1041). The anterior end of the anterior adductor scar is acuminate, which likely marks the position of the pedal protractor, but is obviously merged with the anterior adductor (as to otherwise indistinguishable). The posterior adductor and posterior pedal retractor are unknown. The area anterior to and beneath the umbo is edentulous. Posterior to the umbo there is a row of teeth consisting of 13–20 discrete and chevroned teeth with concavities towards the distal end. The anterior and posterior two or three teeth are small with the maximum size at the midway along the tooth row. The ligament is external and opisthodetic, submarginal, sub-parallel to the gently arched dorsal-posterior shell margin. The ligamenal area is narrow, extending posteriorly away from dorsal margin to about 4/5 height of the shell with one rather coarse ligamental ridge and two grooves laid above and below it (as the first rank of ligament), which are subdivided by the weak and faint (as the second rank) ligamental ridges and grooves. Because of the number of the first rank ligamental groove and ridge couplets, it is likely the preduplivincular ligament. However, if the second-rankof ligament is also considered, the total number of ligamnental groove-rige couplets is more than 2–3. Hence, it is likely the duplivincular ligament, rather than the preduplivincular ligament. Faint growth lines are present on the shell surface. Measurement Holotype: No. Ng4032: height 17.5 mm, length 13, H/L = 1.35. Etymology Gankeng, a geographic name of Guangdong. Comparison The present new species evidently differs from Yunannia yunkaiensis gen. et sp. nov. in having mytiliform shape, shell becoming gradually wider towards ventral side, with the maximum width near the ventral part of the shell, and a height/length ration less than 1.5. The latter species has a narrow and narrow ovate shape and a height/length ration about 2. Occurrence Gankeng Village, Yunan County, Guangdong Province; Dongchong Formation, Middle Ordovician. Yunannia yunkaiensis Zhang et Niu gen. et sp. nov. urn:lsid:zoobank.org:act:BE7BF3A3-3F07-4049-88F3-2EE989D4 E914 (Fig. 6) Materials 3 internal moulds of left valve. Holotype: No. Ng4035, Paratypes: Ng074, Ng4034. Diagnosis Shape narrow ovate and H/L ratio about 2.0. Description The shell is small, narrow ovate, strongly in-equilateral, 16.5–21 mm high. The height is much longer than the length with a H/L ratio of 2.0. The umbos is projected and slightly incurved. The anterior lobe is absent. The dorsal-posterior margins are merged and gently arched. The thickened anterior flange is relatively narrow. The umbonal cavity is separated by lunate, relatively narrow umbonal septum. The large and elliptical anterior adductor muscle scar is located in the umbonal angle, and together with the pedo-byssal retractor, inserted on umbanl septum. The anterior end of the anterior adductor scar is deeply inserted and becomes shallow poster-ventrally. The posterior adductor and posterior pedal retractor are unknown. The area anterior to and beneath umbo is edentulous with a posterior row of hinge tooth consisting of more than 8 to 13 discrete and chevroned teeth with concavities towards the distal end. The ligament is external and epithetic, submarginal. The ligamental area is narrow, sub-parallel to the gently arched dorsal-posterior shell margin, extending posteriorly away from dorsal margin to about 3/4 height of shell, and with one rather coarse ligamental ridge and two grooves above and below it (as the first rank of ligament). The four weak and faint ligamental groove-ridge couplets (as the second rank of ligament) extend about 5 mm in length in the dorsal side of the groove of the first rank ligament. Surface ornaments of the shell are unknown. Measurement Holotype: No. Ng4035; height 21 mm, length 10 mm, ratio H/L = 2.0. Etymology Yunkai, a regional geographic name in Guangdong Province. Comparison The present new species is distinguished from the genotype, Yunannia gankenensis (gen. et sp. nov) by the narrow ovate shape with a H/L ratio of 2, and the slightly incurved umbo. In contrast to the latter species’ mytiliform shape and a H/L ratio less than 1.5. On the respect of shell shape, the present species is more or less similar to Mytilarca chenmungensis (Conrad) (Pojeta, 1966, pl. 37, figs. 8–18; pl. 38, figs. 1–5, 10), but it differs from the latter species by having a subumbonal edentulous area, a posterior row of taxodont teeth, a large anterior adductor muscle scar, and large anterior pedo-byssal retractors laid on unmbonal septum. Occurrence Gankeng Village, Yunan County, Guangdong Province, Dongchong Formation, Middle Ordovician.
