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Introduction
The ammonoid fossil record for the Anisian (Middle Triassic) of British Columbia (B.C.) is well established and forms the basis for the recognition of eight ammonoid zones and two subzones (Tozer, Reference Tozer1994; Bucher, Reference Bucher2002). In comparison, the conodont biostratigraphical record is less well resolved, in part because of the perceived low diversity of the microfauna. This work provides a conodont taxonomy that will underpin an improved biozonation and an intercalibration with the ammonoid standard that will enable dating in the absence of ammonoid faunas, as is generally the case in the subsurface of B.C. These improved biostratigraphical tools will in turn allow greater precision in determining the timing of events that were occurring in North America during the Anisian. This was a time of significant tectonic activity on the western margin of North America, with collision between the continent and pericratonic terranes that began in the latest Permian (Beranek and Mortensen, Reference Beranek and Mortensen2011). Furthermore, some of the rocks deposited in B.C. during the Anisian now contain important resources of hydrocarbons. Understanding the mechanisms of continent-scale tectonics and the formation of widespread source and reservoir rocks requires a refined and widely applicable biochronological scale.
Previously, few conodont species have been identified from the Anisian of North America, with most specimens being assigned to broadly defined concepts of Neogondolella mombergensis (Tatge), N. regalis Mosher, N. bulgarica (Budurov and Stefanov), N. constricta (Mosher and Clark), N. transita Kozur and Mostler, and N. shoshonensis Nicora (Mosher and Clark, Reference Mosher and Clark1965; Mosher, Reference Mosher1973; Nicora, Reference Nicora1976, Reference Nicora1977; Nicora and Kovács, Reference Nicora and Kovács1984; Ritter, Reference Ritter1989; Orchard, Reference Orchard1994). Nicora et al. (Reference Nicora, Kozur and Mietto1980) and Orchard (Reference Orchard2010) identified some less common taxa from the Anisian of North America, but additional species of Neogondolella identified by Orchard and Tozer (Reference Orchard and Tozer1997) have not hitherto been described.
To facilitate the revision of Neogondolella, new collections were made from measured sections of Anisian outcrop on the Alaska Highway, as well as from cores taken from hydrocarbon wells drilled in the subsurface of northeastern B.C. These supplemented existing collections previously made by the second author in conjunction with E.T. Tozer, whose ammonoid zonal assignments are critical for intercalibration of the conodont and ammonoid schemes. These collections come from localities on the Alaska Highway, Liard River, and Toad River, including the type sections for some of the North American ammonoid zones of the Anisian.
Geologic setting
The Anisian rocks that crop out in northeastern B.C. belong to the Toad Formation. This formation consists primarily of siltstone, shale, fine-grained sandstone, and carbonate (Zonneveld, Reference Zonneveld2010). It formed in deep water and shows evidence for some deposition caused by turbidity currents (Ferri et al., Reference Ferri, Golding, Mortensen, Zonneveld and Orchard2010). The Toad Formation is not recognized in the subsurface, where Anisian rocks belong to the upper part of the Montney Formation and the lower part of the Doig Formation (Golding et al., Reference Golding, Orchard and Zonneveld2014), which are lateral equivalents of the Toad Formation. The Montney Formation consists of shale, siltstone, and very fine sandstone (Zonneveld, Reference Zonneveld2010), and the top of the formation is marked by an emergent surface, bioturbated by trace fossils belonging to the Glossifungites ichnofacies. The base of the Doig Formation is a condensed section formed during transgression over this emergent surface. The condensed section is rich in phosphate and is termed the Doig Phosphate Zone (Edwards et al., Reference Edwards, Barclay, Gibson, Kvill and Halton1994). Equivalent phosphate-rich horizons can be recognized in the Toad Formation in surface outcrop. Above this zone, the Doig Formation is primarily siltstone and sandstone. The Montney and Doig formations represent deposition in a wide range of environments, from offshore turbidites (e.g., Moslow, Reference Moslow2000) to the shoreface (e.g., Evoy and Moslow, Reference Evoy and Moslow1995).
The sediments of the Toad, Montney, and Doig formations were deposited on the margin of the ancestral North American continent. They were formed in the Peace River sub-basin of the Western Canada Sedimentary Basin (WCSB). The Peace River Basin was a transpressional basin that stretched from the B.C.-Yukon border down into the United States (Davies, Reference Davies1997). During the Triassic, rock units currently present in northeastern B.C. were situated at mid-latitude north of the equator and the climate was arid. A significant amount of sediment deposited in the basin is thought to have been windblown (Davies, Reference Davies1997), and palaeocurrent indicators suggest that the bulk of the sediment was derived from the continent (Pelletier, Reference Pelletier1965; Arnold, Reference Arnold1994).
In North America, the Anisian is divided into the lower, middle, and upper Anisian sub-stages. Tozer recognized seven ammonoid zones in the Anisian of B.C. (Tozer, Reference Tozer1967, Reference Tozer1994; Silberling and Tozer, Reference Silberling and Tozer1968), and Bucher (Reference Bucher2002) added an additional zone first recognized in Nevada (Fig. 1), where far more complete Anisian sections are known (Monnet and Bucher, Reference Monnet and Bucher2005; Fig. 1). The lower Anisian of B.C. consists of the Silberlingites mulleri Zone, the Lenotropites caurus Zone, and the Paracrochordiceras americanum Zone; the L. caurus Zone is further divided into two subzones, the Azarianites bufonis Subzone and the Grambergia nahwisi Subzone. The middle Anisian consists of the Buddhaites hagei, Tetsaoceras hayesi, and Hollandites minor zones. The upper Anisian contains the Eogymnotoceras deleeni and Frechites chischa zones. The collections described in this paper come from the L. caurus, P. americanum, T. hayesi, H. minor, and E. deleeni zones.
