38 



1959 



?1984 



Taramelliceras holbeini (Oppel); Collignon: pi. 92, fig. 



419. 



Taramelliceras (Taramelliceras) trachinotum (Oppel); 



Verma & Westermann: 35, pi. 3, fig. 2. 



Material. Four specimens, CA1055-58, from limestones near 

 the top of the middle limestone part of the Kilya Member, Naifa 

 Formation, in Wadi Kilya. 



Description. The material consists of four large adult body- 

 chambers complete up to their final mouth-borders at diameters of 

 208, 145, 142 and 135 mm respectively. The preservation is rough, 

 and all are flattened to some extent. The whorls are highly invo- 

 lute, and have flat sides (probably accentuated by the lateral 

 crushing), an obtuse angle at the ventro-lateral edge, and an 

 arched, tabulate venter. No lateral ribs or striae can be seen on the 

 rough preservation (though the sides of the whorl appear to be 

 genuinely smooth), but prominent tubercles at the ventro-lateral 

 edge are elongated obliquely forwards; there are 15 such tubercles 

 per half whorl at 1 80 mm diameter on the largest specimen. The 

 position of the final adult septum is clear in three of the specimens 

 and the body-chamber is 0.61-0.67 whorls long. Few details of the 

 suture-lines can be seen. 



Remarks. These large, flat, nearly smooth body-chambers are 

 typical of T. compsum, which occurs in the Eudoxus and Beckeri 

 Zones in southern Germany (Holder, 1955: 140). They are easily 

 distinguished from similar-sized body-chambers of T trachinotum 

 (Oppel), which are much more coarsely ornamented throughout 

 growth and are usually somewhat older in the Divisum Zone and 

 possibly lower. A few similar specimens described by Spath (1928) 

 from Cutch, Collignon (1959) from Madagascar and Verma & 

 Westermann (1984) from Mombasa, are mosdy from the Beckeri 

 Zone. The rather similar large body-chambers ofT. (Metahaploceras) 

 pascoei (Spath, 1928: 147, pi. 8, fig. 3), from the Kimmeridgian of 

 Jurun, Cutch, differ in having rounded-elliptical rather than quadrate 

 whorls, and less prominent ventro-lateral tubercles. 



Occurrence. Middle part of the Kilya Member, Naifa Forma- 

 tion. Wadi Kilya; Beckeri Zone, Upper Kimmeridgian. 



Taramelliceras spp. indet. 



Material. Two fragments, CA972-73, from the ammonite bed 

 at the bottom of the middle limestone part of the Kilya Member, 

 Naifa Cliff; one is smooth, crushed and about 120 mm diameter, 

 and has a sharp venter due to crushing; the other has a whorl 

 height of 40 mm, feeble striate ribs and widely spaced ventro- 

 lateral tubercles. 



CA1059 is a fragment of part of a very large whorl from lime- 

 stones near the top of the middle limestone part of the Kilya Member 

 in Wadi Kilya. It has a whorl height of 85 mm, flat whorl sides, 

 flexuous ribs that are projected strongly on the venter, and only very 

 rudimentary ventro-lateral tubercles, and differs from the body- 

 chambers of 71 compsum that occur in the same bed in its ribbing and 

 lack of prominent tubercles. 



Two specimens, CA 1060-61, from the lower marly part of the 

 Kilya Member in Wadi Kilya, are poorly preserved and about 40 mm 

 diameter; one has moderate to fine flexuous ribs, the other has 

 prominent ventro-lateral tubercles, but the preservation is very 

 rough and neither is specifically determinable. 



Occurrence. Lower and middle parts of Kilya Member, Naifa 

 Formation; Beckeri Zone, Upper Kimmeridgian. 



M.K. HOWARTH 



Subgenus METAHAPLOCERAS Spath, 1925 



Type species. Metahaploceras affine Spath, 1925 {=Ammonites 

 strombecki Oppel, 1858). 



Taramelliceras (Metahaploceras) subsidens 



(Fontannes, 1879) PI. 1, fig. 5; PI. 3, fig. 6 



1879 Oppelia subsidens Fontannes: 50, pi. 7, fig. 7. 



1928 Taramelliceras aff. holbeini (Oppel); Spath: 138, pi. 14, fig. 



14. 

 1959 Taramelliceras subsidens (Fontannes); Berckhemer & 



Holder: 76. 



Material. Nine specimens, CA1062-70, from the upper marly 

 part of the Kilya Member in Wadi Kilya. 



Description. These four complete ammonites and five fragments 

 are all small, the largest being a slightly crushed imperfect specimen 

 75 mm diameter, while the others are uncrushed. The whorls are 

 involute and have a smoothly rounded elliptical whorl secfion, a fairly 

 sharp umbilical edge and vertical or undercut umbilical walls. The 

 ornament consists of weak or striate flexuous ribs that are prorsiradiate 

 on the inner half of the whorl, bent backwards at the middle of the side 

 of the whorl, where most of them bifurcate, then curve well forwards 

 on the outer half of the whorl. Small indisfinct ventro-lateral tubercles 

 occur on every 3rd or 4th rib, and there are very small mid-siphonal 

 tubercles on each rib. The ribs have become only slightly stronger on 

 the outer half of the whorl of the largest specimen at 74 mm diameter. 

 Parts of the suture-lines that are visible on several specimens are 

 complex, with much divided lobes and saddles. Up to half a whorl of 

 body-chamber is present on some specimens, but there are no adult 

 features and all are thought to be immature individuals. 



Measurements 











D 



Wh 



Wb 



U 



CA1062 



51.0 



26.2(0.51) 



15.6(0.31) 



8.9(0.17) 



CA1062 



34.4 



18.5(0.54) 



11.6(0.34) 



7.2(0.21) 



CA1063 



41.0 



21.0(0.51) 



13.4(0.33) 



7.1 (0.17) 



Remarks. These small specimens are not thought to be immature 

 individuals or microconchs of Taramelliceras (T) compsum, large 

 body-chambers of which occur in the Beckeri Zone in Wadi Kilya 

 and have stronger ribs and tubercles and more quadrate flat-sided 

 whorls at similar sizes (Holder, 1955: 1 10, figs 98, 104-108). In fact 

 the involute, smoothly rounded whorls, weak ornament and complex 

 suture-line are characters of the subgenus Metahaploceras. 

 Fontannes' original figure, although it is a drawing and only 43 mm 

 diameter, is a close match for the Yemeni specimens. A very similar 

 specimen from a poorly known horizon in the Kimmeridgian at 

 Cutch (Spath, 1928: 138, pi. 14, fig. 14) has rounded whorls, weak 

 ornament and complex suture-lines, and is sdll septate at its maxi- 

 mum diameter of 97 mm. 



Occurrence. Upper part of the Kilya Member, Naifa Formation, 

 Wadi Kilya; Hybonotum Zone, Lower Tithonian. 



Lamellaptychus 



PI. 1, fig. 6 



Material. 20 specimens: six, SM F 1 34 1 5- 1 8, F 1 3457-58, from 

 the bottom of the middle limestone part of the Kilya Member in 

 Naifa Cliff; 14, CA1071-84 (7 left and 7 right valves), from the 

 lower marly part of the Kilya Member in Wadi Kilya. 



Remarks. All are fragments of aptychi up to 40 mm long; they are 

 covered with coarse concentric folds on the outer surface and with 

 fine concentric striae on the inner surface (PI. 1, fig. 6). As typical 



