AND PALEOECOLOGY OF A NEW SPECIES OF SPHENIA (; MYIDAE) FROM THE PLEISTOCENE OF FLORIDA JACKSON E. LEWIS TULANE UNIVERSITY

CONTENTS Page ABSTRACT ------· ------· ------· ------· ·-- 23 I. INTRODUCTION ______------·---- ______2 3 II. SYSTEMATIC PALEONTOLOGY ______24 III. pALEOECOLOGICAL IMPLICATIONS ______30 IV. LITERATURE CITED ______31

ABSTRACT T 12 S, R 29 E; this site, designated Uni­ The new species, Sphenia tumida} is de­ versity of Florida Locality 5, is approxi­ scribed from the Pleistocene of Flagler mately eight miles west of Bunnell. Al­ County, Florida, an occurrence believed to though the specimens were assigned tenta­ represent the last known appearance of the tively to the genus Cuspidaria in the original genus in the western Atlantic waters im­ report (Lewis, 1964), their true affinities mediately adjacent to the North American are with species of Sphenia} a genus whose continent. Taxonomic characters of the genus living representatives are found in the west­ are reviewed, as are the geographic distribu­ ern Atlantic only in the vicinity of Puerto tion and ecology of living species and the Rico. It is known in eastern North America, geologic distribution of fossil species in however, from fossils in coastal plain de­ eastern North America. Paleoecological in­ posits of Miocene and Pliocene age. The ferences drawn from this occurrence suggest purpose of this paper is to report the young­ a progressive shallowing of the Pamlico em­ est fossil occurrence of the genus in this bayment or lagoon in Flagler County, with a region, to review the ecology and distribu­ proportional increase in the amount of sand tion of selected living species, and to dis­ being transported to the depositional site. cuss the paleoecological implications of this Pleistocene occurrence. The classification of I. INTRODUCTION higher taxa follows, generally, that proposed by Newell ( 1965) for inclusion in Part N While investigating the paleoecology of (Bivalvia) of the Treatise on Invertebrate a Pleistocene marine fauna from Flagler Paleontology. Terms relating to the mor­ County, Florida (Lewis, the writer 1966), phology of the chondrophore are those em­ encountered three articulated individuals and ployed by MacNeil ( 1964) in his discus­ 85 disarticulated complete valves of a species sion of the genus M ya. of bivalve, all of which possess characteristics Acknowledgments: The writer acknowl­ in common quite unlike those of any species edges with deep thanks the comments and currently inhabiting the coastal waters of the suggestions made by the members of the southeastern United States or the northern editorial committee for this paper. He is Gulf of Mexico. The specimens were col­ especially grateful to Dr. H. E. Vokes, Tu­ lected from a bed of blue, highly fossilifer­ lane University, for his assistance and en­ ous, argillaceous, medium sand which con­ couragement, for providing specimens of the stitutes part of the Pamlico Formation and type species Sphenia binghami Turton, for is exposed in the SW 1I 4, SW 1I 4, Sec. 5, comparison, and for making available por-

EDITORIAL COMMITTEE FOR THIS PAPER: A. MYRA KEEN, Department of Geology, Stanford University, Stanford, California KATHERINE V. W. PALMER, Paleontological Research Institution, Ithaca, New York DRUID WILSON, United States Geological Survey, Washington, D. C. 23 24 Tulane Studies in Geology Vol. 6

tions of his catalog of bivalve genera prior Sphaena BLAINVILLE, 1824, Dictionnaire des to its publication (Vokes, 1967). Appre­ Sciences Naturelles, v. 32, p. 344. ciation is extended also to Dr. David Nicol, Type species: Sphaena Birghami Blain­ University of Florida, Dr. R. H. Parker, ville, by monotypy. Texas Christian University, and Dr. T. E. Pulley, Houston Museum of Natural Sciences, rrshaenia/) 11Spaeria/) 11Spenia/) 11Sphaenia/) who examined the material and whose ob­ rrsphena/) rrsphenica/) and rrsyphonia!) servations and comments greatly clarified ("Turton, 1822" or "Blainville, 1824"), the writer's thinking. Dr. J. F. Bridgman, auct. [see Vokes, 1967]. Tulane University, translated a portion of a Description: Shell small, thin, elongate, reference from the original Japanese. Dr. Joseph Rosewater, U.S. National Museum, with left valve slightly smaller than right; kindly provided access to the literature and shape varyingly irregular because of cus­ collections of the Museum's Division of Mol­ tomary nestling habit, but generally with lusca; Mr. Druid Wilson, U.S. Geological narrowed and produced posterior extremity Survey, Washington, D.C., did likewise with slightly reflexed or twisted and with or with­ the Tertiary invertebrate collections of the out slight gap between valves; anterior mar­ Survey; and Mr. J. C. Britton, Jr., U.S. Na­ gin broadly rounded; external prosopon * tional Museum, supplied otherwise inacces­ dominated by irregular concentric growth sible information regarding the ecology of lines; hinge teeth degenerate; ligament in­ the Puerto Rican species