Upper Ordovician), Zhuzhai, South China

Alcheringa: An Australasian Journal of Palaeontology

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Morphometrics and palaeoecology of the coral Agetolites from the Xiazhen Formation (Upper Ordovician), Zhuzhai, South China

Ning Sun, Robert J. Elias, Suk-Joo Choh, Dong-Chan Lee, Xun-Lian Wang & Dong-Jin Lee

To cite this article: Ning Sun, Robert J. Elias, Suk-Joo Choh, Dong-Chan Lee, Xun-Lian Wang & Dong-Jin Lee (2016) Morphometrics and palaeoecology of the coral Agetolites from the Xiazhen Formation (Upper Ordovician), Zhuzhai, South China, Alcheringa: An Australasian Journal of Palaeontology, 40:2, 251-274, DOI: 10.1080/03115518.2016.1111071

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Published online: 01 Feb 2016.

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Download by: [Shanghai Jiaotong University] Date: 17 October 2016, At: 01:28 Morphometrics and palaeoecology of the coral Agetolites from the Xiazhen Formation (Upper Ordovician), Zhuzhai, South China

NING SUN, ROBERT J. ELIAS, SUK-JOO CHOH, DONG-CHAN LEE, XUN-LIAN WANG and DONG-JIN LEE

SUN, N., ELIAS, R.J., CHOH, S.-J., LEE, D.-C., WANG, X.-L. & LEE, D.-J., February 2016. Morphometrics and palaeoecology of the coral Agetolites from the Xiazhen Formation (Upper Ordovician), Zhuzhai, South China. Alcheringa 40, 251–274. ISSN 0311-5518.

Agetolites is a peculiar cerioid coral possessing traits of both tabulates and rugosans. The presence of numerous mural pores has been considered by some workers to indicate a relation to tabulates, although an afﬁnity to rugosans has also been proposed based mainly on well-developed septa that alternate in length. Agetolites is by far the most common colonial coral in the Upper Ordovician Xiazhen Formation at Zhuzhai, in the JCY (Jiangshan–Changshan–Yushan) triangle region of South China. It occurs in various lithofacies representing a wide range of depositional environments. Five species are recognized and veriﬁed by cluster analysis, discriminant analysis, descriptive statistics and bivariate plots: A. yushanensis Lin, 1960, A. raritabulatus Lin, 1960, A. waicunensis (Lin & Chow, 1977), A. oculiporoides Lin, 1960 (including A. huangi Lin, 1960 as a junior synonym) and A. maxima (Lin & Chow, 1977). Agetolitids from the JCY triangle described previously under the generic name Agetolitella are herein transferred to Agetolites. In the Xiazhen Formation at Zhuzhai, A. waicunensis and A. maxima are restricted to the lower part of the formation, whereas A. yushanensis occurs in the upper part. Agetolites raritabulatus and A. oculiporoides have greater stratigraphic ranges in the lower and upper parts of the formation. The size and shape of Agetolites coralla at Zhuzhai are considered primarily to be intrinsic characteristics of the species but in some cases also seem to be related to lithofacies; large and domical coralla are dominant in calcareous mudstone facies, whereas small coralla with various forms are commonly found in reef or reef-related facies. In the latter facies, spatial competition is indicated by common occurrences of both Agetolites encrusting stromatoporoids and stromatoporoids encrusting Agetolites.

Ning Sun [[email protected]], School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, PR China; Robert J. Elias [[email protected]], Department of Geological Sciences, The University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada; Suk-Joo Choh [[email protected]], Department of Earth and Environmental Sciences, Korea University, Seoul 136-701, Korea; Dong-Chan Lee [[email protected]], Department of Earth and Environmental Sciences, Chungbuk National University, Cheongju, 361-763, Korea; Xun-Lian Wang [[email protected]], School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, PR China; Dong-Jin Lee* [[email protected]], Department of Earth and Environmental Sciences, Andong National University, Andong 760-747, Korea. *Also afﬁliated with College of Earth Science, Jilin University, Changchun 130061, PR China. Received 13.6.2015; revised 10.10.2015; accepted 19.10.2015.

Key words: Agetolites, corals, morphometric analysis, palaeoecology, systematics, Late Ordovician, South China.

AGETOLITIDS are a group of problematic Late detailed studies since Sokolov (1955) first documented Ordovician cerioid corals having features of both tabu- Agetolites. Three genera of agetolitids were recognized late and rugose corals. Several workers have considered by Hill (1981, pp. F559–F561): Agetolites, Agetolitella them to be allied with tabulates, owing to the presence Kim, 1962 and Somphopora Lindström, 1883. The of numerous and large mural pores (Sokolov 1955, Lin identification of Agetolitella in certain regions, such as 1960, Yu & Zhang 1963,Kim1966, Lin & Chow South China, is doubtful (Lin & Chow 1977, p. 144). 1977, Hill 1981, Lin et al. 1984, Lin & Huang 1986, The Silurian Somphopora is considered to be a theciid Oliver 1996, Wang 1997). An affinity with rugosans tabulate (Sokolov 1962, p. 329). Hemiagetolites Lele- has also been proposed, based mainly on septal patterns shus, 1963 was originally interpreted to be phylogeneti- and other morphological characteristics, such as an axial cally intermediate between the tabulate Paleofavosites structure of septal lobes or a columella (Kim 1974,Xu Twenhofel, 1914 and Agetolites (Leleshus 1963)butis et al. 1999). However, a recent study revealed that the now considered to be a junior synonym of Agetolites septal pattern in Agetolites Sokolov, 1955 from Zhuzhai (Hill 1981, p. F559). in South China is variable and can not be considered an Eight more genera of agetolitids have been erected indication of rugosan affinities (Sun et al. 2014). based on Chinese material, raising the potential for In spite of their systematic and phylogenetic signifi- considerable taxonomic confusion: Agetolitinus Deng & cance, agetolitids have been the subject of very few Li, 1979; Paragetolites Lin in Li & Lin, 1982; Subagetolites Li in Li & Lin, 1982; Hemiagetolitina Lin, 1986; Agetolitoides Lin, 1986; Paragetolitella Lin, © 2016 Australasian Palaeontologists http://dx.doi.org/10.1080/03115518.2016.1111071 1986; Subagetolitoides Lin, 1986; and Hemiagetolitella 252 NING SUN et al. ALCHERINGA

Lin & Huang, 1986. Morphological parameters used to other invertebrates, such as brachiopods (Zhan et al. define these genera are vague and inadequate, making 2002). Only a few preliminary investigations of corals their taxonomic validity questionable. There is a clear have been carried out in the JCY region (Lin 1960,Yu& and present need for further research to clarify the con- Zhang 1963, Lin & Chow 1977) and a comprehensive fusion in agetolitid classification. and modern systematic treatment is overdue. Fifteen spe- The type species of Agetolites, A. mirabilis Sokolov, cies of Agetolites and ten species of Agetolitella have 1955, was originally described as a tabulate coral from been reported from Upper Ordovician strata including the the ‘lower Llandoverian’ of the Chingiz Range in Sanqushan Formation (Lin 1960, Lin & Chow 1977), Kazakhstan. Kim (1966), however, speculated that the which is considered to be the seaward equivalent of the deposit from which the genus was reported by Sokolov Xiazhen Formation (Zhang et al. 2007, fig. 2.2). is Upper Ordovician. Agetolites has been reported Agetolites is by far the most common genus of colo- from localities in numerous areas: Kazakhstan nial corals within the Xiazhen Formation in the present (Sokolov 1955, Popov et al. 1999); Tajikistan and study area at Zhuzhai, at the southern end of the JCY Uzbekistan (Hill 1981); northeastern Russia (Koren & triangle (Fig. 1A, B). This genus occurs in diverse Sobolevskaya 2008); Jiangxi (Lin & Chow 1977), Inner lithofacies deposited in a wide range of depositional Mongolia (Lin et al. 1984), Ningxia and Xinjiang (Lin environments. The principal aims of this study are: (1) & Huang 1986, Wang 1997) in China; North Korea to re-evaluate morpho-taxonomic characteristics previ- (Pak 1983a, b, Kim 1990,An&Ma1993,Omet al. ously used in studies of Agetolites, and apply multivari- 1993); central New South Wales (Semeniuk 1970) and ate analytical methods for distinguishing and northern Queensland (Hill 1981, Webby et al. 2004)in characterizing species; and (2) to document and assess Australia; and Alaska (Oliver et al. 1975) and doubt- the palaeoecological distribution of Agetolites in the fully western Utah (Pandolfi 1985) in North America. Xiazhen Formation. The strata containing Agetolites were reported to be Upper Ordovician except for a location in northern Queensland, which Hill (1981, pp. F560, F561) identi- Geology and stratigraphy fied as Upper Ordovician or questionably lower Ordovician carbonate successions are well exposed near Silurian. The latter occurrence is probably Upper the border between Jiangxi and Zhejiang provinces, in Ordovician (lower Bolindian; Webby et al. 2004). the JCY triangle of southeastern China (Zhang et al. The JCY (Jiangshan–Changshan–Yushan) triangle, 2007; Fig. 1A). Numerous Upper Ordovician reef com- located on the border of Jiangxi and Zhejiang provinces plexes have been described from the shallow lagoon to in southeastern China, has long been known as the classic marginal reef of the Sanqushan Formation and its region for study of the Ordovician System in South China landward equivalent, the Xiazhen Formation (Bian & (Zhang et al. 2007; Fig. 1A). Despite the abundance of Zhou 1990,Yuet al. 1992, Webby 2002,Liet al. corals within the Upper Ordovician in this region, they 2004, Zhang et al. 2007). The shallow platform carbon- have received surprisingly little attention compared with ates of these formations grade into contemporaneous

Fig. 1. A, Map of China showing location of the South China Plate and enlargement of the JCY (Jiangshan–Changshan–Yushan) triangle region showing location of the study area at Zhuzhai (grey square) and locations of previously reported type specimens (small circles). B, Geological map of the study area and sub-sections ZU 1, ZU 2 and ZU 3 (modiﬁed after Lee et al. 2012). ALCHERINGA ORDOVICIAN CORALS FROM CHINA 253

fine-grained clastics of the Changwu Formation (Chen et al. 1987,Liet al. 2004). The Xiazhen Formation was first defined by Lu et al.(1976) and mostly studied around Tashan, where the type section of the formation is located (Chen et al. 1987, Zhan & Fu 1994, Zhan et al. 2002; Fig. 1A). The Xiazhen Formation at Zhuzhai in Jiangxi Pro- vince, from which specimens of Agetolites forming the basis of this study were collected, has recently been re- measured and described in detail by integration of lithological and palaeontological data (Lee et al. 2012; Fig. 1A, B). This study follows Lee et al.(2012), who presented a revised stratigraphy of the formation exposed at Zhuzhai. Comparison of lithological and palaeontological data of the exposures (designated therein as sub-sections ZU 1, ZU 2 and ZU 3, separated by Quaternary deposits) demonstrates that stratigraphic intervals of the sub-sections overlap (Figs 1B, 2). The exposure of the formation at Zhuzhai is about 190 m thick (Fig. 2). Four informal members are recognized within the formation: the lower limestone member, lower shale member, middle mixed-lithology member and upper shale member (Lee et al. 2012; Figs 1B, 2). Corals were not found in the lower shale member. All of sub-section ZU 3 correlates with the upper part of ZU 1, and identical species of Agetolites occur in the correlative interval (Lee et al. 2012, figs 8, 9). The depositional environments of the coral beds in the Xiazhen Formation are interpreted as back reef to marginal platform settings (Lee et al. 2012). No fossils that could indicate a precise age (e.g., graptolites or conodonts) have been found in the formation, but trilo- bites and brachiopods suggest that it is mid-Ashgill (Zhan et al. 2002, Zhang et al. 2007). Based on corals and a proposed correlation with the Changwu Formation, Zhang et al.(2007) estimated the Xiazhen Formation to be of early to late Katian age (middle Ashgill).

