THE TRUNCARIA (:) IN THE ESMERALDAS BEDS OF NORTHWESTERN ECUADOR

EMILY H. VOKES TULANE UNIVERSITY

In collections made in the Early Pliocene The problem of mislocated Adams and Esmeraldas fauna, Onzole Formation, of Reeve species was discussed in an earlier northwestern Ecuador, there are four ex­ work by Pilsbry and Olsson (1935, p. 121), amples of a species of the genus Truncaria wherein the bivalve species Mactra Adams and Reeve, 1850, which previously thmcoides Adams and Reeve, 1850, also has been known only from the Recent described in the Voyage of the Scnnamng fauna. Wenz (1941, p. 1194) included in the (1850, p. 81, pl. 23, fig. 8) from the "Eastern synonymy of Truncaria, the Eocene genus Seas," was demonstrated to be a native of Coptaxis Cossmann (1901, p. 226; proposed the coast of Peru. The a uthors suggest that as a replacement name for Buccinopsis Sir Edward Belcher, who was captain of Deshayes, 1865, non Conrad, 1857) and the Samarang during the voyage in 1843- cited the genus as occurring in the Eocene 46, had acquired the material on his previ­ of Eur ope with one species in the Recent. ous voyage, that of H. M.S. Sulphur, which T here is no more than a familial similarity surveyed the coast of western America between these two totally disjunct occur­ from Peru to Sitka during the years 1836- rences and Truncaria has not been recog­ 1842, just prior to the voyage of the nized previously as a fossil. Samarang. They note that Captain Belcher Initially I thought that these specimens was a shell collector himself and often held were referable to the Esmeraldas species out some of the best specimens for himself. Olsson named nephale (1964, p. In the same paper in which he placed T 161, pl. 38, fig. 6), but examination of the brunneocincta in the synonymy of T. holotype of that species (USNM 644040) filosa, Olsson (1971, p. 62) noted that there shows it to be a larger, more strongly or­ were fragments of a Caribbean shell namented shell, lacking the truncated col­ "suggestive of Truncaria" in the collections umella of Truncaria. It is not as strongly of the Rosensteil School of Marine and At­ cancellate as most species of Metula and mospheric Sciences, University of Miam1. may prove to be referable to Bartschia These were subsequently named Trun· Rehder, 1943, when better material is caria lindae by Petuch (1987, p. 103, pl. 21, available. In any case, it is not the same as figs. 16-18), who explained: "I felt it was the species described here. important that this new species be de­ T he genus TTuncaTia, w hich Olsson scribed, even from fragments !two frag­ (1971, p. 62) described as "a curious genus ments, one 16 mm, the other 13 mm in and readily recogizable by the shape of the length], in order to establish a Caribbean shell, its smoothish, spirally lined sculp­ member of the genus and to remove Trun ture, and especially by the oblique trunca­ caTia from the list of paciphilic genera.'' tion of its columellar end" was named by However, I am not aware of any fossil Adams and Reeve (1850, p. 33) for the species of Truncaria in the Caribbean species filosum Adams and fauna, a necessary condition to have a true Reeve, 1850, originally described as being "paciphile." from the "China Sea." However, Olsson, The Esmeraldas specimens, although after examining the holotype of B. filosum similar to the living Panamanian T. filosa, (Plate l, fig. I) in the collections of the arc sufficiently distinct to merit naming. As British Museum (Natural History) con­ noted previously, in a study of the muricid cluded (1971 , p. 63) that the locality "China fauna of the Esmeraldas Beds (Vokes, Sea" is incorrect and the species is, in fact, 1988, p. 9), the molluscan fauna of these the Panamanian one subseque ntly named Early Pliocene beds has its greatest affinity brunneocincta (Plate I , fi g. 2) by with the Recent fauna of the eastern Dall (1896, p. I I ; fi gured as Truncaria Pacific. But, also as noted, many of the brunneocincta, Da ll , 1908, p. 304, pl. 2, fi g. species present in the Esrneraldas are not 6; holotype figured in color by Abbott and found so far south today. The living spec1es Dance, 1982, p. 170). has been reported only from the Bay of 97 98 Tulane Studies in Geology and Paleontology Vol. 24

Panama (Keen, 1971, p. 572, as T. brun­ east edge of village of Camarones, 20 km (by neocincta, fig. 1151 [after Dall, 1908, pl. 2, road) east of the bridge over Rfo Esmeraldas, at fig. 21; name changed to T. jilosa, p. 854; Esmeraldas, or approximately 10 km east of the and Olsson, 1971, p. 63). mouth of Rio Esme1·aldas, Pmv. of Esmeraldas, Ecuador.

