Permian 290248 mya

The world of the Permian saw a steady decline in the intensely hyperoxic and tropical global climate of the Carboniferous. Even though the opening of this period was similar to that of the Carboniferous world, its close would be marked by the most traumatic cataclysm earth ever experienced (Kaiho et al., 2001). Like the Carboniferous, relatively few deposits provide significant glimpses into the insect fauna at this time. In fact, there are five principal deposits -two from the Early Permian, three from the Late Permian -

which have generally shaped our knowledge of Permian insects (discussed later). Other, lesser-studied deposits are from Colorado (Lesquereux, 1882; Scudder, 1890b), Texas (Carpenter, 1962), New Mexico (Kukalova-Peck and Peck, 1976), Brazil (Rosler et al., 1981; Pinto and Pinto, 1981), Argentina (Pinto and Mendes, 2002), France (Gand et al., 1997; Nel et al., 1999; Bethoux et al., 2001, 2002a,b, 2003), Rhodesia (Zeuner, 1955), Germany (Hörnschemeyer, 1999), Democratic Republic of the Congo (Pruvost, 1934), South Africa (Pinto and Ornellas, 1978; Geertsema and van der

2.44. Continental configurations and climate during the Late Carboniferous. All paleomaps based on Scotese's Paleomap website and from Willis and McElwain (2002).

2.45. Frank Carpenter at the famous Permian insect locality in Elmo, Kansas in the late 1920s. First studied by R. J. Tillyard, the Permian insects at Elmo (e.g., Figures 6.9, 6.25) were then studied by Carpenter for nearly 60 years. Photo: Liz Brozius, Kansas Geological Survey.

2.46. The hills at Elmo, Kansas today, where there outcrops the world's most prolific and diverse deposits of Permian insects. These are found in the Early Permian Wellington Formation, which has yielded insects also at Midco, Oklahoma. The largest known insect, Meganeuropsis permianum, is from the Wellington Formation. Photo: M. S. Engel.

2.45. Frank Carpenter at the famous Permian insect locality in Elmo, Kansas in the late 1920s. First studied by R. J. Tillyard, the Permian insects at Elmo (e.g., Figures 6.9, 6.25) were then studied by Carpenter for nearly 60 years. Photo: Liz Brozius, Kansas Geological Survey.

Heever, 1996), Kazakhstan (Vilesov and Novokshonov, 1994), Mongolia (Gorokhov, 1992), China (Lin, 1978; Lin and Han, 1985; Lin and Liang, 1988), and India (Srivastava, 1988).

Elmo, Kansas, and Midco, Oklahoma. Perhaps the most productive deposits in the world with Permian insects are those from the Wellington Formation of central Kansas (Figures 2.45, 2.46) and northeastern Oklahoma in the United States. These small lenses of fossils are approximately 267 myo (Artinskian) and occur in at least three limestone layers clustered at the bottom of the series. The stratigraphy is poorly worked out, with the most significant reports being those of Dunbar (1924), Raasch (1940), Tasch and Zimmerman (1959, 1962), and Tasch (1962, 1963). The lenses with insects originated as lakes - some freshwater - while others were apparently playas. The entire region was coastal, with nearby bodies of water that freshened as the sea regressed. The insect fauna was extensively studied in the past by individuals such as Sellards, Tillyard, and most impressively by Carpenter. To date over 15,500 specimens have been amassed from Elmo, representing 150 species from 17 orders (Engel, 1998c; Beckemeyer, 2000) (no tally has yet been made for the sites in Oklahoma). Although work on these fossils essentially ceased in 1998, a great deal remains to be completed both in the basic descriptive and taxonomic work as well as more synthetic studies of the evolutionary-phylogenetic implications of these taxa. The largest insect ever, Meganeuropsis permi-ana (M. americana is a junior synonym), is known from the Wellington Formation.

Oboro, Czech Republic. The lacustrine mudstone of the Boskovice Furrow in Moravia, Czech Republic, is of either Early Artinskian (Kukalova-Peck and Willmann, 1990) or Sakmarian (Zajic, 2000) in age. Regardless, a diversity of Lower Permian insects has been recovered and described from these deposits (e.g., Kukalova, 1955, 1960, 1963, 1964,

2.46. The hills at Elmo, Kansas today, where there outcrops the world's most prolific and diverse deposits of Permian insects. These are found in the Early Permian Wellington Formation, which has yielded insects also at Midco, Oklahoma. The largest known insect, Meganeuropsis permianum, is from the Wellington Formation. Photo: M. S. Engel.

