Faculty Opinions recommendation of Dark pigmentation limits thermal niche position in birds.

The physiology and behaviour of fish are strongly affected by ambient water temperature. Physiological traits related to metabolism, such as aerobic scope (AS), can be measured across temperature gradients and the resulting performance curve reflects the thermal niche that fish can occupy. We measured AS of Westslope Cutthroat Trout (Oncorhynchus clarkii lewisi) at 5, 10, 15, 20, and 22°C and compared temperature preference (Tpref) of the species to non-native Brook Trout, Brown Trout, and Rainbow Trout. Intermittent-flow respirometry experiments demonstrated that metabolic performance of Westslope Cutthroat Trout was optimal at ~15 °C and decreased substantially beyond this temperature, until lethal temperatures at ~25 °C. Adjusted preferred temperatures across species (Tpref) were comparatively high, ranging from 17.8-19.9 °C, with the highest Tpref observed for Westslope Cutthroat Trout. Results suggest that although Westslope Cutthroat Trout is considered a cold-water species, they do not prefer or perform as well in cold water (≤ 10°C), thus, can occupy a warmer thermal niche than previously thought. The metabolic performance curve (AS) can be used to develop species‐specific thermal criteria to delineate important thermal habitats and guide conservation and recovery actions for Westslope Cutthroat Trout.

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New species of Cyphocharax (Characiformes: Curimatidae) from the upper rio Negro, Amazon basin

Neotropical Ichthyology ◽

10.1590/1982-0224-20130153 ◽

2014 ◽

Vol 12 (2) ◽

pp. 327-332 ◽

Cited By ~ 7

Author(s):

Bruno F. Melo ◽

Richard P. Vari

Keyword(s):

New Species ◽

Amazon Basin ◽

Caudal Peduncle ◽

Caudal Fin ◽

Rio Negro ◽

Fin Rays ◽

Dark Pigmentation ◽

Northern Brazil ◽

Adipose Fin ◽

A New Species

A new species of Cyphocharax, Curimatidae, apparently endemic to the blackwater upper rio Negro of the Amazon basin in northern Brazil, is described.The new species is readily distinguished from its congeners by the presence of a distinctly longitudinally elongate, posteriorly vertically expanding patch of dark pigmentation along the midlateral surface of the caudal peduncle, with the patch extending from the base of the middle caudal-fin rays anteriorly past the vertical through the posterior terminus of the adipose fin. The new species additionally differs from all congeners in details of body and fin pigmentation and meristic and morphometric ratios. Evidence for the assignment of the species to Cyphocharax and the occurrence of other species of the Curimatidae apparently endemic to the upper rio Negro catchment is discussed.

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Thermal niche conservatism in an environmental gradient in the spider Sicarius thomisoides (Araneae: Sicariidae): Implications for microhabitat selection

Journal of Thermal Biology ◽

10.1016/j.jtherbio.2018.10.018 ◽

2018 ◽

Vol 78 ◽

pp. 298-303 ◽

Cited By ~ 4

Author(s):

A. Taucare-Rios ◽

C. Veloso ◽

R.O. Bustamante

Keyword(s):

Environmental Gradient ◽

Niche Conservatism ◽

Microhabitat Selection ◽

Thermal Niche

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Two new species of Cossura (Cossuridae, Annelida) from the terminal lobes of the Congo River deep-sea fan

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315417000066 ◽

2017 ◽

Vol 97 (5) ◽

pp. 881-888

Author(s):

Anna Zhadan

Keyword(s):

