Revisiting the systematics of Ganonema (Liagoraceae, Rhodophyta) with emphasis on species from the northwest Pacific Ocean

Abstract

The genus Ganonema was distinguished from the other genera in the Liagoraceae morphologically by several reproductive and vegetative features, including spermatangia formed in dense, dendroidal clusters; carpogonial branches remaining unfused after fertilisation, having compact gonimoblasts; and medullary filaments being relatively broad. In addition, the generitype G. farinosum was uniquely characterised by its carpogonial branches being borne on small, specialised branches arising from the basal part of assimilatory filaments, a feature not seen in other species of Ganonema. Our molecular analyses, incorporating several species currently attributed to Ganonema, showed that the genus was polyphyletic and represented in three independent lineages, one including the generitype G. farinosum, a second including 'G' dendroideum, and a third containing three 'Ganonema' ÇG.' clavatum, 'G.' borowitzkae and 'G.' samaense) from the northwest Pacific Ocean. We have therefore proposed two segregate genera, Gloiocallis gen. nov. for 'G.' dendroideum and Hommersandiophycus gen. nov. for 'G. ' clavatum, 'G.' borowitzkae and 'G.' samaense. Morphologically, Gloiocallis differed from Ganonema and Hommersandiophycus in having only a few involucral filaments produced from the cortical cells above the supporting cell and most cells of the gonimoblasts differentiating into carposporangia, Hommersandiophycus can be separated from related genera by a combination of unfused carpogonial branches, involucral filaments produced from the cortical cells above and below the supporting cell and its neighbouring cells, carposporangia differentiating sequentially in chains of two to three and gonimoblasts being hemispherical to spherical! The taxonomy of other species currently placed in Ganonema but not analysed in this study requires further work.

A phylogenetic re‐appraisal of the family Liagoraceae sensu lato (Nemaliales, Rhodophyta) based on sequence analyses of two plastid genes and postfertilization development

“…(), as well as 36 rbc L sequences of the Liagoraceae previously published by Lin et al. (,b, ). The analyzed data matrix included 1,383 base pairs (bp) for rbc L with 517 parsimony‐informative sites and 1,932 bp for psa A with 796 parsimony‐informative sites.…”

“…Genera in Clade I (the Liagoraceae sensu stricto as defined herein) have the widest geographic distribution, occurring from temperate northern Atlantic and southern Pacific Oceans through warm‐water regions of the Indo‐Pacific and Caribbean Sea (Abbott and Hollenberg , Huisman , Lin et al. , , ). By contrast, Yamadaella (Clade II) and Liagoropsis (Clade IV) are restricted to warm‐water regions of the Indo‐Pacific and western Atlantic Oceans (Yamada , Doty and Abbott , Abbott ), whereas Nemalion (Clade III) is found only in temperate regions but is widespread in both hemispheres (Womersley , p. 81, Guiry and Guiry , see Le Gall and Saunders ).…”

“…DNA materials were extracted either from newly collected specimens dried in silica gel or from the DNA collections of the Liagoraceae deposited at the Seaweed Laboratory, NTOU, Taiwan, as used in Lin et al. (,b, , ). DNA samples were prepared using the DNeasy Plant Mini Kit (Qiagen, Valencia, CA, USA) following the instructions of the manufacturer.…”

“…New sequence data and those available from GenBank (Lin et al. ,b, , for some Liagoraceae, Wang et al. for some Galaxauraceae, Müller et al.…”

Molecular Assisted Identification Reveals Hidden Red Algae Diversity from the Burica Peninsula, Pacific Panama

“…Lin et al [41] established Hommersandiophycus for G. borowitzkae and two other Ganonema species after molecular and morphological analyses resolved these species in a distinct clade with a number of synapomorphic characters states for carpogonial branches and carposporophytes. The examined PHYKOS-4618 specimen was male and matched the description of spermatangia initials being cut off from subapical cells and developing in clusters [41] ( Figure 6A,B). The species was known only from East Asia (Taiwan, The Philippines) and Western Australia, and this is the first report from the Eastern Pacific.…”