    Abstract:
    Populus L. is an ecologically important tree genus in the Northern Hemisphere temperate forest. In this paper we summarize the Populus fossil records from the Paleogene and Neogene of the Tibetan Plateau with updated stratigraphic and chronological data. Fossil evidence shows that Populus first occurred in the plateau in the latest Eocene. The genus is well-documented in the southern and northern Tibetan Plateau in the Oligocene and Miocene, but lacking in the central plateau. Most of the fossil floras in the Tibetan Plateau containing Populus are temperate, deciduous and broadleaved, riparian vegetation, further confirming that the genus had favored a temperate and riparian environment in their early evolutionary history. Besides, the high diversity and prominent dominance of Populus in early Oligocene flora in the northern Tibetan Plateau suggests this region had played an important role in the early diversification stage of Populus.
    Abstract:
    The journey to understand the Cambrian explosion started with Creation, was subsequently succeeded by Darwinism, and became increasingly impacted by the theory of explosive evolution. The Cambrian explosion by nature is an explosion of animal body plans alongside episodic biomineralization, pulsed change of generic diversity, body size variation, and increase of ecosystem complexity. It is a polythetic event in natural history and manifested in many aspects. No simple, single cause can explain the entire phenomenon. Intrinsic and extrinsic causes were extensively discussed but they are merely prerequi-sites for the Cambrian explosion. Without the molecular evolution, there could be no Cambrian explosion. However, the de-velopmental system alone is insufficient to explain Cambrian explosion. Time-equivalent environmental changes were often considered as extrinsic causes, but the time coincidence is also insufficient to establish causality. Like any other evolutionary event, it is the ecology that makes the Cambrian explosion possible though ecological processes failed to cause a burst of new body plans in the subsequent evolutionary radiations. While the Cambrian explosion did take place under circumstances when the world oceans became habitable for various forms of animals, the developmental Gene Regulatory Networks (GRNs) were sufficiently complex for constructing complex forms, and resource supply was less restricted. It seems that opportunities were in every corner! Early metazoans shared seafloors with vendobionts for the last 20 million years of the Ediacaran, although their ecological relationships are less known. Metazoans followed the path of evolving organs and sys-tems, developing orderly repetition of body parts, and attempting possibilities, which enable the evolution of morphological, physiological, ecological variations and complexity. While vendobionts kept their less differentiated body designs, tis-sue-grade organization, and probably osmotic physiology. Consequently, Ediacarans died off at the end of their era for un-known reasons. Thereafter metazoans rapidly diversified and generated numbers of phylum-rank stem or crown lineages with different fates. The Cambrian explosion ultimately resulted in the critical transition from microbially-dominated ecosys-tems in the Precambrian to metazoan-dominated ecosystems in the Phanerozoic. However, the temporospatial pattern of eco-systems during the Cambrian explosion is poorly understood, largely because our current knowledge is biased in metazoan evolution and redox conditions, and thus insufficient to reconstruct an ecosystem that is an integrative entirety of biotic and abiotic components. Therefore, we proposed a facies-dependent integrative approach as a working hypothesis toward a more comprehensive understanding of ecosystem evolution during the Cambrian explosion.
