Sunday, 26 July 2020


Lovely defined sutures on this rather involute, high-whorled ammonite from the middle part of the Lower Albian in the Mahajanga Province, northwestern Madagascar. This specimen of Phylloceras velledae (Michelin) has a shell with a small umbilicus, arched, acute venter, and at some growth stage, falcoid ribs that spring in pairs from umbilical tubercles, disappearing on the outer whorls.

While the large island of Madagascar off the southeast coast of Africa is known more for exotic lemurs, rainforests & beaches, it also boasts some of the world's loveliest fossils.

This specimen is from a quarry near the top of an escarpment, 3 km to the west of the village of Ambatolafia (coordinates: Lat. 16.330 23.600 S, Long. 46.120 10.20 E). Judging from plate tectonic reconstruction (Stampfli & Borel, 2002), the area was located in middle latitudes within the tropical-subtropical climatic zone at palaeo-latitudes of 40E45.S in the late Early Cretaceous of the early Albian approximately 113.0 ± 1.0 Ma to 100.5 ± 0.9 Ma. 

Madagascar was carved off from the African-South American landmass early on. The prehistoric break-up of the supercontinent Gondwana separated the Madagascar–Antarctica–India landmass from the Africa–South America landmass around 135 million years ago. Madagascar later split from India about 88 million years ago, during the Late Cretaceous, so the native plants and animals on the island evolved in relative isolation. It is a green and lush island country with more than it's fair share of excellent fossil exposures. 

Along the length of the eastern coast runs a narrow and steep escarpment containing much of the island's remaining tropical lowland forest. If you could look beneath this lush canopy, you'd see rocks of Precambrian age stretching from the east coast all the way to the centre of the island. The western edge is made up of sedimentary rock from the Carboniferous to the Quaternary. The beauty you see here is from sedimentary exposures from northwestern Madagascar and is in my personal collection. There is an exceptionally well-preserved and unusually large specimen in the collections of João Da Costa that I'll photograph and include in a future post.