Marine Micropaleontology 125 (2016) 51–65

Contents lists available at ScienceDirect

Marine Micropaleontology

journal homepage: www.elsevier.com/locate/marmicro

Biostratigraphy and biofacies of the Middle Darriwilian (Ordovician) conodonts from the Laoshidan section in the western margin of the North China Craton

Xiuchun Jing a,b,⁎, Hongrui Zhou b, Xunlian Wang a,b a State Key Laboratory of Geobiology and Environmental Geology, China University of Geosciences, Beijing 100083, China b School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China article info abstract

Article history: Middle Ordovician conodonts from the Sandaokan and Zhuozishan formations of the Laoshidan section at the Received 4 November 2015 western margin of the North China Craton, consist of 39 identified and six indeterminate species belonging Received in revised form 5 March 2016 to 21 genera, and three taxa left in open nomenclature at both genus and species levels. Of particular biostrati- Accepted 13 March 2016 graphic importance is the presence of morphologically advanced species of Histiodella associated with several Available online 16 March 2016 age-diagnostic endemic taxa, making it possible to recognize international conodont biozones in the main part Keywords: of the sequence. Three Histiodella-based zones are recognized in the studied section; including the Histiodella Ordovician cf. holodentata, Histiodella kristinae and Histiodella bellburnensis zones, in ascending order. They can be directly Conodonts correlated with the conodont zonations established in western Newfoundland, Canada and Tarim, western Biostratigraphy China, and compared well with the conodont biozones of Baltoscandia and Yangtze, central China. However, Biofacies the same stratigraphic interval on the North China Platform is barren of conodonts. Multivariate statistical studies North China on these conodonts allow recognition of four conodont biofacies: Scalpellodus biofacies, Panderodus biofacies, Drepanoistodus biofacies and Phragmodus biofacies. Turnovers of the conodont biofacies are related to either sea-level changes or mixing of shallow water conodonts due to down slope transportation. Excluding the effect of the allochthonous conodonts, the transgressive-regressive patterns demonstrated by the conodont biofacies compare closely to the published sea-level curves for the western margin of the North China Craton. © 2016 Elsevier B.V. All rights reserved.

1. Introduction supply excellent material for detailed description of the conodont pa- leoecology of the mid-Ordovician in North China. This paper presents Ordovician strata are extensively distributed along the western descriptions of the mid-Darriwilian conodont sequence and biofacies, margin of the North China Craton. These carbonate and clastic sedi- with the aims of revising the fauna to provide support for a more precise ments are biostratigraphically important because of the richness of biostratigraphic correlation, and examining the relationship between their macrofossils and microfossils, which have been successively stud- the turnovers of conodont biofacies and sea-level changes. ied since the 1950s (e.g., Lu, 1954; Mu, 1959; Zhang, 1959; Zhang, 1962; Chen, 1976; Wang and Luo, 1984; An and Zheng, 1990; Finney et al., 1999; Wang et al., 2013a; Jing et al., in press). Therefore, within the car- 2. Geological setting bonate successions of Ordovician sequences, conodonts are one of the most useful fossil groups for biostratigraphy and age dating. The tectonic framework of China includes three major continental- New conodont collections from the carbonate-dominant Sandaokan scale cratonic masses: the North China Craton, the South China block, and Zhuozishan formations of the Laoshidan section provide significant and the Tarim block (Fig. 1A). The North China Craton is bounded in new information on genera and species occurrences and ranges, and ne- the north by the Central Asian Orogenic Belt, in the west by the western cessitate revisions of and additions to the biostratigraphic data provided Tethyan subdomain, in the south by the Qinling–Tongbai–Hong'an– previously by Chen et al. (1984, Table 3); Wang and Luo (1984, p. 242– Dabie–Sulu orogenic belt, and in the east by the Pacific subduction 247) and An and Zheng (1990, p. 28–33). Moreover, these collections zone (Fig. 1A; also see Zheng et al., 2013). The North China Craton is one of the major Archean cratons in the world, and it comprises most of North China and parts of the Korean Peninsula (Fig.1B; also see Zhu ⁎ Corresponding author at: State Key Laboratory of Geobiology and Environmental Geology, China University of Geosciences, Beijing 100083, China. et al., 2012). The North China Craton experienced a long and com- E-mail address: [email protected] (X. Jing). plicated geological history, stabilizing during the Paleoproterozoic and

http://dx.doi.org/10.1016/j.marmicro.2016.03.002 0377-8398/© 2016 Elsevier B.V. All rights reserved. 52 X. Jing et al. / Marine Micropaleontology 125 (2016) 51–65 subsequently overlain by a thick succession of Neoproterozoic to Paleo- dominated deposition with Ordovician successions attaining 500– zoic sedimentary deposits (Zhao and Zhai, 2013; Zheng et al., 2013). 1000 m in thickness. Along the western to southwestern margin of The North China Craton was largely confined to the tropical zone the North China Craton even thicker accumulations (up to 2600 m) of near the equator during the Ordovician period (Zhen et al., 2015). mixed carbonates and siliciclastics were deposited in slope to marginal However, its paleogeographic position is still a controversial issue, that platform environments. was interpreted as a peri-Gondwanan terrane located along the north- Our study site is located in the northern part of the Helan Aulacogen east Gondwana margin and fringed by subduction–accretion complexes (Fig. 1B), which was connected to the western margin of the North China and island arcs (Metcalfe, 1996, 1998; De Jong et al., 2006; Metcalfe, Craton. The Helan Aulacogen, ~300 km in NNE trend, formed as a failed 2006) or as a part of eastern Gondwana until it was separated at rift relative to the Qinling and Qilian rifts during the Mesoproterozoic. the end of the Ordovician (Cho et al., 2014). Ordovician rocks on the Regional uplift during the Neoproterozoic resulted in formation of an un- North China Craton can be subdivided into two major depositional set- conformity, and subsidence during the earliest Paleozoic led to deposition tings, i.e., the broad North China Platform and the narrow western slope of Cambrian and Ordovician strata in shallow-marine to deep slope to southwestern marginal platform (Yang et al., 2005; Cao et al., 2011; settings (Lin et al., 1991). The Helan Aulacogen eventually closed in Feng et al., 2014; Zhen et al., 2015). The North China Platform, covered the Late Ordovician, and the subsequent uplift associated with the by a vast epicontinental sea, was the site of shallow water carbonate- Huaiyuan Epeirogeny II (lasting from the latest Ordovician to the latest

Fig. 1. (A) Simplified tectonic map of China showing major cratonic blocks and orogenic belts (from Zheng et al., 2013). (B) Map of North China Craton showing major tectonic stratigraphic framework of the Ordovician (modified after Zhu et al., 2012), and the location of the field area in the western Inner Mongolia region. The dashed ellipse indicates the approximate scope of the Helan Aulacogen. (C) Close-up map showing location of the successive two sections in the vicinity of the town of Laoshidan. Black star indicates the locality of the Laoshidan section, black dot shows the locality of the Wolonggang section. Gray areas indicate Ordovician outcrop exposures. X. Jing et al. / Marine Micropaleontology 125 (2016) 51–65 53

