Futakami and Haggart—early Albian (Early Cretaceous) douvilleiceratid ammonites


islands in Bearskin Bay (Haggart, 2004). The Albian section at Bearskin Bay is perhaps one of the best biostratigraphic reference sections for the Albian stage within the North Pacific region. Lowermost Cretaceous strata exposed at Bearskin Bay con-


sist primarily of conglomerate, sandstone, and alternating sand- stone and siltstone. Collectively, these strata comprise the Haida Formation of the Queen Charlotte Group, and range in age from late early Albian to early late Albian (McLearn, 1972; Haggart, 1986, 1991). The Haida Formation grades upward into muddy siltstone and silty mudstone and shale of the informal Bearskin Bay formation, whichrangesinage fromlatelate Albian tolate early Turonian (Haggart, 1986, 2004) (Fig. 1.3). The Bearskin Bay formation is in turn overlain, apparently conformably, by the poorly-fossiliferous Honna Formation (Haggart, 1991). In addition to its relatively complete succession and simple


structure, the Haida Formation displays an abundant and diverse molluscan fauna, including ammonites, bivalves, and gastro- pods. A basic biostratigraphic framework for the formation was established by McLearn (1972) and Jeletzky (1977), who recognized four local ammonite zones within the formation on Haida Gwaii. In ascending stratigraphic order these are: (1) the Leconteites lecontei Zone (=Leymeriella (L.) tardefurcata Zone in ammonite standard zonation of Reboulet et al., 2011, lower lower Albian); (2) the Brewericeras hulenense Zone (=Douvilleiceras mammillatum Zone, upper lower Albian); (3) the Cleoniceras (Grycia) perezianum Zone (=Hoplites dentatus ~ Euhoplites lautus zones, middle Albian); and (4) the Mortoniceras - Desmoceras (Pseudouhligella) dawsoni Zone (Dipoloceras cristatum ~ Arrhaphoceras briacensis zones, upper Albian). The Haida Formation at Skidegate Inlet, how- ever, lacks the basal Albian Leconteites lecontei Zone (Fig. 1.3). Douvilleiceras spiniferum (Whiteaves) is found commonly


within a limited geographical and stratigraphical range in the upper lower Albian Brewericeras hulenense Zone on Lina and Maude islands (Fig. 1.2), and the northern part of Moresby Island (McLearn, 1972). In addition to D. spiniferum, we recognize several additional species of the genus Douvilleiceras from Haida Gwaii.All of these douvilleiceratidswere obtained fromcalcareous concretions rich with the ammonite Brewericeras hulenense (Anderson, 1938) and plant fragments.


Systematic paleontology


Institutional abbreviations.—BM = Natural History Museum, London; GSC = Geological Survey of Canada, Ottawa; GSM = Geological Survey Museum, London.


Dimensions.—All measurements are given in millimeters. The following abbreviations are used for morphological features: D = specimen diameter; B = whorl breadth; H = whorl height; U = umbilical width; NR = number of ribs per whorl; NT = number of tubercles on each rib.


Sutural terminology.—Sutural terminology follows the usage of Wedekind (1916) as augmented by Kullmann and Wiedmann (1970), Wiedmann and Kullmann (1981), and Korn et al. (2003): I = internal lobe; U = umbilical lobe; A = lateral lobe; E = external lobe.


Order Ammonoidea Zittel, 1884 Suborder Ancyloceratina Wiedmann, 1966


Superfamily Douvilleiceratoidea Parona and Bonarelli, 1897 Family Douvilleiceratidae Parona and Bonarelli, 1897


Subfamily Douvilleiceratinae Parona and Bonarelli, 1897 Genus Douvilleiceras de Grossouvre, 1894


Douvilleiceras mammillatum (Schlotheim, 1813) Figures 2, 3


1962 Douvilleiceras mammillatum; Casey, p. 265, pl. 40, fig. 4, pl. 41, figs. 4a–b, pl. 42, figs. 6, 9a–b, 10a–b, text-figs. 94, 102a–b [with synonymy].


1962 Douvilleiceras mammillatum var. aequinodum; Casey,


p. 271, pl. 40, fig. 5, pl. 41, figs. 5–7, pl. 42, figs. 10a–b, text-figs. 94a–c, 95a–b, 102d, 103a–b.


1962 Douvilleiceras mammillatum var. praecox; Casey, p. 272, pl. 41, figs. 8a–b, text-figs. 94d–e, 102c.


1962 Douvilleiceras monile; Casey, p. 284, pl. 41, figs. 2a–b, pl. 42, fig. 5, text-fig. 102e.


1963 Douvilleiceras mammillatum; Collignon, p. 109, pl. 283, figs. 1238–1239, 1241, pl. 284, fig. 1242.


? 1963 Douvilleiceras albense; Collignon, p. 112, pl. 284, fig. 1243.


1969 Douvilleiceras mammillatum; Obata, p. 172–174, pl. 19, figs. 3, 5.


1972 Douvilleiceras spiniferum; McLearn, p. 62 (pars), pl. 10, figs. 3A–C.


1979 Douvilleiceras mammillatum mammillatum; Destombes, p. 69, pl. 4–21, fig. 1.


1979 Douvilleiceras mammillatum


Destombes, p. 71, pl. 4–4, fig. 1, pl. 4–5, fig. 2, pl. 4–21, fig. 2.


var.


1979 Douvilleiceras perchoisense; Destombes, p. 72, pl. 4–4, figs. 2a, b.


1983 Douvilleiceras aequinodum; Weidich et al., p. 566, pl. 2, fig. 6.


1990 Douvilleiceras mammillatum; Marcinowski and Wiedmann,p.51, pl.7, figs.5,6.


? 2005 Douvilleiceras cf. mammillatum; Myczyński and Iturralde-Vinent, p. 792, figs. 3–9, 5.1, 2, 3.


2005 Douvilleiceras mammillatum; Prins, p. 31, CP46. 2008 Douvilleiceras mammillatum aequinodum; Latil, p. 257, pl. 2, figs. 4, 5.


2010 Douvilleiceras mammillatum; Courville and Lebrun, p. 28, pl. 1, figs. E, F.


2010 Douvilleiceras monile; Courville and Lebrun, p. 28, pl. 2, fig. R, pl. 6, fig. A.


Type.—Neotype,BMC12491, designated by Casey (1962, pl. 41, figs. 4a-b, text-fig. 102a), Folkestone Beds, main mammillatum bed, Copt Point, Folkestone, Kent (Coll. F. G. H. Price).


Description.—The coiling is moderately involute and the umbilicus is moderately wide, with U/D = 0.35. The whorl is depressed (Fig. 3). Multituberculate ribs on the outer whorl are rectiradiate and separated by interspaces a little wider


aequinodum;


1979 Douvilleiceras mammillatum var. praecox; Destombes, p. 71, pl. 4–21, fig. 3.


45


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