S. antillensis. Fi­ ternal; chondrophore narrow and directed nancial support was received under U.S. obliquely posteriorly from its insertion pos­ Public Health Service Grants 3 T1 ES 27 terior to umbo on hinge plate of left valve, 03SI and 5-T01 ES 00027-04, administered terminating beneath corresponding oval to by the Tulane University Program in En­ asymmetrically bisigmoidal depression in vironmental Biology, which enabled the hinge plate of right valve; adductor muscles writer to study both Recent and fossil ma­ anisomyarian, anterior scar oval to elongate terial at the U.S. National Museum during and anterior to antero-ventral in position the summer of 1967. close to margin, posterior scar circular to su~circular, partially beneath or immediately II. SYSTEMATIC PALEONTOLOGY adJacent to posterior extension of hinge plate; pallial line irregular; pallial sinus Class BIVALVIA Linne, 1758 broad and shallow to widely rounded; valve Subclass Neumayr, 1884 interior and internal ventral margin usually smooth. Order MYOIDA Stoliczka, 1870 Discussion: Superficially, some charac­ Suborder MYINA Newell, 1965 teristics of Sphenia approximate those of other genera, particularly some of those in­ Superfamily MYACEA Lamarck, 1818 cluded within the Anomalodesmata, a sub­ Family MYIDAE Lamarck, 1818 class composed largely of forms also adapted to a burrowing habit. In external form, Genus SPHENIA Turton, 1822 Sphenia resembles another eulamellibranch ' Thracia Blainville, 1824, but differs by hav- Sphenia TURTON, 1822, Conchylia Insularum Britannicarum, pp. xvii, 36; A. ADAMS, * "Prosopon" is an inclusive term referring 1851, Proc. Zool. Soc. London, p. 86; H. to th~ surfa~e appearance of a living or fossil and A. ADAMS, 1856, The Genera of Re­ orgamsm. G1ll ( 1949, p. 572) introduced the cent , v. 2, p. 357; DALL, 1898, term to replace "ornamentation " observing that " om_amentation" implies "something' merely dec- Wagner Free Inst. Sci., Trans., v. 3, pt. 4, p. orative, . . . something additional to essentials" 859; GRANT and GALE, 1931, San Diego ~nd, thus, is inappropriate when applied to an Soc. Nat. Hist., Mem. 1, p. 419. mh~rent, often functionally significant, .. ge­ netically maintained," biological character. "Ex­ Type species: Sphenia binghami Turton, ternal" prosopon, in the sense used here, refers 1822 [p. 36, pl. 3, figs. 4, 5, pl. 19, fig. to that prosopon on the exterior surface of the 3], by subsequent designation, Stoliczka, valves, as opposed to that on the interior surface which, on some bivalves, such as members of 1870, Palaeontologia Indica, Ser. 6, v. 3, the Amusiidae, may be prominent and diag­ p. xv; Recent, Torbay, England. nostic. No.1 New Pleistocene Species of Sphenia 25 ing an internal ligament, both umbones type species, S. binghami, this writer must prominently and equally developed, and the join in rejecting Dall's diagnosis of the pal­ umbo of the right valve neither pierced nor lial sinus characteristic of Sphenia as re­ eroded by that of the left. Unlike the septi­ flected in the generic description above. branch Poromya Forbes, 1844, Sphenia is Keen (written communication, March not subequilateral to subtrigonal in shape 1968) observed a close resemblance between and lacks a granulose exterior, radial external the new species of Sphenia and another myid, prosopon, a pearly interior, and unequal Tugonia Gray, 1842. The two are similar in cardinal teeth intimately associated with the shell outline and shape, pallial line and sinus, chondrophores in both valves. Its greatest and adductor muscle scar characteristics; similarity among the Anomalodesmata, how­ however, Sphenia lacks Tugonia's reticulated ever, is with the septibranch Cuspidaria prosopon, broad posterior gap, and chondro­ Nardo, 1840, a fact implied by Dall ( 1898, phore in the right valve, and the beaks on p. 859) in noting the correct generic identity species of Sphenia are neither opisthogyrate of two species from Cuba which d'Orbigny nor located near the posterior shell extremity. assigned initially to 11Sphena'' ( 1846, p. 324). Extant species of Sphenia appear to be Recent authors place both of d'Orbigny's confined to Mediterranean, eastern Atlantic, species in the subgenus Cardiomya A. Adams, Puerto Rican, and Pacific shallow coastal 1864, which exhibits strong radial ribbing, waters. Tebble ( 1966, p. 169) reported the unlike the smooth or concentric sculpture occurrence of the type species, S. binghami, typical of Cuspidaria s.s.; it is with the latter in the Mediterranean and in the eastern At­ that Sphenia, especially the new species de­ lantic from Morocco north to the British scribed herein, may be confused. However, Isles, where it lives "attached by its byssus unlike Cuspidaria s.s., Sphenia lacks a pos­ threads ... just offshore to moderate depths terior lateral tooth in the right valve, has no . . . frequently in [crevices and] holes pre­ internal posterior buttress reinforcing the viously bored and occupied by Hiatella