J. Keith Rigby

LONG EXPECTED SPONGES FROM THE NEOPROTEROZOIC EDIACARA FAUNA OF SOUTH AUSTRALIA

ABsTRAC--New fossils from the Neoproterozoic Ediacara fauna of South Australia are interpreted as the oldest known hexactinellid sponges. They occur within the Ediacara Member of the Rawnsley Quartzite (Pound Subgroup) from several locations in the Flinders Ranges. The new genus, Palaeophragmodictya, is characterized by disc-shaped impressions preserving characteristic spicular networks and is reconstructed as a convex sponge with a peripheral frill and an oscular disc at the apex.

Discovery of 505-million-year old chitin in the basal demosponge Vauxia gracilenta

Sponges are probably the earliest branching animals, and their fossil record dates back to the Precambrian. Identifying their skeletal structure and composition is thus a crucial step in improving our understanding of the early evolution of metazoans. Here, we present the discovery of 505–million-year-old chitin, found in exceptionally well preserved Vauxia gracilenta sponges from the Middle Cambrian Burgess Shale. Our new findings indicate that, given the right fossilization conditions, chitin is stable for much longer than previously suspected. The preservation of chitin in these fossils opens new avenues for research into other ancient fossil groups.

ORDOVICIAN SPHINCTOZOAN SPONGES OF ALASKA AND YUKON TERRITORY

ABSTRAcr-In Coal Creek Canyon, Utah, the Spring Canyon Member of the Blackhawk Formation is divisible into four regressive hemicycles of deposition, each representing the downdip part of a nearshore-to-offshore sequence. The first and fourth hemicycles are best developed. Individual bedding units span middle-shoreface to lower-offshore lithofacies, the latter corresponding to a thin intertongue of Mancos Shale. Trace fossil assemblages include ~22 ichnospecies and 17 ichnogenera: Ancorichnus, Aulichnites, Chondrites, Cylindrichnus, Ophiomorpha, Palaeophycus, Phoebichnus, Planolites, Rosselia, Schaubcylindrichnus, Scolicia, Skolithos, Taenidium, Teichichnus, Terebellina, Thalassinoides, and Uchirites. Diversity and abundance of ichnospecies are greater in nearshore than in offshore lithofacies. Distal deposits are typified by obscure bioturbate textures: Cylindrichnus concentricus, Palaeophycus heberti, and Rosselia socialis are prevalent through the remainder of the lithofacies suite. Ophiomorpha irregulaire and Schaubcylindrichnus coronus are most common in middle-shoreface beds and Chondrites ichnosp. in upper-offshore beds; Ophiomorpha nodosa and O. annulata also are common in this part of the sequence.Extensive assemblages of Ordovician sphinctozoan sponges from Alaska and the Yukon Territory extend the early Paleozoic circum-Pacific record of the order. Sponges described here are of Llandeilian-Ashgillian (Middle and Upper Ordovician) ages. The fossils are, in part, from the White Mountains area, in the Nixon Fork terrane of west-central Alaska, and, in part, from the Livengood area, in the White Mountain terrane (Churkin et al., 1982). The easternmost sponges described here are from Jones Ridge, in the western Yukon. Fossil distributions suggest that the Jones Ridge rocks are autochthonous with North America and that the White Mountain terrane has not travelled far because it appears to have stratigraphic analogues across the Tintina Fault. Distributions also suggest that the Nixon Fork terrane has not travelled far, based on faunal similarities ofgastropods and brachiopods of the terrane, particularly, with those from North America. The new genera and species, Alaskaspongia nana and Pseudoporefieldia micella, the new porate species, Corymbospongia betella and Angulongia minuta, and the new aporate species, Cystothalamiella ducta and Cystothalamiella polyducta, represent the new taxa of the assemblage. In addition to these, Imperatoria media Rigby and Potter, 1986, Girtyocoelia(?) epiporata Rigby and Potter, 1986, and Cliefdenella obconica Rigby and Potter, 1986, along with Imperatoria? sp. and a distinct, though unidentifiable, genus and species make up the total fauna of eleven species.

