December 2004 CainozoicResearch, 3(1-2), pp. 135-141, In: Donovan, S.K. (ed.). The Mid-Cainozoic White Limestone Group ofJamaica The nautiloid Aturia (Mollusca, Cephalopoda) in the Mid-Cainozoic of Jamaica and Carriacou Roger+W. Portell¹, Stephen+K. Donovan² & Ron+K. Pickerill³ 1 Florida Museum ofNaturalHistory, P.O. Box 117800, University ofFlorida, Gainesville, Florida 32611-7800, USA; e-mail:[email protected] department ofPalaeontology, NationaalNatuurhistorisch Museum, Postbus 9517, NL-2300 RA Leiden, The Netherlands; e-mail: Donovan@naturalis. nnm.nl department of Geology, University ofNew Brunswick, Fredericton, New Brunswick, Canada E3B 5A3; e-mail: [email protected] Received 3 January2003; revised version accepted 11 April 2003 Recent collections in Jamaica and Carriacou have of the nautiloid fossil in the Antilles. Hith- yielded new specimens Aturia, a rare not erto, many of these specimens have been described or illustratedand those derived from the MiddleMiocene Grand Bay Forma- tion of Carriacou represent the youngest nautiloids now known from the Caribbean. Additionally, stratigraphic nomenclature pro- vided for some previously reported Jamaica and Carriacou Aturia is herein revised to better place these very uncommon fossils in their context. proper lithostratigraphic KEY WORDS:Aturia, Cephalopoda,Jamaica, Carriacou, Eocene, Miocene. Introduction Miocene? A. cubaemis did not differ greatly from simi- lar-sized A. alabamensis, commonly found in the Eocene Nautiloids are rare fossils in the Cainozoic of the Ameri- of the southeastern United States. He also suggested that cas, including the Caribbean. Nautiloids occur from the the Eocene A. panamensis and A. peruviana might be Paleocene to Miocene of the Antillean but and noted the close of both region, are conspecific, similarity spe- unknown from younger deposits (Schmidt & Jung, 1993, cies to typical representatives of A. alabamensis. Jung table that reflects the decline of this the Miocene curvilineata in 1), a pattern global (1966) placed A. synonymy that time with the Miocene cubaensis. group at (Miller, 1947, 1949; Kummel, 1964, A. Clearly, specific place- fig. 280). Teichert (1986, p. 234) noted that, ‘... no re- ment of Aturia fossils is problematic, with their indiffer- mains of nautiloids had been from ever reliably reported ent preservation, and nominal species being based on rocks of Pliocene or Pleistocene age anywhere in the juveniles or the remnants of more mature individuals world.’ Indeed, apart from rare loliginid statoliths (Furnish & Glenister, 1987; Chirat, 2000; R.A. Hewitt, fossil (Clarke & Fitch, 1975, 1979), cephalopods are written comm.). Our new material from the Lower Mio- unknown from the Plio-Pleistocene of the Antillean re- cene Montpelier Formation (White Limestone Group) of gion. Jamaica, and the Middle Miocene Grand Bay Formation Caribbean nautiloidsattributable to the genus Aturia of Carriacou are similarly difficult to include in nominal have been from the Eocene of with confidence. Chirat Bronn, 1838, reported species (2000) made an elegant Panama and the Colombia, Jamaica, Venezuela, Oligo- argument that the global diversity of Aturia may be in- cene of Cuba and Puerto Rico, and the Miocene of Car- flated due to geographically separated and indifferently Trinidad and Vene- different riacou, Cuba, Jamaica, Martinique, preserved specimens being given names, when zuela (Miller, 1947; Jung, 1971; Schmidt & Jung, 1993; they represented widely drifted shells of but a few spe- Donovan et al., 1995). Four nominal species of Aturia cies (in contrast, taphonomic evidence from shells at have been from the A. localities local reported Caribbean; peruviana some suggests they are mortalities of ju- A. cubaensis Olsson, 1928, panamensis Miller, 1947, A. veniles; R.A. Hewitt, written comm.). This formed part (Lea, 1841), and A. curvilineata Miller & Thompson, of Chirat’s argument for the necessity of a thorough 1937. However, the of these conchs taxonomic revision of the systematic position genus. In consequence, we is below the level. consider it very problematic generic For exam- conservative to place all of our specimens Miller considered that the of from Jamaica and Carriacou in nomenclature ple, (1947, p. 92) holotype open as - 136- Specimen Locality Formation Aturia A* sp. A* NMB J 31311 NMB 1089710897 Troy Formation B+ Aturia sp. UF 3881338813 UFXJ015 MontpelierFormation UF 6842268422 UFXJ015 MontpelierFormation UF 6842768427 UFXJ015 MontpelierFormation UF 6843668436 UFXJ015 Montpelier Formation UF 107841 UFXJ015 MontpelierFormation * Table = 1. Aturia sp. from the White Limestone Group of Jamaica. Key: see Schmidt & Jung(1993, text-fig. 1) for locality map Claremont Formation this is the Formation (although originally