An official website of the United States government
Synopsis Antarctic krill (Euphausia superba) larval production and overwinter survival drive recruitment variability, which in turn determines abundance trends. The Antarctic Peninsula has been described as a recruitment hot spot and as a potentially important source region for larval and juvenile krill dispersal. However, there has been no analysis to spatially resolve regional-scale krill population dynamics across life stages. We assessed spatiotemporal patterns in krill demography using two decades of austral summer data collected along the North and West Antarctic Peninsula since 1993. We identified persistent spatial segregation in the summer distribution of euphausiid larvae (E. superba plus other species), which were concentrated in oceanic waters along the continental slope, and E. superba recruits, which were concentrated in shelf and coastal waters. Mature females of E. superba were more abundant over the continental shelf than the slope or coast. Euphausiid larval abundance was relatively localized and weakly correlated between the North and West Antarctic Peninsula, while E. superba recruitment was generally synchronized throughout the entire region. Euphausiid larval abundance along the West Antarctic Peninsula slope explained E. superba recruitment in shelf and coastal waters the next year. Given the localized nature of krill productivity, it is critical to evaluate the connectivity between upstream and downstream areas of the Antarctic Peninsula and beyond. Krill fishery catch distributions and population projections in the context of a changing climate should account for ontogenetic habitat partitioning, regional population connectivity, and highly variable recruitment.
more »
« less
Akarotaxis gouldae, a new species of Antarctic dragonfish (Notothenioidei: Bathydraconidae) from the western Antarctic Peninsula
Bathydraconidae (Notothenioidei) are a group of benthic fishes endemic to the Southern Ocean. Because of their recent evolutionary radiation and limited sampling efforts due to their occurrence in remote regions, their diversity is likely underestimated. Akarotaxis nudiceps, currently the only recognized member of its genus, is an especially poorly known bathydraconid. Although A. nudiceps has a circumpolar distribution on the Antarctic continental shelf, its deep habitat and rarity limit knowledge of its life history and biology. Using a combination of morphological and genetic analyses, we identified an undescribed species of this genus, herein named Akarotaxis gouldae sp. nov. (Banded Dragonfish). The separation of this species was initially identified from archived larval specimens, highlighting the importance of early life stage taxonomy and natural history collections. All currently known adult and larval A. gouldae sp. nov. specimens have been collected from a restricted ~400 km coastal section of the western Antarctic Peninsula, although this is possibly due to sampling bias. This region is targeted by the epipelagic Antarctic krill fishery, which could potentially capture larval fishes as bycatch. Due to the extremely low fecundity of A. gouldae sp. nov. and near-surface occurrence of larvae, we suggest the growing Antarctic krill fishery could negatively impact this speces.
more »
« less
- PAR ID:
- 10611348
- Publisher / Repository:
- Zoological Taxonomists Society
- Date Published:
- Journal Name:
- Zootaxa
- Volume:
- 5501
- Issue:
- 2
- ISSN:
- 1175-5326
- Page Range / eLocation ID:
- 265 to 290
- Subject(s) / Keyword(s):
- Fish, West Antarctic Peninsula
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Embrithopoda is an extinct clade of herbivorous placental mammals belonging to the afrotherian subclade Paenungulata. Early in their evolutionary history, embrithopods colonized the insular terrane of Balkanatolia, presumably via dispersal across the Tethyan marine barrier that separated Africa from Eurasia during the early Cenozoic. Here we report new embrithopods from the early Eocene locality of Çamili Mezra, Çiçekdaği Basin, central Anatolia, which document the early co-occurrence of two sympatric species of embrithopods, including Crivadiatherium sevketseni sp. nov. and Crivadiatherium sahini sp. nov. The genus Crivadiatherium, otherwise known only from the late Eocene of Romania, is reported for the first time in Anatolia. Hypsamasia seni from the middle Eocene of north-central Anatolia is interpreted as a nomen dubium. Embrithopod specimens previously described as Palaeoamasia sp. nov. from the Eocene-Oligocene transition of the Boyabat Basin in northern Anatolia are identified as a new genus and species, Axainamasia sandersi. The embrithopod fauna of Çamili Mezra indicates that this clade experienced at least a modest adaptive radiation after successfully colonizing Balkanatolia. The Balkanatolian record of embrithopod evolution contrasts with the evolutionary history of this clade in its native Africa, where sympatric embrithopod taxa have never been documented.more » « less