Mississippian) resulted in the absence of a Silurian through Mississippian 1984, respectively. H. cf. holodentata is the most age-diagnostic taxon succession in this region and other parts of the North China Craton (Zhen of this interval, which was proposed by Stouge (2012) to accommodate et al., 2015). In comparison with major eustatic sea-level changes, the an intermediate form species between H. holodentata and H. kristinae. Huaiyuan Epeirogeny played a decisive role in shaping and controlling The Pa element of H.cf.holodentata has a cusp as high as the tallest an- the regional stratigraphy and sedimentation of the North China Craton terior denticle, the apexes of the cusp and the tallest anterior denticle during the Ordovician (Zhen et al., 2015). The Ordovician succession form a line parallel to the aboral margin in lateral view (Stouge, 2015, of the Laoshidan section was deposited during a time interval, in personal communication). In our collections, only one specimen which the basement subsidence coupled with a major eustatic (Fig. 7: 1) is badly preserved in sample L-3-3, while its tall and apically sea-level rise, between the Event 1 and Event 2 of the Huaiyuang free anterior denticles are associated a prominent cusp and represent Epeirogeny (Zhen et al., 2015). the characters of H. cf. holodentata rather than H. holodentata. Myrow et al. (2015) reported the H. holodentata Zone in the Sandaokan Forma- 3. Lithostratigraphy tion of the Subaiyingou section which is about 30 km northeast to the Laoshidan section, but their specimens (Myrow et al., 2015, Fig.14: A- Conodonts were obtained from the Laoshidan section (39°22′53″N, C) are also poorly preserved and closely similar to H. cf. holodentata. 106°51′58″E; Fig. 1C) which is located in the Laoshidandongshan Moun- The interval referred to as the H. holodentata Zone by Myrow et al. tain and approximately 2 km east of the town of Laoshidan, Inner (2015) most probably represents the H.cf.holodentata Zone. The nom- Mongolia, North China. Ordovician rocks are well exposed along the inal species has been reported from Tarim (=H. holodentata of Du et al., trend of the Laoshidandongshan Mountain, so we measured the study 2005, Pl. 1: 22, 28; = H.sp.AofStouge et al., 2011), Yangtze (=H. section along a west–east path that is perpendicular to the ridgeline tableheadensis of Zhang, 1998;=H. holodentata of Chen et al., 2006), and passes over the mountain. Lithologies in this section are sandstone, Newfoundland (=H. tableheadensis of Stouge, 1984, only Pl. 18: 12), dolostone and limestone that strike 110° to 115° and dip 33° to 35°. The Quebec (=H.sp.ofMaletz, 2009) and Argentine Precordillera (=H. Ordovician lithostratigraphic scheme in the study area was initially pro- kristinae of Feltes et al., 2013; Feltes et al., 2016). Stouge (2012) posed by Lu (1954) and then was reviewed by Chen et al. (1984).This established the H.cf.holodentata Phylo-subzone, which is subordinate lithostratigraphic scheme has been widely accepted (e.g., Wang and to the Periodon macrodentatus Phylozone and was assigned to the Luo, 1984; An and Zheng, 1990; Feng et al., 1998, 2004; Wang et al., lower Dw2 stage slice of Bergström et al. (2009). Due to the significant 2013a; Myrow et al., 2015), and is also adopted in the present paper. transgression of the Sandaokan Formation, the appearance of H.cf. The Laoshidan section consists of the Middle Ordovician Sandaokan holodentata in the study section should be attributable to an immigra- and Zhuozishan formations in ascending order. The Sandaokan Forma- tion event, which means the replacement of H. holodentata by H.cf. tion, unconformably underlain by the Cambrian Abuqiehai Formation, holodentata (i.e., the base of the H.cf.holodentata Phylo-subzone of is represented by a series of gray to dark-gray quartzose sandstone Stouge, 2012) is unrecorded in the study section. The accompanying and dolomitic quartzose sandstone with some intercalations of taxa have longer stratigraphic ranges than does the zonal species. dolostone (Fig. 2). The sandstone lithofacies and the presence of some Therefore, this interval zone corresponds to the upper part of the H.cf. sedimentary structures formed under the shallow water and high- holodentata Phylo-subzone of Stouge (2012), and is interpreted to be energy flows (such as parallel lamination and trough cross- lower Dw2 with the exception of the basal part of this stage slice. stratification), in combination with sandstone-filled paleokarst clearly Histiodella kristinae Phylozone — The next younger zone covers the indicate a shoreline environment of this formation (Myrow et al., strata from 83.63 m to 360.9 m above the base of the study section. 2015). The Zhuozishan Formation is composed dominantly of thick- This interval recorded the occurrence of 24 species from the section, bedded limestone with intercalated thin-bedded argillaceous limestone including: Ansella longicuspica Zhang, 1998, Aurilobodus leptosomatus An and nodular limestone, the thick-bedded limestone was normally mod- et al., 1983, Cornuodus longibasis (Lindström, 1955), Cornuodus sp., erately or severely bioturbated (Fig. 2). The association of carbonate de- Drepanodus reclinatus (Lindström, 1955), Drepanoistodus basiovalis, posits suggests the general depositional environments of the D. costatus, D.sp.,Histiodella kristinae, H. wuhaiensis Wang et al., 2013b, Zhuozishan Formation were the proximal (Myrow et al., 2015)tomid- Juanognathus sp., Loxodus dissectus An et al., 1983, Nealeodus aff. dle part of a carbonate shelf upwards. It should be noted that Myrow martinpointensis Stouge, 2012, Panderodus nogamii, P. sulcatus et al. (2015) referred the lower part of the Zhuozishan Formation (Fåhræus, 1966), Parapanderodus arcuatus Stouge, 1984, P. (99.5–138 m of their stratigraphy column) to the Sandaokan Formation. paracornutiformis (Ethington and Clark, 1982), Parapanderodus striatus A fault is evidently present at the endpoint of this section, and recon- (Graves and Ellison, 1941), Parapaltodus simplicissimus Stouge, 1984, structed the top part of the Zhuozishan Formation. This fault is also the Paroistodus horridus (Barnes and Poplawski, 1973), P. originalis boundary of the Zhuozishan Formation in the Laoshidan section and the (Sergeeva, 1963), Phragmodus sp., Scalpellodus gracilis (Sergeeva, 1974), overlying Klimoli Formation in the Wolonggang section sensu Jing et al. S. pointensis, Semiacontiodus cornuformis, Triangulodus maocaopus Zhang, (in press). 1998, Tripodus laevis (Bradshaw, 1969). The base of this phylozone is marked by the first appearance of H. kristinae, and the top is defined by 4. Conodont biostratigraphy the first appearance of the descendant H. bellburnensis. Biostratigraphically, H. kristinae is the most significant species in Most samples from the study section yielded conodonts (Table 1; this zone, along with two regionally important age-diagnostic taxa Fig. 2). The following three Histiodella-based biozones are recognized, Aurilobodus leptosomatus and Loxodus dissectus. The zonal index, H. in ascending order: the Histiodella cf. holodentata Zone, the Histiodella kristinae, is widely distributed in North America (Barnes and kristinae Zone and the Histiodella bellburnensis Zone. Poplawski, 1973; Landing, 1976; Nowlan and Thurlow, 1984; Histiodella cf. holodentata Interval Zone — The lowest zone ranges Stouge, 1984), Europe (Dzik, 1994; Rasmussen, 2001; Löfgren, from 48.37 m to 83.63 m above the base of the Laoshidan section and 2004), Argentine Precordillera (Heredia et al., 2005; Serra and Albanesi, is characterized by the occurrence of H. cf. holodentata Ethington and 2013; Serra et al., 2013, 2015; Feltes et al., 2016), South China (Ni, Clark, 1982 along with Ansella crassa Bauer, 1994, Baltoniodus medius 1981; Wang, 1993; Zhang, 1998), North China (Wang and Luo, 1984; (Dzik, 1976), Drepanoistodus basiovalis (Sergeeva, 1963), D. costatus An and Zheng, 1990; Wang et al., 2013a), and Tarim (Wang and Zhou, (Abaimova, 1971), D.sp.,Panderodus nogamii (Lee, 1975), Scalpellodus 1998; Zhao et al., 2000; Du et al., 2005; Zhen et al., 2011). The pointensis Stouge, 1984,andSemiacontiodus cornuformis (Sergeeva, stratigraphic range of the nominal species has been subjected to debate 1963). The base and top of this zone are defined by the appearances of among conodont workers (e.g., Du et al., 2005; Bergström et al., 2009; Histiodella cf. holodentata and the next zonal index H. kristinae Stouge, Zhen et al., 2011; Wang et al., 2013a; Serra et al., 2015; Feltes et al., 54 X. Jing et al. / Marine Micropaleontology 125 (2016) 51–65

Fig. 2. Stratigraphical ranges of selected conodont species and stratigraphical distribution of conodont biofacies in the Laoshidan section.

2016). On the basis of collections from Tarim and western Newfoundland, (2011) and Stouge (2012) is followed herein. Moreover, Wang et al. Stouge et al. (2011) and Stouge (2012) included the H. kristinae Phylo- (2013a) recognized the H. kristinae Zone in the Lower Klimoli Formation, subzone in the Periodon zgierzensis Zone and correlated the former with which is underlain by the Zhuozishan Formation at the Dashimen section the middle Dw2 stage slice. Given that the other coexisted species in (approximate 12 km northwest to the study section). In the present this zone are all relatively long ranging and of little use in age- study, the Lower Klimoli Formation of the Dashimen section sensu definition, the age determination of this zone made by Stouge et al. Wang et al. (2013a) and the middle part of the Zhuozishan Formation X. Jing et al. / Marine Micropaleontology 125 (2016) 51–65 55 of the Laoshidan section are considered as belonging to different and H. bellburnensis, and its stratigraphic range close to the lineage lithofacies of the same period, for a severe facies change can be observed replacement of the later two well known Histiodella species (Fig. 2). Ac- in the study area (e.g., An and Zheng, 1990; Feng et al., 1998). cordingly, H. wuhaiensis probably represents an evolutionary continuum On a separate note, two coexisted conodonts, Aurilobodus between H. kristinae and H. bellburnensis. However, the spatial and leptosomatus and Loxodus dissectus, are both relatively widely distributed temporal distribution of H. wuhaiensis is ill-defined, which hinders the and biostratigraphically useful species. A. leptosomatus was reported usefulness of this species as a biostratigraphical marker. It is anticipated from North America (=Juanognathus aff. variabilis of Harris et al., that further investigations in the study area will have high potential 1979;=Juangognathus serpaglii of Stouge, 1984), North China (An to provide a more detailed conodont biostratigraphic framework based et al., 1983; An and Zheng, 1990; Wang et al., 2014b), Australia on the Histiodella lineage – the H. wuhaiensis Zone is expected to be (Watson, 1988; Stait and Druce, 1993; Kuhn and Barnes, 2005)and erected. Since all the accompanying taxa in this zone have long or uncer- Southern Asia (Agematsu et al., 2006, 2008a, 2008b). It has a stratigraphic tain stratigraphic ranges with less biostratigraphic significance, the dating range confined to the H. holodentata-T. tangshanensis Zone in the North of Stouge (2012) for the H. bellburnensis Phylo-subzone is followed herein China Platform (An et al., 1983; Wang et al., 2014b), while co-occurs as a chronostratigraphic marker. with H. kristinae in the Laoshidan section (this paper) and accompanies Plectodina onychodonta in western Thailand (Agematsu et al., 2008b). 5. Correlations Plectodina onychodonta is a common species stratigraphically distributed in the Eoplacognathus suecicus Zone of North China (An et al., 1983; The present Histiodella-bearing conodont fauna offers a great poten- Wang et al., 2014b; Jing et al., in press). Therefore, A. leptosomatus ranges tial for global correlation as some species are recorded from elsewhere from the H. holodentata Zone to the E. suecicus Zone, and corresponds to in China, North America, South America and Baltoscandia. Nevertheless, the stratigraphic interval from the mid-Dw1 to the top of the Dw2. the investigated fauna is not that similar to co-eval faunas in the latter Loxodus dissectus is a morphologically distinctive species and has a regions as the disappearance of the common co-occurring pectiniform distribution in North China (An et al., 1983;=L.sp.ofWang and Luo, species (such as Dzikodus tablepointensis, Polonodus newfoundlandensis, 1984; An and Zheng, 1990; Wang et al., 2014b), central Australia the Yangtzeplacognathus and Eoplacognathus species) in the study sec- (=Appalachignathus?sp.nov.AofStait and Druce, 1993, only Fig.16:E), tion. However, these pectiniform species were reported from the Newfoundland (=L.? curvatus of Stouge, 1984) and Quebec (=Coleodus? Klimoli Formation of the Wolonggang section which just overlies the sp. of Barnes and Poplawski, 1973). This taxon has the same stratigraphic Zhuozishan Formation of the study section (Jing et al., in press). The range as that of A. leptosomatus in the North China Platform (An et al., combination of the Zhuozishan and Wolonggang sections can provide 1983; Wang et al., 2014b). The occurence of L. dissectus above the range a fine constraint to correlate the Histiodella-based zonation. The correla- of H. bellburnensis implies that the stratigraphic range of this species is tions are shown in Fig. 3. from the middle Dw1 to the middle Dw2. Western Newfoundland — conodonts from the Table Head Group at Histiodella bellburnensis Phylozone — This zone is defined by the Table Point section were comprehensively studied by Stouge the whole range of H. bellburnensis Stouge, 1984 from 360.9 m to (1984) and were re-assessed recently by Stouge (2012). The Darriwilian 433.55 m above the base of the study section. Being the most diverse in- Periodon-based phylozones and Histiodella Sub-biozones proposed by terval in the Laoshidan section, this zone yields 32 identified and 5 un- Stouge (2012, Fig. 8) are considered as a standard reference for western identified species including Ansella jemtlandica (Löfgren, 1978), Ansella Newfoundland in this paper. The Darriwilian conodont fauna from the longicuspica, Baltoniodus sp., Cornuodus longibasis, Costiconus ethingtoni Laoshidan section shows a general similarity — on the species level — (Fåhræus, 1966), Drepanodus reclinatus, Drepanoistodus basiovalis, to that from the Table Point section (Stouge, 1984). Both sections D. suberectus (Branson and Mehl, 1933), D. tablepointensis Stouge, share the key Histiodella species, which allows a relatively straightfor- 1984, Dzikodus sp., Histiodella bellburnensis Stouge, 1984, H. kristinae, ward biostratigraphic correlation (Fig. 3). The H. kristinae and H. H. wuhaiensis, Loxodus dissectus, Nealeodus aff. martinpointensis, bellburnensis zones of the Laoshidan section can be correlated with the Panderodus nogamii, P.cf.nogamii, P. sulcatus, Parapaltodus simplicissimus, eponymous phylo-subzones of the Table Point section, the H.cf. Parapanderodus arcuatus, P. paracornutiformis, P. striatus, Paroistodus holodentata Zone of the study section compares to the upper part of horridus, P. originalis, Periodon cf. zgierzensis (Dzik, 1976), Phragmodus the cognominal phylo-subzone in western Newfoundland. Regrettably, paraundatus Wang and Luo, 1984, Protopanderodus cf. varicostatus only three specimens of Periodon cf. zgierzensis,restrictedtotheH. (Sweet and Bergström, 1962), P. graeai (Hamar, 1966), P. rectus bellburnensis Zone (Fig. 2), were obtained from two samples in our col- (Lindström, 1955), Scalpellodus gracilis, S. pointensis, Triangulodus lection (Table 1), which hampers the correlation of the Periodon-based maocaopus, Tripodus laevis, Gen. et sp. indet. A, Gen. et sp. indet. B and zones between western Newfoundland and Laoshidan. Gen. et sp. indet. C. The morphologically distinctive H. bellburnensis has Tarim — based on the conodonts obtained from the Dawangou For- been previously reported only from western Newfoundland (Stouge, mation and the Saergan Formation of the Tarim Basin, western China, 1984), Tarim (Du et al., 2005) and Argentina (Serra et al., 2013, 2015), Stouge et al. (2011) outlined a Darriwilian conodont biostratigraphic this study is the first report of this species in North China. The zonal framework nearly the same as that in western Newfoundland (Fig. 3). index species is a biostratigraphically important conodont species in the The biostratigraphic correlations between Laoshidan and Tarim are Darriwilian age, but the correlation of the zone with the Baltoscandian also comparatively simple. The H. kristinae and H. bellburnensis Zones succession were debated among conodont biostratigraphers (Stouge, of the present study coincide with the homonymous phylo-subzones 1984, 2012; Du et al., 2005; Stouge et al., 2011; Serra et al., 2013, 2015). in Tarim, the H.cf.holodentata Zone of the study section is coeval to More recent information shows that this zone may overlap or be as the H. sp. A Subzone of the Yangjikan section because Histiodella sp. A young as E. suecicus Zone (e.g., Serra et al., 2015), but this biostratigraphic sensu Stouge et al., 2011 is a former open nomenclature of H.cf. problem is still not yet solved (Stouge, 2015, personal communication). holodentata (Stouge, 2015, personal communication). Du et al. (2005) Although Stouge (2012) and Serra et al. (2015) attributed the recognized four Histiodella phylozones on the basis of a large collection H. bellburnensis Zone to the upper Dw2 stage slice, we follow Stouge's from the Yanjikan section and other localities of the Tarim Basin, in as- opinion (2015, personal communication) on how to correlate this zone cending order: the H. sinuosa Zone, the H. holodentata Zone, the H. pending further study. kristinae Zone, and the H. bellburnensis Zone. Stouge (2012), however, A morphologically distinctive associated species H. wuhaiensis, suggested that H. holodentata sensu Du et al. (2005) includes H.cf. which was originally erected by Wang et al. (2013b), has a blade-like holodentata,thustheH.cf.holodentata Zone of the present paper corre- Pa element with a downwardly arched aboral margin in lateral view. sponds to the top part of the H. holodentata Zone sensu Du et al. (2005). This species shows close morphological similarities to both H. kristinae With the erection of H. wuhaiensis, Wang et al. (2013b) considered the 56

