Samuel Zamora

Instituto Geológico y Minero de España-CSIC

The Cambrian edrioasteroid “Totiglobus” spencensis Wen et al., 2019 is redescribed on the basis of a new and exquisitely preserved specimen from the Cambrian Wuliuan of the Spence Shale Member, Langston Formation (Utah). This new occurrence is associated with soft-body preservation of several invertebrate groups and other shelly fossils. The descri...

Jurassic cyrtocrinids from Spain are first documented here as representing relatively diverse from the western Tethys. The species Ascidicrinus pentagonus, Eugeniacrinites cariophilites, Gammarocrinites compressus, Pilocrinus moussoni, Sclerocrinus cf. S. strambergensis, and Tetracrinus moniliformis are described from Oxfordian marl levels belongin...

Los invertebrados representan más del 70% de la diversidad mundial y ocupan todos los ecosistemas conocidos. Esta diversidad es el resultado de más de 500 millones de años de historia evolutiva, cuando la mayoría de los principales grupos de animales aparecieron asociados a la Explosión Cámbrica de la vida. Conocer las relaciones evolutivas entre l...

The south-central margin of the Jaca Basin (South-central Pyrenees, Spain) offers well-exposed outcrops ideal for studying the distribution of decapod crustaceans across a mixed carbonate-siliciclastic depositional system during the middle-late Eocene (Bartonian-Priabonian). This study encompasses an area of 1000 km2, featuring environments from si...

Rhombifera bohemica Barrande is redescribed from Barrande’s original material and new specimens from Spain and the Czech Republic. Rhombifera had a heteromorphic proximal stem, a theca with three basals, three infralaterals and five laterals, both greatly elongated, but a reduced oral area in which five, facet-bearing radials alternate with five in...

Stalked crinoids were common in shallow-marine habitats in the geologic past but are today restricted to the deep sea. The timing of the shift in their bathymetric distribution has been discussed in the context of the Mesozoic Marine Revolution (MMR), one of the most important episodes of change in marine ecosystems of the Phanerozoic, which is gen...

Detailed facies and sequence stratigraphic analysis of an Aptian shallow-marine succession illustrates the evolution of sedimentary environments and their benthic faunal associations in a marginal bay developed in northeastern Iberia (Maestrazgo Basin, Oliete Subbasin). In this bay, marine circulation was hampered by wide stationary shoals located...

Echinoderms are a major group (phylum) of invertebrate animals with a rich fossil record stretching back to the Cambrian period, approximately 518 million years ago. While all modern species are characterized by pentaradial (i.e., fivefold) symmetry, Cambrian echinoderms also include taxa with different types of symmetry (e.g., bilateral symmetry)....

La paleontología ha contribuido de manera decisiva a responder algunas de las cuestiones más relevantes de las ciencias de la Tierra. Muchos paradigmas que hoy damos por ciertos, como los cambios significativos de la atmósfera, la deriva de los continentes o la evolución de los seres vivos y sus eventos de extinción en masa, están en parte fundamen...

The transition from sessile suspension to active mobile detritus feeding in early echinoderms (c.a. 500 Mya) required sophisticated locomotion strategies. However, understanding locomotion adopted by extinct animals in the absence of trace fossils and modern analogues is extremely challenging. Here, we develop a biomimetic soft robot testbed with a...

Deposits preserving non-biomineralized tissues and animalsprovide an unrivalled opportunity to study the evolution andradiation of early animal life. Numerous sites of Cambrian ageare known from North America (Laurentia) and South China(East Gondwana), which provide a high resolution pictureof the fauna at low latitudes. By contrast, our knowledge...

In the Lower Ordovician of Morocco, solutan echinoderms are relatively common, locally abundant, geographically widespread (Central and Eastern Anti-Atlas), and biostratigraphically long-ranging (late Tremadocian–mid Floian) components of the Fezouata Biota. The lower part of the Fezouata Shale (late Tremadocian) yielded one specimen, here tentativ...

