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Thursday, March 12th, 2015
| Time | Event | ||||||
| 9:31a | [Geology • 2015] Defining the Anthropocene
Time is divided by geologists according to marked shifts in Earth’s state. Recent global environmental changes suggest that Earth may have entered a new human-dominated geological epoch, the Anthropocene. Here we review the historical genesis of the idea and assess anthropogenic signatures in the geological record against the formal requirements for the recognition of a new epoch. The evidence suggests that of the various proposed dates two do appear to conform to the criteria to mark the beginning of the Anthropocene: 1610 and 1964. The formal establishment of an Anthropocene Epoch would mark a fundamental change in the relationship between humans and the Earth system. .......
Simon L. Lews & Mark A. Maslin. 2015. Defining the Anthropocene. Nature. 519: 171–180 doi:10.1038/nature14258 | 10.1038/nature.2015.16739 The Human Epoch: when did it start? | @BobOHara & @GrrlScientist http://gu.com/p/46h8b/stw New study argues the Anthropocene began in 1610 http://news.mongabay.com/2015/0311-hance-a Epoch-defining study pinpoints when humans came to dominate planet Earth http://phy.so/345298759 via @physorg_com | ||||||
| 10:21a | [Paleontology • 2015] Aegirocassis benmoulae • Anomalocaridid Trunk Limb Homology revealed by A Giant Filter-feeder with paired Flaps from the Early Ordovician Fezouata Biota of Morocco
Exceptionally preserved fossils from the Palaeozoic era provide crucial insights into arthropod evolution, with recent discoveries bringing phylogeny and character homology into sharp focus. Integral to such studies are anomalocaridids, a clade of stem arthropods whose remarkable morphology illuminates early arthropod relationships and Cambrian ecology. Although recent work has focused on the anomalocaridid head, the nature of their trunk has been debated widely. Here we describe new anomalocaridid specimens from the Early Ordovician Fezouata Biota of Morocco, which not only show well-preserved head appendages providing key ecological data, but also elucidate the nature of anomalocaridid trunk flaps, resolving their homology with arthropod trunk limbs. The new material shows that each trunk segment bears a separate dorsal and ventral pair of flaps, with a series of setal blades attached at the base of the dorsal flaps. Comparisons with other stem lineage arthropods indicate that anomalocaridid ventral flaps are homologous with lobopodous walking limbs and the endopod of the euarthropod biramous limb, whereas the dorsal flaps and associated setal blades are homologous with the flaps of gilled lobopodians (for example, Kerygmachela kierkegaardi, Pambdelurion whittingtoni) and exites of the ‘Cambrian biramous limb’. This evidence shows that anomalocaridids represent a stage before the fusion of exite and endopod into the ‘Cambrian biramous limb, confirming their basal placement in the euarthropod stem, rather than in the arthropod crown or with cycloneuralian worms. Unlike other anomalocaridids, the Fezouata taxon combines head appendages convergently adapted for filter-feeding with an unprecedented body length exceeding 2 m, indicating a new direction in the feeding ecology of the clade. The evolution of giant filter-feeding anomalocaridids may reflect the establishment of highly developed planktic ecosystems during the Great Ordovician Biodiversification Event.
Phylum Arthropoda von Siebold, 1848 Order Radiodonta Collins, 1996 Family Hurdiidae Vinther, Stein, Longrich & Harper, 2014 Aegirocassis benmoulae gen. et sp. nov. Etymology. Ægir: a giant in Norse mythology and god of the sea; cassis (Latin, helmet): referring to the huge size and elaborate cephalic shield; and in recognition of Mohamed ‘Ou Said’ Ben Moula, who discovered the Fezouata Biota and the specimens described here. Gender feminine.
 Peter Van Roy, Allison C. Daley and Derek E. G. Briggs. 2015. Anomalocaridid Trunk Limb Homology revealed by A Giant Filter-feeder with paired Flaps. Nature. (2015) doi: 10.1038/nature14256 Prehistoric 'Sea Monster' Had More Legs Than Thought http://shar.es/1fvzhZ via @LiveScience YaleNews | Giant sea creature hints at early arthropod evolution http://news.yale.edu/2015/03/11/giant-se | ||||||
| 11:59p | [Herpetology • 2015] Leptolalax pyrrhops • A New Species of Leptolalax (Anura: Megophryidae) from the western Langbian Plateau, southern Vietnam
Abstract We describe a new species of megophryid frog from Loc Bac forest in the western part of the Langbian Plateau in the southern Annamite Mountains, Vietnam. Leptolalax pyrrhops sp. nov. is distinguished from its congeners by a combination of the following morphological attributes: (1) presence of distinct dark brown/black dorsolateral markings, including blackish spots on flanks and dark canthal and/or temporal streaks; (2) rudimentary webbing on toes; (3) tympanum externally distinct; (4) dorsal skin finely shagreened with numerous small tubercles and pustules; (5) medium size for the genus (30.3–33.9 mm in 2 adult males, 30.8–34.3 mm in 7 females); (6) grey-pinkish to dark brownish-violet chest and belly with numerous whitish speckles, also covering the lateral sides of body; (7) ventrolateral glands small, indistinct, do not form a distinct line; (8) pectoral glands comparatively small, comprising 1–3% of adult SVL; (10) iris bicolored, typically bright orange-red in upper two-thirds, fading to silvery green in lower third. The male advertisement call of the new species is also unique among those Leptolalax species for which calls are known, with a single long 'introductory' note, consisting of 5–12 pulses, followed by of 4–5 predominantly single-pulsed notes, and an average dominant frequency of 1.91–2.23 kHz. From the morphologically similar L. applebyi, L. melicus and L. bidoupensis, Leptolalax pyrrhops sp. nov. can be further distinguished by 13.5%, 13.7% and 10.3% sequence divergence at the 16S rRNA mtDNA gene. At present, the new species is known from montane evergreen forest between 800–1100 m elevation. We suggest the species should be considered as Data Deficient following IUCN’s Red List categories. To date our finding represents the southernmost known record of the genus Leptolalax from Vietnam. Keywords: Indochina, Annamite mountains, Southeast Asia, Truong Son, Da Lat Plateau, taxonomy, new species 16S rRNA, advertisement call, microendemism, Leptolalax pyrrhops sp. nov.
Poyarkov, Nikolay A. J., Jodi J. L. Rowley, Svetlana S. Gogoleva, Anna B. Vassilieva, Eduard A. Galoyan & Nikolai L. Orlov. 2015. A New Species of Leptolalax (Anura: Megophryidae) from the western Langbian Plateau, southern Vietnam. Zootaxa. 3931(2): 221–252. DOI: 10.11646/zootaxa.3931.2.3 facebook.com/photo.php?fbid=102052387414 A new, fire-eyed, frog discovered in the forests of Vietnam - @AustMus http://shar.es/1f5sHM |
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