Parmavitrina planilabris (Cox, 1866)
Vitrina planilabris Cox, 1866: 45-46 [Holotype missing, presumed lost].
Helicarion macgillivrayi: Tryon, 1885: 171, pl. 39, figs 67-68.
Material examined. Non-type material. See Table S1.
Diagnosis. Shell. Large, 3.4-3.8 whorls, amber, ear-shaped, flattened; last whorl large and flared with membraneous base; shell glossy, protoconch sculptured with fine spiral grooves, teleoconch sculptured with very fine, almost indistinct spiral grooves (Table 3, Figs 22A, 23A-C).
Animal. Grey with darker spots and orange-red mucus, mid field of sole paler than outer fields, sides of sole striped, slime network prominent, tail strongly keeled, caudal gland small. Mantle lobes moderate size, left and median lobes fused; shell lappets broad but moderately small, rounded, pustulose (Fig. 24A).
Genitalia. Bursa copulatrix short, equal in length to free oviduct, sac spherical to tear-shaped. Penis large, often very swollen at proximal end, sometimes not fully covered by penial tunica. Penis interior with irregular pilasters, ridged, primarily longitudinal at distal end, breaking up into irregular pilasters or pustules at proximal end. One pilaster often greatly swollen towards proximal end. Epiphallus relatively short, approx. 1-1.5 x penis length, containing internal cryptae near flagellum; entering penis through thickened ring. Epiphallic flagellum with internal cryptae and long, slender tail. Spermatophore not observed (Fig. 25).
Remarks. The species has been described from “Mitchell River, NSW”; the holotype is presumed lost. Parmavitrina planilabris is distributed from Buladelah in mideastern NSW to the New England Tableland in northern NSW in rainforest and wet sclerophyll forest (Fig. 26). This species has a unique genital anatomy consisting of a large, proximally swollen penis with no penial verge and irregular penial pilasters. It can be distinguished from the similarly sized P. disposita, with which it is sympatric around Chichester, by its grey colouration and shell with a membraneous base.
Fig. 26. Occurrence records of Parmavitrina species from the malacological collection of the Australian Museum, Sydney. Symbols: □ = P. planilabris, ● = P. megastoma, = P. rubrica, + = P. flavocarinata, ♠ = P. maculosa, ♦ = P. disposita.
This species is phenotypically similar and phylogenetically closely related to P. rubrica. Both taxa differ from each other by p-distances of 2.4-3.6% in 16S and 5-6% in COI, which are near the boundary between intra- and interspecific distances. It is possible that P. rubrica should not be retained as a separate species and merely represents a southern range extension of P. planilabris. However, there are several differences between the two taxa. Parmavitrina rubrica is slightly smaller, with a more orange-brown colouration; it does not have fused mantle lobes; it has a smaller, more tubular penis with a penial verge, internally with deep, zigzagging or wavy longitudinal pilasters. In contrast, P. planilabris is larger, more grey in colouration, with fused mantle lobes; it has a proximally swollen penis with a short penial tunica, no penial verge, and less distinct, broad, shallow, ridged pilasters breaking up into irregular pilasters or pustules proximally. Given the small but distinct morphological differences between the two taxa we retain P. rubrica as separate species.