Table 1 List of conodont species from the Laoshidan section.

Samples L-3-1 L-3-2 L-3-3 L-5-2 L-5-3 L-5-4 L-5-5 L-6-1 L-6-2 L-6-3 L-7-1 L-8-1 L-9-1 L-10-1 L-10-2 L-11-1 L-11-2 L-11-3 L-12-1 L-12-2

Species

Ansella crassa 1 Ansella jemtlandica var. Ansella jemtlandica Ansella longicuspica 1 Aurilobodus leptosomatus 11 1 Baltoniodus medius 1 Baltoniodus sp. Cornuodus longibasis 11 Cornuodus sp. 1 Costiconus ethingtoni Drepanodus reclinatus 1

Drepanoistodus basiovalis 3111 51 (2016) 125 Micropaleontology Marine / al. et Jing X. Drepanoistodus costatus 23 1 3 11 Drepanoistodus sp. 2 5 1 1 Drepanoistodus suberectus Drepanoistodus tablepointensis Dzikodus sp. Histiodella bellburnensis Histiodella cf. holodentata 1 Histiodella kristinae 1 Histiodella wuhaiensis Juanognathus sp. 31 Loxodus dissectus 111 1 3 Nealeodus aff. Martinpointensis 1 Panderodus nogamii 4 3 11 42 1 Panderodus cf. nogamii Panderodus sulcatus 12 Parapaltodus simplicissimus Parapanderodus arcuatus 12 –

Parapanderodus paracornutiformis 11 65 Parapanderodus striatus 1 Paroistodus horridus Paroistodus originalis 11 Periodon cf. zgierzensis Phragmodus paraundatus Phragmodus sp. 1 Protopanderodus cf. varicostatus Protopanderodus graeai Protopanderodus rectus Scalpellodus gracilis 21 Scalpellodus pointensis 111 4 2 4 13 Semiacontiodus cornuformis 21 1 1 Triangulodus maocaopus Tripodus laevis Gen. et sp. indet. A Gen. et sp. indet. B Gen. et sp. indet. C 1 Total no. of specimens 8 3 10 3 1 1 3 3 5 1 14 3 13 11 2126212 Table 1 (continued)

Samples L-13–1 L-13–2 L-14-1 L-16–1 L-16–2 L-17–1 L-18–1 L-18-3 L-19–1 L-19-2 L-20-1 L-21-1 L-21-3 L-22-1 L-22-2 L-22-3 L-23–1 L-23–2 Total

Species

Ansella crassa 1 Ansella jemtlandica var. sp. 1 1 Ansella jemtlandica 11 1 1 5 119 Ansella longicuspica 535 14 Aurilobodus leptosomatus 2 5 Baltoniodus medius 1 Baltoniodus sp. 13 4 Cornuodus longibasis 1241 10 Cornuodus sp. 1 Costiconus ethingtoni 141 17 Drepanodus reclinatus 12 15 Drepanoistodus basiovalis 511311128 Drepanoistodus costatus 11 51 (2016) 125 Micropaleontology Marine / al. et Jing X. Drepanoistodus sp. 9 Drepanoistodus suberectus 11 2 Drepanoistodus tablepointensis 41 1 1 7 Dzikodus sp. 11 2 Histiodella bellburnensis 3144 12 Histiodella cf. holodentata 1 Histiodella kristinae 815143 41 Histiodella wuhaiensis 11 2 Juanognathus sp. 4 Loxodus dissectus 2 110 Nealeodus aff. Martinpointensis 1 2 Panderodus nogamii 2 1 2 8 3 61 12 1 1 1 1 1 110 Panderodus cf. nogamii 1 1 Panderodus sulcatus 32 2 1 112 Parapaltodus simplicissimus 14 712 15 Parapanderodus arcuatus 14 264 20

Parapanderodus paracornutiformis 1 3 – 65 Parapanderodus striatus 32211111 Paroistodus horridus 161157 1 31 Paroistodus originalis 34 9 Periodon cf. zgierzensis 12 3 Phragmodus paraundatus 236 8 10 254 Phragmodus sp. 1 Protopanderodus cf. varicostatus 27 2 1 12 Protopanderodus graeai 3146 23 Protopanderodus rectus 3 3 Scalpellodus gracilis 1 4 Scalpellodus pointensis 54 13 1 40 Semiacontiodus cornuformis 16 Triangulodus maocaopus 12 1 4 Tripodus laevis 13 1 5 Gen. et sp. indet. A 1 1 Gen. et sp. indet. B 51 6 Gen. et sp. indet. C 5 17 Total no. of specimens 5 11 10 74 251 9 166 80 2 41 2 2 3 1 1 5 2 2 780 57 58 X. Jing et al. / Marine Micropaleontology 125 (2016) 51–65

Fig. 3. Correlation of the Ordovician conodont zonation of the Laoshidan section (this paper) and the Wolonggang section (Jing et al., in press) with those of the North China Platform (An et al., 1983; Wang et al., 2014b), western Newfoundland (Stouge, 1984, 2012), Tarim (Stouge et al., 2011), Yangtze (Zhang, 1998), Baltoscandia (Löfgren and Zhang, 2003; Löfgren, 2004; Bergström, 2007; Mellgren and Eriksson, 2010) and Argentine Precordillera (Albanesi and Ortega, 2002; Albanesi et al., 2013; Serra et al., 2015; Feltes et al., 2016). Abbreviations: SC. = section, FM. = Formation, B.A.Z. = Beianzhuang, SAN. = Sandaokan.

