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Baculites anceps Lamarck 1822 from: Ward, P.D..Kennedy, W.J.. (1993): Maastrichtian Ammonites from the Biscay Region (France, Spain) . Memoir (The Paleontological Society), Journal of Paleontology34 (Supplement to Vol. 67)(5) p. 1-58
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Species Baculites anceps Lamarck 1822



Diagnosis / Definition:
Kennedy (1986):
Material. The several hundred specimens in the repositories listed on p. 27 are not noted separately here. Localities given are 'Normandy', 'Manche', Fresville, Valognes, Ste Colombe, Picauville, Orglandes, Port Filiolet, Nehou, Bonneville, and Golleville. Discussion. Howarth (1965) has provided a full and comprehensive description and discussion of B. anceps, to which the reader is referred. The characteristic features ofthe species are the tear-shaped whorl section (text-fig. 3E-H), the acute, sharp venter flanked by grooves (PI. 11, fig. 12; PI. 12, figs. 8 and 11), plus strongly projected ventrolateral ribbing such that the aperture possessed a very long rostrum. As with the material studied by Howarth, an examination of hundreds of specimens at all growth stages shows a predominance of feebly ornamented to near smooth individuals, some with lateral grooves, and a paucity ofribbed forms (Howarth 1965, pI. 6, fig. 1). Because there are so few examples with phragmocone and body-chamber associated it is difficult to assess the state of maturity ofmost specimens, but body-chambers reach a much larger size than those illustrated by Howarth; Plate 12, figs. 7 and 8 show the largest body-chamber seen which is incomplete at a whorl height of , 34 mm. I would also note the marked curvature of some specimens (PI. 11, fig. 13). B. carinatus Binkhorst, 1861 (p. 43, pI. 5d, fig. 2) (not Morton) from Mont St Pierre, Maastricht, is an Upper Maastrichtian form with a curious, tear-shaped section and ventral ribs only. I was unable to find the holotype in the Binkhorst Collection during a visit to the Museum für Naturkunde, East Berlin, in December 1983. B. valognensis J. Böhm, 1891 (p. 50, pI. 1, fig. 13) is based on a fragment only from Siegsdorf, Oberbayern, and is best regarded as a nomen dubium. The specimens from the Calcaire cl. Baculites named B. anceps valognensis by Nowak (1908, p. 335, pI. 14, figs. 6 and 7; text¬figs. 1-4 on p. 331 and 6,7,9,12 on p. 337) are within the limits ofthis species, as Howarth noted. B. a. leopoliensis Nowak, 1908 (p. 328, pl. 14, figs. 1-5, 10, 11) is a much larger species with strong crescentic ribs on the flanks and persistent secondary ribs on the venter.
Ward & Kennedy (1993):
Description and discussion. - As noted above, we are only able to refer ribbed specimens to Baculites anceps with any confidence, as whorl section, not determinable in the Biscay material, is needed to distinguish between feebly ornamented to smooth B. anceps and B. vertebralis. Whorls expand slowly. Flanks ornamented by strong ribs, 2-3 in a distance equal to whorl height. They are concave and strong on dorsal two-thirds of flank but decline on ventral third, where they sweep forwards to intersect line of venter at acute angle.
Discussion / Comments:
Ward & Kennedy (1993):
Type. - Neotype, designated by Howarth, 1965, p. 365, Pl. 5, fig. 5, is BMNH 32573, from the Calcaire à Baculites of "Normandy." Occurrence. - In the Biscay sections this taxon is restricted to Member I (lower Maastrichtian). Elsewhere, the species is upper Maastrichtian where well dated, with records from northern Spain, the Calcaire à Baculites of the Cotentin Peninsula, Manche, France, the Netherlands, Denmark, and the former USSR.
Synonym list:
Kennedy (1986):
1822 Baculites anceps Lamarck. - Lamarck : p.648
1885 Baculites schlüteri Moberg. - Moberg : p.40 pl. 4, fig. 13 only
non 1963 Baculites cf. anceps Lamarck. - Young : p.42 pl. 2, figs. 18, 20-22
non 1964 Baculites anceps Lamarck. - Giers : p.257 text-fig. 3
1965 Baculites anceps Lamarck. - Howarth : p.363 pl. 4, fig. 4; pl. 5; pl. 6, figs. 1-5; text-figs. 2, 3, 5-12 (with synonymy)
non 1976 Baculites anceps Lamarck. - ATABEKIAN & Khakhimov : p.94 pl. 2, figs. 3 and 4; pl. 11, figs. 8-10
1979 Baculites valognensis Boehm. - BIRKELUND : p.53
? 1982 Baculites anceps Lamarck. - Martinez : p.169 pl. 30, figs. 1 and 2
1986 Baculites anceps Lamarck. - Kennedy : p.58 pl. 11, figs. 12-14; pl. 12, figs. 7-11; text-figs. 3E-H, 7A-C
Ward & Kennedy (1993):
1822 Baculites anceps Lamarck. - Lamarck : p.648
1986 Baculites anceps Lamarck. - Kennedy : p.58 pl. 11, fig. 12-14; pl. 12, fig. 7-11; text-fig. 3E-H, 7A-C
1986 Baculites anceps Lamarck. - Kennedy : fig. 10N-O
1987 Baculites anceps Lamarck. - Kennedy : p.189 pl. 20, fig. 2; pl. 28, fig. 3, 11-13, 19-23; text-fig. 11C, D (with full synonymy)
1993 Baculites anceps Lamarck. - Ward & Kennedy : p.52 fig. 45.2
Stratigraphy - relative ages:
upper Maastrichtian - Maastrichtian: Kennedy (1986)
upper Maastrichtian: Ward & Kennedy (1993)
References:

Lamarck,J.P.B.A.D.M.D.. (1822):
Histoire naturelle des Animaux sans vertebres. Vol. 7 p. 711 pp.

Moberg,J.C.. (1885):
Cephalopoderna i Sveriges Kritsystem. . H. Sver. geol. Unders. Afh. Vol. 73 p. 1-63

Young,K.. (1963):
Upper Cretaceous ammonites from the Gulf Coast of the United States . Univ. Tex. Bull. Vol. 6304 p. ix+373 pp.

Giers,R.. (1964):
Die Grossfauna der Mukronatenkreide (unteres Obercampan) im östlichen Münsterland . Fortsehr. Geol. Rheinld Westf. Vol. 7 p. 213-294

Howarth,M.K.. (1965):
Cretaceous ammonites and nautiloids from Angola . Bull. Br. Mus. nat. Hist. (Geol.) Vol. 10 p. 335-415

ATABEKIAN,A.A.. and Khakhimov,F.K.. (1976):
Campanian and Maastrichtian ammonites in Central Asia. . Trudy Inst. Geol. Dushanbe [In Russian.] p. 146 pp.

BIRKELUND,T.. (1979):
The last Maastrichian ammonites.
In: Cretaceous-Tertiary Boundary, The Maastrichtian and Danian of Denmark Eds: Events Symposium, 1.. p. 210 pp.

Martinez,R.. (1982):
Ammonoideos cretacicos del Prepirineo de la Provincia de Lleida . Publnes Geol. Univ, autonoma Barcelona Vol. 17 p. 197

Kennedy,J.W.. (1986):
The Campanian-Maastrichtian ammonite sequence in the environs of Maastricht (Limburg, the Netherlands) . Newsletters on Stratigraphy Vol. 16 p. 149-168

Kennedy,W.J.. (1986):
The ammonite fauna of the Calcaire à Baculites (Upper Maastrichtian) of the Cotentin Peninsula (Manche, France) . Palaeontology Vol. 29(1) p. 25-83

Kennedy,W.J.. (1987):
The ammonite faunas of the type Maastrichtian, with a revision of Ammonites colligatus Binkhorst, 1861 . Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Sciences de la Terre Vol. 56 p. 151-267

Ward,P.D.. and Kennedy,W.J.. (1993):
Maastrichtian Ammonites from the Biscay Region (France, Spain) . Memoir (The Paleontological Society), Journal of Paleontology34 (Supplement to Vol. 67)(5) p. 1-58

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