Lower Cretaceous Deposits Research Articles

On Late Jurassic–Early Cretaceous oysters of the genus Deltoideum Rollier (Bivalvia, Ostreoidea) from Siberia

Morphology, palaeoecology, and phylogeny of oysters of the genus Deltoideum Rollier from the Upper Jurassic and Lower Cretaceous deposits of Siberia are discussed. The diagnosis and composition of the genus are revised. A new endemic subgenus, Boreiodeltoideum subgen. nov., of the genus Deltoideum is described. This subgenus includes two species, D. (B.) praeanabarensis (Zakharov) and D. (B.) anabarensis (Bodylevsky).

Lower Cretaceous gastropods from the Qayen area, Eastern Iran

Four gastropod genera are newly recorded from Lower Cretaceous deposits of the Qayen area, Eastern Iran. Based on the paleoecological interpretation of the faunal assemblage and especially on the newly identified gastropods, a shallow temperate marine environment is suggested for the fossil-bearing carbonate rocks. The gastropod assemblage shows a typically Tethyan composition comparable to those already reported from the Caucasus and Eastern Europe.

Laminae-scale rhythmicity of inclined heterolithic stratification, Lower Cretaceous McMurray Formation, NE Alberta, Canada

Abstract Inclined Heterolithic Stratification, characterized by dipping, interbedded and interlaminated sandstone and mudstone lithosomes comprises a major portion of the Athabasca Oil Sands. Fluvial processes have generally been interpreted to be the major cause of lithological variations and accompanying cyclicity in Inclined Heterolithic Stratification. The objectives of this research are applying quantitative and visual frequency analysis techniques, to determine and interpret the laminae-scale cyclicity of Inclined Heterolithic Stratification lithosomes. The Inclined Heterolithic Stratification in the Pierre River area is subdivided into five lithosomes based on distinct ichnological and sedimentological features. For each lithosome, Continuous Wavelet Transforms, applied to measurements of laminae or bed thicknesses, treated as pseudo time-series, converts these time-series to the frequency domain in order to determine the cyclicity of interlaminated portions of lithosomes. Visual identification of cycle breaks, by splitting series into cycles following troughs and peaks is completed as well. The results from the analysis demonstrate that the interlaminated portions of Inclined Heterolithic Stratification in the Pierre River Area preserve cyclic patterns that are consistent with semidiurnal synodic neap-spring tidal periodicity. Even in bioturbated intervals, interlaminated sandstone and mudstone is indicative of tidal cyclicity. The thicker sandstone or mudstone beds disrupting the tidally interlaminated portions of Inclined Heterolithic Stratification are interpreted to reflect variations in fluvial flux. This study gives a better understanding of the tidal regime during the lower Cretaceous McMurray Formation deposition and of the processes governing Inclined Heterolithic Stratification laminae-scale lithological variability.

NEW DATA ON ZEOLITE MINERALIZATION IN THE WEST SIBERIAN PLATE RESERVOIR ROCKS

The paper reviews the new data on the secondary zeolite mineralization characteristics for the Lower Cretaceous deposits of the West Siberian plate north. The authors suggest that the zone of distribution of altered rocks is much wider and in addition covers the area of Russkoye field. A new method of accounting of the volume of minerals of the zeolite group is proposed based on using the value of the volume fraction content of zeolites, which allows for a more qualitative approach to calculation of volumes of hydrocarbons in this type of reservoirs. It is shown that in major foreign deposits, complicated by the zeolitization processes, in order to improve the performance of the bottom-hole zone it is recommended to use a solution of hydrochloric acid.

New data from the Middle Jurassic of China shed light on the phylogeny and origin of the proboscis in the Mesopsychidae (Insecta: Mecoptera).

