Morphological and reproductive evidence for a new circumscription of the genus Trematocarpus (Rhodophyta, Sarcodiaceae)
Article Sidebar
Main Article Content
Abstract
An updated circumscription is proposed for the genus Trematocarpus, including new data based on morphological and reproductive studies of the type species Trematocarpus dichotomus. The material studied included T. dichotomus, T. acicularis and T. concinnus from Peru, Chile, New Zealand and Australia. Bibliographic information on T. pygmaeus, T. fragilis, T. flabellatus, T. papenfussi and T. affinis is also given. The initial diagnosis permitted the inclusion solely of species having cylindrical thalli, height no greater than 5 cm, zoned tetrasporangia and protruding cystocarps, and was based on descriptions of individuals of T. dichotomus and T. virgatus. The latter species, mis-identified, proved to be Sarcodiotheca gaudichaudii, and thus the description of the genus was based on characteristics of two species from two different genera, later partially clarified by Schmitz (1989) who lectotypified the genus based on the characteristics of T. dichotomus from Peru. The present study completes and corrects the original diagnosis, extending maximum sizes to 30 cm, thalli cylindrical, subcylindrical or flattened in crosssection, localized origin of gametic and sporific reproductive organs on the concave or convex surface in flattened thalli, and over the entire surface of cylindrical or subcylindrical thalli, and adhesion by a disc with or without stoloniferous projections. New information is presented on the appearance and development of the carpogonial branch from a differentiated intercalar cell in the cortex, which develops a carpogonial filament of three or four cells through successive divisions. Processes of post-fertilization show procarpial fusion, fusion of gonimoblastic cells and external generation of cystocarps. It is also noted that the species are dioic. This description sets apart the genera Sarcodiotheca, Agardhiella and Eucheuma, which have morphological and reproductive characteristics similar to Trematocarpus, and correctly incorporates the eight currently recognized species of the genus.
Downloads
Article Details
This work is licensed under a Creative Commons Attribution 4.0 International License.
This is an open access article distributed under a Creative Commons Attribution 4.0 License, which allows you to share and adapt the work, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Figures, tables and other elements in the article are included in the article’s CC BY 4.0 license, unless otherwise indicated. The journal title is protected by copyrights and not subject to this license. Full license deed can be viewed here.