Decapod crustaceans are an important component in modern ecosystems with a rich fossil record spanning more than 400 million years. Last summer (19th–24th June 2022) the 8th Symposium on Fossil Decapod Crustaceans took place in Zaragoza (Spain), a meeting covering all aspects of studies on fossil decapod crustaceans, including information from mode...

Eubrachyurans, or ‘higher’ true crabs, are the most speciose group of decapod crustaceans and have a rich fossil record extending into the Early Cretaceous. However, most extant families are first found in the fossil record in the Palaeogene, and particularly in the Eocene. Unfortunately, fossils of many early eubrachyuran groups are often fragment...

The sequence stratigraphy and palaeogeographical evolution of an Aptian shallow-marine bay in the Western Tethys has been reconstructed through detailed analysis and correlation of 10 bed-by-bed logs spanning the Aptian stratigraphic record of the Oliete subbasin (Maestrazgo Basin, Eastern Iberia). Three third-order transgressive–regressive (T–R) s...

Decapod crustaceans are rare in Early Cretaceous invertebrate assemblages from the Iberian Peninsula; however, current knowledge does allow differences in taxonomic composition between different basins and subbasins to be recognised. In order to understand the distribution of Barremian–Aptian decapod crustaceans of Iberia better, seven new localiti...

Asturicystis' havliceki Fatka & Kordule from the middle Cambrian of Bohemia (Czech Republic) is re-described based on its type material. Several features, including the extension of the food grooves and presence of ventral swellings suggest that 'A.' havliceki does not belong to Asturicystis, and is placed in the new genus Bohemiacinctus. To ascert...

2023. Filling the Silurian gap of solutan echinoderms with the description of new species of Dehmicystis from Spain. Acta Palaeontologica Polonica 68 (2): 185-192. Solutans were among the most enigmatic pre-radial and asymmetric echinoderms. A new species Dehmicystis ariasi sp. nov. is described from the upper part of the Llagarinos Formation, lowe...

The origin and function of peculiar mushroom-shaped cuticular structures in some decapod crustaceans remains unknown. This ornamentation has appeared several times in widely disparate clades (in podotreme and heterotreme crabs, and pagurids). These structures are analysed in the modern genus Daira and compared with fossil material from the Eocene o...

Until now, the earliest fossil echinoderms have been predominantly known from the early Cambrian of Laurentia and West Gondwana. Here, we describe Sprinkleoglobus extenuatus gen. et sp. nov. from the Chengjiang biota (Cambrian Series 2, Stage 3) of Yunnan Province, China. The overall profile of the theca and the morphology of the ambulacra clearly...

A highly diversified fauna of hermit crabs associated with reef environments from the Serraduy Formation (lower Eocene) in the southern Pyrenees (Huesca, Spain) is described. Other European Eocene outcrops have yielded paguroids associated with a single environment; however, the studied association represents one of the highest paguroid diversities...

The sequence stratigraphy and palaeogeographical evolution of an Aptian shallow-marine ramp, developed in a shallow marine bay in the Western Tethys, has been reconstructed through detailed analysis and correlation of 10 high-resolution logs spanning the Forcall and Oliete formations of the Oliete subbasin (Maestrazgo Basin, Eastern Iberia). Tow lo...

A new echinoid belonging to the genus Habanaster is described from the Western Pyrenees (Pamplona basin, Spain). Definition of Habanaster itzae nov. sp. is based on 16 well-preserved specimens that were collected from Lutetian levels (middle Eocene) of the Anotz Formation. These levels have been interpreted as deposited in low energy, hemipelagic c...

http://deepblue.lib.umich.edu/bitstream/2027.42/172912/2/Contributions 34 - Baumiller Sp. Volume Lo Res.pdf

About 40 million years after the Cambrian Explosion, the Great Ordovician Biodiversification Event (GOBE) represents a second and dramatic burst in marine biodiversity, with major changes in the structure of ecosystems and the progressive replacement of the distinctive Cambrian Evolutionary Fauna by the Paleozoic Evolutionary Fauna. However, the GO...