Chart showing the ammonoid biozonation of the Anisian in B.C. and Nevada. Ammonoid zones in B.C. are based on the work of Tozer (Reference Tozer1994) and Bucher (Reference Bucher2002); those of Nevada and their correlation with the sequence in B.C. are based on the work of Monnet and Bucher (Reference Monnet and Bucher2005).
Materials and methods
New material for this study was collected from the North Tetsa Phosphate (UTM 416937 6503960) and Yellow Bluffs (UTM 426656 6502261) sections on the Alaska Highway in northeastern B.C. (Tuchodi Lakes map area 094 K; Fig. 2), as well as from six cores taken from the subsurface of B.C. in the vicinity of Fort St. John (Petro-Canada Kobes d-048-A/094-B-09; Petro-Canada Kobes c-074-G/094-B-09; Talisman Altares c-085-I/094-B-01; ARC Dawson 07-13-79-15W6; Murphy Swan d-054-B/093-P-09; and Shell Groundbirch 16-02-078-22W6; Fig. 3). Archival collections come from the Mile Post 375 West (UTM 427661 6502275), Mile Post 375 East (UTM 428009 6501991), and North Tetsa Hill (UTM 420150 6507317) sections on the Alaska Highway (Tuchodi Lakes map area 094 K; Fig. 2); the North Liard (UTM 378605 6576703) and South Liard (UTM 393957 6584220) sections on Liard River (Toad River map area 094 N; Fig. 4); and the East Toad River (UTM 403002 6562443) section on the Toad River (Toad River map area 094 N; Fig. 4).
Map showing the location of sections on the Alaska Highway in northeastern B.C. NTH = North Tetsa Hill, NTP = North Tetsa Phosphate, YB = Yellow Bluffs, MP375W = Mile Post 375 West, MP375E = Mile Post 375 East.
Map showing the location of sections on the Liard and Toad Rivers in northeastern B.C. SL=South Liard, NL=North Liard, TR=East Toad River.
Map showing the location of subsurface sections and their relation to the Montney hydrocarbon play trend in B.C. 1 = Petro-Canada Kobes c-074-G/094-B-09, 2 = Petro-Canada Kobes d-048-A/094-B-09, 3 = Talisman Altares c-085-I/094-B-01, 4 = Shell Groundbirch 16-02-078-22W6, 5 = Murphy Swan d-054-B/093-P-09, 6 = ARC Dawson 07-13-79-15W6. Montney play trend after Hayes (Reference Hayes2012).
Samples were collected from calcareous siltstone beds from the Toad Formation on the Alaska Highway, and from the age-equivalent Montney and Doig formations in the subsurface. Processing was carried out at the Geological Survey of Canada and the University of British Columbia following the methodology outlined in Stone (Reference Stone1987) and Jeppsson et al. (Reference Jeppsson, Anehus and Fredholm1999). A total of 50 new samples were collected, and of these, 11 contained conodonts that could be identified as new species (Table 1). Combined with 14 archival collections from the Geological Survey of Canada (Table 1), a total of 25 collections were used for this study.
New and archived samples that contain examples of the new species described in this paper. Ages are given to the level of ammonoid zone (see Fig. 1) where possible, or inferred based on the complete conodont fauna. N. = Neogondolella; P. = Paragondolella; KB = Kelly Bushing.
Repositories and institutional abbreviations
Illustrated specimens are housed at the National type Collection of Invertebrate and Plant Fossils at the Geological Survey of Canada (GSC) in Ottawa, Ontario, Canada.
Biostratigraphy
The stratigraphic ranges of the eight new species described herein are shown in Figure 5. In addition to these new species, a number of other new morphotypes of existing species have been recognized from collections in northeastern B.C. (Table 1), including specimens of Negondolella ex gr. regalis, N. ex gr. constricta, N. ex gr. shoshonensis, N. bifurcata (Budurov and Stefanov), and Paragondolella ex gr. lierbermani (Kovács and Krystyn). These groups are currently under revision, and a description of the new morphotypes will be presented in a future publication. Together, the new taxa have allowed a new, more refined conodont biostratigraphical scheme to be developed for the Anisian of British Columbia, which has been published in part by Golding (Reference Golding2014) and Golding et al. (Reference Golding, Orchard and Zonneveld2014).
Chart showing the occurrences within ammonoid zones of the new conodont species described in this paper. The squares indicate occurrences within the ammonoid zones of B.C., and circles indicate occurrences within the ammonoid zones of Nevada. Dashed lines between symbols indicate the inferred stratigraphic range of these species. Note that the ranges of Neogondolella panlaurentia, N. hastata, and N. cuneiforme extend into the Olenekian and Ladinian, respectively.
