Coneuplecta Moellendorff, 1893

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 : 107-108

Coneuplecta Moellendorff, 1893

Coneuplecta Moellendorff, 1893: 64 . Type species Helix scalarina Pfeiffer, 1851 [nom. nov. for Helix gradata Pfeiffer, 1846 non Gould, 1846] (SD Moellendorff, 1898). Island of Leyte, Pacific.

Description. External morphology: Shell 4.1–5.1 whorls, not glossy, spire and apex raised. Shell not glossy. Protoconch sculptured with spiral and radial ribs ( Coneuplecta calculosa , C. pampini ) or spiral grooves ( C. dahli ); teleoconch with spiral and radial lirae. Whorl profile flattened above and below evenly convex periphery. Internal walls of early whorls complete; umbilicus closed. Mantle laps and lobes absent. Sole of foot tripartite; caudal apparatus formed from curled up sole ( Muratov’s 1999 helicarionid type); caudal foss horizontal slit in tail.

Mantle cavity: Kidney unilobed; mantle with no visible minor blood vessels, pigmentation of black and white spots ( C. calculosa ), numerous white spots ( C. pampini ) or absent ( C. dahli ), mantle gland present ( C. calculosa ) or absent ( C. dahli ) (not examined in C. pampini ).

Digestive system: Oesophageal crop absent.

Genital system: Oviparous; carrefour and talon both not embedded in albumen gland. Oviduct glandular. Free oviduct long to very long; capsular gland present ( C. calculosa ) or absent ( C. pampini ) (not examined in C. dahli ); internal longitudinal pilasters absent. Bursa copulatrix inserted on vagina, very short, shorter than free oviduct ( C. calculosa , C. dahli ) or short, approximately equal in length to free oviduct ( C. pampini ); duct of bursa copulatrix wide, not distinguishable from bursa copulatrix ( C. calculosa ) or narrow, distinguishable from bursa copulatrix ( C. pampini , C. dahli ). Vagina very short ( C. dahli ) or short ( C. calculosa , C. pampini ), internally smooth. Stimulator absent ( C. dahli , C. pampini ) or basal diverticulum on penis (vestige of stimulator?) present ( C. calculosa ). Epiphallus enters penis through simple pore ( C. calculosa , C. dahli ) or verge ( C. pampini ), penis internally smooth ( C. calculosa , C. pampini ) or with ridges ( C. dahli ), pilasters absent. Penial sheath present, enclosing only penis. Epiphallus shorter than ( C. calculosa , C. dahli ) or longer than ( C. pampini ) penis. Epiphallic retractor caecum absent. Flagellum and lime-sac absent. Spermatophore not present in dissected specimens.

Radula ( C. calculosa , C. pampini only): Wide, with no lateral wrinkles. Central tooth with large ectocones and two smaller accessory cusps ( C. calculosa ) or with small, high, triangular ectocones ( C. pampini ); mesocone long and narrow, shorter than tooth base. Two ( C. calculosa ) to no ( C. pampini ) lateral teeth present, distinguished from marginals only by presence of endocones; marginal teeth with endocones absent; ectocones approximately same length and breadth as mesocone, subdivided into 2–5 extra teeth, increasing in number towards the outer edge ( C. calculosa ) or ectocones not subdivided but with 5–9 serrations, increasing in number and becoming deeper towards outer edge ( C. pampini ).

Remarks. As outlined by Solem (1988), Coneuplecta was redefined by Baker (1941a) who included in it several subgenera, including Durgellina Thiele, 1928 and Conibycus Thiele, 1928 , all with somewhat diverse shells but similar anatomical features. Solem (1988) followed this usage. This arrangement is tentatively followed here.

Nevelasta was named for Helix pampini Cox, 1868 and Helix (Conulus) liardeti Brazier, 1872 ( Iredale 1937c) . The type of the latter species is missing and it was placed under incertae sedis by Smith (1992), effectively leaving Nevelasta as a monotypic genus. Nevelasta was originally placed in the family Durgellidae along with Turrisitala Iredale, 1933 , Sodaleta Iredale, 1937 and Eclipsena Iredale, 1937 ( Iredale 1937c) . It was placed in Helicarionini (Helicarioninae, Helicarionidae ) by Schileyko (2002b) based on shell details.

The Australian species Nevelasta pampini is included in Coneuplecta s.l. based on similarities in its shell, anatomy and radula to Coneuplecta calculosa , C. microconus (Mousson, 1865) and C. turrita palauensis Baker, 1941 . The distinctive wide radula with V-shaped tooth rows and small to absent lateral tooth fields is seen in these members of Coneuplecta ( Baker 1941a; this study). However, C. (N.) pampini differs from the other taxa in the presence of a tricuspidate rather than a pentacuspidate central tooth, two cusps and minor serrations on the latero-marginal teeth rather than four to five, and more rounded cusps ( Figure 40A–C ). For this reason this species is tentatively retained in the subgenus Nevelasta .

In the phylogenetic analysis, the three species included in Coneuplecta always grouped together ( Figures 1–3 ) and formed the most basally diverging taxon in the ingroup.

Figures

FIGURE 1. Majority-rule consensus tree (1,743 trees, length 117 steps) from the morphological analysis containing representatives of all groups. Families and subfamilies are shaded and are labelled in bold if the group is not monophyletic.

FIGURE 2. Majority-rule consensus tree (646 trees, length 106 steps) from the morphological analysis with Dyakiidae and Urocyclidae excluded. Families and subfamilies are shaded and are labelled in bold if the group is not monophyletic.

FIGURE 3. Majority-rule consensus tree (770 trees, length 117 steps) resulting from the morphological analysis with two additional mantle lobe characters. Families and subfamilies are shaded and are labelled in bold if the group is not monophyletic.

FIGURE 40. Radulae. SEM. A–C. Coneuplecta pampini, AM C438751. D–F. Coneuplecta calculosa, AM C377891. G–I. Liardetia doliolum, BPBM 253684. J–L. Lamprocystis guttula, FMNH 174940. Scale bars 10 mm (A–I), 20 mm (J–L).