Search

— A cladistic analysis of the eighteen species of Spanish mackerels (Scomberomorus) was conducted using the double-lined mackerel (Grammatorcynus) as the outgroup. Based on fifty-eight osteological and morphological characters, six species groups are recognized. Comparisons of the cladogram for the regalis species group were made with a cladogram of the nine species of parasitic copepods that infest the six members of the regalis group. Incongruences were analyzed. The parasite tree was then “forced” onto the host cladogram to determine which evolutionary events of the parasites could be explained by evolutionary events of the hosts. Hypotheses of coevolution are supported in some cases, hypotheses of dispersal are proposed in others.

This part completes the review of the largest and economically richest order of fishes, Perciformes, begun in Part 3. It includes 12 suborders with keys and brief descriptions to 230 species, and information on their ecology and distribution.

High market values have incentivized extensive fisheries for Pacific bluefin tuna ( Thunnus orientalis , see the photo), a species whose longevity, commercial value, and long generation time make it particularly susceptible to overfishing ( 1 , 2 ). Today, the population of Pacific bluefin tuna stands at an estimated 2.6% of prefished levels ( 1 ). Yet, knowledge of its basic life history is incomplete. Recent studies ( 3 , 4 ) suggest that the fundamental distribution of Pacific bluefin across the North Pacific has been misunderstood. The results underscore the need for basic movement ecology information to assist science-based fisheries management.

—Toadfishes (Batrachoidiformes) are benthic fishes often burying in the sand or under rocks that occur worldwide in tropical to temperate marine and brackish waters. The Batrachoididae, the...

Hollardia hollardi (Reticulate Spikefish) is reported from two specimens caught in lobster traps along the southern edge of Georges Bank, far north of its previously known northern distribution from southern Florida, the Bahamas, and Bermuda.

Belone is distinguished from other genera of Belonidae mostly because of its complete cephalic sensory system, presence of gill rakers, vomerine teeth, and the pattern of its dentition. This eastern North Atlantic genus contains two extant species and at least three described fossil species from Lower Oligocene and Upper Miocene formations in Europe. †Belone countermani, sp. nov., a new species of needlefish from the Tortonian Upper Miocene St. Marys Formation of Calvert Cliffs (Maryland, U.S.A.), is described herein based on a well-preserved three-dimensional associated pair of upper and lower jaws. This rostrum represents the only record of this genus in the western North Atlantic Ocean. †Belone countermani is characterized by a unique dental pattern on the dentary. The dentary commissural region is filled with several rows of small accessory teeth (five to seven) that gradually decrease in number of rows; along the symphysial region there is one inner row of conical teeth and one external row ...

Validity of the largest size accounts is not well documented and most published accounts of body colora- tion describe dead specimens lacking scales instead of the color of freshly caught opah. Maximum length is at least 163 cm fork length and maximum weight about 89 kg. The body color of fresh specimens is vermilion with white spots.

Dissection and histological analyses revealed the swimbladder of Hemiramphus far and H. robustus to comprise a matrix of discrete, gas-filled vesicles of 1–6 mm in diameter. The vesicles are not richly vascular and no discrete capillary bed organs were found. The anterior and posterior ends of the swimbladder have asymmetric projections that extend rostrad and caudad, respectively. These projections and some surrounding fatty tissue contain what we term protovesicles, which have thick walls that we infer expand to become the thin-walled vesicles of the main vesicular swimbladder. Dissection of museum specimens of other species of Hemiramphus and Oxyporhamphus convexus confirmed the presence of a vesicular swimbladder. However, examination of museum specimens of other hemiramphids, including O. micropterus, and flyingfishes revealed only a simple sac-like swimbladder. Presence of this unusual swimbladder in two genera within the same family is indicative of a strong synapomorphy that, in conjuncti...