arc­ beaks, and the ligament is not located an­ tica and in the holdfasts of Laminaria." The terior to the beaks. living individuals utilized in Yonge's (1951) Although somewhat similar hinge-line study of this species were collected from structures occur also in some of the genera Hiatella-bored limestone blocks recovered discussed above, the hinge plate and asso­ south of the Calf of Man at a depth of 20 ciated features of Sphenia are most typical fathoms; however, Yonge (1951, p. 387) of those in genera of the Myidae, and among also cited the inclusive bathymetric range these, Sphenia resembles most closely Crypto­ of S. binghami as five to 25 fathoms, figures Conrad, 1843. However, the valves of taken from earlier published reports (Forbes Cryptomya are generally larger and more nearly and Hanley, 1853, p. 193; Jeffreys, 1865, equilateral, the chondrophore is larger, and pp. 71-72). In the mid-1850's, Adams and the pallial sinus, if not completely obsolete, Adams ( 1856, p. 358) noted the character­ is short and narrow. Although Dall ( 1898, istic burrowing habit of the genus "in oyster p. 859) reported the universal occurrence shells and limestone." of a "deep sinus" on Sphenia, Grant and Gale In the western Atlantic, Warmke and Ab­ (1931, p. 419) cited an exception in which bott ( 1961, p. 2 06) reported that S. antil­ the pallial sinus is more like that on Crypto­ lensis Dall and Simpson, 1901, is "Reason­ mya, being "obsolete or very short" (p. 416), ably common from shallow dredgings on the and this observation agrees well with Keen's west and south coasts of Puerto Rico," a lo­ comment ( 1958, p. 206) that Sphenia has cality to which this minute species is ap­ "a shallow but wide pallial sinus." On the parently endemic; although Britton ( 1965) basis of these comments, study of the photo­ collected dead shells from the north coast graphs or line drawings presented by Adams as well (p. 81), he found live specimens and Adams (1855, pl. 95 , fig. 4b ), Brann only in the southwestern, southern, and ( 1966, pl. 6, fig. 35), Dall ( 1898, pl. 35, southeastern coastal waters at depths from fig. 9), Palmer ( 1958, pl. 15, figs. 9, 10), ten to 75 feet, where they inhabit sand and Tebble ( 1966, fig. 90) , and personal ( >80% sand) to sandy mud ( 50-80% observation of the pertinent features ex­ mud) bottoms at salinities ranging from hibited by specimens of S. fragilis and the 35.14%r to 35.71/{c (p. 13). 26 Tulane Studies in Geology Vol. 6

Of the two species inhabiting eastern Pa­ was described from the Oak Grove Sand of cific waters, Sphaenia ovoidea Carpenter, Miocene age in northwestern Florida ( Gard­ 1864, has been reported to occur from the ner, 1936, p. 45). These fossil forms will Aleutians southward to San Diego, Cali­ be discussed more fully following the species fornia (Palmer, 1958, p. 116), although description. Abbott ( 1954, p. 456) cited Panama as the Sphenia tumida Lewis, sp. nov. southernmost limit; Sphaenia fragilis Car­ penter, 1857, has been reported from Oregon Pl. 1, figs. 1-4 to northern Peru (Olsson, 1961, p. 425) and Cuspidaria? sp. Lewis, 1964, Paleoecological throughout its range it is "common" from Study of a Pleistocene Marine Fauna, Flag­ "low tide to 46 fathoms in mud" (Abbott, ler County, Florida [M.S. thesis, Uni­ 1954, p. 455), "Nestling in cavities such as versity of Florida], pp. 32, 34. worm burrows in other shells" (Keen, 1958, p. 207), especially in "abandoned worm Sphenia? sp. Lewis, 1966, Gulf Coast Assn. burrows" (Olsson, 1961, p. 425). However, Geol. Socs., Trans., v. 16, p. 321. Keen (written communication, March 1968) Description: Valves small, white, tumid, has cautioned that published distributional extremely fragile, brittle, and always slightly data for these two species may be somewhat longer than high; antero-central or central misleading, observing that both species "are portion of disc markedly inflated; posterior uncommon throughout their range and rare extremity narrowed and attenuated, almost north of southern California." A western always forming a short rostrum reflexed Pacific form, S. coreanica Habe, 1951, was slightly to the left, inclined dorsa-posteriorly, reported by Habe ( 1961, p. 140) to live and truncated obliquely; posterior gap nar­ nestled around the roots of seaweed in wa­ row; right valve slightly larger and more ters from five to 20 meters deep on the south convex than left. Shape variable; small speci­ shore of Kyushu, although the later edition mens usually suboval with broadly rounded of this work, in English (Habe, 1964, p. anterior and antero-ventral margins, a 205), cited additional uncommon occur­ straight to gently curving postero-ventral rences "in shallow waters from Sagami Bay, margin, and a comparatively long and wide, Honshu to the west coast of K yushtl and gently tapering, abruptly terminated rostrum; Korea." large specimens either essentially the same In eastern North America, the genus is with proportionately narrower rostrum, or represented only by three fossil species, the more or less uniformly subcircular with disc first two of which were reported by Dall more inflated and rostrum more pronounced, ( 1898) as S. dubia (H. C. Lea) , 184 5, from more steeply inclined, proportionately shorter, the Miocene of Virginia and North Carolina and often set off from postero-ventral mar­ ( p. 859), and S. attenuata Dall, 1898, from gin of disc by a shallow indentation. Beaks the Caloosahatchee Marl, a deposit of Plio­ prosogyrate and strongly enrolled, that on cene age exposed in southern Florida ( p. the right valve partly obscured by the 860). The third, S. senterfeiti Gardner, 1936, strongly raised antero-dorsal valve margm;

