Tethyan Region Research Articles

Early Cretaceous (Valanginian) sea lilies (Echinodermata, Crinoidea) from Poland

Valanginian strata in central epicratonic Poland have recently yielded crinoids, not previously recorded from the area. The fauna comprises isocrinids (Balanocrinus subteres, B. gillieroni, “Isocrinus?” lissajouxi), millericrinids (Apiocrinites sp.) and comatulids (Comatulida indet.). For comparison, a few samples of isocrinids from Valanginian strata of Hungary (Tethyan province) were also analysed. The isocrinids, cyrtocrinids and roveacrinids (sensu Rasmussen 1978 inclusive of Saccocoma sp.) were already known from the Valanginian of the southernmost Tethyan regions of Poland (Pieniny Klippen Belt and Tatra Mountains). The current study demonstrates their occurrence in central epicratonic Poland, and suggests that many Jurassic to Cretaceous stalked crinoid taxa (mainly isocrinids) predominated in the shallow-water settings of this area. Thus, the hypothesis of migration (at least from mid-Cretaceous onwards) to deep-water areas, as a response to an increase of the number of predators during the Mesozoic marine revolution, seems not to be universally applicable.

FIRST RECORD OF THE CO-OCCURRENCE OF WESTERN TETHYAN AND INDO-PACIFIC LARGER FORAMINIFERA IN THE BURDIGALIAN OF THE MEDITERRANEAN PROVINCE

A revision of (early) Burdigalian hyaline larger foraminifera based on the biometric study of miogypsinids, lepidocyclinids, and nummulitids from eastern Turkey provides new insights into their taxonomy and paleo-biogeography in the Tethys region. Data from the Adilcevaz Formation show a strong similarity to occurrences from Southeast Asia in that they include Cycloclypeus , Eulepidina , and “ribbed” Nephrolepidina , an assemblage not previously recorded from age-equivalent deposits in the circum-Mediterranean region. The association and the occurrences of these taxa in Lower Miocene deposits from the Indo–West Pacific areas have been widely reported. The species designation of Nephrolepidina and Eulepidina , in the absence of well-demonstrated comparable biometric and conflicting stratigraphic data from the Indo–West Pacific areas, is usually problematic. The Turkish taxa bear a close resemblance to N. sumatrensis and E. formosa , whilst Cycloclypeus is represented by C. eidae , which is widespread in the Indo-Pacific Early Miocene. These taxa are accompanied by Miolepidocyclina burdigalensis , a well-documented side branch of the main Miogypsina lineage in the circum-Mediterranean region; Miogypsina globulina , a worldwide tropical species common to both provinces; and Operculina complanata . Our data provide the first foraminiferal evidence from Turkey suggesting a main westward migration of several important groups from Southeast Asia to the eastern Mediterranean during the (early) Burdigalian. This faunal incursion is the most significant compared to other Late Oligocene–Early Miocene foraminiferal events in Turkey.

Ancient oceans and continental margins of the Alpine‐Mediterranean Tethys: deciphering clues from Mesozoic pelagic sediments and ophiolites

