Taxonomy and paleoecology of Albian Madiela Formation gastropods, Gabonese coastal basin: N’Toum quarry section

Abstract

The taxonomy and paleoecology of the Albian gastropods from the N’Toum quarry geological section (N’Toum locality) are here discussed. Three genera including four species are identified: Ampullina sp., Tylostoma pallaryi (Peron & Fourtau), Lithomphalus sp. A and Lithomphalus sp. B. Three morphotypes are identified as Aporrhaidae gen. et sp. indet., Gast. gen. et sp. indet. 1 and Gast. gen. et sp. indet. 2. The genus Lithomphalus as the rest of gastropods assemblage are reported for the first time in the Gabonese coastal basin. The gastropod fauna from the N’Toum quarry section is marine. Its composition suggests soft to firm substrate. The depositional environment is considered as within the shallow photic zone with probably high amounts of organic debris in the substrate.

Albian bivalves from Madiela Formation in north Gabonese coastal basin

“…In the western part of the basin, the Madiela Formation consists of shales and carbonaceous shales (Teisserenc and Villemin, 1990;Chevalier et al, 2002). From a paleontological point of view, the Madiela Formation includes foraminifera, ostracods, gastropods, ammonites, calcareous nannofossils, bivalves and echinoids (Choubert, 1935;Hourcq, 1952;Dartevelle and Brébion, 1956;Dartevelle and Freneix, 1957;Hudeley and Belmonte, 1970;Grosdidier, 1979;Dupont, 1996;Chevalier et al, 2002;Musavu Moussavou and Mabicka Obame, 2015).…”

“…Among these, there is the Madiela Formation (Albian) which occurs in N'Toum region. The stratigraphical framework, together with the palaeontological value of the Madiela Formation have been discussed by several authors such as: Choubert (1935), Hourcq and Hausknecht (1954), Dartevelle and Brébion (1956), Dartevelle and Freneix (1957), Hudeley and Belmonte (1970), Teisserenc and Villemin (1990), Chevalier et al (2002), Musavu Moussavou and Mabicka Obame (2015). Systematic descriptions of the bivalve fauna from the Madiela Formation have been carried out only by Dartevelle and Freneix (1957).…”