Richard L. Mayden

Diversity, Distribution, and Conservation Status of the Native Freshwater Fishes of the Southern United States

Abstract The Southeastern Fishes Council Technical Advisory Committee reviewed the diversity, distribution, and status of all native freshwater and diadromous fishes across 51 major drainage units of the southern United States. The southern United States supports more native fishes than any area of comparable size on the North American continent north of Mexico, but also has a high proportion of its fishes in need of conservation action. The review included 662 native freshwater and diadromous fishes and 24 marine fishes that are significant components of freshwater ecosystems. Of this total, 560 described, freshwater fish species are documented, and 49 undescribed species are included provisionally pending formal description. Described subspecies (86) are recognized within 43 species, 6 fishes have undescribed subspecies, and 9 others are recognized as complexes of undescribed taxa. Extinct, endangered, threatened, or vulnerable status is recognized for 28% (187 taxa) of southern freshwater and diadromou...

Phylogeny and biodiversity: Conserving our evolutionary legacy

Historical ecological studies provide information about the origins of species in an area and the origins of traits characterizing the interactions between those species and their environment. Incorporating this evolutionary information into conservation policies will broaden the base of options for making effective decisions about the preservation of biodiversity.

Intraspecific phylogeography of Percina evides (Percidae: Etheostomatinae): an additional test of the Central Highlands pre‐Pleistocene vicariance hypothesis

North America exhibits the most diverse freshwater fish fauna among temperate regions of the world. Species diversity is concentrated in the Central Highlands, drained by the Mississippi, Gulf Slope and Atlantic Slope river systems. Previous investigations of Central Highlands biogeography have led to conflicting hypotheses involving dispersal and vicariance to explain the diversity and distribution of the freshwater fish fauna. In this investigation predictions of the Central Highlands pre‐Pleistocene vicariance hypothesis are tested with a phylogeographic analysis of the percid species Percina evides, which is widely distributed in several disjunct areas of the Central Highlands. Phylogenetic analysis of complete gene sequences of mitochondrially encoded cytochrome b recover three phylogroups, with very low levels of sequence polymorphism within groups. The two western phylogroups are monophyletic with respect to the eastern phylogroup. The recovery of two monophyletic lineages with an eastern and western distribution in the disjunct highland areas is a pattern expected from vicariance, but is not predicted by the Central Highlands pre‐Pleistocene vicariance hypothesis. The recovery of very limited mitochondrial DNA polymorphism and lack of phylogeographic structuring across the entire range of the eastern clade, very shallow polymorphism between the disjunct Missouri River and upper Mississippi River populations, and lack of sequence polymorphism in the upper Mississippi River populations, support a hypothesis of dispersal during or following the Pleistocene. The present distribution of P. evides is best explained by both vicariant and dispersal events.

Phylogenetic Relationships of North American Cyprinids and Assessment of Homology of the Open Posterior Myodome

Phylogenetic analyses based on complete nucleotide sequences of mitochondrial 12S and 16S rRNA genes support the existence of three major clades within the North American phoxinins (Teleostei: Cyprinidae): the western clade, the creek chub clade and the open posterior myodome (OPM) clade. Analyses indicated strong support for the OPM clade including, among others, Mylocheilus, Pogonichthys, Tiaroga, and Rhinichthys. These latter taxa do not exhibit an OPM and previously have not been hypothesized to be related to members of the OPM clade. Parsimony analysis resolved relationships among basal members of the OPM clade and provided an opportunity to address homology of the OPM. Two hypotheses of homology of the OPM were included in analyses, with DNA sequence data allowing investigation of homology and evolution of the OPM. The OPM is best treated as a complex character exhibiting phylogenetic and ontogenetic variation. Previous attempts to simplify coding of the character do not result in hypotheses of homology that are congruent with phylogenetic hypotheses based on DNA sequence data.

Phylogenetic Relationships of the Creek Chubs and the Spine‐Fins: an Enigmatic Group of North American Cyprinid Fishes (Actinopterygii: Cyprinidae)

Phylogenetic analyses based on the complete nucleotide sequence of the mitochondrial 12S ribosomal RNA gene were performed for representatives of major North American cyprinid clades. These analyses resolved four monophyletic groups: (1) Western Clade, represented by Acrocheilus and Gila, (2) Creek Chub Clade, represented by Couesius, Hemitremia, Semotilus, and Margariscus, (3) Open Posterior Myodome Clade, represented by Campostoma, Phenacobius, Cyprinella, Notropis, Platygobio, and Rhinichthys, and (4) Plagopterin Clade, represented by Snyderichthys, Lepidomeda, and Meda. The overall results of these analyses refute previous hypotheses of relationships of North American Cyprinidae based on morphological data. Our analyses support recognition of Snyderichthys, formerly considered a subgenus of Gila, and indicate that the Plagopterin Clade is sister to the Creek Chub Clade. Furthermore, this analysis indicates that hypotheses of relationship between plagopterins and other Western taxa are unsupported and the Open Posterior Myodome Clade is a monophyletic group.

