Labrid Fishes Research Articles

Halichoeres sanchezi n. sp., a new wrasse from the Revillagigedo Archipelago of Mexico, tropical eastern Pacific Ocean (Teleostei: Labridae).

A new labrid fish species, Halichoeres sanchezi n. sp., is described from eight specimens collected in the Revillagigedo Archipelago in the tropical eastern Pacific Ocean, off the coast of Mexico. The new species belongs to the Halichoeres melanotis species complex that is found throughout the region, differing by 2.4% in the mtDNA cytochrome c oxidase I sequence from its nearest relative, H. melanotis from Panama, and 2.9% from Halichoeres salmofasciatus from Cocos Island, off Costa Rica. The complex is distinguished from others in the region by having a black spot on the opercular flap and a prominent black area on the caudal fin of males. The juveniles and initial phase of the new species closely resemble those of H. salmofasciatus and Halichoeres malpelo from Malpelo Island of Colombia, differing in having an oblong black spot with a yellow dorsal margin on the mid-dorsal fin of initial-phase adults as well as on juveniles. In contrast, the terminal-phase male color pattern is distinct from other relatives, being vermilion to orangish brown with dark scale outlines, a white patch on the upper abdomen, and a prominent black band covering the posterior caudal peduncle and base of the caudal fin. The new species adds to the list of endemic fish species for the isolated archipelago and is an interesting case of island endemism in the region. The discovery was made during the joint 2022 collecting expedition to the archipelago, which featured a pioneering collaborative approach to an inventory of an island ichthyofauna, specifically including expert underwater photographers systematically documenting specimens in situ, before hand-collection, and then photographed fresh, tissue-sampled, and subsequently vouchered in museum collections.

First Report on Two Labrid Fishes of the Genera Cirrhilabrus and Paracheilinus from the Bay of Bengal, India

First Report on Two Labrid Fishes of the Genera Cirrhilabrus and Paracheilinus from the Bay of Bengal, India

Scaphanocephalus spp. (Trematoda: Opisthorchiidae) in intermediate and definitive hosts of the Yucatán Peninsula, Mexico, with a re-description of Scaphanocephalus expansus

Summary Scaphanocephalus is a small trematode genus belonging to the family Opistorchiidae. The genus currently contains only three species associated with marine fish as intermediate hosts and fish-eating birds as definitive hosts. Here, specimens of Scaphanocephalus were collected from the Osprey, Pandion haliaetus, and the White mullet, Mugil curema in the Yucatán Peninsula, Mexico. We report for the first-time DNA sequences of adult specimens of Scaphanocephalus, particularly S. expansus, as well as a sequence of a different species sampled as metacercaria. Morphological comparisons of Scaphanocephalus expansus confirmed the identity of the adult specimens, with minor morphological variations; Scanning electron photomicrographs were included, and the species was re-described. Phylogenetic analysis based on 28S rDNA sequences showed that Scaphanocephalus is monophyletic within Opisthorchiidae and consists of three independent lineages. Sequences of adults are identical to those of S. expansus. Instead, the sequence of the metacercaria sampled from the mesentery of Mugil curema nested with specimens reported as Scaphanocephalus sp. from a labrid fish in the Mediterranean Sea, herein named it as Scaphanocephalus sp. 2.

Terelabrus toretore sp. nov. (Perciformes: Labridae), a New Species of Striped Hogfish from Tahiti, with Range Extensions for Two Congeners.

