Bulimus fragilis Lamarck, 1822

Breure, Abraham S. H., 2016, Annotated type catalogue of the Orthalicoidea (Mollusca, Gastropoda, Stylommatophora) in the Muséum d’histoire naturelle, Geneva, Revue suisse de Zoologie 123 (1), pp. 57-103 : 69-70

Bulimus fragilis Lamarck, 1822

Figs 60-61

Bulimus fragilis Lamarck, 1822: 123 . – Delessert, 1841: pl. 28 figs 2a-b. – Chenu, 1850 [1842-1854]: pl. 9 figs 2a-b. – Mermod, 1951: 729, fig. 79.

Type locality: “l’Angleterre”, see remarks.

Label: No locality, but taxon label in Lamarck’s handwriting.

Dimensions: “Longueur, 1 pouce”; figured specimen herein H 28.3, D 13.1, W 6.5.

Type material: MHNG-INVE-51164 , five syntypes (Lamarck coll.).

Remarks: Lamarck described this species as British, having it received from Leach with the name Helix fragilis Montagu, 1803 (= Lymnaea stagnalis L., 1758). Pilsbry (1901 [ 1901 -1902]: 171) was the first to realize that this taxon could be a Drymaeus species ; he suggested “ Drymaeus stramineus , liliaceus, virginalis , or their allies”. Mermod (1951) confirmed the protoconch having the typical grating sculpture of Drymaeus . He compared the syntypes with specimens and figures in literature of the first two taxa mentioned by Pilsbry, and found them different from Lamarck’s specimens. He also compared the specimens with Pfeiffer’s description of Bulimus virginalis ( Pfeiffer, 1856: 46) , and suggested that these might be conspecific. However, comparing the specimens with the probable syntypes of Pfeiffer’s taxon ( Breure & Ablett, 2014: 207, fig. 24C), I disagree as Bulimus virginalis is more elongate and more slender than B. fragilis . Since the locality is unclear, it is preferred to keep this taxon as a distinct species until future research sheds more light on the systematic position.

Current systematic position: Bulimulidae , Drymaeus (Mesembrinus) fragilis ( Lamarck, 1822) .

Figures

Figs 42-65. Bulimulidae. (42) Bulimulus heloicus (d’Orbigny, 1835), syntype, MHNG-INVE-79903 (H = 22.4). (43) Bulimulus unicolor (Sowerby I, 1833), paralectotype of Bulimus petenensis Morelet, 1851, MHNG-INVE-60291 (H = 16.2). (44) Cochlorina aurismuris (Moricand, 1838), syntype, MHNG-INVE-60683 (H = 31.5). (45-46) Drymaeus (Drymaeus) abyssorum (d’Orbigny, 1835), respectively paralectotype of Helix abyssorum d’Orbigny, 1835, MHNG-INVE-63420 (H = 46.9), and paralectotype of Helix hygrohylaea d’Orbigny, 1835, MHNG-INVE-63469 (H = 43.9). (47-50) Drymaeus (Drymaeus) strigatus (Sowerby I, 1833), (47-48) syntype of Bulimus mariae J. Moricand, 1858, MHNG-INVE-64389 (H = 23.3), (49) syntype of Bulimus ceciliae J. Moricand, 1858, MHNG-INVE-63436 (H = 22.3), (50) syntype of Bulimus delphinae J. Moricand, 1858, MHNG-INVE-63443 (H = 22.4). (51) Drymaeus (Drymaeus) similaris (J. Moricand, 1856), syntype, MHNG-INVE-63531 (H = 23.6). (52) Drymaeus (Drymaeus) sachsei (Albers, 1854), syntype, MHNG- INVE-63524 (H = 31.9). (53) Drymaeus (Drymaeus) poecilus (d’Orbigny, 1835), paralectotype, MHNG-INVE-63506 (H = 26.8). (54) Drymaeus (Drymaeus) mexicanus (Lamarck, 1822), syntype, MHNG-INVE-51166 (H = 30.9). (55) Drymaeus (Drymaeus) draparnaudi (Pfeiffer, 1847), paralectotype of Helix torallyi d’Orbigny, 1835 [partim], MHNG- INVE-60326 (H = 24.9). (56-58) Drymaeus (Mesembrinus) virgulatus (Férussac, 1821), syntypes of Bulimus caribaeorum Lamarck, 1822, MHNG-INVE-51169 (H = 26.0).(59) Drymaeus (Mesembrinus) oreades (d’Orbigny,1835), paralectotype, MHNG-INVE-64483 (H = 31.4). (60-61) Drymaeus (Mesembrinus) fragilis (Lamarck, 1822), syntype (H = 28.3). (62) Drymaeus (Mesembrinus) immaculatus (C.B. Adams in Reeve, 1850), paralectotype, MHNG-INVE-64442 (H = 29.7). (63) Drymaeus (Mesembrinus) multilineatus (Say, 1825), paralectotype of Bulimus sisalensis Morelet, 1849, MHNG- INVE-64471 (H = 21.4). (64) Drymaeus (Mesembrinus) tropicalis (Morelet, 1849), paralectotype, MHNG-INVE-64519 (H = 24.3). (65) Drymaeus (Mesembrinus) leucomelas (Albers, 1854), paralectotype, MHNG-INVE-64455 (H = 25.9). ►