Fish otoliths from the middle Miocene Pebas Formation of the Peruvian Amazon

A small assemblage of 22 otoliths was identified from the historical collection of Bluntschli and Peyer gathered in 1912 on the Itaya riverbank at Iquitos, Peru (Amazonia), from the Pebas Formation. The Pebas Mega-Wetland System in western Amazonia during the Miocene represented a unique, albeit short-lived, biotope characterized by a pronounced endemic evolution with gigantism in some vertebrate groups (e.g., turtles, crocodylians). Thus far, fishes have mainly been recorded based on isolated skeletal remains and teeth. Here, we describe the first well-preserved otolith assemblage from the Pebas Formation. This otolith assemblage adds a new facet to the fauna by complementing the skeletal bony fish data, primarily with species of the Sciaenidae and, to a lesser extent, Ariidae and Cichlidae. The sciaenids and ariids indicate that migration must have occurred between the marginal marine environments to the north and the Pebas Wetland System. The otoliths also indicate the likelihood of endemic developments of adapted marine immigrants to the Pebas Wetland System, some of which have become extinct (Pogonias, Umbrina), while others now represent typical South American freshwater fish groups (Plagioscion). Six new species are described based on otoliths, one in the Cichlidae—Cichlasoma bluntschlii n. sp., one in the Ariidae—Cantarius ohei n. sp., and four in the Sciaenidae—Pebasciaena amazoniensis n. gen. et n. sp., Plagioscion peyeri n. sp., Pogonias tetragonus n. sp. and Umbrina pachaula n. sp

Fish remains, mostly otoliths, from the non-marine early Miocene of Otago, New Zealand

Fish remains described from the early Miocene lacustrine Bannockburn Formation of Central Otago, New Zealand, consist of several thousand otoliths and one skeleton plus another disintegrated skull. One species, Mataichthys bictenatus Schwarzhans, Scofield, Tennyson, and T. Worthy gen. et sp. nov., an eleotrid, is established on a skeleton with otoliths in situ. The soft embedding rock and delicate, three−dimensionally preserved fish bones were studied by CT−scanning technology rather than physical preparation, except where needed to extract the otolith. Fourteen species of fishes are described, 12 new to science and two in open nomenclature, representing the families Galaxiidae (Galaxias angustiventris, G. bobmcdowalli, G. brevicauda, G. papilionis, G. parvirostris, G. tabidus), Retropinnidae (Prototroctes modestus, P. vertex), and Eleotridae (Mataichthys bictenatus, M. procerus, M. rhinoceros, M. taurinus). These findings prove that most of the current endemic New Zealand/southern Australia freshwater fish fauna was firmly established in New Zealand as early as 19–16 Ma ago. Most fish species indicate the presence of large fishes, in some cases larger than Recent species of related taxa, for instance in the eleotrid genus Mataichthys when compared to the extant Gobiomorphus. The finding of a few otoliths from marine fishes corroborates the age determination of the Bannockburn Formation as the Altonian stage of the New Zealand marine Tertiary stratigraphy.Werner Schwarzhans, R. Paul Scofield, Alan J.D. Tennyson, Jennifer P. Worthy, and Trevor H. Worth

A new, large-bodied omnivorous bat (Noctilionoidea: Mystacinidae) reveals lost morphological and ecological diversity since the Miocene in New Zealand

A new genus and species of fossil bat is described from New Zealand's only pre-Pleistocene Cenozoic terrestrial fauna, the early Miocene St Bathans Fauna of Central Otago, South Island. Bayesian total evidence phylogenetic analysis places this new Southern Hemisphere taxon among the burrowing bats (mystacinids) of New Zealand and Australia, although its lower dentition also resembles Africa's endemic sucker-footed bats (myzopodids). As the first new bat genus to be added to New Zealand's fauna in more than 150 years, it provides new insight into the original diversity of chiropterans in Australasia. It also underscores the significant decline in morphological diversity that has taken place in the highly distinctive, semi-terrestrial bat family Mystacinidae since the Miocene. This bat was relatively large, with an estimated body mass of ~40 g, and its dentition suggests it had an omnivorous diet. Its striking dental autapomorphies, including development of a large hypocone, signal a shift of diet compared with other mystacinids, and may provide evidence of an adaptive radiation in feeding strategy in this group of noctilionoid bats

Multicopy plasmid integration in Komagataella phaffii mediated by a defective auxotrophic marker

