AMMONITES AND NAUTILOIDS OF WADI HAJAR 



67 



1971 Aspidoceras longispinum (J. de C. Sowerby); Callomon & 



Cope: 174, pi. 12. figs 1-3. 

 1979 Aspidoceras longispinum (J. de C. Sowerby); Schairer & 



Barthel: 18, pi. 3, figs 3-8; pi. 4. 

 1984 Aspidoceras aff. acanthicum (Oppel); Verma & 



Westermann: 65, pi. 15, fig. 1. 

 1984 Aspidoceras iphiceroides (Waagen); Verma &Westermann: 



66, pi. 15, figs 2, 3; pi. 16, figs 1-3. 



1984 Aspidoceras cf. iphicerum (Oppel); Verma & Westermann: 

 68, pi. 16, figs 4, 5. 



1985 Aspidoceras longispinum (J. de C. Sowerby); Checa: 76, pi. 

 9, figs 1-3; pi. 10, fig. 2; pi. 14, fig. 2: pi. 15, fig. 1. 



Material. 12 specimens from the Kilya Member: CA 1184-86 

 from the upper marly part, CAl 187-89 from the middle limestone 

 part and CA 1 1 90 from the top of the lower marly part, all in Wadi 

 Kilya; CA1037 and CA1038 from a shell bed at the top of the middle 

 limestone part, and CAl 035, CAl 036 and SM F. 12201 from the 

 base of the same part of the Kilya Member in Naifa Cliff. 



Description. The largest specimen is poorly preserved and partly 

 crushed, but is 300 mm diameter at its (?adu]t) mouth-border, has a 

 little more than half a whorl of body-chamber, and a final septum at 

 about 210 mm diameter; apart from remnants of large umbilical 

 tubercles its ornament is not preserved. Three specimens are poorly 

 preserved fragments of smaller body-chambers. Three others are 

 crushed phragmocones, all strongly tuberculate, one of which ends 

 at 1 20 mm diameter and is followed by one-third of a whorl of body- 

 chamber. The remaining five specimens are well-preserved 

 phragmocones up to 1 20 mm diameter. 



The whorls are evolute with a rounded depressed whorl section. 

 The ornament consists of two rows of small to medium sized 

 tubercles, one at the umbilical edge, the other at, or just ventral of, 

 the middle of the whorl side. In both rows the number of tubercles 

 varies from 9-18 per whorl at 75 mm diameter. Ribs are mostly 

 absent, but low undulations occur between the rows of tubercles and 

 there are striae on the shell surface. 



Measurements 

 D 

 CAl 185 108.0 

 CAl 186 75.0 



SMF. 12201 54.3 



Wh 



41.2(0.38) 

 32.5 (0.43) 

 22.0(0.41) 



Wb 

 56.5 (0.52) 

 37.3 (0.50) 

 26.8 (0.49) 



21.2(0.28) 

 18.9(0.35) 



Remarks. A bituberculate species of Aspidoceras is widely dis- 

 tributed in Kenya, Somalia, Ethiopia, Yemen and Cutch. In Kenya, 

 Yemen and Cutch it undoubtedly occurs in the Beckeri and 

 Hybonotum Zones. Some of the Yemen specimens (eg. PI. 9, fig. 2) 

 are morphologically idendcal with the holotype of A. longispinum 

 and with Damon's specimen, both refigured by Callomon & Cope 

 (1971), and of Eudoxus Zone age in southern England. The 12 

 Yemen and about 35 other figured specimens from east Africa and 

 Cutch of this consistently bituberculate, massive-whorled, depressed 

 species show a moderate amount of variation in whorl proportions 

 and development of tubercles. Much of the variation in tubercle size 



and development is due to the differing preservation, because tuber- 

 cles are always prominent where the shell is preserved, but they are 

 much reduced or almost absent on inner moulds, especially when 

 such moulds are abraded. 



A. rogoznicense is a very similar, but slightly younger species, 

 which differs in having more depressed whorls, and the two rows of 

 tubercles are slightly closer together (compared with the whorl 

 height) according to the analysis of Checa (1985: 98). 