BackgroundThe Mesopsychidae is an extinct family of Mecoptera, comprising eleven described genera from Upper Permian to Lower Cretaceous deposits. In 2009, several well-preserved mesopsychids with long proboscides were reported from the mid Mesozoic of Northeastern China, suggesting the presence of pollination mutualisms with gymnosperm plants and highlighting their elevated genus-level diversity. Since that time, additional mesopsychid taxa have been described. However, the phylogeny of genera within Mesopsychidae has not been studied formally, attributable to the limited number of well-preserved fossils.ResultsHere, we describe two new species, Lichnomesopsyche prochorista sp. nov. and Vitimopsyche pristina sp. nov. and revise the diagnosis of Lichnomesopsyche daohugouensis Ren, Labandeira and Shih, 2010, based on ten specimens from the latest Middle Jurassic Jiulongshan Formation of Inner Mongolia, China. After compiling data from these new fossil species and previously reported representative taxa, we conducted phylogenetic analyses and geometric morphometric studies that now shed light on the taxonomy and phylogeny of Mesopsychidae. We also evaluate the recurring origin of the siphonate proboscis in the Mecoptera and propose an evolutionary developmental model for its multiple origins.ConclusionsPhylogenetic and geometric morphometric results confirm the establishment of two new species, each to Lichnomesopsyche and Vitimopsyche. Vitimopsyche pristina sp. nov. extends the existence of the genus Vitimopsyche Novokshonov and Sukacheva, 2001, from the mid Lower Cretaceous to the latest Middle Jurassic. Two methods of analyses indicate an affiliation of Mesopsyche dobrokhotovae Novokshonov, 1997 with Permopsyche Bashkuev, 2011. A phylogenetic analysis of the Mesopsychidae supports: 1), Mesopsychidae as a monophyletic group; 2), Mesopsyche as a paraphyletic group, to be revised pending future examination of additional material; and 3), the independent origin of the proboscis in the Pseudopolycentropodidae, its subsequent loss in earliest Mesopsychidae such as Epicharmesopsyche, its re-origination in the common ancestor (or perhaps independently) in the Vitimopsyche and Lichnomesopsyche clades of the Mesopsychidae. The third conclusion indicates that the proboscis originated four or five times within early Mecoptera, whose origin is explained by an evolutionary developmental model.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0575-y) contains supplementary material, which is available to authorized users.

Facies Analysis, Sedimentary Environment and Sequence Stratigraphy of the Lower Cretaceous Deposits in the Kalahroud Area, at North of Esfahan, Iran

Background/Objectives: Rocks of the Mesozoic era in Iran, especially Cretaceous period, have been studied frequently from stratigraphic point of view, but little research has been done from sedimentology viewpoint. This study aims to restore the sedimentation condition and the conditions governing the sedimentary basins during that period (lower Cretaceous). Methods: One stratigraphic section was measured along the outcrop in Kalahroud Area, at North of Esfahan. 52 thin sections samples were studied to determine the facies and a polarizan microscope was used for the procedure. Findings: Based on lithological properties, 3 lithostratigraphic units have identified in the area. Facies analysis and field observations led to identification of 6 carbonate facies, 4 terrigenous facies and also 3 mixed (terrigenous and carbonate). Kalahroud area was deposited on a homoclinal ramp setting within four zones including Continental, tidal flat, lagoon and bar environments. Sequence stratigraphic analysis identified one third-order depositional sequences in the studied area. Lower boundary in this sequence is unconformity first-type boundary (SB1) (with Jurassic deposits) and consists of Lowstand Systems Tract (LST), Transgressive Systems Tract (TST) and Highstand Systems Tract (HST). Application: These results could be used for comparison with other worldwide localities and provide additional data for lower Cretaceous paleogeographic reconstructions.

Paleoenvironmental distribution patterns of orbitolinids in the Lower Cretaceous deposits of eastern Rafsanjan, Central Iran

Abstract The Lower Cretaceous orbitolinid-rich deposits in eastern Rafsanjan, Central Iran were studied for analysis and interpretation of paleoenvironmental distribution patterns of orbitolinids. Based on detailed studies, a total of seven microfacies were determined. From the microfacies and paleontological studies the continental shelf (with a relative water depth of 0 to 20 m) can be separated into supralittoral, littoral–sublittoral transitional and sublittoral (includes proximal and distal sublittoral) paleoenvironmental zones. Orbitolinids with diverse test shapes were the main inhabitants of the sublittoral zone. The orbitolinids in this zone commonly represent nutrient-rich shallow warm waters of the photic zone with normal marine salinity (ca 30–40 psu) in a depth range of approximately 10 to 20 m. The general abundance or richness of orbitolinids in the sublittoral zone resulted from a nutrient-driven transgression. The studies showed that the conical orbitolinids were the most abundant forms in the sublittoral zone reflecting their better adaptation to different water depths, turbulence, light levels and substrate stability. However, the almost discoidal and discoidal orbitolinids were dominant in the middle part of the proximal sublittoral zone with a muddy substrate, deeper depth, lower water energy and decreased light intensity. All discoidal orbitolinids (slightly discoidal, almost discoidal and discoidal) were very rare and sparsely distributed in the distal sublittoral zone and the middle–outer part of the proximal sublittoral zone and generally reflect the highest sea-level rise or transgression, deepening, maximum nutrient enrichment and increased water cloudiness that can be correlated with a transgressive systems tract (TST) and probably maximum flooding surface (MFS). The lowest diversity and abundance of orbitolinids in the outer part of the proximal sublittoral zone commonly co-occurred with the presence of algal and sparse coral associations reflecting increased water temperature. Also, the absence of in situ orbitolinids in the littoral–sublittoral transitional zone resulted from high siliciclastic input and very high wave energy.

