Applications

GONIAT has already been used widely for the creation of comprehensive catalogues. The main data source of the work on Devonian ammonoids (Korn and Klug, 2002) was based on GONIAT. The Carboniferous/Permian volume of the Treatise on Invertebrate Paleontology, the revision of part L, will be partly connected with GONIAT.

Critical intervals in the history of ammonoids can be easily described by using GONIAT. The quantitative aspect of ammonoid evolution during the Pennsylvanian (Upper Carboniferous) may serve as an example (Kullmann, 2002). On the family level, high turnover rates (Fig. 4.2) are evident at three turning points (Table 4.1): (1) at the Yeadonian/Langsettian boundary [YLB, between Namurian/Westphalian (Eurasia) or Halian-Bloydian (America)], four families became extinct and five appeared; (2) around the Moscovian/Kasimovian boundary [MKB, Eurasia or Desmoinesian/ Missourian (America)], two or three families became extinct, three families appeared, and two or three families started to proliferate; and (3) at the Carboniferous-Permian boundary (CPB), five families became extinct and two appeared. The unusually high changeover rate of genera corroborates this impression: in the Yeadonian, 57% of the genera became extinct (16 out of 28), in the Kasimovian (Missourian), 42.3% (11 out of 26), and in the upper Gzhelian (late Virgilian), 46.5% (13 out of 28); in cases (1) and (3), the rate of surviving genera was rather low.

The qualitative analysis of the critical intervals shows a considerable change in the main characters of ornamentation and suture line, whereas the conch form does not vary fundamentally. Below the YLB, half of the species are strongly ornamented. In the early Moscovian, provincialism expanded; the neritic, strongly ornamented gas-trioceratids were replaced by the smooth-shelled pelagic glaphyritids.

Approximately 90% of the existing species became extinct at the MKB and were replaced by goniatitids and prolecanitids showing a considerable increase in suture elements, frequently with subdivided and partly digitate sutures. At the CPB, the number of simple goniatites with a low number of lobes was strongly reduced and replaced by multilobate goniatitids with enormously complicated sutures. In general, the fluctuations of the ammonoid faunas during the critical intervals showed comparable patterns: a stepwise decline in diversity, a low point, an initiation point for new characters, and later stepwise increased evolutionary diversification.

Fig. 4.2 Chart showing the range of Late Carboniferous and Early Permian ammonoid families. Abbreviations: Y, Yeadonian substage; Langs., Langstettian substage (=West-phalian B); Du., Duckmantian substage (=Westphalian B); Bol., Bolsovian substage (=Westphalian C); Kasim, Kasimovian stage; Miss., Missourian stage.

Fig. 4.2 Chart showing the range of Late Carboniferous and Early Permian ammonoid families. Abbreviations: Y, Yeadonian substage; Langs., Langstettian substage (=West-phalian B); Du., Duckmantian substage (=Westphalian B); Bol., Bolsovian substage (=Westphalian C); Kasim, Kasimovian stage; Miss., Missourian stage.

Table 4.1. Global time planes as used in GONIAT version 3.0 (left of dash: below boundary; right of dash: above boundary).

288 Asselian-Sakmarian

292 CPB,Carboniferous-Permian Boundary,base of Permian

295 Lower Gzhelian-upper Gzhelian

297 Kasimovian-Gzhelian, Missourian-Virgilian

301 Moscovian-Kasimovian, Desmoinesian-Missourian

306 Atokan-Demoinesian (Kashirian-Podolskian)

308 Bolsovian-Westphalian D

311 Morrowan-Atokan, Duckmantian-Bolsovian

313,5 Langsettian-Duckmantian

314,5 Bashkirian-Moscovian

316,5 Namurian-Westphalian, Yeadonian-Langsettian, Halian-Bloydian

317,5 Marsdenian-Yeadonian

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