De Lapparent Research Articles

Late Cretaceous Planktonic Foraminifera of the Mountainous Crimea in the MSU Earth Science Museum’s Collection

Planktonic foraminifers are widely distributed in the Upper Cretaceous deposits of the Mountainous Crimea. Marker species are of great importance for biostratigraphy and section correlation. Tests Globotruncanita stuarti (De Lapparent, 1918) and Pseudotextularia elegans (Rzehak, 1891) are used as index species for local and regional biostratigraphic scales, and tests of the genus Rugoglobigerina Brönnimann, 1952 are for the faunal layers. The article provides a systematic description of important biostratigraphic species Pseudotextularia elegans (Rzehak, 1891), Rugoglobigerina rugosa (Plummer, 1927), R. hexacamerata Brönnimann, 1952, R. milamensis Smith and Pessagno, 1973, R. macrocephala Brönnimann, 1952 и Globotruncanita stuarti (De Lapparent, 1918), on the basis of which the age of the rocks of five sections of the Mountainous Crimea was determined.

« Science et fiction », un projet interdisciplinaire novateur en collège au regard des œuvres de Jules Verne et d'Albert de Lapparent

Les pages qui suivent rendent compte d’une expérience pédagogique menée durant les années scolaires 2019 à 2021, sous la forme d’un Enseignement Pratique en Interdisciplinarité (EPI). Le projet s’inscrit dans une réflexion sur l’accès au savoir de manière générale, et spécifiquement à la connaissance scientifique. Dans le cadre du sesquicentenaire de la Société Géologique du Nord, et en conformité avec les programmes scolaires, une équipe d’enseignants de disciplines à première vue éloignées mais pourtant si proches, a travaillé avec deux classes de 3e, en collaboration avec le Musée d’Histoire Naturelle de Lille et l’Université des Sciences de Lille. Deux textes ont été proposés à l’étude : Voyage au centre de la Terre de Jules Verne, publié en 1864, et La question du charbon de terre d’Albert De Lapparent en 1890. L’enseignement en interdisciplinarité (Sciences de la Vie et de la Terre SVT, Français, Technologie et Histoire-Géographie-Enseignement Moral et Civique EMC) avait notamment pour objectif de faire comprendre aux élèves que la connaissance scientifique ne se réduit pas aux spécialistes qui en font leur domaine de réflexion ou d’application mais, au contraire, que la diffusion des connaissances scientifiques ainsi que le débat scientifique nous concernent tous. À l’époque de J. Verne, la littérature destinée à la jeunesse se donne pour mission d’instruire autant que de divertir. L’auteur diffuse, expose des savoirs : en géologie et minéralogie, mais aussi en géographie et en histoire. Il permet au lecteur d'aller à la rencontre des connaissances, de les expérimenter sous la forme de l'aventure. Afin de rendre compte du parcours muséal des personnages verniens, les élèves ont réalisé la programmation d’une application pour tablette qui prend la forme d’un « Musée virtuel », à partir du logiciel APP INVENTOR©. Le visiteur peut découvrir le texte du romancier, agrémenté de lectures à voix haute, mais aussi de connaissances scientifiques acquises grâce à l’étude des deux textes et à des rencontres avec des spécialistes extérieurs à l’établissement. Les élèves sont ainsi devenus des passeurs de science et de littérature. Comme J. Verne, ils rapportent des savoirs et exposent ce qui n’est pas encore montré. Dans l’application sont intégrées des reconstitutions paléoenvironnementales des passages de l’œuvre (Carbonifère, Jurassique), des approches scientifiques de processus géologiques et biologiques (minéralogie, volcanisme, paléontologie, évolution des organismes vivants dont la phylogénie des Primates et donc de l’Homme). De plus, J. Verne prédit déjà la fin de l’exploitation minière, thèse reprise par A. De Lapparent quelques années plus tard en 1890 dans son écrit scientifique. Une des salles de ce musée virtuel est consacrée à l’époque carbonifère. Une réécriture de l’expédition dans la houillère y est présentée ainsi que la reconstitution de l’histoire géologique et une réflexion économico-historico-environnementale comparant l’exploitation de la ressource fossile du XIXe siècle à nos jours.

