Three reductive specializations (absence of the posterior uroneural, procurrent spur and third preural radial cartilages) define the percoid family Serranidae with respect to the ostensibly polyphyletic Percichthyidae (sensu Gosline, 1966). A single innovative specialization, the presence of three spines on the opercle, indicates that the Serranidae are monophyletic. All members of the serranid subfamily Epinephelinae, comprising five tribes, share a unique modification of the first dorsal pterygiophore, seemingly a specialization for support of the elongate dorsal spine of the larvae. The enigmatic Niphon spinosus, placed in the Percichthyidae by Gosline (1966), and in the Centropomidae by Rivas and Cook (1968), shares the epinepheline specialization, as well as the four specializations that characterize the Serranidae. It is hypothesized that the monotypic Niphon is the sister group of all other epinephelines. Identification of the larva of Niphon could provide corroborative evidence for this hypothesis.

The oceanic bathypelagic realm (1000–4000 m) is a nutrient-poor habitat. Most fishes living there have pelagic larvae using the rich waters of the upper 200 m. Morphological and behavioural specializations necessary to occupy such contrasting environments have resulted in remarkable developmental changes and life-history strategies. We resolve a long-standing biological and taxonomic conundrum by documenting the most extreme example of ontogenetic metamorphoses and sexual dimorphism in vertebrates. Based on morphology and mitogenomic sequence data, we show that fishes currently assigned to three families with greatly differing morphologies, Mirapinnidae (tapetails), Megalomycteridae (bignose fishes) and Cetomimidae (whalefishes), are larvae, males and females, respectively, of a single family Cetomimidae. Morphological transformations involve dramatic changes in the skeleton, most spectacularly in the head, and are correlated with distinctly different feeding mechanisms. Larvae have small, upturned mouths and gorge on copepods. Females have huge gapes with long, horizontal jaws and specialized gill arches allowing them to capture larger prey. Males cease feeding, lose their stomach and oesophagus, and apparently convert the energy from the bolus of copepods found in all transforming males to a massive liver that supports them throughout adult life.

One of the most conspicuous characters of the ocean sunfishes, family Molidae, is the punctuation of the body by a deep, abbreviated, caudal fin-like structure extending vertically between the posterior ends of the dorsal and anal fins, termed the clavus by Fraser Brunner. Homology of the clavus has been a matter of debate since the first studies on molid anatomy in the early 1800s. Two hypotheses have been proposed: 1) It is a highly modified caudal fin; 2) It is formed by highly modified elements of the dorsal and anal fins. To resolve this homology issue, we studied the ontogeny of the molid vertebral column and median fins and compared it to that of a less morphologically derived gymnodont (see Part 1 of this study), a member of the family Tetraodontidae. We show that in molids the chorda never flexes during development, that the claval rays form from the posterior ends of the dorsal and anal fins toward the middle, thus closing the gap inward, and that elements of the molid clavus have an identical development and composition as the proximal-middle and distal radials of the regular dorsal and anal fins. We thus conclude that the molid clavus is unequivocally formed by modified elements of the dorsal and anal fin and that the caudal fin is lost in molids.

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. 1997. Dismantling the Trachinoidei: evidence of a scorpaenoid relationship for the Champsodontidae. Ichthyol. Res., 44 (2): 143-176. AbstractAn examination of the osteology and myology of the Champsodontidae reveals a number of apomorphic features (e.g., double-headed palatine, large pelvic radial, epaxial muscle inserting on the medial pelvic-fin ray, posterior levator internus inserting on the third epibranchial). The evidence for a Champsodontidae/Chiasmodontidae relationship is examined through a re-evaluation of the basal characters used to define the suborder Trachinoidei. The Champsodoutidae are removed from the Trachinoidei and a chiasmodontid sister relationship is rejected. After investigation of severaI possible alternative relationships (Paracanthopterygii, Gobioidei, Callionymoidei, Kurtoidei, Apogonidae, Blennioidei, Trichodontidae), champsodontids are hypothesized to be members of the perciform suborder Scorpaenoidei. This hypothesis is based largely on the synapomorphy of a parietal spine with an opening for passage of the supratemporal sensory canal, a unique condition of champsodontids and some scorpaenoids. A shared Type 1 epaxial muscle morphology, with separate fibre insertions on the distal tips of the spine-bearing dorsal-fin pterygiophores, is unusual and probably derived among perciforms. Champsodontids also share with some scorpaenoids Type 5 spinoid scales and the origin of Baudelot's ligament from the first vertebra rather than the basi-occipital, although neither of these features is unique to these taxa. The occurrence of an enclosed sensory. canal on the parietals of Trichodontidae suggest that their relationships might also lie with the Scorpaenoidei. Arguments pertaining to the removal of champsodontids from the trachinoids apply equally to the hypothesized membership of the Cheimarrichthyidae, Pinguipedidae, Percophididae, Trichonotidae, Creediidae, Chiasmodontidae, and notothenioids in the Trachinoidei. Inclusion of these taxa within the Trachinoidei is not well-supported, and their relationships require further investigation.

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