La Anita Megafloral level 1 - Sample 104 (Cretaceous of Argentina)
Where: Santa Cruz, Argentina (50.5° S, 72.6° W: paleocoordinates 52.5° S, 62.4° W)
• coordinate stated in text
When: Chorrillo Formation, Early/Lower Maastrichtian (70.6 - 66.0 Ma)
Environment/lithology: terrestrial; cherty/siliceous mudstone
• It consists of siliciclastic mudstones with pedogenic features and abundant plant debris
Size classes: macrofossils, mesofossils, microfossils
Preservation: trace
Collection methods: Palynomorphs were extracted and concentrated from fragments of rocks obtained from both Megafloral levels by treating them with HCl 38% and HF 45% using standard palynological techniques (Phipps and Playford, 1984) and also without prior crushing, and then sieved using 20 mm and 10 mm meshes, as well as 80 mm and 500 mm meshes, to obtain the larger fractions, i.e., organic macrofossils (sensu Pole, 2007). Individual cuticles and other remains were also collected from these fractions under a binocular microscope and mounted on microscope slides. The organic residues were sieved using an 80 mm mesh and mounted on permanent slides, and then explored for cuticles and other remains. Treatments of rocks from Megafloral level 2 with HCl 38% and HF 45% did not result in recoverable organic remains.
•All studied specimens are housed in the Museo Regional Padre Jesús Molina (Río Gallegos, Santa Cruz Province), under MPM-PB (hand samples) and MPM-Pal (Palynological slides and SEM stubs) acronyms.
Primary reference: E. I. Vera, V. S. Perez Loinaze, D. Moyano-Paz, M. D. Coronel, M. Manabe, T. Tsuihiji, and F. E. Novas. 2022. Paleobotany of the uppermost Cretaceous Chorrillo Formation, Santa Cruz Province, Argentina: insights in a freshwater floral community. Cretaceous Research 138(105296):1-23 [E. Vlachos/E. Vlachos]more details
Purpose of describing collection: taxonomic analysis
PaleoDB collection 231725: authorized by Evangelos Vlachos, entered by Evangelos Vlachos on 30.08.2023, edited by Matthew Clapham
Creative Commons license: CC BY (attribution)
Taxonomic list
• The studied sample preserves a rich and diverse palynoflora composed of a total of 15 spore species, 23 angiosperm pollen grains, and 19 gymnosperm pollen grains
Show authors, comments, and common names
| unclassified | |
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Cyanobacteria "cf. Microcystis sp. in McCarthy et al 2021" Stanier 1973 Colonial non-filamentous coccoid algae (MPM-Pal 21834-10)
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| Orthothecimorpha | |
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Costatheca striata The genus Costatheca is generally interpreted as angiosperm seed cuticles (Kutluk and Hills, 2017). Nevertheless, its affinities are discussed. Some authors relate this genus to mossess (Miner, 1935), or consider it as incertae sedis plant remains (Gunther and Hills, 1972; Knobloch, 1986, 1990)
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| Insecta | |
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Coelolepida indet. Nielsen and Kristensen 1996 moth MPM-Pal 21835- 3:W34/1, MPM-Pal 21835-23:W55/0, MPM-Pal 21835- 22:R52/2,MPM-Pal 21835-20:Z47/3. MPM-Pal 21835-22: G55/0; MPM-Pal 2183-21: E42/3
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Chironomidae indet., Tanypodinae indet., Orthocladiinae "indet. 1", Orthocladiinae "indet. 2", "Heptagyini indet." = Heptagyiini
Orthocladiinae "indet. 1" Lenz 1921 non biting midge MPM-Pal 21835-24: M31/0, MPM-Pal 21835-3: P46/4
"Heptagyini indet." = Heptagyiini Brundin 1966 non biting midge MPM-Pal 21835-9:E34/4, MPM-Pal 21835-19: V34/4
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Fungi indet. Fungal remains are diverse in the assemblage, and include didymospores (Fig. 7F), phragmospores (Fig. 7G, J-M), microthyriaceous ascocarps (Fig. 7H, I) and hyphae (Fig. 7N).
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| Cingutriletes | |
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Cingutriletes australis Archangelsky 1972 | |
| Magnoliopsida | |
Polycolpites sp., Psilatricolporites cf. complanatius, Tricolporites sp., Rhoipites cf. alveolatus, Rhoipites minusculus, Dicotetradites sp., Rousea patagonica
Polycolpites sp. Couper 1953
Tricolporites sp. Cookson 1947
Rhoipites cf. alveolatus Couper 1953
Rhoipites minusculus Archangelsky 1973
Dicotetradites sp. Couper 1953
Rousea patagonica Archangelsky 1973 | |
| Dicotyledoneae | |
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Ericipites scabratus Harris 1965 heather | |
| Angiospermae | |
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Nymphaeaceae "single star-shaped sclereid" Salisbury 1805 water lily | |
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Monocots "morphotype CUT-CHO-3" The third morphotype, CUTeCHOe3, has longitudinally oriented stomata concentrated in rows, and as some large fragments are preserved devoid of stomata, it was probably part of a non-amphistomatic leaf. Epidermal cells are elongate or somewhat isodiametric, with slightly sinuous anticlinal walls, and presents rows of two cells commonly recognizable by thickened longitudinal anticlinal walls, with thin anticlinal walls contained within these rows (secondary anticlinal division?). The stomatal complex is monocyclic, paratetracytic, subsidiary cells are probably thinner periclinal walls than in epidermal cells, and the guard cells are flanked on the inside by a thick ridge of cuticle (Fig. 5HeK).