The Roda Formation (early Eocene Ypresian, Huesca, Aragón, northern Spain) records successive levels including rich decapod faunas relevant for the understanding of Ypresian decapod assemblages. Asthenognathus fernandezin. sp. is described from one of these levels, representing the oldest report of a fossil Asthenognathinae, and the first report fr...

Millericrinids constitute an order of extinct articulate crinoids that range from the Middle Triassic to the Late Cretaceous. Based on partially articulated material comprising calyces, columns, and holdfasts, six species (one of them new) belonging to five different genera are described from the Late Jurassic of Spain for the first time. They incl...

The exquisitely preserved, diverse and abundant fossil assemblages yielded by the ‘echinoderm meadows’ of the Tafilalt region of the eastern Anti-Atlas represent a new Konservat-Lagerstätte, one of the few exceptionally preserved Late Ordovician open marine faunas found globally, giving us an insight into the radiation of life during the later phas...

Echinoderms are characterized by a distinctive high-magnesium calcite endoskeleton as adults, but elements of this have been drastically reduced in some groups. Herein, we describe a new pentaradial echinoderm, Yorkicystis haefneri n. gen. n. sp., which provides, to our knowledge, the oldest evidence of secondary non-mineralization of the echinoder...

The extensive, predominantly siliciclastic deposits of the Upper Ordovician of the Tafilalt have long been the subject of scientific investigation. In the past 25 years, intensified collecting for commercial purposes has resulted in the discovery of several exceptionally-preserved faunas ( Konservat-Lagerstätten ) in the Tafilalt region, preserving...

In this paper, we analyse the upper Barremian-lowermost Aptian Alacón Formation (Oliete subbasin, Maestrazgo Basin) of Spain to understand the progressive opening of a shallow-marine bay found on the northeastern margin of Iberia. The succession consists of four transgressive-regressive sequences (S1S4) bounded by widespread unconformities caused b...

A B S T R A C T The cyrtocrinid crinoid Proholopus holopiformis (Remeš, 1902) is described from the upper Albian succession that may be included in the Albeniz unit to the east of Iruñea-Pamplona (Navarre, Western Pyrenees, Spain). Although based on partially disarticulated material, this taxon preserve calyx, stem, attachment structure, and brachi...

A highly diverse fauna of dromioid brachyurans from the Serraduy Formation (lower Eocene) in the western Pyrenees (Huesca, Spain) is described and illustrated. Recorded taxa are Mclaynotopus longispinosus new genus new species, Torodromia elongata n. gen. n. sp., Basidromilites glaessneri n. gen. n. sp., ? Basidromilites sp., Sierradromia gladiator...

A new genus and two new species of fossil hermit crabs (Anomura, Paguroidea) are described from the southern Pyrenean basins (Huesca, NE Spain). Parapetrochirus nov. with P. robustus n. gen., n. sp., as type species, comes from the lower Eocene (Ypresian) Roda Formation. It preserves both chelipeds exhibiting a notable heterochely, a larger left ch...

The Sobrarbe-Pirineos UNESCO Global Geopark, located in the Central Pyrenees, is a region of remarkable geodiversity that includes extensive Eocene fossil-bearing sites and constitutes an important archive of paleobiodiversity. The Sobrarbe-Piri-neos Geopark hosts outcrops of Eocene formations bearing an unusual abundance and diversity of fossils f...

Se presenta el análisis secuencial y de facies de las formaciones Alacón, Forcall y Oliete, que conforman el registro marino del intervalo Barremiense superior-Aptiense en la subcuenca de Oliete (Cuenca del Maestrazgo). El estudio y correlación de diez perfiles levantados capa a capa ha permitido identificar tres grandes ciclos transgresivo-regresi...