Late-latest Maastrichtian foraminiferal assemblage from the Angostura Platform, Chiapas, SE Mexico: Biostratigraphic, paleoenvironmental and paleobiogeographic significance

The carbonate platform deposits of the Angostura Formation are widely distributed in the central and eastern part of the Sierra de Chiapas, SE Mexico. The Angostura Formation contains a rich assemblage of foraminifera associated with mollusks (rudists, gastropods), corals, and dasycladacean green algae.A detailed foraminiferal study was carried out on samples from the El Coyol section of the Angostura succession. The studied section crops out in the El Coyol Hacienda located north of the Angostura dam, SE of the city of Tuxtla Gutiérrez in Central Chiapas. The foraminiferal assemblage consists mostly of benthic larger foraminifera but minor pelagic influence is represented by the presence of a number of planktic foraminifera.The benthic foraminiferal association is taxonomically diverse, being composed of Chubbina jamaicensis Robinson, Chubbina macgillavry Robinson, Caribealveolina michaudi Pêcheux, C. fourcadei Vicedo, Caus and Frijia, C. obesa (Fourcade and Fleury), Praechubbina breviclaustra Fourcade and Fleury, Omphalocyclus macroporus (Lamarck), Asterorbis rooki Vaughan and Cole, Vaughanina cubensis (Palmer), V. barkeri, Brönnimann, Sulcoperculina dickersoni (Palmer), S. globosa de Cizancourt, S. vermunti (Thiadens), Lepidorbitoides minima Douvillé, Orbitoides cf. O. apiculata Schlumberger, Planorbulina cretae (Marsson), Smoutina cruysi Drooger, and Nezzazatinella sp. In addition, the occurrence of Fleuryana adriatica De Castro, Drobne and Gušić, Rhapydionina cf. R. liburnica Stache, Cuneolina ketini Inan, Valvulina cf. V. triangularis d'Orbigny and Minouxia sp. is documented for the first time from the Angostura Formation.The planktic foraminifera are Rugoglobigerina macrocephala Brönnimann, R. cf. R. hexacamerata Brönnimann, R. rugosa (Plummer), Kuglerina rotundata (Brönnimmann), Muricohedbergella monmouthensis (Olson), Planoglobulina cf. P. carseyae (Plummer), Globotruncanita stuarti (de Lapparent), Globotruncanita pettersi (Gandolfi), Planoheterohelix globulosa (Ehrenberg), Pseudoguembelina sp., Macroglobigerinelloides prairielillensis (Pessagno) and the pithonellids Pithonella ovalis (Kaufmann) and P. sphaerica (Kaufmann). The age of the Angostura Formation in the studied section is late to latest Maastrichtian. A Chubbina jamaicensis Taxon Range Zone is proposed on the basis of the occurrence of the nominal taxon and foraminiferal association.The lithological and faunal evidence enable the paleoenvironment to be reconstructed. The microfacies (wackestone–packstone, wackestone–floatstone, wackestone, grainstone and packstone) as well as the foraminiferal assemblage suggest that the deposit was developed in a shallow water marine setting with low to moderate energy, with sporadic intercropping of an open platform deposit characterized by planktic foraminifera and pithonellids.The paleobiogeographical distribution of the foraminiferal association from the Angostura Formation contains cosmopolitan genera as well as endemic forms of the Caribbean Province from the Tethys Realm.

