"The cone fauna of southernmost Madagascar is reviewed based on the material collected during the Atimo Vatae expedition. The expedition involved sampling from the intertidal to near shore by diving to ca 40 m, and offshore by dredging and trawling to 700 m. A total of 75 cone species was sampled. Strikingly, many tropical species are represented in the study area by single specimens whereas these are often quite common elsewhere in the tropical SW Indian Ocean, and it is hypothesized that these represent vagrants of occasionally settling larvae, rather than reproductive, self-recruiting populations. With these limitations, the resident cone fauna of Madagascar %22Deep South%22 probably consists of 58 species, of which 10 (17%) are regional endemics, thus confirming the existence of a distinct marine ecoregion, termed %22Toliaran Sub-Province%22 by Lorenz, which matches the distribution of seasonal upwelling fronts in South Madagascar. New taxonomic decisions in this regional monograph: Conasprella (Fusiconus) lernuriana sp. nov., Con us (Phasmoconus) galeyi sp. nov., Conus (Textilia) cymbioides sp. nov., Con us (Turriconus) aequiquadratus sp. nov. Conus biancae Bozzetti, 2010 and Cylinder priscai Bozzetti, 2012, are synonymized with Conus archiepiscopus Hwass in Bruguiere, 1792, and the latter is treated as a valid species from the Indian Ocean, molecularly distinct species from the Pacific Ocean Conus textile Linnaeus, 1758. Conus fuscatus Born, 1778, is treated as a valid, molecularly distinct species in the Conus imperialis complex. Darioconus fortdauphinensis Bozzetti, 2015 and D. miniturritus Bozzetti, 2017, are synonymized with Conus praelatus Hwass in Bruguiere, 1792; Darioconus pennaceus pseudoecho Bozzetti, 2013, is synonymized with C. vezoi Korn, Niederhofer & Blocher, 2000; Conus olgiatti Bozzetti, 2007, C. anosyensis Bozzetti, 2008, and Rolaniconus gilberti Bozzetti, 2012, with C. balteatus G.B. Sowerby I, 1833; Conus nimbosus nanoclarus Bozzetti, 2017, with C nimbosus Hwass in Bruguiere, 1792; Pionoconus atimovatae Bozzetti, 2012, with Conus simonis Bozzetti, 2010; Conus pennasilicorum Bozzetti, 2017, with C. alconnelli da Motta, 1986; Conus sazanka Shikama, 1970, with C. martensi E.A. Smith, 1884; Rolaniconus buniatus Bozzetti, 2013, with Conus varius Linnaeus, 1758; and Conus multibandatus Bozzetti, 2017, with C. coronatus Gmelin, 1791." . "Monnier et al. (2018)" . "2018"^^ . "2018"^^ . . "Monnier et al. (2018)" . . "The cone fauna of southernmost Madagascar is reviewed based on the material collected during the Atimo Vatae expedition. The expedition involved sampling from the intertidal to near shore by diving to ca 40 m, and offshore by dredging and trawling to 700 m. A total of 75 cone species was sampled. Strikingly, many tropical species are represented in the study area by single specimens whereas these are often quite common elsewhere in the tropical SW Indian Ocean, and it is hypothesized that these represent vagrants of occasionally settling larvae, rather than reproductive, self-recruiting populations. With these limitations, the resident cone fauna of Madagascar %22Deep South%22 probably consists of 58 species, of which 10 (17%) are regional endemics, thus confirming the existence of a distinct marine ecoregion, termed %22Toliaran Sub-Province%22 by Lorenz, which matches the distribution of seasonal upwelling fronts in South Madagascar. New taxonomic decisions in this regional monograph: Conasprella (Fusiconus) lernuriana sp. nov., Con us (Phasmoconus) galeyi sp. nov., Conus (Textilia) cymbioides sp. nov., Con us (Turriconus) aequiquadratus sp. nov. Conus biancae Bozzetti, 2010 and Cylinder priscai Bozzetti, 2012, are synonymized with Conus archiepiscopus Hwass in Bruguiere, 1792, and the latter is treated as a valid species from the Indian Ocean, molecularly distinct species from the Pacific Ocean Conus textile Linnaeus, 1758. Conus fuscatus Born, 1778, is treated as a valid, molecularly distinct species in the Conus imperialis complex. Darioconus fortdauphinensis Bozzetti, 2015 and D. miniturritus Bozzetti, 2017, are synonymized with Conus praelatus Hwass in Bruguiere, 1792; Darioconus pennaceus pseudoecho Bozzetti, 2013, is synonymized with C. vezoi Korn, Niederhofer & Blocher, 2000; Conus olgiatti Bozzetti, 2007, C. anosyensis Bozzetti, 2008, and Rolaniconus gilberti Bozzetti, 2012, with C. balteatus G.B. Sowerby I, 1833; Conus nimbosus nanoclarus Bozzetti, 2017, with C nimbosus Hwass in Bruguiere, 1792; Pionoconus atimovatae Bozzetti, 2012, with Conus simonis Bozzetti, 2010; Conus pennasilicorum Bozzetti, 2017, with C. alconnelli da Motta, 1986; Conus sazanka Shikama, 1970, with C. martensi E.A. Smith, 1884; Rolaniconus buniatus Bozzetti, 2013, with Conus varius Linnaeus, 1758; and Conus multibandatus Bozzetti, 2017, with C. coronatus Gmelin, 1791." . . "Monnier, E., Tenorio, M., Bouchet, P. & Puillandre, N. 2018. The cones (Gastropoda) from Madagascar 'Deep South': composition, endemism and new taxa. Xenophora, 19: 25-75." .