    Abstract:
    In accordance with the cranidia structures, the method of “Q-mode cluster analysis” used in the present paper for a taxonomic study of 18 species of the genus Mufushania, that was established or adopted by Lin Tian-rui (1965), Li Shan-ji (1978),Zhang Wen-tang et al. (1980), Sun Zhen-hua (1982), Zhou Zhi-qiang et al. (1982), Guo Hong-jun et al. (1996), Yuan Jin-liang and Li Yue (1999), Peng Shan-chi et al. (2001), Yuan Jin-liang et al. (2002). The statistical measurement of similarity is incremental sum of error squares (ΔE). The use of the variability by the author is the eight quantitative ratio values (see table 1). The resemblance relation matrices of all specimens are formed through calculation of the increments of sum of error squares between those specimens (see table 2). These data show that M. shalangensis Zhang and Zhou in Zhang et al. 1980(5), M. angustilimbata Zhang and Zhou in Zhang et al.,1980 (7) and M. kailiensis (Yuan in Yuan et al., 2002) (13) species should not be a member of the Mufushania, not belonging to species of Mufushania. Finally, through the application of combined cluster analysis with traditional qualitative analysis in the study of fifteen species of Mufushania trilobites in this paper, of which M. changi Lin, 1965 (2) is regarded as a junior synonym of the type species (1) and M. zhanjiaxiangensis Sun, 1982 (10) is regarded as a junior synonym of M. ezhongensis Sun, 1982 (9), too, the other thirteen species of Mufushania in the opinion on lumping and transferring the studied species is proposed (see table 3).
    Abstract:
    The value of the discoveries of Hamipterus tianshanensis and their 3D eggs fossils?are of?great importance.?These fossils preserved in Beijing for several years, the surrounding rocks have been powdering and flaking, which seriously endanger the safety to fossils. This paper intends to use XRF and other methods to detect surrounding rock to explore its corrosion mechanism. The analysis shows that the surrounding rock of fossils is composed of sandstone with boulder clay, which contains some clay minerals such as montmorillonite. The?sandstone?with?calcareous?and?salt?cementation contains large amounts of soluble ions such as Cl-, NO3-, Na+ and Mg2+. The mechanism of the deterioration is as followed, when the humidity changes, the soluble salt also generates large crystal pressure, as well as the expansion of clay minerals produces huge pressing force, leading the surrounding rocks to powder and flake gradually. The?solution?of?salt?existing?as the cement results in the escape and?migration of?particles, which?is?an important reason for fossil deterioration.?Based on the above understanding, this paper also gives suggestions about the protection of fossils.
    Abstract:
    This study describes the Guadalupian (Middle Permian) fusulines from the northern Zhabuye area in the Lhasa Block and discusses their palaeobiogeography. In total, the fusuline fauna comprises 6 genera and 16 species, including Yangchienia tobleri Thompson, Yangchienia haydeni Thompson, Chusenella brevipola (Chen), C. schwagerinaeformis Sheng, C. cf. brevis (Chen), C. sp., Nankinella rarivoluta Wang, Sheng and Zhang, N. complanata Wang, Sheng and Zhang, Kahlerina tenuitheca Wang, Sheng and Zhang, K. pachytheca Kochansky-Devidé and Ramov?, Verbeekina americana Thompson, Wheeler and Danner, V. tenuispira Sheng, Neoschwagerina cheni Sheng, N. colaniae Ozawa, N. craticulifera (Schwager) and N. brevis Thompson, Wheeler and Danner. This fauna suggests a Wordian age, as evidenced by the presence of Kahlerina and the thick spirotheca and less-developed secondary transverse septula in Neoschwagerina species. The fauna from the Zhabuye area is correlatable with the contemporaneous faunas from other regions in the Lhasa Block including the Shiquanhe area, the Xiadong area in Tsochen County, Xainza County and Lhunzhub County. The synchronous appearances of Guadalupian warm-water fusuline faunas in the whole Lhasa Block exhibit a pronounced difference in palaeobiogeography from the Tethys Himalaya region with persistent cold-water brachiopod faunas during the middle and late Permian. It is unlikely that the Lhasa Block and the Tethya Himalaya region adjoined together before the late Triassic. Therefore, it is considered that the Lhasa Block has been separated from the Gondwanaland by Wordian time.
