AMMONITES AND NAUTILOIDS OF WADI HAJAR 



Remarks. Elenoella differs from Berriasella s.s. in having um- 

 bilical tubercles and a tendency for the ribs to disappear, at least in 

 the macroconchs.The type species o^hoXhElenaella undDelphinella 

 conform to this definition, and although the species usually included 

 in Delphinella (eg. by Le Hegarat, 1971, and Nikolov, 1982) show 

 these characters more clearly. Elenaella has priority. 



Berriasella (Elenaella) sevenieri (Le Hegarat, 1973) 



PI. 20, figs 1,2 



1973 Delphinella sevenieri Le Hegarat: 1 10, pi. 42, figs 4, 7. 

 1973 Delphinella auzonensis Le Hegarat: 98, pi. 1 3, fig. 1 ; pi. 43, 

 figl. 



Material. CA674 from bed 36 and CA675 from bed 60 in the 

 Mintaq Member, Mintaq Salt Dome. 



Description. C A674 is a fragment of an outer whorl, half a whorl 

 long and about 95 mm diameter. The ribs are prominent at the 

 umbilical edge where they are pinched into small radially elongated 

 tubercles, of which there are 15 on the final half whorl; over most of 

 the side of the whorl the ribs are weak, especially in the middle of the 

 whorl side; near the bluntly angled ventro-lateral edge some ribs can 

 be seen to bifurcate, but they are not visible on the poorly preserved 

 venter. The inner whorls are not visible. CA675 is better preserved 

 with some of its shell replaced with dark red haematite, though 

 considerable areas of the shell surface are missing. It is 60 mm 

 diameter, moderately involute, and has flat whorl sides that converge 

 to a near-flat venter. Sharp primary ribs, which are already weaken- 

 ing on the middle of the whorl side at this size, bifurcate irregularly 

 then pass radially onto the venter which has a central smooth band. 

 There are small umbilical tubercles on each rib. 



Remarks. The holotypes ofZ). auzonensis andD. sevenieri do not 

 appear to differ in any respect, and the latter is used as the name for 

 the species because it is based on 12 specimens from known 

 horizons (plus 6 from unkown horizons), whereas the former name 

 is based on a unique holotype for which the horizon was originally 

 not recorded. CA674 is closely similar to that holotype of D. 

 auzonensis. In SE France specimens (including the holotype) have 

 been found in the Subalpina and Privasensis Subzones, Occitanica 

 Zone. 



Occurrence. Mintaq Member, Mintaq Salt Dome; Occitanica 

 Zone, Berriasian. 



Genus SUBSTEUEROCERAS Spath, 1923a 



Type species. Odontoceras koeneni Steuer, 1897. 



Remarks. Substeueroceras is not known to occur before the 

 middle of the Upper Tithonian, and ranges up into the Berriasian. 

 Verma & Westermann (1973: 228-234) reviewed the occurrences of 

 the genus in Europe and the Americas, and they included 

 Paradontoceras as a synonym. They referred many of the figured 

 specimens from Mexico and Argentina to the type species, S. 

 koeneni (Steuer), including S. lamellicostatum (Burckhardt, 1912: 

 167, pi. 40. figs 1-4, 6; ?also 1921, pi. 19, figs 9, 10, pi. 20, figs 4- 

 9), of which the lectotype (1912, pi. 40, figs 2-A. 6) is almost 

 idemical with Steuer's (1897, pi. 17, figs 1-3) lectotype. A few 

 species are more coarsely ribbed. Substeueroceras is similar to the 

 slightly older genus Kossmatia, from which it differs mainly in 

 having ribs that pass radially over the venter without the marked 

 forwards pointing inflection of Kossmatia. Any mid-ventral groove 

 or interruption of the ribs is confined to whorls up to about 50 mm 



91 



diameter (eg. Steuer, 1 897: pi. 17, figs 4, 5) in Substeueroceras, but 

 such a feature remains to much larger sizes in Kossmatia. 



Substeueroceras koeneni (Steuer, 1897) 



PI. 19, fig. 5 



1897 Odontoceras koeneni Steuer: 45, pi. 17 figs 1-5. 



1973 Substeueroceras koeneni (Steuer); Verma & Westermann: 



240, pi. 48, fig. 5; pi. 49, figs 1, 2 (see for a more complete 



synonymy). 

 1992 Substeueroceras koeneni {Steuer); Howarth: 638, pi. l.figs 



9, 10; pi. 2, figs 3, ?10. 



Material. 24 specimens: nine, CA940-48, from the shell bed 26 

 m above the base of the Arus Member in eastern Jebel Billum; two, 

 CA949-50, from the limestone 4 m above the base of the Mintaq 

 Member, and 12, CA951-62, from 9 m above the base of the same 

 member, in eastern Jebel Billum; one, CA685, from bed 60 in the 

 Mintaq Member in the Mintaq Salt Dome. 



DESCRIPTION. All the specimens are small fragments of parts of 

 whorls up to about 70 mm diameter. Some are crushed flat, but 

 others are uncrushed and show ribs passing radially across the venter 

 without interruption. The whorls have flattened sides and a nearly 

 flat venter, and the sharp primary ribs that bifurcate once or twice on 

 the sides of the whorl remain prominent up to the largest sizes seen. 



Remarks. These small fragments have ribs like those of the type 

 species of Substeueroceras, and do not become striate or smooth on 

 the sides of the whorl as in the new species S. striatum described 

 below. Similar fragments occur in the top of the Tithonian in 

 Kurdistan (Howarth, 1992: 638, pi. 1, fig 9, 10, pi. 2, figs 3, ?10; 

 though the venter of one of those specimens (fig. 10) has ribs 

 forming forwardly pointing chevrons and it might be a Kos.mwlia). 

 The extensive synonymy of the Argentinian and Mexican forms 

 given by Verma & Westermann (1973: 229-234, 240) is not repeated 

 here. They discussed the morphological features of these occur- 

 rences at length, and it is clear that the Yemeni fragments belong to 

 this fairly variable, moderately strongly ribbed, species of 

 Substeueroceras. 



Occurrence. Arus and Mintaq Members, Hajar Formation, east- 

 em Jebel Billum and the Mintaq Salt Dome; Durangites Zone, 

 Upper Tithonian, and Occitanica Zone, Berriasian. 



Substeueroceras striatum sp. nov. 



PI. 20, figs 3, 5, 6; PI. 21, fig. 1 



Holotype. CA963 from the limestone 4 m above the base of the 

 Mintaq Member, eastern Jebel Billum. 



Paratypes. 27 specimens, CA786-810 (CA786 is a slab with 

 three specimens), from a limestone 55 m above the base of the 

 Mintaq Member in the gorge at the southern end of Wadi Arus. 



Other material. Five specimens from eastern Jebel Billum: 

 four, CA964—67, from the same bed as the holotype, and CA968 

 from 7 m above the base of the Mintaq Member in the same section; 

 and CA684 from the top of bed 1,25m above the base of the Mintaq 

 Member in the Mintaq Salt Dome. 



Diagnosis. Differs from other species of Substeueroceras in re- 

 duction of the ribs to striae at 50-75 mm diameter, but the umbilical 

 edge ends of some ribs remain and occasional more widely spaced 

 stronger ribs occur. 



Description. The whorls are moderately involute and compressed, 

 with flat sides and rounded umbilical and ventro-lateral edges. The 