Evidence for a pre-PETM dispersal of the earliest European crocodyloids

Crocodyloid remains from the late Paleocene of Mont de Berru (France) hosted in the collections of the Muséum National d’Histoire Naturelle (Paris, France) and in the Institut royal des Sciences naturelles de Belgique (Brussels, Belgium) are described for the first time. This material, although fragmentary, can be clearly referred on a morphological basis to Asiatosuchus depressifrons (Blainville, 1855), a species previously reported from several Eocene Belgian localities thanks to abundant material including a nearly complete skeleton. The Paleocene material shares with A. depressifrons the number of alveoli involved in the dentary symphysis, the exclusion of the splenials from the symphysis, and the presence of a distinct depression on the jugal. The fossil remains from Berru represent the oldest European crocodyloid. Along with the alligatoroid Diplocynodon remensis Martin, Smith, de Lapparent de Broin, Escuillié and Delfino, 2014, previously reported from the same locality, the crocodyloid A. depressifrons indicates that these genera reached Europe before the Paleocene–Eocene Thermal Maximum. Although more complete remains from outside Europe are needed to refine phylogenetic hypotheses, according to the currently established fossil record the forerunners of diplocynodontids likely dispersed from North America, whereas those related to Asiatosuchus likely dispersed from Asia.

Systematic study of the historical material of Upper Cretaceous reptiles from the Tremp Basin (Catalonia, Spain) housed at the Museo Nacional de Ciencias Naturales (Madrid)

Purpose The development of the studies on Mesozoic reptiles of the Spanish record occurred much later than in several European countries such as United Kingdom, France or Germany. Thus, very scarce and punctual findings were performed in the second half of the 19th century, followed by the work of Jose Royo y Gomez, which was stopped by the Spanish Civil War. The professional surveys and studies carried out in the 1950s in the Upper Cretaceous levels of the Tremp Basin (Lleida, Catalonia, Spain) can be considered as the origins of the development of this discipline in Spain. The works in the Tremp Basin were performed through the collaboration of national and foreign researchers. The Spanish palaeontologist Emiliano Aguirre and the French Albert Felix de Lapparent published some preliminary notes on the vertebrate fauna identified there. However, no detailed systematic study of these historical remains was ever done.

A miniature notosuchian with multicuspid teeth from the Cretaceous of Morocco

ABSTRACTNotosuchians from Cretaceous continental environments of Gondwana have developed an unexpected array of morphologies comparable to mammals and their extinct relatives. However, this exceptional diversity is unbalanced, with South America holding nearly three times the generic diversity of Africa-Madagascar. With the exception of the triconodonts and of a very specialized group, the Gondwanatheria, in none of these landmasses do mammals dominate, and as a result, the low notosuchian diversity in Africa-Madagascar appears to be an artifact of sampling. Here, we describe a new miniature notosuchian from the Albian-Cenomanian Kem-Kem Beds of Morocco filling this gap. Lavocatchampsa sigogneaurussellae, gen. et sp. nov., exhibits a new type of heterodonty with absence of maxillary and dentary caniniform dentitions and teeth that gradually become massive posteriorly, and possess a sharp elongate median carina flanked by two multicusped cingula. The occlusion pattern is revealed by computed tomography and scanning electron microscopy (SEM) and shows that the main component of jaw closure is vertical, and not horizontal as has been proposed in closely related forms. Phylogenetic analysis recovers the new taxon as part of a basal stock of Gondwanan ziphosuchians with close affinities to Candidodon itapecuruense, Malawisuchus mwakasyungutiensis, and Pakasuchus kapilimai. We revise the diagnosis of Candidodontidae, a clade characterized by a particular heterodont dentition recalling that of triconodont mammals. The recognition of this new clade confirms previous hypotheses of a vicariant vertebrate assemblage present on a continuous South American–African landmass.http://zoobank.org/urn:lsid:zoobank.org:pub:0D35356B-67FF-49A2-A518-6C19961A0894SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/ujvpCitation for this article: Martin, J. E., and F. de Lapparent de Broin. 2016. A miniature notosuchian with multicuspid teeth from the Cretaceous of Morocco. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1211534.

