Pseudothurmannia (Parathurmannia) sarasini: In

Hoedemaeker, Philip, 2013, Genus Pseudothurmannia Spath, 1923 and related subgenera Crioceratites (Balearites) Sarkar, 1954 and C. (Binelliceras) Sarkar, 1977 (Lower Cretaceous Ammonoidea), Revue de Paléobiologie 32 (1), pp. 1-209 : 23

Pseudothurmannia (Parathurmannia) sarasini: In this

species, umbilical bullae appear much earlier than in P.

(K.) caravacaensis, which means that the ontogenetic

stage with the balearis -like ornamentation has

disappeared, possibly through persistent acceleration. P.

(Pa.) sarasini has four ornamental ontogenetic stages:

1. The first stage consists of 4-5, rarely six, flexuous intermediate ribs to one main rib.

2. The second stage begins at a diameter of 40 mm and consists of rather coarse, less flexuous ribbing with two intermediate ribs to one main rib. In this stage small lateral tubercles on the main ribs appear; they disappear with the beginning of the third ornamental stage, at a diameter of 68 mm.

3. The third stage has strong, widely separated main ribs, every two of which are separated by 3-4 intermediate ribs.

4. The fourth stage begins at a diameter of 83 mm, is situated on the living chamber, and is considered the adult stage. In this stage the intermediate ribs become more or less effaced below midflank as in P. (K.) caravacaensis .

The umbilical width becomes equal to the whorl height

at a diameter of 100 mm. The largest specimen hitherto

found is 107 mm in diameter.