Franz T. Fürsich

The Aptian-Albian Romualdo Formation was deposited in a confined aquatic setting marked by at least three distinct marine ingression events. Most paleontological knowledge of this unit derives from the shale-dominated interval in its middle part, while fossil data from the sandstone-dominated facies in the uppermost part of the formation remain sca...

The siliciclastic Bajocian–Bathonian Pelion Formation of Tværdal, Geographical Society Ø, East Greenland, is dominated by shallow-marine sandstones, which yielded 22 bivalve taxa representing 18 genera; these are described and figured here. The type species of the subgenus Strimodiolus, Modiolus (Strimodiolus) elongatus Fürsich, 1982, is a junior h...

Event deposition accounts for a large part of the preserved sedimentary record. Tempestites, tsunamites and turbidites are among the most common event deposits in marine and lacustrine systems. While facies models exist for these deposits, the challenge lies in the fact that diverse triggers can give rise to analogous depositional processes and com...

The fossil-rich Romualdo Formation (late Aptian/early Albian), Araripe Basin, northeastern Brazil, contains world-renowned Fossillagerstätten characterized by exceptionally preserved fossils. Macroinvertebrates in this formation are primarily represented by mollusks, echinoids, and decapod crustaceans. Mollusk shells are abundant in certain stratig...

In their detailed comments, Das et al. (2023) try to discount our arguments that the strata cropping out at the so-called Jhura pond locality are not Late Jurassic in age but Miocene. We wrote this paper (Fürsich et al., 2023) because of the far-reaching conclusions that have been drawn from the molluscan fauna at that locality, in particular with...

A summary of the present stage of our knowledge on the Jurassic sedimentary succession of the basins along the western and northern shelf areas of the Indian craton is presented with a particular focus on the progress in the last four years (2019–2023). Concerning the Jurassic lithostratigraphy of the Kachchh and Jaisalmer basins along the western...

The Jurassic trigoniid bivalves of Gebel Maghara, northern Sinai, Egypt are described and figured. They belong to 14 species, nine genera, and two families. The identified taxa occur in rocks ranging in age from the Toarcian (Lower Jurassic) to the lower Kimmeridgian (Upper Jurassic). Five genera and one species are new: Magharitrigonia asymmetrica...

Fossils from the Araripe Basin (northeastern Brazil) are known for their remarkable preservation of vertebrates and invertebrates, even including soft tissues. They occur in carbonate concretions within organic carbon‐rich strata assigned to the Romualdo Formation. Here we present integrated stable isotope, elemental and microfossil records from th...

The known occurrences of Early Cretaceous freshwater bivalves in the Araripe Basin are confined to the 0.85- to 2-m-thick Caldas Bed of the Crato Formation. Herein, we record a new bivalve-dominated assemblage in a siltstone bed nearly 30 m below the upper boundary with the overlying Romualdo Formation. The assemblage is composed of ecologically in...

This is a comment to an article previously published in The Depositional Record .

The early Mesozoic witnessed evolution of novel bivalve groups and innovation of diverse ecologic strategies. Although some newly evolved groups disappeared (e.g., Harpax), some persist until today (e.g., Cuspidariidae, Thyasiridae). Harpax (Norian-early Toarcian) is a globally widespread genus and a secondary soft substrate recliner, cemented to s...

The Jurassic Bivalve Catalogue is the most comprehensive and complete data compilation of published Jurassic bivalve occurrences. The Catalogue has been compiled by F.F. and W.W. since the beginning of 80s to facilitate taxonomic and palaeogeographic analyses. The Catalogue is stored at the Bavarian State Collection for Palaeontology and Geology, M...

The Kachchh Rift Basin began to form during the Late Triassic at the western margin of the Indian Craton and went through the syn-rift stage during the Jurassic. Initially filled with terrestrial sediments, the first marine ingression occurred probably as early as the Pliensbachian but was short-lived. From the Early Bajocian onwards, marine sedime...

The Upper Kimmeridgian-basal Tithonian clastic sequence at Santa Cruz, Estremadura, repre sents environments ranging from river channels and flood plains to lagoons and protected bays showing a deltaic influence. Within the marginal marine environments, five benthic macroinvertebrate associations are recognized and analysed in terms of diversity an...

