Frank Pezold

Evidence for a monophyletic Gobiinae

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Aquatic Biota of Mexico, Central America and the West Indies

The Cuhcidae are one of the most readily recognized families of nematocerous Diptera. Adults are distinguished from those of the closely related Dixidae and Chaobotidae by the proloagatioa of the mouthparts into a proboscis and presence of scales on the veins of the wings. The pupae have the respiratory trumpet open at the tip and the spiracular opening at its base. In the larva, the 3 segments of the thorax are fused, and the antennae are not prehensile.

Evolution of microhabitat association and morphology in a diverse group of cryptobenthic coral reef fishes (Teleostei: Gobiidae: Eviota)

Gobies (Teleostei: Gobiidae) are an extremely diverse and widely distributed group and are the second most species rich family of vertebrates. Ecological drivers are key to the evolutionary success of the Gobiidae. However, ecological and phylogenetic data are lacking for many diverse genera of gobies. Our study investigated the evolution of microhabitat association across the phylogeny of 18 species of dwarfgobies (genus Eviota), an abundant and diverse group of coral reef fishes. In addition, we also explore the evolution of pectoral fin-ray branching and sensory head pores to determine the relationship between morphological evolution and microhabitat shifts. Our results demonstrate that Eviota species switched multiple times from a facultative hard-coral association to inhabiting rubble or mixed sand/rubble habitat. We found no obvious relationship between microhabitat shifts and changes in pectoral fin-ray branching or reduction in sensory pores, with the latter character being highly homoplasious throughout the genus. The relative flexibility in coral-association in Eviota combined with the ability to move into non-coral habitats suggests a genetic capacity for ecological release in contrast to the strict obligate coral-dwelling relationship commonly observed in closely related coral gobies, thus promoting co-existence through fine scale niche partitioning. The variation in microhabitat association may facilitate opportunistic ecological speciation, and species persistence in the face of environmental change. This increased speciation opportunity, in concert with a high resilience to extinction, may explain the exceptionally high diversity seen in Eviota compared to related genera in the family.

Gobies are deeply divided: phylogenetic evidence from nuclear DNA (Teleostei: Gobioidei: Gobiidae)

Gobies (Gobiidae sensu Gill & Mooi, 2012) are one of the most diverse families of vertebrates, and comprise over 1700 species of marine, brackish and freshwater fishes. Phylogenetic studies based on morphological characters and mtDNA have suggested that goby diversity is asymmetrically split between a speciose clade of predominantly marine species, and a less rich, but ecologically diverse, clade comprising predominantly freshwater and brackish species. This study is the first to explore this deep divide in gobies and their relationships at the family level using phylogenetic data from nuclear genes (RAG1, rhodopsin). Our results confirm the split within the Gobiidae, and agree with prior molecular studies on the inclusion of the following taxa within the two goby clades: (i) the more diverse of the two clades of gobies (the ‘Gobiidae’ sensu stricto of Thacker 2009) comprises the gobiines, microdesmines, ptereleotrines and kraemeriines; (ii) the less diverse of the two gobiid clades (‘Gobionellidae’ sensu Thacker 2009) includes the gobionellines, oxudercines, amblyopines, sicydiines, as well as the European sand gobies. Some relationships within the two major gobiid clades remain unclear. Specifically, there remains confusion regarding the monophyly and interrelationships between the northern Pacific gobionellines, the Mugilogobius group gobionellines, and the European sand gobies. Additionally, within Thackers (2009) Gobiidae sensu stricto, there are several well-supported groups (e.g. the wormfishes and dartfishes, the Coral Gobies, the Gobiosomatini), yet relationships among these groups are still poorly resolved despite the use of data from two conserved nuclear genes. Future phylogenetic analyses of gobies will benefit greatly from taxon sampling that includes groups that have been historically under-represented in molecular studies (e.g. European sand gobies, northern Pacific gobionellines, African species), as well as deeper genetic sampling including large numbers of independent loci from throughout the genome (i.e. a phylogenomic approach).

Cryptobenthic fish biodiversity and microhabitat use in healthy and degraded coral reefs in SE Sulawesi, Indonesia

Cryptobenthic fishes occur in high densities on coral reefs, though due to their small size and cryptic nature they are often overlooked when quantifying reef biodiversity. This study examines their distribution on shallow reefs in SE Sulawesi, Indonesia, and assesses changes in habitat utilization when subject to reef degradation. Cryptic fishes were sampled from dominant microhabitat types in healthy and degraded reefs within the Wakatobi Marine National Park located in SE Sulawesi. High biodiversity of cryptobenthic fishes was found with 50 species representing 13 families. Traditional metrics (i.e. density, diversity) showed few differences between healthy and degraded reefs, though further investigations revealed differences occurred in community composition. Additional analyses of individual species demonstrated that reef degradation could have positive or negative effects on populations depending on type and strength of habitat associations. In summary, cryptobenthic fishes are altering their habitat use on degraded reefs, which will likely have repercussions on coral reef dynamics.