The progressive opening of an Early Cretaceous (late Barremian-earliest Aptian) shallow marine bay has been reconstructed through the analysis and correlation of 10 high-resolution logs in the Oliete subbasin, a 30x30 km area subdivision of the Maestrazgo Basin (Teruel, NE Spain). The studied stratigraphic series corresponds to the Alacón Formation...

Modern reefs are considered important hot spots of biodiversity, but the analysis of the distribution of the invertebrate fauna across different reefal domains in ancient ecosystems can be challenging, because the fossil record is usually affected by strong taphonomic biases. The lower Eocene coral reef in the well-exposed outcrops of Ramals (Tremp...

A b s t r a c t Decapod crustaceans from the Forcall Formation (Aptian, Lower Cretaceous) of the Oliete Sub-basin (Maestrazgo Basin) are recorded, specimens having been collected from the localities of Josa and Obón (Teruel) in the Aragonese branch of the Iberian Cordillera, northeast Spain. The glypheid lobster Atherfieldastacus magnus is by far t...

Semi-articulated paguroids are rare fossils, and there are only few records from Cenozoic strata. Here we present a new and exceptionally preserved hermit crab (Diogenidae) from the Eocene of Huesca (Spain) that preserves the anterior part of the carapace, together with appendages. Diogenes augustinus sp. nov. represents one of most completely pres...

Reconstructing the function and behaviour of extinct groups of echinoderms is problematic because there are no modern analogues for their aberrant body plans. Cinctans, an enigmatic group of Cambrian echinoderms, exemplify this problem: their asymmetrical body plan differentiates them from all living species. Here, we used computational fluid dynam...

A new decapod crustacean assemblage associated with late Eocene coral reef deposits in northeast Spain (southern Pyrenees) is recorded; it includes Gemmellarocarcinus riglosensis sp. nov., Daira corallina sp. nov., Lobogalenopsis joei sp. nov., Liopsalis cf. anodon (Bittner, 1875) and Gale nopsis crassifrons A. Milne-Edwards, 1865. The genera Gemme...

A new exceptionally-preserved Cambrian biota, with fossils belonging to multiple phyla, has recently been found from the middle part of the Longha Formation, near Fulu Village, southeastern Yunnan, South China, and is named the Fulu biota. Groups recovered so far include polymerid trilobites, agnostoids, large bivalved arthropods, bradoriid arthrop...

Quantifying morphological evolution is key to determining the patterns and processes underlying the origin of phyla. We constructed a hierarchical morphological character matrix to characterize the radiation and establishment of echinoderm body plans during the early Paleozoic. This showed that subphylum-level clades diverged gradually through the...

A new exceptionally-preserved Cambrian biota, with fossils belonging to multiple phyla, has recently been found from the middle part of the Longha Formation, near Fulu Village, southeastern Yunnan, South China, and is named the Fulu biota. Groups recovered so far include polymerid trilobites, agnostoids, large bivalved arthropods, bradoriid arthrop...

Featherstars, comatulid crinoids that shed their stalk during their ontogeny, are the most species‐rich lineage of modern crinoids and the only ones present in shallow water today. Although they are of considerable palaeontological interest as a ‘success story’ of the Mesozoic Marine Revolution, their fossil record is relatively species‐poor and fr...

Rhenopyrgids are rare, turreted edrioasterid edrioasteroids from the lower Paleozoic with a distinctive and apparently conservative morphology. However, new, well-preserved rhenopyrgid edrioasteroid material from Canada, along with a review of described taxa, has revealed broader structural diversity in the oral surface and enabled a re-evaluation...

The Anti-Atlas contains a thick, volcanic-free Ordovician succession that originally deposited in a passive-margin basin. Three main sedimentary packages are bounded by major unconformities: (i) the Tremadocian–Floian Lower Fezouata and Upper Fezouata formations, which unconformably overlie a palaeorelief of Cambrian rifting volcanosedimentary comp...

