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A new plate-like hypercalcified chaetetid demosponge (Loiscupula bachendensi gen. nov. sp. nov) from the Cantabrian Zone (Moscovian, Pennsylvanian, NW Spain)

Diego Corrochano and Ronald R. West

Plain Language Abstract

A new type of aragonitic hypercalcified chaetetid sponge, Loiscupula bachendensi gen. nov. sp. nov. (Demospongiae), is described from the Bachende Formation (Carboniferous) in the Cantabrian Mountains, NW Spain. Cathodoluminescence microscopy revealed non-luminescent structures that are interpreted as calcitic pseudomorphs of monoaxon and polyaxon spicules. The form and arrangement of these spicule pseudomorphs, and the round and concentric basal skeleton with an inferred central point of attachment described herein, are features not reported from previous chaetetids. The sedimentologic context and the associated biota suggest that Loiscupula thrived in a muddy, low to moderate energy environment, within the euphotic zone.

Resumen en Español

Una nueva esponja chaetétida hipercalcificada (Loiscupula bachendensi gen. nov. sp. nov) de la Zona Cantábrica (Moscoviense, Pensilvaniense, NW de España)

Una nueva esponja chaetétida hipercalcificada, Loiscupula bachendensi gen. nov. sp. nov. (Demospongiae), ha sido recogida en la Fm Bachende (Kashiriense superior/Myachkoviense inferior) en la Zona Cantábrica (NW de España). Loiscupula tiene un esqueleto basal circular, concéntrico y laminar, y algunos ejemplares muestran estructuras cilíndricas y chimeneas ramificadas creciendo en la superficie superior. El esqueleto está formado por túbulos poligonales (en su mayoría hexagonales) o redondeados, que se disponen perpendiculares a la superficie del fósil y describen el típico patrón en panal de abeja de los chaetétidos. La microscopía de catodoluminiscencia ha revelado pseudomorfos no luminiscentes de espículas poliaxonas y monoaxonas, raramente monoactinas del tipo estilo; éstos están irregularmente distribuidos, aunque hay evidencias que sugieren que una estructura espicular existió. El esqueleto basal está formado por calcita neomórfica con bajo contenido en Mg (1.7 mol% MgCO3) y está fuertemente recristalizado; la microestructura penicillar con relictos de aragonito y el elevado contenido de Sr (hasta 3456 ppm), sugieren que la composición original de Loiscupula era aragonítica. Loiscupula se interpreta como un organismo gregario que probablemente se sujetaba al sustrato mediante un punto central de anclaje. Este modo de crecimiento, produjo pequeñas cavidades crípticas entre Loiscupula y el fondo marino, que fueron colonizadas por organismos incrustantes, en su mayoría briozoos fistulipóridos. Los fósiles asociados y los datos sedimentológicos, sugieren que Loiscupula habitó en fondos fangosos dentro de la zona eufótica, con aguas bien oxigenadas, de salinidad normal, y con un régimen energético de bajo a moderado.

Palabras clave: nuevo género; esponjas chaetétidas hipercalcificadas; algas filoides, Pensilvaniense, Zona Cantábrica, España

Traducción: Los autores

Résumé en Français

ne nouvelle démosponge plate hypercalcifiée (Loiscupula bachendensi gen. nov. sp. nov) du la Zone Cantabrienne (Moscovien, Pennsylvanien, N-O de l'Espagne)

Une nouvelle éponge chaetetidé hypercalcifiée, Loiscupula bachendensi gen. nov. sp. nov. (Demospongiae), a été extraite de la Formation Bachende (Kashirien supérieur/ Myachkovien inférieur) dans la Zone Cantabrienne, N-O de l'Espagne. Loiscupula a un squelette basal circulaire, concentrique et plat, avec quelques caractères cylindriques et des cheminées, qui se ramifient parfois à la surface supérieure. Le squelette basal est formé de tubules polygonales (généralement hexagonales) a arrondies, perpendiculaires à la surface du squelette produisant le schéma en nid d'abeille caractéristique des chaetetidés. La microscopie par cathodoluminescence a révélé une calcite des pseudomorphes du monoaxon et des spicules du polyaxon non-luminescente, rarement des styles, qui sont repartis irrégulièrement bien qu'il y ait des occurrences qui suggèrent qu'un le réseau spiculaire existait. Le squelette basal est composé de calcite néomorphique pauvre en Mg (1,7 mol% MgCO3) et est fortement recristallisée; la microstructure pénicillée provisoire avec des reliques d'aiguilles en aragonite, et le fort taux de Sr (jusqu'à 3456 ppm), suggèrent une composition d'origine en aragonite. Loiscupula est interprété principalement comme un organisme grégaire avec un point d'attachement central probable. Ce mode de croissance produit des petites cavités cryptiques entre Loiscupula et le substrat, qui étaient occupés par des organismes encroûtant, principalement des bryozoaires fistuliporidés. Sur la base des fossiles associées et des caractéristiques du sédiment, il est suggéré que Loiscupula habitait des environnements avec un fond boueux dans une zone euphotique, ou l'eau était bien oxygénée, de salinité normale, et avec un régime énergétique de bas à modéré.