Some of the new species recognized in the present paper also allow correlation on a regional scale (Fig. 5). Neogondolella panlaurentia has been identified in the lower Anisian Lenotropites caurus Zone of B.C., as well as in published collections from the Spathian (upper Olenekian) of the Canadian Arctic (Keyserlingites subrobustus Zone; Orchard, Reference Orchard2008) and in unpublished collections from the lower Anisian of Nevada (Japonites welteri Zone), making this species a good indicator for the Spathian–Anisian boundary interval in North America.
Neogondolella hastata, which ranges in age from the middle Anisian Tetsaoceras hayesi Zone to the lower Ladinian Tuchodiceras poseidon Zone in B.C., has also been identified in collections from the Intornites mctaggarti Subzone of the Acrochordiceras hyatti Zone, the Augustaceras escheri Subzone of the Nevadisculites taylori Zone (both middle Anisian), and the Frechites occidentalis Zone (upper Anisian) in Nevada, and from middle Anisian collections from the Canadian Arctic and Svalbard.
Neogondolella curva ranges from the lower Anisian L. caurus Zone to the middle Anisian Hollandites minor Zone in B.C., and is found in the Pseudodanubites nicholsi and A. escheri subzones of the middle Anisian N. taylori Zone in Nevada.
Neogondolella vellicata occurs in the lower Anisian L. caurus Zone in B.C., as well as in the Pseudokeyserlingites guexi Zone (lower Anisian) and A. hyatti Zone (middle Anisian) in Nevada.
Neogondolella tenera ranges from the H. minor Zone (middle Anisian) to Eogymnotoceras deleeni Zone (upper Anisian) in B.C., and has been identified in collections from the Favreticeras wallacei Subzone of the middle Anisian Balatonites shoshonensis Zone in Nevada.
Neogondolella indicta occurs in the middle Anisian H. minor Zone in B.C., as well as in the I. mctaggarti and Unionvillites hadleyi subzones of the A. hyatti Zone, and the P. nicholsi Subzone of the N. taylori Zone (all middle Anisian) in Nevada.
Systematic paleontology
Class Conodonta Pander, Reference Pander1856
Order Ozarkodinida Dzik, Reference Dzik1976
Family Gondolellidae Lindström, Reference Lindström1970
Genus Neogondolella Bender and Stoppel, Reference Bender and Stoppel1965
Type species
Gondolella mombergensis Tatge, Reference Tatge1956
Remarks
The genus Neogondolella was initially introduced by Bender and Stoppel (Reference Bender and Stoppel1965) to encompass Permian and Triassic species that had previously been placed into the genus Gondolella Stauffer and Plummer. The original diagnosis emphasized the lack of ornamentation on the platform of Neogondolella in contrast to Gondolella. Subsequently, the concept of Neogondolella has been interpreted in a number of different ways, and the genus has been defined by various morphological characteristics of the segminiplanate P1 element, including its ontogenetic development (Sweet, Reference Sweet1970), and the nature of its basal pit (Kozur, Reference Kozur1989). A multi-element diagnosis for Neogondolella was given by Orchard and Rieber (Reference Orchard and Rieber1999), Orchard (Reference Orchard2005), and Goudemand et al. (Reference Goudemand, Orchard, Tafforeau, Urdy, Brühwiler, Brayard, Galfetti and Bucher2012), although the multi-element apparatus of the type species N. mombergensis has not yet been documented. The generic classification of Neogondolella should ultimately be based on the composition of the multi-element apparatus; however, the greatest morphological diversity is displayed by the P1 elements, which have been used to define species. The diversity of the P1 elements, together with the relatively small number of ramiform elements in the samples, makes it difficult to determine the multi-element apparatuses of any of the new species recognized in this study.
Neogondolella cuneiforme new species
Neogondolella cuneiforme n. sp. (1–3) GSC type no. 131541 (holotype), from the Toad Formation (Eogymnotoceras deleeni Zone, upper Anisian), GSC cur. no. 99566, East Toad River; (4–6) GSC type no. 131542, from the Liard Formation (Meginoceras meginae Zone, Ladinian), GSC cur. no. V-002626, Mile Post 386.
2014 Neogondolella n. sp. F; Reference GoldingGolding, p. 152, fig. 2.47, 1–6
Holotype
GSC type no. 131541 (Fig. 6.1–6.3), from the Eogymnotoceras deleeni Zone (upper Anisian) of the Toad Formation, GSC cur. no. 99566, East Toad River section, B.C.
Diagnosis
A species of Neogondolella in which the segminiplanate P1 element has a narrow, wedge-shaped platform with a squared-off posterior margin. The denticles of the carina are partially fused, low at the posterior and in the middle of the element, and progressively rise to the anterior where they form a high fixed blade. A narrow posterior platform brim is present, and the basal keel is wide.
Occurrence
In B.C.: GSC cur. no. 99566, East Toad River section; GSC cur. no. V-002619, Yellow Bluffs section; GSC cur. no. V-002626, Mile Post 386 section; Eogymnotoceras deleeni Zone (upper Anisian) to Meginoceras meginae Zone (lower Ladinian).