Ti{UNCARIA PITT! E. H. Vokes, n. sp. Discussion: In the four specimens com­ Plate 1, figure 3 prising the type lot of this new species, not one has the early whorls well preserved. Description: Shell elongate, protoconch prob­ ably of one !urge smooth , usually broken However, one example does have the pro­ and plugged by (three of four· speci me ns toconch remaining and it appears to be in type lot); approximately seven teleoconch identical to the living T . .filosa. The or­ whorls in adult. Ornamentation on early tele­ namentation on the early teleoconch oconch whorls fOrmed by intersection of spiral whorls is cancellate, becoming smoother and axial grooves, both on the order of 5/mm, with each successive whorl. The differ­ giving rise to small raised squares; these losing ences between T. pitti and T. filosa are prominence as shell grows, causing a linen-like minimal; the most conspicuous is the color texture in adult. On spire whorls about 12 to 15 spiral g rooves, on body whorl between 40 and 50 pattern, which is well preserved in all the grooves, of varying strength, only approxi­ fossil specimens and must have been much mately alternating between weaker and more brilliant than in the Recent species. stronger. Axial gr·ooves decreasing in strength In T. filosa there are fewe r spiral grooves as s hell si:le in cre<.~ses, somewhat "puckered" (about 20 to 25 on body whorl) a nd the nar­ toward suture, spreading out over periphery of row color bands follow every other spiral s hell. Suture deeply incised, set mor·e anteriorly groove. In the fossil species the color on each successive whorl, causing increased bands cover the area between two spiral elongation as shell enlarges. teardrop­ grooves and are separated by three spiral shaped, narrower posteriorly, wider anteriorly. Inner lip smooth, appressed; at anterior end a grooves. The Recent species a lso has a single columellar plication, almost parallel to series of colored fla rnules on the sub­ axis of shell. Outer lip slightly thickened, faint sutural area and a very faint wider colored denticles on inner side, that at posterior end the band around the periphery; the fossil strongest. truncated, turned shells give no evidence of having had such parallel to the apertural opening, in the direc­ markings. Although both species begin life tion opposing the outer lip. Color pattern of red­ with a cancellate surface ornamentation, dish-brown spiral bands, approximately 15 on the Recent T . .filosa soon loses most of the body whorl, separ·ated by wider non-colored axial g rooves, leaving the body whorl bands. Holotype: USNM 153854; he ight 32.1 mm, di­ much smoother and more polished in ap­ ameter 1:~ . 6 mm. pearance than the linen-like T. pitti. Type locality: TU 1397, Esmer<.~ldas Beds, The type specimen of Truncaria brun­ Upper On:lole Formation; Quebrada Camaro­ neocincta was taken at a depth of 102 met­ nes, cut-bank on east s ide of canyon, which is at e rs, and Olsson's materia l was from 77-79

PLATE! Figures J. Truncaria.filosa (Adams and Reeve, 1850) BMNH 1878.1.28.13 (holotype); height 28.6 mm, diameter 11.5 mm. Locality: "China Sea." 2. Truncaria.filosa (Adams a nd Reeve, 1850) USNM 123009 (holotype-Cominella brunneocincta Dall, 1896); height 31.5 mm, diam­ eter 13.6 mm. Locality: U.S. Fish Comm. Station 3390, Gulf of Panama, 56 fms (102m). 3. Truncaria pitti Vokes, n. sp. USNM 453854 (holotype); height 32.1 mm, diameter 13.6 mm. Locality: TU 1387, Esmeraldas Beds, Ecua dor. (All illustrations X 1 1/2 except 2e, f, and 3d, e, X 3; figures 2c-e, and 3a, b, d, whitened to show details of ornamentation) No.4 Truncaria in Northwestern Ecuador 99

