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Phrantela umbilicata Ponder & Clark, 1993

Diagnostic features

Apart from the trochiform shell, this species also differs in having a different operculum from any seen in the Beddomeia-Phrantela complex, the nucleus being more nearly central and there being a low spiral ridge in the middle of the opercular whorls. . The two-whorled protoconch is also unusual in having very well-developed pitting. The rectum is extremely wide and the ctenidium very short and confined to the anterior part of the pallial cavity, being connected to the pericardium by a very long efferent vessel. Phrantela bobbrowni is intermediate in shell characters between P. umbilicata and other members of the genus but has an operculum and protoconch like those of the other species of Phrantela.

Classification

Phrantela umbilicata Ponder & Clark, 1993

Class Gastropoda

Subclass Caenogastropoda

Order Littorinimorpha 

Superfamily Truncatelloidea

Family Tateidae

Genus Phrantela  Iredale, 1943

Original name: Phrantela umbilicata Ponder & Clark, 1993 in Ponder, W. F., Clark, G. A., Miller, A. C and 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 creek, immediately upstream from Kutikina Cave, Franklin River, Tasmania.

Biology and ecology

This species is known only from one locality, no other similar material being found elsewhere. It is rather common along the stream edges, living under lichens overhanging the stream in litter and silt. Egg capsules unknown but probably like those of another species of Phrantela; small, with single embryo, and covered in coarse sand grains. Development direct.

Distribution

Small creek, just upstream from Kutikina Cave, Franklin River, W Tasmania.

Notes

This very distinctive species is included in Phrantela because it cannot be distinguished anatomically, although this may be because the key anatomical characters of Phrantela are plesiomorphic.

Further reading

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.