The Jurassic rocks of Gebel Maghara, northern Sinai, Egypt, contain a well-preserved and highly diverse macrobenthic fauna, dominated by bivalves. This fauna, particularly bivalves and gastropods, have received little attention in the last 100 years. In an attempt to provide a sound database on the marine bivalve diversity of Egypt during the Juras...

A diverse molluscan assemblage dominated by turritellid gastropods found in Kachchh, western India, has been interpreted in the past as Late Jurassic (Oxfordian) in age, based on associated undoubtedly Oxfordian ammonites. Recently, several investigations focused on the assemblage dealing with taxonomic, paleoecological, and evolutionary aspects. A...

Abstract The Middle Jurassic Kashafrud Formation of the Kopet-Dagh Basin is a succession of fluvial to turbiditic siliciclastic rocks deposited in a rift basin that was initiated in the Late Bajocian and was filled with conglomerates, sandstones, and mudstones. The sandstones are mainly lithic arkoses and feldspathic litharenites. The sandstones of...

Abstract The present study describes and illustrates six bivalve taxa from the Early Bathonian to Early Callovian Ferruginous Oolite Formation and 24 taxa from the Callovian to basal-most Cretaceous Spiti Shale Formation of the Spiti and Zanskar areas in the Indian Himalayas. The Spiti Shale Formation contains a low-diversity bivalve fauna that i...

The Aptian Romualdo Formation (Araripe Basin, NE Brazil) was deposited in a restricted epeiric sea, during the opening of the South Atlantic Ocean, with a coeval record to that in the Brazilian Pre-Salt succession. The upper part of the Romualdo Formation encompasses the Highstand Systems Tract of a third-order stratigraphic sequence, and contains...

Stable oxygen isotope values of calcitic marine fossils (δ¹⁸Oshell) were used to calculate the first absolute seawater temperature estimates for the Jurassic of Central Iran. Results indicate a significant long-term warming in the study area through the Middle to Late Jurassic of around 6 °C or more (0.3 to 0.4 °C per million years). Following rece...

Under the complex influences including the monsoonal climates and tropical hydrological cycle, the features and forcing mechanisms of precipitation changes in the tropical monsoon regions remain controversial. The northern coast of the South China Sea (NCSCS), connecting the South China Sea (SCS) and the Pearl River Estuary (PRE), is a critical are...

The Himalayan Tethyan sequence documents a significant transgressive event from Late Triassic to Middle Jurassic. The transgressive events represent thick carbonate deposits overlying the Late Triassic carbonate reef environment. A systematic study of the sections at the top of Kioto Limestone deposits in the Spiti Valley reveals a Middle Jurassic...

A Hildoglochiceras -rich horizon is reported from a thin carbonate intercalation within the siliciclastic Upper Jurassic Jhuran Formation of the Jara Dome, western Kachchh Mainland. The Hildoglochiceras specimens have been used for the first population-level study of the genus based on a multivariate analysis. High phenotype instability in the larg...

The stable isotope (δ¹³C, δ¹⁸O) and element (Mg/Ca, Sr/Ca) composition of 374 well-preserved belemnites, bivalves, and brachiopods of the Kachchh and Jaisalmer basins in western India were used to reconstruct climatic changes in the Middle and Late Jurassic time interval. Absolute water temperatures reconstructed from δ¹⁸Oshell values depend on the...

Several well-preserved impressions of Ptilophyllum and Cladophlebis from the Upper Kimmeridgian part of the Jhuran Formation at the Jhuran River are described and illustrated. The presence of well-preserved leaf fossils and plant debris suggest an increasing terrestrial influence during the filling of the Kachchh Basin in the Late Jurassic. A lone...

A late early Maastrichtian dinosaur trampling site is reported from the Farrokhi Formation of the Khur area, Central Iran. The largely indeterminate footprints, some of which may represent undertracks, can be classified as natural moulds (i.e. concave epireliefs) bordered by a raised rim of displaced sediment. They reach diameters of up to 0.5 m an...

Middle to Late Jurassic belemnites from the Spiti and Zanskar valleys in the Indian Himalayas were used for stable isotope (δ ¹³ C, δ ¹⁸ O) and element (Mg/Ca, Sr/Ca) analyses. Although the Himalayan orogeny deformed and altered a large portion of the collected fossils, cathodoluminescence and scanning electron microscopy in combination with analys...

