The new species Tosanoides annepatrice sp. n. is described from four specimens collected at depth... more The new species Tosanoides annepatrice sp. n. is described from four specimens collected at depths of 115– 148 m near Palau and Pohnpei in Micronesia. It differs from the other three species of this genus in life color and in certain morphological characters, such as body depth, snout length, anterior three dorsal-fin spine lengths, caudal-fin length, and other characters. There are also genetic differences from the other four species of Tosanoides (d ≈ 0.04–0.12 in mtDNA cytochrome oxidase I). This species is presently known only from Palau and Pohnpei within Micronesia, but it likely occurs elsewhere throughout the tropical western Pacific.
Mesophotic coral ecosystems (MCEs) continue to be understudied, especially in island locations sp... more Mesophotic coral ecosystems (MCEs) continue to be understudied, especially in island locations spread across the Indo-Pacific Ocean. Pohnpei is the largest island in the Federated States of Micronesia, with a well-developed barrier reef, and steep slopes that descend to more than 1,000 m. Here we conducted visual surveys along a depth gradient of 0 to 60 m in addition to video surveys that extend to 130 m, with 72 belt transects and 12 roving surveys using closed-circuit rebreathers, to test for changes in reef fish composition from shallow to mesophotic depths. We observed 304 fish species across 47 families with the majority confined to shallow habitat. Taxonomic and trophic positions at 30 m showed similar compositions when compared against all other depths. However, assemblages were comprised of a distinct shallow (<30 m) and deep (>30 m) group, suggesting 30 m as a transition zone between these communities. Shallow specialists had a high probability of being herbivores and deep specialists had a higher probability of being planktivores. Acanthuridae (surgeonfishes), Holocentridae (soldierfishes), and Labridae (wrasses) were associated primarily with shallow habitat, while Pomacentridae (damselfishes) and Serranidae (groupers) were associated with deep habitat. Four species may indicate Central Pacific mesophotic habitat: Chromis circumaurea, Luzonichthys seaver, Odontanthias borbonius, and an undescribed slopefish (Symphysanodon sp.). This study supports the 30 m depth profile as a transition zone between shallow and mesophotic ecosystems (consistent with accepted definitions of MCEs), with evidence of multiple transition zones below 30 m. Disturbances restricted to either region are not likely to immediately impact the other and both ecosystems should be considered separately in management of reefs near human population centers.
The Gila robusta species complex in the Lower Colorado River Basin has a complicated taxonomic hi... more The Gila robusta species complex in the Lower Colorado River Basin has a complicated taxonomic history. Recent authors have separated this group into three nominal taxa, G. robusta, G. intermedia, and G. nigra, however aside from location, no reliable method of distinguishing individuals of these species currently exists. To assess relationships within this group, we examined morphology of type specimens and fresh material, and used RADseq methods to assess phylogenetic relationship among these nominal species. Maximum likelihood and Bayesian inference tree building methods reveal high concordance between tree topologies based on the mitochondrial and nuclear datasets. Coalescent SNAPP analysis resolved a similar tree topology. Neither morphological nor molecular data reveal diagnostic differences between these species as currently defined. As such, G. intermedia and G. nigra should be considered synonyms of the senior G. robusta. We hypothesize that climate driven wet and dry cycles have led to periodic isolation of population subunits and subsequent local divergence followed by reestablished connectivity and mixing. Management plans should therefore focus on retaining genetic variability and viability of geographic populations to preserve adaptability to changing climate conditions.