A new labrid fish, Terelabrus toretore sp. nov., the fifth species within the genus, is herein described from two specimens collected at a depth of 140 m from a mesophotic coral ecosystem in Tahiti, French Polynesia. Terelabrus toretore sp. nov. is characterized by having 43-44 scaled rows in longitudinal series; 42 pored lateral-line scales; 5+10 gill rakers; 10 scale rows below the lateral line; 8 posterior branches on the main supratemporal sensory canal; a relatively long snout (snout length 9.6-9.7% SL), and a coloration consisting of a yellow caudal fin and a wide, red, mid-lateral stripe with no blotching, the space above which is white anteriorly, becoming predominantly yellow from beneath the dorsal fin to the caudal peduncle. In addition to describing this new species, we document the first record of Terelabrus rubrovittatus from the Republic of Marshall Islands, and the first record of Terelabrus zonalis from Australia, along with the first description of its coloration. We present a molecular phylogeny of the genus based upon mitochondrial cytochrome c oxidase subunit I (COI) DNA sequences.

Concordance and Discordance in the Phylogenomics of the Wrasses and Parrotfishes (Teleostei: Labridae).

Phylogenomic analysis of large genome-wide sequence data sets can resolve phylogenetic tree topologies for large species groups, help test the accuracy of and improve resolution for earlier multi-locus studies and reveal the level of agreement or concordance within partitions of the genome for various tree topologies. Here we used a target-capture approach to sequence 1088 single-copy exons for more than 200 labrid fishes together with more than 100 outgroup taxa to generate a new data-rich phylogeny for the family Labridae. Our time-calibrated phylogenetic analysis of exon-capture data pushes the root node age of the family Labridae back into the Cretaceous to about 79 Ma years ago. The monotypic Centrogenys vaigiensis, and the order Uranoscopiformes (stargazers) are identified as the sister lineages of Labridae. The phylogenetic relationships among major labrid subfamilies and within these clades were largely congruent with prior analyses of select mitochondrial and nuclear datasets. However, the position of the tribe Cirrhilabrini (fairy and flame wrasses) showed discordance, resolving either as the sister to a crown julidine clade or alternatively sister to a group formed by the labrines, cheilines and scarines. Exploration of this pattern using multiple approaches leads to slightly higher support for this latter hypothesis, highlighting the importance of genome-level data sets for resolving short internodes at key phylogenetic positions in a large, economically important groups of coral reef fishes. More broadly, we demonstrate how accounting for sources of biological variability from incomplete lineage sorting and exploring systematic error at conflicting nodes can aid in evaluating alternative phylogenetic hypotheses. [coral reefs; divergence time estimation; exon-capture; fossil calibration; incomplete lineage sorting.].

Mosaic Evolution of the Skull in Labrid Fishes Involves Differences in Both Tempo and Mode of Morphological Change.

Modularity is a ubiquitous feature of organismal design that plays an important role in structuring patterns of morphological diversification. Modularity can facilitate evolutionary changes by allowing subsets of traits to coevolve as integrated units and follow quasi-independent evolutionary trajectories, a pattern that may be particularly consequential in the case of highly complex morphological structures. Here we examine modularity in a complex and highly kinetic structure, the teleost skull, and ask if a modular organization of the skull has influenced the diversification dynamics of the shapes of its osteological components across the labrid phylogeny. We compiled one of the largest 3D morphological data sets of fishes to date and used geometric morphometrics to quantify patterns of cranial shape evolution across 184 species of wrasses (Labridae). We then tested several hypotheses of modularity inspired by functional and developmental relationships between cranial bones and compared phenotypic rates among modules. We also compared the fit of models of trait evolution for the entire skull and the various articulated bones that it comprises. Our analyses indicated strong support for a 2-module hypothesis, one that encompasses the oral and pharyngeal jaws and another module comprised of the neurocranium, hyoid apparatus, and operculum. This functional hypothesis yielded one of the highest significant rate differentials across modules, yet we also found that the best-fitting models of trait evolution differed among skull bones. These results suggest that modularity can influence morphological diversification in complex biological structures via differences in both the tempo and mode of evolutionary change. [3D geometric morphometrics, cranial morphology, evolutionary modularity, Labridae, phenotypic rates, structural complexity.].