Phylogenetics of Scaphirhynchus Based on Mitochondrial DNA Sequences

Abstract Species delineation and taxonomy within the sturgeon genus Scaphirhynchus is controversial. This issue is made more complex by political issues regarding the Alabama sturgeon S. suttkusi and potential hybridization between sympatric shovelnose sturgeon S. platorynchus and pallid sturgeon S. albus. We investigated phylogenetic relationships among species of Scaphirhynchus based on nucleotide sequences for two mitochondrial loci, cytochrome b and the control region (D-loop). White sturgeon Acipenser transmontanus and green sturgeon A. medirostris were used as outgroups. Phylogenetic analyses did not recover monophyletic shovelnose or pallid sturgeon; however, some populations of pallid sturgeon were resolved as sister to the Alabama sturgeon, and one specimen of shovelnose sturgeon was consistently resolved as the sister to all other ingroup taxa. The hierarchical pattern of relationships produced by analysis of mitochondrial DNA is not consistent with that produced by morphological data. It is con...

Aspects of the Life History of the Ozark Madtom, Noturus albater, in Southeastern Missouri (Pisces: Ictaluridae)

Selected aspects of the life history of Noturus albater Taylor were studied from collections and observations made in southeastern Missouri. During the breeding season, there was sexual dimorphism in shape and size of the genital papillae and degree of development of head musculature. The number of mature ova averaged 111.6 in ripe females. Nesting sites were under large rocks where eggs were laid in a pit and guarded by the male. Clutch size averaged ca. 40 eggs; the eggs were 3.5 4.0 mm wide and adhered to each other in a mass. Notropis zonatus, Etheostoma caeruleum and Percina evides were observed eating eggs and young. Under laboratory conditions eggs hatched in 196 hr at 25 C. Prehatchlings (6.0 mm TL) were mostly devoid of melanophores, had a large yolk sac and the maxillary barbels and pectoral fins were beginning to develop. By 7 days, larvae (11.8 mm TL) were well-pigmented, had barbels, fins and most fin rays developed, the yolk sac nearly absorbed and had the appearance and body form essentially like that of an adult. Individuals of both sexes live at least 2+ years. Aquatic Diptera larvae (mostly midges) were the dominant food item of adults.

Systematics and biogeography of snubnose darters, genusEtheostoma (Teleostei: Percidae) from the black warrior river system Alabama

Abstract Members of the Etheostoma chermocki species group, formerly known only as the Warrior snubnose darter, were examined from throughout their ranges for products of 44 presumptive gene loci. Polyallelic loci support the specific recognition of E. chemocki and indicate that E. bellator is actually a composite of three distinct evolutionary species diagnosable on the basis of both fixed allelic products and significant allele frequency differences. Based on other studies, these species are also diagnosable using traditional morphological characteristics. Eheostoma bellator is the most widely distributed species, while the two new species are endemic to the upper Sipsey and Locust forks of the Black Warrior River system. Phylogenetic evaluation of 30 variable loci and all possible bifurcating trees indicate that the E. chermocki species group is not a monophyletic assemblage. Rather, some species of the group are more closely related to E. simoterum and E. ramseyi in the Tennessee and Alabama river drainages, respectively. Diversification within the Etheostoma chemrocki species group was probably associated with the complex break-up of the Appalachian River System, once connecting the upper Tennessee River and rivers of the current Mobile Basin, and drainage exchanges between the Locust Fork of the Black Warrior River and the adjacent Cahaba or Coosa rivers.

Status of the federally endangered Alabama cavefish, Speoplatyrhinus poulsoni (Amblyopsidae), in Key Cave and surrounding caves, Alabama

Speoplatyrhinus poulsoni, the Alabama cavefish, is a federally endangered stygobitic fish that is restricted to Key Cave in northwestern Alabama. Due to the low abundance of this species and the continuous threats to the caves recharge area, we surveyed Key Cave from 1992 to 1997. Alabama cavefish were present in five different pools and had numbers comparable to previous surveys performed in the 1970s and 1980s. Three different size classes were observed, indicating recruitment is occurring. These data suggest that the population is relatively stable, but future monitoring is recommended. The Alabama cavefish is an endangered species and is extremely difficult to capture, therefore any marking program to accurately estimate the population size is unlikely. A single specimen of Typhlichthys subterraneus was captured in Key Cave. This falsifies the previous assumption that these two species are allopatric. Because of this discovery, we resurveyed seven caves in the area around Key Cave for additional populations of S. poulsoni. These caves had either known populations of T. subterraneus or unidentified cavefish. No additional populations of S. poulsoni were discovered, but further investigation is warranted. The Key Cave National Wildlife Refuge was established in the high recharge area of Key Cave to protect this habitat, yet threats to the groundwater continue from encroaching urbanization.

Origin of Brood Stock and Allozyme Variation in Hatchery-Reared Bonytail, an Endangered North American Cyprinid Fish

Abstract Brood stock of critically endangered bonytail Gila elegans was obtained between 1976 and 1981 from Lake Mohave, Arizona-Nevada, and propagated by artificial means and by natural reproduction in ponds at Dexter National Fish Hatchery, New Mexico. Twenty-four naturally produced F2 individuals were examined electrophoretically for soluble gene products of 45 loci. Six polymorphic loci were identified: aspartate aminotransferase (sAat-A), glucose-6-phosphate isomerase (Gpi-B), and phosphoglucomutase (Pgm-A) from skeletal muscle; esterase (Est-2) from brain; and catalase (Cat-1) and L-iditol dehydrogenase (Iddh-A) from liver. Electromorph distributions at each locus agreed with Hardy–Weinberg expectations. Hatchery bonytail had a lower mean level of heterozygosity than arroyo chub G. orcutti. However, direct-count heterozygosity for bonytail was comparable to mean values reported for other western North American cyprinids. Allozyme variation expressed by hatchery-produced bonytails suggested a genetic...