Description
The platform margins of the P1 element are subparallel to weakly divergent, with the widest part of the platform typically at the posterior. The platform margins taper evenly in the anterior third of the element, leaving no free blade. The posterior platform margin is quadrate and a posterior platform brim is present. Micro-reticulation is present on the platform margins. In side view, the element is evenly arched and the platform is thick with upturned margins. The cusp is small and subterminal. The carina is low, with fused denticles in the posterior and middle of the element that rise to the anterior, where a less fused blade is developed. The keel is low and wide, terminating in an open, subcircular basal loop that surrounds the terminal basal pit.
Etymology
From the Latin cuneus, meaning “wedge” and –forme, meaning “shaped,” in reference to the morphology of the platform in upper view.
Materials
Seven specimens from B.C.
Remarks
The marked differentiation of the blade and carina in this species separates it from most others described herein. Some morphotypes of Neogondolella ex gr. constricta have a similar platform shape to N. cuneiforme, but the carina of the former is much less fused and does not rise as steeply to the anterior. Some morphotypes of N. ex gr. regalis also have similar platforms to N. cuneiforme, but the carina of these morphotypes is much higher for the whole of its length. Morphotypes of Paragondolella ex gr. excelsa (Mosher) have a carina that is highest in the middle of the element. The carina of P. inclinata (Kovács) has a similar profile to that of N. cuneiforme but is higher in the posterior. The carina of P. sulcata Orchard is also highest at the anterior and lowest at the posterior; however, the carina is even lower in the posterior half of the element than that of N. cuneiforme and is commonly sunken. Neogondolella cuneiforme has also been identified in the lower Ladinian at Mile Post 386 on the Alaska Highway (Golding, Reference Golding2014), and an example from this section is illustrated in Figure 6.
Neogondolella curva new species
Neogondolella curva n. sp. (1–3) GSC type no. 131543; (4–6) GSC type no. 131544 (holotype); (7–9) GSC type no. 131545; all from the Toad Formation (Paracrochordiceras americanum Zone, lower Anisian), GSC cur. no. C-209952, Mile Post 375 East.
2014 Neogondolella n. sp. H; Reference GoldingGolding, p. 156, fig. 2.49, 1–12
Holotype
GSC type no. 131544 (Fig. 7.4–7.6), from the Paracrochordiceras americanum Zone (lower Anisian) of the Toad Formation, GSC cur. no. C-209952, Mile Post 375 East section, B.C.
Diagnosis
A species of Neogondolella in which the segminiplanate P1 element has a convex outer platform margin and an indented inner platform margin. The widest point of the platform is at the middle of the element. The posterior margin is narrowly to broadly rounded. The cusp is large and terminal to subterminal, and the carina is high and fused.
Occurrence
In B.C.: GSC cur. no. C-209952, Mile Post 375 East section; GSC cur. no. 99579, South Liard section; GSC cur. no. C-201917, North Tetsa Phosphate section; GSC cat. no. V-002513, Shell Groundbirch 16-02-078-22W6 well; GSC cat. no. V-002999, Petro-Canada Kobes c-074-G/094-B-09 well; Lenotropites caurus Zone (lower Anisian) to Hollandites minor Zone (middle Anisian). In Nevada: GSC cur. no. C-159823 (HB-246), GSC cur. no. C-176331 (HB-105), both Favret Canyon, Augusta Mountains; Pseudodanubites nicholsi Subzone (Nevadisculites taylori Zone, middle Anisian) to Augustaceras escheri Subzone (N. taylori Zone, middle Anisian).
Description
The widest part of the P1 element is at its midpoint. The platform margins taper from this point to the anterior of the element, and there is no free blade. The outer platform margin also tapers evenly to the posterior of the element; however, the inner margin is clearly indented in the posterior third of the element. Small and mid-sized specimens also show a further posterior constriction of the platform. In juveniles, the posterior margin is pointed, whereas in adults it is wider and more rounded. A narrow posterior platform brim also develops with growth. Micro-reticulation is present on the platform margins. In side view, the element is arched and the platform is relatively thin with upturned margins, becoming thicker and more upturned with growth. In juveniles, the inclined cusp is similar in size to other denticles, becoming larger with growth. A posterior denticle is sometimes present. The carina is high with an arched upper profile, and fused denticles that become increasingly so with growth. The keel is low and narrow in juveniles, becoming wider with growth. The keel terminates in an open, circular basal loop that surrounds the terminal basal pit.
Etymology
From the Latin curvus, meaning “bent,” in reference to the bent inner platform margin of the species.
Materials
20 specimens from B.C.; seven specimens from Nevada.
Remarks
Species belonging to the genus Budurovignathus have similar, asymmetrical platform margins to N. curva. However, the majority of those species have a free blade that is absent in N. curva. The species B. praehungaricus (Kovács) and B. hungaricus (Kozur and Végh) do not have a free blade, but show an anterior-shifted basal pit that contrasts with the terminal basal pit of N. curva.
Neogondolella dilacerata new species
Neogondolella dilacerata n. sp. (1–3) GSC type no. 131546, from the Toad Formation (Lenotropites caurus Zone, lower Anisian), GSC cur. no. 99574, North Liard River; (4–6) GSC type no. 131547; (7–9) GSC type no. 131509 (holotype); both from the Toad Formation (Paracrochordiceras americanum Zone, lower Anisian), GSC cur. no. C-209952, Mile Post 375 East.
