594

J. Paleont., 80(3), 2006, pp. 594–600Copyright � 2006, The Paleontological Society0022-3360/06/0080-594$03.00

LATE CRETACEOUS SILICEOUS SPONGES FROMEL RAYO FORMATION, PUERTO RICO

ANDRZEJ PISERA,1 MICHAEL MARTINEZ,2 AND HERNAN SANTOS3

1Institute of Paleobiology, Polish Academy of Sciences, ul. Twarda 51/55, 00-818 Warszawa, �apis@twarda.pan.pl�, 2Earth Science EducationProgram, Universidad del Este, Carolina Campus, Puerto Rico, and 3Department of Geology, University of Puerto Rico, Mayaguez Campus

→

FIGURE 4—Morphology of sponges. 1, 2, Tetraclone-bearing lithistid sponges close to Phymatella Zittel, 1878; 1, specimen ZPAL Pf.16/1, 2, specimenZPAL Pf.16/2. 3, Longitudinal cross section of the same lithistid form (specimen ZPAL Pf.16/8), showing the canal openings on the surface ofspongocoel; 4, undetermined lithistid, specimen ZPAL Pf.16/3; 5, undetermined tetraclone-bearing lithistid, specimen ZPAL Pf.16/5. Scale bars 1 cm.

FIGURE 1—1, Location of the island of Puerto Rico. 2, Location of thestudy area on the Sabana Grande Quadrangle. CMF–Cerro Mula FaultZone; GSPRFZ–Great Southern Puerto Rico Fault Zone.

FIGURE 2—Stratigraphic section of the El Rayo Formation at 500 m westof Quebrada Martina.

INTRODUCTION

THIS PAPER presents sponges from the Late Cretaceous El RayoFormation, Puerto Rico. Siliceous sponges are common fos-

sils in the Late Cretaceous of Europe (see for example Schram-men, 1910–1912; Moret, 1926; Weidenmayer, 1994; Pisera,1999). So far only rare siliceous sponges from the Late Creta-ceous of the Caribbean region have been reported: lithistid ?JereaLamouroux, 1821, hexactinellids Ventriculites Mantell, 1822, andPlocoscyphia Reuss, 1846 from Trinidad (Thomas, 1935; Trech-mann, 1935), and Callopegma Zittel, 1878 from the CariblancoFormation, Puerto Rico (Howell, 1966). The sponges studied byus are heavily silicified and thus only their approximate deter-mination was possible, but among bodily preserved sponges they

are undoubtedly lithistids with tetraclone and rhizoclone desmas.Among loose spicule material, fragments of hexactinellid skeletondominate, tetraclone and dicranoclone lithistids desmas are com-mon, and hexactinellid lychniscosid skeletons are very rare.

GEOLOGICAL SETTING

The island of Puerto Rico is the easternmost island of the Ca-ribbean Greater Antilles (Fig. 1.1), a complex island arc withaccreted terranes. The island is composed of Lower Jurassic toLower Cretaceous ophiolites, Lower Cretaceous to Eocene islandarc volcanic and sedimentary rocks, Middle Oligocene to Plioceneterrigenous clastics, and limestone unconformably overlying theolder rocks along the north and south coasts (Santos, 1999). The

595PALEONTOLOGICAL NOTES

←

FIGURE 3—Cut and acid-etched slab of a sponge-bearing rock, specimenZPAL Pf.16/8. Note dense packing of sponges; silicified part of asponge is light grey (marked in some places with ‘‘s’’) and calcifiedone is dark gray (marked in some places with ‘‘c’’). Scale bar 2 cm.

pre-Oligocene rocks are divided into the southwest, central, andnortheast igneous provinces (Fig. 1.2).

The paleogeographic setting of the earliest island arc volcanismdiffered in each of the three igneous provinces (Santos, 1999).The southwest igneous province is separated from the rest of theisland by the Great Southern Puerto Rico Fault Zone (Fig. 1.2).It contains a basal ‘‘Bermeja Complex,’’ which is characterizedby linear bodies of serpentinite, blocks of mafic metamorphicrocks, and cherts of Pleinsbachian to Aptian age (Schellekens etal., 1993; Schellekens, 1998). This basal complex is unconform-ably overlain by a thick sequence of Santonian to Maastrichtianlimestones and mudstones interbedded with volcanic rocks (San-tos, 1999; Martınez, 2003).

