Hind Katharine R, Gabrielson Paul W, Jensen Cassandra, Martone Patrick T
Department of Botany and Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z4.
Hakai Institute, Pruth Harbour, Calvert Island, British Columbia, V0P 1H0, Canada.
J Phycol. 2018 Dec;54(6):788-798. doi: 10.1111/jpy.12788. Epub 2018 Oct 16.
This is the first report of a coralline genus with both geniculate (upright fronds with non-calcified joints) and nongeniculate species that has been verified by DNA sequence data. Two nongeniculate (crustose) species of Bossiella are recognized, B. mayae sp. nov. and B. exarticulata sp. nov. DNA sequencing of the lectotype specimen of Pseudolithophyllum whidbeyense revealed that this name had been misapplied and instead belongs to an undescribed coralline species in the Hapalidiales. Phylogenetic analyses of concatenated DNA sequences (psbA, rbcL, COI-5P) indicate that B. mayae and B. exarticulata represent phenotypic reversals from the geniculate character state back to the nongeniculate character state. Secondary loss of genicula has occurred three times in the subfamily Corallinoideae, once to generate the entirely nongeniculate genus Crusticorallina and twice in the now morphologically heterotypic Bossiella. Since phenotypic reversals have occurred several times during the evolution of coralline algae, we speculate about the putative mechanism and adaptive significance of this phenomenon.
这是关于一个珊瑚藻属的首次报告，该属包含有节（具直立叶状体且有非钙化关节）和无节种类，且已通过DNA序列数据得到验证。确认了博氏藻属的两个无节（壳状）种类，即新物种马氏博氏藻和新物种离节博氏藻。对惠德比拟石叶藻模式标本的DNA测序表明，该名称被误用，实际上属于海膜目一个未描述的珊瑚藻物种。对串联DNA序列（psbA、rbcL、COI-5P）的系统发育分析表明，马氏博氏藻和离节博氏藻代表了从有节性状状态到无节性状状态的表型逆转。在珊瑚藻亚科中，关节的二次丢失发生了三次，一次产生了完全无节的硬壳珊瑚藻属，两次发生在现在形态异型的博氏藻属中。由于表型逆转在珊瑚藻的进化过程中发生了几次，我们推测了这一现象的假定机制和适应性意义。
