A proposal to resurrect the tribe Monosporeae Schmitz et Hauptfleisch, with a description of Tanakaella itonoi sp. nov. (Ceramiaceae, Rhodophyta) from southern and western Australia

Phylogenetic relationships among 69 species of the Ceramiales (51 Ceramiaceae, six Dasyaceae, seven Delesseriaceae, and five Rhodomelaceae) were determined based on nuclear SSU rDNA sequence data. We resolved five strongly supported but divergent lineages among the included Ceramiaceae: (i) the genus Inkyuleea, which weakly joins other orders of the Rhodymeniophycidae rather than the Ceramiales in our analyses; (ii) the tribe Spyridieae, which is sister to the remainder of the included ceramialean taxa; (iii) the subfamily Ceramioideae, weakly including the tribe Warrenieae; (iv) the subfamily Callithamnioideae; and (v) the subfamily Compsothamnioideae, which emerges as sister to the Dasyaceae/Delesseriaceae/Rhodomelaceae complex, thus rendering the Ceramiaceae sensu lato unequivocally paraphyletic, as has been argued separately on anatomical grounds by Kylin and Hommersand. Our data support a restricted concept of the Ceramiaceae that includes only one of the five lineages (Ceramioideae) that we have resolved. In addition to failing to ally with the Ceramiales in our molecular analyses, species of Inkyuleea differ substantially from other Ceramiaceae sensu lato in details of pre- and postfertilization development. The genus Inkyuleea is here assigned to the Inkyuleeaceae fam. nov., which we provisionally retain in the Ceramiales. Species of Spyridia also differ from the remaining Ceramiaceae in their postfertilization development, and, in light of our molecular data, the genus Spyridia is assigned to the Spyridiaceae. The Callithamnioideae is strongly monophyletic (100% in all analyses), which, in combination with key anatomical differences, supports elevation to family status for this lineage as the Callithamniaceae. Similarly, the Compsothamnioideae is solidly monophyletic in our molecular trees and has a unique suite of defining anatomical characters that supports family status for a complex that we consider to include the tribes Compsothamnieae, Dasyphileae, Griffithsieae, Monosporeae, Ptiloteae, Spermothamnieae, Sphondylothamnieae, Spongoclonieae, and Wrangelieae, for which the reinstated family name Wrangeliaceae is available.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

PHYLOGENETIC RELATIONSHIPS AMONG LINEAGES OF THE CERAMIACEAE (CERAMIALES, RHODOPHYTA) BASED ON NUCLEAR SMALL SUBUNIT rDNA SEQUENCE DATA¹

Choi¹,

Kraft²,

Kim³

et al. 2008

“…The third type contains the haploid nucleus of the auxiliary cell but which is cut off completely and terminally from the proximal pole of the latter. This type was named a “disposal” cell by Huisman and Kraft (1992) when they introduced the genus Guiryella , a representative of the Monosporeae (Huisman and Gordon‐Mills 1994). Such cells had been previously observed in some tribes of the subfamily Compsothamnioideae as defined by Itono (1977) (e.g.…”

Section: Discussionmentioning

confidence: 99%

MORPHOLOGY AND SYSTEMATICS OFSCIUROTHAMNION STEGENGAEGEN. ET SP. NOV. (CERAMIACEAE, RHODOPHYTA) FROM THE INDO‐PACIFIC¹

Clerck¹,

Kraft²,

Coppejans³

2002

A new ceramiaceous alga, Sciurothamnion stegengae De Clerck et Kraft, gen. et sp. nov., is described from the western Indian Ocean and the Philippines. Sciurothamnion appears related to the tribe Callithamnieae on the basis of the position and composition of its procarps and by the majority of post‐fertilization events. It differs, however, from all current members of the tribe by the presence of two periaxial cells bearing determinate laterals per axial cell. Additionally, unlike any present representative of the subfamily Callithamnioideae, no intercalary foot cell is formed after diploidization of the paired auxiliary cells. The genus is characterized by a terminal foot cell (“disposal cell”), which segregates the haploid nuclei of the diploidized auxiliary cell from the diploid zygote nucleus. The nature of three types of foot cells reported in the Ceramiaceae (intercalary foot cells containing only haploid nuclei, intercalary foot cells containing haploid nuclei and a diploid nucleus, and terminal foot cells containing only haploid nuclei) is discussed.

“…Phylogenetic implications for the independent derivation of Rhodocallis are further reinforced by a consideration of reproductive characters. Procarp composition and position are thought to be conservative features that usefully define subfamilies and tribes in the Ceramiaceae (Hommersand 1963, Huisman and Gordon-Mills 1994, Athanasiadis 1996 and have received heavy emphasis in phylogenetic speculations about the family. The ancestral procarp is generally thought to have been one in which carpogonial branches were produced in succession along the distal lengths of indeterminate axes, with the basal cell of a determinate lateral serving as the supporting cell that bore a single sterilecell group (remnant of the fertile determinate lateral) in addition to the carpogonial branch.…”

Section: Discussionmentioning

confidence: 99%

MORPHOLOGY AND SYSTEMATICS OF RHODOCALLIS ELEGANS, RHODOCALLIDEAE, TRIB. NOV. (CERAMIACEAE, RHODOPHYTA), FROM SOUTHEASTERN AUSTRALIA

Hommersand

Wilson

Kraft

1998

Recent collections of Rhodocallis elegans Kützing from southeastern Australia have permitted detailed observations of vegetative and reproductive structures that reveal features not exhibited by any existing tribe of Ceramiaceae. As a consequence, we establish the new tribe Rhodocallideae based on the unispecific genus Rhodocallis. Defining characters include: 1) four periaxial cells cut off in an alternating (rhodomelaceous) sequence; 2) determinate branchlets of two types: a) persistent lateral branchlets produced from the first‐formed periaxial cells, and b) deciduous transverse branchlets produced from the second and third periaxial cells, with cortical filaments issuing from all four periaxial cells; 3) first‐ and second‐order determinate branchlets terminated by thick‐walled spines; 4) indeterminate branches formed at the tips of directly converted determinate branchlets; 5) axial cells of indeterminate branches heavily corticated by a cylinder of descending rhizoidal filaments; 6) spermatangial parent cells borne directly on unmodified outer cortical cells; 7) carpogonial branches borne in series on second and third periaxial cells of modified indeterminate axes; 8) procarps lacking sterile‐cell groups; 9) a single derivative of the zygote nucleus transferred from the carpogonium to the auxiliary cell directly through a tube rather than by means of a connecting cell; 10) gonimoblasts surrounded by a network of rhizoidal filaments through which the gonimolobes protrude, the carposporophyte subtended by an investment of determinate branchlets; and 11) tetrasporangia tetrahedrally divided, borne on surface cortical cells of special determinate branchlets and protruding outside the cuticular layer.