Classostrobus doylei, a new cheirolepidiaceous cone with in situ pollen from the Figueira da Foz Formation (lower Aptian – upper Albian), western Portugal
{"title":"Classostrobus doylei, a new cheirolepidiaceous cone with in situ pollen from the Figueira da Foz Formation (lower Aptian – upper Albian), western Portugal","authors":"","doi":"10.1016/j.cretres.2024.106028","DOIUrl":null,"url":null,"abstract":"<div><div>The genus <em>Classostrobus</em> was established to accommodate unattached <em>Classopollis</em>-containing cones. It is noteworthy that <em>Classopollis</em> as a whole shows significant variation in morphological structure, and male cones bearing <em>Classopollis</em> pollen grains are rarer than vegetative organs of cheirolepidiaceous conifers. A new cheirolepidiaceous microsporangiate cone, <em>Classostrobus doylei</em>, containing <em>Classopollis triangulus</em> pollen grains is described for the first time based on a single specimen from sedimentary rocks exposed in the Carregueira open-cast clay pit complex close to the small village of Juncal, in the Estremadura region(Lusitanian Basin, western Portugal). The plant-bearing horizon from Carregueira is included in the basal part of the Famalicão Member of the Figueira da Foz Formation, considered to be of late Aptian – early Albian age. The new microsporangiate cone is small, about 2.0 mm long and 1.5 mm wide, ovoid in shape and of typically coniferous structure, probably belonging to <em>Pseudofrenelopsis zlatkoi</em>. The male cone consists of about 16 peltate, imbricated microsporophylls of deltoid shape. Each sporophyll is composed of a stalk and deltoid head showing abaxially 4–5 ovoid pollen sacs. The marginal parts of the sporophylls display long and unicellular trichomes. The observed <em>in situ</em> pollen grains are triangular to subcircular in outline, 16–28 μm in diameter, with an equatorial girdle, subequatorial rimula, proximal trilete scar and a distal cryptopore. The pollen ultrastructure is typical for <em>Classopollis</em>, except for the destroyed condition of the exine. The <em>in situ</em> pollen grains under study are consistent with the data on known dispersed <em>Classopollis triangulus</em>.</div></div>","PeriodicalId":55207,"journal":{"name":"Cretaceous Research","volume":null,"pages":null},"PeriodicalIF":1.9000,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Cretaceous Research","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0195667124002015","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The genus Classostrobus was established to accommodate unattached Classopollis-containing cones. It is noteworthy that Classopollis as a whole shows significant variation in morphological structure, and male cones bearing Classopollis pollen grains are rarer than vegetative organs of cheirolepidiaceous conifers. A new cheirolepidiaceous microsporangiate cone, Classostrobus doylei, containing Classopollis triangulus pollen grains is described for the first time based on a single specimen from sedimentary rocks exposed in the Carregueira open-cast clay pit complex close to the small village of Juncal, in the Estremadura region(Lusitanian Basin, western Portugal). The plant-bearing horizon from Carregueira is included in the basal part of the Famalicão Member of the Figueira da Foz Formation, considered to be of late Aptian – early Albian age. The new microsporangiate cone is small, about 2.0 mm long and 1.5 mm wide, ovoid in shape and of typically coniferous structure, probably belonging to Pseudofrenelopsis zlatkoi. The male cone consists of about 16 peltate, imbricated microsporophylls of deltoid shape. Each sporophyll is composed of a stalk and deltoid head showing abaxially 4–5 ovoid pollen sacs. The marginal parts of the sporophylls display long and unicellular trichomes. The observed in situ pollen grains are triangular to subcircular in outline, 16–28 μm in diameter, with an equatorial girdle, subequatorial rimula, proximal trilete scar and a distal cryptopore. The pollen ultrastructure is typical for Classopollis, except for the destroyed condition of the exine. The in situ pollen grains under study are consistent with the data on known dispersed Classopollis triangulus.
期刊介绍:
Cretaceous Research provides a forum for the rapid publication of research on all aspects of the Cretaceous Period, including its boundaries with the Jurassic and Palaeogene. Authoritative papers reporting detailed investigations of Cretaceous stratigraphy and palaeontology, studies of regional geology, and reviews of recently published books are complemented by short communications of significant new findings.
Papers submitted to Cretaceous Research should place the research in a broad context, with emphasis placed towards our better understanding of the Cretaceous, that are therefore of interest to the diverse, international readership of the journal. Full length papers that focus solely on a local theme or area will not be accepted for publication; authors of short communications are encouraged to discuss how their findings are of relevance to the Cretaceous on a broad scale.
Research Areas include:
• Regional geology
• Stratigraphy and palaeontology
• Palaeobiology
• Palaeobiogeography
• Palaeoceanography
• Palaeoclimatology
• Evolutionary Palaeoecology
• Geochronology
• Global events.