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Triarthrus

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Journal Article

Reassessing growth and mortality estimates for the Ordovician trilobite Triarthrus eatoni Open Access

Daniel Pauly, James D. Holmes
Journal: Paleobiology
Published: 01 February 2023
Paleobiology (2023) 49 (1): 120–130.
DOI: https://doi.org/10.1017/pab.2022.22
...Daniel Pauly; James D. Holmes Abstract A length–frequency sample ( n = 295) from a fossil population of the Ordovician trilobite Triarthrus eatoni Hall, 1838 , assembled and analyzed by J. L. Cisne in 1973 is here reexamined using methods of length–frequency analysis commonly used in fishery...
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Journal Article

PALEOECOLOGY OF THE OLENID TRILOBITE TRIARTHRUS : NEW EVIDENCE FROM BEECHER'S TRILOBITE BED AND OTHER SITES OF PYRITIZATION Available to Purchase

ÚNA C. FARRELL, DEREK E. G. BRIGGS, ROBERT R. GAINES
Journal: PALAIOS
Published: 01 November 2011
PALAIOS (2011) 26 (11): 730–742.
DOI: https://doi.org/10.2110/palo.2011.p11-050r
.... Beds with soft-tissue preservation at the Beecher's Trilobite Bed site in the Frankfort Shale and the Martin Quarry in the Whetstone Gulf Formation (both Ordovician, New York State) are dominated by the olenid Triarthrus. A bed-by-bed analysis of the sedimentology, taphonomy, paleoecology...
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View PDF for article title, PALEOECOLOGY OF THE OLENID TRILOBITE <span class="search-highlight">TRIARTHRUS</span> : NEW EVIDENCE FROM BEECHER&#x27;S TRILOBITE BED AND OTHER SITES OF PYRITIZATION
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Journal Article

Morphometric analysis of ontogeny and allometry of the Middle Ordovician trilobite Triarthrus becki Available to Purchase

Keonho Kim, H. David Sheets, Robert A. Haney, Charles E. Mitchell
Journal: Paleobiology
Published: 01 January 2002
Paleobiology (2002) 28 (3): 364–377.
DOI: https://doi.org/10.1666/0094-8373(2002)028<0364:MAOOAA>2.0.CO;2
... in holaspides is very small relative to that in meraspides. The boundary between meraspis and holaspis in Triarthrus becki appears to correspond to a large change in the rate of ontogenetic change, but neither to a change in the direction of that trajectory nor to a cessation of ontogenetic change...
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Journal Article

Ontogeny of Elliptocephala, Paradoxides, Sao, Blainia and Triarthrus (Trilobita) Free

Harry Blackmore Whittington
Published: 01 September 1957
Journal of Paleontology (1957) 31 (5): 934–946.
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Journal Article

New rhenopyrgid edrioasteroids (Echinodermata) and their implications for taxonomy, functional morphology, and paleoecology Available to Purchase

Timothy A. M. Ewin, Markus Martin, Phillip Isotalo, Samuel Zamora
Published: 01 January 2020
Journal of Paleontology (2020) 94 (1): 115–130.
DOI: https://doi.org/10.1017/jpa.2019.65
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Fossils from trilobite beds. A) Ventral view of pyritized Triarthrus eatoni (YPM.516160 and 516161). B) Lateral view of pyritized Triarthrus eatoni (YPM.227952). C) Fully articulated unpyritized Triarthrus eatoni, (Bed 822, YPM.221894). D) Pyritized ostracode (Bed 906, YPM.307293). E) Ventral view of pyritized Cryptolithus bellulus (YPM.509987). A, B, and E are from the Martin Quarry, Whetstone Gulf Formation. C and D are from the Walcott Quarry, Frankfort Shale.

