The genera Melyvonnea gen. nov. and Mesophyllum s.s. (Melobesioideae, Corallinales, Rhodophyta) particularly from the central Atlantic Ocean. (22nd May 2014)

• Record Type: Journal Article
• Authors: Athanasiadis, Athanasios; Ballantine, David L.
• Is Part Of: Nordic journal of botany. Volume 32:Number 4(2014:Aug.)
• Page Start: 385
• Page End: 436
• Publication Date: 2014-05-22
• Subjects: Botany -- Periodicals; Mycology -- Periodicals; 580
• DOI: 10.1111/njb.00265
• Languages: English
• ISSNs: 0107-055X

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>We propose the new genus <italic>Melyvonnea</italic> to accommodate species previously included in <italic>Mesophyllum</italic> having: a) perithallial protuberances that may branch and dominate over the encrusting base, b) monoecious gametophytes with gametangial conceptacles occasionally developed in superimposition, c) spheroid carposporangial chambers (lacking a central pedestal), and d) filaments lining canals of multiporate roofs composed of 3 to 5 cells with distinctively elongate basal cells. The new genus shares with <italic>Mesophyllum</italic> the development of a predominantly coaxial hypothallium. <italic>Melyvonnea</italic> presently accommodates three species in the Central Atlantic, viz. the generitype <italic>Melyvonnea canariensis</italic> (Foslie) comb. nov. from the Canary Islands, <italic>Melyvonnea erubescens</italic> (Foslie) comb. nov. ( = <italic>Mesophyllum incertum;</italic> type locality: Bermuda) from the western Atlantic, <italic>Melyvonnea aemulans</italic> (Foslie & Howe) comb. nov. from Puerto Rico, and one Indo‐Pacific species, <italic>Melyvonnea madagascariensis</italic> (Foslie) comb. nov. We also emend <italic>Mesophyllum</italic> Lemoine to encompass Northern Hemisphere species that lack the above apomorphies of <italic>Melyvonnea</italic> and in addition develop a central pedestal in carposporangial conceptacles (via dissolution of the surrounding cells) with gonimoblasts bending down to fill the empty space. <italic>Mesophyllum</italic> sensu stricto currently includes six species in the northeast Pacific (<italic>M. aleuticum, M. conchatum, M. crassiusculum, M. lamellatum, M. megagastri, M. vancouveriense</italic>), two species in the western Atlantic (<italic>M. mesomorphum</italic> and <italic>M. syntrophicum</italic>), and three species in the northeast Atlantic and the Mediterranean Sea (<italic>M. expansum, M. lichenoides, M. philippii</italic>). Gametophytic species of each genus show a mainly disjunct distribution being restricted to the tropics–subtropics (<italic>Melyvonnea</italic>) and the temperate waters of the Northern Hemisphere <italic>(Mesophyllum</italic> s.s.). This classification is supported by a consensus of studies of all well‐known species of <italic>Mesophyllum</italic> sensu Adey (1970), and is based on a phylogenetic analysis of morphological and anatomical characters in addition to molecular evidence.</p> </abstract>