-
The Antarctic marine environment, although rich in life, is predicted to experience rapid and significant effects from climate change. Despite a revolution in the approaches used to document biodiversity, less than one percent of Antarctic marine invertebrates are represented by DNA barcodes and we are at risk of losing biodiversity before discovery. The ease of sequencing mitochondrial DNA barcodes has promoted this relatively ‘universal’ species identification system across most metazoan phyla and barcode datasets are currently readily used for exploring questions of species-level taxonomy. Here we present the most well-sampled phylogeny of the direct-developing, Southern Ocean nudibranch mollusc, Doris kerguelenensis to date. This study sampled over 1000 new Doris kerguelenensis specimens spanning the Southern Ocean and sequenced the mitochondrial COI gene. Results of a maximum likelihood phylogeny and multiple subsequent species delimitation analyses identified 27 new species in this complex (now 59 in total). Using rarefaction techniques, we infer more species are yet to be discovered. Some species were only collected from southern South America or the sub-Antarctic islands, while at least four species were found spanning the Polar Front. This is contrary to dispersal predictions for species without a larval stage such as Doris kerguelenensis. Our work demonstrates the value of increasing geographic scope in sampling and highlights what could be lost given the current global biodiversity crisis.more » « less
-
Melanesian blindsnakes of the genus Gerrhopilus have been little collected or researched. I examined specimens assigned in museums to Gerrhopilus inornatus and found considerable morphological diversity among them that indicates the presence of multiple species. I redescribe G. inornatus (Boulenger) based on the holotype and one additional specimen, and I describe six new species among specimens currently subsumed under that name from Papua New Guinea: Gerrhopilus flavinotatus sp. nov., Gerrhopilus lorealis sp. nov., Gerrhopilus papuanorum sp. nov., Gerrhopilus polyadenus sp. nov., Gerrhopilus slapcinskyi sp. nov., and Gerrhopilus wallachi sp. nov. Each species is currently known from only 1–3 specimens, and all but two are known only from single localities. In addition to traditional information on scale counts, habitus, and color patterns, I found the numbers and distributions of epidermal glands among the head shields to be especially useful for discriminating among species. The number of recognized Melanesian Gerrhopilus has increased tremendously in recent years, but the region has been poorly sampled for these snakes, and it is to be expected that additional species will be identified at such time as surveys can more effectively target these cryptic snakes.more » « less
-
The genusPseudogymnoascusincludes several species frequently isolated from extreme environments worldwide, including cold environments such as Antarctica. This study describes three new species ofPseudogymnoascus—P. russussp. nov.,P. irelandiaesp. nov., andP. ramosussp. nov.—isolated from Antarctic soils. These species represent the firstPseudogymnoascustaxa to be formally described from Antarctic soil samples, expanding our understanding of fungal biodiversity in this extreme environment. Microscopic descriptions of asexual structures from living cultures, along with measurements of cultural characteristics and growth on various media types at different temperatures, identify three distinct new species. In addition, phylogenetic analyses based on five gene regions (ITS, LSU, MCM7, RPB2, TEF1) and whole-genome proteomes place these new species within three distinct previously described clades:P. irelandiaein clade K,P. ramosusin clade Q, andP. russusin clade B. These results provide further evidence of the extensive undescribed diversity ofPseudogymnoascusin high-latitude soils. This study contributes to the growing body of knowledge on Antarctic mycology and the broader ecology of psychrophilic and psychrotolerant fungi.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.11646/zootaxa.5501.2.3
