TULANE STUDIES IN GEOLOGY AND PALEONTOLOGY Volume 22, Number 4 December 28, 1989

MURICIDAE (MOLLUSCA:GASTROPODA) OF THE ANGOSTURA FORMATION NORTHWESTERN ECUADOR '

EMILY H. VOKES TULANE UNIVERSITY

CONTENTS I. ABSTRACT page II. INTRODUCTION . . . . 107 107 III. ACKNOWLEDGMENTS . 112 IV. SYSTEMATIC PALEONTOLOGY : : : : : 112 V. LOCALITY DATA 117 VI. LITERATURE CITED 117

I. ABSTRACT The muricid fauna of the Late Miocene Angostura Formation, northwestern Ecua­ dor, includes two species previously known from the Gatun Formation of Panama, the Esmeraldas Beds of Ecuador, and other localities in the Caribbean Ter­ tiary. There are also two new species de­ scribed herein. One, Eupleura olssoni, is most closely related to an unnamed Gatun species; the second, Ceratostoma (Micro­ rhytis) ecuadorium, is most closely related to C. (M.) pecki (Emerson), described from the Atlantic side of the Isthmus of Tehuan­ tepec, Mexico. Thus, the muricid fauna has a closer affinity with the Tertiary beds of the western Atlantic than with the Re­ cent fauna of the eastern Pacific .

II. INTRODUCTION Text-figure 1. Map of northwestern Olsson (1964, p. 8) noted that the Mio­ Ecuador, showing study area. cene section along the Rfo Santiago, in northwestern Ecuador, begins w ith the tura beds are largely barren, in places Angostura Formation, stating: "The lowest there are lenses of finely preserved fossils, part of the Miocene sequence is formed by the principal localities in the area being the the Angostura formation, named from the so-called "Cueva de Angostura," on the Angostura gorge, and consists predomin­ Rio Santiago, and Telembi, an Indian vil­ antly of coarse sandstones a nd beds of con­ lage on the Rio Cayapas, which parallels glomerates, about 150 meters in thick­ the Rio Santiago to the west An attempt ness." He added that, although the Angos- by the author to re-collect these two

EDITORIAL COMMITTEE F OR THIS PAPER: C. ROGER BRISTOW, British Geological Survey, Exeter, England WILLIAM K. EMERSON, American Museum of Natural History, New York, New York JOHN E. WHITTAKER, British Museum (Natural History), London, England 107 108 Tulane Studies in Geology and Paleontology Vol. 22

RKO VJERDJE

Text-figure 2. Map of Rio Verde area, Province ofEsmeraldas, Ecuador. localities was fo il ed by the caprices of na­ taker , 1988, p. 11), the assumption is that tu re - water too low on the Rio Santi ago , the Angostura Formation is probably Late and, at the same ti me, too high on the Rio Miocene in age. If this is the case, then the Cayapas. unit may be slightly older than the Gatun Fortunately, there is another excellent Formation of Panama, with which it was section of the Angostura Formation ex­ correlated by Olsson (1964, p. 8). This is re­ posed along the coast east of Rio Verde, a flected in the molluscan fauna, which, as fishing village at the mouth of the Rio Olsson note d , is close ly relate d to the Verde, about 30 km east of the city of Es­ Gatun and "many Angostura species de­ meraldas (see text-fi gs. I , 2). T here a mag­ scribed as ne w differ from related Gatun nificent section is exposed (text-figs. 3, 4), species only in small particulars." which, according to Whittaker (1988, p. The reason why the Angostura fauna 101, consists of the Middle Miocene Viche has such a strong resemblance to that of Formation (planctic foraminiferal zone N the Gatun is more a matter of facies than 12) at the base and the Late Mi ocene time. The two formations are identical in Lower Onzole Formation (N 16) at the top, facies, both being shallow-water, near­ with the Angostura Formation in between shore units. Many of the species, at first (text-fi g. 5). Whittaker descr ibes the An­ glance, seem to be the same as those in the gostura Formation at this locati on as rest­ Gatun but, upon close r examination, prove ing "with a sharp conformable contact on to be, as Olsson noted , sli ghtly different, the Viche mudstones," but the contact is which should make evolutionary gradua­ markedly eroded (te xt-figs. 6, 7) a nd is bet­ li sts ve ry happy. Of the four muricid ter classifie d as disconformable. species treated he rein, Olsson had two The age of the Angostura Formation is from the Angostura beds at Cueva de An­ uncertain , as the re are no diagnostic gostura a nd Te lembi: Haustellum planktic fo ra minifera in these shallow­ polynematicus (Brown and Pilsbry), which water beds. However, as the beds of the also occurs in the Gatun Formation, the Lower Onzole Formation, resting im­ Esme raldas beds, and unnamed beds in mediately above the Angostura at P unta southe rn Colombia (see Vokes, 1988, p. Verde, are dated as latest Miocene (Whit- 17); and Eu pleura olssoni, n. sp. , which is No. 4 Muricidae of Angostura Formation, Ecuador 109

Text-figure 3. Sea cliffs, exposed along coast at Punta Verde, Province ofEsmeraldas, Ecuador.