PLATE 1 Sphenia tumida Lewis, sp. nov. Figures 1 Holotype. Left valve, USNM 645663. 1 a. exterior, X 3; 1b. interior, X 3; 1c. de­ tail of chondrophore, X 4 2 Paratype A. Right valve, USNM 645664. 2a. exterior, X 3; 2b. interior, X 3; 2c. detail of ligamenta! pit, X 4 3 Paratype B. Left valve, USNM 645665. 3a. exterior, X 3; 3b. detail of chondro­ phore, X 4 4 Paratype C. Right valve, USNM 645666. Exterior, X 3 No.1 N ew Pleistocene Species of Sphenia 27

Ia 2a

2b

2c

3b

3a

PLATE 1 28 Tulane Studies in Geology Vol. 6 usually located near midpoint of the length highly curved. Postero-dorsal border of right on large specimens, slightly anterior to mid­ valve overlapping chondrophore and its as­ point on small specimens. Umbones elevated sociated flange on left valve. and prominent, convex to somewhat flat­ Anterior adductor scar faint, an elongated tened, and expanding rapidly. crescent near anterior valve margin; posterior External prosopon variable, tending to be scar subcircular to quadrilateral; if the latter, smoother with numerous, comparatively fine dorso-anterior and ventra-posterior margins and regular, concentrically incised incremen­ frequently slightly concave upward; irregu­ tal lines on small specimens and over earlier, lar, often rough, secondary deposits of shell central portions of disc on large specimens; material occasionally at or near dorsal ex­ growth increments on later portions coarser tremities of both scars. Pallial line approxi­ and increasingly irregular and elevated. mately parallel to ventral 1nargin, the two Prosopon stronger near anterior, postero­ converging somewhat posteriorly; line gen­ ventral, and posterior margins, becoming erally regular and weakly defined, becoming wavy and strongly wrinkled on rostrum, par­ fainter anteriorly. Pallial sinus occasionally ticularly of large specimens. Gray-brown peri­ weak but usually moderately strong; straight ostracum usually preserved near margins of or slightly convex inward; and extending both valves, although most extensive on postero-ventrally from point at or near an­ rostrum. Low ridge emerging from strong terior extremity of posterior scar. Internal posterior slope of umbo and extending to surface smooth or reflecting faintly the ex­ postero-ventral extremity of rostrum, gen­ ternal growth increments, especially near erally well developed on left valves of large ventral margin and on small specimens; individuals, less so on right valves. Umbones chalky to subporcellaneous dorsal to pallial and central part of discs occasionally bi­ line, usually the latter between line and ven­ sected by a shallow, radial groove, generally tral margin; surface dorsal to line seldom directed postero-ventrally to valve margin. granular. Thin, buttress-like secondary shell Hinge teeth lacking. H inge line of right deposits rarely inserted irregularly beneath valve gently curved to almost straight, that hinge plate of either valve. of left valve somewhat straighter although T ype depositories and dimensions: The seemingly depressed immediately posterior holotype and four paratypes have been de­ to beak, where chondrop hore p rojects posited at the U.S. National Museum, Wash­ obliquely posteriorly. Chondrophore short ington, D.C. (USNM), four paratypes at the and narrow with a shallow, elongate, nearly Paleontological Research Institution, Ithaca, parallel-sided, troughlike depression of vary­ New York (PRI), as listed below; dimen­ ing depth ( "fibrum receptacle" of MacNeil, sions are in millimeters. 1964, p. 22) originating beneath the beak Holotype: USNM 645663 (a left valve); and terminating in a slightly to moderately length 9.0, height 7.0, thickness 3.2. Para­ elevated lip ("ventral margin") . Chondro­ type A : USNM 645664 (a right valve); phore continuous with, but set off by one length 9. 