P. daveyensis tristisis distinguished from the subspecies P. daveyensis daveysensis by its slightly smaller shell, the capsule and albumen glands being about equal in length instead of the capsule gland being longer, and the proximal U of the oviduct is very small and compact, not prominent and widely open. This population contains two shell forms, broad and narrow, that show some intergradation. These forms show no consistent anatomy differences. Phrantela daveyensis (s.1.) is also similar to P. kutikina and, to a lesser extent, P. warwicki, in shell characters. It differs from P. kutikina in being a little larger, in having more ctenidial filaments (20-26 compared with 16-17), the distal end of the penis narrowly tapering instead of being expanded, the bursa copulatrix extending to just behind the posterior pallial wall, not in front of it, and the female genital opening being a longer slit.
Phrantela daveyensis tristis Ponder & Clark, 1993
Class Gastropoda
Infraclass Caenogastropoda
Order Littorinida
Suborder Rissoidina
Superfamily Truncatelloidea
Family Tateidae
Original name: Phrantela daveyensis tristis Ponder & Clark, 1993. In Ponder, W. F., Clark, G. A., Miller, A. C & Toluzzi, A. (1993). On a major radiation of freshwater snails in Tasmania and eastern Victoria - a preliminary overview of the Beddomeia group (Mollusca: Gastropoda: Hydrobiidae). Invertebrate Taxonomy, 7: 501-750.
Type locality: Small tributary of Dismal Creek, tributary of Hardwood River, Tasmania.
This taxon was originally found in a small swampy stream living on debris mainly along the edges. Egg capsules unknown but probably like those of an unnamed species of Phrantela; small, with single embryo, and covered in coarse sand grains. Development is direct.
A species of Austropyrgus and two other species of Phrantela also occurred together with the orginal material of P. daveyensis tristis.
Originally described from a small tributary of Dismal Creek, tributary of Hardwood River, southwest Tasmania, specimens identified as this species have also been found in a number of locations in SW Tasmania.
Ponder, W. F., Clark, G. A., Miller, A. C. & Toluzzi, A. (1993). On a major radiation of freshwater snails in Tasmania and eastern Victoria: a preliminary overview of the Beddomeia group (Mollusca: Gastropoda: Hydrobiidae). Invertebrate Taxonomy 7: 501-750.
