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Magnigondolella, a new conodont genus from the Triassic of North America

Published online by Cambridge University Press:  23 November 2017

Martyn L. Golding
Affiliation:
Geological Survey of Canada, 1500-605 Robson Street, Vancouver, British Columbia, Canada, V6B 5J3 〈martyn.golding@canada.ca〉, 〈mike.orchard@canada.ca〉
Michael J. Orchard
Affiliation:
Geological Survey of Canada, 1500-605 Robson Street, Vancouver, British Columbia, Canada, V6B 5J3 〈martyn.golding@canada.ca〉, 〈mike.orchard@canada.ca〉

Abstract

The new conodont genus Magnigondolella is recognized based on specimens recovered from the Anisian (Middle Triassic) of British Columbia in Canada, and Nevada in the USA. This new genus encompasses problematic specimens with high carinas, which have recently been collectively referred to as Neogondolella ex gr. regalis Mosher. Ten species from North America are herein assigned to Magnigondolella n. gen., including the eight new species M. alexanderi, M. cyri, M. julii, M. nebuchadnezzari, M. salomae, M. n. sp. A, M. n. sp. B, and M. n. sp. C, as well as the two existing species M. regalis (Mosher) and M. dilacerata (Golding and Orchard). Other species from the Tethys region are also tentatively assigned to Magnigondolella n. gen. Based on published records, the genus appears to range from the Spathian to the upper Anisian in North America. The recognition of eight new species from the Anisian significantly increases the conodont biodiversity of this period, which has previously been regarded as a time of low diversity. Although some of the species included within Magnigondolella n. sp. have relatively long stratigraphic ranges, many have been identified in both British Columbia and Nevada, and therefore show potential for biostratigraphic correlation on a regional scale.

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Copyright © 2017, The Paleontological Society 
Figure 0

Figure 1Chart showing the occurrences of the conodont species reported in this paper within lower and middle Anisian ammonoid zones. Squares indicate occurrences within the ammonoid zones of Nevada, and circles indicate occurrences within the ammonoid zones of B.C. Dashed lines between symbols indicate the inferred stratigraphic range of these species. Note that the ranges of M. alexanderi n. sp., M. nebuchadnezzari n. sp., M. julii n. sp., and M. salomae n. sp. continue into the upper Anisian. B.C. ammonoid zones after Tozer (1994) and Bucher (2002); Nevada ammonoid zones and correlation after Monnet and Bucher (2005a).

Figure 1

Figure 2Maps showing the geographic locations of samples collected from Nevada and B.C.

Figure 2

Table 1Table of samples from the Anisian of British Columbia and Nevada that contain species of Magnigondolella. Other species recorded from these samples have previously been described in Golding and Orchard (2016). Samples from Nevada were collected by H. Bucher (field nos. HB), and those from B.C. were collected by M. Golding and J.-P Zonneveld (curation nos. V-) or by M.J. Orchard and E.T. Tozer (curation nos. C-, O-). Ages are given to the level of ammonoid zone or subzone (see Fig. 1) where possible, or inferred on the basis of the complete conodont fauna. Conodonts: M.=Magnigondolella, N.=Neogondolella. Ammonoids: Ac.=Acrochordiceras, Az.=Azarianites, G.=Grambergia, I.=Intornites, J.=Japonites, L.=Lenotropites, Pa.=Paracrochordiceras, Ps.=Pseudokeyserlingites, T.=Tetsaoceras, U.=Unionvillites.

Figure 3

Figure 3Apparatus of Magnigondolella n. gen. (P1) GSC Type No. 131574; (P2) GSC Type No. 131575; (M) GSC Type No. 131576; (S1) GSC Type No. 131577; (S2) GSC Type No. 131578; (S3) GSC Type No. 131579; (S4) GSC Type No. 131580; (S0) GSC Type No. 131581; all from the Prida Formation (Lenotropites caurus Zone, lower Anisian), GSC Cur. No. C-159809, Bloody Canyon, northern Humboldt Range, Nevada.

Figure 4

Figure 4Magnigondolella alexanderi n. gen. n. sp. (1, 2) GSC Type No. 131582, from the Toad Formation (Lenotropites caurus Zone, lower Anisian), GSC Cur. No. C-201922, Mile Post 375 East, B.C.; (3–5) GSC Type No. 131583, from the Toad Formation (Tetsaoceras hayesi Zone, middle Anisian), GSC Cur. No. C-90852, Liard River, B.C.; (6–8) GSC Type No. 131584, from the Toad Formation (T. hayesi Zone, middle Anisian), GSC Cur. No. O-99588, East Toad River, B.C.; (9–11) GSC Type No. 131585, from the Favret Formation (Intornites mctaggarti Subzone, Acrochordiceras hyatti Zone, middle Anisian), GSC Cur. No. C-176314, Favret Canyon, Augusta Mountains, Nevada; (12–14) GSC Type No. 131586 (holotype), from the Toad Formation (Paracrochordiceras americanum Zone, lower Anisian), GSC Cur. No. C-302187, Mile Post 375 East, B.C.