0, height 7.1, thickness 3 .1. Para­ or two low ridges ("posterior ridge" ) from, type B: USNM 645665 (a left valve); a short, slightly to moderately raised flange length 10.6, height 9.9, thickness 4.6. Para­ ("posterior furrow") projecting inward from type C: USNM 645666 (a right valve); the hinge line and upward; presence of two length 11.2, height 10.0, thickness 4.3. Para­ ridges (compound "posterior ridge") most type D: USNM 645667 (a left valve, not common on larger specimens, with the an­ figured); length 8.2, height 6.5, thickness terior, lower ridge separated from the pos­ 2.6. Paratype E: PRI 27628 (a right valve, terior, higher one by a marginal notch and not figured); length 6.0, height 5.2, thick­ a shallow, narrow trench curving uninter­ ness 2.0. Paratype F: PRI 27629 (a left valve, ruptedly forward to the hinge line. Liga­ not figured); length 10.5, height 8.4, thick­ menta! pit on right valve, usually asym­ ness 3.8. Paratype G: PRI 27630 (a right metrically bisigmoidal and recessed into valve, not figured) ; length 1 0.6, height 8.1, hinge plate. Slopes of postero-dorsal mar­ thickness 3.3. Paratype H: PRI 27631 (a gins of both valves usually unchanged from left valve, not figured) ; length 11.1, height those of hinge lines, although occasionally 9.7, thickness 3.7. slope near dorsal extremity of rostrum more H ypodigm: Three articulated specimens; No.1 New Pleistocene Species of Sphenia 29 disarticulated complete valves ( 3/ 4 or more and details of the hinge plate and chondro­ of entire valve), 46 left, 39 right; fragments phore of S. coreanica are not sufficiently (primarily hinge plates with associated clear in the original description and figures beaks) , 114 left, 10 5 right. Other than types, to permit ready comparison ( Habe, 1951, p. rnost specimens are housed in the paleon­ 76, text-figs. 3-5), its external prosopon and tological collections of the Florida State Mu­ shape, which is seen to be more rostrate seum, University of Florida, Gainesville, al­ posteriorly in the excellent, later photograph though a few representative individuals have by Habe ( 1961, pl. 63, fig. 10), appear to been placed in the Cenozoic Research Collec­ approach most closely those of S. tumida/ tion, Department of Geology, Tulane Uni­ however, unlike the exterior of the latter, versity.* the umbo of the left valve of S. coreanica Range of dimensions of complete speci­ does not appear as highly elevated as, or mens, in millimeters: Articulated (only one subequal to, that of the right valve. measurable): length 9.0; height 7.3; thick­ Relative to the three fossil species re­ ness 5.4. Disarticulated left: length 12.1 ported from eastern North America, S. (maximum), 5.6 (minimum); height 10.9 tumida is appreciably larger than the Mio­ (maximum), 4.5 (minimum). Disarticu­ cene forms, S. dubia and S. senterfeiti} and lated right: length 11.7 (maximum), 6.0 is more regular in shape and more tumid (minimum); height 9.2 (maximum), 4.9 anteriorly than the latter; its valves differ (minimum). from those of the Pliocene form, S. attenuata} Etymology: Frotn latin, tumidus (swol­ in being lighter and thinner, in possessing len), referring to the outstanding disc char­ a shallower pallial sinus which is not highly actenstlc. and broadly convex inward, and in the po­ Discussion:, Due to the similarity in ex­ sition of the postero-ventral extremity of ternal shape and prosopon exhibited by sev­ the pallial sinus which terminates far back, eral unrelated bivalves which have assumed beneath the posterior adductor scar, rather a burrowing or nestling existence, Sphenia than anteriorly at a point slightly behind tumida resembles externally some species the midpoint of the length of the valve. The of those genera discussed earlier, but posterior extremity of S. attenuata valves is differs in internal characteristics. Among proportionately longer and its margin more extant species of Sphenia} it differs from S. symmetrically and broadly convex, while the binghami} S. antillensis} S. ovoidea} and S. rostrum of S. tumida originates dorsally and fragilis in being more inflated anteriorly, is obliquely truncated. Although described proportionately less elongate, and in having originally from the banks of the Caloosa­ a more conspicuous, narrower rostrum; in­ hatchee River (Dall, 1898, p. 860), DuBar ternally, its pallial sinus is generally less ( 1958, 1962) found no trace of S. attenuata broadly rounded and shallower. In addition, there and reported only 11Sphenia cf. S. at­ S. tumida is much larger than the specimens tenuata Dall" from the Locklin Shell Creek of S. antillensis in the U.S. National Museum collection made farther north, in Charlotte collections, the largest of which approximates County ( 1962, p. 65). Still farther north, the dimensions of the figured holotype from the Pliocene deposits of North St. (USNM 160495), the length measuring Petersburg, Olsson and Harbison ( 1953, p. 4.0 mm, height 2.5 mm, diameter 1.5 mm 150) reported only a single small shell, 4.4 (Dall and Simpson, 1901, p. 474, pl. 55, fig. mm long, of this species. 