68 
an earlier acanthoceratine genus, probably Cunningtoniceras 
Collignon, 1937 as detailed below. 
Nigericeras scotti Cobban (1971: 18, pl. 9, figs 1-4; pl. 18, figs 
1-9; text-figs 15-19) from the terminal Cenomanian of the 
United States western interior may be a Pseudovascoceras. It 
lacks the suture pattern typical of Nigericeras but resembles the 
more strongly ornamented examples of P. nigeriense. 
The unnamed specimen from Turkestan figured by Kler 
(1909: pl. 8, figs 3a, b; text-fig. 6) may also be a Pseudovascoceras. 
The English specimen (C.82287) from the high Cenomanian 
referred to Nigericeras cf. gignouxi Schneegans by Wright & 
Kennedy (1981: 85, pl. 15, figs 6a, b) is a fragment, the ornament 
and suture pattern of which cannot be made out clearly. It might 
be best referred to Pseudovascoceras. It occurs alongside 
Thomasites gongilensis. In Nigeria Thomasites occurs well above 
the stratigraphical level of Nigericeras, but its earliest members 
are coeval with P. nigeriense. 
Pseudovascoceras nigeriense (Woods, 1911) 
Figs 14-24, 36, 37 
21909 ~~ Vascoceras cauvini Chudeau: pl. 3, figs 4a, b (only). 
1911  Vascoceras nigeriense Woods: 281, pl. 21, fig. 6; pl. 22, 
figs 2, 3. 
21943 + Vascoceras nigeriense Woods; Schneegans: 133, pl. 4, 
fig. 1. 
21943 Paravascoceras cf. barcoicense (Choffat) Schneegans: 
134, pl. 8, fig. 1. 
1954b Vascoceras nigeriense Woods; Reyment: 256. 
21955  Nigericeras ogojaense Reyment: 62, pl. 13, fig. 6; pl. 14, 
fig. 3; text-fig. 28. 
1957 —_ Vascoceras nigeriense Woods; Barber: 15, pl. 4, fig. 2; 
pl. 26, figs 1, 2. 
1957 = Nigericeras costatum Barber: 29, pl. 10, figs 3, 4; pl. 11, 
fig. 3; pl. 30, figs 1-7. 
1957 = Nigericeras glabrum Barber: 29, pl. 10, figs 1, 2; pl. 30, 
fig. 8. 
1957 Nigericeras? intermedium Barber: 31, pl. 11, figs 1, 2; 
pl. 30, figs 9, 10. 
1957 =Paramammites tuberculatus Barber: 31, pl. 12, fig. 1; pl. 
13, fig. 2; pl. 31, figs 1-3, 9. 
1957 Paramammites raricostatus Barber: 33, pl. 12, fig. 3; pl. 
31, figs 4, 6, 7. 
1957 Paramammites inflatus Barber: 33, pl. 12, fig. 2; pl. 13, 
fig. 1; pl. 31, figs 5, 8. 
Paramammites laffitei Collignon: 186, pl. A, fig. 2. 
Paramammites subtuberculatus Collignon: 187, pl. A, 
fig. 3. 
1965 + Vascoceras nigeriense Woods; Reyment: pl. 2, fig. 2. 
1965 Nigericeras costatum Barber; Reyment: pl. 3, fig. 13. 
21965 
21965 
21965 — Nigericeras ogojaense Reyment; Reyment: pl. 3, fig. 14. 
1965 Paramammites tuberculatus Barber; Reyment: pl. 3, 
figs 15a, b. 
1980  Nigericeras costatum Barber; Wright & Kennedy: figs 
10a, b. 
1989  Paravascoceras nigeriense? (Woods); Meister: 14, pl. 5, 
fig. 1; pl. 6, fig. 1; text-fig. 11. 
1989 - Vascoceras costatum (Barber) Meister: 23, pl. 10, figs 3, 
5; pl. 11, figs 1, 2, 5; text-figs 16a—d. 
1989  Vascoceras costatum glabrum (Barber) Meister: 23, pl. 
9, figs 2, 4; pl. 10, fig. 4; text-figs 16e—g. 
