Echinoderms of Pliocene Bowden Shell Southeast Jamaica

Echinoderms of Pliocene Bowden Shell Southeast Jamaica

Contr. Tert. Quatern. Geol. 35(1-4) 129-146 1 fig., 1 table, 4 pis. Leiden, April 1998 Echinoderms of the Pliocene Bowden shell bed, southeast Jamaica Stephen K. Donovan UNIVERSITYOF THE WEST INDIES KINGSTON, JAMAICA AND Christopher R.C. Paul UNIVERSITY OF LIVERPOOL LIVERPOOL, ENGLAND Donovan, Stephen K. & Christopher R.C. Paul. Echinoderms of the Pliocene Bowden shell bed, southeast Jamaica. In: Donovan, S.K. (ed). The Pliocene Bowden shell bed, southeast Jamaica.— Contr. Tert. Quatern. Geol., 35(1-4): 129-146,1 fig., 1 table, 4 pis. Leiden, April 1998. The the of unit in echinoderm fauna of late Pliocene Bowden shell bed of southeast Jamaica is more diverse than that any coeval the echinoderm have been identified from the Bowden shell bed: asteroid Caribbean. The following taxa goniasterid or astropectinid sp. indet., indet., and the echinoids Eucidaris diadematid indet.,Arbacia Echinometra ophiuroid sp. madrugensis (Sánchez Roig, 1949), sp. sp., sp., cf. indet. and indet. Adult echinoids Tripneustes sp., Clypeaster carrizoensis Kew, 1914, scutelline sp. spatangoid sp. are invariably tests have because of their low volume them less preserved as fragments; juvenile may survived to surface area ratio, making prone to mechanical collapse. At the ordinal level, Eucidaris - diadematoid- Echinometra - arbaciid - toxopneustid - Clypeaster - scutelline - spatangoid echinoid faunas seem to have been the norm in the Caribbean during the Pliocene. Echinoids across the Pliocene-Pleistocene in the Caribbean follow similar of faunal that ofbenthic molluscs. interval region may a pattern turnover to Key words — Bowden shell bed, Pliocene, Echinodermata, Asteroidea, Ophiuroidea, Echinoidea. S.K. Donovan, Department of Geology, University of the West Indies, Mona, Kingston 7, Jamaica; C.R.C. Paul, Department of Earth Sciences, University of Liverpool, P.O. Box 147, Liverpool, L69 3BX, England. Contents species of asteroid, an ophiuroid, plus at least eight species of echinoid, making it the most diverse Pliocene echino- derm known from the Antillean Introduction p. 129 assemblage region (Dono- van & Paul, Systematic palaeontology p. 130 1996). The echinoids of the Pleistocene deposits of eastern Discussion p. 134 Jamaica have been documented in detail et al., Acknowledgements p. 135 (Donovan References 135 1994b; Donovan & Portell, 1996; Donovan & Embden, p. 1996) and this analysis is extended into the Pliocene herein. Prior to the account of Donovan & Paul (1996), the only of fossil echinoid Introduction report a from Bowden was by Weisbord who noted that, 'In the late Miocene (1969, p. 309), [Echi- The known echinoid fauna of the Pliocene of Jamaica is nometra] lucunter is reported from Bowden, Jamaica.' (The sparse (Donovan, 1993). Donovan & Paul (1996) have Bowden Formationwas previously dated as Miocene; see This has been recently augmented this fauna, otherwise based mainly on Donovan, 1998). specimen(s) not located by it if it reports of more or less complete tests, in a preliminary S.K.D. However, remains uncertain truly came from the Bowden shell bed the Bowden report ofthe moderately diverse echinoderms from the late or even Formation. For Pliocene Bowden shell bed of southeast Jamaica, the fauna comparison, Caldwell (1966) recorded a needlefish jaw of which re-identified the claw of is largely disarticulated. The purpose of the (subsequently as a callianassid W.C. Blow in Clarke & Fitch, present paper is to document fully the fauna of the Bowden crustacean; 1979), purport- shell which is from the Bowden but the of the bed, now known to consist of at least one edly Formation, description 130 shows it have been collected from locality to an overlying data). The first Pliocene asteroids known from the island unit, either the Old Pera beds (early Pleistocene) or the Port are from the Bowden shell bed. Morant Formation (late Pleistocene). Prior to Robinson's The precise taxonomic assignment of this small collec- (1969) definition of the Bowden Formation sensu stricto, tion of marginal ossicles is problematic. The specimen all of these units in 'Miocene' were 'lumped together' a figured by Donovan & Paul (1996) appears to be a typical Bowden Series (E. Robinson, pers. comm.). It should be astropectinid superomarginal (compare with specimens noted that tests ofEchinometra, assigned to E. viridis A. figured by Blake, 1973; J.W.M. Jagt, written comm.). With and Echinometrai? Agassiz, 1863, sp., occur in the basal one possible exception, all of these specimens could con- conglomerate of the Port Morant Formation (Donovan et ceivably have been derived from a single species. The al., 1994b). It is considered at least possible, perhaps figured specimen shows the typical facet morphology of these ossicles. probable, that this is the horizon which yielded Weisbord's Externally they are all smooth and unsculp- at E. lucunter (Linne, 1758). tured or, in least one example (EE 5214[1]), perhaps The is Specimens used in the present study are deposited in the weakly pitted. only exception the biggest specimen in lot EE which is broad