. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 14 ANNALS OF THE SOUTH AFRICAN MUSEUM time range from Cambrian to Jurassic (Hantzschel 1975: W84), whereas Ophio- morpha (Lower Permian-Recent) is typically associated with strata younger than the Sardinia Bay Formation (Hantzschel 1975: W85). Ophiomorpha-like structures in modern sediments are produced by callianassid decapods (Weimer & Hoyt 1964). THALASSINOIDES SP. Description Smooth-walled sand-filled sub-horizontal to inclined burrows, with a lining of dark pyritic sand and circular to flatt
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 14 ANNALS OF THE SOUTH AFRICAN MUSEUM time range from Cambrian to Jurassic (Hantzschel 1975: W84), whereas Ophio- morpha (Lower Permian-Recent) is typically associated with strata younger than the Sardinia Bay Formation (Hantzschel 1975: W85). Ophiomorpha-like structures in modern sediments are produced by callianassid decapods (Weimer & Hoyt 1964). THALASSINOIDES SP. Description Smooth-walled sand-filled sub-horizontal to inclined burrows, with a lining of dark pyritic sand and circular to flattened-oval in cross-section (Fig. 4), occur in close stratigraphic proximity to beds permeated by large vertical Ophiomorpha- type burrows. These burrows often show repeated branching (Fig. 5). Burrow diameters range from 2 to 10 cm and individual shaft sections are up to 50 cm long. Inclined shafts may run parallel to foreset surfaces in the cross-bedded sandstone. Interpretation The sub-horizontal branching burrow systems described above are closely similar to Thalassinoides (Triassic-Recent), which are generally considered to be the dwelling burrows of callianassid decapods (Hantzschel 1975: W117) or crabs (Radwanski 1977: 233-235).. Fig. 5. Partly weathered burrows showing initial erosion of burrow lining and eventual excava- tion of fill and lining. Basal surface of a sandstone. Note the branching burrow (arrowed) which resembles Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original South African Museum. Cape Town : The Museum
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
