|
|
The Ischnochitonidae is a very large family of small
to medium sized chitons occurring in tropical, temperate and polar seas.
They live from the littoral zone down to at least 100 m. The family is
particularly well represented in southern Australia; some species, such
as Ischnochiton australis, are among the most common animals on
intertidal rocky shores there.
The feeding preferences of the Ischnochitonidae are
varied. Kangas & Shephed (1984) found herbivorous, omnivorous and
carnivorous species in South Australia. Reproductive strategies are also
varied. Most species cast eggs and sperm into the sea, but brooding of
young in the pallial groove has been reported for several species (Penprase,
1981).
Family References
-
Iredale, T. & Basset Hull, A.F. 1927 A
Monograph of the Australian Loricates. Royal Zoological Society
of New South Wales, Sydney. 168 Pp. (This is a consolidated and
repaginated version of the same material that had been published in
sections in The Australian Zoologist over the years 1923-1927).
-
Kaas, P. & Van Belle, R. 1985. Monograph
of Living Chitons Volume 2 Suborder Ischnochitonina E.J.
Brill/Dr. W. Backhuys Leiden.
-
Gowlett-Holmes, K. 1998. Family
Ischnochitonidae. Pp. 180-182 in Beesley, P.L., Ross, G.J.B. &
Wells, A. (eds) Mollusca: The Southern Synthesis. Fauna of
Australia. Vol. 5. CSIRO Publishing: Melbourne. Part B. viii
565-1234 pp.
-
Gowlett-Holmes, K. 2001. Ischnochitonidae. Pp
57-70 in Wells, A. & Houston, W.W.K. (eds) Zoological
catalogue of Australia. Vol. 17.2 Mollusca: Aplacophora,
Polyplacophora, Scaphopoda, Cephalopoda. Melbourne: CSIRO
Publishing, Australia.
Coverage
All the species of this family known to occur in NSW
are treated in detail here, with the exception of the following three
problematic species.
Ischnochiton carinulatus (Reeve, 1847)
This was previously known as Ischnochiton
tateanus Bednall, 1897, and recorded from SA and Vic. It was
reported from southern NSW in 1927 as dredged in Disaster Bay and
Twofold Bay (Iredale & Hull, 1927, p. 19), but has never been
reported from NSW subsequently.
Ischnochiton purus Sykes, 1896
This is a small, rare subtidal species known
from SA and Vic. Iredale & Hull (1927, p. 39) gave the
distribution as southern NSW and Victoria but did not give specific
localities. The Australian Museum does not hold any specimens from
NSW and there are no literature references after 1927 to its
occurrence in NSW.
Ischnochiton cariosus Carpenter, 1879
The Australian Museum holds specimens collected
by SCUBA from Twofold Bay, NSW, in 1985, which extend the recognised
range of WA to Vic into southern NSW.
Identification Notes
The following tabulation shows the girdle scale
characters of the subgenera of Ischnochiton.
Ischnochiton (Ischnochiton)
Distinguishing characters: Girdle scales striate
NSW species:
Small scales Ischnochiton examinandus
Medium size scales Ischnochiton elongatus
Large scales Ischnochiton versicolor
Ischnochiton (Haploplax)
Distinguishing character: Girdle scales smooth,
Valve surface smooth.
NSW species:
Ischnochiton lentininosus
Ischnochiton smaragdinus
Ischnochiton (Ischnoradsia)
Distinguishing characters: Shell very large size,
constant dark color, girdle scales smooth, pointed at sides
NSW species:
Ischnochiton australis
Ischnochiton (Heterozona)
Distinguishing characters: Girdle scales vary in
size from large near the valves to small at outer edge of girdle
NSW species:
Ischnochiton fruticosus
Subterenochiton
Distinguishing character: Shell very small, Valve
sculpture shows lines of pustules
NSW species:
Subterenochiton gabrieli
|