Gyrostomella P.Hesse 1911
Creators: name: Neiber, Marco T.
name: Korábek, Ondřej
name: Glaubrecht, Matthias
name: Hausdorf, Bernhard
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Stylommatophora
Helicidae
Gyrostomella

description: BIOGEOGRAPHY OF GYROSTOMELLA
The classification of Gyrostomella as a subgenus of Levantina from the Middle East by Hesse (1909a, b, 1911, 1918) suggested that Gyrostomella originated by a westward long-distance dispersal event of Levantina over almost 2000 km along the North African coast or that Gyrostomella is relictual of a formerly much wider range of Levantina (Fig. 2). More specifically, Neubert (1998) proposed that Gyrostomella and the Arabian Laevihelix (now considered a synonym of Levantina in the wide sense) are descendants of a southern branch of Levantina, which invaded Arabia and Northern Africa in the Miocene. With regard to the Arabian group, which is represented in our phylogeny by L. symensi Neubert, 1998, this scenario is compatible with our dated phylogeny (Fig. 4). However, our phylogenetic analyses strongly indicate that Gyrostomella is not related to the Eastern Mediterranean Levantina, but to the Maghrebian radiation of Helicinae, more specifically to Maurohelix from the Atlas Mountains (Figs 3, 4). Thus, the occurrence of Gyrostomella in the Nefusa Mountains in Libya could have originated from an eastward long-distance dispersal over about 800 km from the Atlas Mountains (Fig. 2). Alternatively, the disjunct distribution of Gyrostomella in Libya and Algeria could be a relict of a formerly wider range of the lineage, which became fragmented as a consequence of aridification processes and the spread of the Saharan desert during the late Miocene or early Pliocene (Zhang et al., 2014). Along with Eremina, which reaches the southern parts of Israel in the Middle East and dispersed also along the East African coast southwards to Cape Guardafui in Somalia and the western part of the Arabian Peninsula (Verdcourt, 1960; Neubert, 1998), it represents an eastern outpost of the Maghrebian radiation of Helicinae.
In Tripolitania, the Western and Eastern Mediterranean elements overlap, but Western Mediterranean land snail taxa dominate. Besides Gyrostomella, further Western Mediterranean land snail taxa represented in Tripolitania are Ferussacia carnea (Risso, 1826), Sphincterochila candidissima (Draparnaud, 1801), Xerosecta Monterosato, 1892 and Ganula Gittenberger, 1970, whereas Xerocrassa Monterosato, 1892, Xeromunda Monterosato, 1892 and Helix pronuba Westerlund & Blanc, 1879 are Eastern Mediterranean taxa (Sturany, 1909; Alzona, 1940; Neubert, 2014). In contrast, Eastern Mediterranean taxa predominate in the Cyrenaica region adjoining to the east.
description: Published as part of Neiber, Marco T., Korábek, Ondřej, Glaubrecht, Matthias & Hausdorf, Bernhard, 2022, A misinterpreted disjunction: the phylogenetic relationships of the North African land snail Gyrostomella (Gastropoda: Stylommatophora: Helicidae), pp. 1236-1251 in Zoological Journal of the Linnean Society 194 (4) on page 1245, DOI: 10.1093/zoolinnean/zlab059, http://zenodo.org/record/6459053