Material and methods Coralla from the Xiazhen Formation at Zhuzhai are superficially well preserved, but recrystallization and silicification commonly obscure their internal structures. Over 500 coralla of Agetolites were collected, including 108 relatively well-preserved specimens used for multivariate analysis. Of these specimens, 107 are from sub- sections ZU 1 and ZU 2 (Table 1), and one is from talus at sub-section ZU 3. Also used in the analysis are Fig. 2. Lithostratigraphic columns showing relevant portions of the six type specimens of Agetolites species designated by Xiazhen Formation (Upper Ordovician) at sub-sections ZU 1, ZU 2 and ZU 3, Zhuzhai, South China (modified after Lee et al. 2012; for Lin (1960) from the Upper Ordovician at Shiyanshan, complete columns and correlation, see Lee et al. 2012, figs 4, 8). which is located 5 km northeast of Zhuzhai (Fig. 1A). Specimens examined in this study were collected from intervals A3– These include the holotypes of A. huangi Lin, 1960 and – A12 at ZU 1, A1 A3 at ZU 2, and the upper part of ZU 3-I. LLM, A. raritabulatus Lin, 1960, and paratypes of A. lower limestone member; LSM, lower shale member; MMM, middle mixed-lithology member; USM, upper shale member. S, shale; M, oculiporoides Lin, 1960 and A. yushanensis Lin, 1960 mudstone; W, wackestone; P, packstone; G, grainstone; F, floatstone. deposited in the Geological Museum of China in

5 IGSUN NING 254

Sub-section/ stratigraphic Agetolites species/number of interval specimens Orientation, growth form, and Member ZU 1 ZU 2 Lithofacies Relative energy level size of coralla AB C DE tal et Upper shale member A12 Shale, limestone–shale alternation Low to moderate Transported and in growth 11 2 1

including partially developed small position; mostly hemispherical . reefs, nodular calcareous mudstone with few branching; large and small Middle mixed lithology A11 Peloidal wackestone to packstone Moderate Transported; hemispherical; small 1 member A10 Peloidal wackestone to packstone, Moderate to periodically high Mostly transported; hemispherical; 61 coral floatstone with peloidal mostly small packstone to grainstone matrix A9 Peloidal wackestone to packstone, Low to moderate Transported and in growth 21 limestone–shale alternation position; hemispherical; small A8 Peloidal packstone to grainstone, Moderate to high Transported and in growth 71 2 coral floatstone with peloidal position; hemispherical and some packstone to grainstone matrix branching; small A7 Peloidal wackestone (to packstone) Moderate to periodically high Transported and in growth 2 position; hemispherical and some branching; small A6 Calcareous mudstone Low to occasionally moderate Overturned and in growth 19 position; large hemispherical to small lenticular A5 Nodular calcareous mudstone Low Not in growth position; 55 1 hemispherical; large and small A4 Bioturbated wackestone Low (to moderate) Not in growth position; 1 hemispherical; large A3 A3 Coral floatstone, peloidal & Moderate to high Transported and in growth 0+2 2+11 2+5 bioclastic grainstone, shale position; hemispherical; large and small A2 Floatstone to framestone, peloidal Moderate to high Mostly in growth position; 65 41 packstone to grainstone hemispherical, lenticular, and few branching; commonly contain rod- shaped stromatoporoids; small Lower limestone member A1 Calcareous mudstone Low Not in growth position; 19 hemispherical and irregular; large and small ALCHERINGA Table 1. Distribution, orientation, growth form and size of Agetolites coralla in the Xiazhen Formation (Upper Ordovician) at Zhuzhai, South China. A, A. yushanensis; B, A. raritabulatus; C, A. waicunensis; D, A. oculiporoides; E, A. maxima. ALCHERINGA ORDOVICIAN CORALS FROM CHINA 255

(V2) is defined as the minimum thickness of the com- Specimen Identification Reference Designation mon double wall between corallites; lengths of long IV-3452 A. oculiporoides Lin (1960) Paratype septa (V3) and short septa (V4) are averages for the dis- IV-3454 A. huangi Lin (1960) Holotype tance from the distal end to proximal end in the com- IV-3463 A. yushanensis Lin (1960) Paratype mon wall, based on measurements of the relatively long IV-3464 A. yushanensis Lin (1960) Paratype IV-3465 A. yushanensis Lin (1960) Paratype and short septa, respectively; and corallite perimeter IV-3466 A. raritabulatus Lin (1960) Holotype (V7) is defined as the length of the median suture in the common wall bounding the corallite. V6 is a count Table 2. Six type specimens of Agetolites species from the Upper Ordovician at Shiyanshan in the JCY triangle region of of the total number of septa. Three characters are deter- South China, used for multivariate analysis. All specimens are mined by calculations. V5 is a ratio of the length of in the collection of the Geological Museum of China in Beijing. long septa (V3) to length of short septa (V4). V8 and V9 are ratios of corallite perimeter (V7) to the length of long septa (V3) and short septa (V4), respectively. A Beijing (Table 2). The holotypes of A. oculiporoides raw-data matrix of 108 coralla plus six type specimens and A. yushanensis are, however, unavailable and one by nine morphological characters (V1–V9) was con- paratype (IV-3460) of A. yushanensis was not used structed (see Appendix 1). Each coordinate is the aver- owing to inadequate preservation for precise morpho- age value of the measurements of five corallites logical comparison with our specimens. The type selected from each corallum; the exceptions are four specimens of A. multitabulatus Lin, 1960 and A. corallites from holotype IV-3454 and three corallites breviseptatus Lin, 1960 are inadequately preserved for from paratype IV-3465, owing to inadequate preserva- inclusion in our study or could not be located and are tion of other corallites. A multivariate analysis to dis- probably missing. All type specimens of species of Age- criminate closely related species and examine their tolites and Agetolitella erected by Lin & Chow (1977) intra- and interspecific variations was performed based from the JCY region were supposed to be deposited in on the principal-component score matrix obtained from the Institute of Geology, Chinese Academy of Geologi- the raw data set for the nine morphological characters. cal Sciences, and later moved to the Geological Frequency histograms and correlation analysis of the Museum of China, but we were unable to locate them nine characters for 114 coralla (including type speci- at either institution, and they are probably missing. mens) were performed to examine the completeness of The coralla of Agetolites are predominantly massive, the raw data and relationships among the characters. – domical or bulbous in growth form (Fig. 3A I), but Some of the characters are not independent, so a pyriform, tabular and even branching forms are also principal-component analysis was performed, and a clus- present. They are composed of prismatic corallites with ter analysis was conducted using the first three principal- well-developed septa that may alternate in length components score matrix. The unweighted pair-group (Fig. 4A). Tabulae are mostly complete (Fig. 4B, arrows method using arithmetic average was employed to gen- – fl 1 3) and at (Fig. 4B, arrow 1), with a few concave or erate a dendrogram of clusters of coralla, and each clus- slightly convex cases (Fig. 4B, arrows 2, 3), but some ter was considered to represent a morphospecies. The are incomplete (Fig. 4B, arrow 4) or irregular (Fig. 4B, identification of morphospecies was then determined by arrow 5). Mural pores are common (Fig. 4B, arrow P), quantitative and qualitative comparison with the type usually connecting two or three corallites (Fig. 4A, specimens that were available and suitable for study, and fi arrows 2, 3) and rarely four to even ve corallites with published descriptions and illustrations of other (Fig. 4A, arrow 4). Common walls are slightly crenu- described species. Discriminant analysis was performed lated, with a median suture (Fig. 4A, B, arrow M). to test the statistical validity of the morphospecies and type specimens recognized by cluster analysis. Finally, descriptive statistics and bivariate plots were performed Multivariate morphometrics to examine intra- and interspecific variation. A preliminary visual examination of the coralla led us In order to trace morphological variations during to suspect that there is a great range of morphological astogeny, serial transverse peels oriented perpendicular variation among the Agetolites specimens (Figs 4, 5). In to the central growth axis were prepared from 12 cor- order to incorporate these variations into systematics of alla, with up to 403 sections per corallum. In addition, the species, five corallites were selected for analysis 115 transverse and six longitudinal thin-sections of 115 among the largest 10 percent of corallites (based on coralla were prepared to compare skeletal development their tabularium area) in a transverse thin-section or and general morphology within and among the coralla. peel from the mature part of each corallum (Lee & All transverse sections illustrated herein are oriented as Noble 1988). Five morphological characters were mea- they appear viewed from above the corallum. Described sured for each corallite using an image-analysis system and figured specimens collected for this study are (image-Pro plus 5.0; Table 3; Fig. 6): tabularium area deposited in the Palaeontological Collections, Nanjing (V1) is defined as the area occupied by the polyp, Institute of Geology and Palaeontology, Chinese excluding the space filled by the septa; wall thickness Academy of Sciences in Nanjing (NIGP). Type 256 NING SUN et al. ALCHERINGA

Fig. 3. Field photographs of Agetolites in different stratigraphic intervals of the Xiazhen Formation at Zhuzhai, South China. A, Arrows point to small coralla in growth position on a grainstone surface in interval A2; B, C, Overturned large coralla on a calcareous mudstone surface in A1; D, E, Overturned coralla on a calcareous mudstone surface in A6; F, Small coralla on a grainstone surface in A8 (reefal facies); G, Arrows point to transported coralla of Agetolites with other colonial corals in A8; H, Arrow points to a corallum of Agetolites encrusted by a stromatoporoid in A8; I, Arrows point to small rod-shaped stromatoporoids encrusted by Agetolites in A2. Diameter of coin = 20 mm (A–C, I), 25 mm (F, H); scale bar on pencil = 40 mm (D); length of hammer = 26.5 cm (E); length of pencil = 13.5 cm (G). specimens with catalogue numbers having the prefixIV considerable (Fig. 7). The variation of four out of the are in the collection of the Geological Museum of nine characters is apparently continuous (V2, common China in Beijing. wall thickness; V3, length of long septa; V5, ratio of the length of long septa to length of short septa; V7, corallite perimeter); the Shapiro–Wilk test indicates that Frequency histograms these characters are normally distributed at the signifi- fi Frequency histograms of the nine morphological charac- cance level of 0.01. The variation of the other ve char- ters for the studied coralla and type specimens confirm acters does not deviate much from the normal that the overall range of morphological variation is distribution, as suggested by their skewness. A further ALCHERINGA ORDOVICIAN CORALS FROM CHINA 257

Fig. 4. Transverse and longitudinal thin-sections illustrating morphological characteristics of Agetolites from the Xiazhen Formation at Zhuzhai, South China. A, A. raritabulatus, NIGP PZ162434; arrow M points to common walls with median suture; arrows 2–4 point to corner pores connecting two, three and four corallites, respectively. B, A. raritabulatus, NIGP PZ162437; arrows M and P point to common walls with median suture and corner pores, respectively; arrows 1–5 point to complete, concave, convex, incomplete and irregular tabulae, respectively. Scale bar = 5 mm.

