TR-J Cover.p65 - City of St. George

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from the Middle Jurassic of England. The British cones are about the same size as the ones described here, have a similar wedge-shape, and bear a single broad seed (Cleal and Rees, 2003). The poorly preserved cone scale complexes described from Scotland as A. millerii Seward (1911) resemble somewhat those considered here except that the seeds are relatively narrow compared to the seeds of the new species. In the Southern Hemisphere, similar cone scales have been illustrated by Stockey (1994) from the Jurassic of New South Wales, Australia. Triassic Araucaria-like cone scales are much less common than Jurassic forms. Probably the best documented such fossils are the conescale complexes assigned to Araucarites charcotii Harris (1935) from the latest Triassic (Rhaetic) of East Greenland. Although they are nearly the same age, they differ significantly from the specimens described here. First, the fossils from Greenland are more or less diamond-shaped with long, tapered distal halves that are delicate, wedge-shaped, and sturdy with a short apical beak on the rounded apical margin in the present material. Also, the ovules in the Greenland specimens dropped before the cone scales were preserved, in contrast to A. stockeyi where most ovules are retained. Furthermore, the ovules are much larger (5-8 mm wide) in the new species than those in the Greenland specimens. The latter were probably only about 4-5 mm wide since the shallow depression in which they were located is the width of several of the cone scales. The two incomplete cones here tentatively assigned to this species (see Figs. 3J, K) resemble slightly the cone described as Aliostrobus traversei Ash (1999) from the Upper Triassic of east-central New Mexico. The plications found in the cone scales in the cones from both localities are particularly noteworthy. Discussion: It appears that the seeds of Araucarites stockeyi were often retained on the scale complexes at shedding as in section Eutacta. The absence of ovules in the cones and their small size maybe an indication that these two fossils are immature compared to the dispersed forms. The falling away of the seed in one specimen of the new species (Figs. 3C, D) has also been reported by Stockey (1975) in Araucaria mirabilis (Spegazzini) Calder (1953) from the Jurassic of Argentina. The presence of what most certainly are araucarian cone-scale complexes at the SGDS in the very Early Jurassic indicates that the origins of the family must lie earlier in time, such as in the Late Triassic. Interestingly, however, such fossils have not yet been identified with certainty in the underlying Chinle Formation of Late Triassic age that is widely distributed in the southwestern United States. However, the majority of plant fossils that are known in the Chinle occur in the lower part that is assigned to the Late Carnian/Early Norian. Thus it may be that the earliest araucarians lie in the slightly younger (Late Norian/ Rhaetic) parts of the Chinle and equivalent strata in the Southwest and elsewhere. Family Uncertain Genus Saintgeorgeia new genus Type species: Saintgeorgeia jensenii n. sp. Derivation of name: After the city of Saint George where the St. George Dinosaur Discovery Site at Johnson Farm is located. Diagnosis: Leafy shoot forming flattened spray, ultimate branches in a single plane, leaves scale-like, opposite on penultimate branches, spirally arranged on ultimate branches. Staminate cones attached to ends of ultimate branches. Geologic range: Early Jurassic in southwestern Utah. Saintgeorgeia jensenii new species Figures 4A-G, 5B, C Holotype: SGDS.627A, B. Paratypes: SGDS.517A. Derivation of name: From the name of the present owner of the type locality, Paul Jensen. 417 Diagnosis: Leafy shoot, forming more or less flat sprays, penultimate branches straight, 3-5 mm wide, more than 17 cm long, ultimate branches slender, 2-3 mm wide, 3-5 cm long, opposite to subopposite, arising from axils of lateral leaves on penultimate branches. Leaves scale-like, single-veined, arising oppositely at intervals of about 5 mm, spreading, forwardly directed, falcate, recurved, distally free, acutely pointed, base expanded, decurrent. Leaves on penultimate branches in one plane, 5 mm long, 10 mm wide at base, leaves on ultimate branches 3 mm long, 10 mm wide at base and appear spirally arranged. Cones about 3 cm long, 1 cm wide, attached to the ends of ultimate branches, staminate, sporophylls spirally arranged, closely attached. Description: This species is represented by several dozen, generally poorly preserved specimens. Some of the best preserved of them are shown in Figure 4. The oppositely arranged leaves are clearly evident on the lateral margins of most specimens (see Figs. 4B, C, D, G), but there is no evidence of them on the upper sides of the branches. The attachment of the staminate cone-bearing ultimate branches to the penultimate branches is shown on several specimens (e.g., Figs. 4B, D). The cones are too poorly preserved to provide detailed description of sporophyll morphology. In addition, the microspores of this species as well as the ovulate cones and seeds are unknown. Comparisons: The ultimate branches with attached cones are similar to Elatides, but differ by having more flattened leaves with broader basal attachment. Spirally arranged leaves occur on both penultimate and ultimate branches in Elatides, whereas they are only present on the ultimate branches of Saintgeorgeia. Also, the male cones are smaller, nearly one-half the size, in Elatides