A REMARKABLE MELONGENID GASTROPOD FROM THE GATUN FORMATION, P ANAMA BARRY ROTH DEPARTMENT OF GEOLOGY CALIFORNIA ACADEMY OF SCIENCES

The Gatun Formation of the Republic of Diagnosis: Shell of moderate size for the fam­ Panama and the former Canal Zone- N eo­ ily, solid, short-pyriform. Whorls coronate, with gene marine sediments cropping out from thick, upturned spines at the shoulder. Parietal Gatun Lake to the Caribbean coast- has callus extensive posterior to aperture, exposed at been a prolific source of molluscan fossi ls suture on later whorls. Region between shoulder and suture ornamented with prorninenl spiral a nd the object of intensive study for many sculpture consisting of raised cords and series of years (Olsson, 1942; Keen and Thompson, large knobs or beads. Body whorl short. con­ 1946; Woodring, 1957-1973). Oneofthemore stricted anteriorly. Siphonal fasciole broad, enigmatic mollusks discovered there is the prominent, umbilicate, bordered by a keel. oddly adorned gastropod fragment cited by Woodring (1973, pp. 461 , 480, pl. 73, figs. 12, Discussion: The salient feature of this 13) as "xancid? genus?." That author de­ monotypic genus is the presence of complex scribed this puzzling fossil at some length, spiral sculpture on the area between the but its systematic allocation eluded him, and suture and the shoulder of the whorl, in he concluded, "were it not for the columel­ combination with a stout body whorl that is la, it would not be unreasonable to interpret most strongly constricted anteriorly. Ma­ it as a bizarre Vasum. It is by no means ture specimens belonging to the related certain, however, that it is a xancid; it may me longenid genera Melongena Schumach­ possibly b e a cymatid" (Woodring, 1973, p. er, 1817 (type-species M. fasciata Schu­ 480). macher, 18 17 [= Murex melongena Linnae­ A recent collecting venture by Mr. and us, 1758]), Volema Roding, 1798 (type­ Mrs. William D. Pitt of Sacramento, Cali­ species V. paradisiaca Roding, 1798), and fornia, turned up, in addition to many other Pugilina Schumacher, 1817 (type-species P. interesting mollusks, a nearly intact speci­ fasciata Schumacher, 1817 [=Murex mario men of the same species. This specimen Linnaeus, 1758]), sometimes show subdued provides a basis for a fuller, formal descrip­ spiral sculpture between suture and shoul­ tion of the species and an assessment of its der, usually consisting of smooth cords affinities. In addition, a new generic name is more or less interrupted by axial lines of proposed. growth. A puckered sutural band occurs in Thanks ar e due to Drs. Wendell P. Wood­ some species of Melongena - for example. ring, H ar old and Emily Vokes, and Peter U. the familiar Melongena corona (Gmelin, Rodda for advice and consultation in the 1791 )- but consists of raised axial lamellae course of this study. Emily Vokes's thought­ that are former margins of the anal canal. ful critique of the relationships of the new S imilar lamellae border the suture of the genus was especially helpful. Wayne S. Indo-Pacific Volema myristica Roding, Barnett kindly photographed the holotype 1798, and project above the suture as a row under ultraviolet light. of small , hollow spines open toward the aperture. In Melongena lainei (Basterot. Class GASTROPODA 1825), Aquitanian of France, the spiral Order NEOGASTROPODA cords between the suture and shoulder are Supe rfamily BUCCJNACEA sometimes produced into knobs. concave in F amily MELONGENIDAE the direction of growth; but these are never as complex or promine nt as those of Tor­ Genus TORQUIFER Roth, n. gen. quifer, and the body whorl is subconic with Type-species: Torquifer pittorum Roth, its chief region of constriction being medial, n. sp. behind the anterior row of spines. 149 !50 Tulane Studies in Geology and Paleontology Vol. 16