The Lower Jurassic Mashabba Formation crops out in the core of the doubly plunging Al-Maghara anticline, North Sinai, Egypt. It represents a marine to terrestrial succession deposited within a rift basin associated with the opening of the Neotethys. Despite being one of the best and the only exposed Lower Jurassic strata in Egypt, its sedimentologi...

Paraboliceras is a widely distributed ammonite genus of the Indo-Pacific Realm recorded from the Spiti Himalaya to New Zealand. It has been recorded as an index fossil of Kimmeridgian strata in the Nepal Himalaya, but has also been recorded in the Tithonian strata of the Indian Himalaya. Paraboliceras evolved apparently in New Zealand from the Late...

The Spiti Shale Formation is a widely distributed stratigraphic unit of the passive northern margin of the Indian craton, deposited between the Callovian and earliest Cretaceous. The siliciclastic strata are dominated by dark-grey to black argillaceous silt. As the formation has undergone intense tectonic stress involving folding and faulting, it i...

The Kimmeridgian Alcobaça Formation of the Lusitanian Basin forms a mixed carbonate–siliciclastic unit between basinal deposits of the Abadia Formation, and fluvial–terrestrial strata of the Lourinhã Formation. This study presents >2.5 km of detailed logs of nine outcrop sections of the Alcobaça Formation in its type region. Eight of these sections...

Protandrous sex change (sex change from male to female) is one of the diverse sexual expressions exhibited by bivalves, but its expression in the shell is quite rare. Previous studies on living and fossil astartids suggest a relationship between protandrous sex change and the formation of crenulations on the ventral shell margin at later ontogeneti...

Lithostratigraphy and biostratigraphy of Middle to Upper Jurassic carbonate platforms of the Eastern Kopet Dagh (EKD), northeastern Iran were assessed. Up to 3000 m of sedimentological logs located along ten stratigraphic sections were investigated. At least five types of carbonate production systems were identified in the study area: (1) a mud-dom...

Brachyurans played important ecological and evolutionary roles in the marine benthic communities of the past and were the components of the Mesozoic Decapod Revolution. Therefore, the search for their fossil remains is fundamental to understanding the composition, diversity, and ecological structure of Mesozoic marine benthic communities. Brachyura...

Macroids, cm-sized biogenically coated grains made of associations of metazoans or protozoans, accumulate in some high-frequency sedimentary sequences of the upper Hauterivian to lower Barremian Agua de la Mula Member of the Agrio Formation in the Neuquén Basin (northern Patagonia, Argentina). The macroids studied are sub-spheroidal and sub-discoid...

The Garedu Red Bed Formation (GRBF) of the northern Tabas Block (Central-East Iranian Microcontinent, CEIM) is a lithologically variable, up to 500-m-thick, predominantly continental unit. It rests gradually or unconformably on marine limestones of the Esfandiar Subgroup (Callovian–Oxfordian) and is assigned to the Kimmeridgian–Tithonian. In the lo...

The siliciclastic Jhuran Formation of the Kachchh Basin, a rift basin bordering the Malagasy Seaway, documents the filling of the basin during the late syn-rift stage. The marine, more than 700-m-thick Tithonian part of the succession in the western part of the basin is composed of highly asymmetric transgressive–regressive cycles and is nearly unf...

The Aptian Crato Formation is world renowned for its well-preserved fossils in microbially-induced laminated limestones, which are regarded as one of the main Cretaceous Konservat-Lagerstätte of the geological record. Detailed stratigraphic investigation and mapping of the up to 90-m-thick Crato Formation at the eastern border of the Araripe Platea...

Drill holes provide valuable information about palaeoecological interactions in fossil ecosystems, but the Jurassic drill‐hole record is scarce. We report circular drill holes in the infaunal bivalve Eothyasira antiqua (Münster in Goldfuss) from the Pliensbachian grey shales of the Amaltheenton Formation of Franconia, southern Germany. The outcrop...

Previous stable oxygen isotope records of calcitic fossils (δ18Oshell) from Europe have been interpreted to reflect strong climatic perturbations throughout the Jurassic, but it is unknown whether they reflect global trends because data from other regions are sparse. Here, we use bivalve and brachiopod shells from western Asia and northern Africa t...

The plicatulid bivalve Harpax spinosus is a common element of Pliensbachian to Lower Toarcian benthic community relicts occurring preferredly in fine-grained siliciclastic and mixed carbonate-siliciclastic sediments. There is general agreement that the bivalve was a secondary soft substrate dweller, being cemented with its flat to slightly concave...

