A new heterodontosaurid from the Redbeds of South Africa showing clear evidence of tooth replacement

A new species, Lanasaurus scalpridens , is erected from a partial lower jaw from the Redbeds of South Africa. The validity of conclusions drawn by other workers in this field is questioned.     

Morphometric discrimination among females of sibling species of Aconophorini (Homoptera: Membracidae)

Abstract. Keys to species of auchenorrhynchous Homoptera are often based on male features, leaving no means for identifying females other than association with males. As a possible solution to this problem, we examined the use of linear discriminant functions derived from morphometric data (ten linear measurements among homologous body landmarks) for distinguishing females in two groups of sibling species in the Neotropical treehopper tribe Aconophorini (Membracidae: Membracinae): (1) Calloconophora caliginosa (Walker) and C.pinguis (Fowler); and (2) Guayaquila minuta (Fowler), G.venezuelensis Dietrich, and Central and South American populations of G.pallescens (Stål). Samples of female specimens identified by association with males were used to derive the discriminant functions. Performance of these discriminant functions as evaluated by jackknifing the data was as follows: 98.11% of the specimens in the first group correctly identified using a combination of three measurements, and 94.94% of the specimens in the second group correctly identified using a combination of ten measurements.     

Pericarp structure and generic affinities in the Anacardiaceae

Pericarp structure is surveyed in 29 genera. Homologous regions termed exocarp, mesocarp and endocarp are established. While exocarp and mesocarp structure show some uniformity, there are two very distinct types of endocarp, designated the Anacardium- type and the Spondias- type . The distribution of these indicates that the current division of the family into five tribes is artificial. The occurrence of the Spondias-type in Canarium , a member of the sister group Burseraceae, suggests that this type is plesiomorphic in the Anacardiaceae. In addition, the presence of the Anacardium- type in Blepharocarya (Blepharocaryaceae) and Orthopterygium Qulianiaceae) further supports the inclusion of these taxa in the Anacardiaceae.     

Use of a Tetrazolium-based Cell Proliferation Assay to Measure Effects of In Vitro Conditions on Perkinsus marinus (Apicomplexa) Proliferation

ABSTRACT. Because the in vitro cell cycle of the apicomplexan oyster pathogen Perkinsus marinus generates cell populations heterogeneous for size and typified by aggregation, both turbidimetric and counting methods for determining population densities and proliferation rates are inaccurate or cumbersome. We show that a commercial, tetrazolium-based cell proliferation assay yields a soluble formazan chromophore upon intracellular reduction by P. marinus . at a rate proportional to cell population biovolume. Using this assay system, we have 1) defined selected culture system parameters which maximize P. marinus in vitro proliferation, 2) assessed selected chemosensitivities, and 3) standardized the assay system for quantification of densities and doubling times of populations propagated with our optimized system. Growth was supported by four tested base media and was maximized in 1:1 DME/Ham's F-12. Temperatures of 10–40° C permitted growth, which was maximized at 35° C. pH 6.0–8.5 permitted growth, which was maximized at 7.0–7.5. Osmolalities of 340–1,930 mOsm supported growth, which was maximized at 790 mOsm. Serum supplements from 1–10% (v/v) did not enhance log phase growth, but enhanced stationary phase metabolic activity in proportion to concentration. Our isolate (ATCC 50439) has a 13 h log phase doubling time when propagated under optimized conditions: 28° C, 800 mOsm, pH 7.0, 1:1 DME/Ham's F-12 medium, 5% (v/v) FBS. It is tolerant of antibacterial agents at concentrations commonly used in vertebrate tissue culture, but is inhibited by several antimycotics at similar concentrations.