Population genetic structure of two water strider species in the Ecuadorian Amazon

1. We used mtDNA sequence variation to estimate population genetic structure between and among water strider populations of Potamobates williamsi and P . sumaco in the Ecuadorian Amazon.
2. Sequencing of the COI mitochondrial gene revealed 16 haplotypes, which were summarised into four haplotype groups. P . williamsi and P . sumaco shared two common and widespread haplotypes.
3. Population structure was moderate and gene flow was low. Both air and river distances were significantly correlated with gene flow and, thus, indicative of isolation by distance.
4. The genetic structure within and among populations of P. williamsi and P. sumaco was probably not influenced by the dynamic tropical lotic system.     

Enigmatic tubes associated with microbial crusts from the Late Jurassic of the Northern Calcareous Alps (Austria): a mutualistic sponge–epibiont consortium?

Irregular tube-shaped microfossils incertae sedis are a typical constituent of Late Jurassic shallow-water reefal carbonates of the Northern Calcareous Alps of Austria and are described in open nomenclature. The enigmatic, polymorphous spar-filled tubes with neither observable external nor internal skeletal elements occur either free within peloidal sediments or mostly fixed to skeletal substrates embedded in microbial crusts including the genera Labes Eliášová, Crescentiella Senowbari-Daryan et al . or Isnella Senowbari-Daryan. The tubes are varied in shape and closely resemble different taxa of sponges. As the microbial crusts preferentially occur associated with these tubiform microfossils, this association is suggested to be non-parasitic and mutualistic. Without the surrounding crusts, the existence of these animals would have been masked or perhaps even totally lost in the fossil record expressing the importance of these findings as a characteristic element in the inventory of Late Jurassic reefal biocoenoses.     

Lost in translation – a history of systematic confusion and comments on the type species of Squalodon and Patriocetus (Cetacea,Odontoceti)

Abstract: The two odontocete taxa Squalodon grateloupii and Patriocetus ehrlichii, both the type species of their respective genera, have been at the centre of a great deal of taxonomic confusion. Originally regarded to be conspecific, these two taxa have been the subject of a bewildering taxonomic debate lasting for more than a century, which recently led to the suggestion to abandon these widely used names and replace S. grateloupii with the similar, yet independently and later proposed name S. gratelupi as the type species of Squalodon. Here, we attempt to summarise the events leading to the current confused situation in the hope of resolving this issue once and for all and argue that the name Squalodon grateloupii, as originally proposed, should be reinstated.     

GABA and Prolonged Spinal Inhibition

TWO explanations have been provided for the relatively long latency and prolonged (often exceeding 100 ms) inhibition of firing of spinal motoneurones which is caused by repetitive impulses produced by electrical or natural stimulation^1–4 in muscle and cutaneous afferent fibres. This prolonged inhibitory process is exemplified by the reduction in the amplitude of monosynaptic excitatory synaptic potentials (EPSPs) and reflexes of extensor motoneurones by tetanic stimulation of group I afferents of flexor motoneurones². In contrast with “direct” inhibition, the prolonged inhibition is not reduced by strychnine but is diminished by Picrotoxin^4,6.     

Integrating morphology and mitochondrial DNA for species delimitation within the spruce budworm (Choristoneura fumiferana) cryptic species complex (Lepidoptera: Tortricidae)

Species in cryptic complexes tend to be very difficult, if not impossible, to identify using morphological characters. One such complex is the spruce budworm (Choristoneura fumiferana Clemens, 1865) species group, an economically important group of Nearctic forest pests. Morphological, ecological, behavioural and genetic characters have been studied to try to understand the taxonomy of this group better, but diagnostic character states differ in frequency rather than being complete replacements between each species. We used mitochondrial DNA (mtDNA), together with a new morphology‐based character system that focuses on forewing colour components, to determine if one or a combination of character sources can be used for species diagnoses within the spruce budworm complex. We characterized 47 forewing morphometric measurements and sequenced a 470 bp region of cytochrome c oxidase I mtDNA for 111 ingroup individuals comprising five taxa within the complex. Larval host association and coloration or adult pheromone attraction were used as the prior method for grouping individuals. Our results showed that linear discriminant analysis of morphometric wing characters gave unique clusters for all species on the first and second canonical axes, except for a partial overlap between C. fumiferana and C. biennis, which are not sympatric in nature. In contrast, mtDNA distinguished C. fumiferana, C. pinus pinus Freeman, 1953 and a group of western species, but the three western species (C. occidentalis Freeman, 1967 , C. biennis Freeman, 1967 and C. lambertiana Busck, 1915) shared mtDNA haplotypes. On the basis of the linear discriminant analysis of the combined character set, this study supports the application of both morphology and mtDNA within a framework of integrative taxonomy as the most accurate method for species identification. Furthermore, it demonstrates the utility of quantitative colour analysis, which may be particularly helpful for groups in which colour characters are difficult to divide into discrete units due to intergrading hues.