Species Diversity of Shallow Water Zoanthids (Cnidaria: Anthozoa: Hexacorallia) in Florida

Shallow water zooxanthellate zoanthids are a common component of the coral reef ecosystems of the Caribbean. Despite this, their species diversity remains poorly understood. In this study, collected Palythoa, Zoanthus, Isaurus, and Terrazoanthus specimens from the waters of Florida were phylogenetically examined to obtain a better understanding of zoanthid species diversity in the Caribbean. Surprisingly, the results from analyses utilizing three DNA markers (mitochondrial 16S ribosomal DNA, cytochrome oxidase subunit I, and the internal transcribed spacer of ribosomal DNA) showed the presence of at least eleven species, of which up to four appear undescribed. Additionally, the presence of the genus Terrazoanthus in the Caribbean was confirmed for the first time. Attempts to match phylogenetic species or clades with original literature were hampered by vague and short original descriptions, and it is clear that for Atlantic Palythoa and Zoanthus species an in-depth and multidisciplinary investigation is needed to reconcile recent phylogenetic results such as in this study with traditional taxonomy. Furthermore, most shallow water zoanthid species from Florida were observed to have close, sister-species relationships with previously investigated species in the Pacific Ocean. These results indicate that many brachycnemic zoanthid species likely had a Caribbean-Pacific distribution until the formation of the Isthmus of Panama. However, due to inadvertent redescriptions, overall species diversity in these two common genera is likely much lower than literature indicates

Ascension Island shallow-water Zoantharia (Hexacorallia: Cnidaria) and their zooxanthellae (Symbiodinium)

This is the first report on the Zoantharia fauna (Cnidaria: Hexacorallia) of the isolated oceanic island of Ascension, southern Atlantic, where zoantharians are a dominant component of the shallow-water benthos. Specimens from two expeditions (1983, 2012) were examined regarding external morphology and molecular phylogeny using three DNA markers, which confirmed the presence of four zoantharian species: Palythoa caribaeorum; Palythoa aff. clavata; Parazoanthus swiftii; and Zoanthus sp. Two of these, Palythoa aff. clavata and Parazoanthus swiftii, were previously only known from the western Atlantic and Caribbean. Molecular examination of the zooxanthellae (=Symbiodinium spp.) of Palythoa specimens showed that they were in association with only one type, subclade C1.Darwin Initiative [EIDCF012]; Japan Society for the Promotion of Science [217700896]; University of the Ryukyus; Temminck Fellowshipinfo:eu-repo/semantics/publishedVersio

Descriptions of two azooxanthellate Palythoa species (Subclass Hexacorallia, Order Zoantharia) from the Ryukyu Archipelago, southern Japan

Two new species of zoantharians (Hexacorallia, Zoantharia, Sphenopidae), Palythoa mizigama sp. n. and P. umbrosa sp. n., are described from the Ryukyu Archipelago, southern Japan. Unlike almost all other known Palythoa spp., both species are azooxanthellate and inhabit low-light environments such as floors or sides of caves, crevasses, or hollows of shallow coral reefs. The two species were initially considered to be the same species from their similar habitat environments and highly similar morphological features. However, phylogenetic analyses of nuclear internal transcribed spacer (ITS) ribosomal DNA, mitochondrial 16S ribosomal DNA, and cytochrome oxidase subunit I (COI) sequences revealed that these two species have a genetically distant relationship within the genus Palythoa. Morphological characteristics, including polyp size, tentacle number, external/internal coloration, and types and sizes of cnidae were examined in this study. As a result, only tentacle coloration was found to be useful for the morphological distinction between the two species. Palythoa mizigama possesses white tentacles with black horizontal stripes while P. umbrosa possesses white tentacles without any stripe patterns. Considering their distant phylogenetic relationship, it can be assumed that their unique yet similar morphological and ecological characteristics developed independently in each species as an example of parallel evolution

Two new species of Neozoanthus (Cnidaria, Hexacorallia, Zoantharia) from the Pacific

The zoanthid genus Neozoanthus was originally described in 1972 from a single species in Madagascar. This monotypic genus was placed within its own family, Neozoanthidae, given its unusual characters of only partial sand encrustation, and an endodermal sphincter muscle combined with a brachycnemic mesenterial arrangement. Recently, undescribed specimens of Neozoanthus were discovered thousands of kilometers away in both Australia and Japan. While the phylogenetic and evolutionary aspects of Neozoanthus spp. are now somewhat well understood, the new specimens remained undescribed. Here we describe the specimens as two new species, N. uchina sp. n. from the Middle Ryukyu Islands of southern Japan, and N. caleyi sp. n. from the waters around Heron Island, on the Great Barrier Reef in Australia. Both species can be distinguished from each other and the type species, N. tulearensis, by their distributions, oral disk colors, and average numbers of tentacles. Additionally, each species appears to have subtle differences in their cnidae. The division of Japanese and Australian specimens into two species is strongly supported by recently reported phylogenetic data. The discovery and description of these two species highlights how little is known of zoanthid species diversity in the Indo-Pacific