The early whorls of all these forms are and this sometimes leaves projecting traces similar and have 9-13 blunt axial ribs, usu­ below the suture (Plate 1, figure 5). ally showing no carination until about the The Latin name Torquifer - one who third neanic whorl, crossed by smooth, nar­ wears a torques, or necklace- refers to the row spiral cords. These cords extend below singular adornment on the spire. Its gender the shoulder onto the main portion of the is masculine. whorl. In most species of Melongenidae they tend to become weaker with advanc­ TORQUIFER PITTORUM Roth, n. sp. ing growth. Their prominence on the adult Plate 1, figures 1-4, 6 conch is variable within species and within Xancid?, genus? Woodring, 1973, U. S. Geol. populations, but they are typically simple Surv. Prof. Paper 306-E, 461, 480 (as "Family and proportionally weaker than on young Xancidae? Genus?"), pl. 73, figs. 12, 13. shells. By contrast, in Torquifer three of the Diagnosis: As for genus. early subsutural spiral cords are exagge­ rated ("transformed," in the words of Description: Shell of moderate size for the fam­ Woodring, 1973) into rows of knobs as the ily, solid, fairly heavy, short-pyriform. Apex not shell enlarges; other of the cords increase in preserved; five remaining whorls. Spire of mod­ strength. This diagnostic sculpture is most erate height, slightly concave in profile, apical elaborate at the latest stage of growth. angle 75°. First three preserved whorls obtusely The short, broad proportions of the shell shouldered, with nine blunt axial ribs and about five smooth, faint spiral cords between suture are similar to some species of Melongena and shoulder; later whorls coronate. Suture dis­ and Volema, but in many other respects tinct, impressed, undulating between axial ribs. Torquifer resembles the predominantly Eo­ From about fourth whorl on, band of parietal cene genus Cornulina Conrad, 1853 (type­ callus visible at suture, obliquely striated by lines species ?Melongena armigerus Conrad, of growth, tumid. Axial ribs of spire transformed, 1833). A heavy and well defmed parietal on succeeding whorls, into well-spaced, stout. callus is characteristic of many species of upturning, triangular spines at shoulder (I 0 on Cornulina. The callus of adult C. armigera last whorl). Beginning on third whorl, inner (Conrad, 1833) and C. minax (Solander, (most posterior) spiral cord enlarging; bordered in front by narrow, flat-bottomed sulcus; becom­ 1766) is practically as extensive as that of ing nodose, with nodes increasing in prominence Torquifer. Cornu! ina species typically have and developing medial groove, finally develop­ two spiral rows of spines, the anterior row ing into row of closely set, bilobed knobs or weaker and sometimes evanescent. The beads. Other cords on spire also increasing in spines are thick and begin as open, triangu­ prominence, although irregularly, the middle lar scales that seal over with growth, as in one bearing a series of narrow, compressed Torquifer. The region of constriction of the knobs, somewhat hook-shaped in direction of body whorl is in front of the anterior row of aperture; next outboard cord with minor thick­ spines; as in Torquifer, the constricted re­ enings in rhythm with knobs of middle cord. Body whorl almost smooth in front of shoulder, gion bears strongly incised spiral sculpture. convex, with sculpture of irregular, fme, spiral The siphonal fasciole is prominent, usually lirations and even finer lines of growth; con­ bordered by a keel, and at times umbilicate. stricted anterior to middle. Lirations more promi­ A relatively strong anal notch is present. nent and widely spaced on constricted portion.

PLATE! Figures 1-4, 6. Torquifer pittorum Roth, n. sp. Holotype, CASGTC 60375. Locality CAS 58335, Gatun Formation, Republic of Panama; middle Miocene(?). 1, 2, 4. Top, back, and front views (x 1). 3. Color pattern as revealed by ultraviolet light (x 1). Photograph by W. S. Barnett. 6. Detail of spire ornamentation (x 1.25). 5. Cornulina minax campressa Dockery, 1980 (x 1.6). Figured specimen, CAS 60564; length 49.1 mm, diameter 37.7 mm. Locality TU 656, Bashi Formation, road cut on east side of Alabama Highway 69, south bluff of Bashi Creek, about 1.3 mi north of junction at Campbell, Alabama; lower Eocene. No.4 Melongenidfrorn Panama 151

