Baldwin, C.C.

A new species of Chromis damselfish from the tropical western Atlantic (Teleostei, Pomacentridae)

Initially described in 1882, Chromis enchrysurus, the Yellowtail Reeffish, was redescribed in 1982 to account for an observed color morph that possesses a white tail instead of a yellow one, but morphological and geographic boundaries between the two color morphs were not well understood. Taking advantage of newly collected material from submersible studies of deep reefs and photographs from rebreather dives, this study sought to determine whether the white-tailed Chromis is actually a color morph of Chromis enchrysurus or a distinct species. Phylogenetic analyses of mitochondrial genes cytochrome b and cytochrome c oxidase subunit I separated Chromis enchrysurus and the white-tailed Chromis into two reciprocally monophyletic clades. A principal component analysis based on 27 morphological characters separated the two groups into clusters that correspond with caudal-fin coloration, which was either known or presumed based on the specimen’s collection site according to biogeographic data on species boundaries in the Greater Caribbean. Genetic, morphological, and biogeographic data all indicate that the white-tailed Chromis is a distinct species, herein described as Chromis vanbebberae sp. nov. The discovery of a new species within a conspicuous group such as damselfishes in a well-studied region of the world highlights the importance of deep-reef exploration in documenting undiscovered biodiversity.

 

Keywords Caribbean, coral reef, mesophotic, phylogenetics, rariphotic, systematics

Date
2020
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
Curacao
St. Eustatius

Octopods of deep reefs off Curaçao, southern Caribbean, including description of one newly discovered species

Recent exploratory research on poorly studied deep reefs in the Caribbean Sea has yielded substantial new information about the diversity of deep-reef fishes and some invertebrates, but the diversity of deep-reef cephalopods has not been assessed. Using images, videos, and specimens collected with the aid of a manned submersible, as well as DNA sequences derived from the specimens, we surveyed the cephalopod diversity of the mesophotic and rariphotic reef communities at Curacao, southern Caribbean. Among the 50 records comprising 15 specimens, 39 photos, and 15 videos, of which six specimens matched video records, we found Octopus hummelincki Adam 1937, Pteroctopus cf tetracirrhus Delle Chiaje 1830, Scaeurgus unicirrhus Delle Chiaje 1841, Paroctopus mercatoris Adam 1937, and Lepidoctopus joaquini Haimovici and Sales 2019. In addition, we found one group of octopods, with two specimens that did not correspond to any known species. We describe this as a new species. One specimen of Lepidoctopus joaquini was hectocotylized on two arms.

Date
2019
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Curacao

Below the Mesophotic

Mesophotic coral ecosystems, which occur at depths of ~40 to 150 m, have received recent scientific attention as potential refugia for organisms inhabiting deteriorating shallow reefs. These ecosystems merit research in their own right, as they harbor both depth-generalist species and a distinctive reef-fish fauna. Reef ecosystems just below the mesophotic are globally underexplored, and the scant recent literature that mentions them often suggests that mesophotic ecosystems transition directly intothose of the deep sea. Through submersible-based surveys in the Caribbean Sea, we amassed the most extensive database to date on reef-fish diversity between ~40 and 309 m at any single tropical location. Our data reveal a unique reef-fish assemblage living between ~130 and 309 m that, while taxonomically distinct from shallower faunas, shares strong evolutionary affinities with them. Lacking an existing name for this reef-faunal zone immediately below the mesophotic but above the deep aphotic, wepropose “rariphotic.” Together with the “altiphotic,” proposed here for the shallowest reef-faunal zone, and the mesophotic, the rariphotic is part of a depth continuum of discrete faunal zones of tropical reeffishes, and perhaps of reef ecosystems in general, all of which warrant further study in light of globaldeclines of shallow reefs.

Date
2018
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Curacao

More new deep-reef basslets (Teleostei, Grammatidae, Lipogramma), with updates on the eco-evolutionary relationships within the genus

