Matthew T. Craig

A molecular phylogeny of the groupers of the subfamily Epinephelinae (Serranidae) with a revised classification of the Epinephelini

The phylogenetic relationships among the fishes in the perciform tribe Epinephelini (Serranidae) have long been poorly understood, in large part because of the numerous taxa that must be considered and the large, circumtropical distribution of the group. In this study, genetic data from two nuclear (Tmo-4C4 and histone H3) and two mitochondrial (16S and 12S) genes were gathered from 155 serranid and acanthomorph species as a means of developing a phylogenetic hypothesis using both maximum-likelihood and -parsimony criteria. The maximum-parsimony analysis recovered 675 most parsimonious trees of length 5703 steps (CI = 0.2523, HI = 0.7477, RI = 0.6582), and the maximum-likelihood analysis recovered 1 tree at −lnLikelihood = 28279.58341. These phylogenetic hypotheses are discussed in light of previous morphological evidence to evaluate the evolutionary history of the group and their implications for the currently recognized taxonomy. Our results question the monophyly of the Serranidae, as well as the genera Cephalopholis, Epinephelus, and Mycteroperca as currently defined. The Serranidae is monophyletic only with the exclusion of the genera Acanthistius and Niphon. We propose a revised classification of the tribe Epinephelini that reflects the hypothesized shared ancestry of the group and recognizes 11 genera: Alphestes, Cephalopholis, Dermatolepis, Epinephelus, Gonioplectrus, Hyporthodus (which is resurrected for 11 species of deep-bodied groupers), Mycteroperca (including 7 species heretofore allocated to Epinephelus), Plectropomus, Saloptia, Triso, and Variola.

Casting the Percomorph Net Widely: The Importance of Broad Taxonomic Sampling in the Search for the Placement of Serranid and Percid Fishes

Abstract The limits and relationships of serranid and percid fishes, in the context of the percomorph radiation, were resolved using 4036 aligned base pairs of mitochondrial and nuclear DNA sequence data for 180 acanthomorph species. Representatives of all major serranid and percid lineages were analyzed along with 91 additional families from six acanthomorph orders and 25 suborders. Percidae was recovered as monophyletic, and the traditional Serranidae was recovered as polyphyletic, forming five clades: Niphon, Acanthistius, Epinephelinae (less Niphon), Anthiinae (less Acanthistius and Zalanthias kelloggi [formerly included in Plectranthias]), Serraninae (including Zalanthias kelloggi). These traditional “percoid” families were separated from all other “percoid” taxa and recovered within a clade composed of the mail-cheeked fishes and their allies. Based on the evidence provided in this molecular study and prior morphological studies, we recommend taxonomic changes to the Perciformes, Percoidei, Trachinoidei, and Serranidae, we resurrect the Epinephelidae and Niphonidae, and we create a new group, the Moronoidei, to reflect our recovered relationships.

Recent invasion of the tropical Atlantic by an Indo-Pacific coral reef fish

The last tropical connection between Atlantic and Indian–Pacific habitats closed c. 2 million years ago (Ma), with the onset of cold‐water upwelling off southwestern Africa. Yet comparative morphology indicates more recent connections in several taxa, including reef‐associated gobies (genus Gnatholepis). Coalescence and phylogenetic analyses of mtDNA cytochrome b sequences demonstrate that Gnatholepis invaded the Atlantic during an interglacial period ∼145 000 years ago (d = 0.0054), colonizing from the Indian Ocean to the western Atlantic, and subsequently to the central (∼100 000 years ago) and eastern Atlantic (∼30 000 years ago). Census data show a contemporary range expansion in the northeastern Atlantic linked to global warming.

A Phylogenetic Test of the Size‐Advantage Model: Evolutionary Changes in Mating Behavior Influence the Loss of Sex Change in a Fish Lineage

The size‐advantage model asserts that mating behavior influences the incidence and direction of sex change in animals. Selection for protogyny (female to male sex change) occurs in mating systems in which large males monopolize and pair spawn with females; however, gonochorism (no sex change) is favored when adults spawn in groups and sperm competition is present. Despite widespread empirical and theoretical support for the model, these predictions have not been tested within a phylogenetic context. Here we show that the loss of sex change within a lineage of reef fishes is influenced by evolutionary changes in two traits related to their mating behavior: mating group structure and sperm competition intensity. Phylogenetic reconstructions of the reproductive evolution of groupers (Epinephelidae) indicate that protogyny and paired spawning are the ancestral conditions for the lineage; both gonochorism and group spawning evolved independently at least four times in three different genera. Evolutionary transformations from protogyny to gonochorism (loss of sex change) are associated with equivalent transformations in mating group structure from paired to group spawning, and sperm competition is considerably higher in gonochoric species than in protogynous species. These results provide explicit phylogenetic support for predictions of the size‐advantage model, demonstrating that selection for protogynous sex change decreases as mating group size and sperm competition intensity increase.

