Taxonomy and anatomy of Amphiboloidea (Gastropoda: Heterobranchia: Archaeopulmonata)
Author
Golding, Rosemary E.
Author
Ponder, Winston F.
Author
Byrne, Maria
text
Zootaxa
2007
1476
1
50
journal article
10.5281/zenodo.176773
1a670eb6-5f50-42d6-ace0-3e52fd4f4c17
1175-5326
176773
Genus
Amphibola
Schumacher, 1817
Amphibola
Schumacher, 1817
: 190
.
Type
species
Amphibola australis
Schumacher, 1817
(subjective synonym of
A. crenata
), by original designation.
Ampullacera
Quoy & Gaimard, 1832
: 196
.
Type
species
Bulimus avellana
Bruguière, 1789
(as
Ampullacera avellana
) by subsequent designation (
Gray 1840
) (subjective synonym of
A. crenata
).
Thallicera
Swainson, 1840
: 339
.
Type
species
Bulimus avellana
Bruguière, 1789
(as
Thallicera avellana
) (subjective synonym of
A. crenata
) by monotypic designation.
Ampullarina
Sowerby, 1842
: 64
.
Type
species
Bulimus avellana
Bruguière, 1789
(as
Ampullarina avellana
) (subjective synonym of
A. crenata
) by monotypic designation.
Diagnosis:
Shell diameter to
35 mm
, thick, grey to light brown, exterior roughened, shoulder on last whorl square, spire short; umbilicus wide with fold or plait adjacent to aperture in some specimens, columellar callus sometimes present; sinus notch raised and square. Operculum thick, brownish-red, entirely corneous, elongate, with paucispiral nucleus at base of columellar edge; inner surface of operculum with slightly raised, incomplete spiral around nucleus. Head and foot dark grey to black in formalin-preserved specimens. Opposed ciliary tracts running full length of mantle cavity. Hypobranchial gland anterior to kidney approximately 1/4 mantle length, dark red, raised to form rounded dome, with numerous black-pigmented ducts leading to embedded glandular cells. Radula with central tooth, inner and outer lateral teeth, approximately 30 marginal teeth on each side of radula; central tooth of radula with hexagonal, flattened mesocone; inner lateral teeth narrow, bicuspid; outer lateral teeth with three cusps, marginal teeth elongate, narrow, curved. Central nervous system euthyneurous, with cerebral and pleural ganglia connected by distinct commissure; subcerebral and parapedal commissures present; visceral loop long, with accessory ganglion present between left parietal and visceral ganglia. Seminal vesicle occupying upper hermaphrodite duct, highly folded and coiled; seminal receptacle unpigmented. Spermoviduct folded, with hairpin-bend distally. Spermovipositor cylindrical; spermoviduct continues through spermovipositor forming narrow duct opening beneath shallow hood at tip; second duct opens near end of spermovipositor but is blind ending internally; spermovipositor lacking microsculpture. Thin walled spermovipositor sheath enclosing spermovipositor, lacking pouches. Prostatic gland proximally lined with epithelium comprising short secretory cells. Egg mass approximately
3 cm
diameter, semi-circular or collar shaped, elliptical in cross-section.
Remarks:
A relatively large amount of descriptive information has been published on the
type
species,
A. crenata
(e.g.
Farnie 1919
). Other taxa attributed to
Amphibola
are of uncertain affinity (see
Incertae sedis
section). The generic diagnosis was thus formulated for
A. crenata
alone.
Amphibola
is distinguished from the other amphibolids by a larger shell with a prominent square shoulder and raised, indented sinus. The operculum is unique within the
Amphibolidae
in its elongate shape and basal, rather than eccentric, nucleus. Other characteristic features include the highly folded spermoviduct and cylindrical spermovipositor containing a second, blind-ending duct of unknown function.