Morelletpora turgida (Radoičić, 1975 non 1965) a Tethyan calcareous green alga (Dasycladales): Taxonomy, stratigraphy and paleogeography

Pianella turgida, originally described from Cenomanian limestones of the external Dinarids, was subsequently transferred to the genus Salpingoporella. In the middle of the last century, Varma described the genus Morelletpora with Morelletpora nammalensis as type species from the Paleocene of India. Varma considered the new alga to be articulated, with club-shaped segments and only first order laterals. This foundation of Morelletpora was questioned for a long time. Attribution of a second species to Morelletpora, Morelletpora dienii, from the uppermost Cretaceous of southern Italy by Parente, reopened discussion of the genus. Subsequently, Barattolo attributed Salpingoporella turgida to Morelletpora, as Morelletpora turgida nov. comb., and considered the species as being “structurally similar to M. dienii”. Recent studies of Lower Cretaceous deposits from Iran revealed the existence of numerous, well-preserved specimens of Morelletpora turgida in the upper Barremian-Aptian Taft Formation of the Ardekan–Hersisht and Anarak areas of central Iran. These specimens allow a thorough morphological re-description of this alga and provide clear evidence for both the segmented character of the thallus and the characteristic shape of the laterals. These new data reinforce the assignment of this alga to Morelletpora, adding observations that support emendation of the diagnosis. Morelletpora turgida has been identified in limestones of Barremian-Cenomanian age from numerous regions representing the southern and central part of the Tethyan Domain.

Palynostratigraphy and paleobiogeography of the Jurassic – Lower Cretaceous succession in Kabrit-1 well, northeastern Egypt

Well-preserved and abundant Jurassic–Early Cretaceous palynomorph assemblages were recorded from the Kabrit-1 well, north Eastern Desert, Egypt. Thirty-one rock-cutting samples were analyzed and six rock units were differentiated. Seventy-one palynomorph species were identified from the productive samples. Six palynozones were differentiated, and they covered all the studied succession except for a palynomorph barren interval present in the uppermost part. These palynozones arranged in ascending order are as follows: two palynozones were recorded from the Middle-Upper Jurassic (Gonyaulacysta jurassica – Lithodinia jurassica Assemblage Zone and Klukisporites pseudoreticulatus- Systematophora penicillata – Escharisphaeridia pocockii Assemblage Zone) and the other four palynozones characterize the Lower Cretaceous deposits (Pilosisporites trichopapillosus – Cribroperidinium orthoceras Assemblage Zone; Dicheiropollis etruscus Interval Zone; Murospora florida – Afropollis operculatus Assemblage Zone and Afropollis jardinus Range Zone). We infer open marine conditions during deposition of the lower part of the Khalig El Ayoun Formation (Oxfordian-Kimmeridgian) and within the Kharita Formation (Albian), and shallow marine or coastal environments during deposition of the remainder of the studied succession. Paleobiogeographically, Late Jurassic index terrestrial palynomorph species documented here are in common with those previously recorded from North Africa, while marine dinocyst species are common to those documented from the West European and North American province. During the Early Cretaceous, the recorded terrestrial microfloral species were similar to those previously recorded from the West African-South American Province, while the marine dinocyst species were still related to the West European and North American marine palynofloral province.

