Parmacochlea Smith, 1884

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 : 56-57

Parmacochlea Smith, 1884

Parmacochlea Smith, 1884: 273 . Type species Parmacochlea fischeri Smith, 1884 (M).

Description. External morphology: Shell reduced, 1.7–2 whorls, glossy, spire and apex flattened. Protoconch and teleoconch smooth. Whorl profile rounded above and below evenly convex periphery. Internal walls of early whorls incomplete; umbilicus not visible. Mantle laps very large, almost completely fused, leaving a small opening through which the shell is visible, uniform in colour. Right mantle lobe of medium size; median and left mantle lobes extremely large, fused to form long lobe over head. Sole of foot and caudal apparatus as for family; caudal horn extremely small; caudal foss a very large vertical slit in tail.

Mantle cavity: As for family. Mantle with visible minor blood vessels, pigmentation absent.

Digestive system: Oesophageal crop very large.

Genital system: As for family. Talon and carrefour not examined. Free oviduct long; internal transverse pilasters present. Bursa copulatrix inserted at junction of penis and free oviduct; duct of bursa copulatrix narrow, distinguishable from bursa copulatrix, internally with longitudinal pilasters. Vagina absent. Epiphallus enters penis through short verge; penis internally smooth, one longitudinal penis pilaster present, penial diverticulum absent. Penial sheath present, enclosing only penis; penis retractor muscle attached to base of epiphallic caecum. Epiphallus internally with longitudinal pilasters. Epiphallic retractor caecum moderate in size, positioned in middle of epiphallus. Flagellum present; flagellum and distal part of epiphallus without internal cryptae and externally smooth and slender. Vas deferens extremely long and highly coiled. Spermatophore not present in dissected specimen.

Radula: Relatively long and narrow. Central tooth with small ectocones; mesocone lanceolate, slightly longer than tooth base. Lateral and marginal tooth fields distinguishable. Lateral teeth with endocone much smaller than central tooth ectocones; ectocone equal in size to those on central tooth; mesocone longer than tooth base. Marginal teeth with endocones absent; ectocones shorter and narrower than the mesocone, not subdivided into extra teeth.

Remarks. In this genus, two species from northern Queensland, Parmacochlea fischeri (Cape York) and P. smithi Simroth, 1898 (Cooktown) are recognised by Smith (1992). Thularion semoni (Martens, 1894) was also included in Parmacochlea by Iredale (1937c), but was moved into a separate genus by Stanisic (1993b).

No anatomical data was given for P. fischeri when it was first described ( Smith 1884). Parmacochlea smithi was differentiated from P.fischeri based on differences in the shape of the foot, the presence of dermocalcite in the surface of the mantle lobes and the presence of points or tips (‘zipfels’) on the left mantle lobe.

The specimen examined here appears to have genitalia identical to P. smithi , illustrated by Simroth (1898). However, the distinguishing features of P. smithi (‘zipfel’ on the left mantle lobe and the presence of dermocalcite) were not observed, leading the specimen to be identified as P. fischeri . It is possible that P. fischeri and P. smithi should be synonymised; however, a close comparison of the two species was not possible in the current study. It should be noted that the specimens examined had been preserved in ethanol for 25–30 years, which could lead to some of the characters being lost (e.g., dermocalcite particles in the mantle dissolving).

Parmacochlea fischeri can be easily distinguished from all other species in the current study by the extreme shell reduction it exhibits, as well as the large size and high degree of fusion of the mantle laps and lobes. Anatomically, P. fischeri differs from the other northern Australian semislugs by its lack of a distinct vagina and its extremely long and highly coiled vas deferens.