2014 Neogondolella ex gr. regalis morphotype ζ; Reference GoldingGolding, p. 128, fig. 2.35, 1–9
2014 Neogondolella ex gr. regalis morphotype E nov.; Reference Golding, Orchard and ZonneveldGolding et al., fig. 3, 25–27
Holotype
GSC type no. 131509 (Fig. 8.7–8.9) from the Paracrochordiceras americanum Zone (lower Anisian) of the Toad Formation, GSC cur. no. C-209952, Mile Post 375 East section, B.C.
Diagnosis
A species of Neogondolella in which the segminiplanate P1 element has biconvex platform margins, the outer one of which is shorter than the inner, so as to cause posterior platform margin asymmetry. There is no posterior platform brim. The cusp and posterior denticle are the same size, are much larger than the other denticles, and are strongly inclined to the posterior. The carina is high and of uniform height.
Occurrence
In B.C.: GSC cur. no. 99574, North Liard River section; GSC cur. no. C-209952, Mile Post 375 East section; Grambergia nahwisi Subzone (Lenotropites caurus Zone, lower Anisian) to Paracrochordiceras americanum Zone (lower Anisian).
Description
The platform of the P1 element is narrow, biconvex, and is widest at the midpoint. The platform tapers evenly to the anterior and no free blade is present. The inner platform margin extends all the way to the posterior end of the element; however, the outer platform margin is truncated and terminates approximately level with the cusp. No posterior platform brim is present. Micro-reticulation is present on platform margins. In side view, the element is slightly arched and its platform margins are slightly upturned. The cusp is large and posteriorly inclined, and a posterior denticle of equal size and orientation is always present. The carina is uniformly high, and its denticles are inclined and strongly fused, particularly in the posterior two thirds. The keel is low and narrow, terminating in a rounded basal loop that surrounds the terminal basal cavity.
Etymology
Named after dilaceration, a developmental disturbance causing angulation in the root of a tooth, in reference to the distinctive truncation on one side of the posterior end of the platform.
Materials
11 specimens from B.C.
Remarks
The asymmetrical platform of Neogondolella dilacerata separates this species from others that share a similar carina, such as N. prava (Kozur, Reference Kozur1989) and N. n. sp. sensu Orchard et al. (Reference Orchard, Grǎdinaru and Nicora2007). Some morphotypes of N. ex gr. transita have asymmetrical platforms, but they also possess a posterior secondary keel which is absent in N. dilacerata.
Neogondolella hastata new species
Neogondolella hastata n. sp. (1, 2) GSC type no. 131548; (6–8) GSC type no. 131549; both from the Doig Formation (middle Anisian), GSC cur. no. V-002955, Murphy Swan d-054-B/094-P-09 well; (3–5) GSC type no. 131550; (9–11) GSC type no. 131507 (holotype); both from the Toad Formation (Tetsaoceras hayesi Zone, middle Anisian), GSC cur. no. 68204, Mile Post 375 East; (12, 13) GSC type no. 131551, from the Toad Formation (T. hayesi Zone, middle Anisian), GSC cur. no. 68294, Mile Post 375 West.
1973 Neogondolella mombergensis (Tatge); Reference MosherMosher, pl. 19, figs. 4, 6 only
1997 Neogondolella n. sp. N; Reference Orchard and TozerOrchard and Tozer, p. 682
2014 Neogondolella n. sp. A; Reference GoldingGolding, p. 142, fig. 2.42, 1–13
2014 Neogondolella n. sp. N sensu Orchard and Tozer; Reference Golding, Orchard and ZonneveldGolding et al., fig. 3, 16–18
Holotype
GSC type no. 131507 (Fig. 9.9–9.11), from the Tetsaoceras hayesi Zone (middle Anisian) of the Toad Formation, GSC cur. no. 68204, Mile Post 375 East section on the Alaska Highway, B.C.
Diagnosis
A species of Neogondolella in which the segminiplanate P1 element has a narrow, biconvex platform that tapers to a point at both the anterior and posterior ends. The cusp is large, inclined, and terminal. There is no posterior denticle and no posterior brim. The carina is low, of an even height for most of its length, and its denticles are discrete. In the largest specimens, a slightly higher, fixed blade develops at the anterior of the carina.
Occurrence
In B.C.: GSC cur. no. 68294, Mile Post 375 West section; GSC cur. nos. C-302187, 68204, both Mile Post 375 East section; GSC cur. nos. C-201916, C-201917, V-002607, V-003002, all North Tetsa Phosphate section; GSC cur. no. 74758, Mount Withrow section; GSC cur. no. V-002987, ARC Dawson 07-13-79-15W6 well; GSC cur. no. V-002955, Murphy Swan d-054-B/094-P-09 well; GSC cur. no. V-002981, Talisman Altares c-085-I/094-B-01 well; GSC cur. no. V-002983, Talisman Altares c-085-I/094-B-01 well; Tetsaoceras hayesi Zone (middle Anisian) to Tuchodiceras poseidon Zone (lower Ladinian). In Nevada: GSC cur. no. C-176339 (HB-159), McCoy Mine, New Pass Range; GSC cur. no. C-176331 (HB-105), Favret Canyon, Augusta Mountains; GSC cur. no. C-300229 (FH-50), Fossil Hill, Humboldt Range; Intornites mctaggarti Subzone (Acrochordiceras hyatti Zone, middle Anisian) to Frechites occidentalis Zone (upper Anisian).
