Pseudomystus stenogrammus, a new species of bagrid catfish, is described from the Barito River drainage of southern Borneo. The new species is distinguished from all congeners by its colour pattern.

A new species of akysid catfish, Akysis meridionalis, is described from the Barito River drainage of southern Borneo. The new species is distinguished from all congeners by the following combination of characters: 1) upper jaw projects more strongly forward, premaxillary teeth exposed when the mouth is closed; 2) head width 18.2-19.4% SL, body depth at anus 10.7-11.5% SL, depth of caudal peduncle 6.5-6.7% SL, interorbital distance 32-34% HL, length of maxillary barbels 104 110% HL; 3) presence of 5 teeth on posterior edge of the pectoral spine; and 4) colour pattern of dark background with light patches. Akysis meridionalis is the first record of the genus from the Barito River drainage.

Ompok weberi, a poorly-known silurid catfish described from western Borneo, is redescribed from fresh material. It has fewer anal-fin rays than all other congeners (40-48 vs. 50-84). It is mottled brown in coloration, similar to members of the O. leiacanthus species group and some Southeast Asian members of the O. bimaculatus species group, but can be distinguished from them by its non-projecting lower jaw (vs. a projecting lower jaw with an upturned mouth).

The highly specialized akysid catfish genus Breitensteinia is revised; two new species are described. Breitensteinia cessator is described from Sumatra and western Borneo. It can be distinguished by its large, wide‐set eyes and evenly scattered brown spots on the dorsal and pectoral fins. Breitensteinia hypselurus is described from western Borneo. It can be distinguished by its relatively tall neural spines on caudal vertebrae, smooth posterior edge of dorsal spine, short caudal peduncle, and fewer vertebrae. Breitensteinia insignis is sexually dimorphic.

Both three-taxon analysis (3ta) and conventional parsimony analysis (CPA) fall within the cladistic framework. Attempts to exclude 3ta from the general cladistic framework so far seem to amount to declaring CPA as the only permissible analytic technique within cladistics. Critics of 3ta have failed to fully implement it in examples; as a result this criticism is faulty and does not support the claims made. Ultimately, the relative merit of 3ta will be resolved empirically, by comparison of classifications produced from it with classifications using other methods.

This work addresses the current need for a holistic approach in comparative and evolutionary biology and offers numerous applications of the modern methods of phylogenetic systematics and historical ecology, using the North American fish fauna as its case study. This major synthesis, the first published work of its kind, provides a theoretical and methodological foundation for future studies in ichthyology, evolutionary biology, or other fields of comparative biology. Several introductory pieces present major statements of general principles, detailed examinations of the diversity and distributions of North American freshwater fishes, and what is known of their systematic relationships. The rest of the volume's 30 papers then contribute new phylogenetic hypotheses for a significant number of taxa.

This work addresses the current need for a holistic approach in comparative and evolutionary biology and offers numerous applications of the modern methods of phylogenetic systematics and historical ecology, using the North American fish fauna as its case study. This major synthesis, the first published work of its kind, provides a theoretical and methodological foundation for future studies in ichthyology, evolutionary biology, or other fields of comparative biology. Several introductory pieces present major statements of general principles, detailed examinations of the diversity and distributions of North American freshwater fishes, and what is known of their systematic relationships. The rest of the volume's 30 papers then contribute new phylogenetic hypotheses for a significant number of taxa.

Patricia Williams made a number of claims concerning the methods and practise of cladistic analysis and classification. Her argument rests upon the distinction of two kinds of hierarchy: a 'divisional hierarchy' depicting 'evolutionary' descent and the Linnean hierarchy describing taxonomic groups in a classification. Williams goes on to outline five problems with cladistics that lead her to the conclusion that systematists should ''eliminate cladism as a school of biological taxonomy and to replace it either with something that is philosophically coherent or to replace it with 'pure' methodology, untainted by theory'' (Williams 1992, 151). Williams makes a number of points which she feels collectively add up to insurmountable problems for cladistics. We examine Williams' views concerning the 'two hierarchies' and consider what cladists currently understand about the status of ancestors. We will demonstrate that Williams has seriously misunderstood many modern commentators on this subject and all of her ''five persistent problems'' are derivable from this misunderstanding.

A new species of horse-faced loach (genus Acantopsis) is described from Sabah, Malaysia. This new loach is easily differentiated from its congener by its possession of only eight branched dorsal-fin rays and a relatively short snout.

The genus Acanthopsoides Fowler, 1934 is revised; Neacanthopsis Smith, 1945 is placed in the synonymy of Acanthopsoides. In addition to Acanthopsoides gracilis Fowler, 1934 and Acanthopsoides gracilentus (Smith, 1945), four new species are described in the genus. These are A. delphax of the Salween, Chao Phraya and Mekong river basins A. hapalias of the Mekong River basin, A. molobrion from peninsular Thailand, Malaysia and Borneo, and A. robertsi from the Kapuas River basin and adjacent areas, Borneo. The known distribution of the genus includes most of Southeast Asia. Acanthopsoides gracilis, A. gracilentus, and A. delphax are sympatric: A. molobrion and A. robertsi in the Kapuas River basin and A. gracilentus, A. delphax and A. hapalias in the Mekong River basin may be also. The increase in the diversity of Acanthopsoides recognized herein may be indicative of the level of the unknown diversity of the Southeast Asian freshwater fish fauna in general.

The purpose of this application is to designate Cobitis kuhlii Valenciennes in Cuvier & Valenciennes, 1846 as the type species of Acanthophthalmus van Hasselt in Temminck, 1824, a genus of small cobitid fishes from Southeast Asia, commonly known as the coolie loaches, in accordance with accustomed interpretation and usage.The generic name was first published (1823) as Acantophthalmus but this spelling has not been used and its suppression is proposed.

The diploid respiratory-deficient strain of yeast D4-RDII was used to assay PAH and urethane as well as some oxygenated derivatives of PAH and the (aliphatic) epoxide hydrolase inhibitor TCPO for convertogenic (mutagenic) activity. As a positive control, the convertogenic ultimate rat liver carcinogen NOAcAAF was used. PAH and urethane were found inactive as convertogens, TCPO was weakly active, whereas oxygenated electrophilic derivatives of PAH, such as K-region oxides, were found strong convertogens. For comparison, some convertogenic key compounds were assayed for their tumorinitiating activity in mouse skin in the standardized system using TPA as a promoter. PAH were stronger initiators than all oxygenated derivatives of PAH tested. TCPO alone exhibited very weak, if any, initiating activity. It was unable to modify initiation to any significant extent, if administered 5 min prior to administration of an initiator.