Mots clés : nouveaux genre, démosponges chaetetidé hypercalcifiée, algue phylloïde, Pennsylvanien ; Zone Cantabrienne; Espagne

Translator: Olivier Maridet

Deutsche Zusammenfassung

Ein neuer plattiger hyperkalzifizierter chaetetider Hornkieselschwamm (Loiscupula bachendensi gen. nov. sp. nov) aus der Kantabrischen Zone (Moscovium, Pennsylvanium, Nordwestspanien)

Es wurde ein neuer hyperkalzifizierter chaetetider Hornkieselschwamm Loiscupula bachendensi gen. nov. sp. nov. (Demospongiae) aus der Bachende Formation (spätes Kashirium/frühes Myachkovium) in der Kantabrischen Zone von Nordwestspanien entdeckt. Loiscupula hat ein kreisförmiges, konzentrisches und plattiges Basalskelett, mit einigen cylindrischen Merkmalen und Schloten, die mitunter auf der Oberseite verzweigen. Das Basalskelett setzt sich aus polygonalen (meist hexagonal) bis gerundeten kleinen Röhren zusammen, die senkrecht zur Skelettoberfläche orientiert sind und das charakteristische Wabenmuster der Chaetetiden aufbauen. Kathodenluminiszes-Mikroskopie zeigte nicht-luminiszierende kalzitische Pseudomorphe von monaxonen und polyaxonen Spiculae, die irregulär verteilt sind obwohl Hinweise ein spiculares Netz existieren. Das Basalskelett besteht aus neomorphem fast reinem Kalzit (1.7 mol% MgCO3) und ist stark rekristallisiert; die geschätzte penicillate Mikrostruktur mit Relikten von Aragonitnadeln und die hohe SR-Konzentration (bis zu 3456 ppm) weisen auf eine ursprüngliche Aragonitzusammensetzung hin. Loiscupula wird als hauptsächlich geselliger Organismus angesehen, der einen geschlossenen zentralen Ansatzpunkt hatte. Diese Wachstumsart erzeugte kleine, kryptische Hohlräume zwischen Loiscupula und dem Substrat, die von überkrustenden Organismen, meist fistuliporide Bryozoen besiedelt waren. Aufgrund von assoziierten Fossilien und sedimentologischen Eigenschaften wird vorgeschlagen, dass Loiscupula ein Milieu in der euphotischen Zone bewohnte. Dieses hatte einen schlammigen Boden, gut mit Sauerstoff versorgtes Wasser, normale Salinität und ein niedriges bis moderates Energieregime.

Schlüsselwörter: neue Gattung; chaetetider hyperkalzifizierter Hornkieselschwamm; phylloide Algen; Pennsylvanium; Kantabrische Zone; Spanien

Translator: Eva Gebauer

Arabic

351 arab

Translator: Ashraf M.T. Elewa

 

 

diegoThis email address is being protected from spambots. You need JavaScript enabled to view it.
Facultad de Ciencias
Departamento de Geología
Universidad de Salamanca
Plaza de los Caídos s/n, 37008
Salamanca, Spain 

Diego Corrochano finished his PhD in 2010 on the cyclicity and sedimentology of Pennsylvanian carbonate successions at the University of Salamanca, Spain. He is currently studying the paleontology of marine invertebrates revealed by CT, with special emphasis on chaetetids and phylloid algae. Other research interests include carbonate diagenesis, sequence stratigraphy and basin analysis.