Description
The platform of the P1 element is biconvex and widest at, or just posterior of, the midpoint. The platform margins taper evenly to both the anterior and posterior, leaving no free blade and no posterior platform brim. The posterior margin of the platform is pointed. Micro-reticulation is present on the platform margins. In side view, the element is arched and its platform is thin with upturned margins. The cusp is large, inclined, and terminal. The low carina maintains a uniform height in juveniles but appears to become lower with growth due to thickening of the platform margins. The denticles of the carina are discrete and upright to slightly inclined, and become more closely spaced in the middle third of the element. The keel is high and narrow, terminating in an open, subcircular basal loop that surrounds the terminal basal pit.
Etymology
From the Latin hastatus, meaning “armed with a spear,” in reference to the long, slender cusp that is diagnostic of the species.
Materials
388 specimens from B.C.; 40 specimens from Nevada.
Remarks
Morphotypes of Neogondolella ex gr. constricta have a similar carina to N. hastata, but possess a posterior platform constriction during at least the juvenile growth stage. Morphotypes of N. ex gr. regalis and N. ex gr. bulgarica have a much higher, more strongly fused carina than N. hastata. The lower Anisian species N. n. sp. sensu Orchard et al. (Reference Orchard, Grǎdinaru and Nicora2007) has a similar cusp and platform shape to N. hastata, but the former has a higher and more fused carina. Neogondolella hastata was illustrated by Mosher (Reference Mosher1973) as Neogondolella mombergensis, from the Tuchodiceras poseidon Zone in the lower Ladinian of Mount Withrow in B.C., indicating that the species ranges across the Anisian–Ladinian boundary.
Neogondolella indicta new species
Neogondolella indicta n. sp. (1–3) GSC type no. 131552, from the Toad Formation (Hollandites minor Zone, middle Anisian), GSC cur. no. C-201926, Mile Post 375 West; (4, 5), GSC type no. 131553; (6, 7) GSC type no. 131554 (holotype); both from the Toad Formation (H. minor Zone, middle Anisian), GSC cur. no. 46499, North Tetsa Hill; (8–10) GSC type no. 131555, from the Favret Formation (Nevadisculites taylori Zone, middle Anisian), GSC cur. no. C-159823, Favret Canyon, Nevada.
2014 Neogondolella n. sp. D; Reference GoldingGolding, p. 148, fig. 2.45, 1–9
Holotype
GSC type no. 131554 (Fig. 10.6, 10.7), from the Hollandites minor Zone (middle Anisian) of the Toad Formation, GSC cur. no. 46499, North Tetsa Hill section, B.C.
Diagnosis
A species of Neogondolella in which the segminiplanate P1 element has a broad, biconvex platform that is constricted and tapers asymmetrically in the posterior sixth of the element. A posterior denticle is always present and commonly offset from the carina. The carina is of moderate height, but appears low because of strongly upturned platform margins. The denticles are moderately fused, and a relatively high fixed blade that rises to the anterior is differentiated from the carina.
Occurrence
In B.C.: GSC cur. no. C-201926, Mile Post 375 West section; GSC cur. no. 46499, North Tetsa Hill section; GSC cur. nos. V-002607 and V-002615, both North Tetsa Phosphate section; Hollandites minor Zone (middle Anisian). In Nevada: GSC cur. no. C-176327 (HB-87), Black Horse Canyon, New Pass Range; GSC cur. no. C-176339 (HB-159), McCoy Mine, New Pass Range; GSC cur. nos. GSC C-159823 (HB-246) and C-159810 (HB-219), both Favret Canyon, Augusta Mountains; Unionvillites hadleyi Subzone (Acrochordiceras hyatti Zone, middle Anisian) to Pseudodanubites nicholsi Subzone (Nevadisculites taylori Zone, middle Anisian).
Description
The platform of the P1 element is biconvex, with its widest point at approximately the midpoint. The margins taper evenly to the anterior, terminating at or near the end of the element. The platform is constricted at the posterior in most specimens. The posterior platform margin is quadrate with a narrow platform brim present. Micro-reticulation is present on the platform margins. There are narrow, well-defined adcarinal grooves. In side view, the element is strongly arched, and the platform is thick with strongly upturned margins that sometimes slope unevenly to the anterior, forming a geniculation point. The cusp is small, often only slightly larger than adjacent denticles. A posterior denticle is always present, often larger than the cusp in moderately sized elements, and may be offset from the rest of the carina. The carina appears low and rises to the anterior to define a short fixed blade. The denticles of the carina are weakly fused throughout. The keel is low and wide, and terminates in a closed, subcircular to oval basal loop that surrounds the terminal basal pit.
Etymology
From the Latin indictus, meaning “inexpressible,” in reference to the subtle combination of morphological features that define this species.
Materials
Ten specimens from B.C.; 10 specimens from Nevada.
Remarks
Morphotypes of Neogondolella ex gr. constricta have a posterior platform constriction similar to N. indicta, but they also have a cusp that is distinctly larger than the other denticles of the carina, and the elements are narrower than those of N. indicta. Elements of N. unilobata (Gedik) and some morphotypes of N. ex gr. regalis have a similar platform shape to N. indicta, but all have a higher carina than the new species. Posterior platform constriction differentiates this species from N. hanbulogi (Sudar and Budurov).
