Contr. Tert. Quatern. Geol. 35(1-4) 95-111 2 pis. Leiden, April 1998 Holoplanktonic Mollusca (Gastropoda: Heteropoda and Thecosomata) from the Pliocene Bowden beds, Jamaica Arie W. Janssen XEWKJJA (GOZO), MALTA Janssen, Arie W. Holoplanktonic Mollusca (Gastropoda: Heteropoda and Thecosomata) from the Pliocene Bowden Beds, Jamaica.In: Donovan, S.K. (ed.). The Pliocene Bowden shell bed, southeast Jamaica. — Contr. Tert. Quatern. Geol., 35(1-4): 95-111, 2 pis. Leiden, April 1998. of Jamaica. Two Three Heteropoda and 14 Euthecosomata (‘Pteropoda’) species are recorded from the Pliocene (Piacenzian) Bowden, Heteropoda, four species of Limacinidae and Clio aff. braidensis (Bellardi, 1873) have not been recorded previously from Bowden. followed of the for Cavolinia ventricosa Systematic descriptions are by a brief discussion on the age assemblage. Lectotypes are designated (Guppy, 1882) and Diacria digitata (Guppy, 1882). Key words — Bowden, Jamaica, Heteropoda, Thecosomata, Pteropoda, Pliocene, systematics, biostratigraphy. A.W. Janssen, Nationaal Natuurhistorisch Museum, P.O. Box 9517, NL-2300 RA Leiden,The Netherlands; or: 12, Triq il-Hamrija, Xewkija VCT 110, Gozo, Malta. Contents PectinibranchiataHeteropoda Atlanta (Atlanta) diamesa Woodring Atlanta lissa Woodring Introduction p. 95 (Atlantidea) methods localities 96 Material, and p. discussed detail Collins The pteropods were in by Abbreviations p. 96 (1934, 155), who listed the following nine species and Age of the Bowden shell bed p. 97 p. also mentioned Atlanta one heteropod, sp. (Collins, 1934, Systematic palaeontology p. 97 146): Order Heteropoda p. 97 p. Order Thecosomata p. 99 Cavolinia telemus (Linne) Conclusions 104 p. Cavolinia ventricosa (Guppy) Acknowledgements p. 105 Cavolinia digitata (Guppy) References p. 105 Cavolinia vendryesiana (Guppy) Diacria bisulcata Gabb Cleodora bowdenensis Collins Introduction Styliola sulcifera Gabb Creseis acicula Rang The classic and renowned shell bed of Bowden (Jamaica) Collins Various Bowdenatheca jamaicensis has been the subject of numerous publications. authors have described the molluscan faunas from this In addition to the genus Bowdenatheca and its type deposit, from the nineteenth century onwards, culminating species, B. jamaicensis, Cleodora bowdenensis was erected in W.P. Woodring's monographs (1925, 1928). Woodring by Collins (1934), who distinguished an 'upper' and a mentionedthe of (1928, p. 113ff) following seven species 'lower' the latter the main shell bed from zone, being holoplanktonic gastropods from Bowden: which Woodring's molluscan materialoriginated. The three last-mentioned species in the above list came from the Pteropoda Thecosomata lower zone, all others from the upper zone. Cavolinia telemus (Linne) The bulk of the material studied for this paper is in shell Cavolinia ventricosa (Guppy) preservation and originates from sediments yielding abun- Cavolinia digitata (Guppy) dant benthic molluscan material, although a part of the Cavolinia vendryesiana (Guppy) samples show distinct signs of aragonite dissolution. It is Diacria bisulcata Gabb assumed that most of the material comes from the main 96 shell bed, or from close it. layers very to Same locality as PJ 464 (NMB locality 10831), PJ 669 The revision of present the Bowden holoplanktonic (NMB locality 11036), PJ 743 (NMB locality 11110). Leg. Mollusca comprises three species of Heteropoda and E. Robinson, Myrtle Haase, Alfred Rose, Richard de Souza fourteen pteropod species. and P. Jung, 12 May 1969. This sample comprises only a single specimen of Cavolinia digitata. MATERIAL, METHODS AND LOCALITIES Bowden shell bed, Sample 1-4. — Material housed in the Material studied for the Florida Museum ofNatural Gainesville present paper was largely (samples History, (Florida, 1-1 collected the Bowden shell bed Data follows: to 1-6) at type locality. U.S.A.). are as Bowden (XJ(X)2), Jamaica, St For and Thomas geographic lithostratigraphic data on this locality, parish. Pliocene, Bowden Formation, in situ. Coll. reference is made to Zans et al. (1963), Robinson (1969) Roger Portell, 28 May 1990. The material comprises nine and Pickerill et al. (1998). Details of the various samples, samples ofEuthecosomata, apparently picked from wash- the as known to author, are given below. ing residues. Finer fractions from the same sample received Reference material listed in the loan to systematic part below on appeared to yield no holoplanktonic molluscs. includes numbers only sample as defined here, specifying the number of specimens, and followed by registration Bowden shell bed, Sample 1-5. — Material collected by number (for example: sample 1-1/12 specimens, RGM 396 S.K. Donovan, donated to the RGM collections in Septem- 006). ber 1995. Label stating: Pliocene