A principal-component analysis was conducted to Abbreviation Description Unit convert the original morphological characters into major components. Eigenvalues and their associated eigenvec- V1 Tabularium area mm2 V2 Common wall thickness mm tors of the nine morphological characters were calcu- V3 Length of long septa mm lated from the correlation matrix of the raw-data matrix, V4 Length of short septa mm and then three principal components accounting for V5 Ratio of V3 to V4 87.2% of total variance were extracted (Table 5). The V6 Number of septa no. first principal component (Prin 1), which accounts for V7 Corallite perimeter mm V8 Ratio of V7 to V3 68.8% of the variance, is weighted heavily on six mor- V9 Ratio of V7 to V4 phological characters: tabularium area (V1), length of short septa (V4), number of septa (V6), corallite Table 3. Morphological characters used in this study of perimeter (V7), ratio of perimeter to the length of long Agetolites Sokolov, 1955. septa (V8) and ratio of perimeter to the length of short septa (V9; Table 5). Among these characters, the ratio of perimeter to the length of short septa possesses the analysis is, however, required to determine whether highest eigenvector of Prin 1. The second principal only one species contributes to the overall distribution. component (Prin 2), which is weighted heavily on the ratio of the length of long septa to the length of short septa (V5), accounts for 10.1% of the variance (Table 5). Correlation and principal-component analyses The third principal component (Prin 3), which is To examine the linear relationship between each pair of weighted heavily on the length of long septa (V3), morphological characters, Pearson correlation coeffi- accounts for 8.3% of the variance (Table 5). cients were calculated for the raw-data matrix (Table 4). The coefficient matrix shows that six out of the nine Cluster analysis and identification of species characters are strongly related to each other at the significance level of 0.01 using the t-test: tabularium area In order to distinguish species represented by the col- (V1), length of short septa (V4), number of septa (V6), lected coralla, a cluster analysis was performed for the corallite perimeter (V7), ratio of perimeter to the length first three principal components (Fig. 8). The resulting of long septa (V8) and ratio of perimeter to the length dendrogram yields five major clusters separated at a rel- of short septa (V9). These characters, except for the ative average distance of 15. Three of the five clusters length of short septa, are positively related to each are considered to correspond to Agetolites yushanensis, other. Among them, tabularium area and corallite A. raritabulatus and A. oculiporoides, respectively, perimeter display the strongest positive relationship. because they include the type specimens of those 258 NING SUN et al. ALCHERINGA

V1 V2 V3 V4 V5 V6 V7 V8 V9 V1 r 1.000 –0.446 –0.539 –0.681* 0.494 0.662* 0.976* 0.912* 0.866* p <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 V2 r 1.000 0.406 0.499 –0.409 –0.433 –0.407 –0.461 –0.524 p <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 V3 r 1.000 0.717* –0.273 –0.404 –0.516 –0.809* –0.721* p <0.001 0.003 <0.001 <0.001 <0.001 <0.001 V4 r 1.000 –0.840* –0.581 –0.676* –0.765* –0.914* p <0.001 <0.001 <0.001 <0.001 <0.001 V5 r 1.000 0.465 0.508 0.440 0.751* p <0.001 <0.001 <0.001 <0.001 V6 r 1.000 0.683* 0.638* 0.647* p <0.001 <0.001 <0.001 V7 r 1.000 0.912* 0.869* p <0.001 <0.001 V8 r 1.000 0.917* p <0.001 V9 r 1.000 p Table 4. Simple correlation matrix of nine morphological characters (V1–V9; see Table 3 for abbreviations) selected from 108 coralla of Agetolites from the Xiazhen Formation (Upper Ordovician) at Zhuzhai and six type specimens from the Upper Ordovician at Shiyanshan, South China (see Table 2)[r, Pearson correlation coefﬁcient; p, probability by t-test (H0: Rho = 0, Prob. > |r|)]. *Values showing strong correlation between morphological characters at signiﬁcance level 0.01 using the t-test.

Prin 1 Prin 2 Prin 3 V1 0.903* 0.252 0.242 V2 – 0.591* 0.294 0.328 V3 – 0.731* – 0.254 0.581* V4 – 0.900* 0.299 0.144 V5 0.693* – 0.662* 0.169 V6 0.741* 0.028 0.319 V7 0.901* 0.250 0.292 V8 0.939* 0.320 – 0.076 V9 0.980* – 0.059 – 0.015 Eigenvalue 6.189 0.912 0.747 Proportion of variance 0.688 0.101 0.083 Cumulative proportion of variance 0.688 0.789 0.872 Table 5. First three principal components (Prin 1–Prin 3) in principal-component analysis of 114 coralla and nine morphological characters of Agetolites (V1–V9; see Table 3 for abbreviations). *Values showing that V1–V9 are heavily weighted on Prin 1, V5 on Prin 2 and V3 on Prin 3. species. The three paratypes of A. yushanensis are all Discriminant analysis and descriptive statistics within the same cluster. The holotype of A. raritabula- In order to verify each of the five morphospecies, a tus and the paratype of A. oculiporoides occur in differ- canonical discriminant analysis using the original nine ent clusters, but the cluster containing A. oculiporoides morphological characters was performed. Two canonical also includes the holotype of A. huangi. Further com- discriminant functions were obtained, which account for parison of the latter two species supports the interpreta- 70.3% and 19.8% of the variance. The plot of the two tion that A. huangi is a junior synonym of A. functions (Fig. 9) demonstrates that three of the five oculiporoides (see Systematic palaeontology). The species are distinctly separated from each other: Ageto- remaining two clusters do not incorporate type speci- lites yushanensis, A. waicunensis and A. maxima. mens. Based on morphological similarity, coralla in Although partial overlapping is evident for the mor- those two clusters are identified as A. waicunensis (Lin phospace occupied by A. raritabulatus and A. oculi- & Chow, 1977) and A. maxima (Lin & Chow, 1977), poroides, they are regarded as separate species based on which were originally described from the middle their different centroids. Sanqushan Formation (Upper Ordovician), 3.5 km west Descriptive statistics of the nine morphological of Tashan, near Zhuzhai (Fig. 1A; see Systematic characters were calculated. The average value for most palaeontology). ALCHERINGA ORDOVICIAN CORALS FROM CHINA 259 characters appears to be distinctly different from one species to another (Table 6). However, the ranges of – values for most characters partially overlap among the species (Fig. 10). Bivariate plots with r2 (r, Pearson Agetolites correlation coefficient) were prepared to estimate variability of the characters among species and to aid in

distinguishing the species (Fig. 11). For example, on a is a value of corallite ve species of plot of tabularium area (V1) and corallite perimeter D ﬁ (V7; Fig. 11A), Agetolites yushanensis is distinctly sep- 7.23 5.91 6.48 arated from A. maxima; the morphospaces occupied by

the other three species strongly overlap each other. A s studies, plot of the ratio of the length of long septa to length of

short septa (V5) and the ratio of perimeter to the length – of short septa (V9) shows that A. yushanensis, A. raritabulatus and A. maxima are distinguishable from one another (Fig. 11B). Based on the relationship between corallite perimeter (V7) and the ratio of perimeter to the length of long septa (V8), the ﬁve species are clearly distinguishable (Fig. 11C). However, based on the relationship between corallite perimeter

(V7) and the ratio of perimeter to the length of short 6.59 3.92 5.16 septa (V9), only A. yushanensis is distinctive (Fig. 11D). The descriptive statistical results demon- strate that A. yushanensis and A. maxima are more

readily distinguishable than the other three species. –

Palaeoecological distribution of Agetolites In order to examine the facies distribution of the spe- for abbreviations and units) based on the coralla and type specimens of cies of Agetolites, each corallum was judged to be 3

autochthonous or allochthonous according to the orien- 6.07 4.59 5.29 tation and position in which it was found, its degree of abrasion, and its relation to the enclosing sedimentary deposit. The size and shape of coralla, the associated V9; see Table – fauna and growth relationships of the corals, especially – with stromatoporoids, were also considered. In the Xiazhen Formation, species of Agetolites occur in various facies represented by a wide range of depositional environments. The general association of

Agetolites, tabulate corals including halysitids and heli- (i.e., assuming the corallite is circular, which is a close approximation for hexagonal to octagonal corallites in the size range of this olitids, solitary and colonial rugose corals, and stro- π matoporoids in many beds probably indicates broadly similar ecological tolerances. However, rugose corals 5.54 4.26 4.81 are rather uncommon in the formation and stromatoporoids are more dominant in pure limestone reef facies, where Agetolites and other corals are less com- – mon to almost entirely absent. Stratigraphic intervals in which the coralla of identi- ﬁed Agetolites species were collected are summarized (Table 1). All coralla used in this study were collected from 12 Agetolites-bearing intervals in sub-sections ZU 1 and ZU 2 (Fig. 2). Sub-section ZU 3 is laterally equivalent to the upper part of ZU 1, and the same Descriptive statistics of nine morphological characters (V1 4.41 2.66 3.68

species of Agetolites occur in the correlative strata (see Agetolites yushanensisMax. Min. Avg. SD Agetolites raritabulatus Max. Min. Avg. Agetolites waicunensis SD Max. Min. Agetolites oculiporoides Avg. SD Max. Agetolites maxima Min. Avg. SD Max. Min. Avg. SD Lee et al. 2012, ﬁgs 8, 9). Agetolites is not found in diameter (mm) calculated for convenience as V7/ study). Table 6. (max., maximum; min., minimum; avg., average; SD, standard deviation). For comparison with measurements of corallite diameter reported in previou shale facies of the formation. V1V2 8.57V3 0.32V4 3.08 1.10V5 0.22 0.69 5.78V6 0.89 2.07 0.26 1.27V7 18.75 0.46 0.95 0.02V8 13.86 1.42 15.40 0.55 0.05V9 14.21 16.41 15.36 8.37 1.73 0.06D 27.53 0.83 9.09 11.56 0.15 0.29 7.83 15.57 12.19 1.00 1.47 11.29 21.06 0.20 0.44 1.31 20.00 2.20 0.77 2.41 3.21 0.24 16.00 0.24 17.41 0.91 0.02 18.04 1.95 19.93 13.37 19.55 60.00 0.36 0.07 0.91 14.23 15.11 2.60 10.24 30.19 0.06 16.78 1.11 0.38 14.44 0.29 43.95 1.83 20.00 0.86 9.44 2.60 0.16 17.00 0.43 19.06 0.62 3.09 18.22 0.23 28.03 14.42 0.22 83.55 20.97 0.74 18.86 16.63 1.86 0.83 0.04 39.20 0.32 22.76 6.68 0.05 53.68 1.28 2.35 0.06 13.41 2.69 11.33 20.00 0.34 0.31 17.20 4.67 20.70 1.18 0.23 18.37 23.28 0.54 69.00 12.33 0.89 3.22 12.30 24.18 0.27 16.21 27.71 0.82 0.30 1.03 15.83 39.97 17.57 1.96 0.03 2.45 0.43 14.21 21.52 0.08 3.12 21.00 2.46 3.66 0.08 18.00 22.71 0.42 0.28 79.29 19.17 33.90 18.57 0.86 49.09 0.18 1.05 23.09 20.35 0.43 62.16 0.67 27.08 2.59 1.53 0.23 0.29 7.75 3.52 0.76 0.02 2.01 0.33 0.06 2.30 0.04 0.18 260 NING SUN et al. ALCHERINGA