Neogondolella panlaurentia new species
Neogondolella panlaurentia n. sp. (1–3) GSC type no. 120399, from the Blind Fiord Formation (Keyserlingites subrobustus Zone, Spathian), GSC cur. no. C-303122, Spath Creek, Canadian Arctic; (4–6) GSC type no. 131556 (holotype), from the Doig Formation (lower Anisian), GSC cur. no. V-002992, Petro-Canada Kobes d-048-A/094-B-09 well; (7, 8) GSC type no. 131557, from the Prida Formation (Japonites welteri Zone, lower Anisian), GSC cur. no. C-176327, Humboldt Range, Nevada.
2008 Neogondolella sp. C; Reference OrchardOrchard, p. 405, figs. 5.17–5.19
2014 Neogondolella n. sp. E—Reference GoldingGolding, p. 150, fig. 2.46, 1–3
Holotype
GSC type no. 131556 (Fig. 11.4–11.6), from the Lenotropites caurus Zone (lower Anisian) of the Doig Formation, GSC cur. no. V-002992, Petro-Canada Kobes d-048-A/094-B-09 well, B.C.
Diagnosis
A species of Neogondolella in which the segminiplanate P1 element has a platform that tapers abruptly to narrow flanges in the anterior third of the element, beyond weak geniculation points. The carina is low and fused in the middle third of the element but rises to the anterior to form a fixed blade. The posterior of the platform is subrounded and there is a narrow posterior brim. The cusp is large, terminal, and posteriorly inclined. The basal pit and loop are both narrow.
Occurrence
In B.C.: GSC cur. no. 99574, North Liard Section; GSC cur. no. 99581, South Liard section; GSC cur. no. V-002992, Petro-Canada Kobes d-048-A/094-B-09 well; Lenotropites caurus Zone (lower Anisian). In Canadian Arctic: GSC cur. no. C-303122, Spath Creek; Keyserlingites subrobustus Zone (Spathian). In Nevada: GSC cur. no. C-176327 (HB-92), northern Humboldt Range; Japonites welteri Zone (lower Anisian).
Description
The platform of the P1 element is widest at the midpoint. It is constricted in the anterior third, but continues to the end of the element, leaving no free blade. The subparallel platform margins taper to the posterior, forming a rounded posterior margin with a narrow platform brim. Micro-reticulation is present on the platform margins. In side view, the element is gently arched and the platform is thick with slightly upturned margins. The cusp is large and posteriorly inclined; there is no posterior denticle present. The carina is low in the middle of the element, becoming higher to the anterior, and the medial denticles of the carina are fused, becoming more discrete to the anterior. The keel is low and narrow, terminating in a closed, circular to sub-quadrate basal loop that surrounds the terminal basal pit.
Etymology
Derived from the occurrence of the species across Laurentia during the Triassic.
Materials
Four specimens from B.C.; two specimens from the Canadian Arctic; 16 specimens from Nevada.
Remarks
The anterior constriction of this species serves to separate it from most of its contemporaries. Neogondolella joanae Orchard from the Smithian (lower Olenekian) of B.C. is similar but has a more fused carina and a pointed posterior margin. Columbitella elongata (Sweet), from the Spathian, has more upturned margins. Some species of Quadralella are similar, in particular Q. acuminata (Orchard) from the Carnian of B.C.; other than by stratigraphic position, the latter species can be separated by its possession of a free blade, which is not present in N. panlaurentia.
Neogondolella tenera new species
Neogondolella tenera n. sp. (1–3) GSC type no. 131558; (7–9) GSC type no. 131559 (holotype); both from the Toad Formation (Eogymnotoceras deleeni Zone, upper Anisian), GSC cur. no. 99592, East Toad River; (4–6), GSC type no. 131560, from the Toad Formation (Hollandites minor Zone, middle Anisian), GSC cur. no. C-201926, Mile Post 375 West.
2014 Neogondolella n. sp. C; Reference GoldingGolding, p. 146, fig. 2.44, 1–9
Holotype
GSC type no. 131559 (Fig. 12.7–12.9), from the Eogymnotoceras deleeni Zone (upper Anisian) of the Toad Formation, GSC cur. no. 99592, East Toad River section, B.C.
Diagnosis
A species of Neogondolella in which the segminiplanate P1 element is relatively small, short, and broad, with platform margins that are subparallel to biconvex and taper strongly to the anterior. The platform narrows slightly in the posterior third of the element. The posterior platform margin is rounded, and a narrow posterior platform brim is present in adult specimens. The carina is moderately high and fused.
Occurrence
In B.C.: GSC cur. no. 99592, East Toad River section; GSC cur. no. C-201926, Mile Post 375 West section; GSC cur. no. V-002513, Shell Groundbirch 16-02-078-22W6 well; Hollandites minor Zone (middle Anisian) to Eogymnotoceras deleeni Zone (upper Anisian). In Nevada: GSC cur. no. C-201560 (HB-233), Muller Canyon, northern Humboldt Range; GSC cur. no. C-176333 (HB-111), southern Tobin Range; Favreticeras wallacei Subzone (Balatonites shoshonensis Zone, middle Anisian).