Text-figure 4. Section exposed in sea cliffs at Punt~ Verde. Darker beds at bottom of picture are Angostura Formation; li ghter beds at top are Lower Onzole Formatioll. 110 Tulane Studies in Geology and Paleontology Vol. 22

that, as one walks along the beach east­ ward from the town, the northwesterly dip of the beds gradually exposes the complete section. Initially, the cliffs are composed of an unfossiliferous gray silt, which Whit­ taker re fers to the Lowe r Onzole Forma­ tion. The first (stratigraphically highest) fossiliferous beds consist of a indurated, massive sandstone, containing numerous pe ctens, sand-dollars, and many speci­ me ns of Ostrea haitensis Sowerby, 1850, a common fossil throughout the Caribbean. This is underlain by a sandy lens fill ed with LOWER ONZOLE FM ra ther chalky pelecypods and gastropods llAH MIOCENE ! of many species. Beneath this is a non-fos­ ANGOSTURA FM !LAIEMIOCEm) siliferous zone and, finally, at the base of El the Angostura Formation, where it rests YICHE FM on the Viche, there is another lens of mol­ ~ (fAMl Y•MIODl EMIOCENE ) luscan fossils. This latte r zone is crowded PAMBIL FM with specimens of Turritella, but it is also llilll (l AIE OllOOC fNE ) in this level that the muricid specimens occur. The first time we visited Punta Verde the re was a small area with well­ preserved fossil mollusks in the w ave-cut be nch exposed al low tide . However, Text-fi gure 5. Geologic map of Rio when we returned in 1988, sand had com­ Verde area (from Wh ittaker , 1988, fi gure 2; plete ly covered this outcrop a nd w e could numbers are his collecting sites). Our local­ find no trace of it. ity is approximate ly the same as JW 288. Beneath the Angostura Formation lies the Viche Formation, which has no fossil mollusks in it. The conta ct is highly irregu­ related to another Gatun species (not E. lar, with many burrows extending from the thompsoni Wo odring, as in dicated by Angostura down into the indurated clay of Olsson). H e also listed Typhis alatus Sow­ the Viche beds. The majority of the best­ erby from the Picade ros [ ~ Onzole) For­ pre se rve d fossils lie just above this contact. mation, w hich overlies the Angostura on The Angostura Formation presumably the R io Santiago. This long-ranging latter represents a lrangression over the semi­ species occurs throughout the Caribbean lithified beds of the Viche Formation. The from the Middle Miocene of the Dominican contact with the overlying Onzole Forma­ Republic to the Early Pliocene Gatun For­ tion is gradational and probably represents mation. The only other muricid species, the natura l deepening of the basin. describe d herein as Ceratostoma (Mi cro­ rhytis) ecuadorium, is most closely related The Angostura muricid fauna is rich to C. (M .) pecki (Emerson ), described from ne ither in numbers of species nor in indi­ Middle Miocene (N 13- 14) bed s in the Is­ viduals . However, as the oldest fauna in thmus of Tehuantepec, Me xico. the transgressive sequence that culminates The locality at Punta Verde was origi­ in the rich muricid fauna of the Esmeraldas nally discovered by Roger Bristow and Be ds, it is of interest to see the make-up of J ohn Whittaker , of the Briti sh Geological the shallow-wate r facie s. In the same area Su rvey and the British Museum (Natural today the re are living the descendants of History), De pa rtment of Palaeontology, re­ just one of these species , Eu pleura olssoni, spectively. They told William a nd Lois Pitt n. sp. No longer is there any species that about the locali ty and, togethe r with Mr. can be related to Haustellum polynemati­ and Mrs. Pitt, my husband a nd I first vis­ cus, Typhis alatus, or Ceratostoma (Micro­ ited P unta Verd e in 1986. There we found rhytis) ecuadorium, n. sp. No. 4 Muricidae of Angostura Formation, Ecuador Ill

Text-figure 6. Contact of Angostura Formation on older Viche Formation, Punta Verde, Ecuador.