14) . Although the internal characteristics Of all the Caloosahatchee bivalves, S. tumida is perhaps closest to the form referred ':' Three additional valves (two right and one by Olsson and Harbison ( 1953, p. 65, pl. left) were found in the uncatalogued collections at the U.S. National Museum in material re­ 13, fig. 1) to a new species, Poromya ? ceived from The Johns Hopkins University. The floridana} but it differs in being more in­ label reads "Cuspidaria n. sp., Caloosahatchie flated and in having a more conspicuous beds, Fla., Pliocene," but evidently these speci­ mens were never described and the inadequate rostrum. As mentioned by those authors, P. locality data are probably incorrect. Also found ? floridana is known only from three right in the U.S. Geological Survey collections at the valves and, hence, the critical nature of the National Museum were nine other disarticulated valves, which will be discussed more fully at the left hinge plate and chondrophore is un­ conclusion of the discussion section. known. However, the ligamenta! pit and 30 Tulane Studies in Geology Vol. 6 other details resemble comparable features of subequal units (designated successively in­ S. tumida! and P. ? floridana may well repre­ tervals A, B, C, and D from the top of the sent an earlier form in an evolutionary lin­ sample to the bottom), the writer was able eage which terminated with S. tumida. Pend­ to note changes in these parameters verti­ ing discovery of the crucial missing left cally through the sample. To illustrate, the valve, the designation of Olsson and Harbi­ percentage of excess valves (complete right son should be upheld, but this writer feels valves relative to the total number of com­ that the generic identity of P. ? floridana plete disarticulated valves) computed for will ultimately prove to be Sphenia. Sphenia tumida in each sample interval was, Although Richards ( 1936, 1938, 1939a, from A through D, respectively, 16.7, 56.3, 1939b) analyzed, evaluated, and synthesized 50.0, and 50.0 (p. 325); the unusually low distributional data concerning the Pleisto­ value in interval A was interpreted as due cene marine invertebrate faunas from the to sorting by physical agencies, although the Atlantic and Gulf coastal plains, he recorded species was believed to be indigenous in the no occurrences of species of Sphenia. Among remainder of the sample, especially in its the unidentified specimens in the U.S. Geo­ lowermost two-fifths, represented by in­ logical Survey collections, however, are two tervals C and D. Comparably, abundance closely similar forms from a fo rmation in data computed for S. tumida! relative to all southern Florida called "Unit A" by Olsson mollusks in each interval and expressed also and Petit ( 1964, p. 521 ) and considered in percent, were (again from A through D, by Druid Wilson to be lowermost Pleisto­ respectively) 0.38, 0.85, 1.78, and 2.21 ( p. cene in age (written communication, March, 323); clearly, the species became progres­ 1968). Recovered from USGS Locality 22603 sively less common upward through the near Bermont in Charlotte County, two com­ sample. It is this fact, coupled with the un­ paratively poorly preserved disarticulated equivocally indigenous nature of the species valves (one right and one left) appear in the lowermost intervals, which can be identical to S. tumida! and from USGS Lo­ correlated with the habits and habitats of cality 22846 near Bluefield in St. Lucie living species of Sphenia to interpret further County, seven additional valves (four right, the paleoecological conditions at the Flag­ two left, and one right fragment) resemble ler County depositional site. closely the new species. However, the St. The overall faunal evidence from the Lucie valves are thicker and heavier; the study sample enabled the writer (Lewis, incised lines of their external prosopon are 1966, p. 326) to postulate the following finer, shallower, and more regular; their conditions at the depositional site: "a high­ umbones are more gently rounded with salinity, shallow-water bay environment, with borders, especially anterior, less sharply de­ a predominantly sand or sand-mud substrate; fined; their chondrophores are shorter and considerable wave action; weak currents; and terminated more abruptly ; and their liga­ a minimum water temperature of 50° to menta! pits are not deeply recessed but are 55 ° F." Expanding on this in light of knowl­ borne posteriorly on an elongated, somewhat edge regarding the substrate preference of spoon-shaped structure projecting strongly Recent relatives of S. tumida discussed earlier, postero-ventrally. These specimens 1nay rep­ this genus appears to be well adapted to resent a separate species or subspecies but nestling or burrowing in mud and, presum­ are considered here to be an ecotypic variant ably, S. tumida filled the same ecological of S. tumida! pending accumulation of addi­ niche during the Pleistocene; further, this tional material. species probably represents one of the most conclusive examples in this deposit of preser­ Ill. PALEOECOLOGICAL IMPLICATIONS vation essentially in place. Among the quantitative analytical meth­ If the deposit represents rapid sedimenta­ ods employed by the writer in investigating tion and accumulation, as under storm con­ the paleoecology of the fauna at University ditions in a depression on the bay floor, the of Florida Locality 5 (Lewis, 1966) were greater relative abundance of this species analyses of excess valves and relative abun­ near the bottom of the sample would have dance; as the study sample was subdivided necessitated a deeper burrowing habit than for ease in processing and analysis into four has been reported or observed among living No.1 New Pleistocene Species of Sphenia 31