with collections of the Natural History Museum, London 5237, a weak, pustular exter- (BMNH EE 5209-EE 5230, all SEM stubs; and EE nal sculpture, the largest pustules being concentrated to the and distal facets. This indi- 5237-EE 5246) and the Florida Museum of Natural His- adjacent proximal may the of second until tory, Gainesville (UF 67426-67437, 71283). Descriptive cate presence a species, but, more terminology of the echinoderm test follows Gale (1987a), specimens are available, it is considered conservative to Melville & Durham (1966), and Durham & Wagner (1966). include all ossicles in one species under open nomencla- The classification of echinoids is that of Smith (1981, ture. 1984) and Smith & Wright (1993). Synonymy lists include Asteroids are unknown from the Jamaican Pleistocene. Two Recent known from the island reported occurrences in Jamaica only. Plates 1-4 illustrate astropectinids are recorded from bottoms. specimens sputter coated with 60% gold-palladium and Astropectensandy Notably, dupli- 1840 favours 'Soft examined using a Leica 440 scanning electron microscope catus Gray, (1-550 m water depth) All BMNH sediment of sand shell hash' (SEM). specimens were processed from bulk composed or (Hendler et at., from unit 2 of the Bowden shell bed substrate for samples (sensu Pick- 1995, p. 73), suggesting a possible preference the in the Bowden shell erill el al., 1998) unless otherwise stated. All specimens are species preserved bed. from the Bowden shell bed unless indicated otherwise. Class Ophiuroidea Gray, 1840 SYSTEMATIC PALAEONTOLOGY Incerti ordinis indet. Class Asteroidea de Blainville, 1830 Ophiuroid sp. PI. 8 Subclass Neoasteroidea Gale, 1987b 1, Fig. Family Astropectinidae Gray, 1840 or 1996 vertebral ossicles. — Donovan & Paul, GoniasteridaeForbes, 1841 Ophiuroid table 1. p. 166, Asteroid sp. indet. Material— A vertebral BMNH EE 5212. PI. 1, Fig. 2 single ossicle, Remarks — Like asteroids, no complete fossil ophiuroids — known from the Jamaican rock record. Disarticulated 1996 Astropectinid or goniasterid. Donovan & Paul, are p. 166, fig. 1G, table 1. vertebral ossicles have been recorded from the Oligocene and Pleistocene of the island (Donovan et al., 1993; Dixon Material, localities and horizons — Thirteen from marginal et al., 1994); they are also known the Miocene (R. W. ossicles from the Bowden shell bed: BMNH EE 5213(1-4], Ported, pers. comm.). The Bowden vertebra differs from EE and BMNH EE EE those 5214(1-3] 5237(1-6], 5213(1] was previously described from Jamaica in having a strep- illustrated by Donovan & Paul (1996). A further ossicle, tospondylous, hourglass-shaped, 'ball-and-socket' articula- BMNH EE 5238, collected from the Bowden Forma- tion was (G. Hendler, written comm.; compare with, for exam- tion at section 5 of Pickerill et al. towards the (1998), top ple, Mortensen, 1933, fig. 2). Smith et al. (1995, p. 236) of the formationand 1 below the micritic over m prominent noted this type of articulation in the Ophiocanopidae, limestone horizon. Ophiobyrsinae, Hemieuryalinae and the euryalid groups. In Remarks — No fossil asteroids have been found complete the extant Caribbean shallowerwater fauna, these groups in the Jamaican rock but disarticulated record, marginal are mainly represented by gorgonocephalids and hemieury- ossicles Previous have are locally common. reports men- alids (Hendler et al., 1995). tioned specimens from the Upper Cretaceous, Eocene and Oligocene (Donovan et al., 1993; Dixon el al., 1994); they are also known from one Miocene locality (S.K.D., unpubl. Class Echinoidea Leske, 1778 131 Subclass Cidaroidea Claus, 1880 fig. ID, table 1. 1996 Indeterminate diadematoid.— Donovan, 35, Order Cidaroida Claus, 1880 p. fig. IB. Family Cidaridae Gray, 1825 in Diadematoid.— Donovan, fig. 6.12D. Genus Eucidaris Pomel, 1883 pr. Material— 27 spines, UF 67433 (19 spines), BMNH EE 5216[l-7], EE 5229[2]; and one test plate, BMNH EE Eucidaris madrugensis (Sánchez Roig, 1949) 5210[ 1]. PI. 1, Figs 1, 5-7, 9 Remarks — Diadematoids in the Bowden shell bed are represented by fragments of spines and rare test fragments, 1996 Eucidaris madrugensis (Sanchez Roig). — Donovan but there is little of these further & table 1. prospect classifying Paul, p. 166, fig. 1C, without material Gordon, However, 1996 Eucidaris madrugensis (Sanchez Roig). — Donovan, superior (C.M. 1990). 1A. the nature of the diadematoidtest the p. 35, fig. precludes possibility in Eucidaris — that will be in the turbidite pr. madrugensis (Sanchez Roig). Donovan, they preserved deposits (Picker- fig. 6.12B. ill et al., 1998) of the Bowden shell bed (Greenstein, 1991; Donovan & Gordon, 1993). Although unknown from Material— 89 spines, UF 67434 (52 spines), BMNH EE articulated specimens in the Jamaican fossil record, the 5211 1 EE EE BMNH EE diadematoids known from the [ -4], 5229[1], 5230[l-4], distinctive spines of are now 5246f 1 -28]; a genital plate (madreporite), BMNH EE early Palaeocene (Donovan & Veltkamp, 1992), late Plio- 1 and 10 test BMNH EE 5218[ ]; plates/test fragments, cene, early Pleistocene (Donovan et al., 1994b; Donovan & 5219[ 1 -3], EE 5245[l-7].

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