A Tale of Three Tails: Cryptic Speciation in a Globally Distributed Marine Fish of the Genus Seriola

Genetic data are increasingly being applied to re-evaluate past taxonomic hypotheses and better understand the evolutionary patterns and connectivity among regional populations of cosmopolitan species. This is of particular importance for heavily exploited, commercially important species. The phylogenetic structure of the Yellowtail Jack, Seriola lalandi Valenciennes, 1833, was investigated using genetic data from 42 individuals collected from California, the Pacific coast of Baja California (Mexico), the Gulf of California (Mexico), New Zealand, Japan, South Africa, and Chile. An analysis using S. dumerili as an outgroup and combining the sequences of two mitochondrial genes (CR and COI) and four nuclear genes (RAG2, EHHADH, UBE3A, MLL) was used to determine the level of genetic divergence among samples from different geographic regions. Bayesian and Maximum Likelihood analyses utilizing combined mitochondrial gene (mtDNA) or nuclear gene (nucDNA) data supported the existence of multiple regionally restricted clades with mtDNA analysis identifying four major clades and nucDNA supporting three. Both mtDNA and nucDNA trees were very similar in topology, which was reflected in the combined total evidence phylogram. These clades were highly supported with Bayesian posterior and bootstrap probabilities ranging from 90 to 100 percent for the three major clades that were recovered in both mtDNA and nucDNA trees. These clades represent regionally specific specimens collected from the 1) Northeast Pacific, 2) Northwest Pacific, and 3) Southern Hemisphere. Morphometric analysis (MDS and ANOSIM) of available meristic data on the number of soft dorsal-fin rays, anal-fin rays, and total number of gill rakers separated specimens among the three regions identified by genetic analysis (P  =  0.05). Based on the phylogenetic structure within this taxonomic unit as evidenced by genetic data and significant meristic differences among these regional lineages, we conclude that three cryptic species currently bear the name Seriola lalandi Valenciennes, 1833. We propose the resurrection of two currently available names based on nomenclatural priority. The Northwest Pacific species name should revert to Seriola aureovittata Temminck and Schlegel (1845) (type locality Japan), and the Northeast Pacific species to Seriola dorsalis Gill (1863) (type locality Cabo San Lucas, Mexico). Seriola lalandi Valenciennes, 1833 (type locality Brazil) should apply only to the species in the Southern Hemisphere.

The phylogeny of Paralabrax (Perciformes: Serranidae) and allied taxa inferred from partial 16S and 12S mitochondrial ribosomal DNA sequences

Partial sequences of 16S and 12S mitochondrial ribosomal DNA were used to examine the phylogenetic relationships of the primarily eastern Pacific genus Paralabrax (Perciformes: Serranidae) and allied taxa. Paralabrax is considered a basal serranine, which is itself considered the basal subfamily in the Serranidae. Multiple serranines reported closely related to Paralabrax from the genera Serranus, Hypoplectrus, Cratinus, and Centropristis were used as outgroups. Species from the remaining two subfamilies, Epinephilinae and Anthiinae, of the Serranidae were also used in the analyses. The tree of the Serranidae was rooted with the families Polyprionidae and Priacanthidae. Paralabrax, the Serranidae, and the Serraninae were monophyletic in this study. Serranus was found to be paraphyletic. Centropristis, formerly considered the sister taxon to Paralabrax, was not closely related in these analyses. Cratinus agassizii, a monotypic genus from the eastern Pacific, was found to be the sister taxon to Paralabrax. There is greater resolution for intergeneric and subfamily relations than interspecific relationships. A single most parsimonious tree for the interspecific relationships of Paralabrax and allied taxa is proposed. This proposed molecular phylogeny is consistent with known biogeographic processes in the eastern Pacific.

