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| Araucaria benignae L.Kunzmann, D.M.Conceição, Gobo, Nascimento, W.F.Silva Filho, M.E.P.Batista, Westerkamp, I.S.Carvalho & Iannuzzi, in Kunzmann, Conceição, Gobo, Nascimento, Silva Filho, Batista, Westerkamp, Carvalho et Iannuzzi, 2027. |
Highlights:
• Araucaria benignae sp. nov. from the Cretaceous Crato Fossil Lagerstätte is proposed.
• Fossils come from two distinct ethnostrata of the Crato Formation limestone.
• Ovuliferous cones are preserved as compressions and iron oxide replacements.
• Cuticle micromorphology of ovuliferous complexes and parastichy numbers are studied.
• Wood anatomical characters of the cone peduncle is described.
Abstract
The Crato Fossil Lagerstätte in the Mesozoic Araripe Basin in northeastern Brazil comprises one of the most important fossil floras in the Early Cretaceous (Aptian) of equatorial Gondwana, distinguished by its preservation, taxonomic diversity and evolutionary significance. Although the taxonomic diversity among gnetophytes and early angiosperms is remarkable, the most frequent macrofossil remains are foliage and reproductive organs of Araucariaceae. Similar to other late Mesozoic ecosystems, it has been assumed that fossil-species of this family were major constituents and canopy-forming trees of the past vegetation. Here, we formally describe ovuliferous cones from this unit and establish Araucaria benignae sp. nov. In order to overcome the uncontrolled fossil sampling in the outcrops of the Crato Formation, Santana Group, we tentatively reallocated the ovuliferous cone specimens to ethnostrata within the C6 carbonate unit of the lacustrine limestone section using the ethnostratigraphic approach. Specimens are probably derived from the “lajão dos sete cortes” and the “lajão branco” ethnostrata, which would mean a minimum time interval of the presence of the new fossil-species of about 79–310 ka. In addition, the previously known fossil-species of Araucariaceae from the Crato Formation flora are supplemented for first considerations about putative whole-plant reconstructions in this assemblage. Although a confident whole-plant association between Araucaria benignae sp. nov. and any of the three known araucariaceous foliage species cannot yet be established, shared epidermal characters suggest a possible affiliation with Brachyphyllum obesum and/or B. sattlerae, highlighting the potential of the Crato Fossil Lagerstätte for future whole-plant reconstructions of Cretaceous Araucariaceae.
Keywords: Araripe Basin; Cuticle micromorphology; Equatorial Gondwana; Ethnostratum approach; Ovuliferous cones; Parastichy numbers
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| External morphology of Araucaria benignae sp. nov., specimen MPSC PL 5937 (holotype). A: Pedunculate spherical ovuliferous cone in lateral view, densely and helically arranged ovuliferous complexes (OC); numbers indicate positions of samples for cuticle micromorphology studies. B: Close-up of A showing rounded apical part. C: Close-up of A showing dented base with short peduncle. D: Detail of B, densely arranged OC, apophyses with mostly partly broken processes, processes exclusively point towards cone apex, arrows indicate almost complete processes. E: Close-up of B with detail of abaxial surfaces of OC's apophyses, arrow points to longitudinally oriented rows of stomata (parallel lines of protruding dots). F: Detail of C showing peduncle (arrow), dotted lines trace to margins of two scale leaves. Scale bars: A, B, C, F: 10 mm; D, E: 5 mm. |
Systematic description
Subclass: Pinidae Cronquist, Takht. et W.Zimmerm. 1966 (Cronquist et al., 1966) [conifers]
Order: Araucariales Gorozh. 1904 (Gorozhankin, 1904)
Family: Araucariaceae Henkel et W.Hochst. 1865 (Henkel and Hochstetter, 1865)
Genus: Araucaria Juss. 1789 (Jussieu, 1789)
Araucaria benignae L.Kunzmann, D.M.Conceição, Gobo, NascimentoJr., W.F.Silva Filho, M.E.P.Batista, Westerkamp, I.S.Carvalho, et Iannuzzi sp. nov.
Etymology: After the Brazilian girl Benigna Cardoso da Silva called Menina Benigna (1928–1941), who was murdered in Santana do Cariri while defending herself against rape. Pope Franciscus beatified her in 2022.
Locality: Commercial limestone quarries between the cities Nova Olinda and Santana do Cariri, Nova Olinda County, Ceará State, Brazil.
Holotype: MPSC PL 5937; includes specimen, SEM stubs 01–03 from sample 2 (Fig. 5A) and LM slides 01–03 from samples 1–3, respectively.
Diagnosis: Spherical to ovoid pedunculate ovuliferous cones; apically obtuse to rounded; base often with central flat conical indentation. Peduncle foliated with Brachyphyllum-type leaves. Ovuliferous complexes arranged in 13 parastichies clockwise, 7 parastichies counterclockwise, 22 pseudo-parastichies. Ovuliferous complexes with narrow wing-like lateral parts and bulge-shaped distal apophysis with a spreading process directed towards the cone's apex. Free ligulate extension at the chalazal end of the seed short compared to seed length. Margin of ligulate extension composed of free finger-like cells. Abaxial epidermis of apophysis and apophysis‘process with numerous longitudinal rows of mostly monocyclic stomatal complexes with random pit orientation towards the process‘axis; complete epidermides non-papillate.
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| External morphology of Araucaria benignae sp. nov., and its fossils preserved as replacements, A–C: specimen MPSC PL 5930; D–H: specimen MPSC PL 5947p/cp (part/counterpart). A: Ovoid cone with acute apex and rounded base, outer surface abraded. B: Close-up of A, showing tangential sections of OC and yellowish circular parts of OC; cross-sections through chalazal end of seeds, demonstrating one-seeded OC; arrows indicate OC of which the outlines are demonstrated in C. C: Outlines of three OC are marked by densely dotted lines; wide-dotted lines within OC indicate the adaxial seeds. D, G: part and counterpart of ovoid cone specimen with acute apex and rounded-oblique base. E, H: Close-ups of D and G, respectively, showing mid to apical cone part with seeds (white arrows), seeds are partly filled with crystalline carbonate; dotted-line indicates outline of a single seed (same seed shown in both part and counterpart); black arrow indicates almost complete process of apophysis, which is adpressed and pointed towards cone apex. F: Cross-sectional view of peduncle scar at the part. Scale bars: A, E, F, G, H: 10 mm; B, C: 5 mm. |
Lutz Kunzmann, Domingas Maria da Conceição, William Vieira Gobo, Daniel Rodrigues do Nascimento Jr., Wellington Ferreira da Silva Filho, Maria Edenilce Peixoto Batista, Ana Paula de Assis Oliveira Westerkamp, Ismar de Souza Carvalho and Roberto Iannuzzi. 2027. New Seed Cones of Araucaria Juss. 1789 (Araucariaceae) in the Aptian Crato Fossil Lagerstätte, NE Brazil and considerations for whole-plant reconstruction. Review of Palaeobotany and Palynology. 356: 105716. DOI: doi.org/10.1016/j.revpalbo.2026.105716
