Opsanus dichrostomus, a new toadfish (Teleostei: Batrachoididae) from the western Caribbean Sea and southern Gulf of Mexico

http://deepblue.lib.umich.edu/bitstream/2027.42/57167/1/OP731.pd

Geographic Variation in the Central Pacific Halfbeak, Hyporhamphus acutus (Gunther)

Hyporhamphus acutus (Gunther) is distinguished from other Central Pacific species of Hyporhamphus by its long upper jaw, long anal fin base (longer than dorsal base), and shape of its preorbital lateral line canal. Two subspecies are recognized: Hyporhamphus acutus acutus (Gunther) with fewer vertebrae and fin rays inhabits the chain of islands from Wake Island and the Marshall Islands in the northwest to the Tuamotu Archipelago and Easter Island in the southeast; Hyporhamphus acutus paciftcus (Steindachner) with more vertebrae and fin rays is found in the Hawaiian Islands and at Johnston Island. Hemiramphus furcatus Philippi from Easter Island and Odontorhamphus chancellori Weed from the Cook Islands are placed in the synonymy of Hyporhamphus acutus acutus

Moving Walkways, Escalators, and Elevators

We study a simple geometric model of transportation facility that consists of two points between which the travel speed is high. This elementary definition can model shuttle services, tunnels, bridges, teleportation devices, escalators or moving walkways. The travel time between a pair of points is defined as a time distance, in such a way that a customer uses the transportation facility only if it is helpful. We give algorithms for finding the optimal location of such a transportation facility, where optimality is defined with respect to the maximum travel time between two points in a given set.Comment: 16 pages. Presented at XII Encuentros de Geometria Computacional, Valladolid, Spai

Global Phylogeography Of Mackerels Of The Genus Scomber

Inter- and intraspecific genetic relationships among and within three species of mackerels of the genus Scomber were investigated by restriction site analysis of the whole mitochondrial (mt) DNA genome and direct sequence analysis of the mitochondrial cytochrome b gene. A total of 15 samples, averaging 19 individuals each, were collected from geographically isolated populations throughout the ranges of S. scombrus (two samples), S, australasicus (five samples), and S. japonicus (eight samples). Restriction site analysis with 12 restriction enzymes revealed substantial genetic variation within each species. Sample haplotype diversities ranged from 0.28 to 0.95, and nucleotide sequence diversities from 0.13% to 0.76%. Spatial partitioning of genetic variation was observed in each of the species. Eastern and western North Atlantic samples of S. scombrus exhibited significant heterogeneity in the distribution of mtDNA haplotypes, but no fixed restriction site differences were observed between samples. Similarly, no fixed restriction site differences occurred among samples of S. japonicus in the Atlantic Ocean, although there were significant differences in the distribution of haplotypes among samples. In contrast, samples of S. japonicus from within the Pacific Ocean were characterized by fixed restriction site differences. North and South Pacific samples of S. australasicus were highly divergent, and one of two divergent mtDNA matrilines was restricted to samples from the South Pacific. A 420-bp segment of the cytochrome b gene was sequenced for representatives of each of the major mtDNA lineages identified by restriction site analysis. Scomber scombrus differed from S. australasicus and S. japonicus by more than 11% net nucleotide sequence divergence, considerably greater than the 3.5% sequence divergence between S. australasicus and S. japonicus. Levels of interspecific genetic divergences based on restriction site data were similar in pattern, but were approximately 20% lower in magnitude when based on the cytochrome b sequences. Parsimony analysis and neighbor-joining of restriction site data, and parsimony analysis of cytochrome b sequences showed similar paraphyletic patterns in both S, japonicus and S. australasicus. Levels of divergence among samples of S. japonicus were similar to those between samples of S. australasicus and S. japonicus. Complete partitioning of halpotypes among some samples of S. japonicus that are morphologically distinct suggests that Atlantic and Indo-Pacific populations of S. japonicus may need to be recognized as separate species

Corrected Numbers for fish on Red List

(First paragraph) Kelly Swing gives inaccurate numbers for marine fish species on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. He also mistakenly conflates the scientific process of species assessment for the Red List with the separate political process of IUCN member voting (Nature 494, 314; 2013)

Unstable and Stable Classifications of Scombroid Fishes

Many cladists believe that a classification should strictly reflect a cladistic hypothesis. Consequently, they propose classifications that often differ markedly from existing ones and are potentially unstable due to phylogenetic uncertainty. This is problematic for economically or ecologically important organisms since changing classifications can cause confusion in their management as resources. The classification of the 44 genera of scombroid fishes (the mackerels, tunas, billfishes, and their relatives) illustrates this problem of instability. Previous cladistic analyses and analyses presented in this paper, using different data sets, result in many different cladistic hypotheses. In addition, the inferred cladograms are unstable because of different plausible interpretations of character coding. A slight change in coding of a single character, the presence of splint-like gill rakers, changes cladistic relationships substantially. These many alternative cladistic hypotheses for scombroids can be converted into various cladistic classifications, all of which are substantially different from the classification currently in use. In contrast, a quantitative evolutionary systematic method produces a classification that is unchanged despite variations in the cladistic hypothesis. The evolutionary classification has the advantage of being consistent with the classification currently in use, it summarizes anagenetic information, and it can be considered a new form of cladistic classification since a cladistic hypothesis can-be unequivocally retrieved from an annotated form of the classification