Corbicula an annotated bibliography 1774 2005

The distribution and biology of Corbicula manilensis in the Arkansas River is discussed. The dredging activities of the U.S. Army Corps of Engineers in the river is related to the appearance and abundance of the bivalve.

Kraemer, L. R. 1977. Designation of deposit sites for dredged material at/in the Arkansas River: Are there biological criteria for appropriate design memoranda? Second International Symposium on Dredging Technology, Texas A&M University. pp. F2 11   F2 20.

A major problem regarding evaluation of dredged material disposal criteria has been that many of the standard tests for water quality are based on the assumption of a relationship between the bulk sediment composition and the pollutional tendencies of the sediment. However, if navigational channels are to be maintained in a major inland river system such as the Arkansas River; if the U.S. Army Corps of Engineers is to monitor discharges, to issue to private companies which mine the river bottom sediments, and to monitor water quality in the river    how are all these things to be done effectively? The results of a study of a 240 mile reach of the Arkansas River, a study initiated by the Little Rock District of the U.S. Army Corps of Engineers to evaluate the possible effects of maintenance dredging on the biota of the river, is considered. A rationale is presented to support an argument that development of protocols including regular collection and evaluation of benthic animals from the river bottom sediments might be used along with accumulated baseline benthic data so as to provide a cheaper, more reliable means of determining appropriate sites for deposit of dredged materials and for maintaining water quality of the river. (The distribution and abundance of Corbicula sp. is discussed).

Kraemer, L. R. 1977. Aspects of the functional morphology of the mantle/shell and mantle/gill complex of Corbicula (Bivalvia: Sphaeroacea: Corbiculidae). Bulletin of the American Malacological Union 1977:25 31.

The gross morphology of the mantle, shell, posterior adductor muscle, and gill is described along with the microscopic anatomy of the siphonal pocket, siphons and related tissues, and gills of Corbicula sp. A preliminary histological examination of the embryos is also reported.

Kraemer, L. R. 1978. Discovery of a new kind of statocyst in the Asian clam, Corbicula: histological analysis and behavioral evaluation. American Zoologist l8(3):647. [Abstract]

In the introduced clam, Corbicula, a pair of small statocysts in a patch of loose connective tissue occupies a position in the animal's midline, just dorsal to the pedal ganglion. Each statocyst has low epithelium and a single statolith which nearly fills its lumen. The two statocysts are conjoined by a clearly defined canal. This is believed to be the first documented report of conjoined statocysts in a mollusc.

In contrast, in indigenous unionacean bivalves such as Lampsilis, each of the pair of statocysts is lateral and posterior to the pedal ganlion. Each is encapsulated and separately innervated by a statocyst nerve from its respective (left or right) cerebral ganglion.

Collateral behavioral studies reveal markedly greater mortality of the introduced sphaeriacean Corbicula than the indigenous unionaceans. It is concluded that the conjoined statocysts of Corbicula facilitate its locomotion. It is hypothesized that conjoined statocysts may prove to be present in other especially active bivalved molluscs as well.

Kraemer, L. R. 1978. Discovery of two distinct kinds of statocysts in freshwater bivalves mollusks: some behavioral implications. Bulletin of the American Malacological Union 1978:24 28.

The statocysts of Lampsilis ventricosa and Corbicula fluminea are described histologically.

Kraemer, L. R. 1978. Corbicula fluminea (Bivalvia: Sphaeriacea): the functional morphology of its hermaphroditism. Bulletin of the American Malacological Union 1978:40 49.

The visceral mass tissues of Corbicula fluminea from the Arkansas and Buffalo Rivers, Arkansas were examined histologically. The oogenic follicles were found to develop and mature before spermatogenic follicles. Changes in the digestive glands' epithelium accompany the appearance and gradual development of the visceral mass stroma and of the oogenic follicles. Development of spermatogenic follicles occurs at branching ends of the earlier appearing oogenic follicles. Maturation of the spermatogenic follicles is accompanied by development of "new" structures herein described and named "follicular ganglia". With the development of follicular ghanglia, masses of mature sperm are present in the surrounding follicles. Oogenic follicles show female gametes of bizarre shape, stretched from their epithelial attachment sites by long peduncles. Many of the female gametes are mingled with mature sperm. A number of oogenic follicles then appear empty or spent. Finally, a number of the follicles contain what appear to be young embryos. The follicular ganglia and the lips of the gonoducts are innervated by nerves of connectives from the main ganglia of the animal. Early embryos as well as later pediveligers come to occupy nearly the total length of the interlamellar space in both inner gills.

Kraemer, L. R. 1979. Juvenile Corbicula: their distribution in Arkansas River benthos. IN: Proceedings of the First International Corbicula Symposium, J. C. Britton, Ed. Texas Christian University Research Foundation (Ft. Worth). pp. 89 97.

The most common and abundant organisms in the sampled Arkansas River bottom were juvenile Corbicula during three sampling series (October 1974, January 1976, and April 1975). The samples were from 56 collection site distributed among l3 stations along a 240 mile study reach (River Mile 283 near Ft. Smith, Arkansas, to Mud Lake at RM 43). Many of the collection sites were at or behind revetments in sand.

Characteristics of the juvenile Corbicula population of the Arkansas River are presented with possible mechanisms for the spread and establishment of the clam in the river. The presence of the byssal thread in juvenile Corbicula is described. Implications for future Arkansas River management policies are discussed.