Cretaceous rocks of southwestern Puerto Rico are dominated

596 JOURNAL OF PALEONTOLOGY, V. 80, NO. 3, 2006

FIGURE 5—Morphology of various tetraclone lithistid desmas obtained as loose spicules by etching the sponge-bearing limestone; these belonged toat least two or three different species (and genera), compare 1 and 2 for example. 1–5, ZPAL Pf. 16/st.590/17, 19, 14, 13, 18; 6, ZPAL Pf. 16/st.566/10. Scale bars 200 �m.

by volcanic and volcaniclastic facies, reflecting the back-arc set-ting of this depositional basin and proximity to active Cretaceousvolcanic centers. Large-scale tectonic activity and rapid volcani-clastic sedimentation prohibited stabilization of structural plat-forms and carbonate sedimentation during much of the island his-tory. But relatively short intervals of carbonate platform and slopedevelopment occurred episodically, commonly associated withlimited reef growth. The last of the carbonate depositional epi-sodes during the Late Cretaceous resulted in the deposition of theEl Rayo Formation (Santos, 1999).

The El Rayo Formation is composed of basaltic to andesiticvolcanic flows interbedded with volcaniclastic conglomerates,sandstones, and limestones (Slodowski, 1956; Mattson, 1960;Volckmann, 1983; Santos, 1999; Martınez, 2003). The limestoneunits are massive to bedded lenses interbedded with volcaniclasticbreccias, conglomerates, and sandstones. The limestones as rep-resent a carbonate platform sequence deposited over a volcanicsurface during a Maastrichtian transgressive event and are dividedinto four environmental facies based on rudist-bearing limestones:1) nearshore transgressive; 2) lagoonal; 3) shelf margin; and 4)slope (Santos, 1999; Martınez, 2003).

The fossil sponges described herein were found in a light gray-ish limestone of the El Rayo Formation slope suite on the SabanaGrande Quadrangle (Fig. 1.2) (Martınez, 2003). The sectionwhere the sponges were found is 38.1 m thick (Fig. 2). Theselimestones are thin to medium bedded where the skeletal frag-ments are composed of calcareous algae, gastropods, and benthicforaminifera. The bedded limestones are composed of sequencesof yellowish tan to light gray, interbedded mudstones, wacke-stones, and packestones with minor intercalated grainstones (Mar-tınez, 2003). The packestones and grainstones are commonlycomposed of benthic foraminifera and fragments of calcareous

algae, rudistids, echinoderms, gastropods, corals, and oysters. Vol-canic clasts are occasionally present in the grainstones, making10% of the composition of the rock (Martınez, 2003). The spong-es are found in the middle of the section with Unit 11 presentingthe greatest abundance (Fig. 2). Sponges are found in an uprightposition and as clusters of 5–20 specimens; in between suchsponge groups are densely packed ‘‘conglomerates’’ consisting ofsponge fragments of various sizes.

MATERIAL

Most of the sponges (seven more or less complete specimensand numerous broken fragments) have been obtained by dissolv-ing a large block of limestone in acid and most are heavily sec-ondarily silicified; the only nonsilicified specimen has been col-lected directly in the field. The calcareous specimen has nosiliceous spicules preserved and shows only gross morphology.The silicified specimens also show a general sponge morphologyand canalization. Polished slabs of the rock show that, in mostcases, silicification occurs in the inner part of the sponge whilethe outer zone, usually thick, presents a calcareous preservation.In some rare cases spicules may be observed on the surface ofthe silicified portion of the sponge, but usually the process ofsilicification obliterates their shape. In many cases only fragmentsof sponges are preserved, clearly indicating a common breaking(Fig. 3). Lithistids, usually found as entire specimens, are stronglysilicified, with spicules very poorly preserved (Fig. 4). Hexacti-nellids, on the contrary, only occur as small fragments and/orwell-preserved fragments of the choanosomal dictyonal skeleton(Fig. 7). This preservation type only allows their approximatedetermination to a high taxonomic level.

Repository.⎯All the investigated material (collection number

597PALEONTOLOGICAL NOTES

FIGURE 6—Dicranoclone lithistid desmas (in various views) obtained as loose spicules by etching the sponge-bearing limestone in acid. These belong,most probably, to a single species. 1, 4, 6, ZPAL Pf.16/st.590/3, 8, 4; 2, 3, 5, 7, 8, ZPAL Pf.16/st.566/2, 1, 9, 10, 3. Scale bar 200 �m.

ZPAL Pf.16) is housed in the Institute of Paleobiology, PolishAcademy of Sciences, Warszawa, Poland.

