Pseudotricula eberhardi Ponder, 1992

Ponder, W. F., Clark, S. A., Eberhard, S. & Studdert, J. B., 2005, A radiation of hydrobiid snails in the caves and streams at Precipitous Bluff southwest Tasmania, Australia (Mollusca: Caenogastropoda: Rissooidea: Hydrobiidae s. l.),, Zootaxa 1074 (1), pp. 1-66 : 11-15

Pseudotricula eberhardi Ponder, 1992

Figures 2A ; 3A, B ; 4A .

Synonymy

Pseudotricula eberhardi Ponder, 1992: 26 , plate 1A–H, fig. 1A,B, fig. 2A,B, fig. 3A–C; Kierman &

Eberhard, 1990, pl. 3.1.

Type material

Holotype: AMS C.165052, Black Curtain Streamway, Cueva Blanca, PB 4, 31 MAR 1986.

Paratypes: AMS C.165053, same data (1 dry, 3 wet) , TMAG E20151 ; AMS C.165054, same locality, 18 Dec. 1988 (9 dry, 20+ wet) ; TMAG E20152 .

Other material examined

Cueva Blanca: AMS C.165390, PB4 (1 dry topotype); AMS C.203693, Black Curtain Streamway, PB4­1C (12 dry, 14 wet).

Description

Shell ( Fig. 1A ). Length up to 2.8 mm; broadly conical ( SW /SL 0.71–0.80, mean 0.74, n = 10); spire low to moderate, straight to slightly convex in outline; last whorl evenly rounded; suture narrowly channelled; otherwise whorls evenly convex. Protoconch microsculpture small pits and pustules, with some weak spirally arranged wrinkles. Teleoconch up to 2.6 whorls in adult; aperture oval to pear­shaped; large, longer than spire (AL/SL 0.57–0.68, mean 0.63, n = 10); outer lip prosocline, straight to slightly sinuous, with strong reflection; external varix absent; notch present in posterior corner of aperture; inner lip moderately thickened to thick and broad, adhering to, or narrowly separated from, parietal wall.

Dimensions. See Table 2.

Operculum. Yellowish; inner surface with white smear.

Pallial cavity. Ctenidium narrow; 9–13 very small filaments; osphradium between posterior end and middle of ctenidium; hypobranchial gland moderately developed; renal organ extends forward ca. ½ into pallial cavity; pericardium ½ in pallial roof.

Radula ( Fig. 3A, B ). Central teeth ( Fig. 3B ): dorsal edge with shallow indentation; 5 lateral cusps, median cusp of medium width, sharply pointed, less than twice as long as adjacent cusps. Lateral teeth: dorsal edge straight to lightly convex; with 3 cusps on inner and 4 on outer side; median cusp of medium width, sharply pointed, less than twice as long as adjacent cusps; ratio of cutting edge to shaft about ⅓–½; basal projection bluntly pointed. Marginal teeth: Inner with 15–17 cusps; outer with 14–20 cusps.

Stomach. Stomach with posterior chamber a little smaller than anterior chamber.

Male genital system. Testis of about 1 whorl; prostate gland oval to elongate pyriform; oval in section; pallial vas deferens straight to slightly undulating. Penis ( Fig. 3A ) with very weak swelling in mid­distal portion (hardly apparent); distal end tapering, similar to “papilla” in other taxa, medial section tapering; of medium length; penial duct in medial section of penis almost straight to undulating; base of penis moderately wide, with moderate folds; penial duct straight to undulating.

Female genital system. Ovary of 0.5–1.0 whorls; oviduct extends to posterior edge of bursa copulatrix; joins bursal duct at posterior pallial wall. Bursa copulatrix of medium size, not extending to posterior pallial wall; globular; with bursal duct arising from middle of anterior edge of bursa to antero­ventral edge; straight, wider at bursal end. Seminal receptacle at middle of inner wall of bursa copulatrix; pyriform. About ½ to more than ½ of albumen gland in front of posterior pallial wall; capsule gland about same to about ⅔ length of albumen gland; circular to oval in section; anterior end blunt; ventral channel simple, approximately parallel­sided throughout; vestibular area indistinct; genital opening subterminal.

Distribution and habitat

Found only on smooth rock surfaces in fast­flowing falls and streams in Cueva Blanca.

Remarks

Pseudotricula eberhardi has only been found in very strongly flowing water in Cueva Blanca. A record of this species from Persephone Pot ( Ponder 1992) are specimens of P. expandolabra n. sp. This species is distinguished from other congeners by its short, slightly convex spire and evenly convex whorls.