specimens of H. bellburnensis illustrated by Du et al. (2005) to represent hindered by the fact that the zonal index species has not been found two separate species, namely H. wuhaiensis and H. bellburnensis sensu in Baltoscandia (Stouge, 2015, personal communication). Stouge, 1984. Given that the first appearance datum of H. wuhaiensis is Yangtze — the Darriwilian conodont faunas from the Yangtze older than that of H. bellburnensis in the Laoshidan section, the base of Platform and Baltoscandia show a general similarity at the species the H. bellburnensis Zone of Du et al. (2005) most likely represents the level, which led to two highly similar conodont biostratigraphic first occurrence of H. wuhaiensis rather than that of H. bellburnensis schemes being established for the two long-distance regions (Zhang, sensu Stouge, 1984. Zhen et al. (2011) resampled the Dawangou section 1998). As in Baltoscandia, Histiodella species comprised also a minor and recognized six conodont zones in ascending order: the Y. crassus, component of the Darriwilian conodont faunas in Yangtze. Specimens the H. holodentata,theH. kristinae,theP. serra,theP. anserinus,and reported as H. tableheadensis sensu Zhang (1998) and H. holodentata the B. alobatus Zones. According to their material, H. holodentata occurs sensu Chen et al. (2006) from Yangtze were reassigned to H.cf. above the range of Y. crassus in the Dawangou section, which makes the holodentata by the present authors and Stouge (2012),respectively. correlations of the H. holodentata Zone tangled. Considering that the Biostratigraphically, Histiodella cf. holodentata has a range spanning specimens of Zhen et al. (2011, Fig. 14: A-B) show some rather distinc- the upper part of the Y. crassus Zone to the lowermost part of the tive characters of H.cf.holodentata, we prefer to assign their specimens M. ozarkodella Subzone of the D. tablepointensis Zone and without over- to this taxon. Therefore, the present H.cf. holodentata Zone is at the level lapping with the range of H. kristinae in Yangtze (Zhang, 1998; Chen equivalent to the H. holodentata Zone of Zhen et al. (2011). et al., 2006), which indicates a correlation of the H.cf.holodentata Baltoscandia — Southern Sweden is the most intensively studied area Zone with the stratigraphic interval from the Y. crassus Zone to the low- in Baltoscandia for research on Ordovician conodonts. The vertical ermost part of the M. ozarkodella Subzone of the Yangtze succession. ranges and biostratigraphy of the Darriwilian conodonts from southern Based on a collection of more than 46,000 identified conodont speci- Sweden were presented by Löfgren and Zhang (2003); Löfgren (2004); mens from the Guniutan Formation of South China, Zhang (1998) Bergström (2007) and Mellgren and Eriksson (2010). The Histiodella recorded 43 P elements of H. kristinae with a stratigraphic range con- species were obtained as a minor component in Baltoscandia, but pro- fined to the M. ozarkodella Subzone of the D. tablepointensis Zone. In vide useful biostratigraphic ties with the coeval conodont faunas from the H. bellburnensis Zone of the present study, we obtained several frag- elsewhere. Histiodella holodentata s.s. in Baltoscandia is restricted to mentary specimens of Dzikodus (e.g., Fig. 6: 35) that are reminiscent of the Lenodus variabilis Zone (Stouge and Nielsen, 2003; Mellgren and D. tablepointensis. Hence, it is best to consider both the H. kristinae and Eriksson, 2010), some other specimens reported as H. holodentata the H. bellburnensis Zones at the interval equivalent to the M. ozarkodella (Rasmussen, 2001; Löfgren, 2004) were reassigned to H. kristinae by Subzone of the D. tablepointensis Zone. Since the top of the D. Zhen et al. (2011), these imply that the H. holodentata Zone is coeval tablepointensis Zone was recorded in the younger Klimoli Formation to the L. variabilis Zone. However, the correlations of the younger H. (Jing et al., in press), we correlated the H. kristinae Zone and the H. kristinae and H. bellburnensis zones with the Baltoscandian succession bellburnensis Zone separately with the lower and middle part of the M. were debated among conodont workers (e.g., Rasmussen, 2001; ozarkodella Subzone. Löfgren, 2004; Du et al., 2005; Bergström et al., 2009; Zhen et al., Argentine Precordillera — Serra et al. (2015) and Feltes et al. (2016) 2011; Wang et al., 2013a; Serra et al., 2015). Histiodella kristinae (includ- most recently investigated the Ordovician conodonts of the Las ing both H. holodentata and H. kristinae of Löfgren, 2004) has a strati- Chacritas River and Las Aguaditas Creek sections in Precordillera of graphic range confined to the Microzarkodina ozarkodella Subzone in San Juan, western Argentina. The conodont faunas in these two sections south-central Sweden (Löfgren, 2004), which suggests a correlation are of North Atlantic Provincial affinity, while the co-occurrence of some between the H. kristinae Zone and the M. ozarkodella Subzone of the morphologically advanced Histiodella species allows a correlation be- E. pseudoplanus Zone. Whereas efforts to correlate the H. bellburnensis tween the Histiodella-based zonation and the Baltoscandian conodont Zone with the Baltoscandian conodont zonation have been largely zonal succession. Serra et al. (2015) recognized the H. sinuosa, H. X. Jing et al. / Marine Micropaleontology 125 (2016) 51–65 59 holodentata, H. kristinae and H. bellburnensis subzones in the San Juan discriminated within the succession of the Sandaokan and Zhuozishan and Las Chacritas formations of the Las Chacritas River section, and formations, i.e., Panderodus biofacies, Scalpellodus biofacies, correlated these four subzones with the L. variabilis, Y. crassus to E. Drepanoistodus biofacies and Phragmodus biofacies (Fig. 4A). The pseudoplanus,lowerE. suecicus and upper E. suecicus zones, respectively. Detrended Correspondence Analysis (DCA) depicts a trend for the four co- Shortly afterwards, Feltes et al. (2016) identified the H. sinuosa, H. nodont biofacies extending from the Scalpellodus biofacies, to holodentata and H. kristinae subzones in the San Juan and Las Aguaditas Drepanoistodus biofacies to Phragmodus biofacies along the first axis formations of the Las Aguaditas Creek section, and correlated them sep- (Fig. 4B), which may re flect a profile from the inner shelf to mid-shelf arately to the lower L. variabilis, upper L. variabilis to lower E. or shelf margin environments. The second axis extending from the pseudoplanus – D. tablepointensis,andupperE. pseudoplanus – D. Panderodus biofacies to Phragmodus biofacies indicate a tendency from tablepointensis zones, respectively. These biostratigraphic correlations shallow to deeper water settings. Interestingly, our conodont biofacies provided a more detailed comparison for the Histiodella lineage, and are a parallel to the mid-Ordovician conodont biofacies — the are both regionally and internationally complementary. What should Scalpellodus–Microzarkodina biofacies, Baltoniodus biofacies, be noted is that the H. bellburnensis Zone in Argentine Precordillera is Drepanoistodus biofacies and Protopanderodus–Periodon biofacies – were stratigraphically much younger than the homonymous zone in the identified by Rasmussen and Stouge (1995) from the carbonate platform study area (Fig. 3). This stratigraphical disagreement is considered as of Baltica. These biofacies were interpreted by the same authors as the H. bellburnensis Zones of the two long-distance regions represent representing shallower to deeper environments, respectively. different intervals of the whole range of the nominal species. Four horizons of the Laoshidan section yield highly abundant North China Platform — domination of endemic Darriwilian Panderodus nogamii, which is characterized by the Panderodus biofacies. conodonts in the carbonate platform facies (equivalent to today's cen- The nominal genus Panderodus is a common genus in high-energy near- tral North China) of the North China Craton makes the precise age deter- shore environments (Aldridge, 1976; Le Fèvre et al., 1976; Aldridge and mination and international correlation of the fauna difficult (An et al., Jeppsson, 1984; Sweet, 1988; Zhang et al., 2006). These characteristic 1983; An and Zheng, 1990; Wang et al., 1996). Most recently, Wang living habits are consistent with the sedimentological evidences, the et al. (2014b) re-assessed the conodont zonation of the Zhaogezhuang strata identified to be Panderodus biofacies are grainstone or grain section in Tanshan, Heibei Province, which is a representative mid- dolostone with one exception, however, in the H. bellburnensis Zone Ordovician section in the platform facies of North China. Based on a (see below). Accordingly, the Panderodus biofacies is indicative of a few pandemic zonal taxa obtained in the conodont fauna, they erected shallow, high-energy, temperate to warmer water environment charac- the Histiodella holodentata–Tangshanodus tangshanensis Zone in the teristic of the proximal shelf environment. upper part of the Beianzhuang Formation and the Eoplacognathus The Scalpellodus biofacies is easy to recognize by the abundance of suecicus Zone in the upper part of the Machiakou Formation. However, S. pointensis. In this biofacies, Aurilobodus and Loxodus have affinities the lower parts of these two formations are all with rare conodonts to the warm water fauna on the North China Platform (An et al., 1983; and were not enough to recognize or establish conodont zones Wang et al., 2014b). A similar biofacies had been recognized in western (Fig. 3). Correlations of the conodont zones indicate that the Sandaokan Newfoundland (Stouge, 1984) and the Baltic region (Rasmussen and and Zhuozishan formations of the Laoshidan section coincide with the Stouge, 1995). Stouge (1984) demonstrated that Scalpellodus inhabited lower part of the Machiakou Formation of the Zhaogezhuang section, the relatively shallow waters on the shelf with normal temperatures unfortunately, the latter is barren of conodonts. and salinities; he further interpreted this biofacies to typify the offshore, relatively deeper and muddier low energy environment (below wave 6. Conodont biofacies and sea-level changes base). Rasmussen and Stouge (1995) suggested that this biofacies rep- resents a shallow, subtidal environment. These observations are in Since the early 1960s, it has been known that the occurrence and rel- accordance with the analysis presented here (Fig. 4B), where the ative abundance of certain conodont genera and species were related to Scalpellodus biofacies occupies the leftmost position with respect to the surrounding environments (e.g., Müller, 1962). However, conodont the first axis. Thus, the Scalpellodus biofacies recognized in our study paleoecology and biofacies models have been explored since at least the section is interpreted as representing a shallow, subtidal, warm water 1970s, when the Seddon and Sweet (1971) and the Barnes and Fåhraeus environment. (1975) were proposed. Later, it was further confirmed that most cono- The Drepanoistodus biofacies covers the H. bellburnensis Zone of the dont species seem to fit the latter model: their distribution is mainly re- Laoshidan section, it shows a dominance by D. basiovalis. Rasmussen lated to depth and distance from shore (Rasmussen, 1998). Based on and Stouge (1995) proposed that the Drepanoistodus biofacies is in- this knowledge, quantitative analyses were frequently used to discrim- dicative of open marine, subtidal environment and is deeper than that inate the number of biofacies occurring in the succession. With ongoing of the Scalpellodus biofacies. Feltes and Albanesi (2013) and Serra and study, more and more researchers use multivariate statistical methods Albanesi (2013) discriminated the same or similar biofacies in Argentine in order to distinguish conodont biofacies and many have related changes Precordillera, and suggested that this conodont fauna was representative of biofacies to sea-level fluctuations (e.g., Sweet and Bergström, 1984; Ji of deep, proximal to distal slope environments. The Phragmodus and Barnes, 1994; Rasmussen and Stouge, 1995; Zhang and Barnes, biofacies, in which P. paraundatus is the dominating taxon, occurs 2002, 2004; Zhang et al., 2006; Wu et al., 2014). in a stratigraphically slightly higher position of the H. bellburnensis The Sandaokan and Zhuozishan formations of the Laoshidan section Zone. Sweet (1988) identified the Phragmodus biofacies and suggested represent – as mentioned above – environments from bank environ- that Phragmodus was a principal inhabitant of an oxygenated and well- ment to the middle part of a carbonate shelf in ascending order. This lit offshore environment which is above the colder bottom-water mass. succession provides a good setting for detailed description of the cono- Leslie and Bergström (1995) went a step further to indicate that the dont paleoecology of the mid-Darriwilian in North China. The multivar- representatives of Phragmodus in the Middle Ordovician lived in deeper iate analyses of the present study employ the method introduced by Wu subtidal environment. The genera Protopanderodus, Ansella,and et al. (2014). Samples comprising few (b10 specimens) and very rare to Histiodella are also fairly common throughout the interval of the rare taxa (b3% occurrences) were excluded from the analyses, while Drepanoistodus and Phragmodus biofacies. The presence of these ac- low-diversity samples were retained. With these considerations, the companied deep-water taxa further supports a deep-water setting of the following analyses are based on 12 samples and 9 genera representing two biofacies (e.g., Feltes and Albanesi, 2013; Serra and Albanesi, 2013; in total 618 specimens (Table 2). The PAST program (Hammer et al., Serra et al., 2015). According to the DCA, the first axis shows a 2001) was used for the execution of the multivariate analyses. The trend from the Drepanoistodus to Phragmodus biofacies interpreted as Q-mode cluster analysis indicates that four conodont biofacies can be representing increasing distance from the coast. In light of the 60 X. Jing et al. / Marine Micropaleontology 125 (2016) 51–65

Table 2 Distribution of conodont genera and number of conodont elements used for cluster and DCA analysis.