New Aptian (Lower Cretaceous) bakevelliid bivalves are described for the Romualdo Formation, Santana Group, Araripe Basin, northeastern Brazil. Together with the other known member of the family Bakevelliidae, already recorded from the unit (i.e., Aguileria dissita), the new bivalves (Araripevellia musculosa gen. et sp. nov., Aguileria romualdoensi...

Two new taxa of freshwater mussels (Bivalvia: Unionida) from the Aptian Crato Formation of the Araripe Basin, NE Brazil, are described. The fossil bivalves are confined to 30- to 130-cm-thick bioturbated mudstones overlying the fossil-rich laminated limestones of the Crato Formation Konservat-Lagerstätte. Individuals are often preserved with closed...

The Jurassic Bazeh-Howz Formation is a succession of braided river siliciclastics deposited in an intramontane basin. Three major types of facies, conglomerate, sandstone and shale, have been identified. Conglomerates are mainly monomict and polymict orthoconglomerates. The sandstones are quartzarenites, sublitharenites, feldspathic litharenites an...

The dark clays of the Lower Jurassic (Upper Pliensbachian) Amaltheenton Formation in Buttenheim, Franconia yield a diverse and well-preserved benthic and nektonic macrofauna, dominated by bivalves, gastropods, and ammonites. In the present study the bivalve fauna is described based on new collections of ca. 7000 specimens. A comprehensive taxonomic...

Biostratigraphy of ammonite, inoceramid and orbitolinid foraminifer faunas from the mid-Cretaceous (Aptian–Turonian) succession at the eastern border of the Anarak Metamorphic Complex, a basement uplift in the north-western part of Central Iran, helped to understand complex lithostratigraphic patterns, to trace tectonic unconformities and to recons...

Abstract The stable isotope (δ13C, δ18O) composition of a collection of Lower Jurassic brachiopods and oysters from the Andean Basin of northern Chile was analyzed. The results allow the first reconstruction of absolute water temperatures for several ammonite zones in the Lower Jurassic of South America. The temperature record starts with comparati...

The dark clays of the Amaltheenton Formation (Pliensbachian, Spinatum Zone) of Franconia (N Bavaria) yield a diverse and well-preserved macrofauna. Together with gastropods, bivalves form the most abundant and diverse benthic group. The last taxonomic study on the Pliensbachian bivalves from Franconia was done by Kuhn in the 1930ies. We studied, fr...

In early July, a group of paleobotanists announced the discovery of a fossil of a new lily species, Cratolirion bognerianum, which lived 115 million years ago. The delicacy of the specimen, with its roots, petals, and even individual cells preserved, impressed the researchers. The site where the flower was found, however, was not surprising—the Cra...

The Aptian Crato Konservat-Lagerstätte is renowned for its exceptionally preserved fossils in lacustrine laminated limestones. Although previous works on this site include numerous taxonomic studies, its taphonomy remains a subject of debate. Herein, we present new data on the taphonomy of decapod crustaceans preserved in wrinkle laminites, highlig...

verview Stats Comments Citations (1) References (125) Related research (10+) Share Save Share on Twitter Abstract and figures Abstract Middle and Upper Jurassic bivalves from the southwestern Morondava Basin are described and figured. They belong to 74 species and 57 genera/subgenera. New taxa are Eosphaera gen. nov., Neocrassina (Pruvost...

Sixteen early and middle Albian bivalve species, belonging to fourteen genera, eleven families and seven orders, and one brachiopod species are systematically described from the Mitrovčić section near Topola (Oplenac Hill), Vardar Zone of central Serbia. Four bivalve species: Acesta subrigida (Roemer, 1836), Acesta cf. dorbignyana (Mathéron, 1843),...

Abstract Middle and Upper Jurassic bivalves from the southwestern Morondava Basin are described and figured. They belong to 74 species and 57 genera/subgenera. New taxa are Eosphaera gen. nov., Neocrassina (Pruvostiella) madagascariensis sp. nov., and Quenstedtia madagascariensis sp. nov. Most of the bivalves come from Callovian and Oxfordian strat...

The Aptian Romualdo Formation is a siliciclastic-dominated sedimentary unit recording the last marine ingression within the Cretaceous interior basins of northeastern Brazil. At the western margin of the Araripe Basin, rocks of the Romualdo Formation are mainly represented by carbonates resting abruptly over the Proterozoic crystalline basement. De...