Wewokella costata new species, a large heteractinid calcareous sponge from the upper Mississippian Hartselle sandstone in Northeastern Alabama

Several specimens of the gigantic new species, Wewokella costata , have been recovered from the Upper Missisippian Hartselle Sandstone of Marshall County, east of Huntsville, in northeastern Alabama. The large sponges have flutted columnar growths and basic skeletons of triactines that are grossly encrusted or overgrown by calcium carbonate to produce massive fused skeletons. These are the oldest and largest specimens of Wewokella yet certainly identified. Wewokella costata has a skeleton with reduced numbers of triactines, but with extensive calcareous cement. The species could be in the lineage leading to the Inozoida Rigby and Senowbari-Daryan, 1996, which have spicule-free skeletons of sphaeroidal aragonite.

Biogeography of Ordovician sponges

Sponges have an unrealized potential importance in biogeographic analysis. Biogeographic patterns determined from our analysis of all published data on distribution of Ordovician genera indicate Early Ordovician sponge faunas have relatively low diversity and are completely dominated by demosponges. Early Ordovician (Ibexian) faunas are characterized by the widespread co-occurrence of Archaeoscyphia and the problematic Calathium. This association is commonly found in biohermal structures. Middle Ordovician faunas show an increase in diversity, and two broad associations are differentiated: Appalachian faunas (including Southern China and the Argentine Precordillera) and Great Basin faunas. Late Ordovician faunas show important changes in diversity and provincialism. Hexactinellid and calcareous sponges became im- portant and new demosponge families appeared. Four Mohawkian-Cincinnatian associations are recognized here, including: 1) Mid- continent faunas; 2) Baltic faunas; 3) New South Wales faunas; and 4) Western North American (California and Alaska) faunas. However, two separate biogeographic associations are differentiated based on faunal differences. These are a Pacific association (western North American and New South Wales) and an Atlantic association (Midcontinent Laurentia and Baltica). Distribution of sponge genera and migration patterns are utilized to consider paleogeographic dispositions of the different continental plates, climatic features, and oceanic currents. Such an analysis points to close paleogeographic affinities between the Argentine Precordillera and Laurentian Appalachian faunas. However, significant endemicity and the occurrence of extra-Laurentian genera suggest a relative isolation of the Precordillera terrane during the Late Ibexian-Whiterockian. The study also shows a faunal migration from the Appalachian region to South China during the Middle Ordovician and the migration of faunas from Baltica to Laurentia in the Late Ordovician. The occurrence of Laurentian migrants in New South Wales during the Late Ordovician could be related to inferred oceanic current circulation between these two areas, although other paleogeographic features may be involved.