Samples L-3-3 L-7-1 L-9-1 L-10-1 L-12-1 L-13–2 L-14-1 L-16–1 L-16–2 L-18–1 L-18-3 L-19-2 Total

Genus

Ansella 10010001618 6033 Drepanoistodus 53110009 1 133137 Histiodella 10000011201618755 Panderodus 30423128 0 65143105 Parapanderodus 01020104 1 6 6122 Paroistodus 01010109 1 197039 Phragmodus 0 1 0 0 0 0 0 0 236 8 0 10 255 Protopanderodus 00000002 7 8 14637 Scalpellodus 0422 135 4 0 0 2 3 1 36 Total 10 10 7 9 16 8 7 60 247 145 71 29 619 sedimentological evidence, the strata yielding Drepanoistodus and margin of the North China Craton were investigated. The relatively Phragmodus biofacies are normally characterized by thin-bedded marl regular occurrences of several morphologically advanced species of and bioturbated limestone. Here, the Drepanoistodus and Phragmodus Histiodella allow recognition of the Histiodella-based zones in the biofacies are interpreted as representing respectively the mid and distal Laoshidan section, i.e., the H.cf.holodentata Zone, the H. kristinae subtidal environments. Zone and the H. bellburnensis Zone, in ascending order. Among Environmental and sea-level changes can be evaluated on the basis these, the H.cf.holodentata Zone occupies the stratigraphic inter- of the shifts of conodont biofacies from the Laoshidan section (Fig. 2). val from the upper part of the Sandaokan Formation to the base The two replacements of the Panderodus biofacies by the Scalpellodus portion of the Zhuozishan Formation, the H. kristinae and H. biofacies in the lower and middle parts of the H. kristinae Zone are bellburnensis Zones cover the main part of the Zhuozishan Forma- interpreted as reflecting two individual transgressions. The turnover tion. This conodont biostratigraphic succession can be directly cor- from the Scalpellodus biofacies to the Drepanoistodus biofacies, and fur- related with the conodont zonations recently established in ther to the Phragmodus biofacies at the basal part of the H. bellburnensis western Newfoundland and Tarim, and can be well compared Zone manifests a prominent transgression. Wang et al. (2014a) also dis- with the classic conodont zones of Baltoscandia, Yangtze and tinguished these transgressions (Fig. 5) according to the analysis of sed- Argentina. However, the same stratigraphic interval on the North imentary facies on the western margin of the North China Craton. A China Platform is restricted to the lower part of the Machiakou For- significant lowering of sea–level which is represented by the change mation, which is barren of conodonts. of conodont biofacies from the Phragmodus biofacies to the Panderodus Using multivariate techniques, four conodont biofacies are recog- biofacies in the lower-mid part of the H. bellburnensis Zone was not re- nized in the study section, i.e., Panderodus, Scalpellodus, Drepanoistodus ported by Wang et al. (2014a). Curiously, this Panderodus biofacies level and Phragmodus biofacies. Three transgressions are interpreted from is made up by thin-bedded micritic limestone that was deposited in changes of conodont biofacies, but the disharmonious shallow water deep-water environment and contains relatively abundant Phragmodus, Panderodus biofacies occurred in the H. bellburnensis Zone is attributed Protopanderodus, Drepanoistodus and Ansella specimens (Table 2). Such to the immigration of shallow water conodonts rather than a regression. a profound disagreement between biofacies and sedimentary facies is Therefore, it is ingenuous to study sea-level changes only through the almost certainly due to the immigration of shallow water conodonts conodont biofacies established on a statistical basis, the cross identifica- (mainly Panderodus species) from the eastern North China Platform. tions with other water-depth sensitive evidences are necessary. If excluding the effect of allochthonous conodonts (e.g., Panderodus spec- 7. Conclusions imens in sample L-18–1) on the multivariate analyses, the transgres- sive–regressive patterns demonstrated by the conodont biofacies The conodont biostratigraphy and biofacies of the Sandaokan compare closely to the published sea-level curves for the western mar- and Zhuozishan formations of the Laoshidan section in the western gin of the North China Craton.

Fig. 4. (A) Q-mode cluster analysis and (B) DCA (Detrended Correspondence Analysis) of the conodont fauna from the Sandaokan and Zhuozishan Formations in the Laoshidan section. Q-mode cluster analysis using PAST program based on the Morisita's coefficient; In the DCA diagram the dots represent samples and triangles indicate the genera. X. Jing et al. / Marine Micropaleontology 125 (2016) 51–65 61

Fig. 5. Sea-level changes based on the distribution of conodont biofacies in the Laoshidan section, compared with the sea-level curve proposed by Wang et al. (2014a).

8. Systematic paleontology Fig. 6. 1, Ansella crassa Bauer, 1994; Sb, lateral view, from L-3-3, CUGB-jxch501. Conodonts obtained from our samples are mainly identifiable with 2–7, Ansella jemtlandica (Löfgren, 1978); 2, Pa, inner lateral view, from L-16–1, species that are well known and have been adequately described in CUGB-jxch562; 3, Pb, lateral view, from L-16–1, CUGB-jxch564; 4, Sa, lateral – – – previous publications, or the material at hand is sparse, thus does not view, from L-16 1, CUGB-jxch559; 5 6, Sb, lateral view, from L-16 1, CUGB- jxch560, CUGB-jxch561; 7, Sc, inner lateral view, from L-18–1, CUGB-jxch596. add substantial news to the current understanding of the species. 8, Ansella jemtlandica var.; M, lateral view, from L-18-3, CUGB-jxch216. Therefore, only one known species and three taxa under open no- 9–13, Ansella longicuspica Zhang, 1998; 9, Pb, lateral view, from L-10-1, CUGB- menclature are included in the following descriptions of this report. jxch528; 10, M, outer lateral view, from L-18–1, CUGB-jxch211; 11, Sa, lateral All specimens of this study are deposited in the School of Earth view, from L-18–1, CUGB-jxch595; 12, Sb, inner lateral view, from L-18-3, CUGB-jxch611; 13, Sc, inner lateral view, from L-18–1, CUGB-jxch605. Sciences and Resources, China University of Geosciences (Beijing), – fi 14 16, Aurilobodus leptosomatus An, 1983; 14, t, posterior view, from L-14-1, CUGB- with the pre x CUGB. Collection numbers of all illustrations shown jxch550; 15, s', posterior view, from L-9-1 CUGB-jxch519; 16, t’, posterior in Figs. 6 to 8 are prefixed CUGB-jxch. view, from L-11-3, CUGB-jxch537. Genus Phragmodus BRANSON and MEHL, 1933. 17, Baltoniodus medius (Dzik, 1976); S, lateral view, from L-5-3, CUGB-jxch505. Type species. Phragmodus primus BRANSON and MEHL, 1933. 18–19, Cornuodus longibasis (Lindström, 1955); 18, Sa, lateral view, from L-10-1, CUGB-jxch529; 19, Sb, lateral view, from L-9-1, CUGB-jxch521. Phragmodus paraundatus WANG and LUO, 1984. 20, Cornuodus sp.; Sa, lateral view, from L-7-1, CUGB-jxch512. Fig. 8.12–8.20. 21–22, Drepanodus reclinatus (Lindström, 1955); 21, Sc, lateral view, from L-6-2, Pa element. CUGB-jxch510; 22, Sb, lateral view, from L-18–1, CUGB-jxch608. 1984 Phragmodus? sp. A Stouge, p.83, pl.16, figs.16 23–26, Drepanoistodus basiovalis (Sergeeva, 1963); 23–24,P,innerlateralview,23 1984 Cordylodus cf. prion Wang and Luo, p.256, pl.9, figs.10 from L-10-2 CUGB-jxch188, 24 from L-5-2 CUGB-jxch504; 25, Sb, lateral view, from L-16–1, CUGB-jxch575; 26, Sc, inner lateral view, from L-18–1, Pb element. CUGB-jxch207; 1984 Phragmodus? sp. A Stouge, p.83, pl.16, figs.18 27–29, Drepanoistodus costatus (Abaimova, 1971); 27–28, Sa, lateral view, 27 from 1984 Cordylodiform element Wang and Luo, pl.9, figs.9,20 L-3-1 CUGB-jxch500, 28 from L-10-1 CUGB-jxch187; 29, Sb, lateral view, Melement. from L-6-2, CUGB-jxch511. 30–31,33, Drepanoistodus tablepointensis Stouge, 1984; 30, P, inner lateral view, 1984 Phragmodus? sp. A Stouge, p.83, pl.16, figs.19 from L-19–1, CUGB-jxch614; 31, Sa, lateral view, from L-16–1, CUGB- Sa element. jxch551; 33, M, lateral view, from L-16–1 CUGB-jxch196. 1984 Phragmodus paraundatus Wang and Luo, p.273, pl.9, figs.17 32, Triangulodus maocaopus Zhang, 1998; M, lateral view, from L-18–1CUGB- Sb element. jxch206. 1984 Phragmodus paraundatus Wang and Luo, p.273, pl.9, figs.15–16 34, Drepanoistodus suberectus (Branson and Mehl, 1933); M, lateral view, from L-17–1, CUGB-jxch203. Sc element. 35, Dzikodus sp.; P, oral view, from L-18-3, CUGB-jxch213. 1984 Phragmodus paraundatus Wang and Luo, p.273, pl.9, figs.18 Scale bars are 50 μm. 1984 Phragmodus? sp. A Stouge, p.83, pl.16, figs.17 Remarks. —Phragmodus paraundatus was originally erected as a form species based on the S elements from the Zhuozishan and Klimoli for- been fully described and illustrated separately by Wang and Luo (1984) mations of the study area (Wang and Luo, 1984, pl.9, Figs 15–18). This and Stouge (1984).TheCordylodus cf. prion,Cordylodiformelementand species is interpreted herein as a seximembrate apparatus including Phragmodus paraundatus specimens of Wang and Luo (1984) corre- ramiform P (pastinate Pa and Pb), geniculate coniform M and ramiform spond to the Pa, Pb and S elements of this species, respectively; the S (alate Sa, tertiopedate Sb, bipennate Sc) elements. The elements have ozarkodiniform, cordylodontiform and oistodontiform elements of 62 X. Jing et al. / Marine Micropaleontology 125 (2016) 51–65