Revision and phylogenetic affinities ofElosuchus(Crocodyliformes)

Elosuchidae is a clade of longirostrine Crocodyliformes currently confined to Barremian through Cenomanian deposits in north-west Africa and Great Britain. The clade is currently composed of Elosuchus cherifiensis (Lavocat, 1955), Elosuchus felixi de Lapparent de Broin, 2002, Sarcosuchus imperator Broin & Taquet, 1966, Sarcosuchus hartii Buffetaut & Taquet, 1977, Vectisuchus leptognathus Buffetaut & Hutt, 1980 and, by some authors, Stolokrosuchus lapparenti Larsson & Gado, 2000. We redescribe Elosuchus from assigned and new material. This genus occurs in terrestrial Cenomanian deposits in Morocco and Algeria and known from multiple relatively complete skulls. The holotype is unknown but the assigned lectotype in the Museum National d'Histoire Naturelle (Paris, France) is composed of a fragmentary ventral braincase. Referred paralectotype material housed in the same museum includes multiple fragmentary specimens and two nearly complete skulls. These and additional material in the Canadian Museum of Nature and Royal Ontario Museum were used to re-examine the genus. The original and new material show a number of autapomorphies among crocodyliforms: a unique contribution of the squamosal and jugal to the postorbital anterolateral process and a highly modified suborbital fenestra that displaces the antorbital cavity anteriorly and forms a bony wall separating the cavity from the orbit. Two diagnosable morphotypes are revealed, one from the Kem Kem beds, Morocco, and the other from Gara Samani, Algeria. We retain Elosuchus cherifiensis for the Kem Kem form and erect a new species Elosuchus broinae sp. nov. for the Algerian form. The revised diagnosis for Elosuchus questions the validity of E. felixi. Elosuchus is incorporated into a phylogenetic analysis that includes extensive revisions to character scores for relevant taxa. The resulting topologies recover Elosuchus sister to Meridiosaurus vallisparidisi Mones, 1980, within a complex of ‘Pholidosauridae’ that includes elosuchids and dyrosaurids but excludes Stolokrosuchus. This phylogenetic revision is used to discuss the evolution of this clade and its contribution to crocodyliform diversity during the Cretaceous.

Du crocodile d’Aoulef au Sarcosuchus imperator

This paper is a tribute to my colleague and friend France de Lapparent; it recounts briefly all the stages of a nice paleontological discovery, which began in Algeria in 1947, when the geologist Albert-Felix de Lapparent collected fragments of a crocodile of massive size in Lower Cretaceous sediments. The study of these fragments by France de Lapparent, and the subsequent discovery in Niger of a skull and elements of the skeleton of a crocodile of the same species by the author of these lines, led us together to describe and to name this monster Sarcosuchus imperator, which is today famous under the nickname Supercroc.

France de Lapparent de Broin: Specialist of turtles and crocodiles

France de Lapparent de Broin is an expert on extinct crocodiles and turtles who has made them known to the paleoherpetological community over almost 50years. Her studies have dealt with fossils from the Mesozoic (mostly the Cretaceous) and the Cenozoic (mainly the Eocene and Miocene). She has been interested in faunas originating mainly from Europe, Africa and South America, and she produced large reviews of turtles from these continents. She erected several taxa, mostly of turtles. Among these taxa are some strange forms that appear to represent unique morphological types.

Geology meets archaeology: rediscovering the life and work of Geoffroy d’Ault du Mesnil (1842–1921)

The period between the middle of the nineteenth century and the beginning of the twentieth century saw the birth and consolidation of prehistory and archaeology as scientific disciplines. Discussions of method and theory were posed; the antiquity of humankind was demonstrated; stratigraphic and chrono-typological sequences were settled. This process was initially linked to the natural and geological sciences. In France the names of J. Boucher de Perthes, E. Lartet, A. de Lapparent, E. Piette, E. Cartailhac, G. de Mortillet, L. Capitan and H. Breuil appeared; their role in the development of research frameworks at the national, European and international scales is well known, and they have been the subject of detailed studies in the historiography of geology and/or archaeology. However, the name of one of the most influential characters of the period seems to have been forgotten. This paper attempts to reassess the scientific standing and explore the personal life of Geoffroy d’Ault du Mesnil (1842–1921) through first-hand analysis of a variety of sources. The paper analyses the origins of his interdisciplinary approach to science, how he came to be a leading expert on the Quaternary terraces of the valley of the Somme and his key role in research on, and the preservation of, France's prehistoric heritage. This ultimately permits a renewed understanding of d’Ault du Mesnil's contribution to the scientific development of geology and prehistory, in addition to demonstrating how the wider social, economic and political context of the time shaped his own scientific personality.

