Caldwellia H. Adams, 1873

Hyman, Isabel T. & Ponder, Winston F., 2010, A morphological phylogenetic analysis and generic revision of Australian Helicarionidae (Gastropoda: Pulmonata: Stylommatophora), and an assessment of the relationships of the family 2462, Zootaxa 2462 (1), pp. 1-148 : 81

Caldwellia H. Adams, 1873

Type species Helix philyrina Morelet, 1851 ( OD) . Mauritius.

Description. External morphology: Shell 4.1–4.4 whorls, not glossy, spire and apex raised. Protoconch sculptured with fine spiral lirae; teleoconch with spiral and radial lirae intersecting to form raised beads. Whorl profile flattened above and below keeled periphery ( Caldwellia imperfecta ) or rounded above and below an angulate periphery ( C. angularis ). Internal walls of early whorls complete; umbilicus closed. Mantle laps absent. Right and median mantle lobes small, left lobe absent. Sole of foot and caudal apparatus as for family; caudal horn large.

Mantle cavity: As for family. Mantle with ( C. angularis ) or without ( C. imperfecta ) visible minor blood vessels; pigmentation of white spots.

Digestive system: Oesophageal crop absent.

Genital system: As for family. Carrefour embedded in albumen gland, talon free (only examined in C. angularis ). Free oviduct of medium length ( C. imperfecta ) to long ( C. angularis ); capsular gland present; internally with longitudinal pilasters ( C. imperfecta ) or partially fused pustules ( C. angularis ). Bursa copulatrix inserted on vagina, moderately short, about half spermoviduct length; duct of bursa copulatrix wide, distinguishable from bursa copulatrix, internally with longitudinal pilasters. Vagina internally smooth ( C. imperfecta ) or with wavy longitudinal pilasters ( C. angularis ). Epiphallus enters penis through simple pore ( C. angularis ) or short verge ( C. imperfecta ); penis internally smooth, longitudinal penis pilasters present, apical diverticulum on penis absent ( C. angularis ) or present ( C. imperfecta ). Penial sheath present, enclosing only penis; muscle connecting top of penial sheath to epiphallus present; penis retractor muscle attached to base of epiphallic caecum ( C. imperfecta ) or to epiphallus ( C. angularis ). Epiphallic retractor caecum absent ( C. angularis ) or present ( C. imperfecta ). Flagellum present; flagellum and distal part of epiphallus without internal cryptae and externally smooth and slender. Spermatophore not present in dissected specimens.

Radula: Very wide, no lateral wrinkles, but central tooth area longitudinally shorter than rest of radula and tooth rows V-shaped. Central tooth with no ectocones; mesocone long, narrow, straight-sided, longer than tooth base. Lateral and marginal tooth fields indistinguishable. Latero-marginal teeth with endocones absent; ectocones approximately same length and breadth as mesocone, subdivided into three to five extra teeth.

Remarks. Caldwellia is found on Mauritius and Madagascar and contains 4–5 species ( Schileyko 2002b). No anatomical details are known for the type species, C. philyrina (Morelet, 1851) , but it shares with C. imperfecta and C. angularis the thin, keeled shell with very similar shape and sculpture ( Schileyko 2002b). The group was placed in Helicarioninae ( Helicarionidae ) by Zilch (1959) and in Trochozonitini ( Trochozonitinae , Ariophantidae ) by Schileyko (2002b).