Lusks from Trinidad
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A PLIOCENE MOLLUSCAN FAUNULE FROM TRINIDAD PETER JUNG NATUHI-IISTORISCHES MUSEUM, BASEL, SWITZERLAND INTRODUCTION Aequipecten ( Plagioctenium) spectes A report on Miocene and Pliocene mol Anon~ia simplex d'Orbigny lusks from Trinidad ( Jung, 1969) was Crassmella species completed when the writer undertook the Trachycardium (Dallocardia) scmctidavi identification of a small molluscan fauna dis (Maury) fron1 the Talparo Formation of Trinidad. Semele purpu1ras cens ( Gmelin) This faunule had been collected by Karl Strigilla ( Pisostrigilla) pisijo1rmis Rohr ( KR 13900 ) in the Mahaica (Linne) District, which is situated on the north Donax d. D. striatozts Linne ern slope of the Central R ange of Trinidad, ]uliacorbula aequivalvis (Philippi) about 14 kilometers south of Arima. The Gastropoda: fossiliferous outcrop had been found in Diodo1ra cayenensis (Lamarck) a branch stream of the Cunupia River N eritina species (coordinates: N 360' 060 links, E 445' Turritella (Broderiptella) aff. T. plani- 260 links ) . The exact geographic location gyrata Guppy of this outcrop is shown on a detailed C erithiopsis species map to be published by H . G. Kugler, Basel. Modulus species According to Kugler ( 1961, map) this lo Triphora species cality ( = Naturhistorisches Museum Basel Natica (Naticarius) aff. N. canrena locality 1043 7), which is situated on the (Linne) axis of the Mahaica anticline, belongs to the Crucibul-ztm ( C1rucibulum) piliferum Caparo Clay Member of the Talparo Forma Guppy tion and has been selected as the type lo Olivella (Niteoliva) d. 0. verreauxii cality for n1ollusks of the Caparo Clay Mem (Ducros) ber (Kugler MS ) . Prunttm ( Prmzum) aff. P. dallianum According to Rohr (private report, 193 7) (Maury) the faunule came from a 15 feet thick lens of limonitic or glauconitic conglomeratic Of these 22 forms there are 12 species sandstone situated in the uppermost part occurring in the Manua shell bed as well. of the Caparo Clay Member. The lithologi The remaining 10 forms belong to genera cal and faunistical aspects of the faunule represented also at Manua. But unfortu are strikingly similar to those of the fauna nately they are not determinable specifically, from the Matura shell bed. Their correla although it is probable that they are con tion, therefore, seems highly probable. specific with those found at Manua. Ba1' batia ( Obliquarca) d. B. cancellcwia (La FAUNA marck) and Prunum ( Pr-zmum) aff. P. All the specimens contained in this dallianttm (Maury) are the only species not faunule are strongly rolled, a feature ob recorded from Manua. In addition the form served frequently in material from the listed above as Modulus species is repre Matura shell bed as well. A number of sented by a single, fragmentary, worn speci forms cannot be identified specifically, be men, and is not conspecific with M. car cause they are represented by small frag chedonitts (Lamarck) recorded from the ments only. The following 22 forms have Manua shell bed (Jung, 1969, p. 452). been recognized from NHMB locality 104 3 7 : Genus BARBATIA Gray Pelecypod a: Gray, 1842, Synopsis of the contents of the British Museum, eel. 44, p. 81. Barbatia ( 0 bliquctfCa) d. B. cancellaria (Lamarck) Type species (by subsequent designation, N oetia ( Eontia) cent1ro ta (Guppy) Gray, 1847, Proc. Zool. Soc. London, pt. Brachydontes species 15, p. 197), Area barbata Linne. Recent, 0 strea species Mediterranean Sea. 85 86 T11lane St11dies Ill Geolog)' and Paleontology Vol. 7 Subgenus OBLIQUARCA Sacco Genus NOETIA Gray Sacco, 1~9~, I .Molluschi dci terreni terziarii Gray, 1857, Ann. Mag. Nat. Hist., ( ser. 2) vol. del Piemonte e della Liguria, pt. 26, p. 16. 