We have previously documented multiple, independent origins of placentas in the fish family Poeciliidae. Here we summarize similar analyses of fishes in the family Zenarchopteridae. This family includes three live-bearing genera. Earlier studies documented the presence of superfetation, or the ability to carry multiple litters of young in different stages of development in the same ovary, in some species in all three genera. There is also one earlier report of matrotrophy, or extensive postfertilization maternal provisioning, in two of these genera. We present detailed life-history data for approximately half of the species in all three genera and combine them with the best available phylogeny to make inferences about the pattern of life-history evolution within this family. Three species of Hemirhamphodon have superfetation but lack matrotrophy. Most species in Nomorhamphus and Dermogenys either lack superfetation and matrotrophy or have both superfetation and matrotrophy. Our phylogenetic analysis shows that matrotrophy may have evolved independently in each genus. In Dermogenys, matrotrophic species produce fewer, larger offspring than nonmatrotrophic species. In Nomorhamphus; matrotrophic species instead produce more and smaller offspring than lecithotrophic species. However, the matrotrophic species in both genera have significantly smaller masses of reproductive tissue relative to their body sizes. All aspects of these results are duplicated in the fish family Poeciliidae. We discuss the possible adaptive significance of matrotrophy in the light of these new results. The two families together present a remarkable opportunity to study the evolution of a complex trait because they contain multiple, independent origins of the trait that often include close relatives that vary in either the presence or absence of the matrotrophy or in the degree to which matrotrophy is developed. These are the raw materials that are required for either an analysis of the adaptive significance of the trait or for studies of the genetic mechanisms that underlie the evolution of the trait.

The 40 life history, myological, and osteological characters that Tibbetts (1992) used in his study of the hemiramphids are evaluated for both saury genera (Cololabis and Scomberesox) to determine if the Scomberesocidae are more closely related to the Zenarchopteridae, to the needlefishes (Belonidae), or to the halfbeaks (Hemiramphidae) and flyingfishes (Exocoetidae). Data were analyzed using PAUP*, and eight equally parsimonious trees were found (70 steps, CI 0.814, RI 0.938). This analysis indicates that sauries are most closely related to needlefishes, supporting the historical concept of the superfamily Scomberesocoidea as a monophyletic assemblage. A caudal displacement of the origin of the retractor dorsalis muscle is a tentative additional synapomorphy for all four saury species. Zenarchopteridae is strongly supported as a valid family sister to the Scomberesocoidea (decay index = 19, bootstrap = 100). Resolution of the internal structure of the Belonidae and the Hemiramphidae requires the identification of additional characters and examination of a greater number of taxa.

To investigate jaw evolution in beloniform fishes, we reconstructed the phylogeny of 54 species using fragments of two nuclear (RAG2 and Tmo-4C4) and two mitochondrial (cytochrome b and 16S rRNA) genes. Our total molecular evidence topology refutes the monophyly of needlefishes (Belonidae) and halfbeaks (Hemiramphidae), but supports the monophyly of flyingfishes (Exocoetidae) and sauries (Scomberesocidae). Flyingfishes are nested within halfbeaks, and sauries are nested within needlefishes. Optimization of jaw characters on the tree reveals a diverse array of evolutionary changes in ontogeny. During their development, needlefishes pass through a "halfbeak" stage that closely resembles the adult condition in the hemiramphid halfbeaks. The reconstruction of jaw transitions falsifies the hypothesis that halfbeaks are paedomorphic derivatives of needlefishes. Instead, halfbeaks make up a basal paraphyletic grade within beloniforms, and the needlefish jaw morphology is relatively derived. The parallel between needlefish ontogeny and beloniform phylogeny is discussed, and clades amenable to future morphological analysis are proposed.

The New World clade of needlefishes (Belonidae) includes species distributed along the Pacific and Atlantic coasts of the Americas and in freshwater basins of Central and South America. Phylogenetic relationships among 13 species of the group were assessed based on data from two nuclear genes (RAG2 and Tmo-4C4), two mitochondrial genes (cytochrome b and 16S rRNA), and a small suite of morphological characters. In general, there was concordance between separate analyses of nuclear and mitochondrial characters, and RAG2 was found to be a particularly useful gene for phylogeny reconstruction. Morphology supported an alternative phylogenetic pattern, but this was probably a result of the small number of characters and the lack of a thorough anatomical survey. The total evidence hypothesis divides the group into two major clades. In one, Pseudotylosurus from freshwater in South America is most closely related to a pair of Strongylura species from the western and eastern Atlantic; in the other, Potamor...