Fig. 7. 1, Histiodella cf. holodentata Ethington and Clark, 1982; Pa, lateral view, from L-3-3, Fig. 8. 1–2, Parapanderodus striatus (Graves and Ellison, 1941); slender el., 38, lateral view, CUGB-jxch502. from L-18-3, CUGB-jxch214; 39, posterolateral view, from L-17–1, CUGB- 2–7, Histiodella kristinae Stouge, 1984; Pa, lateral view, 2 from L-6-2 CUGB-jxch182, jxch592. 3–4fromL-16–1 CUGB-jxch566 CUGB-jxch567, 5–6fromL-18–1CUGB- 3–4, Paroistodus originalis (Sergeeva, 1963); 3, Sc, lateral view, from L-18–1, CUGB- jxch602 CUGB-jxch597, 7 from L-18-3 CUGB-jxch613. jxch210; 4, M, lateral view, from L-16–1CUGB-jxch573. 8, Histiodella wuhaiensis Wang et al., 2013b; Pa, lateral view, from L-16–1, CUGB- 5–9, Paroistodus horridus (Barnes and Poplawski, 1973); 5, Sa, lateral view, from L- jxch568. 18–1, CUGB-jxch601; 6, Sb, lateral view, from L-16–1, CUGB-jxch556; 7, Sc, lat- 9–10, Histiodella bellburnensis Stouge, 1984; Pa, lateral view, from L-16–1, CUGB- eral view, from L-16–1, CUGB-jxch558; 8–9, M, lateral view, 8 from L-18–1 jxch570, CUGB-jxch195. CUGB-jxch205, 9 from L-16–1CUGB-jxch574. 11–12, Juanognathus sp.; Sb, posterolateral view, 11 from L-9-1 CUGB-jxch524, 12 10, Periodon cf. zgierzensis (Dzik, 1976); M, lateral view, from L-16–2, CUGB- from L-12-1 CUGB-jxch545. jxch201. 13–15, Loxodus dissectus An et al., 1983; lateral view, 13 from L-12-1 CUGB-jxch539, 11, Phragmodus sp.; Sb, lateral view, from L-7-1, CUGB-jxch514. 14 from L-9-1 CUGB-jxch520, 15 from L-12-1 CUGB-jxch538. 12–20, Phragmodus paraundatus Wang and Luo, 1984;12–13, Pb, inner lateral view, 16–17, Nealeodus aff. martinpointensis Stouge, 2012; 16, Pa, inner lateral view, from from L-16–2, CUGB-jxch584 CUGB-jxch583; 14–15, M, inner lateral view, L-18–1, CUGB-jxch593; 17, Sb, inner lateral view, from L-11-2, CUGB- from L-16–2, CUGB-jxch586 CUGB-jxch585; 16–17, Sa, lateral view, from jxch533. L-16–2, CUGB-jxch582 CUGB-jxch580; 18–19, Sb, lateral view, from L-16– 18, Panderodus cf. nogamii (Lee, 1975); lateral view, from L-18–1, CUGB-jxch212. 2, CUGB-jxch578 CUGB-jxch579; 20, Sc, lateral view, from L-16–2, CUGB- 19–20, Panderodus sulcatus (Fåhræus, 1966); falciform, lateral view, 19 from jxch581. L-18–1, CUGB-jxch606, 20 from L-11-3, CUGB-jxch536. 21–22, Protopanderodus cf. varicostatus (Sweet and Bergström, 1962); Pb, lateral 21–26, Panderodus nogamii (Lee, 1975); 21, Pa, lateral view, from L-18–1, CUGB- view, 21 from L-16–2 CUGB-jxch588, 22 from L-16–2CUGB-jxch587. jxch204; 22–23, Pb, lateral view, 22 from L-10-1 CUGB-jxch526, 23 from 23, –24 Protopanderodus graeai (Hamar, 1966); Sb, lateral view, from L-18–1, CUGB- L-18–1 CUGB-jxch604; 24, M, lateral view, from L-10-1, CUGB-jxch599; jxch208 CUGB-jxch609. 25, Sa, lateral view, from L-13–2, CUGB-jxch548; 26, Sb, lateral view, from 25–32, Scalpellodus pointensis Stouge, 1984; 25, element 1, posterolateral view, from L-9-1, CUGB-jxch522. L-11-3, CUGB-jxch535; 26, element 1, lateral view, from L-12-1, CUGB- 29, Parapaltodus simplicissimus Stouge, 1984; Drepanodiform, lateral view, from jxch191; 27, element 2, posterolateral view, from L-7-1, CUGB-jxch183; L-13–2, CUGB-jxch193. 28, element 2, posterolateral view, from L-12-1, CUGB-jxch189; 29, element 27–28, 30–31, Parapanderodus arcuatus Stouge, 1984;27–28, symmetrical bicostate 2, posterior view, from L-6-2, CUGB-jxch508; 30, element 2, posterior view, el., posterolateral view, 27 from L-17–1, CUGB-jxch591, 28 from L-10-1, from L-13–2, CUGB-jxch547; 31–32, element 2, posterior view, from L-12-1, CUGB-jxch530; 30–31, short asymmetrical el., posterior view, 30 from L- CUGB-jxch541 CUGB-jxch542. 13–2 CUGB-jxch549, 31 from L-7-1 CUGB-jxch516. 33–34, Semiacontiodus cornuformis (Sergeeva, 1963); 33, Pa, posterolateral view, 32–34, Parapanderodus paracornutiformis (Ethington & Clark, 1982); 32, asymmetrical from L-10-1, CUGB-jxch531; 34, Sc, posterolateral view, from L-21-3, slender el., lateral view, from L-16–2, CUGB-jxch589; 33–34, asymmetrical CUGB-jxch618. squat el., posterior view, from L-7-1, CUGB-jxch518 CUGB-jxch517. 35–37, Tripodus laevis Bradshaw, 1969; 35, P, inner lateral view, from L-13–2, CUGB- 35, Gen. et sp. indet. A; inner lateral view, from L-18-3, CUGB-jxch217. jxch194; 36–37, Sa, posterior and lateral view, from L-16–1, CUGB-jxch572 36–37, Gen. et sp. indet. B; 36, P, inner lateral view, from L-19-2, CUGB-jxch615; 37, CUGB-jxch577. Sc, inner lateral view, from L-19-2 CUGB-jxch616. 38–40, Gen. et sp. indet. C; 38, Sa, lateral view, from L-12-1, CUGB-jxch544; 39, Sb, Scale bars are 50 μm. lateral view, from L-16–1, CUGB-jxch553; 40, Sc, inner lateral view, from L- 22-2, CUGB-jxch619. Scale bars are 50 μm. Stouge (1984) are reassigned separately to Pa, (Pb + Sc) and M elements. Based on Newfoundland material, Stouge (1984) assigned the species tentatively to the genus Phragmodus because a trichonodelliform element (Stouge, 1984, pl.16:20) with two short lateral processes was presented X. Jing et al. / Marine Micropaleontology 125 (2016) 51–65 63 in his apparatus reconstruction. However, such an element included in References the P. paraundatus apparatus is not supported by our collection, thus we prefer to exclude it from this species. In the present material, Pa element Abaimova, G.P., 1971. New Early Ordovician conodonts from the southeastern part of the Siberian Platform. Paleontol. J. 5, 486–493. has a pointed antero-basal corner which is different from the rounded Agematsu, S., Sashida, K., Salyapongse, S., Sardsud, A., 2006. Ordovician conodonts from antero-basal corner of Pb element, oistodontiform M element has a sinu- the Thong Pha Phum area, western Thailand. J. Asian Earth Sci. 26, 49–60. ous aboral outline, S elements which form a symmetry-transition series Agematsu, S., Sashida, K., Ibrahim, A.B., 2008a. Biostratigraphy and paleobiogeography of Middle and Late Ordovician conodonts from the Langkawi Islands, northwestern have an upwardly arched aboral margin in lateral view. The denticles of peninsular Malaysia. J. Paleontol. 82, 957–973. the S elements have an increasing tilt posteriorly from the cusp toward Agematsu, S., Sashida, K., Sardsud, A., 2008b. Reinterpretation of Early and Middle Ordo- the largest denticle on the posterior process, the largest denticle is vician conodonts from the Thong Pha Phum area, western Thailand, in the context of – nearly the same size as or a little bigger than the cusp, small denticles be- new material from western and northern Thailand. Paleontol. Res. 12, 181 194. Albanesi, G.L., Ortega, G., 2002. Advances on conodont-graptolite biostratigraphy of the hind the largest denticle are vertical to the process. The present apparatus Ordovician System of Argentina. In: Aceñolaza, F. (Ed.), Aspects of the Ordovician Sys- reconstruction of this species is consistent with the apparatus model of tem in Argentina. INSUGEO, Série Correlación Geológica, pp. 143–166. the genus Phragmodus summarized by Sweet (1981) and Leslie and Albanesi, G.L., Bergström, S.M., Schmitz, B., Serra, F., Feltes, N.A., Voldman, G.G., Ortega, G., 2013. Darriwilian (Middle Ordovician) δ C13carb chemostratigraphy in the Bergström (1995). Precordillera of Argentina: documentation of the middle Darriwilian Isotope Carbon Material. —254 specimens from 3 samples of the Zhuozishan Forma- Excursion (MDICE) and its use for intercontinental correlation. Palaeogeogr. – tion (see Table 1). Palaeoclimatol. Palaeoecol. 389, 48 63. Aldridge, R.J., 1976. Comparison of macrofossil communities and conodont distribution in Genus et species indet. A. the British Silurian. In: Barnes, C. (Ed.), Conodont Paleoecology, Special Paper. Geo- Fig. 7.35. logical Association of Canada, pp. 92–104. Description. —Genus et species indet. A is represented by a robust, Aldridge, R.J., Jeppsson, L., 1984. Ecological specialists among Silurian conodonts. Palaeontology 32, 141–149. asymmetrical and incomplete cone; cusp is proclined, outer lateral An, T.X., Zheng, Z.C., 1990. The Conodonts of the Marginal Areas around the Ordos Basin, face gently convex, a broad carina developed in the inner lateral face North China. Science Press, Beijing, pp. 1–199. and throughout the cone; keeled anterior edge is smooth, but posterior An, T.X., Zhang, F., Xiang, W.D., Zhang, Y.Q., Xu, W.H., Zhang, H.J., Jiang, D.B., Yang, C.S., Lin, L.D., Cui, Z.T., Yang, X.C., 1983. The Conodonts of North China and of the Adjacent Re- edge is serrate in the middle part, denticles are close together, fused ba- gions. Science Press, Beijing, pp. 1–233. sally and free apically, and incline toward the cusp at c. 45 degrees. Barnes, C.R., Fåhraeus, L.E., 1975. Provinces, communities, and the proposed nektobenthic Material. —1 specimen from the Zhuozishan Formation (see Table 1). habit of Ordovician conodontophorids. Lethaia 8, 133–149. Genus et species indet. B. Barnes, C.R., Poplawski, M.S., 1973. Lower and Middle Ordovician conodonts from the Mystic Formation, Quebec, Canada. J. Paleontol. 47, 760–790. Fig. 7.36–7.37. Bauer, J.A., 1994. Conodonts from the Bromide Formation (Middle Ordovician), South- Description. —Two elements of this taxon are obtained from our Central Oklahoma. J. Paleontol. 68, 358–376. samples and assigned to P and Sc elements, respectively, both of them Bergström, S.M., 2007. The Ordovician conodont biostratigraphy in the Siljan region, south-central Sweden: a brief review of an international reference standard, in: are robust and with an angular junction between cusp and upper mar- Ebbestad, J.O.R., Wickström, L.M., Högström, A.E.S. (Eds.), pp. 26–41. gin of the base, basal cavity is wide and occupies almost the whole Bergström, S.M., Chen, X., Gutiérrez-Marco, J.C., Dronov, A., 2009. The new chrono- fi base. P element has a suberect keeled cusp and a wide base posteriorly stratigraphic classi cation of the Ordovician System and its relations to major region- al series and stages and to delta C-13 chemostratigraphy. Lethaia 42, 97–107. extended with keeled upper margin, a lower triangular base is slightly Bradshaw, L.E., 1969. Conodonts from the Fort Peña Formation (Middle Ordovician), Mar- flared on the inner side and strongly flared on the outer side, a thick- athon Basin, Texas. J. Paleontol. 42, 1137–1168. ened rim develops above the aboral margin. Sc element has a large Branson, E.B., Mehl, M.G., 1933. Conodont studies. Univ. Miss. Stud. 8, 1–349. Cao, J.Z., Feng, Q., Zhao, W., Zhou, S.C., Wang, Q.Y., Liu, Z., Lu, Y.J., Li, Y.L., 2011. Sequence triangular base which is nearly equilateral and has a keeled upper stratigraphy of Ordovician strata in the South Part of Ordos area. Acta Sedimentol. margin; cusp proclined and keeled, bears a broad carina on the Sin. 29, 286–292. inner side. Chen, J.Y., 1976. Advances in the Ordovician stratigraphy of North China with a brief de- — scription of nautiloid fossils. Acta Palaeontol. Sin. 15, 55–74. Material. 6 specimens from 2 samples of the Zhuozishan Formation Chen, J.Y., Zhou, Z.Y., Lin, Y.K., Yang, X.C., Zou, X.P., Wang, Z.H., Luo, K.Q., Yao, B.Q., Shen, H., (see Table 1). 1984. Ordovician biostratigraphy of Western Ordos. Bull. Nanjing Inst. Geol. Genus et species indet. C. Palaeontol., Acad. Sin. 20, 1–31. Fig. 8.38–8.40. Chen, X., Zhang, Y.D., Bergström, S.M., Xu, H.G., 2006. Upper Darriwilian graptolite and co- nodont zonation in the global stratotype section of the Darriwilian stage (Ordovician) Description. —A series of simple cones display a symmetry-transition at Huangnitang, Changshan, Zhejiang, China. Palaeoworld 15, 150–170. series from laterally compressed symmetrical Sa element with erect Cho, D.L., Lee, S.R., Koh, H.J., Park, J.B., Armstrong, R., Choi, D.K., 2014. Late Ordovician vol- cusp to slightly asymmetrical Sb element with weakly recurved cusp to canism in Korea constrains the timing for breakup of Sino-Korean Craton from Gond- wana. J. Asian Earth Sci. 96, 279–286. evidently asymmetrical Sc element with recurved and twisted cusp. All DE Jong, K., Xiao, W.J., Windley, B.F., Masago, H., Lo, C.H., 2006. Ordovician Ar-40/Ar-39 the S elements show a keeled cusp and a distinctively recessive basal phengite ages from the blueschist-facies Ondor Sum subduction–accretion complex margin. (Inner Mongolia) and implications for the Early Paleozoic history of continental – — blocks in China and adjacent areas. Am. J. Sci. 306, 799 845. Material. 7 specimens from 3 samples of the Zhuozishan Formation Du, P.D., Zhao, Z.X., Huang, Z.B., Tan, Z.J., Wang, C., Yang, Z.L., Zhang, G.Z., Xiao, J.N., 2005. (see Table 1). Discussion on four conodont species of Histiodella from Tarim Basin and their strati- graphic implication. Acta Microbiol. Sin. 22, 357–369. Dzik, J., 1976. Remarks on the evolution of Ordovician conodonts. Acta Palaeontol. Pol. 21, Acknowledgements 395–455. Dzik, J., 1994. Conodonts of the Mójcza Limestone. Palaeontol. Pol. 53, 43–128. This study has been supported by the Grants from the “973– Ethington, R.L., Clark, D.L., 1982. Lower and Middle Ordovician conodonts from the Ibex ” area, western Millard County, Utah. Brigham Young Univ. Geol. Stud. 28, 1–160. Program project of China (2011CB403001), National Natural Science Fåhræus, L.E., 1966. Lower Viruan (Middle Ordovician) conodonts from the Gullhögen Foundation of China (41502026), and State Key Laboratory of quarry, southern central Sweden. Sver. Geol. Unders.C 601, 1–40. Biogeology and Environmental Geology, China (GBL21511). We are Feltes, N.A., Albanesi, G.L., 2013. The Periodon and Paroistodus conodont biofacies in the indebted to Svend Stouge (Copenhagen) for making valuable Lower Member of the Las Aguaditas Formation (Middle Ordovician), central Precordillera, Argentina. In: Albanesi, G.L., Ortega, G. (Eds.), Conodonts from the improvements of conodont identification and biostratigraphy, to Andes — The Third International Conodont Symposium, Mendoza, Argentina, Paleon- Rongchang Wu (Nanjing) for making helpful suggestions on multi- tological Note Pe Apa, pp. 17–23. variate techniques, and to Zhentao Wang, Qiang Fang, Xianteng Feltes, N.A., Albanesi, G.L., Bergström, S.M., 2013. Middle Darriwilian conodont zones in the uppermost San Juan Limestone and the Lower Member of the Las Aguaditas For- Song, Tingting Chuan and Lupeng Yuan from China University of mation, Central Precordillera of San Juan, Argentina. In: Albanesi, G.L., Ortega, G. Geosciences (Beijing) for assistance within sampling. Comments (Eds.), Conodonts from the Andes — the Third International Conodont Symposium, and corrections made by the two reviewers, Guillermo Albanesi Mendoza, Argentina. Paleontological Note PE APA, pp. 25–31. fi Feltes, N.A., Albanesi, G.L., Bergström, S.M., 2016. Conodont biostratigraphy and global and Svend Stouge, and Richard W. Jordan (editor) signi cantly im- correlation of the middle Darriwilian — lower Sandbian Las Aguaditas Formation, proved our manuscript and are greatly appreciated. Precordillera of San Juan, Argentina. Andean Geol. 43, 60–85. 64 X. Jing et al. / Marine Micropaleontology 125 (2016) 51–65

