Abstract
The genus-group Hystricella R. T. Lowe, 1855 is revised on the basis of conchological, anatomical and genetic characteristics. A new genus Wollastonia gen. n., two recent species, W. jessicae sp. n. and W. klausgrohi sp. n., and one recent subspecies, W. jessicae monticola ssp. n. are described as new to science, as well as five fossil taxa, H. microcarinata sp. n., W. beckmanni sp. n., W. falknerorum sp. n., W. ripkeni sp. n., and W. inexpectata sp. n. For Helix vermetiformis R. T. Lowe, 1855, H. leacockiana Wollaston, 1878, H. oxytropis R. T. Lowe, 1831, H. duplicata R. T. Lowe, 1831 and H. oxytropis var. ß subcarinulata Wollaston, 1878 lectotypes are designated. For the taxa Helix bicarinata G. B. Sowerby I, 1824, Helix bicarinata var. ß aucta Wollaston, 1878 and Discula bulverii W. Wood, 1828 neotypes are selected. The taxa aucta and subcarinulata are elevated to specific rank. For the hitherto monospecific (sub-) genus Callina R. T. Lowe, 1855 it is shown that it is not closely related to the genus Discula but to the Hystricella-group and its generic rank is confirmed. The taxon D. bulverii W. Wood, 1828 is transferred from the genus Discula s. str. to the genus Callina. A further fossil taxon C. waldeni sp. n. is described as new to science.
Highlights
The island of Porto Santo (42.17 km2) is the northernmost island of the Madeiran Archipelago (Fig. 1), situated in the eastern Atlantic Ocean off the northwest African coast
There was nearly three times as much time on Porto Santo for the evolution of an endemic land snail fauna compared to the island of Madeira with an estimated age of 5.2 to 4.6 Ma before present (Geldmacher et al 2000; Ribeiro and Ramalho 2010) or to the Ilhas Desertas which are with approximately 3.6 Ma
We present a comprehensive revision of the species currently assigned to the genus Hystricella including, aside from conchological comparisons, anatomical descriptions of all recent taxa as well as molecular phylogenetic analyses on the basis of mitochondrial as well as nuclear DNA sequences
Summary
The island of Porto Santo (42.17 km2) is the northernmost island of the Madeiran Archipelago (Fig. 1), situated in the eastern Atlantic Ocean off the northwest African coast. The first more in-depth investigations of the terrestrial mollusc fauna of the Madeiran Archipelago were carried out by the clergyman Richard Thomas Lowe who visited the archipelago in 1828 for the first time The results of his colleting efforts in that year were published in 1831 in his important synopsis of the fauna “Primitiæ Faunæ et Floræ Maderæ et Portus Sancti”, in which many of the land snails from Porto Santo considered as valid taxa today were named and described. António da Costa de Paiva (Barão de Castelo de Paiva) described a number of species in 1866 and published a comprehensive thesis on the Madeiran land snail fauna in 1867, presenting an overview of the knowledge of the time Another important contribution towards an inventory of the malacofauna of the Madeira Archipelago was published by Thomas Vernon Wollaston under the title “Testacea Atlantica” in 1878, in which he summarised all the knowledge of the time on the non-marine molluscs of the Mid-Atlantic islands including the results of his five. Distribution data for all taxa are critically revised and stratigraphic as well as biogeographic relations are discussed
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