Ceratides

[drbush]

HI

I went to my favorite fossil hunting  area (Sulaiy formation\Berriasian \ cretaceous of Saudi Arabia) and found this fossils  . I hope you help me in identifying this fossil is it Ceratides sp 

or other types .

It is large 15 cm wide and 10 cm high

[Ludwigia]

"Ceratides" is not a proper scientific term. If you mean Ceratite, then this is not one, since they stopped existing long before the cretaceous and had developed by then into ammonites. Although the sutures are reminiscent of those from a ceratite, your sample can only be part of the outer whorls of an ammonite.

[abyssunder]

I don't know if there were ammonoids described from the Sulaiy formation, but were mentioned unidentified ammonites showing affinities with Knemiceras and Hypengonoceras in the overlying Yamama formation. They might be close to your specimen.

 

" The name Ceratites was introduced by de Haan (1825) for a group of Triassic ammonites with simplified suture lines. As early research developed, Ceratites-like fossils of Cretaceous age were discovered, so early palaeontologists included these fossils into the ceratitid group, naming them as Cretaceous Ceratites (Buch, 1848, p. 30) or "pseudo-ceratites based on an apparent resemblance between the sutures of Triassic ceratitids and those of Cretaceous engonoceratids" (Hyatt, 1903; G. Scott, 1940a, 1940b; Kennedy & Cobban, 1976; Rawson, 1981; Kennedy et al., 1998a). The first engonoceratid ammonite was published by d'Orbigny (1841) as Ammonites Vibrayeanus [= Neolobites vibrayeanus] from France, and by Buch (1848) as Ammonites Syriacus [= Knemiceras syriacum] from Lebanon, and Ammonites pierdenalis [= Engonoceras pierdenalis] from Texas. Buch (1848) also called attention to the importance of the group referring to them as Cretaceous ceratitids ('Kreide-Ceratit'). Although Buch (1848) reported other "ceratitids" (whose suture lines superficially resemble those of the Triassic Ceratites) such as Ammonites Ewaldi and Ammonites Robini [= Metatissotia ewaldi and M. robini], these species belong to discrete taxa (Acanthoceratoidea) with no direct phyletic connection to the engonoceratids. The family name Engonoceratidae was introduced by Hyatt (1900, p. 585) to include Protengonoceras, Engonoceras, Metengonoceras, and Neolobites. Later Hyatt (1903, p. 144) established the family Knemiceratidae for Knemiceras. Based on the suture line Douvillé (1912, 1928, 1931) placed the group in the Pulchelliidae, an assignment accepted by G. Scott (1940b, p. 1066). Spath (1922, 1924) introduced Hypengonoceras, and Parengonoceras. The last described member of the family is Platiknemiceras (Bataller, 1954). " - Bujtor L. 2010. Systematics, phylogeny and homeomorphy of the Engonoceratidae HYATT, 1900 (Ammonoidea, Cretaceous) and revision of Engonoceras duboisi LATIL, 1989.- Carnets de Géologie / Notebooks on Geology, Brest, Article 2010/08 (CG2010_A08)

[BobWill]

With that much wear the sutures may be worn away so what we see are the septa walls instead. They would show less folding as they near the center so not very diagnostic.