AbstractIn contrast to Northern Europe where, in the 19th Century, a coherent lithostratigraphy and biostratigraphy was established, many of the ‘odd rocks of mountain belts’ (as christened by Alfred G. Fischer) of the Alpine‐Mediterranean region defied an easy interpretation in terms of the simple English layer‐cake stratigraphy mapped by William Smith. However, as early as 1862, Eduard Suess recognized close affinities between Mesozoic faunas of the Alps and those of the Himalaya. Suess also described many such Alpine sedimentary rocks as pelagic (a term discussed by Antoine Lavoisier in the context of sea‐level change), and the results of theChallengerExpedition (1872 to 1876) convinced the Viennese school of geologists of their deep‐water nature. Based on the composition of Jurassic–Cretaceous faunas, Melchior Neumayr postulated the existence of an equatorial ocean, the ‘Central Mediterranean’ which extended from Central America through the Alpine belt to the Himalaya and beyond, an ocean which Suess subsequently named ‘Tethys’. The question of whether or not deep‐sea sediments could occur on land, as deliberately posed by Gustav Steinmann in 1925, became central to the long‐lasting controversy on the permanency of continents and ocean basins. Indeed, the occurrence of deep‐sea deposits in mountain belts required the disappearance of oceanic areas and a mobilist concept of orogeny that was subsequently applied to the Tethyan region by Emile Argand in the wake of the continental drift hypothesis of Alfred Wegener. Implicit in the views of Wegener and Argand is the concept of an oceanic crust fundamentally different from that of the continents. Although ophiolites had been recognized as a special group of rocks in the early 19th Century, Steinmann was the first to interpret the association of (serpentinized) peridotite, ‘diabase’ (dolerite–basalt) and radiolarite (Steinmann Trinity) in a geodynamic context and to consider it as characteristic of the deep ocean. The comparison of Alpine radiolarites with Recent radiolarian oozes deposited below the calcite compensation depth did not remain unchallenged, because of the local association of these siliceous rocks with coarse clastic deposits. However, after the advent of the turbidity‐current hypothesis, these detrital deposits were reinterpreted as submarine mass‐flow deposits. Consequently, such typical Tethyan facies asRosso Ammonitico,Maiolica/Bianconeand black shales, found in close stratigraphical association with the radiolarites, could be interpreted as deposited on deeply submerged continental and/or oceanic crust where they recorded faithfully a range of interdependent palaeoceanographic phenomena: changes in the relative proportion of siliceous, carbonate and organic‐walled biota, in carbonate saturation of sea water, in oceanic circulation and in the impact of orbital‐climatic cycles. The results of the Deep Sea Drilling Project, with its discovery of typical Jurassic and Cretaceous Tethyan facies in the Atlantic Ocean, dramatically confirmed the early interpretations of European geologists of the 19th and early 20th Centuries.

Late Permian (Lopingian) gastropods from the Qubuerga Formation at the Qubu section in the Mt. Everest (Qomolangma) Region, Southern Tibet (Xizang), China

Late Permian gastropod fauna in the Mt. Everest (Qomolangma) region, southern Tibet (Xizang), China is poorly known. This paper describes a small gastropod fauna collected by one of the authors (SSZ) from the upper part of the Qubuerga Formation at the Qubu section. The section is located at about 30 km north of Mt. Everest (Fig. 1). Although a limited number of specimens is available, the fauna is more diverse than all previously reported gastropod faunas (e.g., Yu, 1975) from southern Tibet. Description of the gastropod fauna in the Mt. Everest region adds significant data for understanding the distribution of gastropods during the Late Permian and the paleobiogeographic relationship between the Himalayan and Tethyan regions.

Revision of the north‐eastern Atlantic and Mediterranean species of the genera Herentia and Therenia (Bryozoa: Cheilostomata)

The cheilostome genera Herentia Gray and Therenia David and Pouyet, placed in the recently established family Escharinidae Tilbrook, were hitherto generally regarded as synonyms of Escharina Milne Edwards. Here we resurrect and define both genera, and revise their eastern Atlantic and Mediterranean species, which turn out to be species complexes. Besides presenting a re‐description of the genotype of Herentia, H. hyndmanni (Johnston) from the British Isles, new species from Madeira (Herentia andreasi n. sp.) and the Adriatic Sea (Herentia majae n. sp.) are introduced. The ancestrula of H. hyndmanni, a kenozooid with an almost completely calcified, gymnocystal frontal shield, is here documented for the first time. For Therenia it can be shown that the type species T. porosa (Smitt) from Florida differs from the eastern Atlantic and Mediterranean congeners, all of which were hitherto referred to as this species. Consequently, three new species (Therenia cryptooecium n. sp. from Ghana, Therenia peristomata n. sp. from Madeira, and Therenia rosei n. sp. from the Mediterranean Sea) are described. Both genera show a Paleogene origin and distribution in the Tethyan and Atlantic regions, and persist today in tropical to warm‐temperate zones of the Atlantic and Mediterranean Sea. Investigation of poorly studied, low‐ to mid‐latitude regions are likely to yield more new species of Herentia and Therenia.

OLIGOCENE ECHINOIDS FROM WADI AL GHADAF, JORDAN

A small collection of echinoids from the Eastern Desert of Jordan includes the species Clypeaster biarritzensis , Amphiope ? sp., Echinolampas cherichirensis , and Eupatagus meslei . This fauna closely resembles faunas of early Oligocene age from North Africa. The presence of the associated foraminifera Nummulites intermedius and N. fichteli dates the upper portion of the Wadi Shallala Formation exposed in the area of Wadi Al Ghadaf as early Oligocene (Rupelian), younger than the generally accepted middle (Bartonian) to late Eocene (Priabonian) age of this formation. The presence of rocks of this age in Jordan along what was probably the southern margin of the Tethyan Seaway is evidence that communication between the eastern and western provinces of the Western Tethys Region still existed in this area at this time.