Text-figure 7. Closeup of Viche-Angostura contact, showing irregular contact (most of the gastropods in this photograph are living specimens of Littorina, but one can see peb­ bles and shells near the basal contact of the Angostura Formation). 112 Tulane Studies in Geology and Paleontology Vol. 22

III. ACKNOWLEDGMENTS gilli (Maury)]. Murex (Haustellum) polynematicus Brown and The greatest thanks are extended to Pilsbry. VOKES, 1988, Tulane Stud. Geo!. both C. Roger Bristow, British Geological Paleont., v. 21, no. 1, p.17, pl. l, fig. 6. Survey, and John E. Whittaker, British Holotype: ANSP 1719; height 54.5 mm, diame­ Museum (Natural History), Department of ter 33. 7 mm. Palaeontology, for all the information that Type locality: Gatun Formation; Gatun Locks, they have made available (both published Panama. and non-published) concerning the geol­ Occurrence: Angostura Formation and Es­ ogy of the coast of Ecuador. For the loan of meraldas Beds, Ecuador. Gatun Formation specimens I am grateful to George M. Panama; unnamed formation, Narlno, Colom~ Davis and Elena Benamy, Academy of bia; Pliocene. Natural Sciences, Philadelphia, and Figured specimens: Fig. 1, USNM 445397; Thomas R. Waller and Warren Blow, U.S. height 41.5 mm, diameter 27.4 mm; locality TU National Museum. William and Lois Pitt, of 1507. Fig. 2, USNM 445398; height 43.0 mm, di­ a meter 25.5 mm; locality TU 1433. Sacramento, California, have been tireless collectors and cheerful traveling compan­ Discussion: The generic placement of ions, offering all manner of help and moral the species originally named Murex support in our on-going Ecuadorian pale­ polynematicus and its close relative, origi­ ontological studies. nally named Fusus gilli Maury, 1910, has long been a problem to the writer. In a re­ IV. SYSTEMATIC PALEONTOLOGY cent work (Ponder and Vokes, 1988) on the genus Mure.r s.s. in the Indo-Pacific, it was Class GASTROPODA determined that the muricine species in Order NEOGASTROPODA the New World, which have been custom­ Superfamily MURICACEA arily assigned to Murex s.s., are better Family MURICIDAE Rafinesque, 1815 placed in the genus Haustellum. This Subfamily MURICINAE Rafinesque, 1815 causes problems for a few of the more Genus HAUSTELLUM Schumacher, 1817 spinose forms, but it is obvious that Haus­ Haustellum SCHUMACHER, 1817, Essai Nouv. tellum is the correct genus for both H. Syst. Vers Test., p . 213 . polynematicus and its ancestor H. gilli. Type species: Murex haustellum Linn., 1758, There should be no more changes for by tautonomy. these two species, at least. Haustellum polynematicus has been dis­ HAUSTELLUM POI.YNEMATICUS cussed in detail in a previous study on the (Brown and Pilsbry) Esmeraldas Beds (Vokes, 1988, p. 17) and Plate 1, figs. I, 2 little can be added at this point. The Murex (Murex) polynematicus BROWN a nd species, so far as we know, has no living PILSBRY, 1911, Acad. Nat. Sci. Phila., d escendants, although it was the most Proc., v. 63, p. 353, pl. 26, f"lg . l; OLSSON, abundant and widespread muricid in the 1964, Neogene Mo!!. Northwest. Ecuador, p. shallow-water of the Pliocene Panamic 137, pl. 29, figs. 2, 2a. Province. Curiollsly, it never extended its Murex (Murex?) polynematicus Brown and Pilsbry. WOODRING, 1959, U. S. Geo!. range into the more northern Dominican Surv., Prof. Paper 306-B, p. 215, pl. 36, figs. Republic, where H. messorius (Sowerby, 2, 3; pl. 37, figs. 6-9. 1841) occupies the same ecologic niche, nor Murex (Murex) gilli polynematicus Brown and is it found in the Rio Banano Formation of Pilsbry. VOKES, 1963, Tulane Stud. Geo!., Costa Rica, which is only about 300 km v. 1, no. 3, p . 101, pl. 2, fig. 5. from the contemporary occurrence in the Murex messorius Sowerby. VOKES, 1963, Gatun Formation in Panama. In the Rio Tulane Stud. Geol., v. 1, no. 3, pl. 3, fig. 8 Banano, H. messorius is also the Haustel­ only (not of Sowerby). Chicoreus (Siratus) gilli polynematicus (Brown lum species that occurs. Obviously, H. and Pilsbry). VOKES, 1965, Tulane Stud. messorius was a better competitor, as is Geo!., v. 3, no. 4, p. 183. borne out by the fact that H. messorius is Not Murex (Murex) polynematicus Brown and still living today throughout the Caribbean Pilsbry. JUNG, 1965 , Bu!ls. Amer. Paleontol­ and no trace of H. polynematicus is to be ogy, v. 49, no. 223, p. 520, pl. 69, fig. 6 f H. seen. No. 4 Muricidae of Angostura Formation, Ecuador 113

