Parglogenia pelodes (Pfeiffer, 1846)

Koehler, Frank & Shea, Michael, 2022, A new cryptic species of land snail from the Northern Territory, Australia (Stylommatophora, Camaenidae, Parglogenia), Zoosystematics and Evolution 98 (2), pp. 427-433 : 427

Parglogenia pelodes (Pfeiffer, 1846)

Helix pelodes Pfeiffer, 1846: 126 ('north coast of Australia’). Neotype FMNH 182450, Darwin, Dudley Point (12°24'S, 130°49'E), designated by Köhler (2012).

Helix prunum - Pfeiffer 1851 [in 1849-1853]: 54, pl. 74, figs 11-13; Reeve 1852 [in 1851-1854]: pl. 68, fig. 353; Cox 1868: 43, pl. 4, fig. 6 (not Helix prunum Férussac, 1821).

Chloritis pseudoprunum Pilsbry, 1893: 271 ('Port Darwin’; Holotype ANSP 62411).

Parglogenia pelodes - Iredale 1938: 99; Solem 1979: 128-133, fig. 32, pls 11a, b.

Taxonomic remarks.

Since its original description, the name Helix pelodes has been shrouded in uncertainty until relatively recently. Pfeiffer (1851 [in 1849-1853]), subsequently treated H. pelodes as a junior synonym of Helix prunum Férussac, 1821. Subsequently, Pilsbry (1890: 135) agreed with this synonymy, but accepted H. prunum as an eastern Australian species with uncertain systematic relationships. Based on this presumption, he considered that all previous authors had misapplied the name H. prunum for an unnamed species from Arnhem Land, for which Pilsbry (1893) introduced the new name Chloritis pseudoprunum . By contrast, Iredale (1938) and Solem (1979) considered that the supposed synonymy of H. pelodes with H. prunum was in error. While H. prunum continues to be a taxonomic enigma to this date ( Köhler 2012), Helix pelodes was removed from its synonymy and treated as an accepted species, for which Iredale (1938) described the genus Parglogenia . This treatment rendered C. pseudoprunum a junior synonym of P. pelodes . Iredale (1938) included a second species in this genus, P. subgranosa (Le Guillou, 1842). Köhler (2012) rejected this treatment, arguing that the type of Helix subgranosa represented a juvenile shell of Xanthomelon durvillii (Hombron & Jacquinot, 1841). However, Köhler (2012) maintained H. subgranosa as a nomen inquirendum. To remove the remaining ambiguity, Helix subgranosa is herewith placed in the synonymy of X. durvillii .

Diagnosis.

Shell relatively large (D = 14.3-31.5 mm, H = 10.8-20.3 mm; n = 92), with strongly and almost evenly elevated spire, comprising between 4.5 and 5.8 whorls. Apical sculpture of anastomosing ridges initially, becoming pustulated after first half whorl. Postapical whorls with microsculpture of very small, rather widely spaced setae and extremely fine ridgelets with weak radial ribs appearing on spire and body whorl. Umbilicus very narrow, partly covered by reflected lip, internally with crowded pustules. Body whorl globose, rounded, only slightly descending behind strongly reflected, thin, white lip. Shell light yellow brown, uniform. Vagina and penis very long, atrium short, bursa copulatrix very short, without enlarged head. Free oviduct with glandular, convoluted walls. Vas deferens with bifurcated caecum on ascending arm and entering the epiphallus near insertion of penial retractor muscle without differentiation. A narrow, raised ridge separates the epiphallus from the penis; inner penial walls with longitudinal corrugated ridges; no penial sheath, verge, or epiphallic appendages present ( Solem 1979; Köhler 2012).

Comparative remarks.

Solem (1979) provided a detailed description of the shell and reproductive anatomy of this species based on examination of specimens from near Darwin. He remarked that the periostracal setae in P. pelodes were similar to those in Semotrachia , Austrochloritis and " Chloritis argilacea " (presently Parachloritis argilacea ; see Köhler and Kessner 2014), but that the genital anatomy of Parglogenia was highly distinctive. Köhler (2012) illustrated the reproductive anatomy of a specimen of P. pelodes from Melville Island, which closely resembled that of specimens from Darwin. Shells of P. pelodes , including the holotype of Chloritis pseudoprunum , have been figured by Köhler (2012).