A new species of Placidichthys (Halecomorphi: Ionoscopiformes) from the Lower Cretaceous Marizal Formation, northeastern Brazil, with a review of the biogeographical distribution of the Ophiopsidae

Abstract A new halecomorph fish is described from the Early Cretaceous Marizal Formation of Tucano Basin. This new material is identified as a new species of Placidichthys, P. tucanensis sp. nov. based on the absence of an anal fin, the lower number of flank scales in the caudal region, the slender shape of the body, and body proportions. Placidichthys tucanensis sp. nov. increases the distribution and diversity of ophiopsids in the western part of the Tethys Sea, being distributed along the epicontinental seas of Gondwana. Placidichthys is considered the sister-taxon of the exclusively Cretaceous taxa Teoichthys + Macrepistius from the western Tethys. These groups show a discernible geographical distribution pattern with Placidichthys known only from the Southern margin of the Tethys region (South America), whilst Teoichthys and Macrepistius are known only from North America and possibly Europe.

Debatable questions of Boreal Triassic stratigraphy: boundary between middle and upper series

Various opinions on the position of the Middle/Upper Triassic boundary have been concisely reviewed. The lower boundary of the Carnian Stage is accepted at the base of the Trachyceras aon Zone. The recentmost data on biostratigraphy of boundary beds of the Ladinian and Carnian Stages of the Southern Alps, Himalayas, British Columbia, northeastern Asia, Svalbard, and Arctic Canada have been considered and critically analyzed. Using sections of British Columbia with mixed Boreal and Tethyan fauna of Ammonoidea, we compared biostratigraphic schemes of the Middle/Upper Triassic boundary interval of the Boreal and Tethyan regions. On the basis of correlations and paleontological data, the lower boundary of the Carnian Stage in Northeastern Asia is suggested to be drawn at the base of the ammonoid “Protrachyceras” omkutchanicum Zone and its equivalents in other Boreal regions.

First hexactinellid sponge reported from the Upper Triassic Nayband formation of central Iran

Sponges, along with scleractinian corals, are among the main reef-building organisms in Triassic reefs. Hypercalcified groups, including the chambered sphinctozoans, and the unchambered inozoans, chaetetids, and spongiomorphids, represent the most abundant Triassic reef-building sponges. Earlier workers have described elements of the latter group as “hydrozoans.” Hexactinellid sponges, abundant in some Permian reefs (e.g., in Texas, Finks, 1960), are rarely known from similar Triassic deposits, in general (Tichy, 1975), and particularly from Upper Triassic stratigraphic units. Hexactinellid sponges have been sporadically reported from well-investigated Upper Triassic reefs in the western Tethyan region (e.g., Keupp et al., 1989). However, a variety of hexactinellid sponges have been reported from Upper Triassic deposits and reefal limestones of the northern and central Tethyan realm (Boiko, 1990; Wu, 1989; Wu and Xiao, 1989; Rigby et al., 1998).

Biogeographic responses to geodynamics: A key study all around the Oligo–Miocene Tethyan Seaway

Extensive terrestrial exchanges were initiated by the closure of the Tethyan Seaway during the Early Miocene. Proboscideans are among the most prominent African immigrants, which arrived in Eurasia about 19 Ma ago via the “ Gomphotherium Landbridge”. Several distinct waves of continental migrations, however, document that the formation of this landbridge was a multiphase process. Until the closure, a marine faunal exchange was enabled via the Mesopotamian Trough and the Zagros Basin, as reflected by contributions of Indonesian corals in the Iranian basins and by the occurrence of “western” gastropods in Pakistan and India. Nevertheless, the emergence of the landbridge was preceded in the marine biosphere by first biogeographic divergences on both sides of the seaway already during Oligocene times (e.g. within the tridacnines and strombids). Around the closure event, the breakdown of biogeographic relations was near-complete and the Proto-Mediterranean faunas bear little in common with those of the Indo-West Pacific Region (IWPR). Some of the discussed examples suggest that the Western Tethys Region (WTR) had acted as centre of origin and diversity during Oligocene and Early Miocene times. After the closure of the seaway, this centre had shifted to the southeast, heralding the enormous biodiversity of the modern IWPR. Some originally WTR elements managed to follow this shift and formed the Miocene stock for the modern IWPR faunas. In contrast, the marine fauna in the Mediterranean cul-de-sac suffered strong impoverishment due to the Miocene cooling, the Messinian Salinity Crisis and the late Pliocene and Pleistocene glacials – a fact which might explain the receptivity of the Mediterranean Sea for Lessepsian migrants. This synthesis tries to document the practical problem of recognising biogeographic patterns despite the heterochronous developments in different systematic groups, which, in addition, are often obscured by a stratigraphically incomplete and geographically patchy fossil record.