Kraemer, L. R. 1979. Suprabranchial and branchial shelves of bivalved mollusks: structural functional context of visceral ganglion osphradium and branchial nerves. American Zoologist 19(3):959. [Abstract]

Recent studies of Lampsilis (Bivalvia: Unionacea) and Corbicula (Bivalvia: Sphaeriacea) reveal that the animals' osphradia are paired organs intimately associated with the ventral surface of the visceral ganglion, with the suprabranchial shelf and with the excurrent siphon. These findings call into question earlier studies on bivalve osphradia which assumed a very different neuroanatomy and anitomical context, and which hypothesized a role for the osphradia in regulation of gill cilia.

Further study of histology, neuroanatomy and functional context of suprabranchial and branchial shelves of the aforementioned bivalves allows the conclusions that: (l) the osphradia are more closely associated with the posterior adductor muscle and with the kidneys than they are with the branchial nerves; (2) the paired branchial nerves innervate the branchial shelf and longitudinal muscle there as apparent effectors; and (3) osphradia of gastropods and bivalves probably cannot be homologized.

Kraemer, L. R. 1979. Corbicula (Bivalvia: Sphaeriacea) vs. indigenous mussels (Bivalvia: Unionacea) in the U. S. Rivers: a hard case for interspecific competition? American Zoologist 19(4):1085 1096.

At a time when populations of indigenous river mussels have been dwindling and/or disappearing, the introduced Asian clam, Corbicula, has spread through many U.S. rivers from California to Florida. In the Arkansas River Navigation System, a heavily managed waterway, Corbicula presently has a different "competitive" presence than it does in the relatively unchanged Buffalo River in Arkansas. Comparative studies of both Corbicula and indigenous bivalved molluscs reveal biological bases for the contrasting kinds of benthic faunal change. There are ecologically relevant, distinctive differences between the two kinds of animals: in the mantle/shell and mantle/gill apparatus, in the reproductive complex and neuroanatomy, and in spawning and locomotor behaviors. It is argued that the conservative molluscan characteristics of Corbicula enable it to function in an exclusive, "contradictory" role with indigenous bivalves in a heavily managed waterway, and in a "contrary" competitive role elsewhere. Rationale is presented for incorporating organismic evaluation into studies of competition between distantly related taxa.

Kraemer, L. R. 1980. Neuroanatomical correlates of sexual reproduction in monoecious and dioecious bivalved molluscs. American Zoologist 20(4):89l. [Abstract]

In bivalved molluscs all neuronal soma are not confined to ganglia. Many soma string out along nerves and often form clusters of unknown function in body tissues. Serial section studies show correlation of some soma clusters with sexual reproduction in the monoecious bivalve, Corbicula fluminea. Termed "follicular ganglia" these paired structures are innervated by cerebral or pedal ganglia and invariably appear at confluence of oogenic and spermatogenic follicles. Other evidence shows correlation of development of a pair of mantle ganglia in female Lampsilis ovata ventricosa with onset of sexual maturity and the spawning mechanism of flapping behavior.

Neuroanatomical modifications are clearly shown to be associated with anterior CNS ganglia in the monoecious Corbicula fluminea and with posterior CNS ganglia in female Lampsilis ovata ventricosa. One function of neuroanatomical plasticity of bivalves may be to coordinate differentiation of reproductive tissues and mechanisms.

Kraemer, L. R. 198l. The osphradial complex of two fresh water bivalves: histological evaluation and functional context. Malacologia 20(2):205 216.

From studies based largely on two species of freshwater bivalves, Lampsilis ventricosa ovata (Barnes), a unionacean, and Corbicula cf. C. fluminea (Müller), a sphaeriacean, osphradia are seen to be located within the roof of the exhalant chamber just under the visceral ganglion. In turn the visceral ganglion is positioned anteroventral to the posterior adductor muscle. Extensive serial section study of the osphradial tissues of C. fluminea reveals each osphradium to be comprised of (1) a characteristic epithelium of columnar epithelial cells which lack a basement membrane, but which are profusely innervated by neuronal fibers from (2) clusters of nerve fibers which parallel the base of the epithelium and also send fibers into the visceral ganglion, and (3) clusters of neuronal soma near the base of the epithelium, which send fiber into the visceral ganglion. The clusters of nerve fibers do not constitute a distinct osphradial nerve nor do the neuronal soma constitute a discrete osphradial ganglion.

Three dimensional appearance of the osphradia is that of two narrow, pie wedge shaped organs located at right angles to the longitudinal axis of the animal. The narrowing tips of the organs approach but do not touch in the midline of the ventral surface of the visceral ganglion. Neuroanatomical context of the osphradia is examined in order to test some assumptions implicit in a current hypothesis that bivalve osphradia may function as particle size sensors which serve to regulate activity of gill cilia. Neuroanatomically, the osphradia are closely associated with nerves which supply the posterior adductor muscle and with nerves which supply kidney tissue. The osphradia do not have a close anatomical association with branchial nerves or with the ganglionated roots of those nerves.

A simple but repeated error may account for the inchoate state of the literature on bivalve osphradia. A misrepresentation of osphradia in bivalves as inverted from their normal position may stem from an effort by early workers to homologize bivalve osphradia with those of gastropods. The error may be related to an incorrect assumption by some authors that the bivalve osphradia are associated with the roof of the inhalant rather than exhalant chamber. New hypotheses are needed concerning the function of bivalve osphradia. Hypotheses should incorporate the new information presented here concerning the precise anatomical site, histological organization, three dimensional structure and neuroanatomical context of these paired organs. On the basis of findings presented here, it may be that bivalve osphradia function as light sensors which regulate seasonal behavior or reproductive physiology. Alternatively, it might be that bivalve osphradia function not only in control of fluid movement through the exhalant chamber, but also in adduction of the shell valves.