Feng, Z.Z., Bao, Z.D., Zhang, Y.S., 1998. Lithofacies paleography of Ordovician carbonatite Rasmussen, J.A., 1998. A reinterpretation of the conodont Atlantic Realm in the late Early formation in Ordos Basin. Geological Publishing House, Beijing, pp. 1–144. Ordovician (early Llanvirn). Acta Palaeontol. Pol. 58, 67–77. Feng, Z.Z., Peng, Y.M., Jin, Z.K., Bao, Z.D., 2004. Lithofacies paleogeography of the Cambrian Rasmussen, J.A., 2001. Conodont biostratigraphy and taxonomy of the Ordovician shelf and Ordovician in China. Petroleum Industry Press, Beijing, pp. 1–233. margin deposits in the Scandinavian Caledonides. Fossils Strata 48, 1– 180. Feng,Z.Z.,Zheng,X.J.,Bao,Z.D.,Jin,Z.K.,Wu,S.H.,He,Y.B.,Peng,Y.M.,Yang,Y.Q.,Zhang,J.Q., Rasmussen, J.A., Stouge, S., 1995. Late Arenig-Early Llanvirn conodont biofacies across the Zhang, Y.S., 2014. Quantitativelithofaciespalaeogeography.J.Palaeogeogr.3,1–34. Iapetus ocean. In: Cooper, J.D., Droser, M.L., Finney, S.C. (Eds.), Ordovician Odyssey: Finney, S.C., Bergström, S.M., Chen, X., Wang, Z., 1999. The Pingliang section, Gansu Prov- Short Papers for the Seventh International Symposium on the Ordovician System. ince, China: potential as global stratotype for the base of the Nemagraptus gracilis SEPM, Pacific Section, pp. 443–447. Biozone and the base of the global Upper Ordovician Series. Acta Univ. Carol. Geol. Seddon, G., Sweet, W.C., 1971. An ecologic model for conodonts. J. Paleontol. 45, 869–880. 43, 73–75. Sergeeva, S.P., 1963. Conodonts from the Lower Ordovician of the Leningrad region. Graves, R.W., Ellison, S.P., 1941. Ordovician conodonts of the Marathon basin, Texas. Uni- Paleontologicheskiy Zh. Akademiya Nauk SSSR 2, 93–108. versity of Missouri, School of Mines and Metallurgy, Bulletin of the Technical Series Sergeeva, S., 1974. Some new conodonts from the Ordovician deposits of Leningrad re- 14, pp. 1–26. gion. Paleontologičeskij sbornik 2, 79–84. Hamar, G., 1966. Preliminary report on conodonts from the Oslo-Asker and Ringerike dis- Serra, F., Albanesi, G.L., 2013. Paleoecology and paleobiogeography of Darriwilian tricts. Nor. Geol. Tidsskr. 46, 27–83. conodonts from the Las Chacritas Formation, central Precordillera of San Juan, Hammer, Ø., Harper, D.A.T., Ryan, P.D., 2001. PAST: paleontological statistics software Argentina. In: Albanesi, G.L., Ortega, G. (Eds.), Conodonts from the Andes — the package for education and data analysis. Palaeontol. Electron. 4 (9 pp.). Third International Conodont Symposium, Mendoza, Argentina. Paleontological Harris, A.G., Bergström, S.M., Ethington, R.L., Ross JR., R.J., 1979. Aspects of Middle and Note PE APA, pp. 103–108. Upper Ordovician conodont biostratigraphy of carbonate facies in Nevada and south- Serra, F., Albanesi, G.L., Bergström, S.M., 2013. Middle Darriwilian conodont biostra- east California and comparison with some Appalachian successions. Brigham Young tigraphy of the Las Chacritas Formation, central Precordillera of San Juan, Univ. Geol. Stud. 26, 7–33. Argentina. In: Albanesi, G.L., Ortega, G. (Eds.), Conodonts from the Andes — the Heredia, S., Peralta, S.H., Beresi, M., 2005. Darriwilian conodont biostratigraphy of the Las Third International Conodont Symposium, Mendoza, Argentina. Paleontological Chacritas Formation, Central Precordillera (San Juan Province, Argentina). Geol. Acta Note PE APA, pp. 109–116. 3, 385–394. Serra, F., Albanesi, G.L., Ortega, G., Bergström, S.M., 2015. Biostratigraphy and palaeoecol- Ji, Z.L., Barnes, C.R., 1994. Conodont paleoecology of the Lower Ordovician St-George ogy of Middle–Late Ordovician conodont and graptolite faunas of the Las Chacritas Group, Port Au Port Peninsula, Western Newfoundland. J. Paleontol. 68, 1368–1383. River section, Precordillera of San Juan, Argentina. Geol. Mag. 152, 813–829. Jing, X.C., Zhou, H.R., Wang, X.L., 2015. Ordovician (Middle Darriwilian-Earliest Sandbian) Stait, K., Druce, E.C., 1993. Conodonts from the Lower Ordovician Coolibah Formation, conodonts from the Wuhai area of Inner Mongolia, North China. J. Paleontol. 89 (in Georgina Basin, Central Australia. BMR J. Aust. Geol. Geophys. 13, 293–322. press). Stouge, S., 1984. Conodonts of the Middle Ordovician Table Head Formation, western Kuhn, T., Barnes, C., 2005. Ordovician conodonts from the Mithaka Formation (Georgina Newfoundland. Fossils Strata 16, 1–145. Basin, Australia). Regional and paleobiogeographical implications. Geol. Acta 3, Stouge, S., 2012. Middle Ordovician (late Dapingian-Darriwilian) conodonts from the Cow 317–337. Head Group and Lower Head Formation, western Newfoundland, Canada. Can. Landing, E., 1976. Early Ordovician (Arenigian) conodont and graptolite biostratigraphy of J. Earth Sci. 49, 59–90. the Taconic allochthon, eastern New York. J. Paleontol. 50, 614–646. Stouge, S., Nielsen, A.T., 2003. An integrated biostratigraphical analysis of the Volkhov- LE Fèvre, J., Barnes, C.R., Tixier, M., 1976. Paleoecology of Late Ordovician and Early Siluri- Kunda (Lower Ordovician) succession at Fagelsang, Scania, Sweden. B Geol Soc an conodontophorids, Hudson Bay Basin. In: Barnes, C.R. (Ed.), Geological Association Denmark 50, 75–94. of Canada, Special Paper, pp. 69–89. Stouge, S., Du, P.D., Zhao, Z.X., 2011. Middle Ordovician (Darriwilian) global conodont zo- Lee, H.Y., 1975. Conodonten aus dem unteren und mittleren Ordovizium von Nordkorea. nation based on the Dawangou and Saergan formations of the Western Tarim Region, Palaeontogr. Abt. A 150, 161–186. Xinjiang Province, China. In: Gutiérrez-Marco, J.C., Rábano, I., Garcia-Bellido, D. (Eds.), Leslie, S.A., Bergström, S.M., 1995. Elements morphology and toxonomic relationships of Ordovician of the WorldCuadernos Del Museo Geominero Vol. 14. Instituto Geológico the Ordovician conodonts Pharagmodus primus Branson and Mehl, 1933, the type y Minero de España, Madrid, pp. 581–586. species of Phragmodus Branson and Mehl, 1993, and Phragmodus undatus Branson Sweet, W.C., 1981. Genera Phragmodus Branson and Mehl, 1933 and Plectodina and Mehl, 1933. J. Paleontol. 69, 967–974. Stauffer, 1935. In: Ziegler, W. (Ed.), Catalogue of Conodonts. Schweizerbart'sche Lin, C.S., Yang, Q., Li, S.T., Li, Z., 1991. Sedimentary characters of the Early Paleozoic deep Verlagsbuchhandlung, Stuttgart, pp. 245–290. water gravity flow systems and basin filling style in the Helan Aulacogen, Northwest Sweet, W.C., 1988. The Conodonta: Morphology, Taxonomy, Paleoecology, and Evolution- China. Geosciences 5, 252–263. ary History of a Long-Extinct Animal Phylum. Clarendon Press, Oxford, pp. 1–212. Lindström, M., 1955. Conodonts from the lowermost Ordovician strata of south-central Sweet, W.C., Bergström, S.M., 1962. Conodonts from the Pratt Ferry Formation (Middle Sweden. GFF 76, 517–604. Ordovician) of Alabama. J. Paleontol. 36, 1214–1252. Löfgren, A., 1978. Arenigian and Llanvirnian conodonts from Jämtland, northern Sweden. Sweet, W.C., Bergström, S.M., 1984. Conodont provinces and biofacies of the Late Ordovi- Fossils Strata 13, 1–129. cian. In: Clark, D.L. (Ed.), Conodont Biofacies and Provincialism. Special Paper of the Löfgren, A., 2004. The conodont fauna in the Middle Ordovician Eoplacognathus Geological Society of America, pp. 69–88. pseudoplanus Zone of Baltoscandia. Geol. Mag. 141, 505–524. Wang, C.Y., 1993. Conodonts of the Lower Yangtze Valley-An Index to Biostratigraphy and Löfgren, A., Zhang, J.H., 2003. Element association and morphology in some middle Ordo- Organic Metamorphic Maturity. Science Press, Beijing, pp. 1–326. vician platform-equipped conodonts. J. Paleontol. 77, 721–737. Wang, Z.H., Luo, K.Q., 1984. Late Cambrian and Ordovician conodonts from the marginal Lu, Y.H., 1954. Strata issues of the Cambrian and Ordovician from Northwest China. Acta areas of the Ordos Platform, China. Bull. Nanjing Inst. Geol. Palaeontol. Acad. Sin. 8, Geol. Sin. 34, 311–318. 239–304. Maletz, J., 2009. Holmograptus spinosus and the Middle Ordovician (Darriwilian) grapto- Wang, Z.H., Zhou, T.R., 1998. Ordovician conodonts from western and northeastern Tarim lite biostratigraphy at Les Mechins (Quebec, Canada). Can. J. Earth Sci. 46, 739–755. and their significance. Acta Palaeontol. Sin. 37, 173–193. Mellgren, J.I.S., Eriksson, M.E., 2010. Untangling a Darriwilian (Middle Ordovician) Wang, Z.H., Bergström, S.M., Lane, H.R., 1996. Conodont provinces and biostratigraphy in palaeoecological event in Baltoscandia: conodont faunal changes across the 'Täljsten' Ordovician of China. Acta Palaeontol. Sin. 35, 26–59. interval. Trans. R. Soc. Edinb. Earth Environ. Sci. 100, 353–370. Wang, Z.H., Bergström, S.M., Zhen, Y.Y., Chen, X., Zhang, Y.D., 2013a. On the integration of Metcalfe, I., 1996. Gondwanaland dispersion, Asian accretion and evolution of eastern Te- Ordovician conodont and graptolite biostratigraphy: new examples from Gansu and thys. Aust. J. Earth Sci. 43, 605–623. Inner Mongolia in China. Alcheringa 37, 510–528. Metcalfe, I., 1998. Palaeozoic and Mesozoic geological evolution of the SE Asian region: Wang, Z.H., Bergström, S.M., Zhen, Y.Y., Zhang, Y.D., Wu, R.C., Chen, Q., 2013b. Ordovician multidisciplinary constraints and implications for biogeography. In: Hall, R., conodonts from Dashimen, Wuhai in Inner Mongolia and the significance of the dis- Holloway, J.D. (Eds.), Biogeography and Geological Evolution of SE Asia. Backhuys covery of the Histiodella fauna. Acta Microbiol Sin. 30, 323–343. Publishers, Amsterdam, pp. 25–41. Wang, Y., Yu, H., Zeng, J.M., 2014a. Carbon and Oxygen istope stratigraphy of Furongian- Metcalfe, I., 2006. Paleozoic and Mesozoic tectonic evolution and palaeogeography of East middle Ordovician, Qinglongshan of Ningxia. J. Northwest Univ. Nat. Sci. Ed. 44, Asian crustal fragments: the Korean Peninsula in context. Gondwana Res. 9, 24–46. 264–271. Mu, E.Z., 1959. Strata Containing Graptolites of China. Geological Publishing House, Bei- Wang, Z.H., Bergström, S.M., Zhen, Y.Y., Zhang, Y.D., Wu, R.C., 2014b. A revision of the jing, pp. 1–75. Darriwilian biostratigraphic conodont zonation in Tangshan, Hebei Province based Müller, K.J., 1962. Taxonomy, evolution, and ecology of conodonts. In: Hass, W.H., on new conodont collections. Acta Palaeontol. Sin. 53, 1–15. Häntzschel, W., Fisher, D.W. (Eds.), Treatise on Invertebrate Paleontology, Part W: Watson, S.T., 1988. Ordovician conodonts from the Canning Basin (W. Australia). Miscellanea. Geological Society of America and University of Kansas Press, Boulder, Palaeontographica 203, 91–147. Colorado. and Lawrence, Kansas, pp. 83–91. Wu, R.C., Stouge, S., Percival, I.G., Zhan, R.B., 2014. Early-Middle Ordovician conodont Myrow, P.M., Chen, J.T., Snyder, Z., Leslie, S., Fike, D.A., Fanning, C.M., Yuan, J.L., Tang, P., biofacies on the Yangtze Platform margin, South China: applications to 2015. Depositional history, tectonics, and provenance of the Cambrian–Ordovician palaeoenvironment and sea-level changes. J. Asian Earth Sci. 96, 194–204. boundary interval in the western margin of the North China block. Geol. Soc. Am. Yang, Y.T., Li, W., Ma, L., 2005. Tectonic and stratigraphic controls of hydrocarbon systems in Bull. 127, 1174–1193. the Ordos basin: a multicycle cratonic basin in Central China. AAPG Bull. 89, 255–269. Ni, S.Z., 1981. Discussion on some problems of Ordovician stratigraphy by means of Zhang, R.D., 1959. The cephalopod fossils of Lower Ordovician from Zhuozishan area, conodonts in eastern part of Yangtze Gorges Region, Selected papers on the 1st Con- Yikezhao Prefecture, Inner Mongolia, China. Acta Palaeontol. Sin. 7, 259–271. vention of Micropalaeontological Society of China. Science Press, Beijing, Zhang, W.T., 1962. The Ordovician in China. Science Press, Beijing, pp. 1–62. pp. 127–134. Zhang, J.H., 1998. Conodonts from the Guniutan Formation (Llanvirnian) in Hubei and Nowlan, G.S., Thurlow, J.G., 1984. Middle Ordovician conodonts from the Buchans Group, Hunan provinces, south-central China. Stockh. Contrib. Geol. 46, 1–161. central Newfoundland, and their significance for regional stratigraphy of the central Zhang, S.X., Barnes, C.R., 2002. Paleoecology of Llandovery conodonts, Anticosti Island, Volcanic Belt. Can. J. Earth Sci. 21, 284–296. Quebec. Palaeogeogra. Palaeoclimatol. Palaeoecol. 180, 33–55. X. Jing et al. / Marine Micropaleontology 125 (2016) 51–65 65