Fossils from trilobite beds. A) Ventral view of pyritized Triarthrus eatoni... Available to Purchase

Published: 01 November 2011
FIGURE 4— Fossils from trilobite beds. A) Ventral view of pyritized Triarthrus eatoni (YPM.516160 and 516161). B) Lateral view of pyritized Triarthrus eatoni (YPM.227952). C) Fully articulated unpyritized Triarthrus eatoni, (Bed 822, YPM.221894). D) Pyritized ostracode (Bed 906, YPM.307293). E
Journal Article

TRIARTHRINID TRILOBITES (OLENIDAE) FROM THE MIDDLE AND UPPER ORDOVICIAN, PRECORDILLERA OF ARGENTINA Available to Purchase

GREGORY D. EDGECOMBE, BRIAN D. E. CHATTERTON, NORBERTO E. VACCARI, BEATRIZ G. WAISFELD
Published: 01 January 2005
Journal of Paleontology (2005) 79 (1): 89–109.
DOI: https://doi.org/10.1666/0022-3360(2005)079<0089:TTOFTM>2.0.CO;2
..., and the early Caradoc Triarthrus jachalensis ( Harrington and Leanza, 1957 ). Each of these species is described based on silicified material, including ontogenies, from the Las Aguaditas Formation. Porterfieldia maanssonae new species from the lower member of the Gualcamayo Formation (late Arenig) at Río...
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FIGURE 7—Trends in average abundance of Triarthrus eatoni (T), Leptobolus insignis (L), and Rafinesquina sp. (R), in the Alexandria submember along the study transect. Vertical scale for all plots is relative abundance by visual estimate, where 0 = absent, 1 = rare, 2 = common, and 3 = abundant. A) Average abundances for the entire Alexandria submember. B) Average abundances for each cycle. T: Triarthrus eatoni; L: Leptobolus insignis; R: Rafinesquina sp. See Figure 3 for explanation of abbreviations. Data for Triarthrus and Leptobolus at Maysville from C.E. Brett (personal communication, 2003). Data for Rafinesquina at Maysville from A.J. Webber (personal communication, 2003)

FIGURE 7 —Trends in average abundance of Triarthrus eatoni (T), Leptobol... Available to Purchase

Published: 01 March 2008
FIGURE 7 —Trends in average abundance of Triarthrus eatoni (T), Leptobolus insignis (L), and Rafinesquina sp. (R), in the Alexandria submember along the study transect. Vertical scale for all plots is relative abundance by visual estimate, where 0 = absent, 1 = rare, 2 = common, and 3
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Grooming setae of Triarthrus eatoni and reconstructions of grooming behaviour: (a–e) T. eatoni, GLAHM 163103, close-up of shaft setae in (b–e) being marked in (a); (f) T. eatoni, setae on the margin of gill shaft and the distal portion of the gill filaments, YPM 220; (g) setae on the gill shaft of T. eatoni, USNM 65527; (h) setae on the gill shaft of T. eatoni, USNM 400932. White arrows point to shaft setae. ds, distal seta of the gill filament. Scale bars: 0.2 mm (c, f–h); 1 mm (b, d, e); 5 mm (a).

Grooming setae of Triarthrus eatoni and reconstructions of grooming behav... Available to Purchase

Published: 15 February 2023
Fig. 3. Grooming setae of Triarthrus eatoni and reconstructions of grooming behaviour: (a–e) T. eatoni , GLAHM 163103, close-up of shaft setae in (b–e) being marked in (a); (f) T. eatoni , setae on the margin of gill shaft and the distal portion of the gill filaments, YPM 220; (g) setae
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A ventral view of the olenid trilobite Triarthrus eatoni from the Ordovician of New York State (U.S.A.) showing exceptional preservation of appendages. Scale bar, 5 mm. (Natural History Museum, London; photo by J.D.H.)

A ventral view of the olenid trilobite Triarthrus eatoni from the Ordovic... Open Access

Published: 01 February 2023
Figure 1. A ventral view of the olenid trilobite Triarthrus eatoni from the Ordovician of New York State (U.S.A.) showing exceptional preservation of appendages. Scale bar, 5 mm. (Natural History Museum, London; photo by J.D.H.)
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Aspects of the growth of the olenid trilobite Triarthrus eatoni; A, Length–frequency (L/F) sample assembled by Cisne (1973), with his assumed annual groups (I to V); B, electronic length frequency analysis (ELEFAN) analysis of the same L/F data, after regrouping them in 3 mm bins and restructuring via a smoothing procedure to identify peaks (black, positive histograms) and troughs (white, negative histograms), which allowed a von Bertalanffy growth function (VBGF) parameter set to be determined that produced a growth curve that hit most peaks and avoided most troughs; C, goodness of fit of a VBGF with L∞ = 41 mm with over a wide range of K values, identifying K = 0.29 yr−1 as the best estimate; D, the length and likely weight growth curves for T. eatoni.

