Annelid Borings on Brachiopod Shells From the Upper Ordovician of Peru. A Long-Distance Co-migration of Biotic Partners

The Recent planktonic larvae of the polychaete spionids are some of the most widespread and abundant group of coastal meroplankton worldwide. To study the possible co-migration of biotic partners and determine whether they were host-specific, the type of biotic relationship between hosts and borers of an Upper Ordovician Peruvian brachiopod collection from the Proto-Andean margin of Gondwana was re-exanimated and compared with material from Wales (Avalonia). The species list studied is composed of Colaptomena expansa (41%), Heterorthis retrorsistria (24%), Horderleyella chacaltanai (19%), Drabovinella minuscula (13%), and Dinorthis cf. flabellulum (3%) and coincides closely with that of the Dinorthis community described in the Caradoc series of North Wales. The borings attributed to these spionids have been identified as Palaeosabella prisca only present in the valves of Colaptomena expansa and Heterorthis retrorsistria. All the studied valves are disarticulated, with very low fragmentation and are randomly oriented in a context below the fair-weather wave base. The settling larvae would feed on their brachiopod host soft parts at an early stage, being the biotic interaction initially of the parasitic type. Since Palaeosabella borings from Peru and Wales are identical, as well as the species specificity of their producers with their brachiopod hosts, it can be concluded that the same spionid annelid species produced them. The Southern Westerlies current that connected the Proto-Andean margin of Gondwana with Avalonia must have been responsible for transporting the larvae of annelids and brachiopods in what had to be a successful biotic relationship over a great transoceanic distance

Iberian Ordovician chronostratigraphy

La nuevas divisiones de la escala global del Sistema Ordovícico, con excepción de los pisos Tremadociense e Hirnantiense, son difíciles de aplicar en la Península Ibérica, pues sus estratotipos de límite radican en facies y faunas de aguas profundas, desconocidas en las plataformas someras y de paleolatitud elevada del ámbito peri-gondwánico. Antes de ello, la escala regional británico-avalónica fue utilizada en Iberia durante todo el siglo XX, pero presenta serios inconvenientes de correlación vinculados con la propia evolución, conceptual y de criterio, registrada en las áreas tipo británicas durante los últimos 40 años. Sin embargo, la escala regional bohemo-ibérica es la que actualmente aporta una mayor precisión a las correlaciones, pues se basa en elementos bioestratigráficos y biocronológicos de distribución común a todo el margen peri-gondwánico europeo y norteafricano, y la que mantiene vínculos episódicos con otras escalas regionales, que permitirán resolver progresivamente las equivalencias con la escala global.The new divisions from the global scale for the Ordovician System, except for the Tremadocian and Hirnantian stages, are difficult to correlate in the Iberian Ordovician, because their GSSPs involve deep-water facies and faunas not recorded in the shallow, high-paleolatitudinal settings of the peri-Gondwanan area. Previously to the Global scale, the British-Avalonian regional scale had been widely adopted in the Iberian Ordovician during all the 20th Century, but there are serious correlation problems due to the former’s conceptual evolution and variable criteria used for the British type areas during the last 40 years. However, the use of the Bohemo-Iberian scale instead, provides better precision to Iberian correlations, because it is based in some local biostratigraphical and biochronological markers, widely recorded over an extensive area of the European and North African peri-Gondwanan margin. The Bohemo-Iberian scale shows episodic links with other regional scales, which will provide indirect correlations also with the global Ordovician scale.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEMinisterio de Economía y Competitividad (MINECO)pu

Filling the Gondwanan gap:paleobiogeographic implications of new crinoids from the Castillejo and Fombuena formations (Middle and Upper Ordovician, Iberian Chains, Spain)

A diverse crinoid fauna is described from the Upper Ordovician (Katian) Fombuena Formation from the eastern Iberian Chains of Spain. New crinoids include the diplobathrid camerates Fombuenacrinus nodulus n. gen. n. sp., Goyacrinus gutierrezi n. gen. n. sp., Dalicrinus hammanni n. gen. n. sp., and Ambonacrinus decorus n. gen. n. sp.; the monobathrid camerate Eopatelliocrinus hispaniensis n. sp.; and the cladid Picassocrinus villasi n. gen. n. sp. A new occurrence of Heviacrinus melendezi Gil Cid, Domínguez Alonso, and Silván Pobes, 1996 is also documented from the Castillejo Formation (Darriwilian, Middle Ordovician) from the eastern Iberian Chains of Spain. The Fombuena Formation comprises a Gondwanan crinoid assemblage from a high paleolatitude and has the highest crinoid diversity of any currently known Katian Gondwanan fauna. This assemblage is compared to other Katian age faunas around the globe, and its paleobiogeographic implications are discussed.School of Earth Sciences, The Ohio State University, Estados UnidosNatural History Museum of Denmark, University of Copenhagen, DinamarcaUnidad de Zaragoza, Instituto Geológico y Minero de España, EspañaDepartment of Paleobiology, National Museum of Natural History, Estados Unido

Upper Onlovician trilobites from the Tremedal inlier, Castilian branch of the Iberian Range,NE Spain

Se revisa la sucesión del Ordovícico Superior al oeste de Noguera de Albarracín (Teruel), identificándose dos horizontes con trilobites y otros fósiles. El más antiguo se sitúa hacia la parte media de la Formación Bronchales y es de edad Berouniense (Sandbiense/Katiense en la escala global), conteniendo trinucleidos (Deanaspis), illaénidos (Vysocania) y dalmanítidos (Dalmanitina). El horizonte siguiente se localiza en la base de la Fm. Caliza de Cistoideos y es de edad Kralodvoriense (Katiense 3-4), con plioméridos (Ovalocephalus) e illaénidos (Cekovia?). El registro de trilobites y braquiópodos del Ordovícico Superior es particularmente escaso en la rama castellana, donde las formas representadas en la Fm. Bronchales permiten la correlación de esta unidad con la Fm. Fombuena de la rama aragonesa. Al N y NO del Macizo del Tremedal, los materiales berounienses no se depositaron (o fueron erosionados) previamente a las unidades calcáreas del Kralodvoriense. La localización del nivel con Deanaspis cf. seunesi permite situar estratigráficamente las citas locales de trinucleidos, mencionados desde mediados del siglo XX pero nunca descritos o figurados, razón por la cual se añade un pequeño apartado sistemático para este taxón.The revision of the Upper Ordovician sequence west of Noguera de Albarracín (Teruel Province) yielded two horizons with trilobites and other fossils. The oldest horizon occurs toward the middle part of the Bronchales Formation and is of Berounian (late Sandbian-early Katian) age, bearing trinucleids (Deanaspis), illaenids (Vysocania) and dalmanitids (Dalmanitina). The youngest studied horizon is located at the base of the Cystoid Limestone Fm. and yielded pliomerids (Ovalocephalus) and illaenids (Cekovia?) of Kralodvorian (Katian 3-4) age. The record of Upper Ordovician fossils in the Castilian branch of the Iberian Range is particularly scarce, and the Bronchales Fm. association now described supports the correlation of this unit with the Fombuena Fm. of the Aragonian branch. Towards the N and NW of the Tremedal inlier, Berounian rocks are absent due to non-deposition or erosion before younger calcareous sedimentation took place. This revision allows to locate a trinucleid trilobite-bearing horizon briefly mentioned in the mid-20th Century but never described or figured. Herein we pinpoint the stratigraphical position of this classical horizon and, due to its importance, present a short systematic section on Deanaspis cf. seunesi.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEMinisterio de Economía y Competitividad (MINECO)IUGS-UNESCOpu