Sequence variation in the mitochondrialCytochrome b (Cytb) gene was assayed infour of six extant Bermuda killifishpopulations, representing two endemic species,to test taxonomic and phylogenetic hypothesesand reconstruct colonization history. Twodivergent (4.6%) haplotypes were detected; oneis identical to the Georgia 2c haplotype ofF. heteroclitus and is fixed in threeeastern populations: Lover's Lake (F.relictus), Mangrove Lake (F. bermudae),and Walsingham Pond. The second is fixed andrestricted to a western population, Evan'sPond. Likelihood and parsimony cytochrome btrees recognize a Bermuda Fundulus / F. heteroclitus clade in which the Evan's Pondhaplotype is basal. Phylogenies and haplotypedivergence indicate at least two Bermudacolonizations, the more recent involvingtransfer of the Georgia 2c haplotype. Enforcing Bermuda killifish monophyly, aspredicted from a single colonization event,does not increase tree length significantly;i.e., the trees also are consistent with asingle colonization. However, divergencebetween the Evan's Pond haplotype and the F. bermudae / F. relictus / Georgia 2chaplotype (4.6%) far exceeds the maximumdivergence among all F. heteroclitus,F. bermudae, and F. heteroclitushaplotypes (1.2%) and argues for independentcolonizations. Alternatively, recentintroduction of F. heteroclitus couldaccount for occurrence of the GA2c haplotype inBermuda but does not explain the presence ofthe genetically divergent Evans' Pondhaplotype. Cytb sequences areuninformative of the taxonomic status ofBermuda endemics, F. bermudae and F.relictus, but support recognition of theEvan's Pond population as an evolutionarilysignificant unit within the F. heteroclitus group.

The population ofScomber from the Red Sea and northern Indian Ocean (gulfs of Aden and Oman) is identified asS. australasicus rather thanS. japonicus based on having 30–33 vs. 26–29 interneural bones under the first and second dorsal fins and the combination of interneural bone counts of 16–20 under the first dorsal fin (vs. 13–16) and first dorsal fin spine counts of 10–13 (vs. 9–10). These are the best morphological characters to distinguish these two species. This change in identification constitutes a major range extension forS. australasicus which was thought to be restricted to the Pacific Ocean and the southeastern Indian Ocean around Western Australia.

DNA barcoding is a method promising fast and accurate identification of animal species based on the sequencing of the mitochondrial c oxidase subunit (COI) gene. In this study, we explore the prospects for DNA barcoding in one particular fish group, the billfishes (suborder Xiphioidei--swordfish, marlins, spearfishes, and sailfish). We sequenced the mitochondrial COI gene from 296 individuals from the 10 currently recognized species of billfishes, and combined these data with a further 57 sequences from previously published projects. We also sequenced the rhodopsin gene from a subset of 72 individuals to allow comparison of mitochondrial results against a nuclear marker. Five of the 10 species are readily distinguishable by COI barcodes. Of the rest, the striped marlin (Kajikia audax) and white marlin (K. albida) show highly similar sequences and are not unambiguously distinguishable by barcodes alone, likewise are the three spearfishes Tetrapturus angustirostris, T. belone, and T. pfluegeri. We discuss the taxonomic status of these species groups in light of our and other data, molecular and morphological.

The jaw morphology of needlefishes (Beloniformes : Belonidae) passes through distinctive ontogenetic stages. When hatched, larvae have short jaws of equal length. The lower jaw first elongates to produce a halfbeak form, then the upper jaw elongates to produce the adult needlenose morphology. Onset and duration of the halfbeak stage vary among belonid species. We tested the hypothesis that heterochronic evolution produced this diversity in jaw morphology