Three of the five species of Agetolites in the important controlling factors in the distribution of the Xiazhen Formation have restricted stratigraphic species of Agetolites. distributions (Table 1). Agetolites waicunensis and A. maxima occur in the lower part of the formation (intervals A1–A6), whereas A. yushanensis is restricted Systematic palaeontology to the upper part (intervals A6–A12), with overlap of A. Phylum CNIDARIA Hatschek, 1888 waicunensis and A. yushanensis only in interval A6. On Class ANTHOZOA Ehrenberg, 1834 the other hand, A. raritabulatus and A. oculiporoides Subclass TABULATA Milne-Edwards & Haime, 1850 show relatively longer stratigraphic ranges in the forma- Order FAVOSITIDA Wedekind, 1937 tion. Suborder FAVOSITINA Wedekind, 1937 On bedding surfaces within Agetolites-bearing inter- Family AGETOLITIDAE Kim, 1962 vals, the coralla can be grouped into three types of Agetolites Sokolov, 1955 occurrences, listed in order of decreasing abundance: (1) coralla in growth position on calcareous mudstone Type species. Agetolites mirabilis Sokolov, 1955 from layers (interval A2 in sub-section ZU 2; Fig. 3A); (2) the ‘lower Llandoverian’ in the Chingiz Range of Kaza- coralla mostly toppled or overturned on calcareous khstan. Kim (1966), however, speculated that the mudstone or marl layers (notably interval A1 in sub- deposit from which the genus was reported by Sokolov section ZU 2 and A6 in ZU 1; Fig. 3B–E); and (3) is Upper Ordovician. transported coralla (interval A3 in sub-sections ZU 1 and ZU 2, and A7–A12 in ZU 1; Fig. 3F, G) and Emended diagnosis. Corallum hemispherical, nodular, abraded coralla (interval A8 in sub-section ZU 1 and its pyriform or cylindrical, cerioid; corallites prismatic; equivalent in ZU 3). common walls with sinuous median suture; septa alter- Although the size and shape of Agetolites coralla are nately long and short thin plates with long axial parts primarily considered to be species-characteristic fea- spinose; tabulae horizontal, convex or concave, com- tures, they also appear to be related to lithofacies. Large monly complete, in some cases incomplete or irregular; coralla of A. waicunensis and A. maxima, usually domi- pores at or near angles between corallites, rounded and cal in form and up to 50 cm in diameter and 40 cm numerous, commonly opening simultaneously into three high, commonly occur in calcareous mudstone facies of adjacent corallites, but may open into two, four or even interval A6 (Fig. 3E) in sub-section ZU 1 and interval five adjacent corallites, pores may occur rarely on faces A1 (Fig. 3B) in sub-section ZU 2 (Table 1). Smaller of corallite walls. coralla of A. raritabulatus and A. yushanensis, usually less than 15 cm in diameter and 10 cm high, with dom- Discussion. The above diagnosis largely follows Hill ical, pyriform or, in some cases, branching forms, are (1981, pp. F559, F560), but with additions to the state- common in reef or reef-related facies of interval A2 ments regarding tabulae and pores based on the present (Fig. 3A) in sub-section ZU 2, and intervals A8 study. (Fig. 3F) and A12 in sub-section ZU 1 (Table 1). According to Hill (1981, p. F561), Agetolitella is Within these reefal intervals, selection of suitable sub- distinguished from Agetolites by having septa that do strates commonly resulted in coralla of Agetolites not alternate in length and by having pores on the encrusting stromatoporoids (Fig. 3I), together with stro- faces of corallite walls and at or near the angles matoporoids encrusting Agetolites (Fig. 3H). between faces. Species from South China that were Two species, Agetolites waicunensis and A. maxima, assigned to Agetolitella by Lin & Chow (1977) have commonly occur in fine-grained calcareous mudstones alternating long and short septa, as is characteristic of of interval A6 in sub-section ZU 1, and interval A1 in Agetolites. Lin & Chow (1977) claimed that wall pores sub-section ZU 2, respectively, which are interpreted as are present in all their species of Agetolitella. Based relatively low-energy deposits. Agetolites yushanensis is on their illustrations, however, the species range from common in coarse-grained grainstone facies of intervals having no wall pores, to rare wall pores in some cor- A7 to A10 in sub-section ZU 1, representing moderate- alla, to rare wall pores in all coralla. This suggests energy deposits. Agetolites raritabulatus and A. oculi- intergradation between Agetolites and Agetolitella with poroides occur in strata that were deposited in a wider respect to the development of wall pores. In two of range of conditions. These include lower-energy depos- the species described below from Zhuzhai (A. wai- its (A. raritabulatus in intervals A4, A5, A9 and A12 cunensis, A. maxima), our relatively large collections of sub-section ZU 1; A. oculiporoides in interval A1 of show that rare wall pores occur in some, but not all, sub-section ZU 2, and A12 of ZU 1) and moderate- of the coralla. We do not consider the sporadic devel- energy deposits (A. raritabulatus in intervals A2 and opment of rare wall pores to justify the assignment of A3 of sub-section ZU 2, and A8 and A11 of ZU 1; A. such species to Agetolitella rather than Agetolites. Spe- oculiporoides in interval A2 of sub-section ZU 2, and cies from South China that were previously assigned A8 and A10 of ZU 1). The depositional energy level to Agetolitella are herein transferred to Agetolites and interactions with other sessile biota apparently were (Table 7). ALCHERINGA ORDOVICIAN CORALS FROM CHINA 261

Location Species References Shiyanshan, Tashan Agetolites oculiporoides Lin (1960), Yu & Zhang (1963), Lin & Chow (1977) Shiyanshan, Tashan A. huangi Lin (1960), Yu & Zhang (1963), Lin & Chow (1977) Shiyanshan, Tashan A. multitabulatus Lin (1960), Yu & Zhang (1963), Lin & Chow (1977) Shiyanshan, Tashan A. yushanensis Lin (1960), Yu & Zhang (1963), Lin & Chow (1977) Shiyanshan A. raritabulatus Lin (1960), Yu & Zhang (1963), Lin & Chow (1977) Shiyanshan, Tashan A. breviseptatus Lin (1960), Yu & Zhang (1963), Lin & Chow (1977) Shiyang A. grandiformis Lin & Chow (1977) Tashan A. triangulatus Lin & Chow (1977) Tashan A. intermedius Lin & Chow (1977) Tashan A. crassus Lin & Chow (1977) Tashan A. aquabilis Lin & Chow (1977) Huibu A. hemiagetolitoides Lin & Chow (1977) Yanrui, Shiyanshan, Tashan A. rariseptatus Lin & Chow (1977) Tashan A. sinensis Lin & Chow (1977) Yanrui A. paleofavositoides Lin & Chow (1977) Tashan Agetolitella tenuis Lin & Chow (1977) Tashan A. xiazhenensis Lin & Chow (1977) Tashan A. crassiseptata Lin & Chow (1977) Tashan A. tashanensis Lin & Chow (1977) Tashan A. concava Lin & Chow (1977) Tashan A. jiangshanensis Lin & Chow (1977) Tashan A. maxima Lin & Chow (1977) Tashan A. waicunensis Lin & Chow (1977) Yanrui A. gracilis Lin & Chow (1977) Tashan A. micropora Lin & Chow (1977) Table 7. Fifteen species of Agetolites and ten species of Agetolitella reported previously from the Upper Ordovician at Shiyanshan and from the Sanqushan Formation (Upper Ordovician) at other locations in the JCY triangle region, South China (see Fig. 1A). Species assigned to Agetolitella by Lin & Chow (1977) are herein transferred to Agetolites.

Our study of material from South China calls into Emended diagnosis. Corallites polygonal in transverse question the distinction of Agetolitella and Agetolites section. Species average of corallite perimeter 11.56 based on the position of wall pores, raising the mm, tabularium area 5.78 mm2, length of short septa possibility that the former genus is a junior synonym of 0.55 mm, length of long septa 0.95 mm, ratio of aver- the latter. As currently understood, however, the nature age length of long septa to length of short septa 1.73, of septa (whether equal in length or alternating in number of septa 16.41. Wall pores absent. length) remains a diagnostic character distinguishing these genera. This should be tested by examining intra- Description. Corallites polygonal in transverse section, and interspecific variability in material from other adult corallites mostly hexagonal, shape of offsets regions, including the type species Agetolitella prima rounded or triangular (Fig. 5A; Sun et al. 2014, fig. Kim, 1962 from the Upper Ordovician of Uzbekistan 3a–n). Corallum averages of corallite perimeter 8.37– and Agetolites mirabilis. Such an analysis is beyond the 13.86 mm, tabularium area 3.08–8.57 mm2, length of scope of the present study. septa 0.46–1.10 mm, ratio of average length of long septa to length of short septa 1.42–2.07, number of Agetolites yushanensis Lin, 1960 (Fig. 5A, B) septa 15–19, wall thickness 0.22–0.32 mm (Table 6). 1960 Agetolites yushanensis Lin, p. 58, pl. VII, fig. 1a, Septa well developed, some long septa reach centre of b, pl. VIII, figs 1a, b, 2a, b, pl. IX, fig. 1a, b. corallite with curved distal ends (Fig. 5A). Corner pores 1963 Agetolites yushanensis Lin; Lin in Yu & Zhang, commonly open to three corallites simultaneously, no p. 217, pl. 68, fig. 3a, b. wall pores evident (Fig. 5A). Tabulae mostly incom- 1977 Agetolites yushanensis Lin; Lin in Lin & Chow, plete, subhorizontal, slightly convex or concave, a few p. 140, pl. 25, fig. 2a, b. irregular (Fig. 5B).