Conodont index fossil Hindeodus changxingensis Wang fingers greatest mass extinction event

The marine conodont fossil species, Hindeodus changxingensis Wang, that has a distinctive morphology, is restricted to a very narrow stratigraphic interval essentially from the Permian–Triassic extinction event through the internationally recognized boundary and into the very earliest Triassic. The species is geographically widespread in the Tethyan Region, from Italy to South China, and serves as a characteristic index fossil to reliably identify this short but critical interval that encompasses the greatest mass extinction of life on earth and the boundary between the Paleozoic and Mesozoic Eras.

Overview of tectonic settings related to the rifting and opening of Mesozoic ocean basins in the Eastern Tethys: Oman, Himalayas and Eastern Mediterranean regions

Abstract A combination of geophysical studies and deep-sea drilling have in the past suggested that orthogonally rifted margins fall into two end-members: volcanic-rifted margins (e.g. eastern Greenland) and non-volcanic rifted margins (e.g. Iberia–Newfoundland conjugate). This paper explores the rifted margins of the Eastern Tethys stretching from the Eastern Mediterranean, through Oman to the Himalayas. Rifting in these area was typically pulsed, extending over more than 50 Ma. The timing of final continental breakup ranged from Late Permian in the east, in Oman and the Himalayas, to latest Triassic–earliest Jurassic in many parts of the Eastern Mediterranean (e.g. Antalya in SW Turkey; Pindos in Greece). Rifting in the Himalayas and Oman gave rise to a proximal to a distal ramp geometry with scatted seamounts (continental fragments and atolls) located adjacent to the rifted margin. The Eastern Mediterranean was palaeogeographically varied, and was characterized by a number of mainly elongate continental fragments (tens to several hundreds of kilometres long by tens of kilometres wide). These microcontinents subdivided the Eastern Tethys in the Eastern Mediterranean region into several small ocean basins, which rifted at more or less the same time in latest Triassic–earliest Jurassic time. All of the rifted margins of the Eastern Tethys are associated with rift-related volcanic rocks. However, with the exception of the Permian Panjal Traps in the Himalayas, the volumes of magma and corresponding thermal doming were less than for the ideal Volcanic-rifted margin (i.e. eastern Greenland). None of the Eastern Tethyan rifted margins show evidence of features characteristic of Non-volcanic rifted margins (e.g. sea-floor serpentinite exhumation), in contrast to the Iberia–Newfoundland conjugate or the Alps. Most of the Eastern Tethyan rifted margins appear to correspond to an ‘intermediate’ type, characterized by pulsed rifting, limited rift volcanism and a narrow continent–ocean transition zone. Such ‘intermediate-type’ rifted margins may remain to be explored in the modern oceans by deep-sea drilling. There is little evidence to support previous suggestions that the Eastern Tethyan rifts can be considered as back-arc basins above either northward- or southward-dipping subduction zones. Here it is suggested that the Eastern Tethys documents a fundamentally different type of rifting from either the ‘Volcanic-related’ or ‘Non-volcanic’ intracontinental rifts known from the Alps or the North Atlantic region. The dominant controls of rifting are seen as the traction of rising asthenosphere on the base of the lithosphere, related deviatoric tensional stresses, inherited and thermally induced weaknesses in the crust, and slab-pull. Specifically, in the Eastern Tethyan region continental breakup was probably triggered by a combination of long-term asthenosphere flow, slab-pull related to subduction beneath Eurasia and melt-induced crustal weakening associated with pulsed rifting or plume effects. Final continental breakup corresponds to a major (‘Cimmerian’) convergent phase along the opposing Eurasia margin, which further supports the role of plate boundary forces in Eastern Tethyan rifting. The early Mesozoic oceanic basins opened, probably associated with northwestward propagation of a spreading centre through the already weakened periphery of Gondwana, adjacent to less deformable Palaeotethyan oceanic crust. After a lengthy period of passive margin subsidence, locally punctuated by crustal extension and related volcanism, or plume effects, the rifted margins were finally tectonically emplaced during mid-Mesozoic, late Mesozoic or early Cenozoic time in different areas.