Kraemer, L. R. 1982. Ontogenetic aspects of biflagellate sperm in Corbicula fluminea (Bivalvia: Sphaeriacea). Transactions of the American Microscopical Society 102(1):88.

Microscopic studies of living sperm of Corbicula fluminea (Müller), along with SEM studies and serial section studies of the gonads, provide converging evidence for the probable sequence of appearance of two kinds of sperm in C. fluminea, and some clues as to their function in the life cycle of the animal. Serial section studies reveal that spermatogenic follicles appear after development of and peripheral to oogenic follicles in the visceral mass. Fully differentiated sperm are located in spherical clusters in the lumen of the spermatogenic follicles, or in hemispheric clusters attached to the follicular epithelium. Studies of living sperm indicate there are two kinds of sperm, one cell type with a wide, long head and the other with a long, slender curved head. All sperm a biflagellate. Wide headed sperm: (l) predominate earlier in a seasonal spermatogenic sequence; (2) are never seen in tight cluster; and (3) exhibit vigorous jerking movements of the head and flagellar movement of large amplitude. The two flagella are not typically coordinated in their movement; and one flagellum is often relatively motionless and extends at an acute angle from the other. Slender headed sperm: (l) predominate later in a seasonal spermatogenic sequence; (2) are frequently grouped in spheres, heads pointing inward, from which individual sperm disengage themselves; and (3) do not show the mobility of the wide headed sperm. SEM studies illuminate the presence of an unusual base for the heads of both sperm types, and confirm the presence of an acrosome in the slender headed sperm. SEM studies further provide evidence that the wide headed sperm are a developmental stage preceding the complete differentiation of the sperm cell.

Kraemer, L. R. 1983. Comparative functional morphology of cilia of Corbicula (Bivalvia: Corbiculidae): possible criteria for effector and putative sensory types. American Malacological Bulletin 1:13 20.

An outstanding feature of the behavior repertoire of Corbicula fluminea (Müller) considered here is the extreme mobility and responsiveness (especially to tactile stimuli) of the siphons. Lips of the anal siphon are notably the most responsive of the siphonal structures. Prolonged microscopic studies of serial sections of the clam's siphonal tissues revealed elaborate innervation of both siphons, but no indication of any sensory apparatus which could in turn be implicated in the distinctive behavior of the siphons. SEM studies of the epithelial surface of the anal siphon did reveal the presence of distinct, widely separated clusters of l2 20, short, upright cilia, which were seen to penetrate the "pebbled" nonmicrovillar epithelial surface. Distinctive structure of the ciliary clusters on the anal siphonal surface is especially evident when compared with SEM of other kinds of cilia in Corbicula (e.g. from gill, gut, mantle, gonoduct surface). These findings, along with behavioral evidence, indicate that the newly discovered, peculiar siphonal cavity tufts may well be the sensory organelles associated with the highly developed tactile sensitivity of the anal siphon in Corbicula.

Kraemer, L. R. 1983. Proto oogamy, embryogenesis and heterochrony in Corbicula fluminea (Bivalvia: Corbiculacea). American Zoologist 23(4):1005. [Abstract]

Unlike other hermaphroditic bivalved molluscs, Corbicula fluminea initiates oogenesis before spermatogenesis, in its ontogeny. During seasonal reproductive cycles of C. fluminea, oogenesis is nearly continuous, but spermatogenesis is episodic and times the cycle. Embryological development follows both self fertilization and cross fertilization, and includes trochophore, veliger, pediveliger and juvenile stages, all of which occur within the inner gills (of the parent clam). Byssus formation follows spawning. It is argues that the foregoing embryological sequence constitutes a "reverberating" reproductive pattern in which thousands of fully differentiated, tiny (250 um) juveniles) are produced. When contrasted with the reproductive and developmental mode in the Pisiidae (Corbiculacea), it appears that heterochrony is importantly involved in the ubiquitous distribution and large biomass of C. fluminea in the disturbed habitat of U.S. rivers.

Kraemer, L. R. 1984. Aspects of the functional morphology of some freshwater bivalve nervous systems. Effects on reproductive processes and adaptation of sensory mechanisms in the sphaeriacea and Unionacea. Malacologia 25(1):221 240.

The soft bodies of molluscs provide the animals with a neuroanatomical context within which the plasticity and variability of the molluscan nervous system can be exploited. For the higher taxa of freshwater bivalves, functional morphology not only of the reproductive systems (in the tradition of Ortmann, 1911), but also of nervous systems and sensors and effectors can account for much adaptive radiation of freshwater bivalves in stable and in rapidly changing habitats. Histological/neuroanatomical and behavioral evidence is presented here concerning several neural entities for (l) the hermaphroditic sphaeriacean bivalve Corbicula fluminea; details of (a) gonoduct innervation; (b) development of "follicular ganglia" along with maturation of oogenic and spermatogenic follicles; and (c) peculiar, conjoined statocysts, are evaluated in their neuroanatomical context. For Lampsilis, details of (a) mante ganglia organization and (b) separate, cislaterally innervated statocysts; and for Carunculina, innervation and behavior of the "thumb twiddling" caruncules, are similarly evaluated.