Description
The platform of the P1 element is biconvex to subparallel, with its widest point at or slightly anterior of the midpoint. Its margins taper strongly to the anterior end of the element but leave no free blade. To the posterior, the platform margins either taper evenly or show a weak narrowing before continuing to the end of the element, where they form a rounded posterior margin. A posterior platform brim is always present. Micro-reticulation is present on the platform margins. In side view, the element is evenly arched and the platform is thin with weakly upturned margins. The cusp is small and similar in size to the adjacent denticles. A posterior denticle that is similar in size to or smaller than the cusp is always present, although it becomes higher than the cusp in the largest specimens. The carina is of moderate height, becoming slightly higher to the anterior. The denticles of the carina are rounded, inclined and moderately fused, becoming more so in the largest specimens. The keel is low and narrow, terminating in a large, closed, oval basal loop that surrounds the terminal basal pit.
Etymology
From the Latin tener, meaning “dainty,” in reference to the diminutive size of the elements.
Materials
12 specimens from B.C.; 17 specimens from Nevada.
Remarks
This species is relatively short and broad compared with other species of Neogondolella from the Middle Triassic. Elements of N. indicta are similar but have a more differentiated anterior blade and a stronger posterior platform constriction. The narrow posterior platform differentiates N. tenera from N. hanbulogi.
Neogondolella vellicata new species
Neogondolella vellicata n. sp. (1–3) GSC type no. 131508, from the Toad Formation (Lenotropites caurus Zone, lower Anisian), GSC cur. no. C-201922, Mile Post 375 East; (4–6) GSC type no. 131561, from the Prida Formation (Acrochordiceras hyatti Zone, middle Anisian), GSC cur. no. C-176317, Straight Canyon, Nevada; (7–9), GSC type no. 131562 (holotype), from the Toad Formation (L. caurus Zone, lower Anisian), GSC cur. no. 99574, North Liard River.
1997 Neogondolella n. sp. M; Reference Orchard and TozerOrchard and Tozer, p. 681
2014 Neogondolella n. sp. B; Reference GoldingGolding, p. 144, fig. 2.43, 1–6
2014 Neogondolella n. sp. M sensu Orchard and Tozer; Reference Golding, Orchard and ZonneveldGolding et al., fig. 3, 19–21
Holotype
GSC type no. 131562 (Fig. 13.7–13.9), from the Grambergia nahwisi Subzone (Lenotropites caurus Zone, lower Anisian) of the Toad Formation, GSC cur. no. 99574, North Liard River section, B.C.
Diagnosis
A species of Neogondolella in which the segminiplanate P1 element has a platform that is widest in the posterior third. The platform is asymmetrical with a more convex outer margin and a straight to undulating inner margin; it tapers very close to the anterior of the element leaving a very short free blade. The carina is uniformly low, partially fused medially, and often laterally deflected at the posterior.
Occurrence
In B.C.: GSC cur. no. 99574, North Liard River section; GSC cur. no. C-201922, Mile Post 375 East section; Lenotropites caurus Zone (lower Anisian). In Nevada: GSC cur. no. C-176338 (HB-147), northern Humboldt Range; GSC cur. no. C-176317 (HB-25), Straight Canyon, northern Humboldt Range; Pseudokeyserlingites guexi Zone (lower Anisian) to Unionvillites hadleyi Subzone (Acrochordiceras hyatti Zone, middle Anisian).
Description
The platform of the P1 element is asymmetrical with its widest point in the posterior third; its margins taper to the anterior before narrowing abruptly close to the end of the element. The posterior platform margin is rounded and a very narrow posterior platform brim is present. Micro-reticulation covers much of the platform margins. In side view, the element is uniformly arched and its platform is thick with upturned margins. The cusp is small and sub-terminal; a posterior denticle is present, which is broader and higher than the cusp. The carina is moderately high, rising to the anterior, commonly with a laterally deflected posterior end. The denticles of the carina are strongly fused in the middle third, less so in the remainder, and are commonly flanked by relatively deep adcarinal furrows. The keel is low and wide, terminating in a closed, oval basal loop that surrounds the terminal basal pit.
Etymology
From the Latin vellico, meaning “to pinch,” in reference to the narrowing of the platform at the anterior end.
Materials
Seven specimens from B.C.; four specimens from Nevada.
Remarks
Morphotypes of Neogondolella ex gr. constricta have a posterior constriction, but do not have an anterior platform constriction, and have a lower, less fused carina. The platform of N. tenera tapers to the anterior but is not constricted, and it has a posterior platform constriction and more discrete denticles. N. indicta also differs in having a posterior platform constriction. N. panlaurentia has an anterior constriction that occurs much closer to the midpoint of the element. N. hanbulogi does not have an anterior platform constriction.
Acknowledgments
Constructive reviews by C. Henderson, an anonymous reviewer, and by Associate Editor S. Leslie helped to improve this manuscript. P. Krauss and H. Taylor assisted with processing samples and photographing specimens. Field assistance during the collection of new samples was provided by J.-P. Zonneveld and M. Balini, with logistical support provided by the Tetsa River Lodge. Conodonts from Nevada referred to in this paper were largely derived from matrix samples of ammonoid collections made by H. Bucher. Financial support for this study was provided in part by the Yukon Basins Project of the Geological Survey of Canada GEM Program, and in part by Geoscience B.C.