Background: A commonly used approach to improve recombinant protein production is to increase the levels of expression by providing extra-copies of a heterologous gene. In Komagataella phaffii (Pichia pastoris) this is usually accomplished by transforming cells with an expression vector carrying a drug resistance marker following a screening for multicopy clones on plates with increasingly higher concentrations of an antibiotic. Alternatively, defective auxotrophic markers can be used for the same purpose. These markers are generally transcriptionally impaired genes lacking most of the promoter region. Among the defective markers commonly used in Saccharomyces cerevisiae is leu2-d, an allele of LEU2 which is involved in leucine metabolism. Cells transformed with this marker can recover prototrophy when they carry multiple copies of leu2-d in order to compensate the poor transcription from this defective allele. Results: A K. phaffii strain auxotrophic for leucine (M12) was constructed by disrupting endogenous LEU2. The resulting strain was successfully transformed with a vector carrying leu2-d and an EGFP (enhanced green fluorescent protein) reporter gene. Vector copy numbers were determined from selected clones which grew to different colony sizes on transformation plates. A direct correlation was observed between colony size, number of integrated vectors and EGFP production. By using this approach we were able to isolate genetically stable clones bearing as many as 20 integrated copies of the vector and with no significant effects on cell growth. Conclusions: In this work we have successfully developed a genetic system based on a defective auxotrophic which can be applied to improve heterologous protein production in K. phaffii. The system comprises a K. phaffii leu2 strain and an expression vector carrying the defective leu2-d marker which allowed the isolation of multicopy clones after a single transformation step. Because a linear correlation was observed between copy number and heterologous protein production, this system may provide a simple approach to improve recombinant protein productivity in K. phaffii

IMPROVED DETERMINATION OF THE Na−ArX2ΣNa-Ar X^{2}\Sigma INTERACTION POTENTIAL FROM LASERSPECTROSCOPY

$^{a}$ G. Aepfelbach et al. Chem. Phys. Lett. 96 (1983) p. 311 $^{b}$ F. Bokelmann and D. Zimmermann, J. Chem. Phys. 104 (1996) p. 923Author Institution: Fachbereich Physik, Technische Universit\""{a}t BerlinIn a previous laserspectroscopic study of the $A^{2}\Pi \leftarrow X^{2}\Sigma$ transition of NaAr five vibrational levels $v = 0\ldots4$ of the $X^{2}\Sigma$ state have been $observed^{a}$. Recently, we have performed an improved high-resolution investigation of this transition yielding experimental information on two more vibrational levels $v = 5$ and $6. 135$ absorption lines have been observed starting from $v = 5$ and leading to $v' = 6\ldots 8$ of $A^{2}\Pi$. Only a few lines connecting $v = 6$ with $v' = 5\ldots 7$ could be detected. Therefore the assignment of rotational quantum numbers is very tentative in this case. Our preliminary results for the spectroscopic parameters of these levels are (in units of $cm^{-1}$) $$\begin{array}{cccc} & T_{v}-T_{o}& 10^{2}B_{v}&10^{5}D_{v}\\ v=5&34.22(10)&1.72(2)&2.3(2)\\v=6&35.09(20)&0.52(4)&---\end{array}$$ The $X^{2}\Sigma$ interaction potential has been determined in form of an analytical HFD function using our standard method of $approach^{b}$. In addition, the spectral distribution of the fluorescence $A\leftarrow X$ has been recorded showing the well-known reflection structure and allowing a determination of the repulsive part of the $X^{2}\Sigma$ potential

High resolution laser spectroscopy of NaAr: Improved interaction potential for the X

The absorption spectrum of NaAr has been investigated with high resolution using a supersonic beam of molecules and a tunable dye laser. About 3 300 absorption lines due to the transition $A~^2 \Pi~\leftarrow ~X$ and $B~^2 \Sigma ~ \leftarrow ~X$ have been observed. In addition, we observed the spectral distribution of the fluorescence for a particular absorption line. From all experimental data the $X~^2 \Sigma^+$ interaction potential has been deduced in a fully quantum–mechanical method of approach. The potential is given in terms of an analytical Hartree-Fock-Dispersion function. For the equilibrium parameters of the X state we get $R_{\rm e}=~5.01(1)$ Å and $D_{\rm e}=41.6(2)~{\rm cm}^{-1}$