Fifty heterodont bivalve species, belonging to 35 genera, 15 families and six orders, from the Cenomanian–Coniacian Cotinguiba Formation of the Sergipe Basin, north-eastern Brazil, are systematically described and figured. Thirty-three species are recorded from the basin for the first time. The new species Callucina (C.) itaporangensis sp. nov. fro...

The density of vertebrate fossils on bedding planes is generally very low in the Upper Jurassic plattenkalks forming the Solnhofen fossil Lagerstätte. There are, however, a few bedding planes where large concentrations of the small fish Leptolepides sprattiformis (Blainville, 1818) occur. The aim of this paper is to analyse and interpret these fish...

Stable isotope (δ ¹⁸ O, δ ¹³ C) analyses were performed on well preserved belemnites, oysters, and rhynchonellid brachiopods from the Middle to Upper Jurassic of the Morondava Basin in southern Madagascar. Both brachiopods and oysters indicate similar average temperatures of 18.7 to 19.3 °C in the Early Callovian, followed by a temperature decrease...

The Wagad Uplift is a region in the eastern part of the Kachchh Basin of western India which exposes Middle to Upper Jurassic sedimentary rocks. The more than 520 m thick succession is dominated by third-order cycles with highstand systems tracts being composed of coarsening-upwards parasequences. The Callovian to Lower Oxfordian succession is domi...

The palaeoecology of Spinicaudata, the dominant group of benthic invertebrates in many pre-Cenozoic freshwater environments, remains poorly understood. In analogy with extant taxa, it has been oversimplified and often reduced to shallow, temporary environments characterized by few trophic levels, implying ecological stasis from the Devonian to the...

A set of two to three prominent hardgrounds can be traced for more than 40 km from east to west within the Jurassic succession of the Jaisalmer Basin at the western margin of the Indian Craton. The hardgrounds started to form under subtidal conditions in a mixed carbonate–siliciclastic setting during the last phase of a transgressive systems tract,...

The Cretaceous (upper Aptian) Romualdo Formation of the Araripe Basin, northeastern Brazil, is a marine-influenced, predominantly fine-grained siliciclastic unit. In the eastern part of the basin, it corresponds to a depositional sequence composed of two transgressive-regressive cycles. Low-diversity benthic macrofaunas document high-stress conditi...

The Upper Albian–Turonian Debarsu Formation in its type area around Haftoman, south of Khur (Central Iran) has been investigated using an integrated approach of high-resolution logging, bio- and sequence stratigraphic dating, and facies analysis based on field observations and detailed microfacies studies. The up to 500-m-thick Debarsu Formation co...

Thirty Kimmeridgian (Upper Jurassic) ammonite specimens of the genera Torquatisphinctes, Pachysphinctes, Katroliceras, and Indodichotomoceras collected from two horizons in the eastern part of the Kachchh Basin were phenetically classified. First, 23 morphological characters were selected for the analysis. The difference matrix was generated by tre...

By combination of data from lithological, geochemical and taphonomic investigations, the palaeoenvironmental conditions and depositional history of the middle Kimmeridgian Wat-tendorf Plattenkalk of Southern Germany were reconstructed. The Wattendorf Plattenkalk, the stratigraphically oldest occurrence of lithographic limestone from Southern German...

A total of 93 surface sediment samples were collected to analyze the environmental factors constraining the foraminiferal distribution pattern in the southern South China Sea (SCS). Species distributions and stable isotopic compositions were combined to reveal the controlling factors, such as depth, salinity, substrate, runoff, currents, and cold s...

An integrated study of the litho-, bio-, and microfacies of several sections has greatly improved the knowledge on the stratigraphy and depositional setting of the Coniacian to Campanian Haftoman Formation in the Khur area of the northern Yazd Block, Central Iran. Generally, the Haftoman Formation rests on a major tectonic unconformity and commence...

The “Jurassic Gap” between Upper Triassic and Lower Cretaceous siliciclastic strata at the southwestern margin of the Central East Iranian Microcontinent (CEIM) represents the Cimmerian orogenic events. However, the provenance of siliciclastic rocks above and below this prominent unconformity is poorly known, negatively affecting our ability to rec...

Gangta Bet, situated between the Wagad Uplift and Khadir Island in the Kachchh Basin, is composed of Callovian to Oxfordian fossiliferous sedimentary rocks, in which brachiopods are an important component, especially in a local marker horizon (the Brachiopod Bed). In total, six taxa are discussed here: Bihendulirhynchia brevicostata, Kallirhynchia...