Subfamily THAIDINAE Jousseaume, 1888 Middle Miocene (N 13- 14) (TU 635. "En­ Genus CERATOSTOMA canto Formation" of Akers). Until we have Herrmannsen, 1846 more material, placement of this taxon re­ Cerostoma CONRAD, 1837, Aca d. Nat. Sci. mains questionable. Phila., Jour., v. 7, p. 263. Type species: Murex (Cerostoma) nuttalli CERATOSTOMA (MICRORHYTIS) ECUADORIU'.\1 Conrad, 1837, by monotypy. Vokes, n . sp. Ceratostoma HERRMANNSEN, 1846, lndic1> Plate 1, figs. 3, 4 Generum Malakoz. , v. 1, p. 206. New name for Cerostoma Conrad , 1837. non Latreille, Description. Shell of average size, probably 1802. six teleoconch whorls in adult; protoconch un­ known. Spiral ornamentation on early tele­ S ubgenus MICRORHYTIS Eme rson, 1959 oconch whorls of two strong cords, which persist up to the body whorl, where they form one Microrhytis EMERSON, 1959, Amer. Mus. weaker cord at the shoulder and another some­ Novitates, no. 1974, p. 6. what stronger cord just anterior to it. These sup­ Type species: Pterorytis (Microrhytis) pecki plemented by a third cord near base of the body Emerson, 1959, by original designation. whorl and numerous weaker threads between, Discussion: In a study of the genera of and anterior to, the three major cords. Axial or­ the Muricidae (Vokes, 1964, p. 23) I placed namentation on earliest whorls of approximately 12 small lamellar varices, crenulated by spiral the subgenus Microrhytis in synonymy cords; gradually reducing in number until on ap­ with the genus Ceratostoma . as both taxa proximately the fifth teleoconch whorl becoming are characterized by triva ricate shells that three varices with one strong intervarical node have a denticulate aperture and a strong between each pair. Varices fimbriated on labral tooth. However, the ea rly whorls of adapertural face, slightly recurved abapertur­ Ceratostoma s.s. bear no varices but are ally, with a weak fold at shoulder. In addition to simply cancellate until a pproximately the varices, the shell surface shagreened by numer­ fifth teleoconch whorl, at which point three ous axial growth lines. At juncture of body whor varices develop. In con trast. in Micro­ and s1phonal canal a sharp adaperturally di reeled labral tooth, causing the varix to be l·n rhytis (as in the genus Pterorytis Conrad, folded behind it. Aperture large, ovate; columel 1863, to which it is a lso closely related) on Jar lip smooth, adnate posteriorly, free-standing the early teleoconch w horls there are anteriorly. Inner side of outer lip with approxi numerous small lamellar va rices, which on mately seven strong elongate denticles. approximately the fifth te leoconch whorl Siphonal canal moderately long, wide, sealed reduce their number to three. over by an extension of shell material from col­ The question arises as to w hether Micro­ umellar side; distal end slightly recurved rhytis is more closely a llied w ith Cerato­ Paratype still showing color pattern of white spi· ral stripes overlying the major spiral cords on a stoma or with Pterorytis. To me, the large solid brown background. open aperture with stron g denticulations Holotype: USNM 445399; height 23.2 mm. di­ on the inside of the outer li p indicates a ameter 15.5 mm (Plate 1, fig. 3). closer relationship with Ceratostoma, in Paratype: USNM 445400: height 26.8 mm, di­ contrast to the more circular, non-denticu­ ameter 16.9 mm (Plate 1, fig. 4J. late a perture of Pterorytis. In Pterorytis Type locality: TU 1507, Angostura Formation, there are no intervarica l nodes (even in Punta Verde, large point just east of Rio Verde. specimens with only four va rices) and the or about 30 km east of Rio Esmeraldas, Province labral tooth is much large r tha n that seen of Esmeraldas, Ecuador. Occurrence: Angostura Formation, Ecuador in Ceratostoma. In addition, species of Pterorytis retain the more numerous var­ Discussion There are just two spt.•c1- ices (the least number in a ny species is mens of this new species, one that is coP1- four) a nd these varices are more wing-like plete but immature, and a second tha1 b and expand ed tha n in Microrhytis. But. mature but lacks the apertural side. the case could be made for either place­ Nevertheless, the form is so distincti\'e ment with equal validity . The only species there is no question of its relationship witb heretofore known of Microrhytis is the the Middle Miocene Ceratostoma 1 Micro­ type, described from an unna med forma­ rhytis) pecki !Emerson!, type of the sub­ tion in southern Mexico, in beds that have genus. The Mexican species, describl'd been d ated by Akers (1972, p. 11 ) as late from th~ Gulf Coastal Plain sidt> of the ls 114 Tulane Studies in Geology and Paleon tology Vol. 22 thmus of Tehuanlepec, d iffers from the tation on earliest teleoconch w horls of two sharp Ecuadorian one in lacking the relatively cords set very near anterior sutu re, leaving a strong spiral cords and the shoulder fold in wide, smooth , sloping shoulder ramp. On a bout the varices, but otherwise the two are re­ sixth teleoconch whorl a weake r cord interca­ lated onto shoulder ramp. On body whorl about markably similar. These two species are 12 cords, one at shoulder, one wea ker on the the only known representatives of the sub­ shoulder ramp, and approximately 10 weaker genus Microrhytis. ones anterior to shoulder, becoming progres­ The type locality of C. (M.) pecki (Uni­ sively less strong anteriorly, very faint on versity of California, Museum of Paleontol­ siphonal canal; between each pair of major ogy A-8125) is the same as our locality TU cords three lo five extremely faint threads. Axial 636, and is only 0.1 mile (0.16 km) from our ornamenta tion on earliest teleoconch whorls of locality TU 635 ( ~ UCMP A-2184, locality about 12 small lamellae, gradually reducing in of three paratypes), which, as noted number until on a pproximately the fi fth tele­ above, has been dated as Middle Miocene. oconch w horl only eight in number , with every fo urth one becoming an expanded varix; three The fauna at these two localities indicates nodes remaining between each pair of varices. extremely shallow water w ith numerous Varices aligned on opposite sides of the shell, specimens o f a Strombus sp. cf. S. pro­ with the varices of each successive whorl ximus Sowerby, 1850, described from the slightly in advance of varices on previous whorl, shallow-waler Cercado Formation of the leaving a visible offset with varices not fused to­ Dominican Republic. There is a large gether. Interva rical nodes persisting as rounded amount of fine gravel, and the assemblage, knobs, over which the spiral ornamentation is in general, looks as though it was almost diminished so that the knobs a ppear relatively intertidal. However, there is a good plank­ smooth. Varices extended as a series of webbed scallops between points formed by extensions of tic foraminiferal fauna, which would not be the spiral cords, that at the shoulder the longest found intertidally, and it is assumed that and adapically d irected; on varical faces spiral the mega-fossils were transported into the cords expressed as grooves into which the shell deep-water environment by a gravity-flow. laminae are enfolded. Aperture elongate-oval; inner lip appressed to columellar wall, with a few faint rugae reflecting underlying spiral EuPLEUHA OLSSON I Vokes, n. s p. cords. Margin of outer li p folded into the Plate 1, figs. 6, 7 grooves of the varical face, especially at the shoulder; six strong denticles developed on Eupleura thompsoni Woodring subspecies. inner side of outer lip, positioned between the OLSSON, 1964, Neogene Moll. Northwest. grooves. Siphonal canal mode rately Jong, Ecuador, p. 139, pl. 29, fig. 9. straight, almost closed but open by a na rrow slit. Description: S hell small, seven teleoconch Holotype: USNM 445402; height 26.3 mm, di­ whorls; protoconch unknown. Spiral ornamen- ameter 17.2 mm (Plate 1, fig. 6).