The foregoing tend to corroborate and amplify characteristics of the reproductive process which distinguish the sphaeriacean and unionacean bivalves. Nervous systems of molluscs do frequently have clusters of neuronal soma at the periphery of even very small nerves, and some of these clusters can be demonstrated (as in the present study) to be associated with peculiar reproductive or locomotor behavior. It seems, therefore, that further investigations of molluscan nervous systems will provide important clues to the environmental past and phylogenetic history of these organisms and also their adaptational future.

Kraemer, L. R. 1984. Ontogeny of the larval foot of Corbicula fluminea (Bivalvia: Corbiculidae). American Malacological Bulletin 2:87. [Abstract]

Dissemination of Corbicula fluminea (Müller), the Asian clam, has been so rapid through the river systems of the U.S. in the past two decades that malacologists must confront the question, how? In this regard, locomotion of the larval stages and the free living juveniles merits focused study. In the present investigation, microscopic serial sections, SEM, fresh tissue dissection and microscopic videotaping were used. It was found that C. fluminea develops a characteristic, barrel shaped trochophore larva, replete with apical tuft, which is retained within the marsupial gill. The longitudinal axis of the body rotates 90 degrees as a pediveliger develops from the trochophore, and the foot anlage appears near the region of the apical tuft. Pediveligers typically are retained in the marsupial gills, where they develop into juveniles about 200 micrometers long. The juveniles exhibit clearly differentiated statocysts and a conspicuous sock shaped foot that is very active in the substratum or in the water column. Sinuses of the juvenile foot are not well developed, and there is no "Hakenform", "Grabstritt", or "Schwellform" behavior, such as one sees in the adult clam. In contrast, the foot engages in vigorous, rapid maneuvers, comprised of extension, "hunching" (of the animal forward onto its extended foot), extension, etc. Alternatively, the comparatively large juvenile foot is quickly withdrawn within the shell valves. SEM examination of the foot revealed that it has a peculiar structure, comprised of a longitudinal series of membranous rings about 2 micrometers wide, which are joined to each other by loose connective tissue. It is quite evidently the "segmenting" rings of tissue that allow the rapid extension and telescoping withdrawal of the juvenile foot. This study indicates that there is structural basis for the distinctive form of locomotion in the juvenile C. fluminea, a basis vastly different from that of the adult clam.

Kraemer, L. R. 1986. Biological basis of behavior in Corbicula fluminea, I. Functional morphology of some trophic activities. IN: Proceedings of the Second International Corbicula Symposium, J. C. Britton, Ed. American Malacological Bulletin Special Edition No. 2. pp. 187 191.

Understanding the functional morphology of trophic activity of Corbicula fluminea (Müller) provides a useful basis upon which to design appropriate control protocols for the clams. Accordingly, this paper reports results of pertinent research. Characteristic, rapid locomotion is accounted for at least in part by (1) the unusual (for a freshwater bivalved mollusc) structural autonomy of the adductor muscles and the "suturing" of the mantle lobes so as to provide a pallial foramen for those muscles; and (2) the recently discovered, conjoined statocysts near the pedal ganglion. Agile locomotion of juvenile clams is produced by (1) precocious differentiation of the statocysts; (2) well developed retractor muscles; and (3) telescoping "laminae" of the juvenile foot, all recently interpreted with videotaping and scanning electron microscopy.

Kraemer, L. R. and M. L. Galloway. 1986. Larval development of Corbicula fluminea (M:uller) (Bivalvia: Corbiculacea): an appraisal of its heterochrony. American Malacological Bulletin 4(1):61 79.

Populations of Corbicula fluminea in intake bays of Arkansas Nuclear One at Russellville, Arkansas, were subjected to a continuing 2 1/2 year study of their gametogenic and ontogenetic processes. Videomicroscopy was especially helpful in working out ontogenetic details, though conventional techniques of microscopic serial sections and scanning electron microscopy (SEM) were also used. In this proto oogamous species it was found that spermatogenesis is synchronously stimulated by temperature rise in the spring and asynchronously stimulated by temperature decline in the fall. Spermatogenesis, in turn, "times" the process of fertilization and ontogeny. Corbicula fluminea seasonally develops many thousands of embryos that characteristically differentiate into blastulae, gastrulae, trochophores, veligers, pediveligers and early and late, straight hinged juveniles.

Kraemer, L. R., M. L. Galloway, and M. E. Gordon. 1986. Aspects of comparative embryogenesis in the Pisidiidae and the Corbiculidae (Bivalvia: Corbiculacea). American Malacological Bulletin 4(1):116. [Abstract]

Microscopical serial sections and freeze cracked scanning electron microscopy (SEM) sections were prepared and examined to work out aspects of the comparative embryology of Corbicula fluminea, Sphaerium striatinum, and Pisidium casertanum, and to investigate events of developmental "timing" in representative species of corbiculid and pisidiid bivalves. Earlier evidence of heterochrony in C. fluminea was confirmed. Retention of trochophore, pediveliger, veliger, early straight hinged juvenile and late straight hinged juvenile stages in C. fluminea within the marsupial gill, contrasts strongly, for example, with their suppression in S. striatinum. In S. striatinum freeze cracked SEM clearly reveals that developmental stages are compressed from gastrula to juvenile; that the juvenile is retained and attached by its placental byssus to the marsupial gill wall, until it attains a size and degree of tissue differentiation very closely approximating that of the parent. SEM confirms an observation made earlier by Mackie, that the "placenta" is not a "placenta." It is exclusively a connective tissue outgrowth of the embryonic foot which constitutes a broad, strong, non vascular holdfast attachment to the marsupial gill wall. It appears that production of the byssal holdfast and its attachment constitute the critical embryonic events for pisidiid bivalves, which allow them to veer away from the more marine/estuarine bivalve like developmental timing preserved in the embryogenesis of C. fluminea.

