Migration of wild and captive‐bred Little Bustards Tetrax tetrax: releasing birds from Spain threatens attempts to conserve declining French populations

Populations of the Little Bustard Tetrax tetrax in the farmlands of Europe have declined greatly over the last century. In Western Europe, France now holds the only remaining migratory population, which currently numbers fewer than 300 displaying males. However, the movements of these birds are virtually unknown, in spite of the important implications of this information for the conservation of this species. We identified migratory movements and overwintering areas of French migratory populations, using wild individuals fitted with satellite or radio‐transmitters. Little Bustards completed their migration journey over a relatively short time period (2–5 days), with nocturnal migration flights of 400–600 km per night. All birds overwintered in Iberia. In addition, we tested the consequences of captive rearing on migratory movements. French wild adults and French captive‐bred juveniles behaved similarly with regard to migration, suggesting that hand‐raising does not alter migratory movements. However, birds originating from eggs collected in Spain and reared in western France did not migrate, suggesting a genetic component to migratory behaviour. These results therefore suggest that a conservation strategy involving the release in France of birds hatched from eggs collected in Spain may imperil the expression of migratory movements of the French population. More generally, to maintain the integrity of native populations, the introduced individuals should mimic their migratory movements and behaviour.     

Patterns of morphological evolution in the mandible of the house mouse Mus musculus (Rodentia: Muridae)

The worldwide distributed house mouse, Mus musculus, is subdivided into at least three lineages, Mus musculus musculus, Mus musculus domesticus, and Mus musculus castaneus. The subspecies occur parapatrically in a region considered to be the cradle of the species in Southern Asia (‘central region’), as well as in the rest of the world (‘peripheral region’). The morphological evolution of this species in a phylogeographical context is studied using a landmark‐based approach on mandible morphology of different populations of the three lineages. The morphological variation increases from central to peripheral regions at the population and subspecific levels, confirming a centrifugal sub‐speciation within this species. Furthermore, the outgroup comparison with sister species suggests that M. musculus musculus and populations of all subspecies inhabiting the Iranian plateau have retained a more ancestral mandible morphology, suggesting that this region may represent one of the relevant places of the origin of the species. Mus musculus castaneus, both from central and peripheral regions, is morphologically the most variable and divergent subspecies. Finally, the results obtained in the present study suggest that the independent evolution to commensalism in the three lineages is not accompanied by a convergence detectable on jaw morphology. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 635–647.     

Large‐scale evolutionary trends of Acrochordiceratidae Arthaber, 1911 (Ammonoidea,Middle Triassic) and Cope’s rule

Abstract: Directed evolution of life through millions of years, such as increasing adult body size, is one of the most intriguing patterns displayed by fossil lineages. Processes and causes of such evolutionary trends are still poorly understood. Ammonoids (externally shelled marine cephalopods) are well known to have experienced repetitive morphological evolutionary trends of their adult size, shell geometry and ornamentation. This study analyses the evolutionary trends of the family Acrochordiceratidae Arthaber, 1911 from the Early to Middle Triassic (251–228 Ma). Exceptionally large and bed‐rock‐controlled collections of this ammonoid family were obtained from strata of Anisian age (Middle Triassic) in north‐west Nevada and north‐east British Columbia. They enable quantitative and statistical analyses of its morphological evolutionary trends. This study demonstrates that the monophyletic clade Acrochordiceratidae underwent the classical evolute to involute evolutionary trend (i.e. increasing coiling of the shell), an increase in its shell adult size (conch diameter) and an increase in the indentation of its shell suture shape. These evolutionary trends are statistically robust and seem more or less gradual. Furthermore, they are nonrandom with the sustained shift in the mean, the minimum and the maximum of studied shell characters. These results can be classically interpreted as being constrained by the persistence and common selection pressure on this mostly anagenetic lineage characterized by relatively moderate evolutionary rates. Increasing involution of ammonites is traditionally interpreted by increasing adaptation mostly in terms of improved hydrodynamics. However, this trend in ammonoid geometry can also be explained as a case of Cope’s rule (increasing adult body size) instead of functional explanation of coiling, because both shell diameter and shell involution are two possible paths for ammonoids to accommodate size increase.     