PLATE 1 Figures 1, 2. Haustellum polynematicus (Brown a nd P ilsbry) (X 1 1/2) 1. USNM 445397; height 41.5 mm, d iameter 27.4 mm. Locality: TU 1507, Angostura Formation , Punta Verde, Ecuador. 2. USNM 445398; heigh t 43.0 m m, d ia meter 25.5 mm. Locality: TU 1433, Gatun Formation, Prov. of Colon , P anama. 3, 4. Ceratostoma (Microrhytis) ecuadorium Vokes, n . sp. (X 2) 3. USNM 445399 (holotype); height 23.2 mm, dia mete r 15.5 mm. 4. USNM 445400 (paratype); height 26.8 m m, d iameter 16.9 mm. Locality of both: TU 1507, Angostura Formation , P unta Verde, Ecuad or . 5. Typhis (Talityphis) alatus Sowerby (X 2) USNM 445401; he ight 23.3 mm, d iameter 14.8 mm. Locality: TU 1507, Angostura Formation , P unta Verd e, Ecuad or. 6, 7. Eupleuraolssoni Vokes, n. sp. (X 2) 6. USNM 445402 (holotype); he ight 26.3 mm, diameter 17.2 mm. 7. USNM 445403 (paratype A); height (incomplete) 20.4 mm, d iameter 18.0 mm. Locality of both: TU 1507, Angostura F ormation , Punta Verde , Ecuador . No. 4 Muricidae of Angostura Formation, Ecuador 115