The uppermost part of the Upper Bathonian Sponge Limestone member, Patcham Formation, of the Jhura Dome of Kachchh Mainland is a thickening- and shallowing-upward succession topped by medium- to thick-bedded hummocky cross-stratified grainstones deposited by storm waves. Occasionally, thin, commonly lenticular, intraclastic–bioclastic silty marl in...

Unresolved taxonomic issues regarding spinicaudatans, clam shrimps that formed the most abundant faunal element in the lacustrine Barremian to Aptian Yixian Formation, have hampered palaeoecological and evolutionary interpretations of this key fossil group. Here, we analyse morphological variability in East Asian clam-shrimp taxa by quantifying: (1...

An articulated and partially preserved skeleton of an ichthyosaur was found in the Upper Jurassic (Upper Kimmeridgian) Katrol Formation exposed at a site south of the village Lodai in Kachchh district, Gujarat (western India). Here we present a detailed description and inferred taxonomic relationship of the specimen. The present study revealed that...

The Lower Jurassic Ab-Haji Formation consists of siliciclastic strata which are widespread and superbly exposed across the Tabas and Lut blocks of east-central Iran. The formation records the geodynamic history of central Iran during the Early Jurassic in the aftermath of the main Cimmerian event (near the Triassic–Jurassic boundary) through its se...

Taphocoenoses can be powerful indicators of ancient environments, even in depositional settings in which rates of sedimentation are low and tidal currents are strong. The rich subtropical mollusc fauna of the northern Gulf of California exhibits a distinct zonation across an extensive tidal flat at Bahia la Choya (Sonora, Mexico). The distribution...

Geologic events related to the opening of the South Atlantic Ocean deeply influenced the sedimentary record of the Araripe Basin. As consequence, upper stratigraphic units of the basin record a marine ingression in northeastern Brazil during the late Aptian. The timing and stratigraphic architecture of these units are crucial to understand the pale...

This is the first record of a Permian seep deposit and an associated, morphologically bizarre, bivalve-dominated fauna from the Passa Dois Group, Paraná Basin, Brazil. Shales of the outer-shelf facies of the Serra Alta Formation preserve a low-diversity but high-abundant, large-sized bivalve fauna with unusual morphologies inside discoidal carbonat...

This study focuses on the controlling factors on the sedimentation and stratigraphic evolution of the Lower Jurassic Mashabba Formation that is cropping out at the core of the NE-SW oriented doubly plunging anticline Al-Maghara, North Sinai, Egypt. The study provides also a criterion in addition to tidal signals to define the fluvio-marine transiti...

The Jurassic succession of Gangta Bet in the Kachchh basin of western India comprises around 130 m of mostly siliciclastic rocks. The strata belong to the Gangta Member of the Gadhada Formation and are herein sub-divided into four units: the Gangta sandstone beds, the lower silty sandstone beds, the upper silty sandstone beds, and the Gangta ammoni...

The nuculanid bivalve Costinuculana magharensis new genus new species is described from the middle to upper Bathonian Kehailia Formation of Gebel Maghara, North Sinai, Egypt. Costinuculana differs from other genera of the family Nuculanidae by the presence of opisthocline ribs along the rostrum. These ribs are variable in shape and size, straight t...

Abstract.—The nuculanid bivalve Costinuculana magharensis new genus new species is described from the middle to upper Bathonian Kehailia Formation of Gebel Maghara, North Sinai, Egypt. Costinuculana differs from other genera of the family Nuculanidae by the presence of opisthocline ribs along the rostrum. These ribs are variable in shape and size,...

Abstract.—The nuculanid bivalve Costinuculana magharensis new genus new species is described from the middle to upper Bathonian Kehailia Formation of Gebel Maghara, North Sinai, Egypt. Costinuculana differs from other genera of the family Nuculanidae by the presence of opisthocline ribs along the rostrum. These ribs are variable in shape and size,...

The type section of the Middle and Upper Jurassic Chaman Bid Formation is in the western Koppeh-Dagh Basin (Northeast Iran). It is unusually thick and contains a rather rich ammonite fauna, ranging from Bathonian to Tithonian. The ammonites described here come from a 134-m-thick interval in the upper part of member (D) in the middle part of the for...