PLATE 1 152 Tulane Stttdies i11 Geology and Paleontology Vol. 16

Just posterior to constriction, a weak spiral row and including the lower facets of, the shoul­ of small. blunt, widely spaced, triangular spines der spines. There is another, less well de­ (four visible on holotype). Siphonal fascicle fined, zone of fluorescence just below the strong, broad. umbilicate. set off from remainder suture. of whorl by a keel. Parietal callus broad, thick, The nearly complete holotype of T. pit· extending well onto face of body whorl and some­ torum leaves no doubt about the assignment what posterior to suture: posterior portion de­ to family Melongenidae. Its overall resem­ tached from whorl between spines of the shoul­ der: weakly and irregularly spirally grooved, blance to the well-known "crown conchs" particularly near anterior end. Aperture subo­ (Melongena, subgenus Rexmela Olsson and . vate, smooth within; anal canal small, located Harbison, 1953: type-species Melongena under knobs of subsutural spiral cord. Outer lip subcoronata Heilprin, 1887), of Florida and broken but apparently not thickened: simple or the Gulf of Mexico, strikes the eye at once. with small marginal denticulations. Anterior Details of the shell, however, as discussed siphonal canal short, oblique, twisted backward above, suggest that its closest phylogenetic and to the right. relationship may not be with Melongena but Length 82.8 mm; diameter 63.6 mrn. with Cornulina. The posteriorly stout body Holotype: California Academy of Sciences whorl, with its faint sculpture and broad, Geology Type Collection 60375. Type locality: CAS 58335, north of Transisth· solid, shoulder spination, strong, umbilicate mian Highway. about 1 km northwest of Saban· siphonal fasciole, and the presence of a ita. Republic of Panama (9°21.25' N, 79"48.75' W). weak series of spines posterior to the pre­ Mr. and Mrs. William D. Pitt, January 1977. medial constriction are all Cornulina-type Occurrence: Lower part of Gatun Formation, characteristics. In forms of Rexmela that Republic of Panama: middle Miocene(?). have them, the anterior rows of spines are Figured specimen: CASGTC 60375 (holotype). borne within or anterior to the constriction Other occurrence: Locality 138c of Woodring of the body whorl; they may not be ho­ (1964. 1973) (= USGS Cenozoic loc. 21956, about mologous to the weak row of spines in T. 100m north of Transisthmian Highway and about 75 m west of road to refinery site on Payardi pittorum. Island, Panama: R. H. Stewart and Anselmo Eocene species ofCornulina- such as C. Mena. 1957): one incomplete specimen (Wood· mina.x compressa Dockery, 1980 , illustrated ring, 1973, pl. 73. figs. 12, 13). here (Plate 1, figure 5) - differ from Tor­ quifer pittorum chiefly in having less tabu­ Discussion: Like certain other mollusks late whorls, with more strongly developed from the Gatun Formation (Pitt and Bar­ anterior spines, and in lacking the elaborate nett, 1979), the holotype of Torquifer pittor­ "necklace" between shoulder and suture. um. shows a color pattern under ultraviolet Torquifer pittorum is larger than any re­ light. The holotype was photographed by corded Cornulina. the method of Pitt and Barnell (1979), with­ It seems, therefore, that a lineage de­ out soaking in sodium hypochlorite. A band scended from the Eocene cornulinas and is visible (Plate 1, figure 3) near the middle preserving many of their fundamental of the body whorl and another, less distinct, characters, persisted in the American trop­ just anterior to the shoulder. extending over ics well into the Neogene. the outer surfaces of the shoulder spines. The function of the bizarre "necklace" of There is a less well defined zone of nuores­ knobs is open to speculation. Its close as· cence just posterior to the siphonal fascicle. sociation with the anal notch - a site of These bands and zone, which fluoresce structural elaboration in certain other more brightly than the rest of the shell, melongenid shells- suggests a function re­ appear dark in the figure because of the lated to elimination. The necklace may photographic reversal process. They prob­ strengthen the shell or divert stress in this ably represent regions of the shell that were region, which might otherwise be a point of more darkly pigmented in life. attack for shell -crushing predators such as As pointed out to me by Emily Vokes, brachyuran crabs (cf. Vermeij, 1978, pp. Cornulina armigera from the Eocene Gos­ 40-46). It may in addition serve to visually port Sand (Joe. TU 306, Little Stave Creek, disrupt the spiral pattern of the top of the Alabama) fluoresces with a similar pattern. shell, thus offering some protection against Placed under ultraviolet light after soaking predators hunting by sight. in sodium hypochlorite, specimens show a The species is named for Mr. and Mrs. bright band on the body whorl, anterior to, William D. Pitt, who collected the type No.4 Melongenidfrom Panama !53 specimen and for many years have favored VERMEIJ, G. J., 1978, Biogeography and adap­ the California Academy of Sciences with tation. Cambridge, Mass., Harvard Univ. valued donations of fossil and Recent Press, 332 p. mollusks. WOODRING, W. P., 1957, Geology and paleon­ tology of Canal Zone and adjoining parts of Panama. Geology and description of Tertiary mollusks (gastropods: Trochidae to Turritelli­ dae): U. S. Geol. Surv. Prof. Paper 306-A, p. LITERATURE CITED 1-145, pis. 1-23. KEEN, A.M., & T. F. THOMPSON, 1946, Notes WOODRING, W. P., 1964, Geology and paleon­ on the Gatun Formation (Miocene), Panama tology of Canal Zone and adjoining parts of Canal Zone: Geol. Soc. America, Bull., v. 57, Panama. Description of Tertiary mollusks no. 12, pl. 2, p. 1260 (abstract). (gastropods: Columbellidae to Volutidae): U. OLSSON, A. A., 1942, Tertiary deposits of north­ S. Geol. Surv. Prof. Paper 306-C, p. 241-297, western South America and Panama: Eighth pis. 39-47. Amer. Sci. Congress, Proc., v. 4, p. 231-287. WOODRING, W. P., 1973, Geology and paleon­ PITT, WILLIAM, & W. S. BARNETT, 1979, tology of Canal Zone and adjoining parts of Some relationships of fossil Gatun gastropods Panama. Description of Tertiary mollusks to their Recent counterparts through the use (additions to gastropods, scaphopods, pelecy­ of fluorescence: Western Soc. Malacol., Ann. pods: Nuculidae to Malleidae): U. S. Geol. Rept.,v.11,p.10. Surv. Prof. Paper306-E, p. 453-539, pis. 67-82.