Progressive opening of the Rheic Ocean led to the drifting away of one or several ribbon terranes, generally ascribed to Avalonia, and inaugurated a passive margin stage on the newly formed margin of NW Gondwana. In Iberia, which remained on the Gondwanan side of the ocean, the rift to drift transition is recorded in the Ossa Morena Zone in latest...

A new Lower Devonian fauna from the Iberian Chains (NE Spain) is described. Specimens have been collected from the shaley intervals of the Mariposas Formation dated as early Emsian. These include the camerates Acanthocrinus carsli n. sp., Platyhexacrinus santacruzensis n. sp., Culicocrinus breimeri n. sp., Camerata indeterminate, and an indetermina...

A taxonomic study of the trilobites found in the Marianian parastratotype of the Iberian Chains, north‐east Spain, results in the recognition of the new redlichiid Redlichia isuelaensis sp. nov., the ellipsocephalid Lusatiops ribotanus, and the saukiandids Onaraspis garciae sp. nov., Paulaspis tiergaensis gen. et sp. nov. and Luciaspis matiasi gen....

We describe Aragolambrus collinsin. gen., n. sp. from the Eocene (Ypresian) of Huesca, Aragón, northern Spain, which represents the second report of a fossil Parthenopidae from Spain and the first from the Eocene. Aragolambrus collinsin. gen. n. sp. is considered one of the oldest parthenopid crabs, and important morphological features include the...

Hexedriocystis is a very unusual echinoderm with a puzzling combination of morphological features. The two described species H. inexpectatus and H. mimus occur in Upper Ordovician siliciclastic rocks from Morocco, North Africa. They show a striking combination of isorophid edrioasteroid, paedomorphic crinoid and blastozoan characteristics including...

New Upper Ordovician Echinoderm–Lagerstätten from the Anti-Atlas of Morocco have provided large collections of blastozoan echinoderms. The echinosphaeritid Echinosphaerites dianae n. sp. preserves the oral region, stem and brachioles, characteristics absent in many species of the same genus. Homocystites adidiensis n. sp. is represented by almost 5...

Repaired fossil skeletons provide the opportunity to study predation rates, repair mechanisms, and ecological interactions in deep time. Trilobites allow the study of repaired damage over long time periods and large geographic areas due to their longevity as a group, global distribution, and well-preserved mineralized exoskeletons. Repair frequenci...

Latest findings on our study about the evolution of pentaradiality in echinoderms, presented in a poster here.

Los paleontólogos investigadores han utilizado el epíteto latinizado aragonensis o aragonense para nombrar a cuarenta (40) de las mil diez (1010) especies de fósiles que han descrito por primera vez en territorio aragonés. De forma similar, han utilizado en doce (12) ocasiones un lexema que se refiere a Aragón o a alguna cuestión relacionada con Ar...

Post-Palaeozoic crinoids from northeast Spain ranging from the Ladinian (Middle Triassic) to the Ilerdian (lower Ypresian, early Eocene) are documented. Here we provide the first attempt to reconstruct the environmental distribution of these crinoids based on relatively complete material (mostly cups). Triassic forms are dominated by encrinids from...

Coronates are widely distributed in Ordovician and Silurian rocks from Gondwana but have never been reported from Africa. A single theca of Mespilocystites sp. is the first representative of this blastozoan clade from the African continent, extending its geographical range. Previous reports of Mespilocystites include the Czech Republic, France, Ita...

Edrioasteroids from the Katian, Lower Ktaoua and Upper Tiouririne formations provide new data on several previously described species and two new species of edrioasteroids. Ontogenetic and palaeoecological data are provided for Moroccopyrgus matacarros . Well-preserved oral areas and internal views of the oral frame show Euryeschatia reboulorum to...

A new brachiopod species, Westonia mardini, from the Furongian of Turkey and a new occurrence of Westonia urbiona from the Cambrian Series 3 of Iberian Peninsula are reported. These new finds of ‘westoniids’ collected in Gondwana allow the discussion of the functional morphology of their terrace ridges. This structure enabled an effective and rapid...