Kraemer, L. R. and M. Gordon. 1980. Comparison of mollusks retrieved by crowfoot dredge and Ponar grab samples from the White River at St. Charles, Arkansas, with comment on population structure of Corbicula fluminea (Bivalvia: Sphaeriacea). Bulletin of the American Malacological Union 1980:63 67.

Evidence is presented to show: (1) that overlapping collection methods used in this study (crowfoot dredge and Ponar grab) allow community structure of benthic mollusc populations to be fully characterized; (2) that the White River bottom study site is inhabited by an essentially molluscan fauna, until recently comprised of indigenous gastropods and mussels, but now conspicuously including the introduced Asian clam, Corbicula fluminea; (3) that the successful colonization of the site by C. fluminea is associated with disturbance of the substratum and with a diminution of the indigenous fauna; and (4) that C. fluminea presently comprises a substantial portion of the small animals (retrieved by Ponar grab) and of large animals (retrieved by crowfoot dredge). The size range of local populations of C. fluminea now greatly exceeds that of autochthonous molluscs, a feature which is traceable to developmental, behavioral, reproductive and neurobiological peculiarities of the introduced species.

Kraemer, L. R. and M. Gordon. 1980. Size and success: Corbicula (Mollusca: Bivalvia) secret? American Zoologist 20(4):882. [Abstract]

Transects of the White River at a proposed bridge site at St. Charles, Arkansas, were made with a crowfoot dredge. Size of benthic animals retrieved was from 3.5   18.0 cm. Another series of transects was made at the same site with a Ponar dredge. Size of animals in the Ponar samples was 1.0   2.7 cm.

Crowfoot dredge samples included 17 large specimens of Corbicula cf. fluminea. Ponar dredge samples included 7 species of indigenous gastropods and fingernail clams, and numerous small C. fluminea.

Evidence presented allows the conclusions: (1) for adequate characterization of benthic communities, samples from use of both crowfoot and Ponar gear must be evaluated; (2) the White River benthos is a mollusc mollusc rather than mollusc arthropod assemblage; (3) prior to 1966 the benthos was comprised of an indigenous assemblage of small animals (primarily gastropods) and large animals (unionid bivalves); and (4) today, the introduced bivalve C. fluminea is a conspicuous member of both large and small animal benthic communities.

Kraemer, L. R. and S. Lott. 1977. Microscopic anatomy of the visceral mass of Corbicula (Bivalvia: Sphaeriacea). Bulletin of the American Malacological Union 1977: 48 56.

Observations are reported on the gross anatomy and microscopic anatomy of the visceral mass of Corbicula sp. Structures discussed include the external wall of the visceral mass, the pedal muscles, gonadal tissue, digestive system, musculature, nervous tissues, visceral "pit", foot, and sinuses.

Kraemer, L. R., C. Swanson, M. Galloway, and R. Kraemer. 1986. Biological basis of behavior in Corbicula fluminea, II. Functional morphology of reproduction and development and review of evidence for self fertilization. IN: Proceedings of the Second International Corbicula Symposium, J. C. Britton, Ed. American Malacological Bulletin Special Edition No. 2. pp. 193 201.

Results reported in this study of the functional morphology or reproduction and development are based on findings from northwest Arkansas populations of Corbicula fluminea (Müller). Results include verification of the proto oogamous development of the reproductive system in C. fluminea and determination of the role of early innervation of the gonopores and development of follicular "ganglia" which accompany later stages of spermatogenesis; verification of the developmental sequence in oogenesis and the sequential, changing appearance of the oogenic follicles in the visceral mass; determination of characteristics of the biflagellate sperm of C. fluminea as well as evidence that three "kinds" of sperm are not polymorphic sperm but are quite likely several stages in spermatogenesis; and additional evidence of intrafollicular, self fertilization of eggs in the visceral mass of C. fluminea, from sightings of intrafollicular embryos in fixed and fresh tissues.

Krauss, F. l848. Die Sudafrikanischen Mollusken. (Stuttgart).

Corbicula africana sp. nov. is described (p. 8) and figured (pl. l, fig. 8) from the Gauritz River, Zwellendam, Cape Province, South Africa. Corbicula africana b albida ssp. nov. is described on page 8. Corbicula africana olivacea ssp. nov. is also described (p. 8) from the Gauritz River, South Africa. These new taxa are described in the genus Cyrena.

Kreiser, B. R. and J. B. Mitton. 1995. The evolution of cold tolerance in Corbicula fluminea (Bivalvia: Corbiculidae). The Nautilus 109(4):111-112.

Though Corbicula fluminea has become established in numerous northern environments, these locations are protected from winter temperatures by industrial thermal effluents, usually from power plants. As a result, Corbicula is now found in association with power plants in Iowa, Minnesota, Michigan, and Connecticut. Graney et al. (1980) suggested that these thermally protected populations may serve as stepping stones in further northern expansion. One exception to the association with power plants was a population reported in Wisconsin on the St. Croix River. However, there have been no further reports on this location so the success of this population is unknown. These observations suggest that low temperatures are a major restriction on the distribution of Corbicula in North America. We have investigated two of these northern locations. In October 1994, one of us (B.K.) examined an irrigation canal in Lincoln Co., Nebraska (T12N, R26W sec. 30). At that time, a dense population, approximately 120 individuals per square meter, was found in a canal holding only about .3 meters of water. A variety of age classes was present, with individuals less than or equal to 10-15 mm shell length being more abundant than older individuals (25-30 mm shell length). In June 1995 we sampled Highline Lake, which is approximately 30 km northwest of Grand Junction, Colorado, at an elevation of 4697 feet.

