Pseudotricula elongata, Ponder & Clark & Eberhard & Studdert, 2005

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 : 26-27

Pseudotricula elongata n. sp.

Figure 11A–C .

Type material

Holotype: AMS C.166854, Bauhaus, Persephone Pot, stn PB17–8R, 3, JAN, 1990.

Paratypes: AMS C.201809, same location, middle and upper streamway, stn PB17­ 2a.2, 27, March 94 (3 dry) ; AMS C.203713, same location, stn 9, 23, DEC, 1991 (1 dry, 1 wet) .

Etymology Elongatus Latin, prolonged; refers to the elongate shell.

Description

Shell ( Fig. 11A–C ). Length up to 2.8 mm; elongate­conic broadly conical (SW/SL 0.45–0.56, mean 0.49, n = 3);spire tall, straight in outline; last whorl evenly rounded, or angular to subangular in middle of whorl; suture grooved/channelled or with very narrow shoulder above or below. Protoconch microsculpture unknown. Teleoconch up to 4.4 whorls in adult; aperture oval to pear­shaped; small, much shorter than spire (AL/SL 0.37– 0.44, mean 0.40, n = 3); outer lip orthocline, straight, with narrow reflection and thickened; notch present in posterior corner of aperture; inner lip thin to moderately thickened and narrow to medium width, in partial contact or narrowly separated from parietal wall.

Dimensions. See Table 5.

Distribution and habitat

Known only from Persephone Pot, Bauhaus, where it lives in a narrow (about 0.5m wide), slow flowing (estimated about 1L/s) stream. The substrate is composed of cobbles, gravel and silt.

Remarks

Pseudotricula elongata has a very distinctive, elongate shell shape and is known only from a few specimens. It is only known from Persephone Pot, where it is found living with several other species ( Table 15). It is readily distinguished from all of the other species found in the caves by its large, elongate shell and distinctly sinuate outer lip.

Figures

FIGURE 11. Shells of Pseudotricula species. A ­ C, Pseudotricula elongata, Persephone Pot, A, holotype, C.166854; B,C, paratypes, B, C.203713, C, C.201809; D–F, Pseudotricula arthurclarkei, C.203671, paratypes, Quetzalcoatl Conduit. Scales: A ­ C, 500 m; D–F, 1 mm.