Louis S. Kornicker

Ecology and Taxonomy of Recent Bairdiinae (Ostracoda)

Thirteen species belonging to the oslracode genus Bairdia are divided into four groups based on differences and similarities in the morphology of the male copulatory organ. The effect of temperature, salinity, and substrate on the distribution of Bairda is discussed. Four new species of Bairdia and one new species q/Bairdoppilata collected in the Bahamas are described. The carapaces of females have smaller lenght-heigth ratios than those of males. Ecology and taxonomy of Recent Bairdiinae (Ostracoda)

Algal Disintegration of Bahamian Limestone Coasts

Algal-stained rocks of Bahamian coasts are characteristically spotted by small, irregular patches of unstained limestone freshly exposed by the removal of thin flakes of the surface rock. An investigation of this phenomenon shows that the outer algal-stained film of limestone is greatly weakened by boring algae and that it is this part of the rock that scales away, forming the white patches. It is becoming increasingly apparent that boring blue-green algae are among the most important agents of destruction of coast limestone.

Ecology and classification of Bahamian Cytherellidae (Ostracoda)

Four species {three new) of Ostracoda belonging to the family Cytherellidae, collected in the vicinity of Bimini, Bahamas, are described. The influence of water depth, salinity, substrate, and temperature on the distribution of cytherellids is discussed. It is tentatively concluded that cytherellids are restricted to water having salinities above 25 parts per thousand and depths less than 2000 meters. Ecology and classification of Bahamian Cytherellidae (Ostracoda) LOUIS S. KORNICKER. Agricultural and Mechanical College of Texas College Station, Texas

A Bahamian Faecal-Pellet Sediment

ABSTRACT The sediment in the extreme northern portion of the lagoon of the island of Bimini, B.W.I., consists principally of elongate tapered pellets. These distinctive pellets were identified as excrement from Batillaria minima, a marine gastropod abundant in the area of pellet accumulation. Since this gastropod is ecologically restricted, the occurrence of such pellets in situ in the fossil record would be of paleoecological significance.

Ultrastructure of Myodocopid Shells (Ostracoda)

Based on the study of scanning electron micrographs of cross-sections of ostracod shells representing 17 species in genera of the suborders Cladocopina, Halocypridina, and Myodocopina, five primary components are identified in the endocuticle: 1—laminate, 2—columnar, 3—fine granular, 4—coarse granular, 5—homogeneous. Crystalline nodules, rare in vivo, but common in preserved specimens, are considered to represent a secondary component. Preliminary experimentation with sun-dried shells of Vargula hilgendorfii indicates that crystalline nodules form in 10% buffered formalin, a commonly used preservative of plankton. Examination of two growth stages of this species suggests the same general combination of components during ontogeny. Pelagic species of Gigantocypris, Halocypris, Conchoecia, and Macrocypridina have laminate endocuticles, but the pelagic Codonocera polygonia has both laminate and coarse granular components in the endocuticle. Benthonic species may have only one or a combination of any of the five components, but not more than four components in a species.

Distribution of the ostracode suborder Cladocopa, and a new species from the Bahamas

The suborder Cladocopa comprises 3 genera and about 41 living species, which are worldwide in distribution. Most Recent species are limited to the coastal waters of northwestern Europe and the Mediterranean Sea. Fossil occurrences are limited to Europe, with the exception of 4 specimens found near the top of a North Atlantic sediment core, Large forms from the Paleozoic of Europe are referable to the family Leperditellidae rather than to the Cladocopa. Recent Cladocopa are found exclusively in waters of normal salinity, and seem to prefer water temperatures between 4 degrees and 14 degrees C. Although collected occasionally at depths of 1280 to 2600 m., they are usually found in waters less than 500 m. deep. The geologic evidence indicates that the anterior shell concavity was a late acquisition and may be an adaptation permitting more efficient swimming. If so, this may enable the Cladocopa to complete more successfully, and thus may account for the relatively large number of Cladocopa existing at the present time. A new species of the genus Polycope from the Great Bahama Bank is described and figured. Important papers concerning Recent Cladocopa are included in the bibliography.

THE MANDIBLES OF A HALOCYPRID OSTRACODE (HALOCYPRIDINA: HALOCYPRIDAE) – A NEW RECORD OF MANDIBULAR GNATHAL EDGES WITH A “LACINIA MOBILIS”

Abstract A structure resembling the lacinia mobilis in Peracarida (Malacostraca) is described for the coxal gnathal edge of the mandibles in the halocyprid ostracode Spelaeoecia capax. The lacinia mobilis is present at the distal portion of the gnathal edge close to and articulated with the incisor process. Proximal and closely associated with the lacinia, two processes are present. In the center of the gnathal edge, a flat process partly covers two comb-like spines. A molar process (masticatory pad) is present at the proximal end of the gnathal edge. The lacinia mobilis described herein resembles the peracarid lacinia in possessing a number of cusps similar to the cusps of the incisor process, its orientation parallel to the incisor process and the presence of an articular condyle at the basis of the lacinia. The described similarities, however, concern only the left mandible of certain Peracarida where the mandibles are asymmetrical. In Spelaeoecia capax, the mandibles are symmetrical. The lacinia mobilis in certain ostracodes may have evolved independently from that in Peracarida. The term lacinia mobilis is used as a descriptive term only, not implying homology.

Marine and lagoonal deposits in clay dunes, Gulf Coast, Texas

ABSTRACT Thin, light-weight valves of Mulinia lateralis, a lagoonal clam, are found evenly and naturally interbedded in clay at 8 to 33 ft above mean sea level in a clay dune of the mainland shore of Laguna Madre, the coastal lagoon of southwestern Texas. The dune is on the lee shore of a small embayment where the shells seem to have been carried from the parent lagoon by waves and currents and strewn on a mud flat normally barren of subaqueous invertebrates. The shells were then redistributed by wind over the dune. Previously, the only fossils reported from clay dunes have been foraminifera and food animals and shells of aboriginal camp sites. The environment of the occurrence is briefly described, with a review of the origin and development of clay dunes. An irregularly distributed layer of organic and inorganic flotsam deposited on the clay dunes by storm waves is also described, and it is concluded that the M. lateralis shells were not similarly deposited.

Ostracoda from Johnston Atoll, Pacific Ocean, and Proposal of a New Tribe, Bruuniellini (Myodocopina: Cylindroleberididae)

ABSTRACT Two new species of Ostracoda (Myodocopina), Parasterope pacifica Kornicker & Harrison-Nelson and Bruuniella beta Kornicker & Harrison-Nelson, from Johnston Atoll are described and illustrated. The ontogeny of the latter species is also described. In addition, the name Bruuniella alpha Kornicker & Harrison-Nelson is proposed for Bruuniella species A, previously described by Kornicker from the western Atlantic; a supplementary description of the species is provided. A new tribe, Bruuniellini, in the subfamily Cylindroleberidinae, family Cylindroleberididae, is proposed to include the genus Bruuniella, and keys are given to the two tribes in the subfamily and to the four known species of Bruuniella. The adult male of a species of the genus Bruuniella is described for the first time.

Predation of Schistosomiasis Vector Snails by Ostracoda (Crustacea)

An ostracod species of Cypretta is an effective predator in laboratory experiments on 1- to 3-day-old Biomphalaria glabrata, a vector snail of the blood fluke that causes the tropical and subtropical disease schistosomiasis.