    Abstract:
    The Jurassic and Cretaceous strata in northern China are mostly of terrestrial origin. It presents a difficulty in defining the Jurassic-Cretaceous (J/K) boundary. In the previous biostratigraphic work, the J/K boundary was referred to a higher posi-tion of much younger age, which caused a big controversy between local biostratigraphy and the international standard. Re-cently, large quantity measurements of isotopic ages reveal that the J/K boundary is possibly within the Tuchengzi Formation. The formation is a group of terrestrial reddish sedimentary deposits, and divided into 3 members. It is the type sequence of terrestrial Jurassic-Cretaceous transition in northern China. The stratigraphic age of the formation is in disagreement, owing to more-or-less limited preservation of fossils and a contradiction between biostratigraphic and isotopic data. Certain fossil groups have been found in scattered beds, dominated by conchostracans, ostracodes, dinosaurs, spore and pollen. Further-more, the pronounced provincialism of the terrestrial fauna and flora obstructs global correlation. Paleontologists have al-ready produced many publications after hard work, and they gave different stratigraphic divisions. A large amount of isotopic dating provides reliable data showing that the duration of the Tuchengzi Formation is from 156 Ma to 139 Ma, covering the late Jurassic to early Cretaceous period. The J/K boundary lies within this interval. Huge chronostratigraphic data challenge the traditional biostratigraphic results. The chronostratigraphic unit, otherwise, has to be indicated by a biotic boundary marker. Before a biostratigraphic division of high precision has been worked out, we attempt to make an option for the J/K boundary marker according to the data in our possession. After recognizing the fossil assemblages, the location of the J/K boundary is between the Jurassic conchostracan Pseudograpta-Monilestheria-Sinograpta (P-M-S) and ostracode Cetacel-lasubstriata-Mantelliana alta-Darwinula bapanxiaensis (C-M-D) assemblages, and Cretaceous conchostracan Yanshano-leptestheria-Pingquania-Lingyuanella (Y-P-L) and ostracode Djungarica yangshulingensis-Mantelliana reniform-is-Stenestroemia yangshulingensis (D-M-S) assemblages. It is also indicated by the first appearance of spore and pollen Ci-catricosisporites-Lygodioisporites-Jiaohepollis (C-L-J) Assemblage. Lithologically, the boundary is between the members 2 and 3 of the Tuchengzi Formation and of ~145 Ma in age. The Batuying sections in Beipiao are recommended as the type sequence of the formation. Based on the occurrence of the earliest Cretaceous fossil assemblages in the member 3, we pro-pose a “Batuying Stage” as the lowermost terrestrial chronostratigraphic unit of the Cretaceous in China. The duration of the stage is 145–139 Ma, correlating roughly to the international Berriasian Stage. The members 1–2 are referred to the upper-most “5th stage” which approximately corresponds to the Kimmeridgian–Tithonian stages of the Upper Jurassic. The present suggestion is only to provide a consultation for the terrestrial Cretaceous chronostratigraphic study.
    Abstract:
    Trilobites are common fossil animals in the Cambrian. The fossil record of their healed exoskeletons can provide important information on the competitive arms-race relationship between trilobite prey and their potential predators in the Cambrian ecosystem. The early Cambrian Chengjiang biota from South China, well known for its exceptional fossil preservation, allows us to study the ancient ecological interactions in marine communities during the Cambrian explosion. However, there is no record of healed trilobites so far known from the Chengjiang biota. The trilobite Eoredlichia intermedia Lu, 1940, an index fossil of the second trilobite biozone in eastern Yunnan of China, is one of the commonest arthropods in the deposits. Of more than 2 000 specimens of E. intermedia in our collection, two adult specimens are revealed with deformities in the lateral margin of cephalon, genal spine, and the pleural region. We suggest that such injuries were most likely caused by unknown predators. The scalloped fractures or cracks on these two adult individuals were marginally thickened and smoothed at the edges, indicating obvious signs of healing. If interpreted exactly, these fossils lend some supports for the view that the victim Eoredlichia intermedia was capable of repairing their fractured exoskeletons from sub-lethal attack by unknown predators. Therefore, this research presents the thus-far oldest fossil record of trilobites with injuries and the first report of the trilobite exoskeleton with healed injuries from the Chengjiang biota, signifying an existing escalating arms race between durophagous predators and prey since Cambrian Stage 3.