Krishnamoorthi, K. P. and S. Rajagopalan. 1969. Survey of mollusk nuisance in some water supplies of Calcutta. Symposium on Mollusca. pp. 746 754.

Krolopp, E. 1976. A szabadhidvegi alsopleisztocen fauna [The lower Pleistocene fauna of Szabadhidveg]. Magyar Allami Foldtani Intezet Evi Jelentese 1976:297 310. [Hungarian with English summary]

The age of the fluviatile formation from gravel and sand pits of Kavicsos Hill, southeast of Lake Szabadhidveg, was determined on the basis of collected molluscs and vertebrate material. The formation was assigned to the uppermost Pliocene (Weiss, 1902) or lowermost Pleistocene (Kormos, 1910; Kadic, 1910). Descriptions are provided for Corbicula fluminalis, Prosothenia sp., Ferrissia pleistocaenica sp. nov., Gastrocopta serotina Lozek, Gastrocopta morarica (Petrbok), Helicodiscus singleyanus (Pilsbry) and Parmacella kormosi sp. nov.

Krolopp, E. 1978. A Corbicula fluminalis (O. F. Müller, 1774) elofordulasa a magyar orszagi pleisztocen uledekekben [Corbicula fluminalis (O. F, Müller, 1774) aus dem ungarischen Pleistozanablagerungen]. Soosiana 6:3 8.

Corbicula fluminalis is reported from Pleistocene strata in the vicinity of Budapest, Hungary.

Kropf-Gomez, D. M. 1993. The potential of the freshwater clam (Corbicula fluminea) for the artificial production of pearls with special emphasis on techniques of pearl seed implantation. Master of Science Thesis, University of Texas at Arlington. xvi+172 pp.

Kruimel, J. H. 19l3. Verzeichnis der von herrn E. C. Abendanon. IN: Celebes gesamelten Süsswasser Mollusken. Bijdragen tot de Dierkunde 19:217 235.

Corbicula loehensis sp. nov. is described (p. 232) and figured (pl. 27, figs. 2, 3) from the southeast coast of Loeha Island, Towuti Lake, Celebes. Corbicula mahalonensis sp. nov. is described (p. 232) and figured (pl. 27, fig. 4) from Lake Mahalona, southeast Celebes. Corbicula masapensis sp. nov. is described (p. 232) and figured (pl. 27, fig. 1) from Lake Masapi, southeastern Celebes. Corbicula towutenis sp. nov. is described (p. 232) and figured (pl. 27, fig. 5) from Lake Towuti, southeast Celebes.

Krylova, L. I. 1966. Mollusks of the genus Corbicula found in Neogene Quaternary deposits of the south central Transural region. Doklady Akademyii Nauk SSSR l70:l58 l59. [Russian. English translation 170:48 49]

Kubly, D. M. and J. J. Landye. 1984. Corbicula fluminea (Bivalvia: Corbiculidae) as a Potential Commercial Fishery in Arizona. U.S. Department of Commerce, NOAA, Project No. CF 4 56 D, Arizona Game and Fish Department. Final Report. 87 pp.

Gametogenesis in lower Colorado River Corbicula appeared to be a nearly continuous process, little affected by seasonal changes in the water temperature, photoperiod or nutrient supplies. Larval presence in clam ctenidia varied seasonally, however, suggesting gamete release and fertilization only occurred under favorable environmental conditions.

Harvesting methods in river reaches having fish, wildlife and esthetic values should be restricted to the use of SCUBA, hand collections and related activities. Any methods which negatively impact water quality should be discouraged.

Kuckyr, R. J. and M. F. Vidrine. 1975. Some clams (Mollusca: Bivalvia) from the Tensas River in Madison Parish, Louisiana. Association of Southeastern Biologists, Bulletin 22(2):61. [Abstract]

Twenty one species of clams were taken from the Tensas River. Of these, two are important since they have not been reported from Louisiana in 50 years; Pleurobema cordatum (Rafinesque) and Elliptio dilatatus (Raf.). Other species are listed. Corbicula manilensis was the most abundant clam in the river.

Kumazawa, N. H. and E. Kato. 1985. Survival of Kanagawa positive strains of Vibrio parahaemolyticus in a brackish water area. Journal of Hygiene 95(2):299 308.

Vibrio parahaemolyticus was observed to overwinter in sediments and to be present in considerable numbers of sediments and Clithon retropictus (Gastropoda) during summer months at a brackish water area along Hashizu Creek, Japan. The highest level of the organisms was 9.3x10⁶ and 2.3x10⁷/100 g in sediments and C. retropictus, respectively. Production of Kanagawa haemolysin was detected in approximately 12% and 20% of strains isolated from sediments and C. retropictus, respectively, at two stations in Hashizu Creek but were not detected at the other three stations. Two haemolysin producing strains were isolated from water samples but none were isolated from Corbicula japonica. These findings suggest that haemolysin producers are preserved principally in sediments and some shellfish in the brackish water areas with restricted salinity conditions.