Material. Twenty-nine coralla (NIGP PZ162402– Discussion. The examined type specimens of 162419, 162421–162431) from intervals A6–A10 and Agetolites yushanensis from the Sanqushan Formation A12 at sub-section ZU 1 (Fig. 2; Table 1) and one at Shiyanshan (paratypes IV-3463, IV-3464, IV-3465; corallum from talus at sub-section ZU 3 (NIGP see Lin 1960) are quite different from one another in PZ162420), Xiazhen Formation (Katian) at Zhuzhai, corallite size (tabularium area, V1; corallite perimeter, South China; paratypes IV-3463, IV-3464, IV-3465 (Lin V7; corallite diameter, D; Table 8), suggesting sub- 1960) from the Sanqushan Formation (Upper Ordovi- stantial intraspeciﬁc variation. All the type specimens cian) at Shiyanshan, South China. described by Lin (1960) are similar in corallite size to 262 NING SUN et al. ALCHERINGA

Fig. 5. Transverse and longitudinal thin-sections showing four species of Agetolites from the Xiazhen Formation at Zhuzhai, South China. A, B, A. yushanensis, NIGP PZ162423; C, D, A. waicunensis, NIGP PZ162455; E, A. oculiporoides, NIGP PZ162487; F, A. oculiporoides, NIGP PZ162490; G, H, A. maxima, NIGP PZ162501, arrow in G points to wall pore; scale bar = 5 mm. ALCHERINGA ORDOVICIAN CORALS FROM CHINA 263

A. yushanensis A. raritabulatus A. oculiporoides A. huangi P. IV-3463 P. IV-3464 P. IV-3465 H. IV-3466 P. IV-3452 H. IV-3454 V1 6.21 4.47 5.54 7.83 9.11 12.51 V2 0.30 0.32 0.31 0.25 0.31 0.28 V3 1.00 0.91 0.94 0.86 0.95 1.09 V4 0.53 0.53 0.55 0.44 0.43 0.49 V5 1.87 1.71 1.69 1.95 2.20 2.24 V6 16.50 15.60 15.67 19.00 18.00 19.25 V7 12.15 9.23 12.27 13.37 14.99 15.65 V8 12.20 10.15 13.10 15.52 15.85 14.33 V9 22.87 17.38 22.13 30.19 34.91 32.13 D 3.87 2.94 3.91 4.26 4.77 4.98 Table 8. Average values of nine morphological characters (V1–V9; see Table 3 for abbreviations and units) for six type specimens of Agetolites species previously reported from the Upper Ordovician at Shiyanshan in the JCY triangle region, South China (H., holotype; P., paratype; see Table 2). For comparison with measurements of corallite diameter reported in previous studies, D is a value of corallite diameter (mm) calculated for convenience as V7/π (i.e., assuming the corallite is circular, which is a close approximation for hexagonal to octagonal corallites in the size range of this study). our coralla from the Xiazhen Formation at Zhuzhai phometric analysis and qualitative morphological (Tables 6, 8, 9). Lin (1960), Yu & Zhang (1963) and comparisons, we identify the coralla from Zhuzhai as Lin & Chow (1977) mentioned that long septa in A. yushanensis. A. yushanensis extend nearly to the centre of the In our collection, corallite size is quite variable. In corallite and have bent distal ends, as also observed intervals A9 and A10, average corallite sizes (V1, V7) in our coralla (Fig. 5A). Based on the results of mor- are larger than in A6–A8 and A12 (Table 9). In addition,

Species Stratigraphic intervalicinterval V1 V2 V3 V4 V5 V6 V7 V8 V9 D A. yushanensis A12 5.42 0.25 0.95 0.54 1.76 15.98 11.50 12.09 21.33 3.66 T 7.40* 0.27 1.01 0.66 1.55 17.20 13.86 13.69 21.15 4.41 A10 6.72 0.26 0.99 0.57 1.73 16.67 12.72 12.92 22.39 4.05

A9 6.99 0.24 0.94 0.63 1.49 17.07 12.70 13.50 20.06 4.04 A8 5.23 0.26 0.92 0.52 1.78 16.57 10.45 11.37 20.18 3.33 A7 5.15 0.27 0.92 0.51 1.80 17.00 10.25 11.16 19.88 3.26 A6 6.08 0.28 0.89 0.58 1.54 16.60 12.30 13.82 21.21 3.92

A. raritabulatus A12 9.27 0.26 0.94 0.41 2.30 17.00 14.51 15.40 35.44 4.62 A11 9.16 0.26 0.97 0.40 2.43 16.00 13.98 14.39 34.95 4.45 A9 9.33 0.23 1.00 0.42 2.38 17.80 14.91 14.95 35.50 4.75 A8 9.92 0.28 0.98 0.40 2.48 18.00 14.01 14.23 35.33 4.46 A5 12.47 0.23 0.86 0.29 3.02 18.28 15.89 18.49 55.73 5.06 A4 12.77 0.23 0.89 0.30 2.94 17.60 16.09 18.09 53.18 5.12 A3 of ZU 2 8.97 0.26 0.78 0.31 2.65 18.63 13.81 17.64 46.80 4.40 A2 12.99* 0.23 0.94 0.38 2.48 18.30 15.64 16.64 41.13 4.98

A. waicunensis A6 14.14 0.25 0.74 0.32 2.35 18.09 16.59 22.59 53.12 5.28 A5 13.61 0.23 0.76 0.30 2.56 18.00 15.93 20.97 53.74 5.07 A3 of ZU 1 18.06* 0.17 0.75 0.28 2.77 18.00 18.48 24.98 69.91 5.88 A3 of ZU 2 15.28 0.21 0.69 0.31 2.25 18.49 16.92 24.53 55.63 5.39 A2 12.54 0.23 0.80 0.37 2.19 18.20 16.00 20.04 43.88 5.09

A. oculiporoides A12 9.37 0.27 1.11 0.52 2.13 17.40 14.48 13.08 27.85 4.61 A10 6.68 0.30 1.00 0.51 1.96 19.00 12.33 12.30 24.18 3.92 A8 10.33 0.29 1.04 0.48 2.19 17.90 14.39 13.86 30.40 4.58 A2 17.06 0.24 1.06 0.38 2.81 18.65 17.84 16.89 47.69 5.68 A1 20.97* 0.26 0.89 0.30 2.96 18.00 20.70 23.28 69.00 6.59

A. maxima A5 18.72 0.28 0.80 0.33 2.41 18.00 18.77 23.59 56.88 5.97 A3 of ZU 1 24.12* 0.25 0.85 0.41 2.05 18.50 21.39 25.27 51.92 6.81 A3 of ZU 2 18.46 0.21 0.75 0.31 2.44 20.28 19.02 25.22 61.48 6.05 A2 17.79 0.24 0.75 0.32 2.37 19.33 18.85 25.21 59.63 6.00 A1 23.36 0.24 0.74 0.33 2.26 18.81 21.20 29.12 65.67 6.75 Table 9. Average values of nine morphological characters (V1–V9; see Table 3 for abbreviations and units) of the five species of Agetolites in stratigraphic intervals of the Xiazhen Formation (Upper Ordovician) at Zhuzhai, South China (see Table 1, Fig. 2;T, talus). For each species, an asterisk under V1 indicates the stratigraphic interval where tabularium area is largest. For comparison with measurements of corallite diameter reported in previous studies, D is a value of corallite diameter (mm) calculated for convenience as V7/π (i.e., assuming the corallite is circular, which is a close approximation for hexagonal to octagonal corallites in the size range of this study). 264 NING SUN et al. ALCHERINGA the length of long septa (V3) is greater in intervals A9, alla, average 11 to 15 per 5 mm vertically in sparse A10 and A12 than in A6–A8 (Table 9). bands, 15 to 21 in dense bands (Fig. 4B). In a comparison of the average values of morphological characters, Agetolites yushanensis is distin- Discussion. Corallite sizes reported in all the type guished by its smaller corallite sizes (V1, V7), fewer specimens of Agetolites raritabulatus from the San- septa (V6) and lower ratios of perimeter to septal qushan Formation at Shiyanshan (diameters 3–4mm lengths (V8, V9) than the other four species of Ageto- in Lin 1960, p. 58; 3–4 mm in Yu & Zhang 1963, lites recognized in the Xiazhen Formation at Zhuzhai: p. 218; 2.5–4 mm in Lin & Chow 1977, p. 139) are A. raritabulatus, A. waicunensis, A. oculiporoides and slightly smaller than in our coralla from the Xiazhen A. maxima (Table 6). Tabularium area (V1) and ratios Formation at Zhuzhai. However, the value of corallite of corallite perimeter to septal lengths (V8, V9) are less diameter (D) calculated in the present study for the variable in A. yushanensis than in those four species holotype of A. raritabulatus (4.26 mm; Table 8)is (Fig. 10A, H, I). Agetolites minor Lin, 1963,as close to the range of average values for coralla in reported from the Upper Ordovician at Shanyang in stratigraphic intervals at Zhuzhai (4.40–5.12 mm; Shaanxi Province, North China (Lin 1963, p. 120), has Table 9). Lin (1960), Yu & Zhang (1963) and Lin corallite sizes (diameter commonly 2.5–3 mm) and sep- & Chow (1977) mentioned that long septa in A. tal lengths (0.75–0.9 mm) that are within the range of raritabulatus stretch nearly to the centre of the A. yushanensis (Table 6). However, A. minor is distinct corallite and in a few cases have bent distal ends. in having more septa (18–20; Lin 1963, p. 120) than A. However, such long septa are not commonly evident yushanensis (V6; Table 6). in the type specimens or in our coralla (Fig. 4A). Compared with our specimens, the holotype of A. Agetolites raritabulatus Lin, 1960 (Fig. 4A, B) raritabulatus described by Lin (1960, p. 58) has many 1960 Agetolites raritabulatus Lin, p. 58, pl. IX, fewer tabulae (3–5 tabulae per 5 mm in sparse bands, fig. 2a, b. 7–9 in dense bands). However, considering the vari- 1963 Agetolites raritabulatus Lin; Lin in Yu & Zhang, ability seen in our collection (Fig. 4B), spacing of p. 218, pl. 68, fig. 5a, b. tabulae is not considered to be a reliable criterion to 1977 Agetolites raritabulatus Lin; Lin in Lin & Chow, discriminate species. Based on the results of a mor- fi phometric analysis (which included the holotype) and pp. 139, 140, pl. 25, g. 3a, b. qualitative morphological comparisons, we identify the Material. Nineteen coralla (NIGP PZ162432–162450) coralla from Zhuzhai as A. raritabulatus. from intervals A2 and A3 at sub-section ZU 2, and A4, Corallite size is quite variable in our collection. The A5, A8, A9, A11 and A12 at ZU 1 (Fig. 2; Table 1), average tabularium area (V1) and corallite perimeter Xiazhen Formation (Katian) at Zhuzhai, South China; (V7) are larger in intervals A2, A4 and A5 than in A3, holotype IV-3466 (Lin 1960) from the Sanqushan A8, A9, A11 and A12 (Table 9). In addition, a higher Formation (Upper Ordovician) at Shiyanshan, South ratio of the length of long septa to length of short septa China.

Emended diagnosis. Corallites polygonal in transverse section. Species average of corallite perimeter 15.11 mm, tabularium area 11.29 mm2, length of short septa 0.36 mm, length of long septa 0.91 mm, ratio of average length of long septa to length of short septa 2.60, number of septa 18.04. Wall pores absent.