Discovery and study of dinosaurs from Spain: The contribution of Albert F. de Lapparent

Albert F. de Lapparent (1905–1975), the scion of a family of famous French geologists, was a dinosaur palaeontologist. He explored many territories in Europe, Saharan Africa and Asia in search of fossils. The studies he undertook in Spain, which resulted in a dozen publications between 1955 and 1969, are an important part of his research on dinosaurs. Lapparent et al. discovered about thirty dinosaur localities, mostly of Cretaceous age, in several Spanish provinces, including Albacete, Castellón, Cuenca, Soria, Teruel and Valencia in the Iberian Range, and Lleida (or Lérida) in the Pyrenean region. In 1958, Lapparent published the discovery of dinosaur eggs in the Tremp Basin (Lleida), the first ones found in the Iberian Peninsula. His 1960 work on the dinosaurs of Galve (Teruel) was the first monograph on the subject published in Spain. In 1965, Lapparent was also the first to publish the discovery of dinosaur footprints in Spain, more specifically in the province of Valencia.

Morphological Abnormalities and Dwarfism in Maastrichtian Foraminifera from the Cárdenas Formation, Valles–San Luis Potosí Platform, Mexico: evidence of paleoenvironmental stress

During the early Maastrichtian an assemblage rich in large foraminifera, mostly composed of orbitoidal foraminifera, developed in the shallow-water deposits of the Cardenas Formation (Valles–San Luis Potosi Platform, Mexico). Among them, the most abundant is Lepidorbitoides minima, some of which display a morphologically abnormal test consisting of polyvalent forms, conical tests and budding, which could be induced by abrupt changes in environmental factors. The occurrence of the abnormalities preceded the demise of this species and of all the larger foraminiferal association in the upper part of the Gansserina gansseri Zone (early Maastrichtian). The abnormalities could be induced by environmental stress, probably related to interplay of different events such as increased terrigenous input and the transition to deeper facies due to Laramide tectonic instability before the K/P boundary. A late Maastrichtian community of dwarfed planktic foraminifera composed of Trinitella scotti Bronnimann, Plummerita reicheli Bronnimann, Rugoglobigerina cf. macrocephala Bronnimann, Rugoglobigerina hexacamerata Bronnimann, Heterohelix punctulata (Cushman), Pseudoguembelina costulata (Cushman), Pseudotextularia intermedia de Klasz, Globigerinelloides asperus Bolli, Guembelitria cretacea Cushman, Rugoglobigerina rugosa (Plummer), Rugotruncana sp., Globotruncanita stuarti (de Lapparent), and Globotruncana arca (Cushman) developed in the upper part of the sequence. This uncommon morphology could also be related to the highly stressed paleoenvironmental conditions related to global climatic change and local tectonic activity. Associated with this planktic assemblage is a deeper-water dwarfed benthic foraminiferal community composed of Gyroidinoides nitidus (Reuss), Coryphostoma incrassata (Reuss), Pseudouvigerina plummerae Cushman, P. cretacea Cushman, Bolivina cretosa Cushman, Planulina texana Cushman and Cibicides harperi (Sandidge).