19, p. 371. Type species (by original designation), Type species ( by monotypy), N oetict tri Area modiolifonnis Deshayes. Eocene, aJzgularis Gray ( = Area 11everset G. B. Paris Basin. Sower by I ) . Recent, eastern Pacific. BARBATIA (0BLIQUARCA) d. Subgenus EONTIA MacNeil B. CANCELLARIA (Lamarck) \facNeil, 1938, U. S. Geol. Survey, Prof. Paper Plate 1, figs. 1,2 189-A, p. 11. This species is represented by a few in Type species ( by original designation) , Aua complete and strongly worn shells. The lack ponderosa Say. Recent, east coast of the of reduced denticles at the center of the United States. hinge may be due to erosion. The ligament NOETIA (EONTIA) CENTROTA (Guppy) is narrow and restricted to the area behind the beaks. The external sculpture is hardly Plate 1, figs. 3,4 recognizable, but consists of numerous ra 1867 Area centrota Guppy, Proc. Sci. Assoc. dials. Trinidad, pt. 3, p. 175. (Reprint, Harris, 1921, Bulls. Amer. P:;]eontology, vol. 8, no. 35, p. 54.) B. cancellaria sometimes occurs abundantly 1938 Eontia cent rota (Guppy), MacNeil, U. S. in the Recent Caribbean fauna (Abbott, Ceol. Survey, Prof. Paper 189-A, p. 12, pJ. 1. 1958, p. 110). It is usually assigned to the figs. 11,12. Lectotype figured. For adcbtional subgenus Barbatia. Sacco originally included citations see this publication. 1942 Eontia centrota (Cuppy), Rutscb, Verh. only modioliform species in his subgenus Naturf. Ges. Basel, vol. 54, p. 110. Obliquctrca, but Woodring ( 1925, pp. 38- Lectotupe: USNM 496508. 40) described three species from the Bow Tupe lo calitu: Matura, 'Trinidad. den Formation of Jamaica, two of which Although most abundant at its type lo are not modioliform at all. According to cality, this species is represented only by a Reinhart (1935, p. 25) Obliqztarca is dis few valves in the faunule under study. They tinguished from Barbatia s. str. by having do not reach the size of valves from the its ligament entirely behind the umbones. Matura shell bed. As stated by Olsson ( 1961, p. 81) "the N. cent11ota has not been found outside ligament covers only the posterior part of Trinidad yet. It has been collected from de the cardinal area" in B. cancellaria. posits of late Miocene to Pliocene age. EXPLANATION OF PLATE 1 Figure Page All the specimens are from Naturhistorisches Museum Basel locality 1043 7. 1,2 Barbatia ( Obliqttm'ca) d. B. cancellaria (Lamarck) (X 2) ______ 86 Length 22.3 mm; height 12 .8 mm. Nat. hist. Mus. Basel No. G 14061. 3,4 N oetia ( Eontia) centrota (Guppy) (X 2) _ __ _ ____ __ __________________ 86 Length 22.2 mm; height 14.3 mm. Nat. hist. Mus. Basel No. G 14062. 5 ]ztliacorbula aeqztivctlvis (Philippi) (X 5) __ __ 88 Length 6.7 mm; height 5.1 n1m. Nat. hist. Mus. Basel No. G 14063. 6 C11ucibztlttm ( Crucibztlum) pilifentm Guppy (X 2) __ _ ___ 88 Maximum diameter 16.7 mm. Nat. hist. Mus. Basel No. H. 15402. 