Astroniumxylon, Schinopsixylon , and Parametopioxylon n. gen. fossil woods from upper Cenozoic of Argentina: taxonomic revision, new taxon and new records

FRANCO, M. JIMENA; MOYA, ELIANA; BREA, MARIANA; MARTÍNEZ MARTÍNEZ, CAMILA

JOURNAL OF PALEONTOLOGY

PALEONTOLOGICAL SOC INC

Año: 2020 vol. 94 p. 185 - 201

0022-3360

This paper presents new descriptions of Anacardiaceae fossil woods from the Ituzaingó Formation(late Cenozoic) at the Toma Vieja, Curtiembre, and Arroyo El Espinillo localities, Argentina.We describe eight silicifiedwoods assigned to four different species in three genera, one of which, Parametopioxylon crystalliferum n. gen. n. sp., isnew. Similarities between these three genera and the six Anacardiaceae species previously recorded from the late Cenozoicin northeastern Argentina are investigated using multivariate analysis techniques (correspondence and cluster analysis).Our study is based on 33 characters scored for 17 fossil specimens (10 Astroniumxylon Brea, Aceñolaza, and Zucol2001; five Schinopsixylon Lutz, 1979; and two Parametopioxylon n. gen.) and four extant species (Astronium balansaeEngl., Astronium urundeuva Engl., Schinopsis balansae Engl., and Metopium sp.). Our main goal is to determine thewood anatomical features useful for distinguishing among these species. Results of the multivariate analyses supportthe previous classification where Schinopsixylon is distinguished from Astroniumxylon by having exclusively paratrachealaxial parenchyma, ≥30% multiseriate rays, and multiseriate rays that are ≥5 cells wide and commonly 301?400μm in height. Additionally, we propose that Schinopsixylon heckii Lutz, 1979 is synonymous with S. herbstii Lutz,1979. A diagnostic key for the fossil species studied is given.Wood anatomy of Anacardiaceae fossil woods from Argentina(late Cenozoic) suggests a warm, dry to semi-humid climate for this region, supporting previous studies.