237 research outputs found
A fast GNU method to draw accurate scientific illustrations for taxonomy
Nowadays only digital figures are accepted by the most important journals of taxonomy. These may be produced by scanning conventional drawings, made with high precision technical ink-pens, which normally use capillary cartridge and various line widths. Digital drawing techniques that use vector graphics, have already been described in literature to support scientists in drawing figures and plates for scientific illustrations; these techniques use many different software and hardware devices. The present work gives step-by-step instructions on how to make accurate line drawings with a new procedure that uses bitmap graphics with the GNU Image Manipulation Program (GIMP). This method is noteworthy: it is very accurate, producing detailed lines at the highest resolution; the raster lines appear as realistic ink-made drawings; it is faster than the traditional way of making illustrations; everyone can use this simple technique; this method is completely free as it does not use expensive and licensed software and it can be used with different operating systems. The method has been developed drawing figures of terrestrial isopods and some examples are here given
Using ancient DNA analysis and radiocarbon dating to determine the provenance of an unusual whaling artifact
Natural history collections provide a critical temporal view of past biodiversity and are instrumental in the study of extinct populations. However, the value of historical specimens relies on correct species identification, collection date and collection locality. The Australian National Maritime Museum (ANMM) holds an unusual artifact – an electric lamp made from a dried whale penis – with unknown age, species-of-origin and collection locality. We used ancient DNA methods to generate a partial mitochondrial DNA (mtDNA) genome sequence to establish the identity and provenance of the whale, and accelerator mass spectrometry (AMS) radiocarbon dating to determine the approximate year of death. Mitochondrial DNA sequences from the 16S rRNA gene and the control region indicate that the specimen belonged to a sperm whale (Physeter macrocephalus) and a modern radiocarbon age suggests it was collected post-1950s. We were unable to determine the collection locality of the whale due to the very broad geographic distribution of its mtDNA haplotype. Our results suggest the specimen was possibly collected as a souvenir during post-war whaling, where nearly 30,000 male sperm whales were killed annually. This study supports and extends previous research that applies ancient DNA and radiocarbon dating techniques to enhance the value of natural history collections, by identifying the species-of-origin and age of historical specimens.Caitlin Mudge, Rebecca Dallwitz, Bastien Llamas and Jeremy J. Austi
Cirolana songkhla, a new species of brackish-water cirolanid isopod (Crustacea, Isopoda, Cirolanidae) from the lower Gulf of Thailand
Cirolana songkhla sp. n. was collected from brackish-water habitats including lagoons and estuaries in the coastal zone of the lower Gulf of Thailand. C. songkhla sp. n. is described and fully illustrated; C. songkhla sp. n. can be recognized by the presence of abundant chromatophores dorsally, lack of ornamentation on the posterior pereonites, pleonites and pleotelson, the number of robust setae on the uropodal and pleotelson margins (uropod exopod lateral margin with 12–14 RS, mesial margin with 5–8 RS; endopod lateral margin with 8–10 RS, mesial margin with 11–13 RS; pleotelson with 12–15 RS) and lack of setae on the endopods of pleopods 3–5. A dichotomous key of brackish Cirolana species in Thailand is given
Status of Exosphaeroma amplicauda (Stimpson, 1857), E-aphrodita (Boone, 1923) and description of three new species (Crustacea, Isopoda, Sphaeromatidae) from the north-eastern Pacific
Exosphaeroma amplicauda (Stimpson, 1857) from the west coast of North America is reviewed and redescribed and revealed to be a group of closely related species. A neotype is designated and the species redescribed based on the neotype and topotypic specimens. Exosphaeroma amplicauda is known only from the coast of California, at Marin, Sonoma and San Mateo Counties. E. aphrodita (Boone, 1923), type locality La Jolla, California and previously considered nomen dubium is taken out of synonymy and re-validated. A further three species: E. paydenae sp. n., E. russellhansoni sp. n., and E. pentcheffi sp. n. are described herein. Sphaeroma octonctum Richardson, 1899 is placed into junior synonymy with Exosphaeroma amplicauda. A key to the Pacific West Coast Exosphaeroma is provided
- …