Vegetative morphology and trait correlations in 54 species of Commelinaceae

The morphospace of 54 species of Commelinaceae from nine genera was examined with simultaneous attention to constraints, adaptive hypotheses and relatedness. Eleven morphological traits, including leaf length and width, angle between the leaves and internode distances, were measured for each species and analysed by principal components analysis and nested analysis of variance. The results revealed a significant signal of relatedness in vegetative morphology; genus explained 20–50% of the variance in a single trait. The relationships between some traits are consistent with adaptive explanations. The findings are consistent with the prediction that evolution for optimal phyllotaxis should be relaxed as self‐shading decreases, and that light availability governs leaf size and branching patterns. Constraints potentially explain some trait correlations, and support was found for the hypothesis that structural constraints govern leaf size and internode size correlations. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 257–268.     

Anatomy and lifestyles of Early Cambrian priapulid worms exemplified by Corynetis and Anningvermis from the Maotianshan Shale (SW China)

Accurate information on the anatomy and ecology of worms from the Cambrian Lagerstätten of SW China is sparse. The present study of two priapulid worms Anningvermis n. gen. and Corynetis Luo & Hu, 1999 from the Lower Cambrian Maotianshan Shale biota brings new information concerning the anatomical complexity, functional morphology and lifestyles of the Early Cambrian priapulids. Comparisons are made with Recent priapulids from Sweden (live observations, SEM). The cuspidate pharyngeal teeth of Anningvermis (circumoral pentagons) and the most peculiar radiating oral crown of Corynetis added to the very elongate pharynx of these two forms are interpreted as two different types of grasping apparatus possibly involved in the capture of small prey. Corynetis and Anningvermis are two representative examples of the Early Cambrian endobenthic communities largely dominated by priapulid worms (more than ten species in the Maotianshan Shale biota) and to a much lesser extent by brachiopods. Corynetis and Anningvermis were probably active mud-burrowers and predators of small meiobenthic animals. Likewise predator priapulid worms exploited the interface layer between the seawater and bottom sediment, where meiobenthic organisms were abundant and functioned as prey. This implies that complex prey-predator relationship between communities already existed in the Early Cambrian. This study also shows that the circumoral pentagonal teeth and caudal appendage were present in the early stages of the evolutionary history of the group and were important features of the priapulid body plan already in the Early Cambrian. Two new families, one new genus and new species are introduced and described in the appendix.     

Developmental Endocrinology of the Dipnoan, Neoceratodus forsteri

The development of the pineal, pituitary and thyroid glandsof the extant lungfish, Neoceratodus forsteri, are being studiedboth morphologically and functionally. This paper presents datafrom hatching to 40–52 weeks for a standardised seriesof lungfish, bred at Macquarie University. At hatching, thepineal comprises a single organ attached to the roof of thediencephalon, with well-developed photoreceptor, supportingand ganglion cells. The photoreceptors gradually degenerate,giving way to secretory cells which contain electron dense granules.These latter are immunoreactive to melatonin antibodies anddigestable with protease. The pituitary at hatching comprisesa hollow ball of cells lying beneath the infundibular regionof the hypothalamus. Ultrastructurally, four cell types canbe distinguished by cytoplasmic granule size after the firstfour weeks of development posthatching. By 20 weeks, a furtherthree cell types are recognisable. Inununogold labelling hasidentified corticotropes and melanotropes at four weeks and,at 20 weeks, prolactin cells, thyrotropes and somatotropes alsocan be identified. The thyroid is only just apparent at hatching,containing 2–3 follicles. Thenumbers of follicles increasesgradually, and variably between animals, with age. Iodine uptakein methimazole-treated animals did not exceed that of controlsat any of the three stages tested, indicating a lack of feedbackcontrol between thyroid hormones and pituitary thyrotropes at,or before, 40 weeks of age. Thyroid hormone receptors in theliver at 40 weeks are predominantly immunoreactive to humanTRac antibodies. These findings taken together suggest that,up to 40 weeks post hatching, lungfish development is equivalentto amphibian premetamorphic development. This would be consistentwith lungfish neoteny, but cannot be taken as evidence for neotenyuntil confirmed at later stages of development