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T ylotus laqueatus , a new species of D icranemataceae ( G igartinales, R hodophyta) from the H awaiian I slands
Author(s) -
Kraft Gerald T.,
Conklin Kimberly Y.,
Sherwood Alison R.
Publication year - 2014
Publication title -
phycological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.438
H-Index - 44
eISSN - 1440-1835
pISSN - 1322-0829
DOI - 10.1111/pre.12030
Subject(s) - thallus , frond , biology , bryopsida , gametophyte , botany , stipe (mycology) , type locality , genus , anatomy , moss , pollen
Summary A rarely collected shallow‐subtidal H awaiian macroalga has been determined anatomically and molecularly to belong to an undescribed species of T ylotus J . A gardh, the most widely distributed genus of the small, mostly Australian‐endemic family D icranemataceae. Thalli are repent and imbricate on calcareous boulders at the type locality on O ‘ahu, and are anchored both basally and by haptera arising marginally and ventrally on the (sub‐)dichotomous, linear axes. Simple or forked terete haptera can be a means of perennation by the occasional direct issuing of adventitious blades. Fronds are multiaxial and consist of a broad pseudoparenchymatous medulla of thick‐walled cells surrounded on both sides by a two‐ or three‐layered small‐celled pigmented cortex in which numbers of ‘glandular’ hairs are embedded. Tetrasporangia are zonate, and gametophytes are monoecious. Carpogonial branches are three‐celled, directed to the thallus surface, and borne laterally on inner‐cortical supporting cells; cystocarps are prominently protuberant and scattered sparingly on dorsal frond surfaces, the carposporophytes directed outwardly beneath an ostiolate pericarp and connected to the parent gametophyte across a broad placental base in which the remnant auxiliary cell persists centrally. The inner surface of the pericarp is unusual in producing extensive patches or isolated islands of short gonimoblast filaments with terminal carposporangia as an apparent result of the implantation of gonimoblasts into the tissue of the lining. Anatomy indicates that the new species is more closely related to the E ast‐ A sian T ylotus lichenoides O kamura than to the only other described member of the genus, the type species T . obtusatus ( S onder) J . A gardh from southern A ustralia. An rbc L phylogeny supports placement of sequences for Hawaiian specimens within the genus T ylotus but distinct from all previously recorded sequences of T ylotus . As is widely reported in other molecular‐phylogenetic analyses of the G igartinales, we find that support for generic and familial relationships within the order is strong whereas that for between‐family relationships is low.