Zhang, S.X., Barnes, C.R., 2004. Arenigian (Early Ordovician) sea-level history and the re- Zhen, Y.Y., Wang, Z.H., Zhang, Y.D., Bergström, S.M., Percival, I.G., Cheng, J.F., 2011. Middle sponse of conodont communities, western Newfoundland. Can. J. Earth Sci. 41, to late Ordovician (Darriwilian-Sandbian) conodonts from the Dawangou section, 843–865. Kalpin area of the Tarim Basin, Northwestern China. Rec. Aust. Mus.63,203–266. Zhang, S.X., Barnes, C.R., Jowett, D.M.S., 2006. The paradox of the global standard Zhen, Y.Y., Zhang, Y.D., Wang, Z.H., Percival, I.G., 2015. Huaiyuan Epeirogeny—Shaping Late Ordovician-Early Silurian sea level curve: evidence from conodont community Ordovician Stratigraphy and Sedimentation on the North China Platform. Palaeogeogr. analysis from both Canadian Arctic and Appalachian margins. Palaeogeogr. Palaeoclimatol. Palaeoecol. (in press). Palaeoclimatol. Palaeoecol. 236, 246–271. Zheng, Y.F., Xiao, W.J., Zhao, G.C., 2013. Introduction to tectonics of China. Gondwana Res. Zhao, G.C., Zhai, M.G., 2013. Lithotectonic elements of Precambrian basement in the North 23, 1189–1206. China Craton: review and tectonic implications. Gondwana Res. 23, 1207–1240. Zhu, R.X., Yang, J.H., Wu, F.Y., 2012. Timing of destruction of the North China Craton. Lithos Zhao, Z.X., Zhang, G.Z., Xiao, J.N., 2000. Palaeozoic Strata and Conodonts in Xinjiang. Petro- 149, 51–60. leum Industry Press, Beijing, pp. 1–340.