Upper permian segmented sponges from Djebel Tebaga, Tunisia

SummaryUpper Permian (late Murgabian and early Pamirian) reefs and interbedded terrigenous rocks exposed in Djebel Tebaga (southern Tunisia), represent the only marine deposits in the whole of the African continent. These carbonates contain one of the best preserved and most diverse sponge assemblages of Permian age. These fossiliferous deposits contain a rich faun and flora.The sponge fauna of the reef carbonates of Djebel Tebaga include representatives of the Demospongea, ‘Sclerospongea’, and Inozoa, as well as the thalamid sponge (‘Sphinctozoans’). The thalamid sponges are described in this paper and the taxa described by TERMIER & TERMIER (in TERMIER, TERMIER & VACHARD 1977a, this paper is cited as TERMIER & TERMIER 1977a) from the some locality are compared and evaluated. The following taxa are described as new:Amblysiphonella obliqua n. sp.,Amblysiphonella ramosa n. sp.,Amblysiphonella? bullifera n. sp.,Colospongia cortexifera n. sp.,Platythalamiella newelli n. g., n. sp.,Tristratocoelia rhythmica n. g., n. sp.,Pseudoamblysiphonella polysiphonata n. g., n. sp.,Cystothalamia ramosa n. sp.,Tebagathalmia cylindrica n. g., n. sp.,Solenolmia permica n. sp.Enoplocoelia interchora n. sp.,Sollasia? amaurosa n. sp. undAmphorothalamia cateniformis n. g., n. sp..A representative of the thalamid demosponges with monaxial spicules and with a new type of filling tissue is described asPisothalamia spiculata n. g., n. sp. (family Pisothalamiidae n. fam.) This sponge differs from other demosponges by having well developed outer and inner segmentation, by a new type of pisoid-like filling tissue and by other features. The new order Pisothalamida is proposed for this group of demosponges.Pisothalamia represents the first ‘sphinctozoan’ sponge with spicules, known from the Permian.The described fauna shows strong affintities on generic and specific levels to the sponge fauna known from the somewhat older allochthonous reef limestones of the Sosio Valley in Sicily.Observations on some specimens of thalamid sponges indicate that living sponges occupied more than the uppermost chambers in at least some species.ZusammenfassungDas einzige Vorkommen von marinem Perms auf dem afrikanischen Kontinent, die oberpermischen Riffkalke im Gebiet des Djebel Tebaga in Süd-Tunesien (oberes Murgab bis tiefes Pamir bzw. Midin), ist durch die reiche Fossilführung und durch die ausgezeichnete Erhaltung der Faunen-und Florenelemente berühmt.Die Schwämme sind durch Demospongien, Sclerospongien, Inozoen und durch thalamide Formen (“Sphinctozoa”) vertreten. Letzte werden im Rahmen dieser Arbeit aufgrund von umfangreichen Aufsammlungen systematisch dargestell und den von TERMIER & TERMIER (1977a, 1977b) beschriebenen Taxa gegenübergestellt (Tab. 4).Insgesamt konnten 24 Gattungen (darunter 6 neue Genera) und 29 Arten (14 neu) unterschieden werden. Folgende Taxa sind neu:Amblysiphonella obliqua n.sp.,Amblysiphonella ramosa n. sp.,Amblysiphonella? bullifera n. sp.,Colospongia cortexifera n. sp.,Platythalamiella newelli n. g., n. sp.,Tristratacoelia rhythmica n. g., n. sp.,Pseudoamblysiphonella polysiphonata n. g., n. sp.,Cystothalamia ramosa n. sp.,Tebagathalamia cylindrica n. g., n. sp.,Solenolmia permica n. sp.,Enoplocoelia interchora n. sp.,Sollasia? amaurosa n. sp., undAmphorithalamia cateniformis n. g., n. sp..Ein Vertreter der thalamiden Demospongia mit monaxonen Mikroskleren und einem neuen (‘pisoidischen’) Füllskelett-Typ wird alsPisothalamia spiculata n. g., n. sp. (Familie Pisothalamiidae n. fam., Ordnung Pisothalamida n. ord.) beschrieben.Pisothalamia stellt den ersten bekanten thalamiden Schwamm mit einem spikulärem Skelett im Perm dar.In der Fauna des Djebel Tebaga überwiegen Vertreter der ‘poraten’ Kalkschwämme.Ein Vergleich der in Tunesien auftretenden Taxa mit Schwammfaunen aus älteren Schichten (Venezuela— Word, etwa Kubergand; Sosio/Sizilien—etwa hohes Kubergand und tiefes Murgab) sowie aus jüngeren Schichten des höheren Perms (Texas—Capitan, etwa Midin bis unteres Pamir; Lichuan/China—Changsing, etwa Dorasham) zeigt, daß die größten Übereinstimmungen auf Gattungs-und Artenebene mit der aus Sizilien beschriebenen Fauna gegeben sind (Tab. 3). Einige der in der tunesischen Fauna vorkommende Gattungen treten auch in der Trias auf.Ein zur Lebzeiten der Schwämme erfolgter Algenbewuchs, der die Ostien ausspart, kann als Hinweis darauf angesehen werden, daß bei einigen thalamiden Schwämmen das Gewebe des lebenden Schwammes mehr als nur die “oberste” Kammer erfüllte.

FIRST OCCURRENCE OF AN IN SITU ANTHASPIDELLID SPONGE IN A DENDROLITE MOUND (UPPER CAMBRIAN; GREAT BASIN, USA)

Abstract Small silicified anthaspidellid sponges identified as Gallatinospongia conica Okulitch and Bell, 1955 are described for the first time from the Upper Cambrian of the Great Basin where the sponges are found in situ within dendrolitic microbial reefs. This association forms the oldest anthaspidellid-microbial reefs of Laurentia.