The prelude of the end-Permian mass extinction predates a postulated bolide impact

The mass extinction at the Permian–Triassic Boundary (PTB) is said to have been abrupt and probably caused by an extraterrestrial impact. However, evidence from the Global Stratotype Section and Point (GSSP) of the base of the Induan at Meishan, China, shows that the biotic crisis began prior to the level, in beds 25 and 26 at which the postulated impact event occurred. Evidence of such an earlier biotic crisis occurs in other sections in South China, and in central and western Tethyan regions. This event is characterized by the extinction of a range of faunas, including corals, deep-water radiolarians, most fusulinids and pseudotirolitid ammonoids, and many Permian brachiopods. In all sections, this extinction level is usually a few decimeters to meters below that of the main mass extinction in the event beds (25 and 26) at Meishan, and their correlatives elsewhere. This earlier extinction event happened before the postulated bolide impact at the level of beds 25 and 26, and constrains interpretation of the mechanisms that brought about this greatest mass extinction.

A LONG‐BODIED LIZARD FROM THE LOWER CRETACEOUS OF JAPAN

Abstract: Platynotan lizards underwent a dramatic Late Cretaceous radiation into marine habitats. Beginning with small‐bodied forms, the lineage culminated with the mosasaurs, large predatory lizards with a world‐wide distribution in the Santonian–Campanian. Moreover, the marine squamate radiations of the Cenomanian–Turonian are remarkable in having produced a range of long‐bodied, reduced‐limbed swimmers (dolichosaurs, adriosaurs, coniasaurs and limbed snakes) that seem to have thrived in the shallow coastal environments of the Western Tethys region. Until now, none of these long‐bodied aquatic squamates has been recorded prior to the Cenomanian, none has been recovered from a non‐marine locality and none is known from Asia. Here we describe a small, gracile, long‐bodied mosasauroid lizard from a swampy continental deposit in the Lower Cretaceous of Japan.

A PAPER NAUTILUS (OCTOPODA, ARGONAUTA) FROM THE MIOCENE PAKHNA FORMATION OF CYPRUS

Abstract: The fossil organic trace of an argonaut shell from the Pakhna Formation (Serravillian, Middle Miocene) of southern Cyprus is described. The new find represents one of only a very few argonaut egg cases reported from the fossil record of the Tethyan region and is the first to be reported from the eastern Mediterranean. It is assigned to a new species of Argonauta as A. absyrtus sp. nov.

An eastern Tethyan (Tibetan) record of the Early Jurassic (Toarcian) mass extinction event

ABSTRACTA record of the Early Jurassic mass extinction event is reported from eastern Tethyan (Tibetan) locations for the first time. In the Mount Everest region a thick Lower Jurassic carbonate formation, here named the Yungjia Formation, is developed within the predominantly clastic Triassic–Jurassic succession. Within the formation a sharp transition from peloidal packstones/grainstones to thin‐bedded, pyritic micrite‐shales interbeds records a sharp pulse of deepening and development of dysoxic bottom waters. Both the lithiotid bivalves and the lituolid foraminifera are important constituents of the lower Yungjia Formation but they disappear at this flooding surface or a short distance below it. This extinction event is comparable to that seen at the base of the Pliensbachian/Toarcian boundary in western Tethyan platform carbonates but the Tibetan events occurred late in the Toarcian Stage as indicated by nannofossil biostratigraphy and C isotope chemostratigraphy. The Early Jurassic extinction event (and the associated spread of oxygen‐poor waters) was therefore not synchronous throughout the Tethyan region.

Subduction history of the Tethyan region derived from seismic tomography and tectonic reconstructions