1965, 1969c; Kukalova-Peck, 1975; Kukalova-Peck and Willmann, 1990; Carpenter and Kukalova, 1964), representing one of the most important Paleozoic insect localities in the world.

European Russia. Historically, the most extensively studied Permian locality is that of Tshekarda. The mudstones of the Koshelevka Formation were originally believed to be of earliest Permian (even latest Carboniferous) age, but have subsequently proven to derive from the later half of the Permian (Kungurian) (Ponomaryova et al., 1998). The deposits are exposed along the Sylva River in the Urals of Russia. Soyana is another, albeit slightly younger (Kazanian), significant Upper Permian locality. Along the Soyana River in the northern Urals of Russia (Arkhangelsk region), the Iva-Gora limestones continue to yield new specimens.

Belmont, Australia. The fine-grained chert of the Newcastle Coal Measures near Belmont, Australia, are of Tatarian age (Kristensen and Wilson, 1986) and contain a limited, seemingly biased, group of insects heavy in primitive parane-opterans and mecopterids. The fauna has been most recently studied by Knight (1950), Evans (1947, 1958) and Riek (1953, 1968, 1971).

Natal, South Africa. In the Beaufort Series in southern Africa, principally near Natal, South Africa, along the Moori River, insects representing the Upper Permian (Tatarian) can be found in relative abundance. The stratigraphy of the Beaufort Series has been examined by Botha and Linstrom (1978). The fauna has not been extensively studied but material has been described by Riek (1973), van Dijk (1997), Geertsema and van Dijk (1999), and van Dijk and Geertsema (1999).

The Paleozoic was terminated by an event where approximately 85% of marine taxa and 70% of terrestrial taxa became extinct (Valentine et al., 1978; Raup, 1979; Sepkoski, 1989; Erwin, 1993, 1994; Bentop and Tooitchett, 2003). The End Permian Event (EPE) is shrouded in mystery, much of the geological evidence for its cause obscured by the action of tectonics and time. Various theories account for the cause and the possible duration of the change, and it is likely that a combination of factors contributed to the extinctions. The EPE appears to have been confined to a period of approximately one million years (Bowring et al., 1998) - most taxonomic extinctions occurred relatively quickly in both the marine and terrestrial environments (e.g., Erwin, 1993; Retallack, 1995; Eshet et al., 1995; Rampino and Adler, 1998; Jin et al., 2000). During the EPE there was significant geological turmoil: Extensive volcanism and basalt flows occurred, the supercontinent of Pangaea formed around 300 mya, much of the continental shelf was lost, and the oceans began to regress (Holser and Magaritz, 1987; Wignall and Hallam, 1992, 1993, 1996; Wignall and Twitchett, 1996; Wignall et al., 1996). Like the more famous Cretaceous-Tertiary boundary impact, the EPE has also been attributed at times to experiencing a massive extraterrestrial impact, as now seems to be the case for most major extinction events (e.g., Becker et al., 2001; Kaiho et al., 2001). Whatever its source, the Paleozoic-Mesozoic transition marks the single most pervasive extinction event for life, and for the insects as well. While insects suffered little when tetrapods met their demise 65 million years ago at the end of the Cretaceous, the Permian-Triassic event dealt everything a heavy blow.

Although a seemingly abrupt episode of upheaval on the planet, some dramatic changes were certainly more progressive and were rewriting the composition of our planet regardless of these catastrophes. Atmospheric concentrations changed significantly during this period, with oxygen levels dropping dramatically and continuously across the Permian from their previous hyperoxic state in the Carboniferous. Had no "event," whatever it may have been, taken place at the end of the Permian, significant changes in the flora and fauna must have already been in the process of shaping. For example, the giant insects present in early periods could not have continued to diffuse oxygen to their body core and would likely have become extinct naturally. Despite the End Permian Event and the devastating toll it weighed upon life, greater things were yet to come.

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