1989 _Vascoceras ellipticum Barber; Meister: 28, pl. 12, figs 1, 
3; text-fig. 18. 
1989 Paramammites subconciliatus (Choffat) Meister: 30, pl. 
P.M.P. ZABORSKI 
12, figs 4, 5; pl. 13, figs 1-4; pl. 14, figs 1, 2; pl. 15, figs 1, 
4; text-fig. 21. 
1989 Paramammites polymorphus (Pervinquiére); Meister: 
36, pl. 14, figs 3, 4; text-fig. 24. 
1990a_ Vascoceras nigeriense Woods; Zaborski: fig. 25. 
1992  Vascoceras sp. gr. costatum (Barber) sensu Meister, | 
1989; Courville: pl. 5, fig. 3; pl. 6, figs 2, 3. 
LECTOTYPE. Specimen B3237, Sedgwick Museum, Cambridge | 
(see Woods 1911: pl. 22, figs 2, 3); from Kunini, north-eastern 
Nigeria (selected by Berthou, Chancellor & Lauverjat 1985: 69). | 
PRESENT MATERIAL AND OCCURRENCE. Sixty-one specimens, | 
C.93305-8, C.93311, C€.93315-21, C.93370-93, C.93494a-d, 
C.93495a-f, C.93496a—d, C.93497-507, Pindiga Formation, unit 
O, Ashaka. | 
DIMENSIONS. See Fig. 12. 
REMARKS. P. nigeriense is generally a moderately evolute | 
species having rather compressed to moderately depressed 
whorls with a rounded to subpentagonal outline. In overall shell 
proportions it overlaps with both Vascoceras bullatum and V. | 
globosum costatum; smooth individuals are often especially | 
difficult to distinguish from the last form. The adult diameter 
varies from about 85 to 120 mm when the body-chamber makes 
up two-thirds of the final whorl. | 
It is in its ornamentation that P nigeriense shows its greatest 
variation, from almost entirely smooth to highly decorated end 
members. A variation series is shown in Figs 14—24, and there is | 
also abundant figured material in the previous literature (see 
synonymy list). Dissection of numerous individuals, including 
those with smooth outer whorls, shows that siphonal tubercles 
are consistently developed but they may have already 
disappeared by a diameter of 10 mm. Outer ventrolateral | 
tubercles are also commonly developed while inner ventrolateral _ 
and umbilical tubercles may or may not be present. One | 
combination or another of tubercle rows may persist throughout 
the length of the septate whorls or disappear at any stage in | 
ontogeny. Umbilical tubercles, when present, are the most’ 
persistent ornamental features and siphonal tubercles are the | 
least, with the result that numerous individuals show six rows of | 
tubercles in their middle growth stages. Strongly tuberculated | 
forms may in addition display rectiradiate to concave ribs | 
connecting the tubercles. The ribs may branch across the venter| 
while additional ribs with inner and/or outer ventrolateral and! 
siphonal tubercles may be intercalated. Ornamental strength is! 
initiated very early in ontogeny. The ornament of the’ 
phragmocone may persist onto the adult body-chamber or this) 
part of the shell may be smooth. Most frequently, however, there 
are irregularly developed ribs upon the flanks and the venter! 
which vary from strong, broad fold-like structures to fine, dense 
crease-like features recalling those in adult Vascoceras woodsi 
and V. bullatum. 
Suture patterns are of a simplified type but the saddles tend to) 
be elongated, especially in strongly ornamented forms. The 
lateral lobe is fairly wide and often subdivided by a distinct 
median element. 
Meister (1989) separated members of P nigeriense from 
Ashaka into six taxa, Paravascoceras nigeriense (Woods). 
Vascoceras. ellipticum Barber, Paramammites aff. gr 
polymorphus (Pervinquiére), P  subconciliatus (Choffat). 
Vascoceras costatum (Barber) and V. costatum glabrum (Barber) 
Nevertheless, he showed how the ornamental variation betweer! 
the last three could easily be interpreted in terms ol| 