    Abstract:
    Ostracods are described for the first time from the Late Ordovician in Nyalam, southern Xizang (Tibet), China. Thirty species belonging to sixteen genera are described and figured from the Jiaqu Formation in the Yalai Waterworks section. The ostracod fauna suggests a probable Sandbian-Katian Age for the Jiaqu Formation. The ecological assemblage of ostracods fauna belongs to the Eifelian Ecotype, which implies a nearshore depositional environment for the Jiaqu Formation. In the diverse ostracod fauna of the Jiaqu Formation, many cosmopolitan or provincial genera are shared in Himalaya, Tarim and South China, suggesting a close biogeographic relationship for the blocks.
    Abstract:
    Amber, as an organic gem, is fossilized natural resin widely distributed around the world, especially Baltic region in Europe, Dominica-Mexico in Central America, and Myanmar in Asia. Insects are the most common inclusions in amber, while verte-brate inclusions are the rarest. However, compared to vertebrate fossils from sedimentary rocks, vertebrate inclusions trapped in amber pieces can provide additional information about the soft tissues, primitive death states, and living environment, as well as more visualized and refined 3D morphological information, all of which are important for studies in evolution, palae-oenvironmental restoration, palaeoecology and palaeoethology, which is more intuitive, stereoscopic and detailed than bone fossils. This paper reviews vertebrate inclusions from various amber biotae, including non-avian dinosaurs, aves, mammals, reptiles and amphibians, as well as their evolutionary implication, and also provides a framework of future researches.
    Abstract:
    A new genus and species, Ayaimatum trilobatum gen. et sp. nov. Jiang and Szwedo, is described based on a planthopper preserved in mid-Cretaceous amber from Kachin State, northern Myanmar, and assigned to the Cretaceous planthopper fam-ily Mimarachnidae. A short overview of fossil record of the Mimarachnidae is given. The taxonomic diversity and morpho-logical disparity of this extinct group is briefly discussed.
    Abstract:
    This paper briefly summarizes the history of amber research in China and introduces the content of this special issue. The special issue includes 13 papers of 26 authors in 14 universities or institutes and covers some new progresses about plants, vertebrates, gastropods, and insects in mid-Cretaceous Kachin amber biota.
    Abstract:
    Re-examination of the holotype specimen of the clam shrimp type species Loxomegaglypta wetlugiana Novojilov, 1958 us-ing a scanning electron microscope (SEM) has revealed details of carapace features with important taxonomic value, which have never been described hitherto. The new features include: growth bands in the middle and ventral part of the carapace are ornamented with circular, angular or elliptical sieve-like fine pits (15 to 25 μm in diameter), which are surrounded by vari-ously shaped, wide swellings. Puncta (4 to 6 μm in diameter) occur not only in the pits, but also on the surrounding swell-ings. This ornamentation pattern is different from the originally described angular reticulation, and thus the diagnosis of Loxomegaglypta is emended.
    Abstract:
    Up to now, little is known about the palaeovegetation of the most northeastern part of the great Qinghai-Xizang (Tibet) Plateau during the Neogene time. In this study, we report Miocene pollen and spore assemblages from the Maladun Formation at Hongtupo, a small mountain about 50 km southwest of Songpan County town, Sichuan Province. The palynoflora is characterized by rich presence of Ulmaceae, Betulaceae and abundant Pinaceae pollen with rare spores. Angiosperm pollen occupies 52.9%–84.4% of the total tally. Gymnosperm pollen form 13.8%–44.1% of total pollen and spores. Spores only amount to 1.9%–5.1% of the total assemblage. Other elements in the pollen flora include common Fagaceae (Quercus, Castanea), Salix, Juglandaceae (Juglans, Carya) and minor Liquidambar, Sporotrapoidites, Lonicera, Ephedra, Compositae (Asteraceae), Rosaceae, Leguminosae (Fabaceae), Polygonaceae, Ranunculaceae, Lythraceae etc. Such a pollen flora represents a mixed broadleaved and conifer forest. The pollen flora of the Hongtupo is of late Early Miocene to early Middle-Miocene age based on the correlation with the similar pollen assemblage from the Lengshuigou Formation of Weihe Basin which was dated by the associated vertebrate fossils. The palaeoclimate derived from the pollen flora should be of cold temperate to temperate with an annual temperature of about 8℃–13℃. The present pollen flora shows a much less warm appearance than those of the similar age pollen floras from northern and eastern China, which leads to a deduction of palaeoaltitude at the fossil locality of over 1000 m to about 2000 m above sea level. It is interesting that the pollen flora also contains some warm-loving elements such as Liquidambar and Juglandaceae pollen, which probably implies the Miocene Hongtupo area was neighbored by a low terrace or valley landscape.