reported as (Jung, 1971), outcrop now part Troy (Mitchell, + = Donovan 2004)), see (1995, fig. 1.2) for locality map. Specimen NMB Locality Formation Aturia C Aturia sp. C NMBJNMB J 32964 10793,northnorth of Kendeace Pt. Kendeace Formation NMB J 32965 13759, west ofKendeace Pt. Kendeace Formation NMBJNMB J 32966 13759,west ofKendeace Pt. Kendeace Formation D Aturia sp. UF 108574108574 10730, Point St. Hilaire Grand Bay Formation(tuffaceous facies) UF 108575108575 10707,north of Tarleton Pt. Grand Bay Formation (tuffaceous facies) UF 112028 10707,north of Tarleton Pt. Grand Bay Formation(tuffaceous facies) UF 112029 10708, Tarleton Point Grand Bay Formation (tuffaceous facies) UF 112030 10723,north of Tarleton Pt. Grand Bay Formation (sandy facies) UF 104796104796 10804,northof Pt. Saint Hilaire# Basal Grand Bay Formation Table 2. Aturia sp. from the Miocene ofCarriacou, The Grenadines. See Jung(1971, text-fig. 1) for locality map. Key: # = this lo- cality was consideredby Jung(1971) to be Kendace Calcareous Silt Member, but it is now consideredto be the basal member of the Grand Bay Formation (Donovan el al., 2003). A to while that of most that this collected from Aturia sp. D, recognising some our probable specimen was species may subsequently be shown to be synonymous if what is now the mid Lower to mid Middle Eocene Yel- superior specimens become available. low Limestone Group, in which nautiloids are more di- All discussed herein in the & specimens are reposited verse (Schmidt Jung, 1993; Donovan et al., 1995; Naturhistorisches Museum, Basel (NMB) or the Florida Donovan & Draper, 2001). Jung (1972, table 1) and of Natural of Schmidt recorded Museum History, University Florida, & Jung (1993, pp. 349, 351, fig. 4.4) Gainesville of nomenclature of (UF). Our philosophy open only a single fragmentary specimen Aturia sp. from follows Bengtson (1988). the Eocene Claremont Formation (= Troy Formation from sensu Mitchell, 2004) and none are reported the Jamaican Oligocene. The youngest Caribbean nautiloids Jamaica are Miocene and in Jamaica are locally common in the Lower Miocene Montpelier Formation (Schmidt & Jung, The White Limestone Group of Jamaica, a unit exposed 1993, p. 349; Donovan et al., 1995, p. 589, figs 1.2-1.4). over more than half the island, has been studied and de- Specimens only occur in deep-water deposits on slide researchers for blocks derived from shallow-water the bated by numerous over 175 years (see, reefs, exposed at disused chalk of for example, De la Beche, 1827; Sawkins, 1869; Hill, large, quarry near Duncans, parish 1899; Trechmann, 1922; Hose & Versey, 1957; Versey, Trelawny. 1957; Zans et al., 1963; Wright, 1974; Robinson, 1994). Mitchell (2004) provided a revised lithostratigraphic Carriacou scheme for the White Limestone Group that we follow herein. The Miocene sedimentary geology of Carriacou was De la Beche (1827, p. 170) provided the earliest rec- described in detail by Robinson & Jung (1972), Speed et ord of a nautiloid. Nautilus, from his white limestone al. (1993) and Donovan et al. (2003); two of the four It formation (see also Miller, 1947, p. 10). is considered Miocene formations have yielded Aturia. - 137- Aturia Jamaica. Figure 1. spp. from the WhiteLimestone Group, 1 - Aluria NMB J Eocene sp. A, 31311 (Middle Troy Formation), right lateral view of incompletephragmocone (internal mould), x 1. - Aturia UF lateral view of RTV 2-5 sp. B, 107841 (Lower Miocene Montpelier Formation), right (2) silicone rubber peel taken from incomplete external mouldof phragmocone; posterior view (3) ofinternal mould; apertural view (4) of internal mould; left lateral view (5) ofinternal mould.All x 1.5. All specimens photographed uncoated. The recommendationof Stridsberg (1990), to illustrate cephalopod shells in their presumed life position, has been followedherein. - 138- The Kendeace Formation rests unconformably on the ity between NMB J 31311 and Eocene A. alabamensis Lower? Miocene Belmont Formation (Donovan et al., figured in Miller (1947, pi. 58), but, given the incom- 2002, fig. 3). The Kendeace Formation is conglomeratic plete condition of the internal mould, they determined in with included clasts of but is that identification unwarranted. part, igneous origin, pri- specific was This speci- siltstone unit horizons. marily a containing limestone men is also close to A. panamensis Miller (R.A. Hewitt, This formation is discontinuous above the Belmont For- written comm.). mation (Speed et al., 1993), grading upwards into limestones of the Middle Miocene Carriacou Formation. The Grand Formation is the Miocene Bay highest unit, Aturia sp. B but is conformable the not on Carriacou Formation Figure 1/2-5 (Donovan et al., 2003). The formation consists mainly of volcaniclastic sandstones and