Hygromia (Riedelia) tassyi (Bourguignat, 1884)

Proćków, Małgorzata, Zając-Garlacz, Kamila S. & Bertrand, Alain, 2025, When morphology meets molecules: diversity of dart-bearing Hygromia Risso, 1826 land snails (Gastropoda: Hygromiidae), Zoological Journal of the Linnean Society 204 (1) : -

Hygromia (Riedelia) tassyi (Bourguignat, 1884)

( Fig. 10; Supporting Information, Fig. S9)

Helio tassyi Bourguignat, 1884: 357 . Type locality: ‘dans la vallée de Vicdessos, sur les rochers humides des contreforts du pic de Montcalm, au-dessus du village d’Auzat (Ariège)’. Syntype MHNG-MOLL-116290 ( Fig. 10A).

Hygromia gofasi Prieto & Puente, 1992 . Type locality: ‘ Santuario de Meritxell ( Andorra, CH8412, 1600m)’. Holotype ( Fig. 10D).

Diversity of dart-bearing Hygromia Risso, 1826 land snails • 27

Description

Shell width 9.4–12.1 mm, shell height 6.3–8.1 mm, whorls 5.1–6. Other measurements are presented in Table 1. Shell subdepressed to globose, very fragile. Whorls with moderate suture, slowly increasing. Last whorl rounded or slightly angulated; very occasionally with a fine whitish band at the periphery. Aperture slightly oblique with a whitish lip; reflected, completely covering or largely covering the umbilicus. Shell surface finely striated with curved ridges usually forming minute crescents, in places irregularly disposed ( Fig. 16). Love dart small, about 3 mm long, slightly twisted ( Fig. 21J). Shell and genitalia features are presented in Table 2.

Distribution

In this study, verified as endemics restricted to the type localities and adjacent areas in the Mediterranean Pyrenees, including five populations in the French department of Ariège and in Andorra (Supporting Information, Table S1; Fig. 1).

Habitat

Found in high mountain valleys above 900 m a.s.l. in humid and rocky habitats.

Hygromia (Riedelia) pyrenaica sp. nov.

( Fig. 9; Supporting Information, Fig. S11)

ZooBank registration urn:lsid:zoobank.org:act:1648CC42-3C12-40C4-9E2E-94FE6E7AF5A2

Type material: Holotype ( Fig. 9A): France, Occitanie , Ariège : Freychinède , Suc-et-Sentenac, 42°48′12′′N, 01°23′49′′E, 1535 m a.s.l., 01.05.2021, leg. A. Bertrand. Measurements: shell width 12.9 mm, shell height 9.2 mm, aperture width 7.9 mm, aperture height 5.1 mm, number of whorls 6. It is deposited in the Museum of Natural History, Wrocław, Poland, signature: MNHW-1532. Extraction voucher number: MNHW F.Fr _45 (DNA isolate Hygr59). GenBank number of sequence of cytochrome oxidase subunit I (COI): PQ067981, 16S ribosomal RNA (16S): PQ129257, ITS2 + 28S rRNA: PQ162550.

Paratypes: One adult specimen in alcohol (voucher number: MNHW F.Fr _46, DNA isolate: Hygr 59), in the collection of the Museum of Natural History , Wrocław . Additional material examined is detailed in Supporting Information, Table S1.

Etymology

Due to the occurrence in the Pyrenees.

Diagnosis

In terms of shell size and shape, as well as colour polymorphism, it most closely resembles H. tassyi . Te most characteristic features are poorly developed ridges, present between grow lines only on the upper surface of the shell ( Fig. 15E–H) and the fragile love dart, which is slightly curved, slender, and only a litle expanded at the base ( Fig. 21K).

Genetic differential diagnosis. Uncorrected p-distances between H. pyrenaica and other congeners are as follows (Supporting Information, Tables S3–S4):

(i) COI: 17.79% difference with H. cinctella , 14.04% with H. limbata s.s., 12.74% with H. l. hylonomia , 11.97% with H. sublimbata , 15.58% with H. tassyi , and 15.87% with Hygromia sp. -PAL.

(ii) 16S rRNA: 24.6% difference with H. cinctella , 12.48% with H. limbata s.s., 10.91% with H. l. hylonomia , 11.07% with Hygromia sp. -EP, 13.48% with H. tassyi , and 11.46% with Hygromia sp. -PAL.

Description

Shell width 11.6–13.3 mm, shell height 7.8–9.2 mm, whorls 5.5–6. Other measurements are presented in Table 1. Shell shape sub-globose. Convex spire with prominent apex. Whorls separated by distinct suture. Last whorl slightly angulated; light band always present. Aperture moderately oblique with whitish lip. Umbilicus covered by reflected columellar margin. Sculpture characterized by less distinct ridges, developed in between grow lines only on the upper side of the shell ( Fig. 15E–H). Love dart of medium length (3.5 mm), slender and fragile, slightly curved, only gently expanded at the base ( Fig. 21K). Shell and genitalia features are presented in Table 2.

Distribution

Live snails recorded from two sites in the French central Pyrenees, Ariège department (Freychinède and Col d’Agnes, Supporting Information, Table S1; Fig. 1).

Habitat

Beech forest in the karst landscape at c. 1500 m a.s.l. (Supporting Information, Fig. S12).