Operculate land snails from three rainforest transects in northeastern Madagascar, with descriptions of nine new species and one new subspecies: (Gastropoda: Caenogastropoda)
Emberton, Kenneth C.
Three altitudinal transects in the region of Antalaha, northeastern Madagascar, resulted in 32 conchologically determined species in five genera of operculate land snails: the cyclophorids Acroptychia metablata (Crosse & Fischer 1873), Boucardicus cf. acutapex Emberton 2002, B. albocinctus (Smith 1893), B. ambatoensis n. sp., B. ampanefenae Emberton 2002, B. capestensis n. sp., B. deltastoma n. sp., B. josephinae Emberton 2002, B. lavalavus vilius n. subsp., B. lincolni n. sp., B. manomponae Emberton 2002, B. paulayi n. sp., B. reservei emberton 2002, B. sculptus Emberton 2002, B. slapcinskyi n. sp., B. soniae n. sp., B. thompsoni n. sp., Cyathopoma lava Emberton 2003, C. magnificum Emberton 2003, C. mahafinaratra Emberton 2003, and C. masoalae Emberton 2003; the pomatiasids Tropidophora bicarinata (Sowerby 1841), T. cf. ligatula (Grateloup 1840), T. lincolni n. sp., T. cf. perinetensis Fischer-Piette & Bedoucha 1965, T. pulchella (Sowerby 1843), T. soulaiana Fischer-Piette & Testud 1973, and T. unicarinata (Lamarck 1822); and the assimineids Omphalotropis bevohimenae Emberton 2004, O. tantelia Emberton 2004, O. sp. 1, and O. sp. 2.To aid in diagnosing species, a table is presented of shell variation within 14 highly variable species of Boucardicus, taking data from a recent monograph. Similar tables have been published previously for Cyathopoma, Tropidophora, and Omphalotropis.Despite intensive collecting during the rainy season(9 person-hours of micro-search, 6 person-hours of macro-search, and 48 sieved-and-picked liters of leaf litter and soil, per each of 15 localities), many of these species are represented by only one or a very few specimens. Thus no rainforest collection ever made for land mollusks in Madagascar can be considered saturated.Range extensions of 35-200 air km are reported for 11 small sized species, and intermediate populations are reported that reduce the maximum disjunctions between northern Boucardicus lavalava collections (reduced from 450 to 300 air km) and between Omphalotropis tantelia collections (reduced from 260 to 160 air km). These reports demonstrate how very poorly known are the true ranges (and conservation statuses) of Madagascar's small-sized operculate land snails.All of Madagascar's operculate genera are in great need of revision, using more than just shell data, but the above identifications are sufficient for planned analyses of species richness and abundance in the three altitudinal transects. Two subsequent papers will identify pulmonate land mollusks collected in the transects.