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Neogene Decapod Crustacea from Southern Chile
Abstract and Figures
Twelve species of Neogene decapod crustaceans are described from late Miocene and early Pliocene deposits in the Valdivia, Osomo-Llanquihue, and Chiloé basins as well as from Mocha Island, offshore from the Temuco Basin, southern Chile. New species of thalassinideans include Ctenocheles notialis and Axianassa? chilensis. Axianassa Schmitt, 1924, has not been reported previously in the fossil record. New species of brachyurans include Trichopeltarion frassinetti. Pirulella antipodea, Chaceon quadrata, Geryon manningi, Phenophthalmus mochaensis, and Chasmocarcinus chiloeensis. Pirulella and Phenophthalmus are new genera and Geryon Krøyer, 1837, is noted in the fossil record for the first time. Extant congeners are primarily known from lower latitude regions. Only Chaceon Manning and Holthuis, 1989, is known from the Chilean coast at present.
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... Magallanes (Ortmann 1902). Las faunas fósiles comprende entre otros grupos a foraminíferos (Finger 2013;Hromic 1995;Ibaraki 2001), equinodermos (Larraín 1975), cangrejos (Feldmann et al. 2005(Feldmann et al. , 2010 y sobre todo moluscos (Herm 1969;Frassinetti y Covacevich 1993;Nielsen y Frassinetti 2007). Se ha descrito más de 500 especies de moluscos fósiles del Cenozoico chileno, a las que se suman los registros fósiles de especies actuales (Nielsen 2013;Nielsen y Valdovinos 2008). ...
La palabra fósil, que deriva del latín fossilis, fue empleada por Plinio (23-79 dC) para designar los objetos enterrados. En la actualidad, se refiere a evidencias de la vida en el pasado geológico, que presentan una estructura de origen biológico y que se han conservado en las rocas de la corteza. Los restos fósiles constituyen la prueba directa de la presencia de distintas formas de vida que han existido en nuestro planeta, remontándose los más antiguos a unos 3.000 millones de años. Este gran rango de tiempo posibi-litó la evolución de millones de formas de vida, que algunos autores (Raup, 1992) estiman entre 5 y 50 millones, la mayoría hoy extintas, sobreviviendo sólo algunos linajes casi sin cambios, mientras que otros evolucionaron y dieron origen a la actual biodiversidad. La biodiversidad extinta o paleobiodiversidad es rica y variada, pero des-conocida en su conjunto por la falta de especialistas y estudios continuos. La primera mención documentada que se conoce sobre fósiles de inver-tebrados en Chile es realizada por Degenhardt en 1839 sobre un bivalvo denominado Pecten alatus y procedente de Copiapó (figura 1). Para el caso de los vertebrados, la primera mención es realizada por Wyman en 1855 y se refiere a los restos de Mastodon andium, una forma muy similar a los actuales elefantes, pero mucho más robusta (figura 2). Hacia 1887, Philippi en su obra "Los fósiles terciarios i cuartarios de Chile" presenta las primeras descripciones de fauna fósil de invertebrados y vertebrados, siendo este trabajo el primer catálogo de fósiles para Chile. Con posterio-ridad, se efectúan varios trabajos aislados sobre otros grupos de fósiles, ampliando el conocimiento a nivel nacional. Si bien estos aportes han sido escasos, para dimensionarlos hay que considerar que entre 1855 y 1980 se publicaron solamente 44 trabajos sobre vertebrados fósiles, con un total de 429 páginas (Frassinetti, 1982). Sólo en 1980, gracias al trabajo de in-vestigadores como Manuel Tamayo y Daniel Frassinetti, se dispuso de un catálogo completo de la fauna de mamíferos actuales y fósiles de Chile, constituyéndose en un estudio de importancia al revisar también los aspec-tos de la nomenclatura utilizada sobre los materiales fósiles de mamíferos descubiertos en el país. Si bien, los mamíferos son el grupo mejor conocido, también existen importantes estudios sobre otros grupos de vertebrados fósiles. Afortunadamente en los últimos diez años se han generado valio-sas investigaciones que han contribuido a aumentar significativamente el conocimiento de la biodiversidad extinta en Chile. Con la finalidad de faci-litar el recorrido por la biodiversidad fósil el capítulo se ha dividido en dos grandes grupos de organismos: invertebrados y vertebrados.