Description. Corallites polygonal in transverse section, adult corallites hexagonal to octagonal (Fig. 4A). Corallum averages of corallite perimeter 13.37–17.41 mm, tabularium area 7.83–15.36 mm2, length of septa 0.24–1.00 mm, ratio of average length of long septa to length of short septa 1.95–3.21, number of septa 16–20, wall thickness 0.22–0.29 mm (Table 6). Septa well developed, some long septa reaching centre of corallite with curved distal ends (Fig. 4A). Corner pores commonly open to three corallites simultaneously, no wall pores evident (Fig. 4A). Tabulae mostly complete, subhorizontal or slightly convex or concave, few Fig. 6. Schematic transverse section of Agetolites, showing incomplete or irregular (Fig. 4B). Frequency of tabulae measurement of ﬁve morphological characters used in this study – in longitudinal section varies within and between cor- (V1 V4, V7; see Table 3 for abbreviations). ALCHERINGA ORDOVICIAN CORALS FROM CHINA 265

(V5) is apparent in intervals A4 and A5 than in A2, Emended diagnosis. Corallites sub-polygonal to polygo- A3, A8, A9, A11 and A12 (Table 9). nal in transverse section. Species average of corallite Agetolites raritabulatus is distinguished from A. perimeter 16.63 mm, tabularium area 14.44 mm2, length yushanensis and A. maxima in average corallite sizes of short septa 0.32 mm, length of long septa 0.74 mm, (Fig. 10A, G), and from A. waicunensis and A. oculi- ratio of average length of long septa to length of short poroides in the average length of long septa (Fig. 10C). septa 2.35, number of septa 18.22. Very rare wall pores This species has the highest average ratio of the length in some coralla. of long septa to length of short septa (V5), compared with the other four species of Agetolites recognized in Description. Corallites polygonal in transverse section, the Xiazhen Formation at Zhuzhai: A. yushanensis, A. adult corallites hexagonal to octagonal or rarely with waicunensis, A. oculiporoides and A. maxima (Table 6). nine to 11 sides, shape of offsets rounded or rectangular (Fig. 5C; Sun et al. 2014, ﬁg. 6a–l). Corallum Agetolites raritabulatus has a higher average value for the – number of septa (V6) than A. yushanensis (Table 6). averages of corallite perimeter 14.42 19.06 mm, tabularium area 10.24–19.55 mm2, length of septa 0.22–0.86 mm, ratio of average length of long septa Agetolites waicunensis (Lin & Chow, 1977) (Fig. 5C, D) to length of short septa 1.86–3.09, number of septa – – 1977 Agetolitella waicunensis Lin & Chow, pp. 148, 17 20, wall thickness 0.16 0.29 mm (Table 6). Septa 149, pl. 31, ﬁgs 1a, b, 2a, b. well developed, relatively short (Fig. 5C). Corner pores numerous, commonly open to three corallites Material. Thirty-two coralla (NIGP PZ162451–162482) simultaneously (Fig. 5C); wall pores very rare in from intervals A2 and A3 at sub-section ZU 2, and A2, some, but not all, coralla. Tabulae mostly complete, A5 and A6 at ZU 1 (Fig. 2; Table 1), Xiazhen Forma- subhorizontal or slightly convex or concave, few tion (late Katian) at Zhuzhai, South China. incomplete or irregular (Fig. 5D).

Fig. 7. A–I, Frequency histograms of nine morphological characters (V1–V9; see Table 3 for abbreviations; units shown in parentheses) for 108 coralla and six type specimens of Agetolites (avg., average; s.d., standard deviation; skew., skewness; no., number of coralla). 266 NING SUN et al. ALCHERINGA

Fig. 9. Plot of canonical discriminant scores of 108 coralla and six type specimens of Agetolites, using the ﬁrst two canonical discriminant functions (percent of variance in parentheses). Centroid coordi- nates: A. yushanensis (4.493, –0.664), A. raritabulatus (–0.394, 1.897), A. waicunensis (–1.809, –1.342), A. oculiporoides (–0.592, 3.738) and A. maxima (–4.223, –0.790).

Discussion. The type specimens of Agetolitella waicunensis were collected from the Sanqushan Formation (Upper Ordovician), 3.5 km west of Tashan (Lin & Chow 1977). The corallite diameter reported for those specimens (3.5–5.2 mm; Lin & Chow 1977, pp. 148, 149) tends to be smaller than that for our coralla from the Xiazhen Formation at Zhuzhai but overlaps their range (D, 4.59–6.07 mm; Table 6). The corallite wall thickness and number of septa are similar between the types and our collection. Lin & Chow (1977) mentioned that the length of long septa in A. waicunensis (<0.88 mm) is less than half the corallite radius, which is also the case in our coralla (V3, Table 6; Fig. 5C). Septa in the types alternate in length, as in our specimens. Figures of A. waicunensis (Lin & Chow 1977) show that wall pores are very rare, as in some of our coralla. As explained previously (Discussion under Age- tolites), species with alternating long and short septa and with sporadic development of rare wall pores should be included in Agetolites, rather than Ageto- litella. Based on comparisons with the original description and illustrations, the coralla described here are identified as Agetolites waicunensis. In our collection, corallite size is variable. The average tabularium area (V1) and corallite perimeter (V7) are larger in interval A3 of sub-section ZU 1 than in A2, A3 of ZU 2, A5 and A6 (Table 9). In addition, the length of long septa (V3) is lower in interval A3 of Fig. 8. Cluster analysis of 108 coralla (identified by NIGPAS num- sub-section ZU 2 than in A2, A3 of ZU 1, A5 and A6 bers) and six type specimens (prefix IV) of Agetolites, based on the (Table 9). first three principal-components score matrix. An arrow on left side of Agetolites waicunensis is characterized by the short- specimen number indicates a type specimen (see Table 2). Dashed line est average septal lengths (V3, V4), in comparison with indicates recognition of five species at relative average distance 15 between clusters. the other four species of Agetolites recognized in the Xiazhen Formation at Zhuzhai: A. yushanensis, A. raritabulatus, A. oculiporoides and A. maxima (Table 6). ALCHERINGA ORDOVICIAN CORALS FROM CHINA 267

Fig. 10. A–I, Variation of nine morphological characters (V1–V9; see Table 3 for abbreviations) in ﬁve species of Agetolites (each corallum is represented by an empty circle; solid rhombuses and lines represent averages and ranges, respectively, for each species). 1, A. yushanensis;2,A. raritabulatus;3,A. waicunensis;4,A. oculiporoides;5,A. maxima.

The following species described from the Sanqushan 1963 Agetolites oculiporoides Lin; Lin in Yu & Zhang, Formation (Upper Ordovician) at Tashan in the JCY tri- p. 216, pl. 68, fig. 2a, b. angle (Fig. 1A) have corallite sizes that are similar to 1963 Agetolites huangi Lin; Lin in Yu & Zhang, A. waicunensis (Table 6): A. triangulatus Lin & Chow, pp. 216, 217, pl. 68, fig. 6a, b. 1977 (corallite diameter 3.5–5 mm; Lin & Chow 1977, 1977 Agetolites oculiporoides Lin; Lin in Lin & Chow, p. 138) and A. intermedius Lin & Chow, 1977 (corallite p. 136, pl. 22, fig. 1a, b. diameter 3.7–5 mm; Lin & Chow 1977, pp. 138, 139). 1977 Agetolites huangi Lin; Lin in Lin & Chow, However, A. waicunensis is distinct in having thinner p. 137, pl. 23, fig. 1a, b. common walls and more septa (V2, V6; Table 6) than – those species: A. triangulatus (wall thickness 0.3–0.5 Material. Nine coralla (NIGP PZ162483 162491) from mm, number of septa 16; Lin & Chow 1977, p. 138) intervals A1 and A2 at sub-section ZU 2, and A8, A10 and A. intermedius (wall thickness 0.4–0.6 mm, number and A12 at ZU 1 (Fig. 2; Table 1), Xiazhen Formation of septa 16; Lin & Chow 1977, pp. 138, 139). (Katian) at Zhuzhai, South China; paratype IV-3452 (Lin 1960), IV-3454 (holotype of A. huangi Lin, 1960), Agetolites oculiporoides Lin, 1960 (Fig. 5E, F) both from the Sanqushan Formation (Upper Ordovician) at Shiyanshan, South China. 1960 Agetolites oculiporoides Lin, p. 56, pl. I, figs 1a±c, 2a, b, pl. II, fig. 1a, b. Emended diagnosis. Corallites polygonal in transverse 1960 Agetolites huangi Lin, pp. 56, 57, pl. II, fig. 2a, b, section. Species average of corallite perimeter 16.21 pl. III, fig. 2a–c. mm, tabularium area 13.41 mm2, length of short septa 268 NING SUN et al. ALCHERINGA

Fig. 11. A–D, Selected bivariate plots of morphological characters (V1, V5, V7–V9; see Table 3 for abbreviations) for ﬁve species of Agetolites (r, Pearson correlation coefﬁcient). Each point on a plot represents a corallum.

0.43 mm, length of long septa 1.03 mm, ratio of aver- in A. oculiporoides (diameter 4–5.1 mm) than in A. age length of long septa to length of short septa 2.46, huangi (diameter 4.5–6 mm), these two species as origi- number of septa 18.37. Wall pores absent. nally described from the Sanqushan Formation at Shiyanshan and Tashan are remarkably similar in other Description. Corallites polygonal in transverse section, general morphological characteristics (Lin 1960). In our adult corallites hexagonal to octagonal (Fig. 5E). morphometric analysis, the type specimens of both spe- – Corallum averages of corallite perimeter 12.33 20.70 cies are grouped with our coralla from the Xiazhen For- – 2 mm, tabularium area 6.68 20.97 mm , length of septa mation at Zhuzhai (Figs 8, 9). Differences in the – 0.30 1.18 mm, ratio of average length of long septa to average values of quantitative morphological characters – – length of short septa 1.96 3.22, number of septa 17 20, (V1–V9) for the type specimens (Table 8) are consistent – wall thickness 0.23 0.31 mm (Table 6). Corner pores with variability in the range of values for coralla from commonly open to three corallites simultaneously, no different stratigraphic intervals in the Xiazhen Forma- wall pores evident (Fig. 5E). Tabulae mostly complete, tion (Table 9). Agetolites huangi is, therefore, consid- subhorizontal or slightly convex or concave, a few ered to be a junior synonym of A. oculiporoides, and incomplete (Fig. 5F). our coralla are identiﬁed as the latter species. In our collection, corallite size is quite variable. The Discussion. Except for more variable shapes of coral- average tabularium area (V1) and corallite perimeter lites in Agetolites oculiporoides (5–8 sides) than in A. (V7) are much larger in intervals A1 and A2 than in huangi (5–7 sides) and corallites that tend to be smaller ALCHERINGA ORDOVICIAN CORALS FROM CHINA 269