First record of the speckled Maori wrasse, Oxycheilinus arenatus (Valenciennes, 1840) (Actinopterygii: Perciformes: Labridae), from Indian coastal waters

The labrid fish species Oxycheilinus arenatus (Valenciennes, 1840) is recorded for the first time from India’s southeast coast. A total of three specimens were collected as trawl bycatch at Tuticorin, Tamil Nadu, southeast coast of India, in December 2021. The standard length of the specimens ranged from 15.42 to 19.5 cm SL. The presently reported finding of this species from the southeastern coast of India expands and confirms the known distribution range of O. arenatus, which was previously not known from India.

Redescription of Conniella apterygia Allen and its reassignment in the genus Cirrhilabrus Temminck and Schlegel (Teleostei: Labridae), with comments on cirrhilabrin pelvic morphology

Conniella apterygia is redescribed from re-examination of the holotype, two paratypes, and six additional specimens. The genus is closely allied to Cirrhilabrus, sharing similarities in general morphological and meristic details, but is separated from Cirrhilabrus and most other labrid fishes in lacking pelvic fins and a pelvic girdle. Recent molecular phylogenetic studies have provided strong evidence for the deep nesting of Conniella within Cirrhilabrus, contradicting its generic validity and suggesting that the loss of pelvic elements is autapomorphic. Consequently, the species is redescribed and assigned to the genus Cirrhilabrus, as Cirrhilabrus apterygia new combination. The pelvic morphologies of related cirrhilabrin labrids are discussed, and a new synapomorphy is identified for Paracheilinus.

The first record of the lessepsian migrant Pteragogus trispilus Randall 2013 (Osteichthyes: Labridae) off the Libyan coast, east Mediterranean Sea

The Red and Mediterranean seas are connected by the Suez Canal. Since its opening, the Canal has been regarded as a hotbed for invading alien species. During the lessepsian migration, species find their way into the Mediterranean waters and the opposite rarely happens. A single specimen of the Lessepsian migrant labrid fish was obtained at a depth of 20 m during a fishing field trip in Al-Bardi region near the Libyan-Egyptian border. The fish sample was transported to the laboratory (Marine Resources Department, Faculty of Natural Resources and Environmental Sciences, Tobruk University, Tobruk, Libya) and subjected to morphometric and meristic measurements to facilitate its identification. The scientific identification has verified that the caught fish is Pteragogus trispilus belonging to family Labridae. This is the first record of Pteragogus trispilus in the east Mediterranean Sea off the Libyan coast.

Redescription of Cirrhilabrus solorensis Bleeker, with Description of Two New Species of Fairy Wrasses (Teleostei: Labridae: Cirrhilabrus)

The labrid fish Cirrhilabrus solorensis was first described in 1853 by Bleeker, based on specimens collected from the Indonesian island of Solor, off the eastern tip of Flores in the Lesser Sunda Islands. Although sufficient at the time, Bleeker's description of the species was brief, resulting in subsequent taxonomic confusion concerning the true identity of this taxon. Presently, the name has been applied to several fishes with notable differences in coloration, particularly in the terminal males. On the basis of additional non-type material and photographic examination of Bleeker's holotype, we redescribe Cirrhilabrus solorensis and resolve the long-standing contention regarding its taxonomic identity. In doing so, we describe two species as new, Cirrhilabrus aquamarinus, new species, on the basis of the holotype and eight paratypes from Sulawesi and the surrounding islands of Banggai and Wakatobi, Indonesia, and Cirrhilabrus chaliasi, new species, described on the basis of the holotype and nine paratypes from Bali, Indonesia. These three species are closely related and, together with C. aurantidorsalis, C. cyanopleura, C. luteovittatus, C. randalli, and C. ryukyuensis, form a complex of species that differ from congeners in having the following combination of characters: caudal fin in males weakly rhomboidal; median fins hyaline with sinuous filigree in both sexes; body with scales edged in inky blue to indigo, their margins often patterned in an argyle motif; and osseus elements that preserve blue to blue-green in alcohol. We briefly discuss the phylogenetic relationships of species in this complex based on results of a companion study detailed elsewhere.

