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Trinajstic K, Long J, Sanchez S, Boisvert CA, Snitting D, Tafforeau P, Dupret V, Clement AM, Currie PD, Roelofs B, Bevitt JJ, Lee MSY, Ahlberg PE. Response to comment on "Exceptional preservation of organs in Devonian placoderms from the Gogo largerstätte". Science 2023; 380:eadg3748. [PMID: 37167391 DOI: 10.1126/science.adg3748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Jensen et al. (1) question evidence presented of a chambered heart within placoderms, citing its small size and apparently ventral atrium. However, they fail to note the belly-up orientation of the placoderm within one nodule, and the variability of heart morphology within extant taxa. Thus, we remain confident in our interpretation of the mineralized organ as the heart.
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Affiliation(s)
- Kate Trinajstic
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, 6102, WA, Australia
- Western Australian Museum, 49 Kew Street, Welshpool, 6106, Western Australia, Australia
| | - John Long
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide 5001, South Australia, Australia
- Museum Victoria, PO Box 666, Melbourne, Victoria, Australia 3001
| | - Sophie Sanchez
- Department of Organismal Biology, Evolutionary Biology Center, Uppsala University, Norbyvägen 18A, 75236 Uppsala, Sweden
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Catherine A Boisvert
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, 6102, WA, Australia
| | - Daniel Snitting
- Department of Organismal Biology, Evolutionary Biology Center, Uppsala University, Norbyvägen 18A, 75236 Uppsala, Sweden
| | - Paul Tafforeau
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Vincent Dupret
- Department of Organismal Biology, Evolutionary Biology Center, Uppsala University, Norbyvägen 18A, 75236 Uppsala, Sweden
| | - Alice M Clement
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide 5001, South Australia, Australia
| | - Peter D Currie
- Australian Regenerative Medicine Institute and EMBL Australia Building, Monash University, Clayton, 3800, Victoria, Australia
| | - Brett Roelofs
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, 6102, WA, Australia
| | - Joseph J Bevitt
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, 2234, New South Wales, Australia
| | - Michael S Y Lee
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide 5001, South Australia, Australia
- Earth Sciences Section, South Australian Museum, Adelaide, 5000, South Australia
| | - Per E Ahlberg
- Department of Organismal Biology, Evolutionary Biology Center, Uppsala University, Norbyvägen 18A, 75236 Uppsala, Sweden
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Wootton TP, Sepulveda CA, Wegner NC. Gill morphometrics of the thresher sharks (GenusAlopias): Correlation of gill dimensions with aerobic demand and environmental oxygen. J Morphol 2015; 276:589-600. [DOI: 10.1002/jmor.20369] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 12/17/2014] [Accepted: 01/02/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Thomas P. Wootton
- Center for Marine Biotechnology and Biomedicine; Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego; La Jolla CA 92093
| | | | - Nicholas C. Wegner
- Center for Marine Biotechnology and Biomedicine; Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego; La Jolla CA 92093
- Fisheries Resource Division; Southwest Fisheries Science Center, NOAA Fisheries; La Jolla CA 92037
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Dabruzzi TF, Bennett WA. Hypoxia effects on gill surface area and blood oxygen-carrying capacity of the Atlantic stingray, Dasyatis sabina. FISH PHYSIOLOGY AND BIOCHEMISTRY 2014; 40:1011-1020. [PMID: 24352883 DOI: 10.1007/s10695-013-9901-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 12/13/2013] [Indexed: 06/03/2023]
Abstract
Atlantic stingrays, Dasyatis sabina, are common residents of shallow-water seagrass habitats that experience natural cycles of severe hypoxia during summer months. We hypothesized that stingrays exposed to hypoxic episodes would improve their hypoxia tolerance by increasing branchial surface area and altering blood oxygen-carrying capacity. To this end, we compared critical oxygen minimum, gill morphology, and hemoglobin/hematocrit levels in a control group of Atlantic stingrays held at continuous oxygen saturations of 80-90% (≥5.5 mg/l), to treatment groups exposed to a 7-h hypoxic interval at 55% (~4.0 mg/l), or 30% oxygen saturation (~2.0 mg/l). Stingrays in hypoxic treatment groups significantly improved their hypoxia tolerance. Critical oxygen minimum values fell from 0.7 ± 0.11 mg/l in control fish to 0.4 ± 0.05 and 0.4 ± 0.06 mg/l in the 55 and 30% saturation treatment groups, respectively. Mass-specific gill surface area between control fish and the 30% saturation treatment group increased by 1.7-fold, from 85 to 142 mm(2)/g. Although stingrays did not show an increase in hematocrit or hemoglobin levels, production of more efficient hemoglobin isoforms could not be ruled out. An increase in hypoxia tolerance allows Atlantic stingrays to forage for longer times and across a wide range of hypoxic habitats that are less accessible to predators and competitors.
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Affiliation(s)
- Theresa F Dabruzzi
- Department of Wildlife, Fish and Conservation Biology, University of California, One Shields Avenue, Davis, CA, 95616, USA
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Intraspecific scaling of the resting and maximum metabolic rates of the crucian carp (Carassius auratus). PLoS One 2013; 8:e82837. [PMID: 24376588 PMCID: PMC3869722 DOI: 10.1371/journal.pone.0082837] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 10/29/2013] [Indexed: 11/19/2022] Open
Abstract
The question of how the scaling of metabolic rate with body mass (M) is achieved in animals is unresolved. Here, we tested the cell metabolism hypothesis and the organ size hypothesis by assessing the mass scaling of the resting metabolic rate (RMR), maximum metabolic rate (MMR), erythrocyte size, and the masses of metabolically active organs in the crucian carp (Carassius auratus). The M of the crucian carp ranged from 4.5 to 323.9 g, representing an approximately 72-fold difference. The RMR and MMR increased with M according to the allometric equations RMR = 0.212M (0.776) and MMR = 0.753M (0.785). The scaling exponents for RMR (b r) and MMR (b m) obtained in crucian carp were close to each other. Thus, the factorial aerobic scope remained almost constant with increasing M. Although erythrocyte size was negatively correlated with both mass-specific RMR and absolute RMR adjusted to M, it and all other hematological parameters showed no significant relationship with M. These data demonstrate that the cell metabolism hypothesis does not describe metabolic scaling in the crucian carp, suggesting that erythrocyte size may not represent the general size of other cell types in this fish and the metabolic activity of cells may decrease as fish grows. The mass scaling exponents of active organs was lower than 1 while that of inactive organs was greater than 1, which suggests that the mass scaling of the RMR can be partly due to variance in the proportion of active/inactive organs in crucian carp. Furthermore, our results provide additional evidence supporting the correlation between locomotor capacity and metabolic scaling.
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