Integrative taxonomy at the nexus of population divergence and speciation in insular speckled rattlesnakes

ABSTRACT

We describe two diminutive species of rattlesnakes (genus Crotalus) from small nearshore islands off the coast of Baja California in the western Gulf of California, Mexico. In order to test the hypothesis that some island populations represent cohesive species entities, we applied linear discriminant analysis and uniform validation procedures to multiple classes of intrinsic trait data. By using previously recognised species to establish a threshold for species recognition, we found that assignment of specimens to either new species was as probable as with other established rattlesnake species within the speckled rattlesnake (Crotalus mitchellii) complex. We also found that assignment of specimens from other island populations was not as probable as for the established species, and these populations are referable to C. pyrrhus. The species endemic to Piojo Island is most closely related to other island and mainland populations of C. pyrrhus whereas the species endemic to Cabeza de Caballo Island is apparently most closely related to C. angelensis, a nearby island endemic of large body size. However, patterns from both mitochondrial and nuclear phylogenies, and phenotypic variation, indicate that evolutionary trajectories of both of these species have been influenced by introgression from C. angelensis. We speculate that collective evidence based on contrasting patterns of nuclear and mitochondrial evolution supports a hybrid origin of the species from Cabeza de Caballo Island followed by exceptionally rapid mitochondrial evolution. Consistent with small body size, both species show a reduction in various scale counts relative to other species of the C. mitchellii species complex, suggesting that dwarfism is not simply a plastic response to insular conditions.

http://www.zoobank.org/urn.lsid:zoobank.org:pub:FBC8A11B-04A3-4231-85CA-3972DF5A42FF     

A comparative study of the mating call of Pelophylax ridibundus and Pelophylax kurtmuelleri (Anura: Ranidae) from syntopic and allotopic populations

The mating call of Pelophylax ridibundus and Pelophylax kurtmuelleri from three syntopic and five allotopic populations was studied. All recordings were made during the mating season. We tested the hypothesis that the call of P. ridibundus from allotopic populations would differ from that in syntopic populations with P. kurtmuelleri. For the comparative analysis we used univariate and multivariate statistical methods and the following characteristics: call duration, pulse group duration, pulse group interval, pulse group period, pulse group number, minimum, maximum, fundamental and dominant frequencies and pulse energy. Analyses reveal a trait divergence in most of the studied characteristics of the signals, with stronger differentiation between P. kurtmuelleri and P. ridibundus in syntopic populations than between the two species in allotopic ones. The possible evolutionary implications of this divergence are discussed.     

Redox condition during Ediacaran–Cambrian transition in the Lower Yangtze deep water basin,South China: constraints from iron speciation and δ~(13) Corg in the Diben section,Zhejiang

Cherts of the Piyuancun Formation and black mudstones of the Hetang Formation in Diben Town, Kaihua County, Zhejiang were deposited in a deep water basin of the Lower Yangtze area during the Ediacaran–Cambrian transition(E–C transition), offering an opportunity to reconstruct the ancient redox condition of the deep water basin. Total 53 samples were collected and analyzed for iron speciation, including pyrite iron(FePy), carbonate associated iron(FeCarb), iron oxide and hydroxide(FeOx),magnetite iron(FeMag) and total iron(FeT) as well as d13 Corgto gain a deeper understanding of specific redox condition during the period. The results show that(1) most samples have pyrite concentration \1 %, with the FePy/FeHR ratio ranging from \0.01 to 0.81(mostly \0.5), and the FeHR/FeT ratio between 0.39 and 0.93(mostly [0.5).(2) The E–C boundary in the Diben section occurred at the maximum negative excursion of organic carbon isotope within the Piyuancun Formation, which can be correlated with other sections by using d13 Corg. We thus concluded that the relatively high content of highly reactive iron and low content of pyrite iron in the Diben section indicate a minor occurrence of H2 S and a predominance of anoxic and ferruginous environment, which is similar to other reported sections such as the Longbizui and Yanwutan sections, western Hunan. In addition, oxygen concentration in sea water showed an increasing trend in the interval corresponding to the bottom and upper layer of the Hetang Formation as indicated by the FeHR/FeT ratio, which decreased from 0.7 to 0.38, however, it was not great enough to oxidize the whole deep water. Therefore, during the E–C transition deep water basin in South China was most likely an anoxic and ferruginous enrironment, which prevented metazoon from the evolution in the deep water basin. Our work offers an important reference to better understanding of the spatiotemporal occurrence and dynamic processes of the ‘‘Cambrian Explosion'.     

獐子岛附近海域沉积物中氮和磷的分布来源及污染风险评价

【目的】为探讨北黄海獐子岛附近海域氮、磷的来源及其污染风险状况,对该海域表层沉积物中氮、磷的形态和分布特征进行分析。【方法】采用K2S2O8氧化法和HCl浸取法对獐子岛附近海域13个站位的表层沉积物中总氮(TN)、总磷(TP)及其无机和有机态的含量进行分析,并采用单因子标准指数法对氮、磷的污染水平进行评价。【结果】獐子岛附近海域沉积物中TN和TP的含量分别为0.192~1.357 mg/g和0.302~0.489mg/g,有机氮(ON)和无机磷(IP)是表层沉积物中氮和磷的主要存在形式,分别占TN与TP的90.93%和82.84%。沉积物中TN和TP在研究区域南部含量较高,这与沉积物粒度密切相关;而ON、有机磷(OP)两者都与有机碳(TOC)含量具有显著相关性,说明它们具有相似的来源。单因子标准指数法分析表明獐子岛附近海域沉积物中TP含量较低,标准指数均小于1;而TN含量相对较高,其标准指数为0.35~2.47。【结论】獐子岛附近海域沉积物中氮为陆源和自生混合来源,而磷主要是陆源输入;海域沉积物环境受到氮的污染。     