The slender tuna, Allothunnus fallai Serventy 1948, is an epipelagic scombrid with a circumglobal distribution in the Southern Ocean from about 20–50 S (Warashina and Hisada 1972; Collette and Nauen 1983), south to 54 S in the South Pacific (Yatsu 1995), with three exceptions from the North Pacific (Schaefer and Childers 1999). Recently, an adult male, 784-mm fork length (Fig. 1) was taken further south in the South Atlantic, at 53 250S, 64 230W off Tierra del Fuego, Argentina. It was caught while trawling at 167 m on March 12, 2007 by the fishing vessel Tai An. The surface water temperature was 8 C and the salinity 33.59 parts per thousand (ppt). The specimen has been deposited in the fish collection of the Instituto Nacional de Investigacion y Desarrollo Pesquero under number INIDEP 801. Measurements and counts (Table 1) follow the methods of Collette and Chao (1975) and Schaefer and Childers (1999). External characters agree with descriptions given by previous authors (Serventy 1948; Collette and Chao 1975; Collette and Nauen 1983; Schaefer and Childers 1999). The elongate and rounded shape of the body and the lack of body markings (Fig. 1) are characteristic of this species. Fin-ray and especially, gill-raker counts of 74 confirm the identification. Slender tuna make seasonal migrations from subantarctic and transitional waters to subtropical waters, coupled to seasonal geographic shifts in biomass of epipelagic subantarctic zooplankton (Yatsu 1995). Slender tuna appear to spawn in subtropical waters and in the Peru Current, from approximately 20–30 S, October–December at sea-surface temperatures of 17–25 C (Watanabe et al. 1966; Yatsu 1995). Juveniles are principally encountered between 20 and 35 S at surface temperatures ranging from 19 to 24 C. With increasing size, they gradually move into higher latitudes where water temperatures are lower. Distributions of three species of scombrids are concentrated in the Southern Ocean (Warashina and Hisada 1972; Collette and Nauen 1983; Collette et al. 2001): A. fallai; the butterfly mackerel, Gasterochisma melampus Richardson 1845; and the southern bluefin tuna, Thunnus maccoyii (Castelnau 1872). All species of the tribe Thunnini, except for Allothunnus Serventy 1948, have counter-current heat exchanger systems that allow them to retain body heat generated by muscular contractions thus keeping their bodies warmer than the surrounding sea temperature (Graham and Dickson 2000). Gasterochisma Richardson, 1845 has a layer of fat under the scales and has a brain heater that may be involved in keeping them warm. Recently Sepulveda et al. (2007) showed that Allothunnus also has a heater, extraocular muscles that differ from other tunas and serve as a heater organ that can raise cranial temperatures about 4.8 C above ambient sea temperature. Also, the small central vascular plexus of Allothunnus may be capable of conserving metabolic heat generated by continuous swimming to elevate red muscle temperatures (Graham and Dickson 2000) but body temperatures of Allothunnus are as yet unreported. B. B. Collette (&) National Marine Fisheries Systematics Laboratory, Smithsonian Institution, National Museum of Natural History, P.O. Box 37012, Washington, DC 20013-7012, USA e-mail: collettb@si.edu

Three species of remoras--Remora brachyptera (Lowe), Remora osteochir (Cuvier), and Remora remora (Linnaeus)--were collected from 4 species of billfishes--Istiophorus platypterus (Shaw), Makaira nigricans Lacepéde, Tetrapturus albidus Poey, and Tetrapturus pfluegeri Robins and de Sylva--on board a Japanese long-liner Shoyo Maru during her cruise in 2002 across the Atlantic. However, only the marlin sucker (R. osteochir) was found to carry a parasitic copepod, Lepeophtheirus crassus (Wilson and Bere, 1936). Although 12 species of parasitic copepods have been reported from billfishes around the world ocean, none of them is L. crassus. Thus, L. crassus is considered a parasite specific to the marlin sucker.

Phylogenetic relationships among New World and eastern Atlantic species in the belonid genera Strongylura and Tylosurus were hypothesized using 3689 bp of nucleotide sequence; including the entire mitochondrial (mtDNA) ATP synthase 6 and 8 genes; partial cytochrome b ; 12S and 16S ribosomal genes; and introns and exons, 2 and 3 of the nuclear-encoded creatine kinase B gene. Concordant mtDNA and nuclear genealogies permitted well-supported inference of species relationships within Strongylura and Tylosurus , and of the chronology of diversification in the two genera. Our phylogenetic hypothesis permitted an assessment of Rosen’s [Syst. Zool. 24 (1975) 431] model of species diversification across the eastern Atlantic to eastern Pacific marine biogeographic track. The spatial predictions of the Rosen model were generally supported, but not the temporal predictions. Furthermore, long branches leading to terminal Belonidae indicated that many species have persisted for millions of years or that nucleotide substitution rates were elevated for some clades. Though heterogeneity of nucleotide substitution rate was indicated across some belonid lineages, molecular clock estimates were used to hypothesize biogeographic scenarios for Strongylura across the eastern Pacific and Atlantic region. Furthermore, use of a molecular clock indicated; that early diversification among contemporary Strongylura may have been initiated by changes in Atlantic Ocean circulation precipitated by closure of the Tethys Sea; and provided approximate dates for the isolation of the freshwater species on the American continents.

The first standardized, global assessment of these fishes, using Red List criteria, reveals threatened species needing protection.

