Rosalie F. Maddocks

Ostracode biostratigraphy of the Permo-Carboniferous of central and north-central Texas; Part I, Paleoenvironmental framework

Permo-Carboniferous Ostracoda have valuable biostratigraphie potential in Texas, if the paleoenvironmental component of the species distributions can be controlled. Collections from 76 outcrop sections in 14 counties provide stratigraphic occurrences for 226 ostracode species, the first comprehensive survey of these faunas. Pattern analysis of a second data set of paleoecologically significant, long-ranging informal taxonomic units yields an inferred coenocline reflecting an onshore-offshore gradient. The position and dispersion of each ostracode species on this independently derived coenocline are presented. The resulting ecological characterizations will help measure the biostratigraphic utility of species and evaluate the applicability of a future biozonation.

Zenker's organ and a new species of Saipanetta (Ostracoda)

S. brooksi n.sp., four other species described, morphology, Holocene, off Bermuda, Mexico, and Galapagos Islands

Ostracode biostratigraphy of the Permo-Carboniferous of central and north-central Texas; Part II; Ostracode zonation

The biostratigraphic utility of Permo-Carboniferous Ostracoda in Central and North-Central Texas is demonstrated by the establishment of six new interval-zones: the Bairdia whitesidei, Kegelites dattonensis, Bairdiacypris acetalata, Waylandella spinosa, Cryptobairdiaforakerensis, and Kindlella aff. K fissiloba zones. All of these zones have good or adequate reliability in offshore, very shallow marine, and (except K fissiloba) deltaic paleoenvironments. The species defining and characterizing these zones have good to high scores on a proposed Index of Biostratigraphic Utility, which measures vertical stratigraphic range, facies independence, biostratigraphic constancy, and ease of recognition of the species. Stratigraphic ranges and position on an independently derived coenocline are presented for 226 species.

Thalassocypridine Ostracoda From Anchialine Habitats of Jamaica

In anchialine cave pools, sinkholes, and wells of Jamaica, three species of the paracypridine tribe Thalassocypridini dominate the podocopid ostracode faunas. Dolerocypria convoluta, new species, Thalassocypria sarbui, new species, and Pontoparta hartmanni Keyser are described. A newly discovered pair of globular organs in T. sarbui may be associated with osmoregulation.

Anatomy of Australoecia (Pontocyprididae, Ostracoda)

Australoecia atlantica Maddocks, n. sp., is described and illustrated. The soft-part anatomy demonstrates that Australoecia McKenzie is correctly classified in the family Pontocyprididae. Abyssocypris van den Bold is a synonym; suggested resemblances to Cardobairdia (van den Bold) are superficial and due to convergence. Australoecia abyssophilia Maddocks is reillustrated. Anatomy of Australoecia (Pontocyprididae, Ostracoda)

One Hundred Million Years of Predation on Ostracods: The Fossil Record in Texas

Cretaceous, Paleogene, and Holocene ostracod assemblages of Texas were systematically surveyed for evidences of predation. Twenty kinds of predation scars include drillholes of naticid and other gastropods, digestive-solution holes, and holes made by unknown animals. Ostracods may provide an important food source for juvenile naticids. Abundance, large size, and smooth carapace favour predation. The earliest naticid drillholes occur in the Cenomanian, although other gastropod holes occur earlier (Albian). Dramatic increases in naticid predation occurred in the Late Campanian and at the Cretaceous-Tertiary boundary, producing high adult mortality rates during the early Cenozoic. Holocene assemblages show somewhat lower predation rates, for which taphonomic, environmental, or evolutionary factors may be responsible. These recorded fluctuations in predation intensity have potential paleoecological, biostratigraphical, and evolutionary applications. Naticid and other gastropod drillholes are most abundant in shallow marine environments, while abundance of solution features characterises upper and midbay facies in coastal estuaries and lagoons. Some evolutionary trends in Cenozoic ostracods may have resulted from increased predation.

New Bairdiidae (Ostracoda) from Tulear, Madagascar

The new species Neonesidea thomassini, Aponesidea ifatyensis, and Mydionobairdia tulearensis are described. Their anatomical characters permit emended diagnoses for these poorly known genera and some speculation on relationships of ornate Bairdiidae.

RECENT BAIRDIIDAE (OSTRACODA) FROM ASCENSION ISLAND

A collection of intertidal algae on rocky shores of Ascension Island has yielded a large population of living ostracodes, most of which belong to four species of Bairdiidae. The shallow benthonic ostracodes of Ascension are almost completely unknown, and no bairdiids have previously been reported. The association appears to have both Mediterranean and Caribbean affinities. Our acquaintance with the ostracode faunas on both sides of the equatorial Atlantic is so slight that it seems appropriate to describe these few bairdiid species, even though the material available by no means represents the entire ostracode fauna of Ascension Island. The most abundant form is a new species of Neonesidea, N. manningi. More noteworthy is the occurrence of a Triebelina closely related to T. raripila (M?ller), a Mediterranean species first described from the Bay of Naples. The third form, Bairdoppilata? species 1, is closely related to a common Caribbean-Antillean species. Another species of Bairdoppilata? is represented by a single specimen. These samples were collected by R. B. Manning and Doug Rogers (Smithsonian Institution), 22 May 1971, and comprise U. S. National Museum Accession No. 294338. The locations are as follows:

New thalassocypridine Ostracoda from anchialine caves of the Loyalty Islands, New Caledonia (Podocopida, Paracypridinae)

Four new species of Ostracoda belonging to the tribe Thalassocypridini are described from anchialine cave pools of the Loyalty Islands of New Caledonia: Dolerocypria iliffei n. sp., Paracypria uberis n. sp., Mungava woutersi n. sp., and Mungava xariessa n. sp. Detailed anatomical comparisons with 36 established species test the soundness of the emerging generic classification of thalassocypridines. Mangalocypria and Mungava are well-defined genera with exclusive, key diagnostic traits. Dolerocypria, Paracypria and Thalassocypria are somewhat less coherent. The essential qualities of Pontoparta and Parapontoparta remain elusive because of the heterogeneity of species referred to those nominal genera. Emended diagnoses are offered for the tribe Thalassocypridini and for the genera Dolerocypria, Paracypria, and Mungava.

Multivariate Analysis of Leg Morphology of Macrocyprididae

The fifth, sixth, and seventh legs and furcae of cypridacean ostracods are widely supposed to have considerable taxonomic significance and are relatively easy to dissect and illustrate. Nevertheless, some of the characters used in the past to diagnose new taxa have turned out to be invariant and, hence, without taxonomic importance, while many others are strongly correlated with each other or directly dependent on general size and, thus, not independent in their taxonomic significance. R-mode cluster and principal components analyses can be used to evaluate the independence of characters, so that the most appropriate characters may be selected for taxonomic and evolutionary applications. To demonstrate this, 112 characters have been measured on these appendages and carapace for 71 species of Macrocyprididae, a relatively small and homogeneous family. The results show the potential of such methods for improving ostracod taxonomy. Q-mode cluster analysis of the same data provides evidence to test the generic classification of these species based on the carapace and subjective judgments. In general, the results confirm the prevailing opinion that the furcae and male fifth limbs offer more taxonomic information than the female fifth limb, sixth limb, and seventh limb. However, a few previously ignored characters may have taxonomic value, masked at present by possible non-linearity of their relationships.