Microstructures and nanostructures of high Andean Penaincisalia lycaenid butterfly scales (Lepidoptera: Lycaenidae): descriptions and interpretations

The scales of one high Andean eumaeine lycaenid butterfly species with pale dorsal coloration and four species with vivid dorsal colour were investigated using field emission scanning electron microscopy. The micro‐ and nanostructures are illustrated, described, measured, and interpreted. The vivid colours in the species are caused by a pepper‐pot nanostructure of Urania‐type scales. This nanostructure is a three‐dimensional lattice within the body of the individual scale. The scales of the non‐vivid orange species are lacking this nanostructure and the surfaces of their scales show high microstructure irregularities. This absence of vivid colour may be correlated with thermal regulation. The irregularity of the scale microstructures suggests a heavy environmental pressure on the populations sampled. Previously unknown structural variations of Urania‐type scales are also described. The existence of closed scale microcell structures, explained as an apomorphic character in the tribe Eumaeini, most probably evolved independently several times. It is hypothesized that scale micro‐ and nanostructure modifications develop syntopically within a population, which in turn can lead to rapid diversification.     

Genetic diversity in the Carabodes marginatus species group (Acarida,Oribatida, Carabodidae) as inferred from allozymes

Ten populations representing four species of the ‘Carabodes marginatus’ group, as C. marginatus, C. affinis, C. quadrangulus and C. montanus from central Italy have been studied for genetic variation at 16 enzymatic loci by electrophoresis. Morphotypes close to C. marginatus but easily distinguishable by the shorter marginal notogastral setae were also included in the analysis to evaluate their systematic status. Carabodes arduinii, a very different species from the ‘coriaceus’ group, was employed as an out-group. Phylogenetic relationships among different species were studied and inferred data demonstrated that cladogenetic events occurred, even though rates of molecular and morphological evolution do not correlate. Morphotypes related to C. marginatus were genetically very close to the type specimens, but a different pattern of allele frequency was observed in sympatric populations of the two setal forms. Possible explanations for this finding are suggested in relation to historical processes. The rate of gene flow among populations of the two morphs was estimated by both Wright's F _st and Slatkin's Nm methods. These two different procedures yielded contradictory results.     

腐殖土对活性污泥中重金属形态分布的影响

分别投加0,0.5,1,2,3和5g腐殖土(HS)于1000mL活性污泥中充分搅拌20d,采用Tessier五步提取法对其中锌、镍、铜、铅元素的形态分布进行分析研究,结果表明,投加腐殖土能明显改变活性污泥中重金属的形态分布.对锌元素,可交换离子态(F1)锌,碳酸盐结合态(F2)锌和铁锰氧化物结合态(F3)锌含量与HS投加量有显著负相关性(0.9266,0.9310,0.9144,置信度P0.01),硫化物及有机结合态(F4)含量与HS的投加量有显著的正相关性(0.9304,P0.01);对镍元素,F1镍和F2镍含量与HS的投加量具有显著的负相关性(0.9027,0.9724,P0.01),F4镍和残渣态(F5)镍含量与HS的投加量具有显著的正相关性(0.9188,0.9123,P0.01);对铜元素,F2铜含量与HS的投加量呈负相关性(0.7145,P0.05);对铅元素,F3铅和F4铅含量与HS投加量具有负相关性(0.7027,0.7635,P0.05),F5铅含量与HS投加量具有正相关性(0.7668,P0.05).投加腐殖土能明显降低活性污泥中锌,镍元素的潜在迁移能力.     

化学浸提法研究中药党参中活性铝的溶出及形态分布

利用KCl,NH4Ac,HCl,NaOH 4种浸提液将中药党参中存在的铝浸提溶出,得到党参中铝的不同形态,采用铬天青S(CAS)分光光度法进行定量测定,得到中药党参中活性铝的形态分布,并对影响铝溶出的若干因子进行了探讨.浸提液中铝的回收率为97.0%～109.3%.     

中草药中微量元素形态分析研究进展

综述了中草药中微量元素形态分析的内容以及元素形态的提取、分离与测定.引用文献34篇.     

论多细胞物种的进化机制

本文对生命史中多细胞物种的形成机制提出了创新性的观点并对此进行论述。该新观点认为:生命进化的本质是各种生命生存效率优化的过程。在此过程中,多细胞物种的产生必然要解决一对矛盾,即单细胞局部利益最大化与多细胞整体利益之间的矛盾。解决这对矛盾是保证多细胞整体生存竞争效率的前提。因此,多细胞物种的进化必然是不断优化整体调控机制过程。调控机制的建立与完善是通过细胞的智能活动完成的。文章对多细胞物种的成种过程进行了逻辑推理,并依此推理过程提出了6个重要的预测,通过列举与这些预测相一致的事实证据来说明笔者该观点的合理性。