<i>Delapparentia turolensis</i> nov. gen et sp., un nuevo dinosaurio iguanodontoideo (Ornithischia: Ornithopoda) en el Cretácico Inferior de Galve

Se redescribe un esqueleto postcraneal de dinosaurio ornitópodo asignado por Albert de Lapparent en 1960 a Iguanodon bernissartensis. Procede del yacimiento de La Maca 3, de edad Barremiense inferior (Formación Camarillas), y consta de varias vértebras cervicales, restos de la serie dorsal y sacra, varias vértebras caudales, fragmentos de costillas cervicales, dorsales, y esternales, chevrones y tendones osificados, y la hemipelvis izquierda incompleta. Se ha identificado como un «iguanodóntido» (i.e. un Iguanodontoidea no Hadrosauridae) por la presencia de una lámina prepubica alta y la ausencia de antitrocánter en el ilion. Se propone a partir de este material un nuevo taxón de iguanodontoideo, Delapparentia turolensis nov. gen et sp., caracterizado por las siguientes autapomorfías: 1) costillas dorsales posteriores con capítulo y tubérculo no fusionados, 2) costillas esternales osificadas, y 3) ilion con el proceso preacetabular torsionado y expandido lateromedialmente (compartida con Zalmoxes). Además presenta una combinación de costillas dorsales anteriores con un foramen neumático, e isquion grande en relación al ilion.

Rudist decline in the Maastrichtian Cardenas Formation (East-central Mexico)

Five sections of the Cardenas and Tabaco formations in east-central Mexico have been analyzed by means of bio-, Sr-isotope, and sequence stratigraphy, in order to evaluate their age as well as the timing of rudist decline. Ammonites [ Pachydiscus (Pachydiscus) neubergicus (Hauer), Sphenodiscus pleurisepta (Conrad), Coahuilites sheltoni Böse] indicate an early Maastrichtian age for the topmost lower member of the Cardenas Formation and planktic foraminifera [e.g., Globotruncanita stuarti (de Lapparent), Archaeoglobigerina cretacea (d’Orbigny), Globotruncanella petaloidea (Gandolfi), Gansserina gansseri (Bolli), Globotruncana linneiana (d’Orbigny)] a late early Maastrichtian age for the middle member corresponding to the foraminiferal zones CF5 and CF6. Sr-isotope stratigraphic data yield an early late Maastrichtian age (66.93 Ma < 67.98 Ma < 68.96 Ma) for the last rudist assemblage in the topmost upper member of the Cardenas Formation, coinciding with the foraminiferal zone CF4. 17 small-scale and 3 large-scale depositional cycles have been identified, which correspond to para- and depositional sequences. The progradational pattern of the large-scale cycles indicates an overall regression trend, which terminated in subaerial exposure of the area, indicated by paleosoils in the red beds of the Tabaco Formation. The correlation of the large-scale cycles with the global sea level charts indicate that eustatic sea level fall caused the regression and led to the exposure during the middle late Maastrichtian. This subaerial exposure resulted in the loss of habitat and thus the disappearance of rudists in east-central Mexico.

Eurotestudo, a new genus for the species Testudo hermanni Gmelin, 1789 (Chelonii, Testudinidae)

The new genus is created to include the species of the hermanni group, which is within Testudo s.l., a Palearctic genus, consequently separated from both Testudo s.s. and Agrionemys. A preliminary cladistic analysis of the osteological characters, including fossil species, demonstrated the splitting of the three lineages, probably since the Oligocene and surely at the Upper Miocene. Diagnosis of the new genus is based on a collection of features. The main stages of evolution leading to the three lineages are provided. We also describe external characters of the extant species that could be considered as diagnostic. However, phylogenetic relationships between genera are not definitively established. To cite this article: F. de Lapparent de Broin et al., C. R. Palevol 5 (2006) .

Early Permian (Asselian) brachiopods from Karakorum (Pakistan) and their palaeobiogeographical significance