Figure 5

Figure 5Magnigondolella cyri n. gen. n. sp. (1–3) GSC Type No. 131587, from the Prida Formation (Lenotropites caurus Zone, lower Anisian), GSC Cur. No. C-159809, northern Humboldt Range, Nevada; (4–6) GSC Type No. 131492, from the Doig Formation (middle Anisian), GSC Cur. No. V-002999, Petro-Canada Kobes c-074-G/094-b-09 well, B.C.; (7–9) GSC Type No. 131588 (holotype), from the Favret Formation (Intornites mctaggarti Subzone, Acrochordiceras hyatti Zone, middle Anisian), GSC Cur. No. C-176314, Favret Canyon, Augusta Mountains, Nevada; (10–12) GSC Type No. 131589, from the Doig Formation (lower Anisian), GSC Cur.No. V-002992, Petro-Canada Kobes d-048-A/094-b-09 well, B.C.

Figure 6

Figure 6Magnigondolella julii n. gen. n. sp. (1–3) GSC Type No. 131590, from the Favret Formation (Unionvillites hadleyi Subzone, Acrochordiceras hyatti Zone, middle Anisian), GSC Cur. No. C-176526, Muller Canyon, Augusta Mountains, Nevada; (4–6) GSC Type No. 131591, from the Prida Formation (Lenotropites caurus Zone, lower Anisian), GSC Cur. No. C-159809, northern Humboldt Range, Nevada; (7–9) GSC Type No. 131592; (10–12) GSC Type No. 131593 (holotype), from the Toad Formation (Tetsaoceras hayesi Zone, middle Anisian), GSC Cur. No. O-68294, Mile Post 375 West, B.C.; (13–15) GSC Type No. 131493, from the Doig Formation (middle Anisian), GSC Cur. No. V-002955, Murphy Swan d-054-B/094-P-09 well, B.C.

Figure 7

Figure 7Magnigondolella nebuchadnezzari n. gen. n. sp. (1–3) GSC Type No. 131594, from the Doig Formation (lower Anisian), GSC Cur. No. V-002992, Petro-Canada Kobes d-048-A/094-b-09 well, B.C.; (4–6) GSC Type No. 131595, from the Prida Formation (Intornites mctaggarti Subzone, Acrochordiceras hyatti Zone, middle Anisian), GSC Cur. No. C-176324, Congress Canyon, northern Humboldt Range, Nevada; (7–9) GSC Type No. 131596, from the Toad Formation (Tetsaoceras hayesi Zone, middle Anisian), GSC Cur. No. O-68294, Mile Post 375 West, B.C.; (10–12) GSC Type No. 131506 (holotype), from the Toad Formation (Tetsaoceras hayesi Zone, middle Anisian), GSC Cur. No. C-101077, Mile Post 375 East, B.C.

Figure 8

Figure 8Magnigondolella regalis (Mosher). (1–3) GSC Type No. 25048 (holotype), from the Toad Formation (Tetsaoceras hayesi Zone, middle Anisian), GSC Cur. No. O-68294, Mile Post 375 West, B.C.

Figure 9

Figure 9Magnigondolella salomae n. gen. n. sp. (1–3) GSC Type No. 131597, from the Toad Formation (Tetsaoceras hayesi Zone, middle Anisian), GSC Cur. No. O-68294, Mile Post 375 West, B.C.; (4–6) GSC Type No. 131476, from the Doig Formation (middle Anisian), GSC Cur.No. V-002978, Talisman Altares 16-17-083-25W6 well, B.C.; (7–9) GSC Type No. 131598, (holotype) from the Toad Formation (Paracrochordiceras americanum Zone, lower Anisian), GSC Cur. No. C-302187, Mile Post 375 East, B.C.

Figure 10

Figure 10Magnigondolella n. gen. n. sp. A. (1–3) GSC Type No. 131599; (4–6) GSC Type No. 131600; both from the Favret Formation (Intornites mctaggarti Subzone, Acrochordiceras hyatti Zone, middle Anisian), GSC Cur. No. C-176314, Favret Canyon, Augusta Mountains, Nevada.

Figure 11

Figure 11Magnigondolella n. gen. n. sp. B. (1–3) GSC Type No. 131601; (4–6) GSC Type No. 131602; both from the Favret Formation (Intornites mctaggarti Subzone, Acrochordiceras hyatti Zone, middle Anisian), GSC Cur. No. C-176314, Favret Canyon, Augusta Mountains, Nevada.

Figure 12

Figure 12Magnigondolella n. gen. n. sp. C. (1–3) GSC Type No. 131603; (4–6) GSC Type No. 131604; (7–9) GSC Type No. 131605; (10–12) GSC Type No. 131606; all from the Prida Formation (Intornites mctaggarti Subzone, Acrochordiceras hyatti Zone, middle Anisian), GSC Cur. No. C-176324, Congress Canyon, northern Humboldt Range, Nevada.

Figure 13

Table 2Table showing the number of P1 elements of Magnigondolella n. gen. species identified from localities in B.C. and Nevada.