Size, age, and social control of protogynous sex change in the labrid fish Pteragogus aurigarius

The labrid fish Pteragogus aurigarius undergoes protogynous (female-to-male) sex change, with dichromatic and dimorphic differences in sexes. Similar to some other protogynous fishes, this species is polygynous. We report the size and age at which sex change occurs by monthly sampling fishes at Tateyama, central Japan, from 2011 to 2012, and investigate conditions of sex change in rearing experiments from 2013 to 2015. Sexual phases are determined using gonad histology, and ages by otolith analysis. Of 231 sampled specimens, 99 were female, 129 were male, and three were intersexual. Of males, 86 resembled typical males, and are referred to as “normal males (NM)”, and 43 resembled females in color, which we refer to as “males with female appearance (MFA)”. NM sizes exceeded those of female, intersexual and MFA individuals. Because intersexual and MFA individuals did not differ in color or size, they may have recently transitioned to being male. Intersexual and MFA individuals ranged 85–135 mm in total length and 1–3 years in age, and appeared from September to March. Because the spawning season runs from June to September, sex change must occur afterwards. Sex change occurred in solitary females, and larger females held with other females in aquaria, both with and without aquarium partitions. Size hierarchy in social groups may be important for sex change of the largest female to male regardless of the number of individuals present.

Digenean Parasites of Labrid Fishes (Labridae: Symphodus) from Turkish Coasts of the Black Sea: New Records

In the present study digenean parasite faunas of four labrid fishes, Symphodus tinca, S. rossali, S. cinereus and S. ocellatus were investigated and compared. A total of 52 fish specimens were caught on the Black Sea coast near Sinop, Turkey, over two years. Eight digenean species were found in the four labrid fishes. These are Helicometra fasciata, Gaevskajatrema perezi, Proctoeces maculatus, Phyllodistomum crenilabri, Galactosomum lacteum, Condylocotyla pilodora, Metadena pauli and Opecoelidae gen. sp. Each digenean species on their respective hosts were counted, their prevalence, mean intensity and abundance values were determined. While the maximum parasite diversity was found in S. tinca, S. ocellatus was infected with the fewest parasites. Total parasite abundance was significantly high in S. roissali, which was infected with four species. A close resemblance was observed in the digenean parasite faunas of S. tinca and S. roissali. The core, secondary, satellite, and rare species in the digenean parasite community of each host were determined. This study contains the first data on the digenean parasites of labrid fish on Turkish Black Sea coast. Phyllodistomum crenilabri and Metadena pauli are new parasite records in Turkish fish parasite fauna, while Condylocotyla pilodora is a new parasite record for the labrid fishes.

The awakening of invertebrates: The daily dynamics of fishes and mobile invertebrates at Rapa Nui's multiple use marine protected area

Abstract On shallow reefs, day‐night activity patterns between fishes and invertebrates are presumed to reflect trade‐offs between feeding and predation; however, quantitative data on daily community dynamics are scarce. Moreover, night surveys may contribute important information for biodiversity inventories or baselines that normally are not considered. This study used standardized day–night visual surveys of fishes and mobile invertebrates on the same transect lines in Rapa Nui (Easter Island) and investigated how diel patterns vary between taxonomic and trophic groups. Distinct differences between taxonomic groups were observed, with fishes being more abundant during the day (>twice), whilst invertebrate abundance and richness showed an opposite trend with higher numbers at night (>three times). Analysis of trophic groups showed that herbivorous and planktivorous fishes were more abundant during the day. Carnivorous fishes did not show any trends. Top predators (Apex) were observed only at very low abundances. However, a replacement amongst carnivorous fish species between day and night was found, where labridae fishes were practically absent during nights. Most of the mobile invertebrates remained concealed during the day, probably due to the influence of predation risk (labrid fishes). The results emphasize the need for consideration of nocturnally active invertebrates in biodiversity inventories or baselines of reefs, which focus heavily only on diurnal surveys. Day–night reef surveys should be included in marine protected area planning and monitoring as this provides a better understanding of shallow benthic communities and helps inform proper management decisions.