SPONGE DESCRIPTIONS

Classification of sponges is based on its spicules and morphol-ogy combined. In the case of the studied material, well-preservedspicules are only found loose, while entire sponges have verypoorly preserved spicules. In general, we were not able to relatereliably loose, relatively well-preserved spicules with specimensdisplaying complete morphology and vice versa. For this reasonno formal description or formal names are given, and sponges aredetermined only to the family or even higher taxonomic level.Based on small indeterminate fragments associated with wholesponges, we may assume that the diversity of lithistid spongeswas much higher than those described below. For details ofsponge taxonomy, see Hooper and Van Soest (2002).

Lithistid sponges.⎯Lithistid sponges are polyphyletic groupsof sponges characterized by having a choanosomal skeleton com-posed of more or less irregular articulated spicules called desmas(see Pisera and Levi, 2002).

Rhizomorine lithistid sponges: These sponges are characterizedby choanosomal desmas called rhizoclones (Pisera, 2002; Piseraand Levi, 2002). Rare, loose, and poorly preserved rhizoclones,and one small platelike sponge fragment displaying a fibrous skel-eton composed of rhizoclone desmas, have been found. No moreprecise determination is possible for such material.

Tetraclone bearing lithistids: There are two lithistid families thatare characterized by the presence of tetraclone desmas, and theydiffer, among others, in the type of ectosomal spicules (dichotria-enes vs. phyllo to discotriaenes) (Pisera, 2002; Pisera and Levi,2002). We were not able to find ectosomal spicules necessary fortheir determination, neither in situ nor as loose material, thus moreprecise determination is also not possible. To this group of spong-es belongs most of the whole specimens that are relatively wellpreserved. Apart from the whole sponges, we have found abun-dant loose tetraclones (Fig. 5), which belong to at least two dif-ferent species.

The most common is a large (Fig. 4.1–4.3), up to at least 12cm high and 5.5 cm long (all specimens are broken), tubular

598 JOURNAL OF PALEONTOLOGY, V. 80, NO. 3, 2006

FIGURE 7—Hexactinosid and lychniscosid skeletal fragments obtained by etching the sponge-bearing limestone in acid. 1–3, Outer surface of thechoanosomal skeletons. 1 and 2 belong to the same species, while 3 represents different species; 4–7, inner part of choanosomal skeletons; 8,fragment of the lychniscosan choanosomal skeleton, one lychnisc arrowed. 1, 8, ZPAL Pf.16/st.566/8, 17; 2, 4, 5, 7, ZPAL Pf.16/st.592/2, 5, 1, 4;3, 6, ZPAL Pf.16/st.590/1-2. Scale bars 1, 7, 1 mm; 2–6, 500 �m; 8, 200 �m.

599PALEONTOLOGICAL NOTES

sponge, with deep (piercing entire sponges) spongocoel measur-ing about 1–2 cm in diameter with a wall up to 1.8 cm thick. Thewall is pierced by a system of simple radial canals, which openon both surfaces; the diameter of the canals and their openingsvery between 0.2 mm up to 1 mm. These canal openings arerandomly distributed on the outer surface, while on the surfaceof a spongocoel they are distributed in irregular vertical rows andare visibly larger than in the outer surface. In some specimenspoorly preserved tetraclone desmas may be observed, but no ec-tosomal spicules were noted. Our specimens resemble, in mor-phology and canalization, the Late Cretaceous genus PhymatellaZittel, 1878, especially the species P. intumescens (Roemer, 1864)(see Zittel, 1878; Schrammen, 1910–1912), but absence of theectosomal spicules as well as very poorly preserved tetraclonesmake reliable identification difficult. These sponges also resem-ble, in morphology, the Late Cretaceous Jerea? sp., a very poorlypreserved sponge without spicules described by Thomas (1935)from Trinidad.

Different from the above, another lithistid with tetraclone des-mas is up to 4 cm long, with a very narrow and deep spongocoeland osculum surrounded with sinuous more or less radially ar-ranged surface canals (Fig. 4.5). Small canal openings (0.5 mmwide) occur on the rest of the surface. This sponge may alsobranch.

Another sponge with tetraclone desmas is represented in ourmaterial by small (up to 3 � 2 cm large) platelike fragments. Itsdesmas are strongly tuberculated. No other details can be ob-served, thus identification is impossible.

Corallistid sponges: They are characterized by choanosomal des-mas called dicranoclones (Pisera, 2002; Pisera and Levi, 2002).Only loose dicranoclones have been found (Fig. 6), and no wholesponge can be correlated with them. Spicule morphology is sim-ilar as in several Cretaceous genera, especially SchrammeniellaBreistroffer, 1949 (�Iouea de Laubenfels, 1955), but no preciseidentification is possible with this material.

