| Measurements | D mm | H/D | T/D | O/D | H/T |
|---|---|---|---|---|---|
| CP-44 | 45 | 0.56 | 0.46 | 0.07 | 1.22 |
| CP-17 | 75.5 | 0.58 | 0.50 | 0.07 | 1.15 |
| Holotype | 106.7 | 0.61 | 0.49 | 0.04 | 1.25 |
| CP-323 | 111 | 0.59 | 0.50 | 0.05 | 1.19 |
| Age | Origin |
|---|---|
|
Lower Albian D. inaequinodum Malagasy zone |
Befamonto Boeny Region Madagascar |
Description. A very thick ammonite, terminated by a well-preserved septum, with a broad elliptical whorl section whose thickness is reached halfway along the flank. The umbilicus is tiny and funnel-shaped, without an umbilical rim. It is ornamented with 184 closely spaced and slightly flexuous ribs, tapering into faint striations on the inner half of the flanks. The nearly complete test, through transparency, unveils a few sutures with foliaceous saddles, ending in very well-developed, spatulate phyllites, at the base of which very few small internal phyllites are visible. The visible parts of the internal mold are smooth.
Remarques. According to Joly (1993), no Malagasy Phylloceras is as thick. Outside the island, the species exists in South Africa (Kennedy & Klinger, 1977). It is the most common Phylloceras in fossil sales, but often wrongly labeled P. velledae: the latter is more compressed (see its entry, with a comparative table between the two species) and its suture (right) is more deeply indented.