The "medullosalean forest" at the Lloyd Cove Seam (Pennsylvanian, Sydney Coalfield, Nova Scotia, Canada)

Self Cite

The global data base for detached trigonocarpalean (Medullosales) ovules is large, and they are found in the Euramerican and Cathaysian fl oral provinces, from the Pennsylvanian to early Permian Periods. Despite the abundance, little is still known on what parts of the parent plant the ovules were borne, or in what arrangement they were attached. New data are presented for organically paired, suggested triplet, and axially or cauline borne trigonocarpalean ovules from the Sydney Coalfi eld, Nova Scotia. RÉSUMÉLa base de données mondiale des ovules trigonocarpaléens (Medullosales) détachés est imposante; on les trouve dans les provinces fl oristiques euraméricaine et cathaysienne de la période du Pennsylvanien au Permien précoce. Malgré cette abondance, on sait encore peu de choses sur les parties de la plante-mère où sont nés les ovules, ou selon quelle disposition ils étaient fi xés. De nouvelles données sont présentées au sujet d'ovules trigonocarpaléens biologiquement jumelés, présumés triplets et axiaux ou caulinaires du terrain houiller de Sydney, en Nouvelle-Écosse.[Traduit par la rédaction.]

Section: Introductionmentioning

confidence: 87%

Section: -213mentioning

confidence: 98%

Note on different kinds of attachments in trigonocarpalean (Medullosales) ovules from the Pennsylvanian Sydney Coalfield, Canada

Zodrow

2004

Self Cite

“…The occurrence of downward-recurved petioles and resin rodlets in the wood strongly suggests that this tree was a medullosan pteridosperm (Zodrow 2002(Zodrow , 2003Laveine and Behlis, 2007). Furthermore the intimate facies association of this tree with foliage of Macroneuropteris scheuchzeri in the same plane as the petioles suggest an identity with this morphospecies.…”

Section: Trees In Growth Positionmentioning

confidence: 93%

A Macroneuropteris scheuchzeri tree preserved in growth position in the Middle Pennsylvanian Sydney Mines Formation, Nova Scotia, Canada

Falcon-Lang

2009

Fossil plants preserved in growth position provide important insights into the architecture and ecology of ancient plants. Here I describe an upright tree of Macroneuropteris scheuchzeri rooted above the Point Aconi Coal in the Middle Pennsylvanian Sydney Mines Formation of Nova Scotia -the first example of an autochthonous pteridosperm described in the literature. The fossil tree has a sharply tapering trunk surrounded in its lower part by a large number of downward-recurved senescent petioles, which form a skirt. Petioles borne in an upright or horizontal position, interpreted as fronds that were still photosynthetically active when buried, are confined to the uppermost preserved part of the tree. Adapted to growth in rapidly aggrading coastal wetlands, the skirt of Macroneuropteris scheuchzeri probably acted to prop up the trunk while additionally trapping large mounds of mud around the base of the tree and stabilizing coastal wetlands. The tree had a sprawling habit and a maximum height of about 2 m. Similar, but smaller, trees found in adjacent beds probably represent juvenile specimens of the same species. rÉSUMÉLes végétaux fossiles conservés dans leur position de croissance fournissent des renseignements précieux sur l'architecture et l'écologie des plantes anciennes. Je décris dans le présent document un Macroneuropteris scheuchzeri droit enraciné au-dessus de charbon de Point Aconi dans la Formation du Pennsylvanien moyen de Sydney Mines, en Nouvelle-Écosse -premier exemple de ptéridosperme autochtone décrit dans les ouvrages. L'arbre fossile possède un tronc nettement effilé entouré dans sa partie inférieure d'un grand nombre de pétioles sénescents recourbés vers le bas, qui forment une jupe. Des pétioles en position verticale ou horizontale, interprétés comme des frondes qui étaient encore actives sur le plan photosynthétique au moment de l'enfouissement, sont confinés à la partie la plus élevée de l'arbre conservée. Adaptée à la croissance dans les milieux humides côtiers d'alluvionnement rapide, la jupe du Macroneuropteris scheuchzeri servait probablement à maintenir le tronc et permettait en même temps d'emprisonner de gros monticules de boue autour de la base de l'arbre et de stabiliser les milieux humides côtiers. L'arbre, qui avait tendance à s'étendre, atteignait une hauteur maximale d'environ deux mètres. Des arbres semblables mais plus petits découverts dans des couches adjacentes représentent probablement de jeunes spécimens de la même espèce. [Traduit par la redaction]

“…The roof shale is notable for its rich, well preserved plant-fossil assemblage, among which are taxonomically significant seed-fern associations of the Ca-nadian Carboniferous coalfields. They include a foliage-frond-petiole-trunk-ovule association (Zodrow 2002;Zod-row et al 2013;Zodrow 2015, 2016;Zodrow and Mastalerz 2017).…”

Section: Methodsmentioning

confidence: 99%

Novel preservation state of Dolerotheca (medullosalean male organ) from the Late Pennsylvanian of the Sydney Coalfield, Nova Scotia, Canada

Zodrow¹,

Mastalerz²

2019

Self Cite

A new preservation state for the medullosalean male organ Dolerotheca is exemplified by a detached 31-mm sideritic mold with intact coalified compression from shale from the roof of a coal seam in the Sydney Coalfield, Cape Breton Island, Nova Scotia, Canada. Clearly recognizable in the specimen is the quadripartite campanulum. Furthermore, maceration yielded significant internal information on acellular, cuticular, stomatiferous and pubescent surfaces, and prepollen sacs with grains. Stomata are rare and of the cyclocytic type. The rectangular prepollen sacs occur as doubly paired rows of sporangia that are radially arranged, and contain ellipsoidal prepollen grains 400−520 μm long and circular prepollen grains 330−460 μm in diameter. The approximate ratio of circular to ellipsoidal grains is 1:2. Regardless of shape, the prepollen grains are attributable to the genus Monoletes. The circular grains bear vestigial trilete marks. Infrared-based functional-group chemistry distinguishes between the cover-type compression state and prepollen grains on the basis of higher aliphatic and oxygenated group contents in the grains. In summary, the specimen represents a novel state of nodular preservation with intact compression. Although the specimen is attributed to the genus Dolerotheca, specific assignment is not possible because of limited preservation and material.