Undeterminable lithistid: This is a small, about 6 cm high and 3cm wide (at the top), conical sponge (upper portion broken off,thus without a doubt larger). Its surface bears large openings (os-cula?), 3–4 mm in diameter, which are distributed evenly butwithout any order (Fig. 4.4). Much smaller canal openings, about0.1–0.4 mm wide, are dense but without any distributed order onthe surface. This sponge is entirely silicified and no spongocoelis visible, but it can be a secondary effect of chertification. Be-cause of heavy silicification, only vague traces of original spic-ules, which seem to be of desmas type, are preserved. No moreprecise identification of this sponge could be done.

Hexactinellid sponges.⎯Hexactinellid sponges are character-ized by having skeletons composed of hexactine (or their deriv-atives) spicules, either loose or fused in some groups.

Hexactinosid sponges: These are characterized by a choanosomalskeleton composed of fused hexactines forming dictyonal strands(Krautter, 2002; Reiswig, 2002; Tabachnik and Reiswig, 2002).In the studied material only small fragments of the dictyonal skel-eton, that differ in morphology (Fig. 7), have been observed.These differences of the outer surface of the choanosomal skel-eton (compare Fig. 7.1, 7.2 with Fig. 7.3) indicate the presenceof two different species in our material. There are also differencesbetween fragments of the choanosomal skeleton from the interiorof the sponge, but such differences may result from the fact theywere located in various parts of the sponge (Fig. 7.4, 7.7).

Lychniscosid sponges: These are sponges having hexactines in theform of lychniscs (Reiswig, 2002; Tabachnik and Reiswig, 2002).Very few poorly preserved fragments were found in this study(Fig. 7.8).

CONCLUSIONS

The Late Cretaceous deposits of El Rayo Formation in PuertoRico contain a rich fauna of siliceous sponges composed of bothlithistids (tetraclone-bearing forms, rhizomorines, and corallistids)and hexactinosid hexactinellids. Lychniscosid sponges, althoughpresent, are very rare. Most sponges are heavily secondarily si-licified (chertified); silicification preserved only gross details, andspicules are rare and poorly preserved. They occur in heavilychertified limestones deposited in slope environments in an island-arc setting, resembling in this aspect lithistid occurrences todayin the same region, which are common on slopes of the Carribeanislands (Van Soest and Stentoft, 1988; Maldonado and Young,1996). The sponge assemblage found, in general, is similar to thatknown from the Upper Cretaceous of Europe, but most Europeansponge faunas (Hinde, 1883; Schrammen, 1910–1912) occur inchalk or even more shallow-water epicontinental deposits, or asthose described by Moret (1926) from France, in the flysh se-quence. Our finds and earlier reports (Thomas, 1935; Howell,1966) indicate that extent of the Late Cretaceous facies rich insponges was larger then reported so far, and included the Carib-bean region.

ACKNOWLEDGMENTS

We would like to thank the reviewers, M. Krautter and J. Reit-ner, for their constructive comments that helped to improve themanuscript.

REFERENCES

BREISTROFFER, M. 1949. Note de nomenclature paleontologique: Spon-giaires Cretace. Bulletin de la Societe Scientifique du Dauphine, 62:103.

DE LAUBENFELS, M. W. 1955. Porifera, p. E21–E112. In R. C. Moore(ed.), Treatise on Invertebrate Paleontology, Pt. E. Geological Societyof America and University of Kansas Press, Lawrence.

HINDE, G. J. 1883. Catalogue of the Fossil Sponges in the GeologicalDepartment of the British Museum. London, 248 p.

HOOPER, J. N. A., AND R. W. M. VAN SOEST (EDS.). 2002. SystemaPorifera. Kluwer Academic/Plenum Press, New York, 1,708 p.

HOWELL, B. F. 1966. New Upper Cretaceous sponge from Puerto Rico.Journal of Paleontology, 40:207–209.

KRAUTTER, M. 2002. Fossil Hexactinellida: an overview, p. 1211–1223.In J. N. A. Hooper and R. W. M. Van Soest (eds.), Systema Porifera.Kluwer Academic/Plenum Press, New York.

LAMOUROUX, J. V. F. 1821. Exposition Methodique des Genres de l’Ordredes Polypiers. Paris, 115 p.

