Ballantine, D.L.

Two rarely reported and one newly described species of benthic marine algae are herein recognized from deep-water habitats at Bonaire, representing the first Caribbean reports of each. Archestenogramma profundum is previously known only from its type collection in Bermuda at 17 m depth and the rarely reported Halymenia integra is known originally from its type locality at Cabo Frio, Brazil. Verdigellas discoidea is newly described on the basis of morphological and molecular evidence. It forms flat circular thalli to 6.5 cm in diameter, measuring to 390 μm thick. The disc-like algae are attached by several small holdfasts on the ventral surface, but the margins are mostly free from their substrata.

Keywords: Archestenogramma; Caribbean; Halymenia; macroalgae; Verdigellas

Two rarely reported and one newly described species of benthic marine algae are herein recognized from deep-water habitats at Bonaire, representing the first Caribbean reports of each. Archestenogramma profundum is previously known only from its type collection in Bermuda at 17 m depth and the rarely reported Halymenia integra is known originally from its type locality at Cabo Frio, Brazil. Verdigellas discoidea is newly described on the basis of morphological and molecular evidence. It forms flat circular thalli to 6.5 cm in diameter, measuring to 390 μm thick. The disc-like algae are attached by several small holdfasts on the ventral surface, but the margins are mostly free from their substrata.

Keywords: Archestenogramma; Caribbean; Halymenia; macroalgae; Verdigellas.

Two new species of Ramicrusta (Peysson- neliaceae, Rhodophyta), Ramicrusta bonairensis from Bonaire, The Netherlands Antilles and Puerto Rico and Ramicrusta monensis from Puerto Rico are described on the basis of both morphological and genetic criteria. Both grow closely appressed to their substrata, a characteristic that differs from their Caribbean congener, Ramicrusta tex- tilis, which forms flared or broadly fluted, expanded erect tissue, and is not closely appressed throughout. The new species also share with each other, the character, seen in microscopic sections, of appearing layered due to an abrupt decrease in cell size that occurs in the perithallus. Ramicrusta bonairensis is thicker than R. monensis, form- ing crusts up to 840 μm thick and carposporangia that measure up to 80 μm in length. Ramicrusta monensis is less thick, 585–650 μm, and produces smaller carposporangia, 40–50 μm in length. Overgrowing thalli in R. monensis are commonly observed, frequently resulting in gaps visible in transverse microscopic sections. Irregular perithallial growth may also result in hollow regions. Male gameto- phytes are reported for the first time in R. textilis and in R. monensis. Mixed reproductive phases in individual thalli, with both male gametophytic structures and tetrasporan- gial nemathecia, are also observed in R. monensis. 

Abstract

On the basis of comparative morphological and molecular analyses, a new red algal species in the genus Wrangelia(Wrangeliaceae, Ceramiales) is described from the tropical western Atlantic. Distinctive characteristics of the proposed new species, W. gordoniae, include: overall habit; built up pseudoparenchymatous cortex that is composed of 2, and in localized sites up to 3, layers of cortical cells, with the outermost layer incomplete, composed of smaller, irregular-shaped cells; and spermatangial heads with 5–6 (–7) involucres, each consisting of a single elongate cell. Analyses of SSU sequences of specimens of Wrangelia from Puerto Rico further support the presence of four genetically distinct entities. In addition to numerous recent collections, a number of herbarium specimens from different Caribbean locales previously identified as “W. penicillata” are now recognized to be W. gordoniae. The new species is compared morphologically with other Wrangelia species that also have 5 whorl branchlets per segment and a cortex that partially or wholly covers their axes. A key to the tropical western Atlantic species of Wrangelia is provided.

Quantitative habitat mapping and description form the basis for understanding the provisioning of ecosystem services and habitat connectivity, and hence provide an essential underpinning for marine spatial planning, management and conservation. Based on 869 video stations in a 150 x 200 m grid, we mapped 25.3 km2 of the near-shore island shelf of St. Eustatius at depths ranging 5-30 m. This yielded a coarse-grained map of the principal habitat classes of St. Eustatius’ seascapes. A total of nine principal seafloor habitats were distinguished. Gorgonian reefs amounted to 22% of the Statia Marine Park habitats sampled and were concentrated in the shallow wave-exposed eastern parts of the island (7.7 m average depths). The densest coral “scapes” and seagrass beds of St. Eustatius were concentrated at depths of about 24 m and only amounted to 4 and 5 percent resp. of the island shelf habitats studied. Whereas coral areas were essentially limited to the southern and south-western island shelf areas, seagrass beds were confined to the northern island shelf area. Including patch reef habitats, total hard coral-scape habitat for the St. Eustatius Marine Park amounted to about 19% of the area surveyed and about 475 ha of habitat. Sargassum reef habitat typically occurred at the seaward edge of communities dominated by hard coral growth.