Bibliographic Detail
Hughey, J.R. & Hommersand, M.H., 2008
Reference:
Hughey, J.R. & Hommersand, M.H. (2008). Morphological and molecular systematic study of Chondracanthus (Gigartinaceae, Rhodophyta) from Pacific North America. Phycologia 47: 124-155.
Abstract:
Species boundaries in the Gigartinaceae are poorly defined due to the high degree of phenotypic plasticity exhibited by
the thallus, with the result that many superfluous taxa have been described. To clarify the taxonomy of species of
Chondracanthus Ku¨ tzing reported from the Gulf of California and Pacific coast of North America, morphological and
molecular phylogenetic studies were performed. Phylogenetic analyses of chloroplast and nuclear DNA yielded nearly
congruent hypotheses. DNA from type material was examined from select species to validate the correspondence
between modern and historically important collections. Monographic observations on species from Pacific North
America were included to clarify species boundaries. Analyses identified two species from the Gulf of California and
nine from the Pacific coast. The following statements are supported: (1) Gigartina serrata Gardner is independent of
Chondracanthus canaliculatus (Harvey) Guiry, and Chondracanthus serratus (Gardner) comb. nov. is being proposed. (2)
Thalli genetically close to C. canaliculatus but morphologically similar to G. serrata represent a new species of
Chondracanthus from Pacific Baja California, Mexico, Chondracanthus bajacalifornicus sp. nov. (3) Pinnate thalli
previously referred to C. canaliculatus but larger and closely related to C. canaliculatus and C. bajacalifornicus represent
a new species of Chondracanthus from southern California, Chondracanthus kjeldsenii sp. nov. (4) Gigartina californica J.
Agardh is conspecific with C. corymbiferus (Kützing) Guiry. (5) Gigartina boryi Setchell & Gardner is a heterotypic
synonym of C. harveyanus (Kützing) Guiry. (6) Chondracanthus spinosus (Ku¨ tzing) Guiry is a polymorphic species that
includes G. armata J. Agardh, G. asperifolia J. Agardh, G. echinata Gardner, G. eatoniana J. Agardh, and G. farlowiana
J. Agardh. (7) Chondracanthus exasperatus (Harvey & Bailey) Hughey encompasses a range of forms of varying size,
margin shape, pigmentation, and thickness. (8) Gigartina acicularis sensu Dawson from the Gulf of California, C.
johnstonii (Dawson) Guiry, C. macdougalii (Dawson) Guiry, and G. pectinata Dawson are conspecific with C.
squarrulosus (Setchell & Gardner) Hughey, P. C. Silva & Hommersand. (9) Chondracanthus intermedius is tentatively
confirmed in the Gulf of California.