Aspects of the growth of the olenid trilobite Triarthrus eatoni ; A, Lengt... Open Access

Published: 01 February 2023
Figure 3. Aspects of the growth of the olenid trilobite Triarthrus eatoni ; A, Length–frequency (L/F) sample assembled by Cisne ( 1973 ), with his assumed annual groups (I to V); B, electronic length frequency analysis (ELEFAN) analysis of the same L/F data, after regrouping them in 3 mm bins
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Estimation of mortality rates (M, yr−1) in Triarthrus eatoni through catch curves. A, The catch curve proposed by Cisne (1973), assuming that the four size groups in Fig. 3A are successive annual reproductive “pulses”; B, a length-converted catch curve based on the length–frequency (L/F) data in Fig. 3A but using the VBGF in Fig. 3B,D to convert length to relative ages. The three open circles were omitted from the computation because they belong to the “medium” size, many of which had been given away to other collections (see text).

Estimation of mortality rates ( M , yr −1 ) in Triarthrus eatoni through ... Open Access

Published: 01 February 2023
Figure 4. Estimation of mortality rates ( M , yr −1 ) in Triarthrus eatoni through catch curves. A, The catch curve proposed by Cisne ( 1973 ), assuming that the four size groups in Fig. 3A are successive annual reproductive “pulses”; B, a length-converted catch curve based on the length
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Pyritized specimens of Triarthrus eatoni from the Ordovician Whetstone Gulf Formation (Lorraine Group), upstate New York (USA). A: Ventrally preserved specimen (Yale Peabody Museum [YPM] 535703) showing nine eggs in the specimen’s left genal angle. B: Ventrally preserved specimen (YPM 535704) showing four eggs in the specimen’s right genal angle. C: Close-up of the egg-bearing region from the specimen in B. D: Close up of the egg-bearing region from the specimen in A. E: Scanning electron microscopy (SEM) image of the eggs from the specimen in A and D. Note that the perspective is twisted ∼180° from that in D. F: SEM image of an egg from E. G: Close-up SEM image of the egg surface from F. Note the dominant framboids and rare euhedral crystals of pyrite. H: Close-up of a limb from A. Note the dominant framboids and rare euhedral crystals of pyrite. I: SEM image of a disarticulated cranidium (YPM 238366) that was replaced with pyrite. J: SEM image showing the replacement fabric from I. Note the dominant euhedral crystals of pyrite. K–M: Dorsal digital reconstruction of the specimen in A derived from microcomputed tomography scan data. L: Ventral reconstruction. M: Left-ventral reconstruction. Scale bars in A and B are 5 mm long; scale bars in C and D are 2 mm long.

Pyritized specimens of Triarthrus eatoni from the Ordovician Whetstone Gu... Available to Purchase

Published: 01 March 2017
Figure 2. Pyritized specimens of Triarthrus eatoni from the Ordovician Whetstone Gulf Formation (Lorraine Group), upstate New York (USA). A: Ventrally preserved specimen (Yale Peabody Museum [YPM] 535703) showing nine eggs in the specimen’s left genal angle. B: Ventrally preserved specimen (YPM
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Figure9—Triarthrus jachalensis (Harrington and Leanza, 1957). 1–3, 5, 6, Los Azules Formation, Quebrada Los Azules and Quebrada Amarilla. 1, Dorsal view of cranidium, yoked librigenae, and partial thorax CORD-PZ 14274, ×5.1; 2, dorsal view of cranidium CEGH-UNC 21216, ×5.4; 3, dorsal view of cranidium CEGH-UNC 21215, ×6.2; 5, dorsal view of thoracopygidium and yoked librigenae CORD-PZ 14253, ×5.8; 6, dorsal view of three partial thoracopygidia CORD-PZ 14253, ×6.6. 4, Las Aguaditas Formation, section Las Aguaditas South. Dorsal view of silicified axial shield CEGH-UNC 21471, ×9.6

Figure 9 — Triarthrus jachalensis ( Harrington and Leanza, 1957 ). 1 – 3... Available to Purchase