Abstract: Early Permian (Asselian) brachiopods collected from the Gircha Formation of western Karakorum (Pakistan) are described. They include Bandoproductus girchensis sp. nov., Kiangsiella sp. indet., Trigonotreta lyonsensis Archbold and Thomas, Trigonotreta larghii sp. nov., Spirelytha petaliformis (Pavlova), Punctospirifer afghanus Termier, Termier, de Lapparent and Marin, and ?Dielasma sp. indet. and belong to the Trigonotreta lyonsensis–Punctospirifer afghanus Assemblage Biozone, the oldest so far recovered from the Permian succession of Karakorum. The faunal succession of Karakorum records a significant biotic change from the Asselian to the Sakmarian, a shift in diversity and composition that is also recorded along most of the Gondwanan margin and Peri‐Gondwanan regions and that should be related to a major climatic change: the end of the Gondwanan glaciation. A palaeobiogeographical analysis has been performed by means of multivariate methods applying cluster and ordination analyses based on the Jaccard Coefficient and Simpson Index to a matrix consisting of the presence/absence of 23 brachiopod genera from seven geographical operational units from central Afghanistan to eastern Australia. The results suggest the occurrence of a single biotic province during the Asselian, the Indoralian Province, embracing all the faunal stations examined, as a consequence of the global cold phase related to the last pulse of the Gondwanan glaciation.

Shapley and Hubble: Different Views Brought Galaxies Into Focus

Shapley and Hubble: Different Views Brought Galaxies Into Focus

A new Shachemydinae (Chelonii, Cryptodira) from the Lower Cretaceous of Laos: preliminary data

The Lower Cretaceous of Laos produced remains of freshwater cryptodiran turtles including some elements of aff. Xinjiangchelys and of Trionychoidea: Trionychidae, Carettochelyidae and beautiful specimens of a new species of Shachemys. The latter is defined, compared and placed in the family Adocidae. The family is reconsidered and the subfamily Shachemydinae is confirmed; the latter ranges from the Upper Jurassic to the Senonian of Asia. Its good adaptation to aquatic life is asserted. To cite this article: F. de Lapparent de Broin, C. R. Palevol 3 (2004) .

The ESO-Sculptor Survey: Evolution of late-type galaxies at redshifts 0.1–0.5

[ABRIDGED] Using the Gaussian+Schechter composite luminosity functions measured from the ESO-Sculptor Survey (de Lapparent et al. 2003), we obtain evidence for evolution in the late spectral class containing late-type Spiral (Sc+Sd) and dwarf Irregular (dI) galaxies. This evolution is detected as an increase of the Sc+Sd+dI galaxy density which can be modeled as either n(z)~1+3(z-0.15) or n(z) ~ (1+z)^2 using the currently favored cosmological parameters Omega_m=0.3 and Omega_Lambda=0.7, with an uncertainty in both evolution rates of order of unity. For Omega_m=1.0 and Omega_Lambda=0.0, the linear and power-law evolution rates are 4 and 2.5 resp. Both models yield a good match to the ESS BVRc redshift distributions to 21-22 mag and to the number-counts to 23-23.5 mag, which probe the galaxy distribution to redshifts z~0.5 and z~1.0 resp. This analysis illustrates how Gaussian+Schechter composite luminosity functions provide more robust constraints on the evolution rate than pure Schechter functions. The detected density evolution indicates that mergers could play a significant role in the evolution of late-type Spiral and dwarf Irregular galaxies. However, the ESO-Sculptor density increase with redshift could also be caused by a ~1 mag brightening of the Sc+Sd+dI galaxies at z~0.5 and a ~1.5-2.0 mag brightening at z~1, which is compatible with the expected passive brightening of Sc galaxies at these redshifts. Distinguishing between luminosity and density evolution is a major difficulty as these produce the same effect on the redshift and magnitude distributions. The detected evolution rate of the ESO-Sculptor Sc+Sd+dI galaxies is nevertheless among the range of measured values from the other existing analyses, whether they provide evidence for density or luminosity evolution.

Large-Scale Structure and the Redshift-Distance Relation

In efforts to demonstrate the linear Hubble law v=Hr from galaxy observations, the underlying simplicity is often obscured by complexities arising from magnitude-limited data. In this Letter, we point out a simple but previously unremarked fact: the shapes and orientations of structures in redshift space contain in themselves independent information about the cosmological redshift-distance relation. The orientations of the voids in the CfA slice support the Hubble law, giving a redshift-distance power index p=0.83±0.36 (void data from Slezak, de Lapparent, & Bijoui) or p=0.99±0.38 (void data from Malik & Subramanian).