Publisher Summary This chapter elaborates the systematics of tunas and mackerels (Scombridae). The Scombridae is a family of 1.5 genera and about 50 species of epipelagic marine fishes. They possess many morphological and physiological adaptations that are of great interest to physiologists and evolutionary biologists. Mackerels, Spanish mackerels, bonitos, and tunas form the basis of important commercial and recreational fisheries throughout the tropical and temperate waters of the world. The subfamily Scombrinae is composed of two groups of two tribes. The more primitive mackerels (Scombrini) and Spanish mackerels (Scomberomorini) have a distinct notch in the hypural plate, lack any bony support for the median fleshy caudal peduncle keels, and do not have the penultimate vertebral centra greatly shortened. Scomber japonicus has been considered the most widespread species in the genus, sympatric with S. scombrus in the North Atlantic and with S. australasicus in the northwestern Pacific. Host–parasite relationships of parasitic copepods have been utilized to provide an independent assessment of the relationships of Spanish mackerels of the S. regalis species group.

species group was fully supported, with the eastern Atlantic S. tritor basal to the New World taxa as predicted from the eastern Atlantic/eastern Pacific generalized biogeographic track. Surprisingly, no differences were observed between the mitochondrial genomes of S. regalis and S. maculatus. However nuclear DNA and morphological characters confirm the species status of these two taxa, leading us to posit the introgressive loss of the S. maculatus mtDNA genome following hybridization with S. regalis. Chronological estimates were applied to the phylogenetic topology combining geologic dates for putative vicariant events with molecular distance values. These estimates indicate a pre-isthmian divergence for the western Atlantic S. maculatus, followed by divergence of the common ancestors of the western Atlantic (S. brasiliensis and S. regalis) and eastern Pacific (S. concolor and S. sierra) species resulting from the rise of the Isthmus of Panama and closure of associated seaways.

The structure, origin, and spread of the family Percidae are reviewed briefly, and its characteristics compared with those of other families of freshwater fishes. It is suggested that the percids, essentially riverine, have been restricted in their success in North America by the presence of the Centrachidae. Percids are defined as temperate mesothermal fish, and this physiological characteristic together with osmoregulatory capacity and swimming performance is shown to limit the ranges of the perches. The degree of development of the tapetum lucidum in Stizostedion spp. and of the lateral line in all percids is related to differences in pattern of development, feeding behavior, and habitat. Reproductive, feeding and migratory behaviour are also reviewed. Key words: Percidae, structure, origin, biology, morphology, systematics, migration

Two phyletic lines are present in the Percidae: the Percinae, in which the anteriormost interhaemal bone is much larger than the posterior ones and the anal spines usually are well developed, and the Luciopercinae, in which the interhaemal bones are of uniform size and the anal spines are poorly developed. Parallel evolution has produced in each subfamily small, benthic, rheophilic forms with depressed or terete bodies and reduced or vestigial swimbladders. This differentiation is shown by dividing each subfamily into two tribes. Within the Percinae, the Etheostomatini (Percina, Ammocrypta, and Etheostoma) are interpreted as derivatives of the Percini (Perca, Gymnocephalus [=Acerina], and Percarina). The North American species Perca flavescens is distinguished from the Eurasian species P. fluviatilis and P. schrenki on the basis of the more posterior position of the predorsal bone. In the Luciopercinae, the Romanichthyini (Zingel [=Aspro] and Romanichthys) have evolved from the Luciopercini (Stizostedion [including Lucioperca]). Key words: Percidae, systematics, zoogeography, evolution

Fishes were collected with rotenone from 14 mangrove swamps, 2 in northern Australia, 6 in Papua New Guinea and 6 in Irian Jaya. Over 200 species from 58 families were found. The 12 families found in the most mangrove swamps were Hemiramphidae (13 of 14), Gobiidae (13), Apogonidae (13), Tetraodontidae (10), Blenniidae (10), Lutjanidae (9), Ophichthidae (9), Eleotridae (8), Pomacentridae (8), Toxotidae (8), Ambassidae (8), and Siganidae (7). The number of families collected per mangrove swamp ranged from 9 to 25, the number of species from 12 to 57, and the number of specimens from 59 to 818. Among the most abundant species in some mangroves were two anchovies (Thrissina baelama and Stolephorus commersonii), a cardinalfish (Apogon lateralis), two ambassids (Ambassis interruptus and Priopidichthys gymnocephalus), an atherinid (Atherinomorous endrachtensis), a pomacentrid (Neopomacentrus taeniurus), and a goby (Oligolepis moloanus). Species found in the most mangroves were the archerfish Toxotes jaculator, a blenny Omox biporos and a cardinalfish Apogon lateralis (8 of 14); a cardinalfish Fowleria cf. marmorata, two gobies, Acentrogobius cf. triangularis and Pandaka cf. pygmaea (7); a pipefish Hippichthys spicifer, a third species of cardinalfish Sphaeramia orbicularis, three gobies, Oligolepis moloanus, Parioglossus sp., and Yongeichthys cf. nebulosus, and an elebtrid Eleotris cf. fusca (6). Comparisons are made between the New Guinea mangrove fish fauna and the mangrove fishes in 7 other studies from North Borneo, South Viet Nam, India, Madagascar, Florida, and Puerto Rico.