Published: 01 January 2005
Figure 9 — Triarthrus jachalensis ( Harrington and Leanza, 1957 ). 1 – 3, 5, 6, Los Azules Formation, Quebrada Los Azules and Quebrada Amarilla. 1, Dorsal view of cranidium, yoked librigenae, and partial thorax CORD-PZ 14274, ×5.1; 2, dorsal view of cranidium CEGH-UNC 21216, ×5.4; 3
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Figure10—Triarthrus jachalensis. Las Aguaditas Formation; 1–5, 8–10, Las Aguaditas south, 113.65 m above base of large breccia unit except 3, LAS-B; 6, 7, 11–13, 15, 17, 18, Las Aguaditas north; 14, 16, 19, Mogotes Azules. 1, Dorsal view of degree 2 meraspis CEGH-UNC 21472, ×35.7; 2, dorsal view of degree 2 meraspis CEGH-UNC 21473, ×35.8; 3, dorsal view of degree 3 meraspis CEGH-UNC 21474, ×27; 4, dorsal view of degree 2 meraspis CEGH-UNC 21475, ×35.4; 5, dorsal view of cranidium CEGH-UNC 21476, ×17.8; 6, enrolled degree 2 meraspis CEGH-UNC 21477, LA-3, ×36.9; 7, dorsal view of transitory pygidium, probably degree 2, CEGH-UNC 21478, LA-D, ×58.3; 8, dorsal view of thorax CEGH-UNC 21479, ×20.8; 9, ventral view of meraspid cephalon and partial thorax CEGH-UNC 21480, ×35.8; 10, dorsal view of cranidium CEGH-UNC 21481, ×23.7; 11, dorsal view of cephalon CEGH-UNC 21482, LA-3, ×10; 12, dorsal view of cranidium CEGH-UNC 21483, LA-3, ×10; 13, dorsal view of pygidium CEGH-UNC 21484, LA-E, ×26.7; 14, dorsal view of thoracopygidium CEGH-UNC 21485, ×19.8; 15, dorsal view of librigena, CEGH-UNC 21486, 5 m above LA-2, ×42.6; 16, ventral view of thorax, dorsal view of pygidium CEGH-UNC 21487, 20; 17, dorsal view of cranidium CEGH-UNC 21488, LA-3, ×9.2; 18, dorsal view of pygidium with parts of three thoracic segments CEGH-UNC 21489, LA-3, ×10; 19, dorsal view of thoracopygidium CEGH-UNC 21490, ×19.6

Figure 10 — Triarthrus jachalensis . Las Aguaditas Formation; 1 – 5, 8 – ... Available to Purchase

Published: 01 January 2005
Figure 10 — Triarthrus jachalensis . Las Aguaditas Formation; 1 – 5, 8 – 10, Las Aguaditas south, 113.65 m above base of large breccia unit except 3, LAS-B; 6, 7, 11 – 13, 15, 17, 18, Las Aguaditas north; 14, 16, 19, Mogotes Azules. 1, Dorsal view of degree 2 meraspis CEGH-UNC 21472
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Figure11—Triarthrus jachalensis. Las Aguaditas Formation, Quebrada de Las Aguaditas, 5 m above LA-2. 1, Dorsal view of cranidium CEGH-UNC 21491, ×65.3; 2, ventral view of cranidium, yoked librigenae, and thoracic segment CEGH-UNC 21492, ×24.7; 3, dorsal view of yoked librigenae CEGH-UNC 21493, ×42.3; 4, dorsal view of cranidium CEGH-UNC 21494, ×36.6; 5, dorsal view of yoked librigenae CEGH-UNC 21495, ×24.6; 6, dorsal view of yoked librigenae CEGH-UNC 21496, ×50; 7, dorsal view of cranidium CEGH-UNC 21497, ×28.8; 8, posterodorsal view of thoracic segment CEGH-UNC 21498, ×35.6; 9, dorsal view of cranidium CEGH-UNC 21499, ×32.9; 10, dorsal view of librigena CEGH-UNC 21500, ×37; 11, dorsal view of transitory pygidium CEGH-UNC 21501, ×57; 12, dorsal view of (?larger instar degree 2) transitory pygidium CEGH-UNC 21502, ×62; 13, dorsal view of pygidium CEGH-UNC 21503, ×21.9; 14, dorsal view of transitory pygidium CEGH-UNC 21504, ×63.3