 

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ronaldThis email address is being protected from spambots. You need JavaScript enabled to view it.
1014 Houston Street
Manhattan, Kansas 66502
USA 

Ron West, though currently retired, continues his life long interest in the stratigraphy and invertebrate palaeobiology of the Carboniferous and Permian. Presently he is a Research Associate of the Natural History Museum and Biodiversity Institute at the University of Kansas; Adjunct Senior Scientist; Kansas Geological Survey and Emeritus Professor of Palaeobiology and Biology; Kansas State University. Research efforts, the last 30+ years, has focused on fossil and extant chaetetid demosponges and the seven chapters on them for the Treatise on Invertebrate Paleontology will soon be completed.

 

 

TABLE 1. Minor element content (ppm) of Loiscupula skeletons from the Bachende Formation.

 

Type (ppm)

Mg

Mn

Fe

Sr

USAL LB2

3821

60

4246

2863

USAL LB4

3804

168

8477

1943

USAL LB5-5

4535

103

5717

2365

USAL LB5-13

5033

119

4636

1482

USAL LB22

4423

66

4266

3456

Average

4323

103

5468

2422

 

FIGURE 1. 1, Geographical setting of the collection site, a roadcut on the eastern side of the Salamón-Lois road (León, NW Spain). 2, Geological sketch map of the Cantabrian Zone showing the location of the Lois-Ciguera sector (modified from Pérez-Estaún et al., 1988).

 fig1

FIGURE 2. Schematic section of the Bachende Formation showing the stratigraphic position of the type locality.

fig2 

FIGURE 3. General morphologic features of Loiscupula bachendensi gen. nov. sp. nov. from the Bachende Formation , Cantabrian Zone, NW Spain. 1, type locality of Loiscupula bachendensi in the Bachende Formation, arrows point to different specimens. 2-6 Holotype USAL LB1, 2, side view showing the flat cup-shaped skeleton, with the central part of the specimen lower than the outer edges. 3, top view, showing the wackestone matrix filling the cup. 4, underside of the sponge, showing the plate-shape and the concentric rings around a central point; note the projected structures developed within each ring and usually preserved as eroded (truncated) protuberances (arrow). 5, enlargement of the rectangular area in Figure 3.4, showing in detail one of the projections on the underside of the specimen. 6, close-up of the undulating underside of the skeleton, showing the eroded protuberances and encrusting bryozoans; B= bryozoans, Bq= brachiopod. 7-8, Paratype USAL LB5, 7, cylindrical feature (rectangle) growing up from the upper surface of the skeleton of Loiscupula (white arrows); B= brachiopod. 8, close-up of the rectangular area in Figure 3.7; arrows point to the poorly preserved microstructure of Loiscupula. Note the abundant foralgal encrustations (E); T= Tuberitina; Sp= sparry calcite.

fig3 

FIGURE 4. Internal structure of Loiscupula bachendensi gen. nov. sp. nov. 1, paratype USAL LB22, close-up showing the honey-comb pattern of the surface of Loiscupula bachendensi. 2, paratype USAL LB5, internal structure of the plate-like basal skeleton (enclosed by white dashed lines); white arrows point to vertical growth interruptions of the tubules; O= Ozawainella; P= pyrite. 3-4, paratype USAL LB29, 3, photomicrograph showing the internal structure of a cylindrical feature developed on the upper surface of the skeleton. 4, close-up of tubules at the upper edge of the skeleton. 5-6, Holotype USAL LB1, 5, transversal section of a cylindrical form; note the internal cavity, filled-up with micritic matrix, and the internal structure of Loiscupula composed of tubules. 6, close-up of the rectangular area in Figure 4.5 (rotated 45º counterclockwise); note the increasing of new tubules by intertubule increase (white arrow) and their horizontal partitions at different levels (T= tabulae). 7-8, paratype USAL LB5, 7, plane polarized light photomicrograph showing the overall recrystallization of the basal skeleton. 8, cathodoluminescence image of same field of view as Figure 4.7, showing the internal structure of the skeleton with development of poorly defined tabulae (arrowed).