... The Ayacara Formation consists of interbedded sandstone and siltstone with minor conglomerates and tuffs . Its fossils are scarce and poorly preserved, consisting of solitary corals (Solano 1978), echinoderms (Alarcón 1995), crustaceans (Feldmann et al. 2010), and foraminifera and silicoflagellates (Levi et al. 1966;Sernageomin 1995;Encinas et al. 2013). Strata are highly deformed and intruded by igneous dikes (Levi et al. 1966). ...
The most important Cenozoic marine transgression in Patagonia occurred during the late Oligocene–early Miocene when marine waters of Pacific and Atlantic origin flooded most of southern South America including the present Patagonian Andes between ~41° and 47° S. The age, correlation, and tectonic setting of the different marine formations deposited during this period are debated. However, recent studies based principally on U–Pb geochronology and Sr isotope stratigraphy, indicate that all of these units had accumulated during the late Oligocene–early Miocene. The marine transgression flooded a vast part of southern South America and, according to paleontological data, probably allowed for the first time in the history of this area a transient connection between the Pacific and Atlantic oceans. Marine deposition started in the late Oligocene–earliest Miocene (~26–23 Ma) and was probably caused by a regional event of extension related to major plate reorganization in the Southeast Pacific. Progressive extension and crustal thinning allowed a generalized marine flooding of Patagonia that reached its maximum extension at ~20 Ma. It was followed by a phase of compressive tectonics that started around 19–16 Ma and led to the growth of the Patagonian Andes. The youngest (~19–15 Ma) marine deposits that accumulated in the eastern Andean Cordillera and the extra-Andean regions are coeval with fluvial synorogenic deposits and probably had accumulated under a compressive regime.
... Pinnixa navidadensis ? Feldmann, Schweitzer and Encinas, 2005 [Miocene, Cardenal Caro] ( Feldmann et al., 2010). ...
Our knowledge of fossil crustaceans from the tropics has increased considerably during recent decades, thanks to novel findings and the re-examination of museum specimens. However, several previous records have been misidentified, numerous museum specimens have never been reported, and many new discoveries are yet to be published. Here, we present a detailed, up-to-date, and revised checklist for every marine, terrestrial, or freshwater fossil decapod crustacean occurrence from tropical America known to us, including their age, geographic occurrences, and related literature. We recognize the occurrence of at least 32 superfamilies, 69 families, 190 genera, and 415 species of brachyurans (‘true’ crabs), and anomurans (‘false’ crabs, hermit crabs, squat lobsters, and allies), several of them previously unknown. The checklist comprises records from three main geographic regions: 1) northern South America (Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela); 2) Central America and southern North America (Belize, Costa Rica, Honduras, Panama, Mexico, southern and central Florida); and 3) the Caribbean Islands + Bermuda (Anguilla, Antigua, Aruba, Bahamas, Barbados, Bermuda, Bonaire, Cuba, Curaçao, Dominican Republic, The Grenadines, Haiti, Jamaica, Puerto Rico, Saint Bartélemy, Saint Martin, Trinidad). Previous findings, new occurrences, and the revised systematic placement for several problematic/misidentified records, indicate that the fossil record of anomurans and brachyurans in tropical America is more diverse than previously envisioned, with a considerable degree of endemism at the genus- and species-levels.
Open acces http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104-64972017000100220&lng=en&tlng=en
... This can be also concluded for the retroplumids, which show high diversity in Eocene Tethys Ocean, with six different genera and two species of Retropluma Gill, 1894 known from Eocene strata of Europe (Vía Boada, 1959; Beschin et al., 1996;Artal et al., 2006Artal et al., , 2013; van Bakel, et al. 2010;Hyžný & müller, 2010;Gašparič & Hyžný, 2015). It was also observed that many taxa which evolved during this period were endemic to their regions of origin (FelDmann et al., 2010). ...
Increasing reports of genus Retropluma Gill, 1894 from the siliciclastic sediments of South-East Europe
demonstrate the abundance and preferred habitat of this genus in Miocene seas of Central Paratethys. In the
present paper we report new specimens of decapod Retropluma slovenica Gašparič & Hyžný, 2014, which extend
the known palaeogeographic and stratigraphic distribution of the species to the western borders of Slovenian
Basin of the Central Paratethys. The described specimens originate from the Early Miocene locality of Rovček in
the Tunjice Hills in Slovenia and exhibit associated preservation, characteristic for endobenthic infaunal mode
of living.