New Species ◽

Deep Sea ◽

Anterior Margin ◽

Posterior Part ◽

Entire Body ◽

Congo River ◽

Two New Species ◽

Dark Pigmentation ◽

Sea Fan ◽

Scanning Electron

Two new species of Cossura Webster & Benedict, 1887 were found in material collected during sampling from the terminal lobes of the Congo deep-sea fan. They were described using light and scanning electron microscopy. Cossura platypus sp. nov. has 15–17 thoracic chaetigers, a prostomium longer than it is wide, with a widely rounded anterior margin, an abruptly expanded posterior prostomial ring the same length as the peristomium, without a mid-ventral notch, a branchial filament attached to the midlength of chaetiger 3, and a pygidium with three anal cirri. Cossura platypus sp. nov. is similar to C. brunnea Fauchald, 1972 but differs in the shape of the prostomium, which is widely rounded anteriorly in C. platypus sp. nov. and is broadly triangular in C. brunnea; furthermore, C. platypus sp. nov.is uniformly pale, whereas C. brunnea has dark pigmentation. Cossura candida Hartman, 1955 differs from C. platypus sp. nov. in the conical shape of the prostomium and 24–35 thoracic chaetigers. Cossura flabelligera sp. nov. has 16–19 thoracic chaetigers, a conical prostomium, and a branchial filament arising from the posterior part of chaetiger 2; the entire body, including the chaetae, is covered by a thick mucous sheath similar to the tunic of flabelligerids. Cossura flabelligera sp. nov. resembles C. longocirrata Webster & Benedict, 1887 in the position of the branchial filament, the shape of the prostomium, and the number of thoracic chaetigers; it differs in having a thick mucous sheath. This character seems to be unique for the Cossuridae.

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Do Differences in Latitudinal Distributions of Species and Organelle Haplotypes Reflect Thermal Reaction Norms Within the Emiliania/Gephyrocapsa Complex?

Frontiers in Marine Science ◽

10.3389/fmars.2021.785763 ◽

2021 ◽

Vol 8 ◽

Author(s):

Peter von Dassow ◽

Paula Valentina Muñoz Farías ◽

Sarah Pinon ◽

Esther Velasco-Senovilla ◽

Simon Anguita-Salinas

Keyword(s):

Local Adaptation ◽

Coastal Upwelling ◽

Environmental Gradients ◽

Reaction Norm ◽

Emiliania Huxleyi ◽

Thermal Reaction ◽

Reaction Norms ◽

Thermal Niche ◽

Significant Difference ◽

The Difference

The cosmopolitan phytoplankter Emiliania huxleyi contrasts with its closest relatives that are restricted to narrower latitudinal bands, making it interesting for exploring how alternative outcomes in phytoplankton range distributions arise. Mitochondrial and chloroplast haplogroups within E. huxleyi are shared with their closest relatives: Some E. huxleyi share organelle haplogroups with Gephyrocapsa parvula and G. ericsonii which inhabit lower latitudes, while other E. huxleyi share organelle haplogroups with G. muellerae, which inhabit high latitudes. We investigated whether the phylogeny of E. huxleyi organelles reflects environmental gradients, focusing on the Southeast Pacific where the different haplogroups and species co-occur. There was a high congruence between mitochondrial and chloroplast haplogroups within E. huxleyi. Haplogroup II of E. huxleyi is negatively associated with cooler less saline waters, compared to haplogroup I, both when analyzed globally and across temporal variability at the small special scale of a center of coastal upwelling at 30° S. A new mitochondrial haplogroup Ib detected in coastal Chile was associated with warmer waters. In an experiment focused on inter-species comparisons, laboratory-determined thermal reaction norms were consistent with latitudinal/thermal distributions of species, with G. oceanica exhibiting warm thermal optima and tolerance and G. muellerae exhibiting cooler thermal optima and tolerances. Emiliania huxleyi haplogroups I and II tended to exhibit a wider thermal niche compared to the other Gephyrocapsa, but no differences among haplogroups within E. huxleyi were found. A second experiment, controlling for local adaptation and time in culture, found a significant difference between E. huxleyi haplogroups. The difference between I and II was of the expected sign, but not the difference between I and Ib. The differences were small (≤1°C) compared to differences reported previously within E. huxleyi by local adaptation and even in-culture evolution. Haplogroup Ib showed a narrower thermal niche. The cosmopolitanism of E. huxleyi might result from both wide-spread generalist phenotypes and specialist phenotypes, as well as a capacity for local adaptation. Thermal reaction norm differences can well explain the species distributions but poorly explain distributions among mitochondrial haplogroups within E. huxleyi. Perhaps organelle haplogroup distributions reflect historical rather than selective processes.

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