3b

2e

3d 3e

3C

PLATE 1 100 Tulane Studies in Geology and Paleontology Vol. 24 meters, a ll from the Bay of Panama. Our COSSMANN, M., 1901, Essais de Paleocon­ Esmeraldas specimens came from locality cho logie comparee, v. 4, p . 1-293, pis. 1-10. TU 1397, Quebrada Camarones, and so the DALL, W. H. , 1986, Diagnoses of new species of living depth of the Recent species corrobo­ mollusks from the west coast of America: U. S. Nat!. Mus., Proc., v. 18, no. 1034, p. 7-20. rates an earlier statement (Vokes, 1988, p . DALL, W. H., 1908, Reports on the dredging op­ 8), wherein it was noted that the gravity erations ofT the west coast of Centr·al Ameri­ slide, which brought the Esmeraldas fauna ca to the Galapagos, to the west coast of into the deep-water (ca. 1000 meters) clays Mexico, and in the Gulf of California, in of the Onzolc Formation, began in shal­ charge of Alexander Agassiz, carried on by lower water, on the order of 75 meters. the U. S. Fish Commission steame r· "Alba­ The species is na med for my colleague tross,'' during 1891.. XXXVII. Reports on and co-worker on the Esmeraldas fauna, the scientific r·esults.. XIV. The William D. Pitt, of Sacramento, California, and the Brachiopoda: Harvard Mus. Comp. Zool., Bull., v. 4:3, no. 6, p. 205-487, pis. 1-22. who identified the species as being Trun­ KEEN, A. M., 1971, Sea shells of tropical west caria sp. at"f. brunneocincta (Dall). He also America, marine mollusks from Baja Califor­ provided the type specimen, the best of the nia to Per-u. Second Edition. Stanfor·d Uni­ four in our combined collection. versity Press, Stanfor·d, Californa, xiv I 1061 I wish to acknowledge my gratitude to p., 22 color plates, ca. 4000 figur·es, 6 maps. Kathie Way, British Museum (Natural His­ OLSSON, A. A. , 1964, Neogene mollusks fr·om lory), and M.G. Harasewych, United northwestern Ecuador. Paleontological Re­ Stales National Museum, who loaned the search Institution, Ithaca, New York, 256 p., type specimens of T. filosa and T. brun­ 38 pis. OLSSON, A. A., !971, Mollusks f•·om the Gulf of neocincta, figure d here. Thomas R. Wal­ Panama collected by R/V John Elliott ler, also of the United Stales National Pillbury, 1967: Bull. Marine Sci., v. 21, no. 1, Museum, loaned the type of Metula p. 35-92, figs. 1-103. nephale Olsson, for comparative purposes. PETUCH, E. J., 1987, New Caribbean mollus­ Thanks go to all of them. can faunas. Coastal Educ. & Resh. Found. (CERF), Charlottesville, Virginia, 154 1- 4 p., LITERATURE CITED 29 pis., I text-fig. P!LSBRY, H. A., and A. A. OLSSON, 1935, ABBOTT, R. T., and S. P. DANCF., 1982, Com­ New mollusks from the Panamic Province: pendium of seashells, a color guide to mo,·e Nautilus, v. 48, no. 3, p. 116-121 , pl. 6. than 4,200 of the world's marine shells. P. E. REHDER, H. A., 1943, New marine mollusks Dutton, Inc., New York, 411 p., 4,200 I un­ from the Antillean reg ion: U.S. NaU. Mus., numbered colored illustrations. Proc., v. 9:l, no. 3161, p. 187-203, pis. 19, 20. ADAMS, A., and L.A. REEVE, 1848-1850, Mol­ VOKES, E. TT ., 1988, Muricidae (Mollusca:Gas ~ lusca, in The zoology of the voyage of tmpoda) of the Esmeraldas beds, nor·thwest­ H.M.S. Samarang, under the command of ern Ecuador: Tulane Stud. Geol. P a leont., v. Captain Sir· Edward Belcher . 1843-1816 21, no. 1, p. 1-50, pis. 1-6, 15text-figs., I table. (A. Adams, ed.) Reeve, Benham, <:md WENZ, W. , lB41 , Handbuch der Paltiozoologie, Reeve, London, x 1 87 p., pis. 1-24 [p. 1-24, v. 6, pt. 1 - Gastropoda, lief. S, p . 959-1200, pis. 1-9, Nov. 1848; p. 25-44, pis. 10-17, May r.gs. 2788-3416. 1850; p. 45-87, pis. 18-24, Aug. 18501. October 9, 1991