THE GENUS CANARIELLA HESSE, 1918, AND ITS POSITION IN THE FAMILY HYGROMIIDAE (GASTROPODA, PULMONATA, HELICOIDEA)

Canariella is a poorly known genus of the Hygromiidae, endemic to the Canary Islands, with 18 nominal taxa of specific and subspecific rank. Until now, no information on the internal anatomy of its genital duct s was known, and the external morphology of the genital system, which lacks any trace of the dart-sac complex, was known for only five speci es. In another article (Groh et al., in press), four nominal taxa (= t hree species) of Canariella were described conchologically and anatomi cally. The present work treats the remaining known species. (We exclud e Helix plutonia Lowe, 1861, which has been included in Canariella but really belongs in a new genus of the Hygromiidae.) Lectotypes are des ignated for the type species, Carocolla hispidula Lamarck, 1822; Helix bertheloti Ferussac, 1835; H. everia Mabille, 1882; H., fortunata Shu ttleworth, 1852; H. (Gonostoma) hispidula subhispidula Mousson, 1872; and H. (Ciliella) lanosa Mousson, 1872. The holotypes of Helicodonta s alteri Gude, 1911, and Helix (Gonostoma) beata Wollaston, 1878, are al so studied. These eight taxa differ slightly from one another in shell morphology, but agree in the morphology of the genital system, and th ere is no geographical isolation among them (Fig. 39); therefore, they are considered to belong to a single species, and the last seven name s are synonymized with Carocolla hispidula. However, six populations a re conchologically distinguishable, a sign of the beginning of radiati on, and therefore we consider them with the rank of infrasubspecific v arieties. Lectotypes of Helix (Gonostoma) gomerae Wollaston, 1878; Car ocolla planaria Lamarck, 1822; Helix afficta Ferussac, 1832; and H. eu tropis Shuttleworth, 1860, are also designated. Applying the results o f this study and the authors' knowledge of further new species not yet described, the following new diagnosis of Canariella is proposed: Man tle collar with four small lobes (subpneumostomal, left dorsal, right dorsal and right lateral; as an exception, C. eutropis has also the le ft lateral lobe). Kidney sigmurethric, without secondary ureter. Centr al and first lateral radular teeth with small but evident ectocones. R ight ommatophore retractor passing between penis and vagina. Genital s ystem without the dart-sac complex and with several vaginal digitiform glands, each with an independent, very slender initial portion; they are crown-shaped when there are more than three. With a sheath surroun ding the distal male duct (between the atrium and the penis retractor muscle insertion). With internal differentiation penis-epiphallus (ext ernally this differentiation can be undistinguishable). Penis retracto r muscle with an epiphallar insertion. Penial nerve originating from t he right cerebral ganglion (verified in the type and two additional sp ecies). Canariella is considered as ''incertae sedis'' within the Hygr omiidae and is compared with several other hygromiid genera without th e dart-sac complex. The most closely related genera are Montserratina, Ciliella (which is not present in the Canary Islands, in spite of pub lished records), Schileykiella, Tyrrheniellina and Ciliellopsis. Other Hygromiidae species lack dart-sac complex, but they differ in the pre sence of Vaginal appendages or in the morphology of the terminal parts of the male ducts.