species of Sphenia. Further, although storm­ Florida: Florida Geol. Survey, Bull. 43, 8.3 induced bottom turbulence may produce de­ pp., 8 figs., 2 pls., 8 tbls. posits of mixed particle sizes, most of the FoRBES, EDWARD, and SYLVAKus HA:\'"LEY, 1853, A history of British Mollusca, and their shells, coarser sand particles settle earlier and are vol. I: London, John Van V oorst, xxx + 486 covered subsequently by sediments in which pp., 64 pls. the finer silt and clay fractions predominate; GARDNER, JuLIA, 1936, Additions to the mollus­ should this have occurred here, it is extremely can fauna of the Alum Bluff Group of Flor­ ida: Florida Geol. Survey, Bull. 14, 82 pp., unlikely that indigenous specimens of S. 10 pls. tumida would be concentrated, as they are, GILL, E. D., 1949, Pmsopon, a term proposed nearer the bottom of the sample. Thus, the to replace the biologically erroneous term ornament: Jour. Paleontology, v. 23, no. 5, deposit probably does not represent rapid p. 572. deposition of this type, and an interpreta­ GRANT, U. S. IV, and H. R. GALE, 1931, Cata­ tion of comparatively slow sedimentation and logue of the marine Pliocene and Pleistocene accumulation seems more reasonable. Under Mollusca of California and adjacent regions: San Diego Soc. Nat. Hist., Mem. 1, 1036 pp., these conditions, specimens of S. tumida 32 pls., 15 text-figs. would have lived in the sandy mud at or HABE, TADASHIGE, 1951, Donacidae and Myidae slightly beneath the water-substrate inter­ in Japan, in Tokubei Kuroda, Illustrated cata­ face, more in accord with the observed pref­ logue of Japanese shells: Kyoto, v. 1, no. 12, pp. 71-76, pl. 12, 5 text-figs. erence of its living relatives, and its abun­ HABE, TADASHIGE, 1961, Coloured illustrations dance would have diminished upward and of the shells of Japan, vol. II: Osaka, Hoiku­ through time due to a decline in the pro­ sha Publ. Co., Ltd., 183 pp., 66 pls., .3 text­ portion of mud in the sediments being in­ figs. [in Japanese]. HABE, T ADASHIGE, 1964, Shells of the western troduced to the depositional site. These con­ Pacific in color, vol. II: Osaka, Hoikusha ditions are explained best by postulating Publ. Co., Ltd., 233 pp., 66 pls .. 3 text-figs. an increasingly higher energy environment JEFFREYS, J. G., 1865, British conchology, vol. through time, such as would result from III: London, John Van Voorst, 393 pp., 9 pls. shallowing, or, less likely, from seasonal KEEN, A. MYRA, 1958, Sea shells of tropical changes. west America; marine mollusks from lower California to Colombia: Stanford, Calif., Stan­ IV. LITERATURE CITED ford University Press, xi + 624 pp., illus. LEWIS, J. E., 1964, Paleoecological study of a ABBOTT, R. T., 1954, American seashells: New Pleistocene marine fauna, Flagler County, York, D. Van Nostrand Co., Inc., xiv + 541 Florida: Unpublished M.S. thesis, University pp., 40 pls., 100 text-figs. of Florida, 221 pp., 1 fig., 31 tbls. ADAMS, HENRY, and ARTHUR ADAMs, 1853- LEWIS, }. E., 1966, Paleoecological study of a 1858, The genera of Recent Mollusca ar­ Pleistocene marine fauna, Flagler County, ranged according to their organization: Lon­ Florida: Gulf Coast Assn. Geol. Socs., Trans., don, John Van Voorst, 660 pp., 138 ,pis. v. 16, pp. 317-327, 2 figs., 4 tbls. . . BRANN, DoRIS C., 1966, Illustrations to Cata­ MAcNEIL, F. S., 1964, Evolution and chstnbu­ logue of the collection of Mazatlan shells" tion of the genus Mya, and Tertiary migra­ by Philip P. Carpenter: Ithaca, N. Y. , Paleon­ tions of Mollusca: U.S. Geol. Survey, Prof. tological Research Inst., 111 pp., 60 pls. Paper 483-G. iv + 51 pp., 11 pls., 3 figs. BRITTON, J. C., JR., 1965, The distribution of NEWELL N. D., 1965, Classification of the selected subtidal marine pelecypods of Puerto Bivalv'ia: Amer. Mus. Nat. Hist. Novitates, Rico and their influence on sediments: Un­ No. 2206, 25 pp., 3 figs., 1 tbl. published M. A. thesis, Texas Christian Uni­ OLssoN, A. A., 1961, Mollusks of the tropical versity, 90 pp., 1 fig. , 3 tbls. eastern Pacific, particularly from the southern DALL, W. H., 1898, Contributions to the Ter­ half of the Panamic-Pacific faunal province tiary fauna of Florida, Pt. IV: Prionodes­ (Panama to Peru); Panamic-Pacific Pelecy­ macea, Nucula to Julia; Teleodesmacea, poda: Ithaca, N. Y., Paleontological Research Teredo to Ervilia: Wagner Free Inst. Sci., Inst., 573 pp., 86 pls. Trans., v. 3, pt. 4, pp. 571-947, pls. 23-35. OLssoN, A. A., and ANNE HARBISON, 1953, Plio­ DALL, W. H., and C. T. SIMPSON, 1901, The cene Mollusca of southern Florida, with spe­ Mollusca of Porto Rico: U.S. Fish Commis­ sion Bull. for 1900, v. 1, pp. 351-524, pls. cial reference to those from North Saint 53-58. Petersburg: Acad. Nat. Sci. Philadelphia, DuBAR, J. R., 1958, Stratigraphy and paleon­ Mon. 8, 457 pp., 65 pls., 2 figs., 2 maps. tology of the late Neogene strata of the OLSSON, A. A., and R. E. PETIT, 1964, Some Caloosahatchee River area of southern Flor­ Neogene Mollusca from Florida and the ida: Florida Geol. Survey, Bull. 40, 267 pp., Carolinas: Bulls. Amer. Paleontology, v. 47, 16 pls., 49 figs., 10 tbls. no. 217, pp. 509-574, pls. 77-83. DuBAR, J. R., 1962, Neogene biostratigraphy D'ORBIGNY, A. D., 1845-1846, Moluscos, in of the Charlotte Harbor area in southwestern RAMON DE LA SAGRA, Historia fisica politica 32 Tulane Studies in Geology Vol. 6

y natural de la Isla de Cuba, tomo V: Paris, RICHARDS, H. G., 1939b, Marine Pleistocene of Arthur Bertrand, Libraire-Editeur, and Ma­ Texas: Geol. Soc. America, Bull., v. 50, no. drid, Istablecimiento tipographico de Don 12, pt. 1, pp. 1885-1898, 3 pls., index map. Francisco de P. Mellado, 376 pp., 28 pls. TEBBLE, NoRMAN, 1966, British bivalve sea­ PALMER, KATHERINE V. W., 1958, Type speci­ shells, a handbook for identification: Lon­ mens of marine Mollusca described by P. P. don, Trustees of the British Museum (Nat. Carpenter from the west coast ( San Diego to Hist.), 212 pp., 12 pls., 110 figs. British Columbia): Geol. Soc. America, Mem. VoKES, H. E., 1967, Genera of the Bivalvia: 76, .376 pp., 35 pls. a systematic and bibliographic catalogue: RICHARDS, H. G., 1936, Fauna of the Pleisto­ Bulls. Amer. Paleontology, v. 51, no. 232, cene Pamlico Formation of the southern At­ 294 pp. lantic Coastal Plain: Geol. Soc. America, WARMKE, GERMAINE L., and R. T. ABBOTT, Bull., v. 47, no. 10, pp. 1611-1656, 4 pls., 1961, Caribbean seashells, a guide to the 1 fig., geol. sketch map. marine mollusks of Puerto Rico and other RICHARDS, H. G., 1938, Marine Pleistocene of West Indian islands, Bermuda and the lower Florida: Geol. Soc. America, Bull., v. 49, no. Florida Keys: Narberth, Pa., Livingston Publ. 8, pp. 1267-1295, 4 pls., 1 fig., index maps. Co., x + 346 pp., 44 pls., 34 text-figs., 19 RICHARDS, H. G., 1939a, Marine Pleistocene of maps. the Gulf Coastal Plain; Alabama, Mississippi, YoNcE, C. M., 1951, Observations on Sphenia and Louisiana: Geol. Soc. America, Bull., v. binghami Turton: Mar. Bioi. Assn. United 50, no. 2, pp. 297-315, 3 pls., index map. Kingdom, Jour., v. 30, pp. 387-392, 2 figs. July 31, 1968 REVIEWS HISTORY OF HYDRAULICS; HISTORY OF THE EXPEDITION UNDER THE COMMAND OF LEWIS AND CLARK HUBERT C. SKINNER TULANE UNIVERSITY HISTORY OF HYDRAULICS, by Hunter HISTORY OF THE EXPEDITION Rouse and Simon Ince. Published by UNDER THE COMMAND OF LEWIS Dover Publications, Inc., New York, 1963, AND CLARK, edited by Elliott Cones. xii + 269 pp., 179 illus., $2.00 Published by Dover Publications, Inc., This is a reprint of the 1957 edition, the New York, 1965, 3 vols., cxlv + 1364 pp., first general history of hydraulics-that 8 maps, index, $6.7 5 branch of science concerned with flow of As early as 1792, Thomas Jefferson formu­ fluids. The authors begin with primitive lated plans for an expedition to the vast efforts to control and regulate waters in western territories and selected Meriwether Mesopotamia, Greece and Egypt, continue Lewis as the leader; this early attempt failed. through the classic Roman period to the In 1801, Jefferson assumed the presidency. Middle Ages and the Renaissance. They By 1803, he succeeded in gaining support then trace in more detail the subsequent de­ from congress for his expedition. On May velopment of experimental and observational 14th, 1804, the party set out from St. Louis hydraulics from Castelli and Torricelli in and for two years traveled westward, up the the early 17th century through the succeeding Missouri River to the continental divide, two centuries, review hydraulic trends in the across the divide to the Columbia River, and early 20th century and recent progress in fluid mechanics, and conclude with An Ap­ descended to the Pacific Ocean. Lewis and praisal of the Science at mid-Century. Clark were acute observers and filled thou­ The reference value is enhanced by inser­ sands of pages with the most complete tion of biographical material and portraits journal of any exploring venture in history. of significant individuals in the development After the death of Lewis in 1809, Nicholas of hydraulics. The text is well illustrated Biddle undertook the task of writing the with reproductions of original diagrams authorized history of the expedition; it ap­ from primary sources. Lists of pertinent peared in 1814. In 1893, Elliott Cones by references follow each chapter and a Chrono­ recourse to the original journals and field logical Table of the Leaders in Hydraulics notebooks much improved the narrative. and Related Fields is appended to the vol­ This is an unabridged republication of the ume. 1893 Cones edition. It is handsomely done.