PRELIMINARY LIST OF MACROCNEMIC ZOANTHID DIVERSITY (ANTHOZOA: HEXACORALLIA: ZOANTHARIA) FROM SOUTHERN SHIKOKU, JAPAN

Abstract The oceans of southwestern Shikoku are known for their high levels of marine biodiversity due to the presence of temperate, subtropical, and tropical species. In a previous report, we examined the species diversity of brachycnemic zoanthids (Brachycnemina: Zoantharia: Anthozoa: Cnidaria) in southwestern Shikoku in order to provide basic data for future zoanthid research in the region. However, little information on the other suborder of zoanthids, Macrocnemina, exists for this region. This study, based on surveys conducted between 2006 and 2012, aims to fill this gap by providing a species list of macrocnemic zoanthid species from this region, along with informal descriptions, habitat information, and in situ images. In total, these surveys have recorded eight species from five genera in the southern Shikoku region; Epizoanthus ramosus, Epizoanthus sp. C, Epizoanthus sp. S, Parazoanthus sp., Parazoanthus aff. puertoricense, Savalia sp., Antipathozoanthus sp., and Hydrozoanthus gracilis. However, as most specimens were acquired by snorkeling and SCUBA, only the shallowest and most accessible areas have been examined, and it is very likely that the total species diversity of macrocnemic zoanthids in southern Shikoku is much higher than indicated here

Shallow-Water Brachycnemic Zoanthids (Cnidaria: Hexacorallia) from Taiwan: A Preliminary Survey

(2011) Shallow-water brachycnemic zoanthids (Cnidaria: Hexacorallia) from Taiwan: a preliminary survey. Zoological Studies 50(3): 363-371. Zoanthids are benthic cnidarians commonly seen in shallow coral reef and subtropical marine ecosystems, and are increasingly being utilized as research subjects for marine products and biodiversity studies. However, their distributions and overall species diversity remain relatively unknown except for in a few regions of the world, including southern Japan. Here, for the 1st time, the shallow-water diversity of zoanthids of the suborder Brachycnemina, which primarily includes zooxanthellate species, was examined in Taiwanese waters. Species diversity surveys conducted at coral reef (Kenting and Lyudao) and non-reefal (Keelung) locations revealed 12 zoanthid species (Acrozoanthus australiae, Isaurus tuberculatus, Zoanthus gigantus, Z. kuroshio, Z. sansibaricus, Z. aff. vietnamensis, Palythoa heliodiscus, P. mutuki, P. tuberculosa, Palythoa sp. tokashiki, unknown Palythoa spp., and another unknown zoanthid), most of which are new records for Taiwan. All 3 locations had totals of 7-10 species present, with the 2 coral reef locations resembling locations with coral reefs in Okinawa (e.g., by the presence of Z. kuroshio, P. heliodiscus, Palythoa sp. tokashiki), while the zoanthid community at Keelung was more similar to zoanthids observed at subtropical Shikoku, Japan (e.g., by the presence of Z. aff. vietnamensis and large Z. gigantus colonies). It is possible that the unknown Palythoa specimens constitute 1 or more species new to science, and further investigation of these zoanthids is needed. It is hoped that the species lists provided in this study will help provide a basis for future zoanthid research in Taiwan

The sands of time: rediscovery of the genus Neozoanthus (Cnidaria: Hexacorallia) and evolutionary aspects of sand incrustation in brachycnemic zoanthids

Abstract The zoanthid family Neozoanthidae (Anthozoa: Hexacorallia: Zoantharia) was described in 1973 from Madagascar as a monogeneric and monotypic taxon, and never reported again in literature. In 2008-2010, numerous zoanthid specimens fitting the morphological description of Neozoanthus were collected in the Ryukyu Islands, Okinawa, Japan, and the Great Barrier Reef (GBR), Australia. Utilizing these specimens, this study re-examines the phylogenetic position of Neozoanthidae and analyzes the evolutionary history of sand incrustation in zoanthids through phylogenetic and ancestral state reconstruction analyses. Specimens were colonial, partially incrusted with large, irregular sand and debris, zooxanthellate, and found from the intertidal zone to depths of approximately 30 m. Phylogenetic results utilizing mitochondrial 16S ribosomal DNA and cytochrome oxidase subunit I sequences show the presence of two Neozoanthus species groups, one each from Japan and the GBR. Unexpectedly, the molecular results also show Neozoanthus to be very closely related to the genus Isaurus, which as a member of the family Zoanthidae, is not sand incrusted. These results suggest that during evolution zoanthids can acquire and lose the ability to incrust sand with relative rapidity

Black Coral Assemblages from Machalilla National Park (Ecuador)

Little is known about density and structure of black coral populations of the continental Pacific coasts of Central and South America. Species diversity and ecology of the antipatharian fauna of Machalilla National Park (Province of Manab\ued, Ecuador) were surveyed using scuba, and two species, Myriopathes panamensis and Antipathes galapagensis, were identified. New information on the two species and their associated fauna was obtained through both underwater observations and laboratory analyses. Specific associations with stalked barnacles and parasitic zoanthids are described. An underwater visual census indicated that the black coral assemblage had a maximal density between depths of 15 and 30 m. Myriopathes panamensis commonly occurred below 20 m depth, and A. g alapagensis was mainly recorded from deeper than 25 m depth. Surveyed sites were characterized by sparse rocks mixed with sandy patches, and occurrence of black corals was mainly related to availability of rocky substrate. With an average density of 0.5 colonies m 122, the shallow black coral community of Machalilla National Park is one of the densest in the world. Data from this study represent a clear baseline for monitoring of population dynamics of benthic organisms in an area subjected to periodic El Ni\uf1o and La Ni\uf1a events, which may greatly affect composition and abundance of the marine communities