7 Tunitella ( B1roderiptellct) aff. T. planig)wata G uppy (X 2) _ 88 Height 32.0 mm; maximum diameter 14.2 mm. Nat. hist. Mus. Basel No. H . 15401. 8 Pnmum ( P11unum) aff. P. dallianzmz (Maury) (X 2) _ _ _ 88 Height 21.2 mm; width 17.2 mm. Nat. hist. Mus. Basel No. H. 15403. No. 2 Pliocene Molluscan Faunule) Trinidad 87 2 5 6 PLATE 1 T ulane Studies in Geolog;· and Paleontology Vol. 7 Genus JULIACORBULA Olsson and Harbison Genus CRUCIBULUM Schumacher Olsson and Harhison, 195.3, Acad. Nat. Sci. Schumacher, 1817, Essai d'un nouveau systeme Philadelphia, .\tonograph no. 8, p. 148. des habitations des vers testaccs, pp. 56,182. Type species ( by subsequent designation, Type species (by original designation), Burch, 1946, Min. Conchological Club Corbula cubaniana d'Orbigny ( = Cor Southern California, No. 56, p. 19), bttla knoxiana C. B. Adams = Corbttla Crucibztlum planum Schumacher ( = Pa aequi-vafvis Philippi ). Recent, Florida tella auricula Gmelin) . Recent, Florida and Caribbean. and West Indies. JULIACORBULA AEQU IVALVIS ( Philippi) Subgenus CR UC IBULUM s. str. Plate 1, fig. 5 CRUCIBULUM ( CRUC IB ULUM) 18.36 Corlmla aect uivalv is Philippi, Archiv hir PILIFERUM Guppy P.'aturg., 'ol. 2, p. 227, pl. 7, fig. 4. Plate 1, fig. 6 1964 Corbula ( ]uliacorbula) aequivalvis Phi lippi, \Veishord, Bulls. Amer. Paleontology, 1867 C ru cib ulum piliferum Guppy, Proc. Sci. vol. 45, no. 204, p . .39.3, pl. 57, figs . .3- 6. For Assoc. Trinidad, pt. 3, pp. 160,172. ( Reprint, further citation see this publication. Harris, 1921 , Bulls. Amer. Paleontology, vol. 8, no. 35, pp. 39,51. ) ]. aequivalt1is occurs abundantly in the This species is represented by five speci Matura shell bed, but is represented in the mens. Their spines are but poorly developed, faunule under study by a few valves only. or even absent on account of erosion. Un At Matura the specimens vary in shape from usually fl at shells such as occur at Matura subquadrate to elongate. The same variability are m1ss mg. is shown by the Mahaica valves. R elated forms are discussed elsewhere ( Jung, 1969, Genus PRUNUM Herrmannsen p. 410). Herrmannsen, 1852, Indicis generum malaco zoorum. Supplementa et corrigenda, p. 113. Genus T URRITELLA Lamarck Type species ( by monotypy ) , V oluta prunum Lamarck 1799, Mcm. Soc. Hist. Nat. Paris, p. Gmelin. Recent, West Indies. 74. Subgenus PRUNUM s. str. Type species ( by monotypy), Turbo terebra PRUNUM ( PRUNUM) aff. Linne. Recent, western Pacific. P. DALLIANUM (Maury ) Subgenus BRODERIPTELLA Olsson Plate 1, fig. 8 Olsson, 1964, Neogene mollusks from north A single shell is available. It is damaged western Ecuador, p. 188. Paleont. Research and somewhat worn, but its outer lip is Inst., Ithaca, N. Y. preserved. P. dallianum (Maury) ( 1912, Type species ( by original designation) , T ur p. 67, pl. 10, figs. 5, 6 ) was originally de ritella broderipiana d'Orbigny. Recent, scribed from the Courbaril beds (Pliocene) eastern Pacific. of the Pitch Lake area, Trinidad. Comparison with topotypes shows that the Mahaica TURRITELLA ( BRODERIPTELLA) aff. speci men is stouter. The upper part of its body T. PLANIGYRATA Guppy whorl is more inflated, the lower part n1ore Plate 1, fig. 7 constricted, and its outer lip is more strongly arched.