Fossil Sponges from a Localized Cold-Seep Limestone in Oligocene Rocks of the Olympic Peninsula, Washington

ABsTRACr-A limited fauna of relatively simple, thin-walled, hexactinellid sponges, including moderately coarse-textured, funnellike Hexactinella(?) conica new species, fine-textured, tubular to branched Hexactinella(?) tubula new species, fragments of delicate Eurete goederti(?) Rigby and Jenkins, 1983, and Farrea(?) species, has been found in the Oligocene Lincoln Creek Formation on Canyon River, in the southcentral part of the Olympic Peninsula, Washington. These sponges dominate a chemosynthetic invertebrate assemblage that included the gastropod Provanna antigua Squires, 1995; the polyplacophoran Leptochiton alveolus (Lov6n, 1846), and radiolarians. Most of the sponges are preserved as silica in a localized cherty and botryoidal, calcareous cement-filled limestone formed at bathyal depths by bacterial oxidation of methane at a cold seep. This is the third known report of sponges from ancient chemosynthetic deposits.

Upper Devonian Sponges from the Holy Cross Mountains, Central Poland

The rich fauna of Late Devonian (Late Frasnian) siliceous sponges from the Holy Cross Mountains, Poland is composed of 15 species and 11 genera. Both astylospongid demosponges (lithistids) and hexactinosan hexactinellids are present. The following new genera and/or species are proposed: D regulara Rigby and Pisera sp. nov., Jazwicella media Rigby and Pisera gen. et sp. nov., Astyloscyphia irregularia Rigby and Pisera gen. et sp. nov., A. turbinata Rigby and Pisera gen. et sp. nov., Astylotuba modica Rigby and Pisera gen. et sp. nov., Paleoregulara cupula Rigby and Pisera gen. et sp. nov., Paleoramospongia bifurcata Rigby and Pisera gen. et sp. nov., Cordiospongia conica Rigby and Pisera gen. et sp. nov., Paleocraticularia elongata Rigby and Pisera gen. et sp. nov., P gigantia Rigby and Pisera gen. et sp. nov., Polonospongiadevonica Rigby and Pisera gen. et sp. nov., P fistulata Rigby and Pisera gen. et sp. nov., Urnospongia modica Rigby and Pisera gen. et sp. nov., and Conicospongia annulata Rigby and Pisera gen. et sp. nov. The investigated fauna contains the youngest astylospongiids known and the oldest well-preserved, and most diversified Palaeozoic hexactinosans. The sponge fauna constituted a significant element of a brachiopod-coral-sponge assemblage that inhabited a deep slope of the local Dyminy Reef structure, during its final phase of growth, in a clearly hemipelagic setting. This fauna is limited to the intrashelf depression within an incipiently drowned carbonate platform.

SPONGES AND CHANCELLORIIDS FROM THE CAMBRIAN OF WESTERN ARGENTINA

Anthaspidellid sponges are reported from the La Laja Formation in the Chica de Zonda Range in the Precordillera Oriental, Argentina. These are generically unidentifiable fragments of trabs and more or less well-defined dendroclone spicules. They occur as skeletal elements in small transported fragments and are the only Cambrian occurrence of anthaspidellids known thus far from South America. Walcott (1920) proposed to include an array of dissociated spicules, including triradiate prodiaenes, hexactines, and probable monactine spicules, in the genus Kiwetinokia. Assemblages tentatively identified as Kiwetinokia utahensis ? Walcott, 1920, are reported from the Estancia San Martin Formation, of latest Early Cambrian and early Middle Cambrian age from San Isidro Gulch near Mendoza. Similar spicule assemblages occur in the La Laja Formation from the Chica de Zonda Range, in the Precordillera Oriental near San Juan, and in the Los Sombreros Formation in the Tontal Range of the Precordillera Occidental. Sclerites of the sponge-like Chancelloria eros Walcott, 1920, are described from the upper Lower to lower Middle Cambrian La Laja Formation. Chancelloria sclerites are also reported here from rocks of the Middle Cambrian Glossopleura Zone in the San Isidro Formation in Empozada Gulch in the San Isidro area of the Precordillera Austral, west of Mendoza, in Mendoza Province. Sponges and chancelloriids from the Cambrian of Argentina are known basically from dissociated skeletal elements.