Lactiforis tropicalis, Golding, Rosemary E., Ponder, Winston F. & Byrne, Maria, 2007

Golding, Rosemary E., Ponder, Winston F. & Byrne, Maria, 2007, Taxonomy and anatomy of Amphiboloidea (Gastropoda: Heterobranchia: Archaeopulmonata), Zootaxa 1476, pp. 1-50 : 15-16

Lactiforis tropicalis sp. nov.

Holotype ( Fig. 2 K): Australia, Western Australia: Broome, Roebuck Bay, on mudflats in front of mangroves, 24 Jun 1983, B. Jenkins (AMS C.446775).

Paratypes: Same data as holotype (AMS C.164311), 59 specimens.

Other material examined: Australia, Northern Territory: Maningrida , mudflats off beach, 27 Mar 1980, P.H. Colman (AMS C.446493); Darwin, East Arm, at boat ramp on surface of damp mud, 6 Jul 1988, W.F. Ponder (AMS C.445398). Australia, Queensland: Torres Strait, Saibai Island, Saibai Village, on mud in front of seaward mangroves, 8 Jul 1976, W.F. Ponder and I. Loch (AMS C.445405).

Etymology: Tropicalis (Latin) refers to the tropical distribution of this species in Northern Australia and Torres Strait.

Description: Shell ( Fig. 2 K): Fragile, spire short, conical, diameter to 7 mm, exterior smooth, axial striae faintly visible; umbilicus wide; sutures shallowly impressed. Exterior white to cream; umbilicus brownishorange.

Operculum ( Figs. 3 C, 4B): Thin, pale yellow, corneous with fan-shaped white deposit on interior surface around nucleus and along outer edge. Columellar edge of operculum curves inwards, outer edge rounded forming point in upper corner. Nucleus eccentric, paucispiral; exterior of operculum entirely corneous, with raised striae, white deposit visible from exterior.

External morphology: Head-foot lacking pigment in formalin-preserved specimens. Mantle white and mottled or spotted with black pigment in formalin-preserved specimens,

Digestive system: As for A. crenata , but proportionally smaller.

Mantle organs ( Fig. 7 C): Opposed ciliary tracts in mantle cavity short and restricted to exhalant canal; hypobranchial gland oval, flat, white in preserved specimens, positioned on roof of mantle cavity in exhalant canal; mantle roof slightly vascularised.

Radula ( Figs. 10 C, D): Central and lateral teeth absent, marginal teeth narrow, unicuspid, elongate, with recurved tips. Marginal teeth pointing towards centre of radula, approximately 25 on each side, forming very dense, indistinct rows.

Central nervous system ( Fig. 12 C): Large cerebral-pleural and pedal ganglia joined by short commissures. Left parietal ganglia reduced. Visceral loop concentrated with visceral ganglion abutting right parietal ganglion, separated from left parietal ganglion by commissure. Presence of parapedal and subcerebral commissures not determined.

Reproductive system ( Fig. 14 F): Ovotestis, oviductal and albumen glands as for A. crenata . Seminal vesicle a large diverticulum from upper hermaphrodite duct. Seminal receptacle small, elliptical, pigmented, opening via a short duct to carrefour. Spermoviduct running straight through right body wall distally, leading to hairpin fold in cephalic region before junction with proximal end of copulatory organ. Base of long prostatic gland vivid crimson red at junction with spermoviduct and spermovipositor. Spermovipositor short, simple with thick, tubular base; aperture of spermoviduct simple, thickened, fused distally to spermovipositor sheath forming narrow ridge towards genital aperture. Spermovipositor sheath bearing muscular flap on left of spermovipositor, lacking pockets. Possible spermatophore found in some specimens, globular, with red coating, lodged in spermovipositor sheath between spermovipositor and muscular projection from wall.

Distribution and habitat ( Fig. 1 ): Northern Australia, recorded from Broome (Western Australia) to the Torres Strait (northern Queensland), although based on few available records. It is assumed that L. tropicalis sp. nov., which occurs in both the Torres Strait and Broome, has a more-or-less continuous distribution between these sites, despite the lack of records from the Gulf of Carpentaria and the western coast of Cape York. It is found on estuarine and coastal mudflats.

Remarks: Lactiforis tropicalis sp. nov. has obvious similarities with L. takii (see generic diagnosis), but is distinguished from that species by the crimson prostatic gland and white shell with coloured umbilicus. The tropical Australian distribution of L. tropicalis is very different from that of L. takii , which is found only in Japan.