A8, A10 and A12 (Table 9). In addition, a higher ratio which is also evident in our coralla (V3, Table 6; of the length of long septa to short septa (V5) is evident Fig. 5G). Septa in the illustrated type specimen alternate in intervals A1 and A2 than in A8, A10 and A12 in length, as in our material. Rare wall pores occur in (Table 9). Nevertheless, plots based on the average val- the type and in some of our specimens. As explained ues of morphological characters for individual coralla previously (Discussion under Agetolites), species with assigned to this species show that there is continuity alternating long and short septa and with sporadic within the overall ranges of variability (Fig. 10). development of rare wall pores should be included in Agetolites oculiporoides is characterized by higher Agetolites, rather than Agetolitella. Based on compar- average common wall thickness (V2) and average isons with the original description and illustrations, the length of long septa (V3) than the other species of Age- coralla described here are identified as Agetolites tolites recognized in the Xiazhen Formation at Zhuzhai: maxima. A. yushanensis, A. raritabulatus, A. waicunensis and A. In our collection, corallite size is quite variable. In maxima (Table 6). Intraspecific variation of tabularium interval A1 at sub-section ZU 2 and A3 at ZU 1, coral- area is higher in A. oculiporoides than in those four lites are larger than in A2, A3 at ZU 2, and A5 species (Fig. 10A). (Table 9). In addition, a lower ratio of the length of long septa to length of short septa (V5) is evident in Agetolites maxima (Lin & Chow, 1977) (Fig. 5G, H) interval A3 at sub-section ZU 1 than in A1, A2, A3 at 1977 Agetolitella maxima Lin & Chow, p. 148, fig. 6a, ZU 2, and A5 (Table 9). b, pl. 31, fig. 3a, b. Agetolites maxima is characterized by higher average values of corallite size (V1, V7), number of septa (V6) Material. Eighteen coralla (NIGP PZ162492–162509) and ratios of corallite perimeter to septal lengths (V8, from intervals A1–A3 at sub-section ZU 2, and A3 and V9) than the other species of Agetolites recognized in A5 at ZU 1 (Fig. 2; Table 1), Xiazhen Formation the Xiazhen Formation at Zhuzhai: A. yushanensis, A. (Katian) at Zhuzhai, South China. raritabulatus, A. waicunensis and A. oculiporoides (Table 6). Agetolites sinensis Lin & Chow, 1977, from Emended diagnosis. Corallites sub-polygonal to polygo- the Sanqushan Formation at Tashan, has some morpho- nal in transverse section. Species average of corallite logical characters that are similar to A. maxima: corallite perimeter 20.35 mm, tabularium area 21.52 mm2, length diameters of 4–6 mm, wall thickness of 0.25 mm and of short septa 0.33 mm, length of long septa 0.76 mm, septa that are 0.67–1 mm long (Lin & Chow 1977, ratio of average length of long septa to length of short p. 143, pl. 27, fig. 1a–c). However, A. sinensis is dis- septa 2.30, number of septa 19.17. Rare wall pores in tinct in having sporadic development of septa. some coralla. Description. Corallites sub-polygonal to polygonal in Discussion and conclusions transverse section, adult corallites hexagonal to octagonal or even with nine or ten sides, shape of offsets In the JCY triangle region of South China, species from rounded or rectangular (Fig. 5G; Sun et al. 2014, figs the Sanqushan Formation that were assigned to 4a–o, 5a–l). Corallum averages of corallite perimeter Agetolitella by Lin & Chow (1977; see Table 7) are 18.57–22.71 mm, tabularium area 17.57–27.71 mm2, herein transferred to Agetolites (see Discussion under length of septa 0.29–0.86 mm, ratio of average length Agetolites in Systematic palaeontology). These species of long septa to length of short septa 2.01–2.59, number have alternating long and short septa, as characteristic of septa 18–21, wall thickness 0.18–0.28 mm (Table 6). of Agetolites, rather than septa of equal length as in Corner pores commonly open to three corallites simulta- Agetolitella. Lin & Chow (1977) reported that wall neously, wall pores rare in some, but not all, coralla pores are present in all of the species, as would be (Fig. 5G, arrow). Tabulae mostly complete, subhorizon- expected in Agetolitella. Their illustrations, however, tal or slightly convex or concave, few incomplete or show that the species range from having no wall pores, irregular (Fig. 5H). as would be expected in Agetolites, to rare wall pores in some coralla, to rare wall pores in all coralla. Discussion. The type specimen of Agetolitella maxima This suggests that the development of wall pores is was collected from the Sanqushan Formation (Upper intergradational between these genera. In two of the Ordovician), 3.5 km west of Tashan (Lin & Chow species described herein from the Xiazhen Formation at 1977). The corallite diameter reported for the species Zhuzhai (A. waicunensis, A. maxima), rare wall pores (4.5–6 mm; Lin & Chow 1977, p. 148) tends to be occur in some, but not all, of the coralla. In our opin- smaller than that for our coralla from the Xiazhen For- ion, the sporadic development of rare wall pores does mation at Zhuzhai (D, 5.91–7.23 mm; Table 6). The not justify the assignment of such species to Agetolitella corallite wall thickness and number of septa are similar rather than Agetolites. The possibility that Agetolitella is in the type and in our collection. Lin & Chow (1977) a junior synonym of Agetolites should be tested in a mentioned that the length of long septa in A. maxima future study by examining intra- and interspecific vari- (<0.9 mm) is less than two-fifths of the corallite radius, ability of septa (whether equal or alternating in length) 270 NING SUN et al. ALCHERINGA in material from other regions, including the type spe- highest average ratio of the length of long septa to cies of both genera. length of short septa. Agetolites oculiporoides differs Multivariate analysis was found to be effective in from the other species in having the highest intraspeci- discriminating species of Agetolites in this study. A fic variation of tabularium area (Figs 4, 5, 10). cluster analysis was conducted based on the first three Agetolites yushanensis commonly occurs in strata principal components for nine morphological characters, representing a wide spectrum of environments, includ- employing the unweighted pair-group method with ing low- to moderate-energy (intervals A6, A9 and A12 arithmetic average. Five morphospecies were recognized in sub-section ZU 1) and moderate- to high-energy from the cluster analysis. Their taxonomic validity as conditions (intervals A7, A8 and A10 in sub-section five species was verified by discriminant analysis, ZU 1; Table 1). With its relatively small coralla and descriptive statistics and bivariate plots, and the nature longer septa, A. yushanensis appears to have been of intra- and interspecific variation of the nine morpho- structurally stronger than the other four species. This logical characters was determined. The five species suggests that it was capable of remaining intact under were identified as A. yushanensis Lin, 1960, A. raritab- higher-energy conditions, perhaps contributing to its ulatus Lin, 1960, A. waicunensis (Lin & Chow, 1977), predominance over other species in the intervals that A. oculiporoides Lin, 1960 and A. maxima (Lin & include high-energy deposits. Among the five species of Chow, 1977). Lin (1960) stated that A. oculiporoides Agetolites, A. raritabulatus was widely distributed in a and A. huangi Lin, 1960 are remarkably similar in gen- wide spectrum of environments, including both low- to eral morphological characteristics, except for more vari- moderate-energy (intervals A4, A5, A9 and A12 in sub- able shapes of corallites in A. oculiporoides than in A. section ZU 1) and moderate- to high-energy conditions huangi and smaller corallites in A. oculiporoides than in (intervals A8 and A11 in sub-section ZU 1, and A2 and A. huangi. However, based on both qualitative examina- A3 in ZU 2). Agetolites raritabulatus appears to have tion of corallite shape (adult corallites hexagonal to adapted well to different environments. Agetolites octagonal) and quantitative examination of corallite size waicunensis, the most common species, was distributed (tabularium area 6.68–20.97 mm2, corallite perimeter in environments including low- to moderate-energy 12.33–20.70 mm; Fig. 10A, G; Tables 6, 8, 9), the (intervals A5 and A6 in sub-section ZU 1) and ranges of morphological characteristics of A. oculi- moderate- to high-energy conditions (intervals A2 and poroides encompass those for A. huangi and it is A3 in sub-section ZU 2). It appears to have been impossible to separate these species. Thus, A. huangi is capable of living in low- to high-energy conditions, but regarded as a junior synonym of A. oculiporoides. was especially dominant in moderate- to high-energy Coralla of Agetolites in the Xiazhen Formation at conditions. Agetolites oculiporoides inhabited both low- Zhuzhai were preserved in various conditions, which to moderate-energy (interval A12 in sub-section ZU 1, were determined mainly by lithology and depositional and A1 in ZU 2) and moderate- to high-energy condi- energy level. Coralla preserved in growth position were tions (intervals A8 and A10 in sub-section ZU 1, and usually contained in limestone deposited under low- to A2 in ZU 2). This species also occurred subordinate to moderate-energy conditions. High-energy conditions A. yushanensis in moderate-energy deposits. However, resulted in fragmentation and transportation of coralla. it appears that in such conditions, A. oculiporoides was The size of corallites and septal length are considered disadvantaged compared with A. yushanensis (intervals to discriminate between Agetolites species. A8 and A10 in sub-section ZU 1). Agetolites maxima The apparent high diversity of Agetolites species in lived in a wide spectrum of environments, including South China is partly a consequence of taxonomic split- both low- to moderate-energy (interval A5 in sub- ting by previous workers (e.g., Lin & Chow 1977), and section ZU 1, and A1 in ZU 2) and moderate- to high- is also considered partly a result of high speciation rates energy conditions (intervals A2 and A3 in sub-section and endemism of the agetolitids. Ordovician shallow- ZU 2). With its relatively large coralla and short septa, water, marine invertebrate communities in China tend to A. maxima appears to have favoured low-energy be geographically restricted and highly endemic, as environments in which it could remain intact. suggested by Rong et al.(1999) and demonstrated for brachiopods (Zhan & Cocks 1998) and graptolites (Chen et al. 2009). In each of the five Agetolites species Acknowledgements at Zhuzhai, morphological characters related to corallite Funding from the National Research Foundation of Korea, size, septal length and number of septa show some through research grant no. NRF-2013R1A2A2A01067612 differences among stratigraphic intervals in the Xiazhen and NRF-2014K2A2A2000787, is acknowledged. We are Formation (Table 9). In general, A. yushanensis is indebted to Liming Guan (Beijing Snow Birch Petroleum characterized by relatively small corallite size and well- Technology Company Limited) for assistance during developed septa, whereas A. maxima has relatively large fieldwork. We thank two anonymous reviewers and corallite size. Agetolites waicunensis has comparatively the editor, Stephen McLoughlin, for providing helpful short septal length, whereas A. raritabulatus has the comments. ALCHERINGA ORDOVICIAN CORALS FROM CHINA 271

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Specimens V1 V2 V3 V4 V5 V6 V7 V8 V9 162402 6.0800 0.2811 0.8903 0.5800 1.5350 16.6000 12.3000 13.8156 21.2069 162403 4.0200 0.2500 0.9077 0.4716 1.9247 16.0000 8.8600 9.7609 18.7871 162404 6.2800 0.2900 0.9257 0.5545 1.6694 18.0000 11.6300 12.5635 20.9739 162405 3.0800 0.2442 0.9211 0.4962 1.8563 16.0000 8.3700 9.0870 16.8682 162406 6.2700 0.2900 0.9065 0.5988 1.5139 18.3300 11.9100 13.1384 19.8898 162407 5.7200 0.2400 0.9422 0.4562 2.0653 16.0000 10.7500 11.4095 23.5642 162408 5.0300 0.2400 0.9216 0.4883 1.8874 17.6700 10.3700 11.2522 21.2369 162409 6.1500 0.2666 0.9122 0.5099 1.7890 16.0000 11.2500 12.3328 22.0631 162410 4.7700 0.2500 0.9120 0.5421 1.6823 16.0000 9.6200 10.5482 17.7458 162411 5.6200 0.2824 0.9200 0.5459 1.6853 16.0000 10.8600 11.8043 19.8938 162412 6.4000 0.2458 0.8999 0.5787 1.5550 16.3300 11.8300 13.1459 20.4424 162413 7.5800 0.2400 0.9783 0.6892 1.4195 17.8000 13.5600 13.8608 19.6750 162414 6.9900 0.2300 0.9628 0.5660 1.7011 16.5000 12.6300 13.1180 22.3145 162415 7.4800 0.2625 0.9437 0.5200 1.8148 16.0000 12.8500 13.6166 24.7115 162416 7.2100 0.2800 1.0973 0.6200 1.7698 16.0000 13.3000 12.1207 21.4516 162417 5.8300 0.2697 0.9734 0.5655 1.7213 16.7500 12.0800 12.4101 21.3616 162418 7.1100 0.2600 1.0403 0.6400 1.6255 18.7500 13.0100 12.5060 20.3281 162419 5.7100 0.2676 0.9050 0.5143 1.7597 16.0000 12.4200 13.7238 24.1493 162420 7.4000 0.2700 1.0127 0.6554 1.5452 17.2000 13.8600 13.6862 21.1474 162421 4.1500 0.2500 0.9195 0.4700 1.9564 16.0000 10.4300 11.3431 22.1915 162422 5.4700 0.2300 0.9777 0.5000 1.9554 16.0000 11.3800 11.6396 22.7600 162423 4.3900 0.2200 0.8947 0.5353 1.6714 16.0000 9.9600 11.1322 18.6064 162424 3.4700 0.2500 0.9300 0.5800 1.6034 15.4000 9.0300 9.7097 15.5690 162425 6.6700 0.2600 1.0087 0.6200 1.6269 16.0000 12.2700 12.1642 19.7903 162426 4.7400 0.2300 0.9112 0.4899 1.8600 16.0000 11.2200 12.3134 22.9026 162427 6.4800 0.2800 0.9800 0.6100 1.6066 15.8000 12.2400 12.4898 20.0656 162428 8.5700 0.2600 1.0529 0.5939 1.7729 16.7500 13.5900 12.9072 22.8826 162429 4.2700 0.2712 0.9136 0.5400 1.6919 16.0000 10.5500 11.5477 19.5370 162430 5.5800 0.2500 0.9215 0.4755 1.9380 16.0000 13.0900 14.2051 27.5289 162431 5.8700 0.2723 0.9400 0.5600 1.6786 15.8000 12.7600 13.5745 22.7857 IV-3463 6.2100 0.2958 0.9960 0.5313 1.8746 16.5000 12.1500 12.1988 22.8684

