Macroecological Patterns of Climatic Niche Breadth Variation in Lacertid Lizards

Measuring climatic niche position and breadth may help to determine where species can occur over space and time. Using GIS-based and phylogenetic comparative methods, we investigated global patterns of variation in climatic niche breadth in lacertid lizards to test the following three hypotheses about climatic niche widths. First, does a species' temperature or precipitation niche breadth relate to its temperature or precipitation niche position(the mean value of annual mean temperature or annual precipitation across sampled localities in the range of each species)? Second, are there trade-offs between a species' temperature niche breadth and precipitation niche breadth? Third, does a species' temperature or precipitation niche breadth relate to altitude or latitude? We expect that:(1) species distributed in cold regions are specialized for low-temperature environments(i.e. narrow niche breadth center around low temperatures);(2) a negative relationship between species niche breadth on temperature and precipitation axes according to the tradeoff hypothesis(i.e. species that tolerate a broad range of precipitation regimes cannot also tolerate a broad range of temperatures);(3) precipitation niche breadth decreases with altitude or latitude, whereas temperature climatic niche breadth increases with altitude or latitude. Based on the analytical results we found that:(1) temperature niche breadth and position are negatively related, while precipitation niche breadth and position are positively related;(2) there is no trade-off between temperature and precipitation niche breadths; and (3) temperature niche breadth and latitude/altitude are positively related, but precipitation niche breadth and latitude/altitude are not significantly related. Our results show many similarities with previous studies on climatic niche widths reported for amphibians and lizards, which provide further evidence that such macroecological patterns of variation in climatic niche breadths may be widespread.

The Mitochondrial Genome of Pseudocalotes microlepis (Squamata: Agamidae) and its Phylogenetic Position in Agamids

We describe the complete mitochondrial genome of a small-scaled forest agamid （Pseudocalotes microlepis）, which is 17 873 bp in size, containing 13 PCGs, 2 rRNAs, 22 tRNAs and non-coding regions. The mitogenome has a typical gene order among squamates. 13 PCGs include 2 start codons （ATG and ATA）, 3 stop codons （TAG, TAA and AGG）, and an incomplete stop codon （T-）. Codon usage analyses showed that CUA-Leul and CGG-Arg are the most frequently and rarely used codon, respectively. All 22 tRNAs were predicted to form canonical cloverleaf secondary structures, except for two tRNAs （tRNAcys and tRNASer （AGY）） lacking the dihydorouridine （DHU） arm. The large non- coding region （control region） is 2 687 bp long （28.3% T, 18.2% C, 42.3% A, and 11.2% G）, with four different types of repeating sequences. The phylogenetic tree resulting from BEAST analyses based on concatenated 2 rRNAs and 13 PCGs in sequence revealed that the newly sequenced P. microlepis, where the genus Acanthosaura were aggregated. Together with Calotes versicolor, they constitute the subfamily Draconinae.

Lineage diversification and niche evolution in the Reeves’Butterfly Lizard Leiolepis reevesii(Agamidae)

We used mitochondrial cytochrome b and ND4 genes and 9 microsatellite loci to determine genetic diversity,population structure,evolutionary history,and migration patterns within the Reeves’butterfly lizard Leiolepis reevesii(Agamidae).Considering molecular-based phylogeographical lineages,we then performed niche equivalency and similarity tests between divergent lineages.Phylogenetic analyses based on mitochondrial DNA(mtDNA)data revealed 2 lineages(A and B)diverging≈0.84 million years ago and,respectively,restricted to the northern and southern portions of the Wuzhishan and Yinggeling mountain ranges.Lineage B contains individuals from southern Hainan;Lineage A includes individuals from all other localities and can be further divided into 3 clusters according to microsatellite data.The null hypothesis that the 2 lineages shared identical niches was rejected in all niche equivalency tests,indicating niche shifts during genetic divergence.Similarity tests provided evidence of niche conservatism,suggesting that the 2 lineages share more characteristics of their niche spaces than randomly expected.The niche similarity and equivalency tests indicated a complex niche pattern in which both lineages share a main portion of their ecological spaces.The climatic niche of Lineage B represented a marginal and specialized fraction of the entire ecological space of the climatic niche of Lineage A,with warmer conditions.Isolation caused by orogenesis and subsequent niche divergence,together with local adaptation,may have led to genetic differentiation and further lineage sorting in L.reevesii.