Zoological Research

119-125

Authors: Colin GROVES

In this paper, I have introduced the concept of the Evolutionary Species, and shown how it affects the taxonomy of the Artiodactyla of China. The "traditional" taxonomy of the Artiodactyla, which has remained almost unchanged for 100 years, relies on ill-formulated notions of species and subspecies, only slightly modified by the population-thinking of the 1930s. Species are populations (or metapopulations) differentiated by the possession of fixed heritable differences from other such populations (or metapopulations). In the Artiodactyla, there are many more species than "traditionally" recognised; this is by no means a drawback, as it enables the units of biodiversity to be identified in a testable fashion, and brings the taxonomy of large mammals into line with that long practised for small mammals. Species are likely to differentiate where there are natural gaps in the distribution of a genus, such as mountain blocks (for example in the genus Budorcas) or otherwise dissected habitat (for example in the genus Cervus). Natural hybridisation between distinct species is not an uncommon phenomenon, again illustrated well in the genus Cervus, where hybridisation between the elaphus and nippon groups occurs today and evidently occurred in the past, as shown by the distribution of mtDNA.

136-143

Authors: Jing WANG, Guang LI, Guang-Hui QIAN, Jun-Hao HUA, Yi-Quan WANG

The Wnt/β-catenin signaling pathway plays a crucial role in the embryonic development of metazoans. Although the pathway has been studied extensively in many model animals, its function in amphioxus, the most primitive chordate, remains largely uncharacterized. To obtain basic data for functional analysis, we identified and isolated seven genes (Lrp5/6, Dvl, APC, CkIα, CkIδ, Gsk3β, and Gro) of the Wnt/β-catenin signaling pathway from the amphioxus (Branchiostoma floridae) genome. Phylogenetic analysis revealed that amphioxus had fewer members of each gene family than that found in vertebrates. Whole-mount in situ hybridization showed that the genes were maternally expressed and broadly distributed throughout the whole embryo at the cleavage and blastula stages. Among them, Dvl was expressed asymmetrically towards the animal pole, while the others were evenly distributed in all blastomeres. At the mid-gastrula stage, the genes were specifically expressed in the primitive endomesoderm, but displayed different patterns. When the embryo developed into the neurula stage, the gene expressions were mainly detected in either paraxial somites or the tail bud. With the development of the embryo, the expression levels further decreased gradually and remained only in some pharyngeal regions or the tail bud at the larva stage. Our results suggest that the Wnt/β-catenin pathway might be involved in amphioxus somite formation and posterior growth, but not in endomesoderm specification.

151-158

Authors: Salindra K. DAYANANDA, Eben GOODALE, Myung-bok LEE, Jia-Jia LIU, Christos MAMMIDES, Bonifacio O. PASION, Rui-Chang QUAN, J. W. Ferry SLIK, Rachakonda SREEKAR, Kyle W. TOMLINSON, Mika YASUDA

Owls have the potential to be keystone species for conservation in fragmented landscapes, as the absence of these predators could profoundly change community structure. Yet few studies have examined how whole communities of owls respond to fragmentation, especially in the tropics. When evaluating the effect of factors related to fragmentation, such as fragment area and distance to the edge, on these birds, it is also important in heterogeneous landscapes to ask how ‘location factors’ such as the topography, vegetation and soil of the fragment predict their persistence. In Xishuangbanna, southwest China, we established 43 transects (200 m×60 m) within 20 forest fragments to sample nocturnal birds, both visually and aurally. We used a multimodel inference approach to identify the factors that influence owl species richness, and generalized linear mixed models to predict the occurrence probabilities of each species. We found that fragmentation factors dominated location factors, with larger fragments having more species, and four of eight species were significantly more likely to occur in large fragments. Given the potential importance of these birds on regulating small mammal and other animal populations, and thus indirectly affecting seed dispersal, we suggest further protection of large fragments and programs to increase their connectivity to the remaining smaller fragments.

167-175

Authors: Qing-Gang QIAO, Hong-Ji LIANG, Min-Lan BAI, Wei-Hong ZHENG, Jin-Song LIU

Physiological adaptation arises from several fundamental sources of phenotypic variation. Most analyses of metabolic adaptation in birds have focused on the basal metabolic rate (BMR), the lower limit of avian metabolic heat production. In this study, we investigated thermoregulation in three passerine species; the yellow-billed grosbeak Eophona migratoria, white-rumped munia Lonchura striata and black-throated bushtit Aegithalos concinnus, in Wenzhou, China. Metabolic rate was measured using the closed-circuit respirometer containing 3.5 L animal chambers. Body temperature (T_b) was measured during metabolic measurements using a lubricated thermocouple. The minimum thermal conductance of these species was calculated by measuring their T_b and metabolic rates. The yellow-billed grosbeak remained largely normothermic, and the white-rumped munia and black-throated bushtit exhibited variable T_b at ambient temperatures (T_a). Mean metabolic rates within thermal neutral zone were 2.48±0.09 O₂(mL)/g/h for yellow-billed grosbeaks, 3.44±0.16 O₂(mL)/g/h for white-rumped munias, and 3.55±0.20 O₂(mL)/g/h for black-throated bushtits, respectively. Minimum thermal conductance of yellow-billed grosbeak, white-rumped munia and black-throated bushtit were 0.13±0.00, 0.36±0.01, and 0.37±0.01 O₂(mL)/g/h/℃, respectively. The ecophysiological characteristics of these species were:(1) the yellowbilled grosbeak had relatively high T_b and BMR, a low lower critical temperature and thermal conductance, and a metabolic rate that was relatively insensitive to variation in T_a; all of which are typical of cold adapted species and explain its broader geographic distribution; (2) the white-rumped munia and blackthroated bushtit had high thermal conductance, lower critical temperature, and relatively low BMR, all which are adapted to warm environments where there is little selection pressure for metabolic thermogenesis. Taken together, these data illustrate small migratory and resident passerines that exhibit the different characteristics of thermoregulation.

186-188

Authors: Marco ENDRUWEIT

The natural distributional range of the cobitid loach Lepidocephalichthys alkaia is extended into Yunnan Province, China. The modified sexually dimorphic pectoral fin in males of L. alkaia is described.