Lamarckiella lamarckiana sibuyanensis Bartsch, 1939

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 : 105

Lamarckiella lamarckiana sibuyanensis Bartsch, 1939

Figure 39B

Material examined. Philippines: FMNH 201967 (one specimen dissected), NW slope Mt. Guitinguitin , Sibuyan F., Romblon Prov., secondary growth, lowland forest, 325 m, 8 May 1989, S.M. Goodman .

Description. External morphology: Shell 5 whorls, orange-brown, not glossy, spire and apex slightly raised. Whorl profile flattened above and below an angular periphery. Internal walls of early whorls complete; umbilicus closed. Mantle laps and lobes, sole of foot and caudal apparatus not examined due to poor preservation.

Genital system ( Figure 39B ): Oviparous; oviduct glandular. Free oviduct short; capsular gland not examined; internal structure not examined. Bursa copulatrix inserted on vagina; duct of bursa copulatrix moderately wide, distinguishable from bursa copulatrix, internal structure not examined. Vagina very short. Penis moderately long; epiphallus enters penis through a medium verge, half length of penis; penis internally flat, at least three longitudinal penis pilasters present, penial diverticulum absent. Penial sheath present, enclosing penis and part of epiphallus, closed at distal end; penis retractor muscle attached to epiphallus. Epiphallus longer than penis. Epiphallic retractor caecum absent; Flagellum and lime-sac absent. Spermatophore not present in dissected specimen.

Radula: Not examined.

Remarks. Lamarckiella is distributed through the Philippines and parts of Indonesia, and is represented by 12–14 species and forms ( Schileyko 2002a). This genus appears to be closely related to Ryssota ( Schileyko 2002a) , one of the genera that Solem (1966) suggested may be part of the true Helicarionidae . Ryssota was placed in Chronidae (Gastrodontoidea) by Hausdorf (1998) based on the presence of a thick-walled spermatophore and distinct minor venation on the roof of the mantle cavity. However, these characters are also shared by most Helicarionidae .

Schileyko (2003a) placed Ryssota and Lamarckiella in his new family Ryssotidae (Helicarionoidea) , along with several other genera from China, Malaysia, the Philippine and Caroline Islands and Indonesia. According to Schileyko (2003a), the family can be distinguished from all other Helicarionoidea by the unusually large shell, undivided sole and the absence of additional organs of the reproductive tract, and may be a distant relative of Trochomorphidae .

In the current study, only a single specimen was available for examination and some features could not be observed. Lamarckiella exhibits a simple reproductive tract with no stimulator or epiphallic diverticulae; however, these features could have been lost in this group and do not necessarily exclude Lamarckiella from Helicarionoidea . This species was not included in the phylogenetic analysis due to missing data.

Figures

FIGURE 39. Reproductive systems. A. Everettia sp., BMNH 20020188. B. Lamarckiella lamarckiana sibuyanensis, FMNH 201967. C. Coneuplecta pampini, AM C438751. D. Coneuplecta calculosa, AM C377891. E. Coneuplecta dahli, MNHN no registration number. F. Hiona pilsbryi, BPBM 206801. G. Liardetia doliolum, BPBM 253684. Scale bars 1 mm (C–E, G), 2 mm (F), 5 mm (A–B). Abbreviations: alb, albumen gland; bc, bursa copulatrix; ca, carrefour; e, eggs / embryos; ep, epiphallus; fov, free oviduct; her, hermaphrodite duct; m, muscle attaching penial sheath to epiphallus; ov, ovotestis; p, penis; pd, penial diverticulum; pr, prostate; prm, penis retractor muscle; pt, penial sheath; pv, penial verge; st, stimulator; ut, uterus; v, vagina; vd, vas deferens.