... Remarks: The studied isolated dactyli exhibit shape and dentition typical of Ctenocheles. The identification of the genus in the fossil record and discussion on the taxonomically important characters at the species level were discussed by Feldmann et al. (2010), , and Hyžný and Dulai (2014). Based on these studies, it is generally agreed that species-level identification is not possible if only isolated dactyli are available. ...
The locality of El Caracolar in the Granada Basin (Central Betic Cordillera, southern Spain) has yielded a rich late Miocene assemblage composed of marine invertebrates and vertebrates, accompanied by microfossils, macroflora and trace fossils. Exposed strata consisting of sands, sandy siltstones, silty sandstones, siltstones and calcirudites are divided into four local units. Lithostratigraphically, the studied section is placed between the top of the La Peza Formation and the Quéntar Formation. Based on foraminifers, the age of units 2 and 3 is estimated to be early Tortonian (11.0–9.9 Ma), whereas units 1 and 4 do not yield any reliable biostratigraphic markers. The diverse biotic association suggests that deposition took place in a near-shore outer neritic zone of a narrow to open seaway in a mesotrophic regime, responsible for the establishment of a chemosynthetic community under (sub)tropical conditions. The palaeo-depth of the depositional setting is estimated between 70 and 130 m. We further focus on decapod crustaceans that represent the first formally reported fossil decapod assemblage from the Granada province. The faunule consists of eight genera from two independent assemblages representing different palaeoenvironments. The assemblage of units 1 and 4 is dominated by the ghost shrimp “Callianassa” cf. almerai and accompanied by the hermit crab Petrochirus, whereas the assemblage from unit 3 includes the ghost shrimp Ctenocheles and the brachyuran crabs Raninoides, Calappa, Goneplax, Styrioplax, and Typilobus. Unit 2 does not yield any identifiable decapod remains. Styrioplax sp. represents the first occurrence of the genus outside the Central Paratethys, significantly expanding its palaeogeographical distribution. The decapod faunule from El Caracolar shows affinities with assemblages from the Proto-Mediterranean and Paratethys. This study provides a lithostratigraphic and palaeoenvironmental framework for further palaeontological studies in this unique Western Mediterranean outcrop.
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 of Huesca and the Miocene of Alicante and Mallorca. A morphological and petrographic study is carried out using conventional microscopy and Scanning Electron Microscopy to understand the microstructure in modern and fossil representatives. This provides a clear view of the mushroom-like structures that cover the carapace of Daira and the distribution of the different layers of the exoskeleton. The results reveal a complex morphology, which involves all layers of the cuticle, with changes in the thickness of the exocuticle in different areas, and the presence of conical structures that especially affect the outer layers. These convolutions form a network of channels connected to the outside by pores. Finally, possible anti-predatory functions of these complex structures are proposed.
A new brachyuran family is proposed in order to accommodate Montezumella Rathbun, 1930, previously assigned to Cheiragonidae Ortmann, 1893. The establishment of Montezumellidae n. fam. is based on the examination of several samples of both sexes of Montezumella, with well-preserved thoracic and abdominal structures. A new genus and species, Moianella cervantesi n. gen., n. sp. from the Priabonian (late Eocene) transitional levels of central Catalonia (NE of Iberian Peninsula) is described herein and assigned to the new family. The taxonomic placement of Montezumellidae n. fam. is discussed. Furthermore, "Atelecyclus" gorodiskii Rémy, 1959 in Gorodiski and Rémy, 1959, considered as atelecyclid, is herein attributed with reserve into the new family.
Although decapod crustaceans of the Central Paratethys were diverse during the Badenian (Langhian-Early Serravallian), a dramatic drop in their diversity occurred at the boundary with the Sarmatian. A crab Mioplax socialis is one of the few decapods reported from the Lower Sarmatian (Mohrensternia Zone) of the Paratethys. Until now, this species has been known from only a handful of specimens from Austria, Croatia and Bulgaria (Central Paratethys), and its systematics and ecology remain poorly known. Here, on the basis of new specimens from the Sarmatian tuffitic clays of the Stretava Formation (Skároš, Eastern Slovakia) we confirm that this species belongs to the subfamily Chasmocarcininae. The diagnostic characters of the male sternum that allow this classification are reported for the first time. The molluscan assemblage co-occurring with M. socialis demonstrate that this species tolerated conditions with variable salinity. Its tolerance of a broad range of salinity regimes may thus explain its survival across the Badenian-Sarmatian extinction event. Preservation of near-complete and fully articulated individuals of M. socialis suggests calm conditions and short residence times on the sediment-water interface.