Zenarchopterus robertsi n. sp. is described from Ovi Creek, a high-gradient tributary of the Kumusi River which drains northeast into the Solomon Sea, Z. alleni n. sp. from a single male taken in the Mamberamo River in Irian Jaya. Both species differ from all other described species of Zenarchopterus in having the fifth and sixth anal rays of the male greatly elongate. Most other species have the sixth or the sixth and seventh rays variously modified. The other two freshwater species of Zenarchopterus known from New Guinea, Z. kampeni (found in the Sepik, Ramu and Mamberamo rivers which drain north) and Z. novaeguineae (found in at least three south-draining rivers, the Lorentz, Fly and Laloki) have the sixth anal ray of males expanded and paddle-shaped. The two new species have more predorsal scales (47-53 in Z. robertsi, 66 in Z. alleni) than do other species of the genus and the predorsal scales are not enlarged but about the same size as adjacent scales. Both new species have many vertebrae, usually 47 or 48 in Z. robertsi, 49 in Z. alleni. They differ in upper jaw length, the upper jaw being longer than wide in Z. alleni, length about equal to width in Z. robertsi. The pectoral fin is much longer than head length in Z. alleni, equal to or shorter than head length in all other species of the genus. There are at least 34 nominal species of Zenarchopterus of which about 17 appear to be valid. Biological notes are included on Z. robertsi. Geographic variation is discussed in Z. novaeguineae. The type-specimens of both Z. kampeni and Z. sepikensis came from the Sepik River and represent the same species, the former being the valid name.

83b. Shark ageing methods and age estiation of scalloped hammerhead, Sphyrna lewini, d dusky, Carc arhinus obscurus, sharks based on ertebral ring counts. NOAA Tech. Rep. NMFS of the spurdog (Squalus acanthias) using tetracycline.J. Mar. Biol. Assoc. U.K. 65:641-651. URIST, M. R., AND K. H. IBSEN. 1963. Chemical reactivity of mineralized tissue with oxytetracycline. Arch. Pathol. 76:484-496.

S. munroi, sp. nov.. is described from northern Australia and southern Papua New Guinea. It has been confused with S. niphonius of the north-western Pacific because both are spotted species with many (19-22) dorsal spines. S. niphonius is unique among the 18 species of the genus in having a straight intestine; S. munroi, like most other species of Scomberomorus, has two loops and three limbs to the intestine. S. munroi has more vertebrae (50-52) than S. niphonius (48-50) and most other species of Australian Scomberomorus (S. commerson 42-46, S. queenslandicus 48-49, S. semifasciatus 44-46), except for S. multiradiatus from Papua New Guinea (55-56). S. munroi has a deeper body and a longer postorbital distance than S. niphonius.

Two phyletic lines are recognized within the Percidae: the Percinae, in which the anteriormost interhaemal bone is much larger than the posterior ones and the anal spines usually are well developed, and the Luciopercinae in which the interhaemal bones are of uniform size and the anal spines are poorly developed. Parallel evolution has produced in each subfamily small, bottom-dwelling forms with depressed or terete bodies and reduced or vestigial swimbladders. This differentiation is shown by dividing each subfamily into two tribes. Within the Percinae, the Etheostomatini (Percina, Ammocrypta, and Etheostoma) are interpreted as derivatives of the Percini (Perca, Gymnocephalus [= Acerina], and Percarina). In the Luciopercinae, the Romanichthyini (Zingel [= Aspro] and Romanichthys) have evolved from the Luciopercini (Stizostedion [including Lucioperca]). A table of vertebral numbers is given.

The number of nominal species and subspecies described per year are compared with the cumulative summary of the number of forms considered valid. The history of darter descriptions is divided into four periods: "Beginnings" (1818-1840); "Golden Era" (1841-1892); "Doldrums" (1893-1931); and "Reawakening" (1932-present). The success of different ichthyologists in describing valid taxa is assessed. The number of specimens per type-series forms a strongly skewed distribution from 42 species based on only the holotype to the 1338 type-specimens of Boleosoma nigrum eulepis. The 25 repositories of the 4863 type-specimens of 185 nominal species of darters are divided into three groups based on the number of primary and secondary types. The present number of valid species and subspecies (139) is predicted to rise to about 160 by the year 2000.