than in Saintgeorgeia. Discussion: The leafy shoots of this species appear to have been FIGURE 4. Saintgeorgia jensenii n. gen, n. sp. from the SGDS. A, SGDS.627B, longest specimen of the penultimate branch which shows several ultimate branches and the typical short aciculate leaves. B, SGDS.517A, penultimate branch showing two ultimate branches (a) terminating in cones (b). C, SGDS.517C, counterpart of the lower part of the penultimate branch in B illustrating opposite aciculate leaves. Note the twisted appearance of the leaves. D, SGDS.517A, an ultimate branch arising from the axil of a leaf (a) on a penultimate branch and terminating at the base of a cone (b). E, SGDS.517A, apical region of a cone of this species. F, SGDS.517B, ultimate branch with attached base of cone. G, SGDS.561A, long penultimate branch showing a single ultimate branch on the right side and typical aciculate leaves.
418 FIGURE 5. Sketches of selected foliage at the Johnson Farm locality. A, SGDS.558.I, the fragment of a fossil leaf in Figure 6C compared with a sketch of the upper portion of a leaflet of Podozamites distans given by Harris (1935). B, SGDS.517A, a short length of a branch showing small spirally arranged leaves. C, SGDS.517A, fertile branch of Saintgeorgia jensenii arising from the axil of a leaf on a penultimate branch of the species. Drawn from the specimen in Figure 4D. fairly robust. Since the penultimate branches that have been found are more or less straight and thick, it is probable that they were rather rigid. The opposite leaves and ultimate branches indicate that the leafy shoots formed flat sprays, perhaps similar to those of some species in the Cupressaceae. Most of the known staminate cones of this species are attached to ultimate shoots (Figs. 4A, B, D, F, 5B, C), suggesting that they were retained for sometime after formation. Genus Pagiophyllum Heer, 1881 Discussion: Pagiophyllum is one of a series of morphogenera based on leaf characters that are used for mainly Mesozoic sterile coniferous foliage. As now employed, Pagiophyllum is distinguished from other genera of coniferous foliage by having uni-veined leaves that are narrowly triangular in plan view and that are less than five times their width in length. In addition, the leaves are helically arranged and diverge from the parent stem at a low angle. Geologic range: Late Triassic into the Cretaceous. Pagiophyllum sp. Figure 6D Material: SGDS.491. Description: This species is represented by a single slender axis about 1 mm wide and 10 cm long that bears more or less alternate lateral branches that are 10-30 mm long and appear flexible. The axis and the lateral branches are usually concealed by small, helically arranged leaves. The leaves are lanceolate with obtuse to acutely pointed apices. The free parts of the leaves are typically about 2 mm long and about 1 mm wide at the widest near the base. The surfaces of the leaves are smooth. Cuticle and cones are not preserved. Discussion: Comparisons between this specimen and previously described species of Pagiophyllum are essentially impossible because of the lack of cuticle on the specimen. The species described by Harris (1979) from the Middle Jurassic Yorkshire of England, for instance, is based largely on cuticle, which allows for more accurate determination of its species but does not allow for meaningful comparisons with Pagiophyllum sp. Genus Milnerites new genus Type species: Milnerites planus n. sp. Derivation of name: After Andrew R.C. Milner, City Paleontologist, St. George, Utah. Diagnosis: Flattened leafy shoots, leaves arranged in two ranks on opposite sides of axes, leaves decurrent, triangular to falcate in lateral view, containing a single vein. Geologic range: Early Jurassic in southwestern Utah. Milnerites planus new species Figure 6A-B Material: SGDS 513A, 558A. Derivation of name: From the Latin, planus, flat, level, in reference to the appearance of the leafy shoot of this species. Diagnosis: Shoots robust, flattened, single plane, leaves close, 2- ranked, opposite to subopposite, decurrent, coriaceous, triangular to falcate in lateral view, 3-5 mm long, 1-4 mm wide at base, apex acute, occasionally slightly curved, attached by entire base, abaxial surface convex, somewhat rounded, but not keeled; single vein, immersed, continues to near apex. Discussion: Specimens are incomplete. They are not typical conifer-type foliage and, in some cases, they appear to be more fern-like in outline. The fact that the shoots are flattened with the leaves attached in two ranks on opposite sides of axes, rather than arranged in a helical, whorled, or decussate pattern, is rather unique. It is similar in this context to some foliage of Metasequoia, but differs by not being petiolate FIGURE 6. Milnerites planus (A, B), cf. Podozamites (C), and Pagiophyllum sp. (D) from the SGDS. A-B, In these specimens of Milnerites planus (A is SGDS.558A; B is SGDS.513A), the triangular-shaped leaves are clearly opposite and single veined. The upper leaf shoot in A is not connected with the specimen in the lower part of the specimen, although it represents the same species. C, SGDS.558I, fragment of a leaflet that compares fairly closely with Podozamites. Note the parallel veins in the specimen that are typically of this genus. Compare with the drawing in Figure 5A. D, SGDS.491, leafy shoot of Pagiophyllum sp.
Page 1 and 2: 414 Harris et al., eds., 2006, The
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Page 7: 420 Lockley, M.G., Kirkland, J.I. a

TR-J Cover.p65 - City of St. George

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