Pigmentation bands on an early Devonian nautiloid

1 Pages·1994·0.84 MB·

by  Alex G Cook

40 MEMOIRSOFTHEQUEENSLANDMUSEUM
PIGMENTATIONBANDSONANEARLYDEVONIAN tion,inthiscaseappearstohavebeenfacilitatedbytheearly
NAUTILOID. Memoirsofthe QueenslandMuseum 37(1): encrustation of the stromatoporoid, providing protection
40. 1994;- A specimen of an ?orthoceratid nautiloid was against crushing, and a significant buffer to destructive
collected in 1990fromtheMartinsWellLimestone, Broken diagenericprocesses.
RiverProvince, north Queensland (QM Locality 549). The
MartinsWellLimestonememberoftheShieldCreekForma- LiteratureCited
tioncontainsadiversefaunaindicativeofanEarlyDevonian Foerste,A.F. 1930.Thecolorpatternsoffossilcephalopods
(Lochkovian- Pragian)age (Jell etal., 1993).The specimen and brachiopods, with notes on gasteropods and
(QMF32208)isa92mmlongfragmentofanorthoconicshell pelecypods.ContributionsfromtheMuseumofPaleon-
(Fig. 1) and isexposedonlyon the lateral parts ofthe shell tology,UniversityofMichigan3(6): 109-150.
with the dorsum and venter apparently obscured. The shell Jell, J. S., Simpson, A., Mawson, R. & Talent, J. 1993.
had been encrusted by an actinostromatid stromatoporoid Biostratigraphy. Pp. 239-245. In Withnall, L W. &
skeleton, and the preserved shell surface represents this Lang, S. C. (eds), 'Geology of the Broken River
encnistedsurface. Province, north Queensland'. Queensland Geology 4.
Upontheoutershellsurfacearepreservedthin,lightgrey (DepartmentofMineralsandEnergy: Brisbane).
sinuous bands 1.8-2.0mm thick, separated by thicker dark Teichert.C. 1964,Morphologyofhardparts.Pp. K13-53. In
grey bands3.3-4.4mm thick.Thepattern is restricted to the Moore, R. C. (ed.), 'Treatise on Invertebrate
exteriorshell surface, andthepigmentationdoes notappear Palaeontology'. Part K. Mollusca 3. (Geological
inlongitudinalsectionassuturesorseptalremnants.Ribbing Society of America and University of Kansas Press:
isdiscountedgiventhatalongitudinalsectionrevealedathin Lawrence,Kansas)
smooth, un-ribbed shell.Thepatternis thusconsidered as a Alex G. Cook Queensland Museum, PO Box. 3300, South
relictsurfacepigmentation. Brisbane, Queensland410V.Australia; JlNovember1994.
Preservation of pigmentation patterns on Palaeozoic
cephalopodsisrare(Foerste,1930;Teichert,1964).Preserva-
FIG 1 QMF32208,?orthoceratidnautiloidshowingpigmentationpatterns,x