'h 3c1

H,

4b

"ib

b

'b

PLATE I 116 Tulane Studies in Geology and Paleontology Vol. 22

Paratype A: USNM 445403; he ight (incom­ (1941, p. 37*), b ut the Recent species has a plete) 20.4 mm, diameter 18.0 mm; locality same much smoother surface texture; the spiral as holotype (Plate I, Ag. 7). ornamentation appears a lmost as though Paratype B: USNM 643957; height 27.6 mm, the cords are under the surface of the diameter 18.2 mm; locality, Telembi, R io shell, which is draped over them. These in­ Cayapas. Ecuador (figured by Olsson, 1964, pl. 29, Ag. 9). distinct cords are the only spiral ornament; Type locality: TU 1507, Angostura Formation; there are no secondary threads between Punta Verde, large point just east of Rio Verde, them. There a re also no spiral cords de­ or about 30 km east of Rio Esmeraldas, Province veloped on the early whorls of E. murici­ ofEsmeraldas, Ecuador. Jormis, nor is the cord on the shoulder, Occurrence: Angostura Formation, Ecuador. which gives rise to a varical spine between the suture and the shoulder spine, present. Discussion: This is the species that The shoulder spines of E. olssoni are not as Olsson (1964, p. 239) identified as " Eup­ long and are more adapically directed, leura thompsoni Woodring subspecies" but having more the a ppearance of E . the two are no more than gene rically re­ triquetra (Reeve, 1844), another living lated. This new species is much more Panamic species that is sometimes con­ closely related to a second species of Eup­ fused with E. muriciformis. leura that also occurs in the Gatun Forma­ tion, a long with E. thompsoni. a nd it is pos­ This new species is undoubtedly a de­ sible that Olsson had specimens of this un­ scendant of the Early Miocene E. kugleri described form included with E. thomp­ Jung, 1965, described from the Cantaure soni. In any case, the resemblance be­ Formation of the Paraguana Peninsula, tween the Gatun species, d escribed else­ Venezuela. The most noticable difference where in this volume, and E. olssoni, n. between the two forms is the fact that, as sp., is very close. The two may be distin­ Jung noted, on the body whorl of E . kug­ guished by the more scabrous appearance leri "the shoulder disappears" (Jung, 1965, of the Gatun species, which has stronger p . 524). In E. olssoni the shoulder is secondary threads between the major marked on all of the whorls from the ear ­ cords and many axial growth lines that liest up to and including the body whorl by cause the surface of the shell to be a strong cord that gives rise to an extended laciniated. The Gatun species also has one shoulder spine. The shoulder ramp of E . more major spiral cord on the body whorl kugleri is very flattened and the major spi­ and the shoulder spines appear to be ral cord, and resulting spine, is that one at slightly more " upturned," i.e., more adap­ the periphery, so that the overall shape of ically directed. the shell is more oval. The she ll of the new species here de­ scribed is smoother than the Gatun form, and is more like the shell of "typical" Eu­ *The material (Academy of Natural Sciences, pleura. It is an exciting example of Philadelphia, no. 15210) upon which this identifi­ evolutionary gradualism to see the cation is made is truly a mixed bag . There are changes from this species to the somewhat four specimens : two from the Jama Formation more ornamented Gatun form, to the ex­ at Puerto Jama, of which one is E. muriciformis tremely scabrous and nodulose E. nitida a nd the other, although poorly preserved, is (Broderip, 1833), the re presentative of the probably E. pectinata (Hinds, 1844); the other line still living on the coast of Ecuador. The two are from the Canoa Formation at Punta reader is referred to the accompanying Blanca and include one e xa mple of E. murici­ formis and one specimen of Pteropurpura paper (Vokes, 1989) for further discussion centrifuga (Hinds, 1844)! Today the latter on this evolutionary sequence. species does not extend farthe r south than Eupleura olssoni bears a superficial simi­ Panama (Keen , 1971, p. 534) and the more larity to the living Panamic species E. southern e quivalent is P. deroyana Berry, 1968, muriciformis (Broderip, 1833), w hich was endemic to the Galapagos Islands. This occur­ reported from the Jama and Canoa forma­ re nce provides the "missing link" between the tions of Ecuador by P ilsbry and Olsson two present day forms. No. 4 Muricidae of Angostura Formation, Ecuador 117