Two new Lipogramma basslets are described, L. barrettorum and L. schrieri, captured during submersible diving to 300 m depth off Curaçao, southern Caribbean. Superficially resembling L. robinsi in having 11–12 bars of pigment on the trunk, L. barrettorum is distinct from L. robinsi in having a stripe of blue-white pigment along the dorsal midline of the head (vs. a cap of yellow pigment), in patterns of pigment on the median fins, and in having 8–10 gill rakers on the lower limb of the first arch (vs. 11–12). Lipogramma schrieri is distinct from all congeners in having seven or eight dark bars of pigment on the trunk and broad, irregular, whitish blue markings on the dorsal portion of the head. The new species are genetically distinct from one another and from seven other Lipogramma species for which genetic data are available. A phylogenetic hypothesis derived from mitochondrial and nuclear genes suggests that the new species belong to a clade that also comprises L. evides and L. haberi. Collectively those four species are the deepest-living members of the genus, occurring at depths predominantly below 140 m. This study thus provides further evidence of eco-evolutionary correlations between depth and phylogeny in Caribbean reef fishes. Tropical deep reefs are globally underexplored ecosystems, and further investigation of Caribbean deep reefs undoubtedly will provide samples of species for which no genetic material currently exists and reveal more cryptic species diversity in the genus.

Date
2018
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
Curacao

High coral cover at lower mesophotic depths: a dense Agaricia community at the leeward side of Curaçao, Dutch Caribbean

Coral cover at lower mesophotic depths (particular- ly >75 m) by zooxanthellate scleractinians is usually very scarce, largely due to the extremely low irradiance levels at these depths. An exception are the Leptoseris communities observed near the Hawaiian islands (Central Pacific) that form dense fields, supporting a broad range of associated organ- isms. Here, we describe a similar high-cover coral community at lower mesophotic depths, but in the Caribbean. The com- munity was observed on the leeward side of Curaçao (Southern Caribbean) using a manned submersible (Curasub), and was predominantly composed of plating Agaricia corals and an assemblage of reef fishes. Some of the fish species were known from similar depths at other lo- calities, whereas others obtained new depth records. Future surveys are required to establish the extent of similar high- coral communities around Curaçao, and more broadly in the western Atlantic. 

Date
2015
Data type
Scientific article
Geographic location
Curacao

Varicus lacerta, a new species of goby (Teleostei, Gobiidae, Gobiosomatini, Nes subgroup) from a mesophotic reef in the southern Caribbean

We describe a new species of goby, Varicus lacerta sp. n., which was collected from a mesophotic reef at Curacao, southern Caribbean. The new species is the tenth species of Varicus, all of which occur below traditional SCUBA depths in the wider Caribbean area. Its placement in the genus Varicus is supported by a molecular phylogenetic analysis of three nuclear genes and the mitochondrial gene cytochrome b. In addition, the new species has one anal-fin pterygiophore inserted anterior to the first haemal spine, which distinguishes Varicus species from most species in the closely related and morphologically similar genus Psilotris. Varicus lacerta sp. n. is distinguished from all other named species of Varicus by the absence of scales, having highly branched, feather-like pelvic-fin rays, and in its live coloration. We provide the cytochrome c oxidase I DNA barcode of the holotype and compare color patterns of all species of Varicusand Psilotris for which color photographs or illustrations are available. This study is one of several recent studies demonstrating the utility of manned submersibles in exploring the diversity of poorly studied but species-rich deep-reef habitats.

Date
2016
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
Curacao

Molecular phylogeny, analysis of character evolution, and submersible collections enable a new classification of a diverse group of gobies (Teleostei: Gobiidae: Nes subgroup), including nine new species and four new genera

The Nes subgroup of the Gobiosomatini (Teleostei: Gobiiformes: Gobiidae) is an ecologically diverse clade of fishes endemic to the tropical western Atlantic and eastern Pacific oceans. It has been suggested that morphological characters in gobies tend to evolve via reduction and loss associated with miniaturization, and this, coupled with the parallel evolution of adaptations to similar microhabitats, may lead to homoplasy and ultimately obscure our ability to discern phylogenetic relationships using morphological characters alone. This may be particularly true for the Nes subgroup of gobies, where several genera that are diagnosed by ‘reductive characters’ have been shown to be polyphyletic. Here we present the most comprehensive phylogeny to date of the Nes subgroup using mitochondrial and nuclear sequence data. We then evaluate the congruence between the distribution of morphological characters and our molecular tree using maximum-likelihood ancestral state reconstruction, and test for phylogenetic signal in characters using Pagel’s k tree transformations (Nature, 401, 1999 and 877). Our results indicate that all of the characters previously used to diagnose genera of the Nes subgroup display some degree of homoplasy with respect to our molecular tree; however, many characters display considerable phylogenetic signal and thus may be useful in diagnosing genera when used in combination with other characters. We present a new classification for the group in which all genera are monophyletic and in most cases diagnosed by combinations of morphological characters. The new classification includes four new genera and nine new species described here, many of which were collected from rarely sampled deep Caribbean reefs using manned submersibles. The group now contains 38 species in the genera Carrigobius gen. nov., Chriolepis, Eleotrica, Gobulus, Gymneleotris, Nes, Paedovaricus gen. nov., Pinnichthys gen. nov., Psilotris, and Varicus. Lastly, we provide a key to all named species of the Nes subgroup along with photographs and illustrations to aid in identification. 