In the mantle underneath the Tethyan suture zone, large volumes of positive velocity anomalies have been imaged by seismic tomography and interpreted as the present‐day signature of subducted Tethyan lithosphere. We investigate the Mesozoic‐Cenozoic subduction history of the region by integrating independent information from mantle tomography and tectonic reconstructions. Three different subduction scenarios for the Tethyan oceanic lithosphere, representative for the available tectonic reconstructions, are used to predict the present thermally anomalous volumes associated with the lithospheric surface subducted since the late Mesozoic. Next, these predicted thermal volumes and their expected positions are compared to the relevant anomalous volumes derived from seismic tomographic images. In this analysis we include, among others, the possible effects of ridge subduction and slab detachment after the Cenozoic continental collisions, absolute plate motion, and slab thickening in the mantle. Our preferred subduction model comprises the opening of large back‐arc oceanic basins within the Eurasian margin. The model points to slab thickening by a factor of 3 in the mantle, in which case the estimated volumes allow for active oceanic spreading (∼1–2.5 cm/yr) in the Tethyan lithosphere during convergence. Our results further indicate the occurrence of early Oligocene slab detachment underneath the northern Zagros suture zone, followed by both westward and eastward propagation of the slab tear and diachronous Eocene to Miocene slab detachment below the eastern to western Himalayas. Free sinking rates of the detached material of ∼2 cm/yr in the lower mantle provide the best fit between the tomographic mantle structure and our Tethyan subduction model.

A Study of Global Vertical Velocity of Mantle Flow

AbstractBased on the high resolution body wave tomographic images and relevant geophysical data we calculated the form and vertical velocity of mantle flow, and obtained the global vertical moving pattern of mantle flow. On a globe scale the mantle flow can be divided into several regions, the two large‐scale mantle downwelling regions in Eurasian‐Australian continents and North American‐South American continents, and two large‐scale mantle upwelling regions in the mid and south Pacific Ocean and west Indian Ocean‐African‐Atlantic Ocean, The mantle upwelling is originated from the core‐mantle boundary and mostly presents in the middle mantle and lower part of the upper mantle. The velocity of vertical mantle flow is about 1 to 4 cm per year. The mantle flow controls plate motions and the distributions of ocean ridges, subduction zones and collision zones. The mantle upwelling regions are clearly related with locations of hot‐spots on the earth's surface. There is an upwelling plume beneath East Asia and western Pacific which is earth's deep origin for huge rifts. Siberian clod downwelling dives from the surface to near CMB. The tethyan diving region centred in the Qinghai‐Tibet Plateau is visible. The three regions of mantle convection beneath East Asia and western Pacific agree with tectonic features of western Pacific, Asia and tethyan regions.

Correlation of reefal Oxfordian episodes and climatic implications in the eastern Paris Basin (France)

AbstractOxfordian reefal episodes of Lorraine and Burgundy have a long time been considered as contemporaneous. Biostratigraphic data and sequential evolutions peculiar to each region indicate their structural autonomy during Oxfordian times. A north‐south‐oriented well‐logging transect shows that, during the Middle Oxfordian, a shallow reefal platform developed in Lorraine while thin deeper deposits occurred in Burgundy. In spite of their different ages, reefal episodes of Middle Oxfordian in Lorraine and Upper Oxfordian in Burgundy exhibit a broadly similar vertical evolution of coral communities. During the Late Oxfordian, the contemporaneous occurrence of a diversified assemblage in the Burgundy region, a colder coral assemblage characterized by eurytopic genera and the decrease in seawater isotopic temperatures in Lorraine can be explained by a shift in trophic conditions, a climatic change related to structural rearrangements in this strategic place and a modification of oceanic circulations between the arctic and the Tethyan regions.

Survival brachiopod faunas of the end-Permian mass extinction from the southern Alps (Italy) and South China

Eight brachiopod species in seven genera are described from the Permian–Triassic boundary beds of South China and northern Italy. The brachiopods from northern Italy are described for the first time and include two new species: Orbicoelia dolomitensis Chen and Spirigerella? teseroi Chen. The Permian affinity of these brachiopods and their stratigraphical position above the extinction horizon demonstrate that they are survivors from the end-Permian mass extinction. The surviving brachiopods from South China, which was located at the eastern margin of the Palaeo-Tethys Ocean, are considerably abundant and diverse and are dominated by geographically widespread generalist elements adapted to a wide variety of environments. They were mostly limited to the Upper Permian to lowest Griesbachian. In contrast, the survivors in northern Italy, which was situated at the western margin of the Palaeo-Tethys, comprise elements ranging from the Carboniferous to Permian or widespread Tethyan genera. These survivors did not occur in the pre-extinction western Tethyan oceans but migrated into this region after the end-Permian extinction event. Disaster taxon Lingula proliferated slightly earlier in western Tethyan oceans than in eastern Tethyan regions following the event. Survival brachiopods from both regions appear to have a generic affinity, although they do not share any species. Both South Chinese and Italian survival faunas support the view that the survival interval is the duration when survivors are dominated by geographically widespread generalist organisms adapted to a wide variety of ecological conditions.