FAMILY NAUTILIDAE. The pearly or chambered nautilus belong to the Class Cephalopoda, a highly developed group of molluscs which include the squids, cuttlefishes and octopuses.
1 & 2. Nautilus pompilius LINNAEUS. Often washed ashore after storms. Juvenile shells occasionally have an open umbilicus. Examination of several specimens similar to fig. 2 indicates that this is a form of pompilius lacking the usual calloused shield over the umbilicus. The opening is deep, narrow and not shouldered about the periphery.
3. Nautilus macromphalus SOWERBY. Similar to previous figure in all respects except that the umbilicus is widely open and the periphery of the depression is roundly but distinctly shouldered. Moderately rare.
4. Nautilus scrobiculatus LIGHTFOOT. Moderately rare. Figured specimen from Admiralty Group. Recorded also from Samarai.
FAMILY ARGONAUTIDAE. Also placed in the Class Cephalopoda, the paper nautilus is not a true shell or external skeletal structure but a fragile container developed by the female of the species for depositing and protecting her eggs.
5. Argonauta nodosa LIGHTFOOT. Found on beaches after storms. Similar to A.argo but with wider and more flaring aperture. Common.
6. Argonauta argo LINNAEUS. Uncommon in P.N.G. but distributed world-wide and common in some areas. Figured specimen is a small shell and this species approximates the size of A.nodosa, averaging 220mm. Similar to nodosa but has a narrower aperture and lacks the nodules on the bifurcating ribs of that species.
7. Argonauta boettgeri MALTZAN. A scarce species ranging from north Queensland to Japan. Similar to A.hians, but has stronger tubercles on the double keel and a much smaller aperture.
8. Argonauta hians LIGHTFOOT. Uncommon but more often found than previous species which it resembles.
Information reproduced from The Shells of Papua New Guinea, Adelaide: Crawford House.|
© Copyright by Alan Hinton, 1974. HTML version produced with permission and
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