IV-3464 4.4700 0.3243 0.9095 0.5308 1.7135 15.6000 9.2269 10.1450 17.3830 IV-3465 5.5443 0.3100 0.9365 0.5544 1.6892 15.6700 12.2712 13.1033 22.1342 162432 12.7700 0.2265 0.8894 0.3025 2.9402 17.6000 16.0882 18.0888 53.1841 162433 11.7700 0.2396 0.9118 0.3000 3.0393 18.0000 15.5000 16.9993 51.6667 162434 14.3700 0.2300 0.9538 0.3000 3.1793 18.0000 16.7000 17.5089 55.6667 162435 13.4600 0.2186 0.8240 0.3000 2.7467 18.6000 16.4200 19.9272 54.7333 162436 10.5600 0.2200 0.7992 0.2500 3.1968 18.0000 15.0000 18.7688 60.0000 162437 12.1900 0.2193 0.8235 0.2800 2.9411 18.8000 15.8500 19.2471 56.6071 162438 9.9200 0.2775 0.9848 0.3966 2.4831 18.0000 14.0100 14.2262 35.3253 162439 9.3300 0.2300 0.9976 0.4200 2.3752 17.8000 14.9100 14.9459 35.5000 162440 9.1600 0.2630 0.9716 0.4000 2.4290 16.0000 13.9800 14.3886 34.9500 162441 8.6100 0.2900 0.9284 0.3900 2.3805 18.0000 14.3200 15.4244 36.7179 162442 9.9300 0.2368 0.9557 0.4303 2.2210 16.0000 14.7000 15.3814 34.1622 162443 11.4707 0.2711 0.8654 0.3800 2.2774 18.4000 16.4100 18.9623 43.1842 162444 11.8800 0.2500 0.9879 0.3900 2.5331 17.4000 14.6300 14.8092 37.5128 162445 15.3600 0.2200 0.9078 0.3800 2.3889 18.0000 17.4100 19.1782 45.8158 162446 13.5100 0.1998 0.9655 0.3600 2.6819 20.0000 14.9200 15.4531 41.4444 162447 11.2200 0.2200 0.9774 0.3600 2.7150 18.0000 14.8200 15.1627 41.1667 162448 14.4700 0.2127 0.9605 0.4155 2.3117 18.0000 15.6500 16.2936 37.6655 162449 9.3700 0.2485 0.7943 0.3795 2.0930 19.0000 14.0000 17.6256 36.8906 162450 8.5600 0.2629 0.7712 0.2400 3.2133 18.2500 13.6100 17.6478 56.7083 IV-3466 7.8300 0.2500 0.8614 0.4428 1.9453 19.0000 13.3700 15.5212 30.1942 162451 18.3700 0.1784 0.8100 0.3300 2.4545 18.0000 18.5700 22.9259 56.2727 162452 17.7499 0.1699 0.6800 0.2200 3.0909 18.0000 18.3800 27.0294 83.5455 162453 16.0400 0.2398 0.7689 0.2800 2.7461 18.0000 17.0100 22.1225 60.7500 162454 10.6500 0.2507 0.7600 0.3058 2.4853 18.0000 14.7800 19.4474 48.3322 162455 14.7200 0.2364 0.7600 0.3000 2.5333 18.0000 15.8200 20.8158 52.7333 162456 13.8100 0.2107 0.7562 0.3100 2.4394 18.0000 15.8400 20.9468 51.0968 162457 12.8300 0.2200 0.7511 0.2900 2.5900 18.0000 16.1800 21.5417 55.7931 162458 12.7900 0.2900 0.7189 0.3009 2.3892 18.0000 15.6500 21.7694 52.0106 162459 11.8400 0.2157 0.7000 0.2500 2.8000 18.8000 15.3700 21.9571 61.4800 162460 12.8900 0.2616 0.6700 0.2300 2.9130 18.0000 15.6900 23.4179 68.2174 162461 12.7300 0.2424 0.7800 0.2909 2.6813 18.0000 15.8300 20.2949 54.4173

(Continued) 274 NING SUN et al. ALCHERINGA

Appendix 1. (Continued). Specimens V1 V2 V3 V4 V5 V6 V7 V8 V9 162462 16.3100 0.2460 0.7128 0.2875 2.4793 18.0000 17.4700 24.5090 60.7652 162463 16.1600 0.2400 0.8025 0.4300 1.8663 18.0000 19.0500 23.7383 44.3023 162464 13.8800 0.2600 0.7740 0.3873 1.9985 18.0000 16.5000 21.3178 42.6026 162465 16.7600 0.2584 0.6858 0.3268 2.0985 19.0000 17.2900 25.2114 52.9070 162466 13.9000 0.2691 0.7834 0.3992 1.9624 17.0000 16.5000 21.0620 41.3327 162467 13.1800 0.1918 0.8563 0.3900 2.1956 20.0000 16.5400 19.3157 42.4103 162468 13.1000 0.1813 0.8108 0.3651 2.2208 18.0000 15.2900 18.8579 41.8789 162469 14.5000 0.2372 0.7828 0.3150 2.4851 18.6000 16.7600 21.4103 53.2063 162470 10.2400 0.2900 0.7600 0.3700 2.0541 17.2000 15.8000 20.7895 42.7027 162471 11.6800 0.2695 0.7867 0.3982 1.9756 17.2000 15.6100 19.8424 39.2014 162472 16.6400 0.1884 0.6500 0.2700 2.4074 20.0000 17.3700 26.7231 64.3333 162473 19.3500 0.1635 0.6800 0.2800 2.4286 20.0000 19.0600 28.0294 68.0714 162474 17.5519 0.2187 0.7014 0.3015 2.3264 19.3300 18.6700 26.6182 61.9237 162475 11.6302 0.2829 0.7400 0.3500 2.1143 17.2000 14.8700 20.0946 42.4857 162476 19.5500 0.1716 0.7500 0.3700 2.0270 20.0000 18.3100 24.4133 49.4865 162477 17.6201 0.1800 0.6516 0.2312 2.8183 18.0000 17.9300 27.5169 77.5519 162478 11.4200 0.2717 0.7426 0.3700 2.0070 17.7500 15.8000 21.2766 42.7027 162479 15.5270 0.2117 0.6225 0.3002 2.0736 18.0000 17.1162 27.4959 57.0160 162480 14.8171 0.2000 0.6931 0.2529 2.7406 17.5000 16.7041 24.1006 66.0502 162481 12.9331 0.1993 0.6965 0.3751 1.8568 18.0000 15.8500 22.7566 42.2554 162482 11.0267 0.2701 0.6915 0.3598 1.9219 17.6000 14.4200 20.8532 40.0778 162483 10.6600 0.2900 1.0852 0.5400 2.0096 17.2000 14.4000 13.2694 26.6667 162484 9.9900 0.2875 0.9948 0.4214 2.3607 18.6000 14.3849 14.4601 34.1360 162485 6.6800 0.3000 1.0021 0.5100 1.9649 19.0000 12.3300 12.3042 24.1765 162486 9.3700 0.2700 1.1073 0.5200 2.1294 17.4000 14.4800 13.0769 27.8462 162487 20.9700 0.2555 0.8891 0.3000 2.9637 18.0000 20.7000 23.2820 69.0000 162488 16.7800 0.2300 1.1762 0.4500 2.6138 18.6000 18.4500 15.6861 41.0000 162489 18.0200 0.2600 0.9871 0.3400 2.9032 18.0000 18.3300 18.5695 53.9118 162490 14.9100 0.2497 1.0474 0.4200 2.4938 20.0000 16.3900 15.6483 39.0238 162491 18.5100 0.2312 1.0303 0.3200 3.2197 18.0000 18.1900 17.6551 56.8438 IV-3452 9.1094 0.3068 0.9461 0.4295 2.2028 18.0000 14.9935 15.8477 34.9092 IV-3454 12.5105 0.2800 1.0919 0.4870 2.2421 19.2500 15.6487 14.3316 32.1329 162492 25.8300 0.2500 0.8311 0.3958 2.0998 19.0000 21.6700 26.0739 54.7499 162493 22.4100 0.2400 0.8631 0.4300 2.0072 18.0000 21.1100 24.4583 49.0930 162494 18.7200 0.2811 0.7956 0.3300 2.4109 18.0000 18.7700 23.5923 56.8788 162495 20.5500 0.2402 0.6900 0.3144 2.1947 20.0000 20.0384 29.0412 63.7354 162496 22.8800 0.2319 0.7347 0.2950 2.4905 19.2500 21.9200 29.8353 74.3051 162497 21.4400 0.2400 0.7076 0.3491 2.0269 20.0000 20.7900 29.3810 59.5531 162498 19.7900 0.2100 0.8371 0.3814 2.1948 20.0000 19.3300 23.0916 50.6817 162499 27.7100 0.2329 0.6900 0.3233 2.1342 18.0000 22.6400 32.8116 70.0278 162500 25.5800 0.2447 0.8201 0.3612 2.2705 18.0000 21.6200 26.3626 59.8560 162501 27.3223 0.2529 0.6707 0.3152 2.1279 18.0000 22.7000 33.8452 72.0178 162502 17.9900 0.2625 0.7996 0.3092 2.5860 18.0000 19.0400 23.8119 61.5783 162503 26.9800 0.2280 0.6700 0.2864 2.3394 18.0000 22.7100 33.8955 79.2947 162504 17.7866 0.2400 0.7478 0.3161 2.3657 19.3300 18.8500 25.2073 59.6330 162505 19.0700 0.2100 0.7600 0.3136 2.4235 20.0000 19.0900 25.1184 60.8737 162506 17.6870 0.2273 0.7296 0.3137 2.3258 20.4000 18.7000 25.6305 59.6111 162507 19.5900 0.1814 0.7700 0.3200 2.4063 20.0000 19.5100 25.3377 60.9688 162508 18.3700 0.2112 0.7700 0.3000 2.5667 20.0000 19.2200 24.9610 64.0667 162509 17.5702 0.2400 0.7419 0.3000 2.4730 21.0000 18.5700 25.0303 61.9000

Appendix 1. Raw data matrix for Agetolites from South China: 108 coralla from the Xiazhen Formation (Upper Ordovician) at Zhuzhai (identiﬁed by NIGP PZ numbers) and six type specimens from the Upper Ordovician at Shiyanshan (preﬁx IV; Geological Museum of China) by nine morphological characters (V1–V9; see Table 3 for abbreviations and units).