Pravonitor Iredale, 1937

Hyman, Isabel T. & Köhler, Frank, 2022, Homoplasy in shells discombobulated the taxonomy: revision of the larger helicarionid land snails of northern Queensland, Australia (Stylommatophora: Helicarionidae), Journal of Natural History 56 (41 - 44), pp. 1727-1799 : 1771-1772

Pravonitor Iredale, 1937

Pravonitor Iredale, 1937: 3 .

Type species Nitor kreffti insularum Iredale, 1937 (by original designation).

Differential diagnosis

External appearance. Shell medium-sized to large (SW 10–21 mm), pale gold to amber, sometimes with an amber supraperipheral band, lower half of shell often slightly darker in colour, glossy, 5–6.4 whorls, subdiscoidal to subglobose, whorls subangulate to rounded. Protoconch and teleoconch with very fine spiral grooves, sometimes becoming obsolete on teleoconch. Body colour cream to brown (in alcohol). Mantle lobes moderately small; shell lappets long, triangular, wide at base, tapering to a point. Caudal horn large.

Genital anatomy. Ovotestis of 4–8 lobes, embedded in digestive gland. Carrefour visible; talon usually embedded in albumen gland. Spermoviduct not folded. Free oviduct long, with elongate capsular gland; free oviduct internally sculptured with longitudinal pilasters. Vagina short, sculptured internally with longitudinal pilasters. Bursa copulatrix moderately short to moderately long, inserted on the vagina, base of duct usually swollen, then narrowing; bursa elongate. Penis short and broad to long and slender, internally pustulose, with or without longitudinal pilasters, or with longitudinal pilasters only ( P. ferruginea only). Penis tunica attached by muscle fibres to middle of epiphallus; epiphallus enters penis through simple pore or small verge; epiphallus 2 longer than epiphallus 1; epiphallic caecum moderately long to long, penial retractor muscle attached to middle of caecum. Long, slender epiphallic flagellum with axial filaxment present; internal cryptae generally minor and not visible externally (except in P. annulus ). Spermatophore a softwalled capsule with hard tail-pipe; capsule with elongate tip; tail-pipe smooth, or sculptured with fine, hair-like spines.

Remarks

Pravonitor was first introduced as a subgenus of Nitor for two species from Far North Qld, Helix kreffti Cox, 1864 and Nitor kreffti insularum Iredale, 1937 ( Iredale 1937) , on the basis of their rounded rather than angulate or keeled shell periphery and their ‘different’ shell texture. Pravonitor was raised to generic status by Smith (1992), who also synonymised P. kreffti and P. kreffti insularum . Hyman and Ponder (2010) demonstrated that Pravonitor could also be clearly separated from Nitor based on anatomical data. Most recently, Stanisic et al. (2010) included in this genus Helix villaris Reeve, 1854 (previously considered a synonym of Expocystis rustica Iredale 1937 ; Smith, 1992) and two new species, Pravonitor laura and Pravonitor ferrugineus .

In the current study we have determined that P. laura and P. villaris are not closely related to the type species of this genus, P. insularum (herein removed from synonymy with P. kreffti ) but instead group with two undescribed species from Far North Qld. These two species are henceforth placed in the new genus Geminitor . In addition to P. insularum , P. kreffti and P. ferrugineus , we include in Pravonitor two species previously belonging to Malandena , M. aquilonia Stanisic, 2010 and M. monteithi Stanisic, 2010 . We also describe P. septentrionalis from Cape York and P. stuarti from High Range, and reinstate P. annulus , previously listed as incertae sedis ( Smith et al., 2002), bringing the total species count for this genus to eight.

Pravonitor can be characterised by its medium-sized to large, highly glossy shell, with very fine to obsolete spiral microsculpture, often with a peripheral band, subdiscoidal to subglobose in shape, with a rounded to subangulate whorl profile. Anatomically, defining characters include the short vagina, elongate free oviduct, long, slender bursa copulatrix with a basally broadened duct, long epiphallic caecum with medial attachment of the penial retractor muscle, slender flagellum, sometimes with distinct internal cryptae (most pronounced in P. annulus ), and generally pustulose penis interior. The spermatophore consists of a soft, elongate capsule with a long tail-pipe, sometimes smooth ( P. monteithi ), sometimes sculptured with hook-like spines (short in P. kreffti , longer in P. annulus ). In P. annulus , both the flagellum and the spermatophore tail-pipe form a spiral.