Evolutionary genetic patterns in shallow coastal fishes are documented with dozens of studies, bu... more Evolutionary genetic patterns in shallow coastal fishes are documented with dozens of studies, but corresponding surveys of deepwater fishes (>200 m) are scarce. Here we investigate the evolutionary history of deepwater snappers (genus Etelis), comprised of three recognized Indo-Pacific species and one Atlantic con-gener, by constructing a phylogeny of the genus with two mtDNA loci and two nuclear introns. Further, we apply range-wide Indo-Pacific sampling to test for the presence and distribution of a putative cryptic species pair within E. carbunculus using morphological analyses and mtDNA cytochrome b sequences from 14 locations across the species range (N = 1696). These analyses indicate that E. carbunculus is comprised of two distinct, non-interbreeding lineages separated by deep divergence (d = 0.081 in cytochrome b). Although these species are morphologically similar, we identified qualitative differences in coloration of the upper-caudal fin tip and the shape of the opercular spine, as well as significant differences in adult body length, body depth, and head length. These two species have overlapping Indo-Pacific distributions, but one species is more widespread across the Indo-Pacific, whereas the other species is documented in the Indian Ocean and Western Central Pacific. The dated Etelis phylogeny places the cryptic species divergence in the Pliocene, indicating that the biogeographic barrier between the Indian and Pacific Oceans played a role in speciation. Based on historic taxonomy and nomenclature, the species more widespread in the Pacific Ocean is E. carbunculus, and the other species is previously undescribed (referred to here as E. sp.). The Atlantic congener E. oculatus has only recently ($0.5 Ma) diverged from E. coruscans in the Indo-Pacific, indicating colonization via southern Africa. The pattern of divergence at the Indo-Pacific barrier, and Pleistocene colonization from the Indian Ocean into the Atlantic, is concordant with patterns observed in shallow coastal fishes, indicating similar drivers of evolutionary processes.
Luzonichthys seaver, n. sp., is described from two specimens, 42-46 mm standard length (SL) colle... more Luzonichthys seaver, n. sp., is described from two specimens, 42-46 mm standard length (SL) collected from Pohnpei, Micronesia. Collections were made by divers on mixed-gas closed-circuit rebreathers using hand nets at depths of 90-100 m. Luzonichthys seaver is distinct from all other species of the genus in the characters of lateral line scales, gill rakers, pelvic fin length, caudal concavity and coloration. Of the six species of Luzonichthys, it appears to be morphologically most similar to L. earlei and L. whitleyi.
Neoniphon pencei, n. sp., is described from thirteen specimens, 132-197 mm standard length (SL) c... more Neoniphon pencei, n. sp., is described from thirteen specimens, 132-197 mm standard length (SL) collected from mesophotic coral ecosystems (MCEs) at Rarotonga, Cook Islands by divers using mixed-gas closed-circuit rebreathers. It differs from all other species of the genus in number of lateral line scales, scales above and below lateral line, elements of life color, and in COI and cytochrome b DNA sequences. Of the five other known species of Neoniphon, it is most similar to the Indo-Pacific N. aurolineatus and the western Atlantic N. marianus both morphologically and genetically.
Coral reefs are among the most biodiverse and productive ecosystems on the planet. However, our u... more Coral reefs are among the most biodiverse and productive ecosystems on the planet. However, our understanding of these ecosystems and their inhabitants has primarily been gleaned from shallow-water studies (<40 m), while lightdependent corals and the ecosystems they support extend much deeper (e.g., 150 m in some locations). In recent decades, coral reef ecosystems have substantially declined globally due to direct and indirect anthropogenic activities that differentially impact shallow-water habitats. This decline has led to the suggestion that surface-oriented stressors and disturbances may be mediated by depth. The role of deeper coral reef ecosystems, called mesophotic coral ecosystems (MCEs), as refugia for shallow-water species has fueled new investigations into this realm facilitated in part by advances in diving technology and remote observation platforms. The increasing access to these poorly studied ecosystems is revealing new insights into the biodiversity of MCEs as well as that of shallow coral reefs. The upper mesophotic community is largely an extension of the shallow-water coral reef community, much of the flora and fauna are shared across these depths. However, there is a transition with increasing depth to a lower mesophotic community dominated by flora and fauna that are largely endemic to this zone. Investigations are also expanding depth and geographic ranges for many species, and new species are being discovered regularly in MCEs. However, caution must be taken when generalizing due to the geographically and numerically limited nature of these studies.
The new species Tosanoides annepatrice sp. n. is described from four specimens collected at depth... more The new species Tosanoides annepatrice sp. n. is described from four specimens collected at depths of 115– 148 m near Palau and Pohnpei in Micronesia. It differs from the other three species of this genus in life color and in certain morphological characters, such as body depth, snout length, anterior three dorsal-fin spine lengths, caudal-fin length, and other characters. There are also genetic differences from the other four species of Tosanoides (d ≈ 0.04–0.12 in mtDNA cytochrome oxidase I). This species is presently known only from Palau and Pohnpei within Micronesia, but it likely occurs elsewhere throughout the tropical western Pacific.