October 28, 1981

HE VIEWS

THE LANDFORMS OF JAPAN. by Torao interest to both geographers and geologists, Yoshikawa, Sohei Kaizuka, and Yoko especially to those investigating volcanic Ota. Published by the University of phenomena and tectonic activity. Tokyo Press, Tokyo. Japan, 1981. viii+ 22 pp., ill us .. index, folding map, 539.50 (Distributed by Columbia University THE UNITED STATES ENERGY ATLAS, Press, New York. New York) by David J. Cuff and William J. Young. published by The Free Press. a division This volume presents the geomorphology of Macmillan Publishing Co .. Inc .. New of Japan. stressing the growth and dynamic York. New York. 1980. viii + 415 pp .. characteristics of the landforms. Previous­ illus .. index. $75.00 ly. no book in an Occidental language has systematically described the distinctive fea­ The amount and distribution of all energy tures of the four island arcs comprising the sources. including coal, oil. natural gas, Japanese archipelago. Japanese landforms solar power, windpowcr, and biomass. is developed under variable tectonic and de­ described along with hundreds of maps. di­ nudational conditions in recent geological agrams. photographs. charts. and tables as times. Tectonic and volcanic forces are con­ illustration of the distribution of these re­ ::;idered as agents of change. but present­ sources. The work is concerned with an rlay geomorphological processes are not de­ attempt to put the present and future status scribed in detail except where the explana­ of our energy sources into a comprehensi­ tion of these processes is indispensable to ble perspective. It does provide an over­ an understanding of the growth features of view of this vital subject and places it in the landforms. This work will be of major clearer perspective. - - H.CS.