Kumazawa, N. H., E. Kato, and Y. Nakagawa. 1986. Preliminary analysis on persistence of Vibrio parahaemolyticus in a brackish water clam, Corbicula japonica. Japanese Journal of Veterinary Science 48(2):267 271.

Kumazawa, N. H. and N. Morimoto. 1992. Chemotactic activity of hemocytes derived from a brackish-water clam, Corbicula japonica, to Vibrio parahaemolyticus and Escherichia coli strains. Journal of Veterinary Medical Science 54(5):851-855.

Hemocytes from adult and juvenile specimens of a brackish-water clam, Corbicula japonica, were attracted chemotactically to live cells of Vibrio parahaemolyticus and Escherichia coli strains in a balanced salt solution, which was enhanced significantly in the presence of respective C. japonica plasma. Chemotactic attractions of adult's and juvenile's hemocytes were seen also in artificial seawater at a similar level to those in the balanced salt solution. Chemotactic attractions of juvenile's hemocytes to these strains were lower in level than those of adult's hemocytes. C. japonica plasma seems to facilitate for C. japonica hemocytes to recognize these organisms.

Kumazawa, N. H., N. Morimoto, T. Tanigawa, Y. Tanaka, N. Kasagi, T. Kameie, K. Funaki and A. Iino. 1991. Yamato-shizimi no ketsueki-saibo no keitai to raisozomu koso-kassei [Morphology and activity of lysosomal enzymes in hemocytes of a brackish-water clam, Corbicula japonica]. Venus: Japanese Journal of Malacology 50(3):211-217. [Japanese with English summary]

Hemocytes of an estuarine bivalve, Corbicula japonica, were characterized. Most of the hemocytes were spreading cells similar to those of an estuarine gastropod, Clithon retropictus. C. japonica hemocytes stained for non-specific esterase, acid phosphatase and beta-glucuronidase were 98.7, 35.7 and 55.9%, respectively. Non-specific esterase-positive hemocytes of C. japonica were similar in rate to those of C. retropictus and a marine gastropod, Nerita albicilla. Acid phosphatase-positive hemocytes of C. japonica were lower in rate than those of N. albicilla and higher than those of C. retropictus. Beta-Glucuronidase-positive hemocytes were higher in rate than those of these gastropods. Low activity of acid phosphatase seems to be characteristic in hemocytes of estuarine molluscs.

Kumazawa, N. H., E. Nakagaki, Y. Yonekawa, K. Ikura and N. Morimoto. 1991. Ecological cycle of thermostable direct hemolysin-producing strains of Vibrio parahaemolyticus in a brackish-water area with special reference to molluscs and attached microalgae. Journal of Veterinary Medical Science 53(2):263-267.

Prevalences of thermostable direct hemolysin (TDH)-producing strains in communities of a gastropod mollusc, Clithon retropictus, and a bivalve mollusc, Corbicula japonica, and levels of the strains in attached microalgae and muddy sediments were investigated at a brackish-water area along Hashizu Creek and Togo Pond in Japan. V. parahaemolyticus was detected from attached microalgae at Hashizu Creek in summer months with the highest level of 1.4 x 10⁵ cfu/g. Levels of the organism among 20 animals of C. retropictus and C. japonica at the area varied between non-detectable level and 10³ per mollusc in summer months. TDH was detected from culture supernatants of 11-16% of strains isolated from the algae, sediments and C. japonica and 28% of those isolated from C. retropictus at Hashizu Creek. These evidences suggest that C. retropictus would get TDH-positive strains from the algae.

Kurashige, E. 1945. Study of Korean Corbicula. Part 4. C. fluminea (Müller). Venus, Japanese Journal of Malacology 14:73 81. [Japanese]

Kurashige, E. 1945. Part 5. Ecology and morphological study of Korean Corbicula. Distribution, ecology, and shell shape of the Taiwan shijimi Corbicula fluminea (Müller). Venus, Japanese Journal of Malacology 14:87 96. [Japanese]

Kurelec, B. 1995. Inhibition of multixenobiotic resistance mechanism in aquatic organisms: Ecotoxic consequences. Science of the Total Environment 171(1-3).

Recent evidence indicates that the inherent presence of multixenobiotic resistance (MXR) mechanism in sponges, mussel and fish represents a general biological defense mechanism for their protection against both endogenous and environmental toxins. In aquatic organisms exposed to polluted waters, a P170 glycoprotein pump removes man-made toxic chemicals from cells. Many chemical agents, the 'chemosensitizers', may alter the function of this fragile mechanism. The knowledge that the presence of one xenobiotic may block the pumping of other xenobiotic(s), and hence accelerate their accumulation, which may have important implications on environmental parameters like exposure, uptake, bioaccumulation, and toxicity. In this report we present the results of measurements of MXR-phenotype expression using the 'accumulation' technique and the modulators of MXR, verapamil and staurosporine, demonstrating (1) the interpopulation differences in the level of MXR expression in a marine snail Monodonta turbinata and its induction in specimens exposed to polluted waters, (2) the characteristics of the MXR-expression in a mussel Mytilus galloprovincialis, and (3) how model- or natural-inhibitors of MXR can modulate the no observed effect concentrations (NOEC) of xenobiotics in a fresh water clam Corbicula fluminea and a carp Cyprinus carpio to the observed effect concentrations (OEC).

Kurelec, B., P. Waldmann and R. K. Zahn. 1996. The modulation of protective effects of the multixenobiotic resistance mechanism in a clam Corbicula fluvinea. Marine Environmental Research 42(1-4):383.