Mesophotic coral ecosystems (MCEs) continue to be understudied, especially in island locations sp... more Mesophotic coral ecosystems (MCEs) continue to be understudied, especially in island locations spread across the Indo-Pacific Ocean. Pohnpei is the largest island in the Federated States of Micronesia, with a well-developed barrier reef, and steep slopes that descend to more than 1,000 m. Here we conducted visual surveys along a depth gradient of 0 to 60 m in addition to video surveys that extend to 130 m, with 72 belt transects and 12 roving surveys using closed-circuit rebreathers, to test for changes in reef fish composition from shallow to mesophotic depths. We observed 304 fish species across 47 families with the majority confined to shallow habitat. Taxonomic and trophic positions at 30 m showed similar compositions when compared against all other depths. However, assemblages were comprised of a distinct shallow (<30 m) and deep (>30 m) group, suggesting 30 m as a transition zone between these communities. Shallow specialists had a high probability of being herbivores and deep specialists had a higher probability of being planktivores. Acanthuridae (surgeonfishes), Holocentridae (soldierfishes), and Labridae (wrasses) were associated primarily with shallow habitat, while Pomacentridae (damselfishes) and Serranidae (groupers) were associated with deep habitat. Four species may indicate Central Pacific mesophotic habitat: Chromis circumaurea, Luzonichthys seaver, Odontanthias borbonius, and an undescribed slopefish (Symphysanodon sp.). This study supports the 30 m depth profile as a transition zone between shallow and mesophotic ecosystems (consistent with accepted definitions of MCEs), with evidence of multiple transition zones below 30 m. Disturbances restricted to either region are not likely to immediately impact the other and both ecosystems should be considered separately in management of reefs near human population centers.
The Gila robusta species complex in the Lower Colorado River Basin has a complicated taxonomic hi... more The Gila robusta species complex in the Lower Colorado River Basin has a complicated taxonomic history. Recent authors have separated this group into three nominal taxa, G. robusta, G. intermedia, and G. nigra, however aside from location, no reliable method of distinguishing individuals of these species currently exists. To assess relationships within this group, we examined morphology of type specimens and fresh material, and used RADseq methods to assess phylogenetic relationship among these nominal species. Maximum likelihood and Bayesian inference tree building methods reveal high concordance between tree topologies based on the mitochondrial and nuclear datasets. Coalescent SNAPP analysis resolved a similar tree topology. Neither morphological nor molecular data reveal diagnostic differences between these species as currently defined. As such, G. intermedia and G. nigra should be considered synonyms of the senior G. robusta. We hypothesize that climate driven wet and dry cycles have led to periodic isolation of population subunits and subsequent local divergence followed by reestablished connectivity and mixing. Management plans should therefore focus on retaining genetic variability and viability of geographic populations to preserve adaptability to changing climate conditions.
Evolutionary genetic patterns in shallow coastal fishes are documented with dozens of studies, bu... more Evolutionary genetic patterns in shallow coastal fishes are documented with dozens of studies, but corresponding surveys of deepwater fishes (>200 m) are scarce. Here we investigate the evolutionary history of deepwater snappers (genus Etelis), comprised of three recognized Indo-Pacific species and one Atlantic con-gener, by constructing a phylogeny of the genus with two mtDNA loci and two nuclear introns. Further, we apply range-wide Indo-Pacific sampling to test for the presence and distribution of a putative cryptic species pair within E. carbunculus using morphological analyses and mtDNA cytochrome b sequences from 14 locations across the species range (N = 1696). These analyses indicate that E. carbunculus is comprised of two distinct, non-interbreeding lineages separated by deep divergence (d = 0.081 in cytochrome b). Although these species are morphologically similar, we identified qualitative differences in coloration of the upper-caudal fin tip and the shape of the opercular spine, as well as significant differences in adult body length, body depth, and head length. These two species have overlapping Indo-Pacific distributions, but one species is more widespread across the Indo-Pacific, whereas the other species is documented in the Indian Ocean and Western Central Pacific. The dated Etelis phylogeny places the cryptic species divergence in the Pliocene, indicating that the biogeographic barrier between the Indian and Pacific Oceans played a role in speciation. Based on historic taxonomy and nomenclature, the species more widespread in the Pacific Ocean is E. carbunculus, and the other species is previously undescribed (referred to here as E. sp.). The Atlantic congener E. oculatus has only recently ($0.5 Ma) diverged from E. coruscans in the Indo-Pacific, indicating colonization via southern Africa. The pattern of divergence at the Indo-Pacific barrier, and Pleistocene colonization from the Indian Ocean into the Atlantic, is concordant with patterns observed in shallow coastal fishes, indicating similar drivers of evolutionary processes.