Preliminary observations on the life history of the white-streaked grouper, Epinephelus ongus , from Okinawa, Japan

A preliminary analysis of 175 specimens of the white-streaked grouper, Epinephelus ongus (Serranidae), was undertaken to determine life history characteristics of the species. Sagittal otoliths, stomachs, and a subsample of gonads were removed to determine age at length, diet, and reproductive strategy. The von Bertalanffy growth equation was used to describe growth in this species and yielded the growth parameters L∞ = 438.3, K = 0.04334, and t0 = −8.752. Fish ranged in age from 1 to 20 years. Diet was consistent with other serranid species and included crabs, shrimps, octopi, and fishes. Based on a very limited number of specimens (n = 12), the larger size and older age of males compared to females suggests that E. ongus may be a protogynous hermaphrodite.

Kangaroo Mice (Microdipodops megacephalus) of the Mono Basin: Phylogeography of a Peripheral Isolate

Abstract Kangaroo mice (Microdipodops) inhabiting the Mono Basin and adjoining valley regions of California and Nevada represent a disjunct distributional isolate and have been considered as a distinct species or, more recently, as 2 subspecies of M. megacephalus. Analysis of patterns of geographic variation in 11 populations in the Mono Basin region shows that kangaroo mice inhabiting the northern portion of this peripheral isolate are relatively large and dark (referred to as M. m. nasutus), and those to the southern end are small and pale (termed M. m. polionotus), and a cline exists between the 2. Inasmuch as several morphological characters are correlated positively with environmental measures (e.g., hind-foot length and climatic severity; pelage color and soil color), it appears that variation in morphology is responding to a selection gradient. Mitochondrial DNA sequence data, together with chromosomal and protein information, reveal that the 2 subspecies are nearly identical genetically. Moreover, molecular phylogeographic analysis reveals that the Mono kangaroo mice belong to the southeastern geographic unit of M. megacephalus (a mean of 1.86% sequence divergence) and are genetically most close to animals from the San Antonio locality (more than 100 km to the east). It is hypothesized that distributional shifts in the geographic range of kangaroo mice in response to climatic fluctuation during the late-Pleistocene and Holocene times resulted in the westward expansion and eventual colonization and isolation of kangaroo mice in the Mono Basin region. Our vicariant biogeographical interpretation suggests a historical route through the Lahontan Trough and the physiographic discontinuity east of Mono Lake (i.e., between the Wassuk Range and the White Mountains) that may serve as a biogeographic model for other basin-dwelling organisms. Lastly, the systematic status of the 2 subspecies is evaluated; a single subspecies, polionotus, is recognized, with nasutus placed in synonymy.

Two New Species of the Indo-Pacific Clingfish Genus Discotrema (Gobiesocidae)

Abstract Two new species of the formerly monotypic gobiesocid genus Discotrema are described. Discotrema monogrammum is described from specimens collected from crinoids in Papua New Guinea and Indonesia, with photographic and literature records from the Great Barrier Reef, Philippines, and Christmas Island, Indian Ocean. The specimens were first believed to be a color form of D. crinophilum, described from Fiji and Papua New Guinea, and also commensal in crinoids. Both species have a single, white or pale yellow lateral stripe, whereas D. crinophilum also has a mid-dorsal white stripe; unique mitochondrial DNA sequences showed that D. crinophilum and D. monogrammum are distinct lineages. Discotrema zonatum, which has irregular dark bars on the side of the body, is described from a single specimen from Fiji, apparently commensal on soft coral. The three species are also distinguished by pectoral-fin ray counts and three proportional measurements. Some authors have placed Lepadichthys lineatus in the genus Discotrema, but its disc morphology and other characters indicate that it should remain in Lepadichthys. A key to the species of Discotrema is provided.

Facultative Cleaning by the Forcepsfish, Forcipiger flavissimus (Chaetodontidae)

Abstract On 7 June 2006 a specimen of Forcepsfish, Forcipiger flavissimus, was observed engaging in cleaning behavior of a Bigscale Soldierfish, Myripristis berndti (Holocentridae). This behavior is described here as novel for the species. Anecdotal reports of similar behavior indicate that this species engages in cleaning with several hosts including other fishes and sea turtles. Reports of this behavior at other localities and among a variety of butterflyfish species indicate that cleaning may be a more important foraging strategy than previously thought.