Complete mitochondrial genome of redbreast Wrasse Cheilinus fasciatus (Bloch, 1791) and its phylogenetic status within the family Labridae

In order to improve our understanding of the characterization of Cheilinus fasciatus mitogenome and the classification status in Labridae, the full-length mtDNA of C. fasciatus was sequenced, which is 16,872 bp in length with the higher A + T content (53%). It is composed of 37 typical vertebrate mitochondrial genes and a noncoding control region (D-loop). Except for the ND6 gene and eight tRNAs, the rest of the genes are encoded on the heavy strand (H-strand). Subsequent phylogenetic analyses support that C. fasciatus belongs to the genus Cheilinus, which is closely related to two genera (Chlorurus and Scarus). The present study will provide important information for future understanding evolutionary theory, population molecular genetics and biological taxonomy of labrid fish.

Colour dimorphism in labrid fishes as an adaptation to life on coral reefs.

Conspicuous coloration displayed by animals that express sexual colour dimorphism is generally explained as an adaptation to sexual selection, yet the interactions and relative effects of selective forces influencing colour dimorphism are largely unknown. Qualitatively, colour dimorphism appears more pronounced in marine fishes that live on coral reefs where traits associated with strong sexual selection are purportedly more common. Using phylogenetic comparative analysis, we show that wrasses and parrotfishes exclusive to coral reefs are the most colour dimorphic, but surprisingly, the effect of habitat is not influenced by traits associated with strong sexual selection. Rather, habitat-specific selective forces, including clear water and structural refuge, promote the evolution of pronounced colour dimorphism that manifests colours less likely to be displayed in other habitats. Our results demonstrate that environmental context ultimately determines the evolution of conspicuous coloration in colour-dimorphic labrid fishes, despite other influential selective forces.

Thermal acclimation leads to variable muscle responses in two temperate labrid fishes.

Temperature can be a key abiotic factor in fish distribution, as it affects most physiological processes. Specifically, temperature can affect locomotor capabilities, especially as species are exposed to temperatures nearing their thermal limits. In this study, we aimed to understand the effects of temperature on muscle in two labrids that occupy the Northwest Atlantic Ocean. When exposed to cold temperatures in autumn, cunner (Tautogolabrus adspersus) and tautog (Tautoga onitis) go into a state of winter dormancy. Transitions into dormancy vary slightly, where tautog will make short migrations to overwintering habitats while cunner overwinter in year-round habitats. To understand how muscle function changes with temperature, we held fish for 4weeks at either 5 or 20°C and then ran muscle kinetic and workloop experiments at 5, 10 and 20°C. Following experiments, we used immunohistochemistry staining to identify acclimation effects on myosin isoform expression. Muscle taken from warm-acclimated cunner performed the best, whereas there were relatively few differences among the other three groups. Cunner acclimated at both temperatures downregulated the myosin heavy chain, suggesting a transition in fiber type from slow-oxidative to fast-glycolytic. This change did not amount to a detectable difference in muscle power production and kinetics. However, overall poor performance at cold temperatures could force these fishes into torpor to overwinter. Tautog, alternatively, retained myosin heavy chains, which likely increases locomotor capabilities when making short migrations to overwintering habitats.

Identification key by scales differentiation for some labrid fishes, Red Sea, Egypt

Identification key by scales differentiation for some labrid fishes, Red Sea, Egypt

Do Coral Reefs Promote Morphological Diversification? Exploration of Habitat Effects on Labrid Pharyngeal Jaw Evolution in the Era of Big Data.