Subfamily TYPHINAE Cossmann , 1903 water example from the Gatun Formation Genus TYPHIS Montfort, 1810 (Vokes, 1983, pl. 1, fig. 2), so apparently Typhis MONTFORT, 1810, Conchyl. Sysl., v. 2, the species did sometimes make its way p. 614-615. into shallow water. The poor condition of Type species: Typhis tubifer (BruguiCre, the Angostura shell would indicate that it 1792), by original desig. was probably a beach specimen. With occurrences in Ecuador, Panama, Subgenus TALITYPHTS J ousseaume. and the Dominican Republic, in beds rang­ 1882 ing in age from mid-Miocene to mid­ Talityphis JOUSSEAUME, 1882, Rev. Mag. Pliocene, T. alatus is one of the most wide­ Zoo!., (Ser. 2) v 7, p. 338. spread molluscan species in the amph1- Type species: Typhis expansus Sowerby, 1874, American Tertiary. It is, however, never by original desig. common. Even in the Gurabo Formation of the Dominican Republic, the "type area" TvPHIS (TALITYPH!S) AI.ATVS Sowerby of the species, we usually have no more Plate 1, fi g. 5 than one or two specimens at any locality. Typhis alatus G. B. S OWERBY, 1850, Geo!. Soc. London, Qua rt. J our. , v. 6, p. 48, pl. 10. V. LOCALITY DATA fig. 4. Typhis (Talityphis) a lat us Sowerby. OLSSON, The following are Tulane University fos­ 1964, Neogene Mo!!. Northwest. Ecuador, p. sil locality numbers: 141 ; GERTMAN, 1969, T ulane Stud. Geo!. 635. Unnamed formation, roadcut on Mexico Paleont., v. 7, no. 4, p. 159, text-fig. 3 Highway 185, 1.4 miles (2.3 km) south of (holotype); VOKES, 1983, Tulane Stud. bridge over Rio Jaltepec, at Oaxaca-Ver­ Geo!. Paleont., v. 17, no. 4, p. 124, pl. I, figs. acruz state line, Mexico ( University of 1-3; VOKES, 1988. T ulane Stud. Geo!. California. Museum of Paleontology k;cal­ Paleonl., v. 21, no. 1, p. 46, pl. 6, figs. 3, 4; ity A-8124; see Emerson, 1959, p. 6). VOKES, 1989, Bulls. Amer. Paleontology, v. 636. Unnamed formation, roadcut on Mexico 97, no. 332, p. 76, pl. 10, figs. 2-5, text-fig. 20 Highway 185, 1.5 mi!es (2.4 kml south of (holotype ). bridge over Rio Jaltepec, at Oaxaca-Ver· Holotype: British Museum (Natural History) acruz state line, Mexico ( University of GG. 20084; height 29.5 mm, diameter 18.0 mm. California, Museum of Paleontology la"cal­ Type locality: Gura bo Formation; Rio Yaque, ity A-8 125; see Emerson, ibid.*). Dominican Republic (designated by Gertman, 1433. Gatun Formatlon, north side of Boyd­ 1969, p. 160). Roosevelt Highway, clearing behind Ur­ Occurrence: Esmeraldas Beds, Angostura banization San Martin, approximately 0.5 a nd "Picaderos" l Onzole] formations, Ecua­ km east of junction of road to Refineri<1 dor. Unnamed Middle Miocene formation, Do­ Panama, S.A., at Cntivci, Prov. of Col6n. minican Re public. Ga tun Formation, Panama; Panama. Gurabo Formation, Dominican Republic; 1507 Angostura Formation, large point just east Pliocene. of Rio Verde, or approximately 30 km east Figured specimen: USNM 445401; height 23.3 of Rio Esmeraldas, Prov. of Esmeraldas. mm, diameter 14.8 mm; locality TU 1507. Ecuador. Discussion: As has been noted previ­ ously in the Esmeraldas study, one speci­ VI. LITERATURE CITED men of Typhis alatus has been taken from AKERS, W H., 1972. Planktonic foraminifera each of the three units in the Ecuadorian and biostratigraphy of some Neogene forma· Neogene - the Angoslura, the Onzole (as tions, northern Florida and Atlantic Coas1 I Picaderos by Olsson, 1964, p. 141), and the Plain: Tulane Stud. Geol. Paleont., v 9, p. I Esmeraldas Beds (Vokes, 1988, p. 46). l:rn, pis. 1-60, 4 text-figs., 1 map. EMERSON, W K .. 1959, The gastropod genus None are especially well-preserved, but in Pterorytis: Amer :\1us. Novitates, no. 197-t, 8 each case the ide ntification is unmistaka­ ble, as each shows the characteristic elon­ *Although there is a slight discrepancy in the gated ridge anterior to the intervarical mileage/kilometrage, we have searched he tube. As was a lso noted previously (Vokes, area for a third localitv and it does not exist We ibid.), the species is more common in are sure the two Tul~rne localities and the two d eep-water deposits but the re is a shallow· Museum of Paleontology localities an: the same 118 Tulane Studies in Geology and Paleontology Vol. 22

