Inosperma (Kühner) Matheny & Esteve-Rav., is monophyletic and four distinct clades have been recognized within the genus: two distinct Tropical Old World clades (1 and 2), the Maculata clade, and Inosperma sect. Inosperma. The specimens analysed in this study were collected between 1997 and 2022 in Benin (West Africa) in woodlands dominated by Isoberliniadoka Craib & Stapf, and/or I. tomentosa (Harms) Craib & Stap f, or gallery forest dominated by Uapacaguineensis Müll. Arg and/or Berlinia grandiflora (Vahl) Hutch. & Dalziel, in Okpara Forest (9.270131°N, 2.715440°E), N'dali Forest Reserve (9.758857°N, 2.696819°E), Koussoucoingou gallery forest (10.173066°N, 1.196233°E), Forest reserve of Gbadji (7.952167°N, 1.967867°E) and Forest reserve of Wari Maro (9.164733°N, 2.159917°E). The fresh basidiomata were dried using an electric dryer type Stöckli Dörrex for 24 hours at 60°C. Genomic DNA was extracted from dried specimens collected using the NuClean Plant Genomic DNA kit (ComWin Biotech, Beijing) and the ITS, LSU, RPB2 and TEF1 were amplified. The muscarine content was estimated in the UPLCMS/MS by using standard muscarine (Sigma-Aldrich, Chemical purity = 98%), and was calculated with an external standard method based on their respective calibration curves. The results show Inosperma macrocarpa as new to the science and the first record of I. afromelliolens from West Africa. The phylogenetic placement of I. macrocarpa was inferred, based on molecular evidence from the sequences of ITS, LSU, RPB2 and TEF1 and indicate that I.macrocarpa is nested an Old World Tropical clade 1. Complete description and illustrations, including photographs and line drawings, are presented for the new species. Morphological and molecular analysis based on collections from Benin also confirms the presence of I. afromelliolens in West Africa. A toxicity analysis shows that neither species contain muscarine which lend further support to the hypothesis that the ability to produce muscarine is a derived trait in Inosperma.