Phylogenetic Analysis of the Genus Gobionellus (Teleostei: Gobiidae)

Abstract A cladistic analysis of the gobiid fish genus Gobionellus primarily using characters of the postcranial axial skeleton and the cephalic lateralis system gave evidence that the genus as historically conceived is polyphyletic. Its present recognition relies upon characters common to many species of gobionelline gobies. One group of six species is most closely related to the genus Gobioides. This group includes Gobionellus oceanicus and retains the name Gobionellus. Gobionellus is diagnosed by an extensive oculoscapular canal running from the snout to above the rear margin of the operculum with a unique A‘BCDFHKL’ pore pattern, a distally flared fourth neural spine that is spatulate in five of the six species, a vertical row of neuromasts on the rear field of the operculum, and elongate gill rakers on the anterior surface and lobes on the posterior surface of the epibranchial of the first gill arch. No unequivocal synapomorphies are offered for the genus excluding Gobioides. Fifteen species previously assigned to Gobionellus are more closely related to species in the genera Oxyurichthys, Oligolepis, and Evorthodus. These species are removed to the resurrected genus Ctenogobius of which Ctenogobius fasciatus is the type species. Ctenogobius is diagnosed by an abbreviated oculoscapular canal that terminates above the preoperculum with an A‘BCDFH’ pattern, a simple or triangulate fourth neural spine, a diagonal posterior opercular neuromast row, and a lack of lobes or gill rakers on the anterior surface of the first epibranchial. The lack of lobes or gill rakers on the anterior surface of the first epibranchial is synapomorphic for the genus. One species originally placed in Gobionellus, Oxyurichthys stigmalophius, exhibits two synapomorphies diagnostic of Oxyurichthys—a transversely bifid third neural spine and no preopercular canal. It also shares other derived features found in most species of Oxyurichthys—a rounded margin on the tongue, a membranous crest on the nape, a shortened palatine bone, and a single row of teeth in the upper jaw. Putative synapomorphies of the gobionelline genera Evorthodus, Gobioides, Oligolepis, and Stenogobius are discussed.

Molecular and morphological divergence in the inland silverside (Menidia beryllina) along a freshwater-estuarine interface

Populations that vary across ecological gradients or that have invaded novel habitats are important to elucidate the association between adaptive divergence and gene flow, factors that may play an important role in speciation of silverside fishes. The inland silverside, Menidia beryllina, is an ideal organism for this kind of research, displaying a great diversity in morphology among freshwater and coastal brackish habitats. Using a combination of geometric morphometrics and mitochondrial (mt) DNA, we investigated patterns of variation within and among the nominal freshwater Menidia audens and coastal M. beryllina, spanning the transition from freshwater to tidally influenced semi-brackish waters of the lower Mississippi River to brackish waters of the Lake Pontchartrain estuary. Although we found no evidence for a phylogenetic split between M. audens and M. beryllina, our results indicate that significant genetic divergence corresponds with body shape differences among the two, with a clear distinction at the interface of freshwater and brackish water. Patterns in mtDNA suggest that freshwater populations referred to as M. audens are of recent origin with evidence for habitat-based divergence compared to coastal populations referred to as M. beryllina. Our findings add to a growing body of evidence that ecological shifts, following colonization of novel habitats, may promote rapid adaptive divergence and reduced gene flow among silverside populations in adjacent environmental regimes.

Redescriptions and Synonymies of Species of the American–West African Genus Gobionellus (Teleostei, Gobiidae) with a Key to Species

Abstract The genus Gobionellus and its six included species are diagnosed and redescribed. All species share a unique cephalic lateralis canal structure, which extends from the tip of the snout to above the rear margin of the operculum with an A‘BCDFHKL’ pore pattern; a vertical row of sensory papillae on the rear field of the operculum and transverse suborbital rows; and a blunt, distally flared fourth neural spine that is spatulate in five of the six species. Three species are found in the eastern Pacific Ocean. Gobionellus daguae is known only from the lower portions of rivers in Panama and Colombia. Gobionellus liolepis has been collected in tidepools and on beaches along the coast of Panama, in the Miraflores locks, and over mud habitats up to 20 m deep off El Salvador. The third eastern Pacific species, Gobionellus microdon, is widespread in estuaries and in some fresh waters from Mexico to Ecuador. Gobionellus mystax is a junior synonym of this species. Two species are recognized from the western Atlantic Ocean. Gobionellus oceanicus is found in estuaries and inshore coastal waters from New Jersey to southern Brazil. The other species, Gobionellus stomatus, is limited to Brazilian estuaries. Gobionellus occidentalis is the only member of the genus from western Africa, where it inhabits tropical estuaries and coastal waters. A key to the species is provided.

Phylogeography of Anguilla marmorata (Teleostei: Anguilliformes) from the eastern Caroline Islands

Recent analyses of the tropical giant mottled eel Anguilla marmorata have suggested four to six populations within its Indo-Pacific distribution, including one represented by specimens from Guam, and that the population on Guam includes eels occurring in the eastern Caroline Islands based on morphological similarities. To test this hypothesis, sequences of the entire mitochondrial control region (mtCR) were obtained for 39 eels from Kosrae and Pohnpei, and compared to 267 previously sequenced haplotypes from across the Indo-Pacific Ocean. Results support recognition of two lineages distinctive for the eastern Caroline Islands and Guam, and the likelihood of an additional spawning area in the Indo-Pacific Ocean.

Morphometric and molecular variation in mountain catfishes (Amphiliidae: Amphilius) in Guinea, West Africa

Species of the genus Amphilius are small benthic catfishes that occur throughout tropical Africa and are abundant in the mountain streams of the Fouta Djalon region in Guinea, West Africa. During a 2003 expedition to the area, numerous amphiliid catfish were collected and initial observations revealed a large amount of morphological variation across the sampled basins. These specimens were subjected to a geometric morphometric analysis and standard morphometric analysis. Cytochrome b gene sequences were also obtained and compared among populations. These analyses resulted in the discovery of multiple cryptic taxa within two recognized species, Amphilius platychir and Amphilius rheophilus. The discovery of these taxa is compared with other recent discoveries from the area.