Bowden shell bed, SE Jamaica. The specimens were picked from washing resi- Bowden shell bed, Sample 1-1. — Material collected in dues, five species occur. Most, if not all, of this material is 1975 by Dr Jan P. Krijnen, housed in the RGM collections. from unit 2 of the Bowden shell bed sensu Pickerill et al. The is indicated locality as 'Bowden, road cut exposure, (1998). gully fill'. The material includes a large sample of benthic molluscs. The discussed herein Bowden shell 1-6. — On the author's holoplanktonics were bed, Sample request, recovered from sediment infillof shells. S.K. and larger gastropod Donovan R.W. Portell collected a quantity of Contrary to most other samples, the present sample yielded larger benthic gastropod shells at the Bowden type locality, molluscan material in excellent preservation, with hardly in order to recover holoplanktonics from their sediment dissolution. The of the is for 1-1. The collected in any aragonite quality specimens contents, as sample sample was very good and only this sample yielded small specimens, February 1996 and subsequently donated to the RGM. such as limacinids. Sample 1-1 is therefore considered to Unfortunately, almost all specimens appeared to have been the represent most complete holoplanktonic molluscan collected from a level of advanced decalcification. Most in assemblage, which the species occur in almost natural shells were partly to completely dissolved, and sediment ratios. infill had become indurated, forming internal moulds. Still, A 396 single specimen (RGM 032) in this sample, a a careful inspection of this material by breaking up the shellof Cavolinia large tridentata, is stated to have come moulds and study under the microscope, yielded quite a from 'a higher level.' This specimen has suffered from numberof holoplanktonics, but exclusively larger species. aragonite dissolution, being preserved as an internal mould Ten species are represented in this material. with shell remains only. Bowden Formation, Sample 2-1. — Sediment sample Bowden shell bed, Sample 1-2. -— Material housed in the collected by S.K. Donovan, subsequently donated to the Naturhistorisches Museum Basel (NMB, Switzerland) with RGM collections, September 1995, labelled: Bowden the following label: Jamaica, SE coast; Port Morant, Bow- Formation, from coastal section, stratigraphically above the den Fm, leg. Jooss and Strasser, 1931; don. Trinidad lease- shell bed. holds. The sediment is decalcified to a high degree and the few C.H. Jooss and Strasser originally sampled five locali- fossils are represented as moulds and casts, stained dark ties (partly indicated B.l to B.5) within the Bowden For- reddish brown. Identification of the material is difficult mation. However, detailed geographical data are lacking. because of poor preservation. Four species could be recog- All five localities are assumed to be situated east of Port nised. 2 in Morant, an area not larger than 200 m . This is NMB locality 10635. ABBREVIATIONS Bowden shell bed, Sample 1 -3. — Material housed in the The Naturhistorisches Museum Basel (NMB locality 11146), following abbreviations are used: carrying the following label: PJ 778. Jamaica, Bowden Shop, Bowden shell bed. Bowden Formation. Outcrop NMB Naturhistorisches Museum, Geology Depart- opened by bulldozer. 1:50,000sheet N; 1:12,500 sheet 235. ment, Basel (Switzerland). 97 material of this reference was studied RGM Nationaal Natuurhistorisch Museum (Palaeon- v the original by tology Department, Cainozoic Mollusca), Lei- the present author. den, The Netherlands (formerly Rijksmuseum van Geologie en Mineralogie). SMF Senckenberg Museum, Frankfurt am Main ORDER HETEROPODA (Germany). Ruthe UF Florida Museum of Natural History, University Family Atlantidae Wiegman & of Florida, Gainesville(U.S.A.). Genus Atlanta Lesueur USNM National Museum of Natural History, Smith- sonian Institution, Department of Paleobiology, Type species — Atlanta peroni Lesueur. Washington D.C. (U.S.A.). Atlanta diamesa Woodring, 1928 PI. 1, Fig. la-c AGE OF THE BOWDEN SHELL BED v* 1928 Atlanta (Atlanta) diamesa, new species, Woodring, shell bed the of 133, figs 23-25. In the classic literature on the Bowden age p. these deposits is mostly considered to be Miocene. Recent material — and two research, however, has demonstrated them to be of a Type Holotype (USNM 369335) from Jamaica' poorly preserved paratypes 'Bowden, (Al- younger age. Collection). Aubry (1993) and Berggren (1993) discussed the drich/Johns Hopkins —The shell has distinct lenticular with biostratigraphy of Neogene deposits in eastern Jamaica in Description a shape double-walled that is broken detail, using calcareous nannofossils and planktonic fora- originally a peripheral flange, The for the The ratio is c. 0.29. minifera,