    Abstract:
    处于"寒武纪生命大爆发"序幕阶段的梅树村期,生物类群大规模辐射,身体构型快速革新,与前寒武纪生物群面貌明显不同.最近在陕南宁强宽川铺地区梅树村期地层中发现了大量五辐射Punctatus及部分四辐射四方塔形壳属Quadrapyrgites,其中包括1个新种Quadrnpyrgites undulatuscostalis sp.nov..在此基础上对Quadrapyrgites进行了属征补充.双胚层腔肠动物的出现标志着地球生命史的真后生动物演化开端,在生物起源演化历程上占据着关键的位置.本文为研究真后生动物起源演化、生物辐射、体型构建提供了重要实证.
    Abstract:
    本文描述湖北宜昌、兴山志留纪兰多维列世艾隆期蚜头虫类三叶虫Latiproetus latilimbatus(Grabau,1925)和Latiproetus tenuis Chang,1974的新材料.Latiproetus Lu,1962的有效性长期多有争论,通过新材料研究确认,该属和Prantlia P(r)ibyl,1946的区别在于其较短的鞍前区,向前收缩较少的头鞍,较微弱的尾肋沟和间肋沟,并不具鞍前区横脊.该属和Astroproetus Begg,1939的区别在于其较深的S1,清晰的S2,较小的活动颊刺,及宽而清晰的尾边缘.因此,笔者认为Latiproetus应为有效属.
    Abstract:
    40 years ago, the 3rd National Congress and the 12th Annual Conference of the Palaeontological Society of China was held in Suzhou of Jiangsu Province. The Congress has historical significance in the Chinese palaeontological development. Since 1979 the Chinese palaeontological research entered a new developmental stage, with excellent achievements springing up in large numbers, and frequent academic exchanges occurring. In the following years, the activities of the Society were more active than ever before, significant increase in membership, the activities of society had regularized. The Chinese paleontologists have returned to the international community with frequent exchanges.
    Abstract:
    新材料表明定远虫(Tingyuania)和双岛虫(Dinesus)这两个三叶虫属足有效的,前者并不是后者的晚出异名.双岛虫类的地质延限被下延至传统早寒武世晚期的清虚洞组.补允描述首次发现的定远虫的尾部,并描述双岛虫的一新种.
    Abstract:
    贵州独山的猴儿山组龙洞水段是一套浅海相碳酸盐沉积,盛产底栖牛物化石.通过对该段地层中所含四射珊瑚、床板珊瑚和腕足类等化石属种的详尽分析,再次证实龙洞水段的地质时代仍应属中泥盆世早期(Eifelian).而不是像某些根据痕迹化石或层序地层学的研究那样将它置于下泥盆统.
    Abstract:
    Thalattosaurs are one of the three major groups of top reptilian predators in the Triassic marine ecosystems, the study of which is a key to our understanding of biotic recovery from the Permo-Triassic mass extinction. Significant advancement has been achieved in the last decades in studying biodiversity and phylogeny of Thalattosaurs. However, the origin of Thalatto-saurs and the process forming the biogeographical pattern of Thalattosaurs largely remains an enigma. We review here the recent progress in the study of Thalattosaurs in terms of its origin, species diversity, phylogeny and biogeography. Our re-view shows that large gap exists in the research of Thalattosaurs. Future research should be focused on field work in the early part of the Triassic strata to search for more primitive Thalattosaurs. This is necessary to elucidate its origin. A first-hand systematic review of Thalattosaurs from SW China should be performed to clarify the true biodiversity of Thalat-tosaurs, which is also a basis for a comprehensive phylogenetic analysis of thalattosaurian relationships. Finally, the study of the physiology and paleoecology of Thalattosaurs via the investigation of long bone histology and microanatomy is of great significance in establishing the process forming the biogeographical pattern of Thalattosaurs.

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