Palynology of the Early Cretaceous Hanxia Section in the Jiuquan Basin, Northwest China: The discovery of diverse early angiosperm pollen and paleoclimatic significance

The Lower Cretaceous deposits of the Jiuquan Basin (Northwestern China) located in central Asia are famous for the abundant and diverse fossil products with distinct characteristics of Jehol Biota. However, few early angiosperm remains have been published in their entirety. This study presents a palynomorph record from the recently reported fossil-bearing Zhonggou Formation of the Hanxia Section in the Jiuquan Basin. Here, we first discovered abundant and diverse angiosperm pollen with 16 taxa, which can be classified into four morphological types: tricolpate, polyaperturate, monosulcate and etrachotomocolpate apertures. The palynomorph assemblages contain a large number of biostratigraphically significant palynomorphs, such as numerically abundant tricolpate and rare polyaperturate angiosperm pollen grains, which indicate an Early Albian age for the Zhonggou Formation of the Hanxia Section. The overall palynomorph assemblage is dominated by the Perinopollenites, followed by the Classopollis; bisaccate pollen indicate Taxodiaceae-dominant vegetation types. As such, a relatively temperate and humid climatic condition is suggested for this area. Furthermore, two palynomorph assemblages can be distinguished in a stratigraphically upward order with an obviously increasing Classopollis content, indicating a gradual aridification trend during the Early Albian. This climatic change may affect the diversification of early angiosperms based on the correlation with the stratigraphic distribution of discovered angiosperm pollen.

Cap-shaped gastropods from Upper Jurassic and Lower Cretaceous deposits of northern East Siberia

Cap-shaped gastropods are first identified in Upper Jurassic and Lower Cretaceous sections of northern East Siberia. They belong to three new genera of the subclass Pectinibranchia (Boreioconus gen. nov., Nixepileolus gen. nov., and Taimyroconus gen. nov.), which are identified at the species level (B. bojarkensis sp. nov., N. depressus sp. nov., T. zakharovi sp. nov.), and several species with the open nomenclature. The genus Taimyroconus attributed to the family Calyptraeidae is considered as an ancestral form of the genus Crepidula. The stratigraphic position of each taxon is determined for several sections. The facies confinement, habitat conditions, and ethology of defined genera are considered with the analysis of their geographic distribution.

Sedimentary Environment and Sequence Stratigraphy of the Lower Cretaceous Deposits in the Bideshk Area, at North of Esfahan, Iran

Background/Objectives: Rocks of the Mesozoic era in Iran, especially Cretaceous period, have been studied frequently from stratigraphic point of view, but little research has been done from sedimentology viewpoint. This study aims to restore the sedimentation condition and the conditions governing the sedimentary basins during that period (lower Cretaceous). Methods: One stratigraphic section was measured along the outcrop in Bideshk Area, at North of Esfahan. 63 thin sections samples were studied to determine the facies and a polarized microscope was used for the procedure. Findings: Based on lithological properties, 3 lithostratigraphic units have identified in the area. Facies analysis and field observations led to identification of 10 carbonate facies, 4 terrigenous facies and also 4 mixed (terrigenous and carbonate). Bideshk area was deposited on a homoclinal ramp setting within four zones including Continental, tidal flat, lagoon and bar environments. Sequence stratigraphic analysis identified three third-order depositional sequences in the studied area. Lower boundary in the first sequence is unconformity first-type boundary (SB1) (with Jurassic deposits) and consists of Transgressive Systems Tract (TST). Sequence number 2 consists of Low stand Systems Tract (LST), Transgressive Systems Tract (TST) and High stand Systems Tract (HST). Sequence 3 also consists of LST, TST and HST. Application: These results could be used for comparison with other worldwide localities and provide additional data for lower Cretaceous paleogeographic reconstructions.

Lower Cretaceous deposit reveals first evidence of a post-wildfire debris flow in the Kirkwood Formation, Algoa Basin, Eastern Cape, South Africa