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Liliacidites cf. kaitangataensis Couper 1953 | |
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Arecipites cf. subverrucatus Mildenhall and Pocknall 1989 palm
Arecipites minutiscabratus Mc Intyre 1968 palm | |
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Eudicots "morphotype CUT-CHO-1" Doyle and Hotton 1991 CUTeCHOe1 consist of cuticles not divided into costal and intercostal zones, with sparse stomata not aligned. Epidermal cells of this morphotype are isodiametric, and each one bears a single smooth papilla. Stomatal complex is not clearly observable, but guard cells are flanked on the inside by a thick ridge of cuticle (Fig. 5D, E)
Eudicots "morphotype CUT-CHO-2" Doyle and Hotton 1991 The second morphotype, CUTeCHOe2, is represented by a single cuticle fragment bearing sparsely distributed non-aligned stomata. Epidermal cells are isodiametric to elongate, irregularly distributed, with straight to slightly curved anticlinal walls. The stomatal complex in this cuticle is monocyclic and paracytic,with guard cells flanked on the inside by a thickened ridge. Subsidiary cells are winglike, highly elongated tangential to the stomata (Fig. 5F, G).
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Polypodiidites sp. Potonié 1966 | |
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Peninsulapollis truswelliae Dettmann and Jarzen 1988
Beauprea elegansiformis Cookson 1950 | |
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Tubulifloridites lilliei Farabee and Canright 1986 daisy | |
Phrixipollenites infrulus, Podocarpidites marwikii, Podocarpidites cf. langii, Podocarpidites sp., Podocarpidites otagoensis, Podocarpidites major, Podocarpidites elegans, Podocarpidites exiguus, Podocarpidites ellipticus, Podocarpidites herbstii, Podocarpidites verrucosus, Podocarpidites cf. microreticuloidata, Phyllocladidites mawsonii, Microcachryidites antarcticus
Phrixipollenites infrulus Haskell 1968 podocarp
Podocarpidites marwikii podocarp
Podocarpidites cf. langii podocarp
Podocarpidites sp. Cookson 1947 podocarp
Podocarpidites otagoensis Couper 1953 podocarp
Podocarpidites major Couper 1953 podocarp
Podocarpidites elegans Romero 1977 podocarp
Podocarpidites exiguus Harris 1965 podocarp
Podocarpidites ellipticus Cookson 1947 podocarp
Podocarpidites herbstii Burger 1966 podocarp
Podocarpidites verrucosus Volkheimer 1972 podocarp
Podocarpidites cf. microreticuloidata Cookson 1947 podocarp
Phyllocladidites mawsonii Cookson 1947 podocarp
Microcachryidites antarcticus Couper 1953 podocarp | |
| Algae | |
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Ovoidites parvus Nakoman 1966
Ovoidites spriggii Cookson and Dettmann 1959 | |
| Lycopodiopsida | |
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Ceratosporites equalis Cookson and Dettmann 1958 clubmoss | |
| Cycadopites | |
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Cycadopites follicularis Wilson and Webster 1946 | |
| Concavissimisporites | |
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Concavissimisporites sp. Delcourt and Sprumont 1955 | |
| Ginkgoopsida | |
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Vitreisporites signatus Leschik 1956 | |
| Lusatisporis | |
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Lusatisporis sp. Krutzsch 1963 | |
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Tracheophyta "morphotype CUT-CHO-4" CUTeCHOe4 groups several cuticles consisting of glabrous isodiametric polygonal epidermal cells, which are irregularly distributed (Fig. 5L). The morphology and size of the cells (15e35 mm) closely compares with the one observed in the studied Nuphar? sp. 2 seeds, and may belong to the same biological entity. Nevertheless, cuticles with similar epidermal cells can be found in other plant groups.
Tracheophyta "morphotype CUT-CHO-5" Finally, CUTeCHOe5 contains cuticles with glabrous elongate polygonal epidermal cells, with thick straight anticlinal walls (Fig. 5M, N). The lack of stomata and diagnostic features precludes their referral to any plant group, as similar epidermal cells are seen in different not-related plant groups, including ferns, conifers and angiosperms.
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| Psilatricolpites | |
"Tricolpites cf. inargutus" = Psilatricolpites inargutus
"Tricolpites cf. inargutus" = Psilatricolpites inargutus Archangelsky 1973 | |
| Equisetopsida | |
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Foraminisporis wonthaggiensis Dettmann 1963 | |
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Araucariacites australis Cookson 1947
Dilwynites tuberculatus Harris 1965
Classopollis sp. Pflug 1953 | |
| Pteridopsida | |
| Polypodiopsida | |
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Polypodiopsida "Isolated leptosporangium (MPM-Pal 21835-K)" Cronquist et al. 1966 Isolated leptosporangium (MPM-Pal 21835-K. consists of isolated leptosporangia, 150e210 mm in diameter, devoid of spore content, the largest having at least 13 cells conforming the annulus (Fig. 7A), representing another evidence of terrestrial ferns in the assemblage (along with the isolated pinnule here described, and fern spores identified here and in Novas et al., 2019).
Biretisporites spp. Delcourt et al. 1963 | |
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Leptolepidites verrucatus Couper 1953 | |
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Gleicheniidites sp. Dettmann 1963 | |
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Baculatisporites comaumensis Potonie 1953
Baculatisporites turbioensis Archangelsky 1972 | |
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Laevigatosporites ovatus Wilson and Webster 1946 | |
| Constantinisporis jacquei | |
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Constantinisporis jacquei Belsky et al. 1965 | |
| Tricesticillus americanus | |
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Tricesticillus americanus Stough 1968 | |