AMMONITES AND NAUTILOIDS OF WADI HAJAR 



97 



better developed in /4. loiicochense (Steuer. 1897: 61. pi. 2 figs 1-3), 

 the type species of Ande.sites. A. fasciculatiim (Steuer, 1897: 64. pi. 

 3, figs 1-3) is also very similar to A. malurguense, and it is probable 

 that A. loncochense and A. fasciculatiim are synonyms of A. 

 malargiiense . Another species from the same region. A. nocliiliferum 

 (Steuer. 1897: 64. pi. 1. figs 1-4), differs in having small lateral 

 tubercles from about 120 mm diameter. Both umbilical and lateral 

 tubercles are even larger in A. bitubercidatum Leanza (1945: 48: pi. 

 8, figs 1. 2) from the same area. 



Occurrence. Mintaq Member, Hajar Formation, Mintaq Salt 

 Dome; Occitanica Zone. Berriasian. 



Argentiniceras mintaqi sp. nov. 



Pi. 22, figs 1-4 



HOLOTYPE. CA694 from bed 57 in the Mintaq Member, Mintaq 

 Salt Dome. 



Paratypes. CA695 from bed 36 and CA696 from bed 57 in the 

 Mintaq Member, Mintaq Salt Dome. 



Other material. CA697 from bed 60 and CA698 from bed 64 in 

 the Mintaq Member, Mintaq Salt Dome. 



Diagnosis. Has approximately 1 1 primary and 22 secondary ribs 

 per whorl at 100-140 mm diameter, which is fewer than in other 

 species oi Argentiniceras; there are small, thin tubercles on the ribs 

 at the umbilical edge, and the secondary ribs pass across the venter 

 without interrupfion. 



Description. The holotype consists of a complete body-chamber 

 135° long and 140 mm diameter at its plain, slightly flared, mouth- 

 border. CA696 is a smaller immature specimen, with half a whorl of 

 body-chamber and a final diameter of 98 mm. CA695 is a fragment 

 of a body-chamber about 60° long and 105 mm diameter. CA697 

 and CA698 are smaller and less well-preserved, though they both 

 show the primary ribs of the inner whorls. The whorl section is 

 quadrate, with flat whorl sides and slightly arched venter. The 

 widely spaced primary ribs curve slightly backwards and divide into 

 secondaries about the middle of the whorl side, and then pass over 

 the venter without interruption. The ribs are raised near the umbilical 

 edge giving the appearance of slight tubercles, but on the inner 

 whorls of CA697 and CA698 the tubercles are larger. There are 1 1 

 primaries and 2 1 or 22 secondaries on the final half whorl of both the 

 holotype and CA696. 



Remarks. A. mintaqi is similar to A. malarguense (Steuer, 1897: 

 55, pi. 20, figs 1-3). but has fewer, more widely spaced ribs that bend 

 slightly backwards on the side of the whorl. It has the typical 

 characters of Argentiniceras - quadrate whorl section, bold, mainly 

 bifurcating ribs that are continuous across the venter, and small 

 umbilical tubercles. 



Occurrence. Mintaq Member, Hajar Formation, Mintaq Salt 

 Dome; Occitanica Zone, Berriasian. 



Genus TIRNOVELLA Nikolov, 1966 

 Type species. Berriasella alpillensis MazenoU 1939. 

 Remarks. Despite being placed in synonymy wnhSubthurmannia 



by Wright (1996: 55), it seems to be useful to keep Tinwvella 

 distinct on account of it much more involute, more compressed 

 whorls. In this respect it more closely TOicmMesSiihalpinites, which 

 differs in its stronger ribs and lateral tubercles on later whorls. In its 

 compressed whorls and umbilical tubercles Tirnovella is also like 

 Dalmasiceras. but the latter loses most of the ribs to become smooth 

 on its flatter whorl side at a much earlier stage than Tirnovella. 



Tirnovella occitanica (Pictet, 1867) 



PI. 22, fig. 5 



1867 Ammonites occitaniciis Pictet: 81. pi. 16. fig. 1. 



1939 Neocomites occitaniciis (Pictet); Mazenot: 213, pi. 33, figs 



1-3; pi. 34, figs 2, 3; pi. 35. fig. 1. 

 1951 Neocomites occitanicus (Pictet); Arnould-Saget: p. 81, pi. 



7, fig. 8. 

 1960 Neocomites occitanicus (Pictet); Nikolov: 182, pi. 21. figs 



1,2. 

 1962 Neocomites occitanicus (Pictet); Collignon: pi. 179. fig. 



797. 

 1968 Neocomites occitanicus (Pictet); Le Hegarat & Remane: 



22, pi. 4, fig. 1. 

 1973 Tirnovella occitanica (Pictet); Le Hegarat: 185. pi. 27. fig. 



9; pi. 49, fig. 5. 

 1982 Neocomites occitanicus (Pictet); Nikolov: 230, pi. 83, figs 



l,2;pl. 85, fig. 4. 



Material. Two specimens, CA 1296-97, from the Mintaq Mem- 

 ber, on the top of Jebel Madbi. 



Description. C A 1 296 consists of a body-chamber, ca. 1 20° long 

 between the last suture-line and the mouth-border at 70 mm diameter. 

 Although apparently complete and adult with somewhat modified 

 ribs on the final part of the body-chamber, there is no sign of a lappet 

 on the mouth-border. Its measurements are: at 68.0 mm diameter: 

 28.8 (0.43), 19.2 (0.29), 18.8 (0.28). The eariier whoris are pre- 

 served in the matrix as recrystallised calcite and are not exposed. 

 CA1297 is less well-preserved and has a maximum size of 98 mm 

 diameter. Both have involute, compressed whorls and a rounded 

 venter. Ribs are bundled in twos or threes to sharp, radially elongated 

 umbilical tubercles: they are gently flexuous on the side of the whorl 

 and pass across the venter with only a slight reduction of relief along 

 the mid- ventral line. On the final 50° of body-chamber of the smaller 

 specimen the ribs are reduced, though there is one 'periodic' heavier 

 rib and another at the mouth-border itself. The larger specimen has 

 coarser ribs, but they are only visible at larger diameters (70-98 mm) 

 than on the smaller specimen. 



Remarks. The better preserved Jebel Madbi ammonite is a good 

 match for the holotype and subsequently figured specimens from SE 

 France. Both ammonites were collected from an unrecorded level in 

 the Mintaq Member on the top of Jebel Madbi. That stratigraphical 

 level is well above the base of the Mintaq Member, and is probably 

 at a higher horizon than that of the main ammonite fauna in the 

 middle of the Mintaq Member in the Mintaq Salt Dom.e. The age 

 indicated is Occitanica Zone, and might well be high in that zone, if 

 it is younger than the Mintaq Salt Dome fauna. 



Occurrence. Mintaq Member, Hajar Formation, on the top of 

 Jebel Madbi; Occitanica Zone, Berriasian. 



PLATE 22 

 Figs 1-4 Argentiniceras mintaqi sp. nov.. Mintaq Member (fauna 13). Mintaq Salt Dome, la, lb. holotype, bed 57. CA694. body-chamber. xO.75. 2a, 



2b, bed 60. CA697. 3a, 3b, paratype, bed 57, CA696. 4a, 4b, paratype, bed 36, CA695, body-chamber. 

 Fig. 5 Tirnovella occitanica (Pictet). Mintaq Member (fauna 14), top of Jebel Madbi. 5a, 5b, CA1296. 