Coral reefs are complex marine habitats that have been hypothesized to facilitate functional specialization and increased rates of functional and morphological evolution. Wrasses (Labridae: Percomorpha) in particular, have diversified extensively in these coral reef environments and have evolved adaptations to further exploit reef-specific resources. Prior studies have found that reef-dwelling wrasses exhibit higher rates of functional evolution, leading to higher functional variation than in non-reef dwelling wrasses. Here, we examine this hypothesis in the lower pharyngeal tooth plate of 134 species of reef and non-reef-associated labrid fishes using high-resolution morphological data in the form of micro-computed tomography scans and employing three-dimensional geometric morphometrics to quantify shape differences. We find that reef-dwelling wrasses do not differ from non-reef-associated wrasses in morphological disparity or rates of shape evolution. However, we find that some reef-associated species (e.g., parrotfishes and tubelips) exhibit elevated rates of pharyngeal jaw shape evolution and have colonized unique regions of morphospace. These results suggest that while coral reef association may provide the opportunity for specialization and morphological diversification, species must still be able to capitalize on the ecological opportunities to invade novel niche space, and that these novel invasions may prompt rapid rates of morphological evolution in the associated traits that allow them to capitalize on new resources.

Experiments reveal limited top-down control of key herbivores in southern California kelp forests.

Predator responses to gradients in prey density have important implications for population regulation and are a potential structuring force for subtidal marine communities, particularly on rocky reefs where herbivorous sea urchins can drive community state shifts. On rocky reefs in southern California where predatory sea otters have been extirpated, top-down control of sea urchins by alternative predators has been hypothesized but rarely tested experimentally. In laboratory feeding assays, predatory spiny lobsters (Panulirus interruptus) demonstrated a saturating functional response to urchin prey, whereby urchin proportional mortality was inversely density-dependent. In field experiments on rocky reefs near San Diego, California, predators (primarily the labrid fish California sheephead, Semicossyphus pulcher) inflicted highly variable mortality on purple urchin (Strongylocentrotus purpuratus) prey across all density levels. However, at low to moderate densities commonly observed within kelp forests, purple urchin mortality increased to a peak at a density of ~11 urchins/m2 . Above that level, at densities typical of urchin barrens, purple urchin mortality was density-independent. When larger red urchins (Mesocentrotus franciscanus) were offered to predators simultaneously with purple urchins, mortality was density-independent. Underwater videography revealed a positive relationship between purple urchin density and both the number and richness of fish predators, but these correlations were not observed when red urchins were present. Our results demonstrate highly variable mortality rates across prey densities in this system and suggest that top-down control of urchins can occur only under limited circumstances. Our findings provide insight into the dynamics of alternate community states observed on rocky reefs.

Prepared for the future: A strong signal of evolution toward the adult benthic niche during the pelagic stage in Labrid fishes.

The morphology of organisms reflects a balance between their evolutionary history, functional demands, and biomechanical constraints imposed by the immediate environment. In many fish species, a marked shift in the selection regime is evident when pelagic larvae, which swim and feed in the open ocean, settle in their adult benthic habitat. This shift is particularly dramatic in coral-reef fishes, where the adult habitat is immensely complex. However, whether the adult trophic ecotype affects the morphology of early-life stages is unclear. We measured a suite of 26 functional-morphological traits in the head and body of larvae from an ontogenetic series of 16 labrid species. Using phylogenetic comparative methods, we reconstructed the location of adaptive peaks of larvae whose adults are associated with different trophic ecotypes. We found that the morphospace occupation in these larvae is largely driven by divergent adaptations to the adult benthic habitats. The disparity between adaptive peaks is achieved early and does not monotonically increase with size. Our findings thus refute the notion that larvae rapidly acquire the trophic-specific traits during a metamorphic period immediately prior to settlement. This early specialization might be due to the highly complex musculoskeletal system of the head that cannot be rapidly modified.