Date
2016
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Curacao

A new deep-reef scorpionfish (Teleostei, Scorpaenidae, Scorpaenodes) from the southern Caribbean with comments on depth distributions and relationships of western Atlantic members of the genus

A new species of scorpionfish, Scorpaenodes barrybrowni Pitassy & Baldwin, sp. n. which is described, was collected during submersible diving in the southern Caribbean as part of the Smithsonian’s Deep Reef Observation Project (DROP). It differs from the other two western Atlantic species of the genus, Scorpaenodes caribbaeus and Scorpaenodes tredecimspinosus, in various features, including its color pattern, having an incomplete lateral line comprising 8–10 pored scales, tending to be more elongate, usually having the 11th–12th pectoral-fin rays elongate, and by 20–23% divergence in the cytochrome c oxidase I (COI) DNA barcode sequences. It further differs from one or the other of those species in head spination and in numbers of soft dorsal-fin rays, pectoral-fin rays, and precaudal + caudal vertebrae. Inhabiting depths of 95–160 m, the new species is the deepest western Atlantic member of the genus (Scorpaenodes caribbaeus occurs at depths < 35 m and Scorpaenodes tredecimspinosus from 7 to 82 m). DNA barcode data do not rigorously resolve relationships among the ten species of the genus for which those data are available.

 

Date
2016
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
Curacao

Deep Reef Observation Project (DROP): a Smithsonian-substation Curacao collaboration

Scientists have studied shallow Caribbean reefs for more than a century. In contrast tropical mesophotic and deep reefs, which are below the depths accessible by traditional scuba gear and above the depths typically visited by deep-diving submersibles, are underexplored ocean ecosystems that science has largely missed. Little is known about the diversity of life on deep reefs, how it changes over space and time, and what role deep reefs may play in the survival of shallow reefs above. Shallow reefs are in peril circumtropically but what is the status of deep reefs? Are water temperatures on deep reefs rising and are these ecosystems exhibiting degradation and loss from major agents of environmental impact? Are shallow reef inhabitants moving deeper in response to warming surface waters? Are deep-reef populations re-seeding shallow populations that have been impacted by reef demise?

 

Date
2013
Data type
Other resources
Theme
Research and monitoring
Geographic location
Curacao
Author

A new Liopropoma sea bass (Serranidae, Epinephelinae, Liopropomini) from deep reefs off Curaçao, southern Caribbean, with comments on depth distributions of western Atlantic liopropomins

Abstract

Collecting reef-fish specimens using a manned submersible diving to 300 m off Curaçao, southern Caribbean, is resulting in the discovery of numerous new fish species. The new Liopropoma sea bass described here differs from other western Atlantic members of the genus in having VIII, 13 dorsal-fin rays; a moderately indented dorsal-fin margin; a yellow-orange stripe along the entire upper lip; a series of approximately 13 white, chevron-shaped markings on the ventral portion of the trunk; and a reddish-black blotch on the tip of the lower caudal-fin lobe. The new species, with predominantly yellow body and fins, closely resembles the other two “golden basses” found together with it at Curaçao: L. aberransand L. olneyi. It also shares morphological features with the other western Atlantic liopropomin genus, Bathyanthias. Preliminary phylogenetic data suggest that western Atlantic liopropomins, including Bathyanthias, are monophyletic with respect to Indo-Pacific Liopropoma, and that Bathyanthias is nested within Liopropoma, indicating a need for further study of the generic limits of Liopropoma. The phylogenetic data also suggest that western Atlantic liopropomins comprise three monophyletic clades that have overlapping depth distributions but different depth maxima (3–135 m, 30–150 m, 133–411 m). The new species has the deepest depth range (182–241 m) of any known western Atlantic Liopropomaspecies. Both allopatric and depth-mediated ecological speciation may have contributed to the evolution of western Atlantic Liopropomini.

 

 

 

Date
2014
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
Curacao