Occurrence. Lower, middle and upper parts of the Kilya Mem- 

 ber, Naifa Formation, Naifa Cliff and Wadi Kilya; Beckeri Zone, 

 Upper Kimmeridgian, and Hybonotum Zone. Lower Tithonian. 



Aspidoceras apenninicum Zittel, 1870 



PI. 9, fig. 3; pi. 12, fig. 4 



1869 Aspidoceras apenninicum TXtitV. 149. 



1 870 Aspidoceras apenninicum Zittel; Zittel: 78, pi. 5 (29), fig. 6. 

 1901 Aspidoceras apenninicum Zittel; Canavari: 12 (84), pi. 3 



(22), figs 1,2. 

 1943 Aspidoceras evolutum Scott: 78, pi. 17. figs 1. 4. 

 1959 Epaspidoceras rupellense (d'Orbigny); Collignon: pi. 132, 



fig. 493. 



1984 Aspidoceras cf. apenninicum Zittel; Verma & Westermann: 

 69, pi. 17, fig. 1. 



1985 Aspidoceras apenninicum Zittel; Checa: 84, pi. 13, figs 1- 

 3; pi. 14, fig. 1. 



Material. Nine specimens, CAl 191-99, from the upper part of 

 the middle limestone part of the Kilya Member in Wadi Kilya. 



Description. The collection consists of nine solid, uncrushed, 

 roughly preserved body-chambers, the largest being part of a speci- 

 men of about 230 mm diameter. Final septa are preserved at the 

 smaller end of seven specimens, at diameters in the range 103-180 

 mm. and poorly preserved crushed inner whorls are present in two 

 specimens. The largest specimen has whorl height and breadth of 

 68.5 and 63 mm respectively at 230 mm diameter. The whorls are 

 evolute and the whorl section is quadrate and only slightly higher 

 than broad. The umbilical walls are rounded and merge smoothly 

 into the whorl sides, which converge slowly towards the arched 

 venter. At the largest sizes the venter becomes slightly angled. The 

 ornament consists of prominent umbilical and ventro-lateral tuber- 

 cles, and the latter tend to become clavate at large sizes. Rounded 

 ribs of low relief connect the tubercles and are mostly single, but 

 occasionally two ribs issue from an umbilical tubercle, so that there 

 are a few more ventro-lateral than umbilical tubercles. Ribs remain 

 of low relief and are angled forwards on the venter, but they tend to 

 become raised in mid-venter, which becomes increasingly angled 

 with growth. 



Measurements 









D 



Wh 



Wb 



U 



CAl 1922 153 



48.5 (0.32) 



46.5 (0.30) 



66.5(0.43) 



CAl 1965 230 



68.5 (0.30) 



63.0 (0.27) 



— 



CAl 1998 188 



62.0(0.33) 



57.0 (0.30) 



— 



PLATE 11 



Fig. 1 Idoceras ahwarense sp. nov, holotype. Ghanam al Kuffar (13°45'N, 46°4rE). in Wadi Ahwar, 30 km north of Ahwar and 36 km north of the mouth 



ofWadi Ahwar on the coast of the Gulf of Aden, la, lb, C.71097, wholly septate. 

 Fig. 2 Orthaspidoceras avellanum Zittel, upper marly part of Kilya Member (fauna 8), Wadi Kilya. 2a, 2b, CA1205. 

 Fig. 3 Simaspidoceras argobbae (Dacque), Breadloaf Concretions, Kilya Member (fauna 7), east cliff, Wadi Arus. 3a, 3b, CA741 . 

 Fig. 4 Erymnoceras (Pachyermnoceras) jarryi (Douville), 17 m below top of the Upper Shuqra, Shuqra Formation (fauna 1), central Jebel Billum. 4a-4c, 



CA838. 

 Fig. 5 Aspidoceras longispinum (J. de C. Sowerby), upper marly part of Kilya Member (fauna 8). Wadi Kilya. 5a, 5b. CAl 186, wholly septate. 