 fig4

FIGURE 5. 1-8, Paratype USAL LB 5, spicule pseudomorphs of Loiscupula bachendensi gen. nov. sp. nov. All the images, except Figure 5.3, are cathodoluminescence photomicrographs. 1, Oxea (O) spicule pseudomorph floating in the surrounding matrix; white arrow is pointing to an (algal?) encrustation on the upper surface of the skeleton; T= tabulae; L=laminae, indicated by white dashed lines; note that tubules may be continuous or discontinuous across the growth interruptions. 2, intraskeletal non-luminescent spicule (mostly oxeas) pseudomorphs in a fragment of Loiscupula; white dashed line indicates the outer edge of the basal skeleton of Loiscupula; M= micritic matrix. 3, 4, plane polarized light and cathodoluminescence photomicrographs showing the internal structure of the plate-like basal skeleton; C= void filling cement; L= Loiscupula; M= micritic matrix. 5, close-up of the rectangular area in Figure 5.4, showing in detail a polyactine (P) and pseudomorphs of style spicules (S) embedded in the basal skeleton. 6, Oxea (O) and reduced polyaxon (P) spicule pseudomorphs and a probable pseudomorph of tylostyle spicule (T); dashed line indicates a fragment of Loiscupula. Note the dull appearance of the surrounding matrix and the bright to yellow-dull CL of the skeletal calcite. 7, Spicule pseudomophs concentrated towards the upper edge of the basal skeleton; dashed line indicates a transversal section of Loiscupula; T= tabula. 8, Close-up view of the rectangular area in Figure 5.5; arrow points to spicule pseudomorphs projecting into a tubule.

fig5 

FIGURE 6. 1-6, Paratype USAL LB 5, spicule pseudomorphs and microstructure of Loiscupula bachendensi gen. nov. sp. nov. All the images are cathodoluminescence photomicrographs, except Figure 6.6, which is a scanning electron micrograph. 1, strongly recrystallized fragment of Loiscupula (L) floating in a microspartic matrix (M). 2, cathodoluminescence image of same field of view as Figure 6.1, showing abundant spicule pseudomorphs embedded in the basal skeleton; note that they are absent in the surrounding matrix; L= Loiscupula; M= matrix. 3, close-up of the rectangular area in Figure 6.2, showing in detail several pseudomorphs of oxea pseudomorphs; arrows point to spicule cross sections. 4, 5, plane polarized light and cathodoluminescence photomicrographs showing a Tuberitina specimen (T) with well developed cathodoluminescence zonation; (P) polyaxon spicule pseudomorph floating in the surrounding microsparitic matrix with some rays shortened an others missing (arrows); O= pseudomorphs of oxea spicules with irregular edges. 6, Relic fascicular penicillate microstructure of Loiscupula, composed of fibers, inferred to be aragonite needles (white arrows) within coarse calcite crystals (black arrows).

 fig6

FIGURE 7. 1, Paratype USAL LB 5, Loiscupula (L) fragments floating in a muddy matrix; Ls= lasiodiscids; C=cyanobacteria filaments (Girvanella?); S= Shamovella. 2-4, USAL LB34, 2, polished slab showing the matrix that filled the cup-like skeleton of Loisphyllum (arrowed), with a complex intergrowth of Archaeolithophyllum lamellosum; note the undulating morphology of the Loiscupula skeleton (white dashed lines), representing the circular and concentring rings (grooves and ridges) in transverse section. 3, Archaeolithophyllum thallus showing relics of coaxial perithallum and hypotallum organization. 4, close-up view of the rectangular area in Figure 6.2; note the neomorphic calcite forming the basal skeleton and the poor preservation of the tubules (arrow); A= blade fragments of Archaeolithophyllum. 5, paratype USAL LB38-1, polished slab of a Loiscupula bachendensi specimen (black arrow and dashed line) with a fistuliporid bryozoan encrusting (lower left of the image) the underside of the specimen; note the development of the complex intergrowth of Archaeolithophyllum lamellosum (white arrows) in the wackestone matrix and the encrustations of small foraminifers (F), usually developed on the upper surface of the phylloid blades and Loiscupula. T= small specimen of Tetrataxis. 6, paratype USAL LB24, transversal section of a small specimen of Loiscupula bachendensi, showing the internal wackestone matrix filling the cup-shaped skeleton (dashed lines).

 fig7

FIGURE 8. Idealized reconstruction of Loiscupula bachendensi gen. nov. sp. nov. Note the low conical growth form; A= presumed attachment point; P= projections on lower surface; G= grooves; R= ridges; Pl= plate-like skeleton; C)= cylindrical/branching features (extended mamelons/chimneys) on upper surface.

fig8