search.noResults

search.searching

note.createNoteMessage

search.noResults

search.searching

orderForm.title

orderForm.productCode
orderForm.description
orderForm.quantity
orderForm.itemPrice
orderForm.price
orderForm.totalPrice
orderForm.deliveryDetails.billingAddress
orderForm.deliveryDetails.deliveryAddress
orderForm.noItems
786


Journal of Paleontology 89(5):768–790


stratigraphically important in North China (An et al., 1983; An and Zheng, 1990;Wang et al., 2014).


Plectodina onychodenta An and Xu, 1983 Figure 7.19–7.22


1983 Plectodina onychodonta An and Xu, p. 121, pl. 23, figs. 1–16, pl. 24, figs. 1–15, pl. 25, fig. 4. [partim] non pl. 23, figs. 1–5, pl. 25, fig. 7.


1987 Plectodina onychodonta; Pei and Cai, p. 87, pl. 7, figs. 1–10,12–13,15–16. [partim] non pl. 7, figs. 5–7,9


2006 Plectodina onychodonta; Agematsu et al., 2006, fig. 7:13.


2014 Plectodina onychodonta; Wang et al., p. 8, pl. 2, fig. 11–13. [partim] non pl. 2, figs. 11–12.


Description.—The Pa element is prioniodiniform. In the present study, one adult and two juvenile Pa specimens are illustrated (Figure 7.19–7.21). The adult one (Figure 7.19) is robust, with a procline cusp and a slightly bowed aboral outline; the anterior and posterior processes are of unequal length; denticles on the shorter anterior process are closely spaced and basally confluent; the longer posterior process bears separated denticles; basal cavity is fairly inflated under the cusp, and ante- roposteriorly and evenly extends below the two processes. Both juvenile Pa elements (figure 7.20, 7.21) have rather straight aboral outlines and scarcely inflated basal cavities. The Sa element (figure 7.22) is also a juvenile form, the two lateral denticulated processes form a very acutely arched basal outline.


Material.—Ten specimens (Table 1). Occurrence.—W-6-1, W-7-1, W-8-1.


Remarks.—An and Xu (in An et al., 1983) recognized six elements of this species: prioniodiniform (= Pa), dichognathi- form (= Pb), cyrtoniodontiform (= M), trichonodelliform (= Sa), zygognathiform (= Sb), and subcordylodontiform elements. However, their subcordylodontiform elements (pl. 23, Figs. 1–5) and a dichognathiform element (pl. 25, Fig. 7) are identical to the Sc and Pa elements of Phragmodus polonicus respectively, and the present authors prefer to assign them to P. polonicus. Several characteristics of our specimens, such as limited inflation of basal cavity under the cusp and slightly bowed aboral outline of Pa element, agree with the descriptions by An et al. (1983) and Wang et al. (2014). These characters also indicate that the specimens differ from the congeneric species in North America (Sweet, 1981), such as P. aculeata (Stauffer, 1930), P. tenuis (Branson and Mehl, 1933), P. aculeatoides Sweet, 1979, and P. florida Sweet, 1979.


Genus Pygodus Lamont and Lindström, 1957


Type species.—Pygodus anserinus Lindström, 1957.


Lamont and


Remarks.—The seximembrate apparatus of Pygodus that consists of pygodontiform (modified stelliscaphate Pa)


and haddingodontiform (pastinate Pb) elements and four types of ramiform (alate Sa, tertiopedate Sb, bipennate Sc and quadriramate Sd) elements has been generally accepted (e.g. McCracken, 1991; Zhang, 1998a; Zhen et al., 2009, 2011b). Dzik (1994) suggested the presence of a possible geniculate M element in the species apparatus of Pygodus, but such an element has not yet been reported in other collections.


Pygodus lunnensis Zhang, 1998c Figure 9.1, 9.2, 9.10


1998c Pygodus lunnensis Zhang, p. 95, pl. 1, figs. 12–16. [see for synonymy]


1999 Polonodus sp. A Ottone, pl. 6, figs. 6,8–9. 2013 Pygodus lunnensis; Agematsu, fig. 4:10. 2013 Polonodus sp. A Wang et al., fig. 14I.


Description.—The broken Pa elements (Figure 9.1, 9.2) have anterior, posterolateral, and anterolateral processes. The surface of the platform is ornamented with contoured ridges. The ante- rior and posterolateral processes are close and confluent. The anterolateral process produces a secondary anterolateral process on the edge of its platform, and is wider than the other processes. The concavity between the postero-lateral and anterior processes is deeper than that between the anterolateral and anterior processes. The Pb element (Figure 9.10) has an erect cusp, and weakly denticulated anterolateral, anterior, and posterior processes.


Material.—Three specimens (Table 1). Occurrence.—W-6-1.


Remarks.—The two broken Pa and one complete Pb elements in our collections display the main characters of Pygodus lunnensis as described by Zhang (1998c). Bergström (1983) discussed the evolution of Pygodus species and regarded P. lunnensis (=P.? n. sp. in Bergström, 1983) as the pioneer species of this genus. Stouge and Bagnoli (1999) postulated that Pygodus might have evolved from Dzikodus. Although Rasmussen (2001) considered that P. lunnensis is more similar to Polonodus, the taxon itself and the eponymous subzone have been widely adopted (e.g. Löfgren, 2003, 2004; Bergström, 2007b; Agematsu et al., 2013).


Genus Spinodus Dzik, 1976 Type species.—Polygnathus spinatus Hadding, 1913.


Remarks.—Dzik (1994) suggested Spinodus might be closely related to Erraticodon or Erismodus, but distributed in relatively deeper water environments. As noted by Zhang (1998a), Spinodus is a geographically very widespread genus and its species appear to occur mainly in continental margin and basin deeper-water sediments. Therefore, this genus has been considered as a good depth indicator. Species of Spinodus have been interpreted to consist of a seximembrate (or likely septimembrate) ramiform-ramiform species apparatus


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164  |  Page 165  |  Page 166  |  Page 167  |  Page 168  |  Page 169  |  Page 170  |  Page 171  |  Page 172  |  Page 173  |  Page 174  |  Page 175  |  Page 176  |  Page 177  |  Page 178  |  Page 179  |  Page 180  |  Page 181  |  Page 182  |  Page 183  |  Page 184  |  Page 185  |  Page 186  |  Page 187  |  Page 188  |  Page 189  |  Page 190  |  Page 191  |  Page 192  |  Page 193  |  Page 194  |  Page 195  |  Page 196  |  Page 197  |  Page 198  |  Page 199  |  Page 200  |  Page 201  |  Page 202  |  Page 203  |  Page 204  |  Page 205  |  Page 206  |  Page 207  |  Page 208  |  Page 209  |  Page 210  |  Page 211  |  Page 212