Figures

FIGURE 1. Distributions of amphiboloidean species determined from the present study and previous reports. Species in bold are examined in this paper.

FIGURE 2. Shell morphology of species in Amphibolidae, Phallomedusidae fam. nov. and Maningrididae fam. nov .. A. Amphibola crenata (Martyn, 1786), (AMS C. 446522). B – D. Salinator fragilis (Lamarck, 1822), B. Lectotype (MHN 1094 / 1), C. Albany, Western Australia (AMS C. 446486), D. Cambridge, Tasmania (AMS C. 442291). E. Salinator tecta sp. nov .. Holotype, Narrabeen Lakes, Sydney (AMS C. 446774). F. Salinator rhamphidia sp. nov .. Holotype, Botany Bay, Sydney (AMS C. 446516). G. Salinator rosacea sp. nov .. Holotype, Elizabeth River, Darwin (AMS C. 446519). H, I. Phallomedusa solida (Martens, 1878), H. Holotype (ZMB 22207), I. Lake Illawarra, New South Wales (AMS C. 442239). J. Phallomedusa austrina sp. nov .. Holotype, Stanley, Tasmania (AMS C. 446510). K. Lactiforis tropicalis sp. nov .. Holotype, Broome, Western Australia (AMS C. 446775). L. Lactiforis takii (Kuroda, 1928). Ariake Sea, Japan (AMS C. 446490). M. Naranjia cf. swatowensis (Yen, 1939). Tsim Bei Tsui, Hong Kong (AMS C. 446511). N. Maningrida arnhemensis sp. nov .. Holotype, Maningrida, Northern Territory (AMS C. 446485). Scale bar = 2 mm.

FIGURE 3. Internal surfaces of opercula. A. Amphibola crenata (Martyn, 1786). B. Salinator fragilis (Lamarck, 1822). C. Lactiforis tropicalis sp. nov .. D. Phallomedusa solida (Martens, 1878). E. Maningrida arnhemensis sp. nov .. Scale bar = 2 mm.

FIGURE 7. Morphology of organs in the mantle cavity. A. Amphibola crenata (Martyn, 1786). B. Salinator fragilis (Lamarck, 1822). C. Lactiforis tropicalis sp. nov .. D. Naranjia cf. swatowensis (Yen, 1939). E. Phallomedusa solida (Martens, 1878). F. Maningrida arnhemensis sp. nov .. Scale bar = 1 mm.

FIGURE 10. SEM photographs of radulae of Amphibola Schumacher, 1817, Lactiforis gen. nov. and Naranjia gen. nov. species, showing half-radula and detail of central and lateral teeth. A, B. Amphibola crenata (Martyn, 1786). C, D. Lactiforis tropicalis sp. nov .. E, F. Lactiforis takii (Kuroda, 1928). G, H. Naranjia cf. swatowensis (Yen, 1939). A, C, E, G. Scale bar = 50 µm, B, D, F, H. Scale bar = 20 µm.

FIGURE 12. Central nervous systems. A. Amphibola crenata (Martyn, 1786). B. Salinator fragilis (Lamarck, 1822). C. Lactiforis tropicalis sp. nov .. D. Lactiforis takii (Kuroda, 1928). E. Naranjia cf. swatowensis (Yen, 1939). F. Phallomedusa solida (Martens, 1878). G. Maningrida arnhemensis sp. nov .. Scale bar = 500 µm. Subcerebral and parapedal commissures are indicated on the figures for A. crenata, S. fragilis and P. s o l i d a, but not on the figures for other species as the presence of these structures is unconfirmed.

FIGURE 14. Distal reproductive structures of Amphibolidae. Structures orientated with proximal region at top of figure and distal region including genital aperture at base of figure. In all figures the dorsal part of the spermovipositor sheath has been removed, showing the spermovipositor, and in Figs. 13 A – C, E and H the distal portion of the prostatic gland is not shown. A. Salinator fragilis (Lamarck, 1822). B. Salinator tecta sp. nov .. C. Salinator rhamphidia sp. nov .. D. Salinator rosacea sp. nov .. E. Naranjia cf. swatowensis (Yen, 1939). F. Lactiforis tropicalis sp. nov .. G. Lactiforis takii (Kuroda, 1928). H. Amphibola crenata (Martyn, 1786). A, B, C. Scale bar = 1 mm, D, E, F, G, H. Scale bar = 500 µm.