Carole C. Baldwin

Abstract

Tropical deep reefs (~40–300 m) are diverse ecosystems that serve as habitats for diverse communities of reef-associated fishes. Deep-reef fish communities are taxonomically and ecologically distinct from those on shallow reefs, but like those on shallow reefs, they are home to a species-rich assemblage of small, cryptobenthic reef fishes, including many species from the family Gobiidae (gobies). Here we describe two new species of deep-reef gobies, Varicus prometheus sp. nov. and V. roatanensis sp. nov., that were collected using the submersible Idabel from rariphotic reefs off the island of Roatan (Honduras) in the Caribbean. The new species are the 11th and 12th species of the genus Varicus, and their placement in the genus is supported by morphological data and molecular phylogenetic analyses. Additionally, we also collected new specimens of the closely-related genus and species Pinnichthys aimoriensis during submersible collections off the islands of Bonaire and St. Eustatius (Netherland Antilles) and included them in this study to expand the current description of that species and document its range extension from Brazil into the Caribbean. Collectively, the two new species of Varicus and new records of P. aimoriensis add to our growing knowledge of cryptobenthic fish diversity on deep reefs of the Caribbean.

Submersible diving in the 1980/90s in the Bahamas and Cuba and 2013–2018 at Curaçao, Dominica, and Roatan resulted in the collection of a new species of Polylepion, a genus of wrasse previously known only from the Indian and Pacific Oceans. The new species, which inhabits the rariphotic reef-fish faunal zone at depths of 219–457 m, is another example of a deep-reef species belonging to a largely shallow-reef family, in this case the family Labridae. Here, we describe the new species and provide a phylogenetic placement for it by adding new sequence data from 12 genetic markers for the new species and one of its two congeners (P. cruentum from the eastern Pacific Ocean) to a previously published dataset comprising 336 species of wrasses that includes the other congener, P. russelli, from the Indian and West/Central Pacific Oceans. Our results resolve the phylogenetic history of the species of Polylepion and provide the first molecular support for the monophyly of the genus.

Abstract

1.  Biodiversity inventories and monitoring techniques for marine fishes often over-look small (<5  cm), bottom-associated (‘cryptobenthic’) fishes, and few stand-ardized, comparative assessments of cryptobenthic fish communities exist. We sought to develop a standardized, quantitative survey method for cryptobenthic fishes that permits their sampling across a variety of habitats and conditions.

2.  Fish-   specific autonomous reef monitoring structures (FARMS) are designed to sample cryptobenthic fishes using a suite of accessible and affordable materials. To generate a variety of microhabitats, FARMS consist of three layers of stacked PVC pipes in three different sizes, as well as a bottom and top level of loose PVC pipe fragments in a mesh basket. We deployed FARMS across a variety of habitats, including coral reefs, seagrass beds, oyster reefs, mangroves, and soft- bottom habitats across six locations (Hawai'i, Texas, Panama, Saudi Arabia, Brazil, and Curaçao).

3.  From shallow estuaries to coral reefs beyond 100 m depth, FARMS attracted distinct communities of native cryptobenthic fishes with strong site or habitat speci ficity. Comparing the FARMS to communities sampled with alternative methods (enclosed clove-oil stations on coral reefs in Panama and oyster sampling units on oyster reefs in Texas) suggests that FARMS yield a subset of cryptobenthic fishspecies that are representative of those present on local coral and oyster reefs. While FARMS yield fewer individuals per sample, they are efficient sampling de-vices relative to the sampled area.

4.  We demonstrate that FARMS represent a useful tool for standardized collections of cryptobenthic fishes. While natural substrata are bound to yield more mature communities with a larger number of individuals and wider range of specialist spe-cies, the potential to deploy and retrieve FARMS in turbid environments, beyond regular SCUBA depth, and where fish collections using anaesthetics or ichthyo-cides are forbidden suggests that they are a valuable complementary technique to survey fishes in aquatic ecosystems. Deploying FARMS in locations and habi-tats where cryptobenthic fish communities have not been studied in detail may yield many valuable specimens of unknown or poorly known species.KEYWORDSartificial habitat, biodiversity, biogeography, coral reef fishes, fish trap, fisheries-independent sampling, taxonomic inventory