Figures

FIGURE 1. Schematic plan of mapped caves (black outline) at Precipitous Bluff showing hydrologic relationships (arrows indicate direction of stream flow paths), sample sites (numbered), cave entrances (black dots), and locations mentioned in text. Adapted from Hume (1989). Inserts: A, Tasmania with location of Precipitous Bluff (PB in boxed area), Ida Bay (IB), Hastings (H), Vanishing Falls (VF) and Cracroft (C); B, Precipitous Bluff and New River Lagoon showing surface sample sites (numbered) and location of the caves (boxed area) in relation to dolines (open circles) with sinking streams that feed Damper Cave and Quetzalcoatl Conduit, which becomes Damper Creek upon resurging at the surface. Also shown (in B) is Precipitous Bluff. The numbers shown in B are explained below. The arrows in insert B and the main figure show the direction of water flow. In the main map, the “PB” prefixed numbers refer to cave entrance numbers used by the Australian Speleological Federation. Sample sites shown in both the main map and in insert B are numbered as follows: 1 Bauhaus Cave (PB6) base of aven (stn PB6­1) and main streamway at downclimb (PB6­1A); 2 Bauhaus Cave (Persephone Pot PB17) lower streamway at first contact with stream stn 7; 3 Bauhaus Persephone middle streamway stn 8; 4 Bauhaus Persephone middle streamway stn 9; 5 Bauhaus Persephone upper streamway stn 10; 6 Bauhaus Screaming Stals streamway stn 11; 7 Bauhaus Screaming Stals streamway stn 12; and tributary seep near stn 12; 8 Bauhaus Screaming Stals streamway stn 13; 9 Cueva Blanca (PB4), Black Curtains streamway (=Inundation Passage); 10 Damper Cave (PB1) main streamway ca. 50 m inside entrance; 11 Damper Cave main streamway 100 m into cave; 12 Damper Cave, Honey and Cream; 13 Damper Cave seep near The Keg; 14 Damper Cave, Cane Toad Abuse; 15 Quetzalcoatl Conduit (PB3), 30 m into cave, stn PB3­ 1C; 16 Quetzalcoatl Conduit, beyond Pendulum Palace, stn PB3­2; 17 Damper Creek, 10 m downstream of Damper Cave entrance; 18 Damper Creek, first crossing; 19 Damper Creek at New River Lagoon; 20 Malani Creek; 21 Limestone Creek near New River Lagoon.

FIGURE 2. Shells of Pseudotricula species. A, Pseudotricula eberhardi, holotype, C.165052, Black Curtain Streamway, Cueva Blanca; B–E, Pseudotricula expandolabra, B, holotype, C.439673, Persephone Streamway, Bauhaus; C, paratype, C. 439674, Persephone Streamway, Bauhaus; D, C.201811, Persephone Pot, Bauhaus; E, C201495, Persephone Streamway, Bauhaus; F, Pseudotricula auriforma, holotype, C.439672, main streamway, Damper Cave. Scales: A F, 500 m.

FIGURE 3: Radulae of Pseudotricula species. A, B, Pseudotricula eberhardi, C.165053, Black Curtain Streamway, Cueva Blanca; C–H, Pseudotricula expandolabra, C, D, C.201495, Persephone Streamway, Bauhaus, E, G, H, C.201811, Persephone Pot, Bauhaus, F, C.201822, main streamway, Bauhaus; I, Pseudotricula arthurclarkei, C.203671, paratype, Quetzalcoatl Conduit; J–L, Pseudotricula conica, C.203676, paratype, Cane Toad Abuse Streamway, Damper Cave. A, C, G, K, central, lateral inner and outer marginal teeth; B, E, L, central teeth; D, outer marginal teeth; F, J, lateral and inner marginal teeth; H, lateral tooth; I, central and lateral teeth. Scales: A, B, E, H–J, L 10 m; C, F, G, K, 20 m; D, 5 m.

FIGURE 4. Dorsal views of penes of Pseudotricula and Nanocochlea species. A,. Pseudotricula eberhardi; B, Pseudotricula expandolabra; C, Nanocochlea stylesae; D, Nanocochlea damperensis; E, Pseudotricula conica. Scales A, B, E, 0.2 mm; C, D, 0.1 mm. Abbreviations: ds, distal swelling; pd, penial duct.