MALDONADO, M., AND C. M. YOUNG. 1996. Bathymetric patterns ofsponges distribution on the Bahamian slope. Deep Sea Research I, 43:897–915.

MANTELL, G. 1822. The Fossils of the South Downs, or Illustrations ofthe Geology of Sussex. London, 327 p.

MARTINEZ, M. 2003. Geologic and tectonic history of the eastern sectionof the Sabana Grande Quadrangle. Unpublished M.S. thesis, Universityof Puerto Rico, Mayaguez, 109 p.

MATTSON, P. H. 1960. Geology of the Mayaguez area, Puerto Rico. Geo-logical Society of America Bulletin, 84:319–362.

MORET, L. 1926. Contribution a l’etude des spongiaires siliceux du Cre-tace superieur francais. Memoires de la Societe Geologique de France,5:1–327.

PISERA, A. 1999. Postpaleozoic history of siliceous sponges with rigidskeleton. Memoirs of the Queensland Museum, 44:436–472.

PISERA, A. 2002. Fossil lithistids: an overview, p. 388–402. In J. N. A.Hooper and R W. M. Van Soest (eds.), Systema Porifera. Kluwer Ac-ademic/Plenum Press, New York.

PISERA, A., AND C. LEVI. 2002. ‘Lithistid’ Demospongiae, p. 299–301.In J. N. A. Hooper and R.W. M. Van Soest (eds.), Systema Porifera.Kluwer Academics/Plenum Press, New York.

REISWIG, H. M. 2002. Order Lychniscosida Schrammen, 1903, p. 1377.In J. N. A. Hooper and R. W. M. Van Soest (eds.), Systema Porifera.Kluwer Academic/Plenum Press, New York.

600 JOURNAL OF PALEONTOLOGY, V. 80, NO. 3, 2006

REUSS, A. E. 1846. Die Versteinerungen der Bohemischen Kreidefor-mation. Stuttgart, 148 p.

ROEMER, F. A. 1864. Die Spongitarien des Norddeutschen Kreide-Gebir-ges. Theodor Fisher, Kassel, 62 p.

SANTOS, H. 1999. Stratigraphy and depositional history of the UpperCretaceous strata in the Cabo Rojo-San German structural block, south-western Puerto Rico. Unpublished Ph.D. thesis, University of Coloradoat Boulder, 184 p.

SCHELLEKENS, J. K. 1998. Composition, metamorphic grade and originof metabasites in the Bermenja Complex, Puerto Rico. InternationalGeology Review, 40:722–747.

SCHELLEKENS, J. H., H. SANTOS, C. C. ALMY, AND P. JANSMA. 1993.Field Guide to the 12th Symposium of Caribbean Geology. Universityof Puerto Rico, Mayaguez, 65 p.

SCHRAMMEN, A. 1910–1912. Die Kieselspongien der oberen Kreide vonNordwestdeutschland. Palaeontographica Supplement, 5:1–385.

SLODOWSKI, T. R. 1956. Geology of the Yauco area, Puerto Rico. Un-published Ph.D. thesis, Princeton University, Princeton, New Jersey,130 p.

TABACHNIK, K. R., AND H. M. REISWIG. 2002. Dictionary of Hexacti-nellida, p. 1224–1229. In J. N. A. Hooper and R. W. M. Van Soest(eds.), Systema Porifera. Kluwer Academic/Plenum Press, New York.

THOMAS, D. H. 1935. On some sponges and a coral of Upper Cretaceousage from Toco Bay, Trinidad. Geological Magazine, 72:175–179.

TRECHMANN, C. T. 1935. Fossils from the Northern Range of Trinidad.Geological Magazine, 72:166–175.

VAN SOEST, R. W. M., AND N. STENTOFT. 1988. Barbados deep-watersponges. Studies on the Fauna of Curaco and other Caribbean Islands,70:1–175.

VOLCKMANN, R. P. 1983. Upper Cretaceous stratigraphy of southwestPuerto Rico. In Stratigraphic notes 1983. U.S. Geological Survey Bul-letin, 1537-A:A73–A83.

WIEDENMAYER, F. 1994. Contribution to the knowledge of post-Paleozoicneritic and archibenthal sponges (Porifera). Schweizerische Palaonto-logische Abhandlungen, 116:1–147.

ZITTEL, K. A. 1878. Studien uber fossile Spongien. Zweite Abteilung:Lithistidae.-Abhandlungen der Konigliche bayerischen Akademie derWissenschaften, Mathematisch-Physische Klasse, 13:66–153.

ACCEPTED 18 MARCH 2005