Luzonichthys seaver, n. sp., is described from two specimens, 42-46 mm standard length (SL) colle... more Luzonichthys seaver, n. sp., is described from two specimens, 42-46 mm standard length (SL) collected from Pohnpei, Micronesia. Collections were made by divers on mixed-gas closed-circuit rebreathers using hand nets at depths of 90-100 m. Luzonichthys seaver is distinct from all other species of the genus in the characters of lateral line scales, gill rakers, pelvic fin length, caudal concavity and coloration. Of the six species of Luzonichthys, it appears to be morphologically most similar to L. earlei and L. whitleyi.
Neoniphon pencei, n. sp., is described from thirteen specimens, 132-197 mm standard length (SL) c... more Neoniphon pencei, n. sp., is described from thirteen specimens, 132-197 mm standard length (SL) collected from mesophotic coral ecosystems (MCEs) at Rarotonga, Cook Islands by divers using mixed-gas closed-circuit rebreathers. It differs from all other species of the genus in number of lateral line scales, scales above and below lateral line, elements of life color, and in COI and cytochrome b DNA sequences. Of the five other known species of Neoniphon, it is most similar to the Indo-Pacific N. aurolineatus and the western Atlantic N. marianus both morphologically and genetically.
Coral reefs are among the most biodiverse and productive ecosystems on the planet. However, our u... more Coral reefs are among the most biodiverse and productive ecosystems on the planet. However, our understanding of these ecosystems and their inhabitants has primarily been gleaned from shallow-water studies (<40 m), while lightdependent corals and the ecosystems they support extend much deeper (e.g., 150 m in some locations). In recent decades, coral reef ecosystems have substantially declined globally due to direct and indirect anthropogenic activities that differentially impact shallow-water habitats. This decline has led to the suggestion that surface-oriented stressors and disturbances may be mediated by depth. The role of deeper coral reef ecosystems, called mesophotic coral ecosystems (MCEs), as refugia for shallow-water species has fueled new investigations into this realm facilitated in part by advances in diving technology and remote observation platforms. The increasing access to these poorly studied ecosystems is revealing new insights into the biodiversity of MCEs as well as that of shallow coral reefs. The upper mesophotic community is largely an extension of the shallow-water coral reef community, much of the flora and fauna are shared across these depths. However, there is a transition with increasing depth to a lower mesophotic community dominated by flora and fauna that are largely endemic to this zone. Investigations are also expanding depth and geographic ranges for many species, and new species are being discovered regularly in MCEs. However, caution must be taken when generalizing due to the geographically and numerically limited nature of these studies.
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is revealing new insights into the biodiversity of MCEs as well as that of shallow coral reefs. The upper mesophotic community is largely an extension of the shallow-water coral reef community, much of the flora and fauna are shared across these depths. However, there is a transition with increasing depth to a lower mesophotic community dominated by flora and fauna that are largely endemic to this zone. Investigations are also expanding depth and geographic ranges for many species, and new species are being discovered regularly in MCEs. However, caution must be taken when generalizing due to the geographically and numerically limited nature of these studies.
is revealing new insights into the biodiversity of MCEs as well as that of shallow coral reefs. The upper mesophotic community is largely an extension of the shallow-water coral reef community, much of the flora and fauna are shared across these depths. However, there is a transition with increasing depth to a lower mesophotic community dominated by flora and fauna that are largely endemic to this zone. Investigations are also expanding depth and geographic ranges for many species, and new species are being discovered regularly in MCEs. However, caution must be taken when generalizing due to the geographically and numerically limited nature of these studies.