p., 4 text-figs. cent species of Murex s.s. and Haustellum GERTMAN, R. L., 1969, Cenozoic Typhinae (Muricidae: Gastropoda: Mollusca): Rec. (Mollusca:Gastropoda) of the western Atlan­ Australian Mus., Suppl. 8, 160 p., 89 text­ tic region: Tulane Stud. Geo!. Paleont., v. 7, figs., 57 tables. no. 4, p. 143-191, pis. 1-8, 3 lext-figs. VO KES, E. H. , 1964, Supraspecific groups in JUNG, PETER, 1965, Miocene Mollusca from the subfamilies Muricinae and Tritonaliinae the Paraguana Peninsula, Venezuela: Bulls. (Gastropoda:Muricidae): Malacologia, v. 2, Amer. Paleontology, v. 49, no. 223, p. 385- no. 1, p. 1-41 , pis. 1-3. 652, pis. 50-79, 2 tables, 3 text-figs. VOKES, E. H. , 1983, Additions to the Typhinae KEEN, A. M., 1971, Sea shells of tropical west (Gastropoda:Muricidae) of the Gatun Forma­ America. Marine mollusks from Baja Califor­ tion, Panama: Tulane Stud. Geo!. Paleont., nia to Peru. Second Edition. Stanford Uni­ v. 17, no. 4, p. 123-130, pl. I. versity Press, Stanford, California. xiv + VOKES, E. H. , 1988, Muricidae (Mollusca:Gas­ 1064 p., 22 color plates, ca. 4000 figures, 6 tropoda) of the Esmeraldas Beds, northwest­ maps. ern Ecuador: Tulane Stud. Geo!. Paleont., v. OLSSON, A. A., 1964, Neogene mollusks from 21 , no. 1, p. 1-50, pis. 1-6, 15 text-figs., 1 table. northwestern Ecuador. Paleontological Re­ VOKES, E. H., 1989, A new species of Eupleura search Institution, Ithaca, New York. 256 p., (Gastropoda:Muricidae) from the Gatun For­ 38 pis. mation, Panama: Tulane Stud. Geo!. PILSBRY, H. A., and A. A. OLSSON, 1941, A Paleonl., v. 22, no. 4, p. 118-122, pl. I. Pliocene fauna from western Ecuador: Acad. WHITTAKER, J. E., 1988, Benlhic Cenozoic Nat. Sci. Phila., Proc., v. 93. p. 1-79, pis. 1- Foraminifera from Ecuador. British Museum 19. (Natural History), London. xii + 194 p., 25 PONDER. W. F., and E. H. VOKES, 1988, A re­ pls., 11 text-figs. vision of the Indo-West Pacific fossil and Re-

A NEW SPECIES OF EUPLEURA (GASTROPODA:MURICIDAE) FROM THE GATUN FORMATION, PANAMA

EMILYH. VO KES TULANE UNIVERSITY

In the process of determining the iden­ most certainly ance~tral to the rather atypi­ tity of the species cited by Olsson (1964, p. cal E. n itida. 139) as "Eupleura thompsoni Woodring In the Gatun Formation, E. thompsoni is subspecies," from the Angostura Forma­ by far the more common and widespread tion of northwestern Ecuador, it became form. In the Tulane Collections we have obvious that there are two species of Eup­ over 500 specimens from seven localities. leura in the Gatun beds of Panama. One of The new species is much rarer - it has only these is the species named Eupleura been take n at two localities, with just 50 thompsoni Woodring, 1959, and compared specimens. The majority of these (47) are by him to the living E. muriciformis from one locality, TU 958, which must rep­ (Broderip, 1833). However, the similarity is resent a different environment from most much greater to the more spinose and of the Gatun localities, as it was here that long-canaled E. pectinata (Hinds 1844), we also collected a large number of which is found on the west coast of tropical Poirieria (Panamurex) gatunensis (Brown America, from Mexico to Panama. and Pilsbry, 1911) (see Vokes, 1970, p. 42). The second is a smaller form that is more The genus Eupleura is a small group closely related to another species living on with but six Recent species (all we ll-fi­ the west coast of tropical America, Eup­ gured by Rad win and D' Attilio, 1976, pl. leura nitida (Broderip, 1833), character­ 19, figs. 1-7), all found in the Western ized by nodulose intervarical a reas and a Hemisphere. Two of these are living today scabrous surface texture. From the ap­ in the western Atlantic: E. caudata (Say, pearance of the new Gatun species, it is a l- 1822), type of the genus, and E. sulciden-