The Algoa Basin is an onshore rift basin filled by an Upper Mesozoic non-marine and shallow marine sedimentary sequence. The middle unit of this clastic succession is assigned to the Lower Cretaceous Kirkwood Formation, known to host a wealth of plant and animal fossils together with poorly documented lignites, amber and charcoal clasts. This study is motivated by the growing interest in the impact of wildfires on the palaeoenvironment during the high-oxygen, Cretaceous world. It has been hypothesised that frequent and severe Cretaceous wildfires triggered large-scale non-marine denudation events, altering the sedimentation dynamics and influencing the evolution of ecosystems. In order to investigate this phenomenon, charcoal-bearing sedimentary rocks and plant fossil assemblages of the Kirkwood Formation have been studied at the Bezuidenhouts River locality, ∼50 km north of Port Elizabeth (Eastern Cape, South Africa).Detailed field observations of the sedimentary facies suggest that deposition occurred in a meandering fluvial environment with mature, vegetated floodplains. Depositional trends within a charcoal-rich bed (i.e., stratification, flattening and decrease in charcoal clast size down-current) indicate that a charcoal-rich debris flow, linked to a post-wildfire flood event, became diluted by fluvial flow. Palaeocurrent indicators (e.g., orientation of fossil logs) suggest unidirectional currents from SW to NE, which are somewhat inconsistent with the previously reported regional palaeocurrent directions in the Kirkwood Formation.To gain insights into the fire-influenced dynamics of the Early Cretaceous ecosystems, the macro-plant fossil assemblages of the Kirkwood Formation were considered, with reference to the responses of modern plant analogues to wildfire. Of the plant orders reported from macrofossils of the Kirkwood Formation, the Cycadales, Pinales and Filicales, are known to have produced large woody or fibrous trunks and stems, or in the case of the Bennettitales more densely branched, divaricate architectures, and are likely to have provided the bulk of fuel for wildfires, with fern elements dominating groundcover niches. The particular role of these plants in the Early Cretaceous wildfire palaeoecology of the Algoa Basin is a topic for an ongoing study, but the Bezuidenhouts River locality appears to record the aftermath of a severe crownfire that led to mass tree mortality.

Unusual deinonychosaurian track morphology (Velociraptorichnus zhangi n. ichnosp.) from the Lower Cretaceous Xiaoba Formation, Sichuan Province, China

A new Lower Cretaceous dinosaur footprint locality named the Mujiaowu tracksite in the Xiaoba Formation, Sichuan Province, has yielded a new assemblage containing the didactyl deinonychosaurian ichnogenus Velociraptorichnus. This is the eleventh report in the global record, the seventh from Asia and the fifth from China. All, except for an isolated report from Europe, occur in Lower Cretaceous deposits. Unlike previous reports of the ichnogenus, the Mujiaowu site has yielded both didactyl Velociraptorichnus tracks and tridactyl tracks which we interpret as a different expression of this same ichnogenus, caused by registration of digit II, either due to special substrate conditions or to less claw retraction. These tridactyl Velociraptorichnus footprints are assigned to the new ichnospecies Velociraptorichnus zhangi. Such tridactyl deinonychosaurid footprint morphology is predictable, but based on current ichnological evidence appears to be the exception rather than the rule.

A seismostratigraphic analysis of the lower cretaceous deposits of the Barents sea to reveal petroleum perspectives

The Lower Cretaceous deposits are the least studied interval of the section opened by drilling in the Barents Sea. Based on the principles of seismostratigraphy and sequence stratigraphy, the geological structure of the Lower Cretaceous deposits is studied. The distinguished complexes and sequences are considered as the main sedimentary complexes that formed at different stages of the regional geological evolution and, hence, possess different hydrocarbon prospects.

New Saldidae-Enicocorinae (Heteroptera: Leptopodomorpha) from the Lower Cretaceous of Siberia and Mongolia

Baissotea infanta gen. et sp. nov., B. peregrina sp. nov., and B. popovi sp. nov. from the Lower Cretaceous deposits of the Baisa locality, Eastern Siberia, and the Bon-Tsagan and Shin-Khuduk localities, Mongolia are described.

Mesozoic Diversity of Osmundaceae: Osmundacaulis whittlesii sp. nov. in the Early Cretaceous of Western Canada

Premise of research. A distinctive new species of osmundaceous fern, based on a permineralized trunk from Lower Cretaceous deposits of Haida Gwaii (formerly the Queen Charlotte Islands) off the west coast of mainland Canada, provides additional data for addressing the Mesozoic diversity and the overall pattern of phylogeny for osmundaceous filicalean ferns.Methodology. The specimen was cut into segments and studied from both external morphology and anatomical sections prepared by the cellulose acetate peel technique. Microscope slides of sections were examined, and images were captured under transmitted light.Pivotal results. The fossil represents a new species of Osmundacaulis, which is only the third Northern Hemisphere representative of this predominantly Southern Hemisphere genus.Conclusions. Osmundacaulis whittlesii sp. nov. increases the Northern Hemisphere diversity of Cretaceous Osmundaceae, thus providing new data about Mesozoic diversity of the clade, potential sister-group relationships of crown-group Osmundaceae, and the overall pattern of phylogeny for Osmundaceae.

