Permo-Triassic Tetrapods
The following diagram is from Fig. 2. of R.T. Bakker, 1977 "Tetrapod Mass Extinctions - A model of the regulation of speciation rates and immigration by cycles of topographic diversity" in A. Hallam, ed. Patterns of Evolution as illustrated by the Fossil Record, Elsevier Scientific Publishing Company, Amsterdam, Oxford, New York, pp.439-68
Although subsequent research has modified some of the family rankings and stratigraphic correlations, the basic pattern remains.
Diversity of non-marine tetrapods, early Late Permian to Early Jurassic. Each bar represents one family. Narrow extensions of bars indicate that the family is present but very rare. Families known from only one formation are omitted. Roman numerals at top show the successive "dynasties". Biomass D has been calculated for each faunal level from the formation with the largest number of identifiable specimens. The faunal levels are represented by the following formations (the first named formation supplies the data for D, except for no.8, where two have been combined because of small sample size):
1, Tap Zone, Russian Zone II; 2, Ruhuhu, low Kistecephalus Zone; 3, upper Kistecephalus Zone, Madumabisa Mudatone; 4, low and middle Daptocephalus Zone, Kawinga; 5, upper Daptocephalus Zone; 6, Lystrosaurus Zone (South Africa); 7, Cynognathus Zone, ?Ur-Ma-Ying; 8, Omingonde Mudatone, Russian Zone VI; 9, Manda; 10, Santa Maria; 11, lschigualasto, lower Red Beds (South Africa); 12, Lower Chinle, lower Los Colorados, Wolfville; 13, upper Los Colorados, Stuben Sandstone; 14, Lufeng Beds, Knollenmergi, upper Red Beds (South Africa); 15, Forest Sandstone, Cave Sandstone, Portland Arkose. The South African and Russian "zones" correspond in rank to formation or series.
Family abbreviations:
Large Herbivores: A = titanosuchids; B = struthiocephalids; C = tapinocephalids; D = moschopids; E = styracocephalids; F = pareiasaurids; G = endothiodontids; H = oudenodontids; I = aulacephalodontids; J = whaitsiids; K = daptocephalids; L = lystrosaurids; M = diademodontids; N = kannemeyeriids; 0 = stahleckerilds; P = shansiodontids; Q = rhynchosaurids; R = traversodontids; S = aetosaurids; T = melanorosaurids; U = plateosaurids.
Large Carnivores: A = anteosaurids; B = hipposaurids; C = gorgonopsids; D = lycosuchids; E = pristerognathids; F = moschorhinida; G = proterosuchids; H = erythrosuchids and rauisuchids; I = cynognathids; J = herrerasaurids K chiniquodontids; L = ornithosuchids; M = procompsognathids (including halticosaurs and dilophosaurs).
Small Terrestrial: A = dissorophids; B = dikopsids; C = scaloposaurids; D = emydopsids; E = nycteroleterids; F = kingoriids; G = procolophonids; H = kistecephalids; I = procynosuchids; J = galesaurids; K = prolacertids; L = trirachodontids; M = bauriids; N = sphenodontids; O = gracilosuchids; P = pedeticosaurids; Q = heterodontosaurids; R anchisaurids; S = tritylodontids; T = fabrosaurids; U = ictidosaurids; V = icarosaurids; W = khuneotheriids; X = morganucondontids.
Fresh-Water Aquatics: A = archegosaurids; B = rhinesuchids; C = brachyopoids; D = benthosuchids; E = uranocentrodontids; F = rhytideosteids; G = sclerothoracids; H = lydekkerinids; I = trematosaurids; J = capitosaurids; K = metoposaurids; L = phtyosaurs; M = cerritosaurids.
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page uploaded 3 April 2001. Last modified 12 August 2005
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