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Due to a lack of distinctive morphological characters, swift taxonomy and phylogeny has always been an area of disagreement. To shed more light on this subject, we reconstructed swift(let) phylogeny based on 1143 bp of mitochondrial cytochrome-b DNA sequence. Although this is not the first attempt to reconstruct swift phylogeny using molecular data, our results show higher support for many of the branches due to our much longer sequences. However, placement of Hydrochous is still unexpected. Implementation of more conservative genetic regions and sampling of more taxa could solve this problem. Most importantly, the Collocaliini resolve as a monophyletic group. The internal structure of the group shows that non-echolocating Collocalia and echolocating Aerodramus form two distinct clades. This is in congruence with earlier classifications based on morphological characters, but in contrast with more recent classifications. (C) 2003 Elsevier Science (USA). All rights reserved.

The tentacled snake Erpeton tentaculatum lives its entire life in fresh water where it feeds mostly on fish. Because the tentacled snake strikes underwater, the physical demands differ from those of air, and require modified methods of prey capture compared to terrestrial snakes. To examine this, we scored the feeding behaviours of five snakes and used multiple high-speed films of two snakes striking fishes. In the pre-strike phase, the snake usually assunled a J-shaped posture with its head turned posteriorly at the neck and its body held straight. The snake waited in such a rigid posture for the fish to move into the very narrow 'window' between turned head and body. Tentacles remained erected, and motionless. The strike was extremely rapid, occurring typically from pre-set J-shaped postures, not from sigmoidal body coils. As the head turned and travelled to the fish, the mouth opened and water collected in the ballooning throat. Significant suction feeding was absent. The fish was secured on buccal teeth and quickly swallowed by unilateral displacements of the jaws. Prey capture and swallowing exhibited specialized modifications of the general snake predatory behaviour to address the hydrodynamic demands of such an underwater strike.

Because fish heads are densely packed with muscles, ligaments, skeletal elements and other structures, transformations in one structure may influence surrounding structures. Transformations occur during phylogeny, ontogeny and as environmentally induced alterations, i.e. phenotypic plasticity. We describe differences in intra- and interspecific transformations of the pharyngeal jaw apparatus of haplochromine cichlids. Using multivariate clustering techniques we trace possible correlations in transformations of anatomical characters of the pharyngeal jaws and surrounding structures. The intraspecific transformation analysis is based on two environmentally induced morphs of Astatoreochromis alluaudi : a molluscivorous morph with a hypertrophied pharyngeal jaw apparatus and an insectivorous one with a non-hypertrophied apparatus. For the interspecific analysis five other haplochromine species from Lake Victoria with diets ranging from insects to molluscs were investigated. Although range in diet are the same, the anatomical ranges differ between A. alluaudi and the species cline. Besides similarities in anatomical changes of the pharyngeal jaw apparatus in the intra- and interspecific cline, differences were also observed. Apparently there are among haplochromines multiple pathways to achieve similar performance. In A. alluaudi architectonic and intrinsic plasticity constraints limit the adaptability of the pharyngeal jaw apparatus. In the species cline, these constraints have been overcome by genetical adaptation.

The Oilbird and many Swiftlet species are unique among birds for their ability to echolocate. Echolocaters may benefit from improved hearing sensitivity. Therefore, morphological adaptations to echolocation might be present in echolocating birds’ middle ears. We studied the functional morphology of the tympano–ossicular chain of seven specimens of four echolocating Swiftlet species and one specimen each of five non-echolocating species. Three dimensional (3D) reconstructions were made from micro-Computer-Tomographic (μCT) scans. The reconstructions were used in functional morphological analyses and model calculations. A two dimensional (2D) rigid rod model with fixed rotational axes was developed to study footplate output-amplitudes and to describe how changes in the arrangement of the tympano–ossicular chain affect its function. A 3D finite element model was used to predict ossicular-chain movement and to investigate the justification of the 2D approach. No morphological adaptations towards echolocation were found in the middle-ear lever system or in the mass impedance of the middle ear. A wide range of middle-ear configurations result in maximum output-amplitudes and all investigated species are congruent with these predicted best configurations. Echolocation is unlikely to depend on adaptations in the middle ear tympano–ossicular chain.

We recently reconstructed the troublesome swiftlet phylogeny using cytochrome- b mitochondrial DNA sequences. The relationship of the giant swiftlet ( Hydrochous gigas ) with swiftlets of the genus Aerodramus was, however, unresolved. In an attempt to clarify this issue, we now incorporated mitochondrial 12S rRNA and nuclear β-fibrinogen intron 7 nuclear DNA sequences with the cyt- b sequences of six swiftlet, two swift, and one hummingbird outgroup species. A partition homogeneity (PH) test, used to determine the congruence of phylogenetic signal between two sets of sequences, suggested that cyt- b and Fib7 sequences were incongruent and therefore should not be combined. However, further analyses revealed that the apparent incongruence was probably due to the high amount of variation in cyt- b sequences. Separate and combined analyses of the three sequences unambiguously placed H. gigas as the sister-group of Aerodramus and supported monophyly of the swiftlets. These results were supported by analyses of combined NADH dehydrogenase subunit-2 (ND2) and cyt- b sequences of H. gigas in combination with sequences previously published by other workers. Recently, it was shown that the pygmy swiftlet ( C. troglodytes )—in our phylogenetic analyses consistently placed with other, non-echolocating, Collocalia species—is in fact able to echolocate. Echolocation thereby lost its value to distinguish between different swiftlet genera. Furthermore, the phylogenetic distribution of echolocation can be explained either by its single evolution at the base of the swiftlets, with subsequent loss, or by independent evolution in Aerodramus and C. troglodytes . Because yet unpublished data suggest that only the auditory nuclei in swiftlet brains show adaptations to echolocation, the latter explanation seems the more likely one.