Jurassic beaded lacewings (Insecta: Neuroptera: Berothidae) from Kazakhstan and Mongolia

Two new genera and four new species of Berothidae (Berothone gen. nov., Krokhathone parva gen. et sp. nov., K. tristis gen. et sp. nov., Sinosmylites karatavicus sp. nov., and S. auliensis sp. nov) are described from the Upper Jurassic of Karatau (Kazakhstan). Sinosmylites hotgoricus sp. nov. is described from the Upper Jurassic of Khoutiyn-Khotgor (Mongolia). Intraspecific variation of Jurassic berothids, quantitative composition of the berothid fauna of Karatau, and records of the family from Jurassic and Lower Cretaceous deposits are discussed.

Palynology of Aptian and upper Albian (Lower Cretaceous) amber-bearing outcrops of the southern margin of the Basque-Cantabrian basin (northern Spain)

The Lower Cretaceous deposits of the southern margin of the Basque-Cantabrian basin (northern Spain) are characterised by continental deposits interbedded with amber-bearing marine-influenced facies. These facies crop out in various localities and have yielded well-preserved palynological assemblages. The palynoflora is dominated by gymnosperm pollen grains, and shows relatively diversified spore content but scarce dinoflagellate cysts. The palynofloral evidence and regional geological setting indicate that the studied successions are dated as Aptian (Montoria-La Mina outcrop) and late Albian (Peñacerrada 1 and 2 and Salinillas de Buradón outcrops, and the Pancorbo site). Angiosperm pollen does not constitute a significant part of the Aptian assemblages but becomes diversified and numerically abundant in those dated as late Albian. Although broadly similar to contemporaneous palynofloras from eastern Spain, the Aptian assemblages of Montoria-La Mina do not yield tricolpate angiosperm pollen. Conversely, the inferred late Albian assemblages show a high content in polyaperturate angiosperm pollen grains, as occurs in other localities in Portugal, Western Europe and North America. The studied palynoflora shows significant differences from published assemblages located further north, in western France and Canada.

A review of large Cretaceous ornithopod tracks, with special reference to their ichnotaxonomy

Trackways of ornithopods are well-known from the Lower Cretaceous of Europe, North America, and East Asia. For historical reasons, most large ornithopod footprints are associated with the genus Iguanodon or, more generally, with the family Iguanodontidae. Moreover, this general category of footprints is considered to be sufficiently dominant at this time as to characterize a global Early Cretaceous biochron. However, six valid ornithopod ichnogenera have been named from the Cretaceous, including several that are represented by multiple ichnospecies: these are Amblydactylus (two ichnospecies); Caririchnium (four ichnospecies); Iguanodontipus, Ornithopodichnus originally named from Lower Cretaceous deposits and Hadrosauropodus (two ichnospecies); and Jiayinosauropus based on Upper Cretaceous tracks. It has recently been suggested that ornithopod ichnotaxonomy is oversplit and that Caririchnium is a senior subjective synonym of Hadrosauropodus and Amblydactylus is a senior subjective synonym of Iguanodontipus. Although it is agreed that many ornithopod tracks are difficult to differentiate, this proposed synonymy is questionable because it was not based on a detailed study of the holotypes, and did not consider all valid ornithopod ichnotaxa or the variation reported within the six named ichnogenera and 11 named ichnospecies reviewed here. We therefore emphasize the need to base comparisons between ichnotaxa on type material, and not on selected referred material. It is concluded that there is considerable variation in the morphology of the holotypes, as well as variation in size and quality of the samples and the mode of preservation. Conversely, there is considerable overlap in morphology among other tracks that have been informally attributed to these ichnotaxa. These factors make it difficult to synonymize any of the existing ichnotaxa without detailed revision of the samples from which the type material originates. Nevertheless, a review of the type material of all ichnotaxa is presented as a basis for further discussion and, as a first step, the ichnofamily Iguanodontipodidae is proposed to accommodate Amblydactylus, Caririchnium and Iguanodontipus.