Gastrópodos fósiles marinos, procedentes de Isla Guafo, en la Región de Los Lagos, sur de Chile, son descritos, comentados e ilustrados. El número de especies reconocidas alcanza a 18, de las cuales, ocho son propuestas como nuevas, lo que junto a 16 formas de bivalvos dadas a conocer anteriormente, hace un total de 34 especies de moluscos, bivalvos y gastrópodos fósiles, presentes en sedimentitas de diversas localidades en Isla Guafo. El análisis del conjunto fosilífero estudiado, refuerza las afinidades, ya planteadas, con asociaciones similares de isla Guamblín y Tubul (Formación Tubul en Arauco), constituyendo estas tres localidades, entidades equivalentes, tanto desde un punto de vista faunístico, como ambiental. La edad que sugieren los gastrópodos es coincidente con la conocida para los bivalvos para las mismas sedimentitas, es decir, Plioceno superior, que es la edad que se postula para la totalidad de la fauna de invertebrados fósiles marinos de Isla Guafo, en las localidades consideradas en el estudio llevado a cabo.
Se propone el nombre Lebucarcinus, nuevo género para una especie de Decápoda, Brachyura del Mioceno de Chile descrita primeramente como Cancer. Se señala a Cancer tyro Philippi , 1887, como la especie tipo del género y se designa un Neotipo para la especie de Philippi.
Se describe y comenta una fauna de bivalvos fósiles compuesta por 16 especies, procedente de Isla Guafo, en la Región de Los Lagos del sur de Chile. Nucula (Leionucula) subaraucana, Limatula covacevichi y Mulinia chilota son propuestas como especies nuevas. Esta fauna es comparada con diferentes asociaciones de bivalvos fósiles marinos del Neógeno chileno, análisis que sugiere su asignación al Plioceno. Tal consideración ha sido posible hacerla aún más precisa, específicamente al Plioceno Superior, sustentada por la presencia de tres especies que han sido propuestas con anterioridad, como fósiles característicos para esta época en Chile.
Seventeen fossil decapods are described from the Miocene of the Chichibu Basin, Saitama Prefecture Central Japan. The decapods occur in the Ushikubitoge Formation, Nagura Formation and Yokoze Formation. The following five are new: Trachycarcinus inflatus, Cancer sakamotoi, Itoigawaia chichibuensis, Maja morii, Miosesarma nagurense. Six decapod assemblages are recognized in the basin. The fauna is characterized by the predominance of muddy bottom inhabitants of the lower sublittoral zone, represented by the Miosesarma nagurense sp. nov. assemblage from the Nagura Formation. The occurrence of Maja morii sp. nov. is the first fossil record of the genus from the northern Pacific region.
The new species Chasmocarcinus robertsi from the upper Miocene Eastover Formation of Virginia is described and compared to other closely allied living and fossil representatives of this genus. The comparative morphology of fossil and living species demonstrates that the fossil genus Falconoplax Van Straelen, 1933, is a junior subjective synonym of Chasmocarcinus Rathbun, 1898. Chasmocarcinus robertsi occurs in, or was derived from, Miocene strata, not "?Paleocene beds' as reported by previous authors. Specimens of C. robertsi found near Little Cove Point, Maryland represent the northernmost known occurrence of living or fossil Chasmocarcinus. -Authors
Thirty-six species of fossil crab are described and figures from the Neogene of Sabah, Sarawak and Brunei. The following 3 genera, 31 species and 3 subspecies are new: Dorippe frascone tuberculata, Calappa sexaspinosa, Podophthalmus fusiformis, Charybdis feriata bruneiensis, Portunus obvallatus, P. woodwardi, Galene stipata, Parthenope (Rhinolambrus) sublitoralis, Ampliura (gen. nov.) simplex, Drachiella guinotae, Iphiculus granulatus, I. miriensis, I. sexspinosus, Leucosia longiangulata, L. serenei, L. tutongensis, Myra brevisulcata, M. subcarinata, M. trispinosa, Nucia borneoensis, N. calculoides, N. coxi, Nucilobus (gen. nov.) symmetricus, Pariphiculus gselli beetsi, P. papillosus, P. verrucosus, Philyra granulosa, Typilobus marginatus, Palaeograpsus bittneri, Pinnixa aequipunctata, P. omega, Prepaeduma (gen. nov.) decapoda, Xenophthalmus subitus, Macrophthalmus (Maerotis) wilfordi. -Authors