Figure 11 — Triarthrus jachalensis . Las Aguaditas Formation, Quebrada de ... Available to Purchase

Published: 01 January 2005
Figure 11 — Triarthrus jachalensis . Las Aguaditas Formation, Quebrada de Las Aguaditas, 5 m above LA-2. 1, Dorsal view of cranidium CEGH-UNC 21491, ×65.3; 2, ventral view of cranidium, yoked librigenae, and thoracic segment CEGH-UNC 21492, ×24.7; 3, dorsal view of yoked librigenae CEGH-UNC
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Figure 4. Small (A) to large (L) specimens of Triarthrus becki. A, Meraspis, NYSM 16781, Cephalic length (CL) = 0.97 mm. B, Meraspis, NYSM 16782, CL = 1.13 mm. C, Meraspis, NYSM 16783, CL = 1.31 mm. D, Meraspis, NYSM 16784, CL = 1.41 mm. E, Meraspis, NYSM 16785, CL = 1.49 mm. F, Meraspis, NYSM 17058, CL = 1.72 mm. G, Meraspis, NYSM 17059, CL = 1.91 mm. H, Meraspis, NYSM 17060, CL = 2.13 mm. I, Holaspis, NYSM 17061, CL = 3.10 mm. J, Holaspis, NYSM 17062, CL = 4.25 mm. K, Holaspis, NYSM 17063, CL = 5.39 mm. L, Holaspis, NYSM 17064, CL = 6.42 mm. These 12 specimens are reposited in the New York State Museum as hypotypes

Figure 4. Small (A) to large (L) specimens of Triarthrus becki . A, Meras... Available to Purchase

Published: 01 January 2002
Figure 4. Small (A) to large (L) specimens of Triarthrus becki . A, Meraspis, NYSM 16781, Cephalic length (CL) = 0.97 mm. B, Meraspis, NYSM 16782, CL = 1.13 mm. C, Meraspis, NYSM 16783, CL = 1.31 mm. D, Meraspis, NYSM 16784, CL = 1.41 mm. E, Meraspis, NYSM 16785, CL = 1.49 mm. F, Meraspis, NYSM
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Figure 5. Twelve landmark points on the cranidium exoskeleton of Triarthrus becki

Figure 5. Twelve landmark points on the cranidium exoskeleton of Triarthr... Available to Purchase

Published: 01 January 2002
Figure 5. Twelve landmark points on the cranidium exoskeleton of Triarthrus becki
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New soft-bodied and delicate fossils from the new Beecher's-type beds. A: Ventral view of Triarthrus eatoni (Yale Peabody Museum, YPM 509231); note ostracod (arrowed, YPM 223943), like that in C, splayed across its midline. B: Lateral view of Triarthrus eatoni (YPM 223935). C: Ostracod (YPM 223936). Other notable fossils include the following. D: &gt;30 legged ?crustacean (YPM 223937). E: Cryptolithus bellulus (YPM 509987). F: Ophiuroid (YPM 509229), and G: ?alga (YPM 223942). Scale bars = 1 cm, with exception of C, where scale bar = 1 mm. A, E, and G are from Martin Quarry, B and F are from Beecher's Trilobite Bed site, and C and D are from Jo's Quarry.

New soft-bodied and delicate fossils from the new Beecher's-type beds. A: V... Available to Purchase

Published: 01 October 2009
Figure 2. New soft-bodied and delicate fossils from the new Beecher's-type beds. A: Ventral view of Triarthrus eatoni (Yale Peabody Museum, YPM 509231); note ostracod (arrowed, YPM 223943), like that in C, splayed across its midline. B: Lateral view of Triarthrus eatoni (YPM 223935). C
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Reconstructions of trilobite grooming behaviour: (a) partial grooming reconstruction of Olenoides serratus; (b) partial grooming reconstruction of Triarthrus eatoni. The fouling materials are reconstructed as randomly distributed irregular yellow shapes.

Reconstructions of trilobite grooming behaviour: (a) partial grooming recon... Available to Purchase

Published: 15 February 2023
Fig. 4. Reconstructions of trilobite grooming behaviour: (a) partial grooming reconstruction of Olenoides serratus ; (b) partial grooming reconstruction of Triarthrus eatoni . The fouling materials are reconstructed as randomly distributed irregular yellow shapes.