Recent evidence indicates that there is a multixenobiotic resistance mechanism (MXRM) in aquatic organisms which represents a general biological defense mechanism for protection against both endogenous and environmental toxicants. In aquatic organisms exposed to polluted waters, this mechanism is inducible. In this paper we show how the state of induction of MXRM in a clam Corbicula fluminea modulates the level of accumulation, or the level of toxic outcomes of exposure to vincristine or acetylaminofluorene (AAF), respectively. Induced clams, i.e. clams freshly collected at a polluted Rhine River site, or control clams exposed for 3 d either to water experimentally polluted with Diesel-2 oil or to Rhine River sediments, accumulated significantly less vincristine than control clams, i.e. clams held in aquaria for 6 weeks. Similarly, the number of single strand breaks (SSB) after AAF-exposure in DNA isolated from gills was significantly lower in induced clams in comparison with SSB found in control clams. Thus, clams may protect themselves from toxic effects by inducing their MXRM. This was supported by evidence that in the presence of staurosporine, the MXRM inhibitor, both found protections were reversed.

Kurihara, H., T. Saiki and M. Hatano. 1997. Suisan shokuhin seibun no gurukoshidaze sogai kassei sukuriningu [Screening of seafood for inhibition of glucosidases]. Nippon Suisan Gakkaishi 63(4):634-635. [Japanese with English summary]

Extract of Japanese seafood was screened for inhibition toward yeast alpha and almond beta -glucosidase activities. The inhibitory activities were evaluated by the agar plate method [Kurihara, et al., Fish. Sci., 60, 759-761 (1994)] using the extract of 20 mg/paper disk. The extract of a fresh brown alga Undaria pinnatifida inhibited both glucosidase activities, while that of dried U. pinnatifida inhibited neither. The extracts of a dried brown alga Laminaria sp. and dried bonito Euthynnus pelamis also inhibited both glucosidase activities. The extracts of brackish-water clam, Corbicula sp. and Japanese littleneck Ruditapes philippinarum inhibited only beta -glucosidase activity. From these results, seafood is a good resource of glucosidase inhibitors.

Kuroda, T. 1938. Studies on Japanese Corbicula. Venus, Japanese Journal of Malacology 8:21 36. [Japanese with English summary]

The systematics and zoogeography of bivalves in the genus Corbicula in Japan are discussed. Corbicula japonica Prime is reported from Honsyu, Sikoku, Kyusyu, and from Aomori in the north to Satuma in the south. Corbicula japonica atrata Reinhardt is reported from Yokohama, Honsyu, Sikoku, Kyusyu ranging from Aomori to Satuma. Corbicula japonica sadoensis Pilsbry is reported from Sado, Hokkaido, and Karahuto. Corbicula japonica transversa von Martens is reported from Yokohama; Kanagawa, Nagasaki, Hukuoka, and Saga prefectures. Corbicula sandai Reinhardt is reported from Hyoto; Siga and Kyoto; Siga and Kyoto prefectures. Corbicula leana Prime is reported from Honsyu; Sikoku; and Kyusyu, ranging from Rikuzen in the north to Satuma in the south. Corbicula awajiensis Pilsbry is reported from Kasyu mura, Awazi Island, and is distributed through Yamaguti; Oita; Okayama; Koti; and Gihu prefectures. Corbicula elatior von Martens is distributed through Rinsinko; Singetumen, Koyo gun, and Zenranando. Corbicula producta von Martens is distributed through Yosyu and Tyuseinando, and throughout Korea. Corbicula papyracea Heude is reported from Sangju, Keisyohokudo; Urusan; Tokuzan, Keisyonando; Kanko; and Tyoen gun, Kokaido. Corbicula fluminea (Müller) is reported from Taiwan ranging from Taihoku to Kosyun. Corbicula subsulcata Clessin is reported from Tansui qawa, Taiwan. Corbicula formosana Dall is reported from Tansui gawa, Taiwan.

Kuroda, T. 1939. Abnormal shells of a Formosan Corbicula. Kiza Geological Notes of Formosa, Taiwan, Chiga Ku 10(4):17 21.

Kuroda, T. and T. Fujita. 1936. Suwako de Sodatta Setashijimi (Corbicula sandai grown in Lake Suwa). Venus, Japanese Journal of Malacology 6(1):60 63. [Japanese]

The growth of Corbicula sandai and Corbicula sandai viola in Lake Suwa is discussed.

Kursalova, V. I. and Y. A. Starobogatov. 1971. Mollusks of the genus Corbicula of Antropogene of north and west Asia and Europe. IN: Molluscs; Trends, Methods and some Results of Their Investigations. Academy of Science of the USSR, Zoological Institute (Leningrad). pp. 93 96.

Corbicula lindholmi sp. nov. is described (p. 94) from the Primorie, Sungari River basin, U.S.S.R. Corbicula ferghanensis is described (p. 95) from the Ferghan River, Uzbeck S.S.R., U.S.S.R.

Kushiro, H. J. Nakamoto, I. Fukui, Y. Yamaguchi, C. Hayashi and Y. Yamumura. 1976. Identification of cholesterol like reactants in shellfish. Proceedings of the Symposium on Chemical Physiology and Pathology 16:221 222.

Kuvajiri, W. 1948. On the young of "Mashijimi", Corbicula leana. Contributions from the Central Fisheries Station, Japan 26:17 22.