A new species of Carlquistoxylon from the Early Cretaceous of Patagonia (Chubut province, Argentina):the oldest record of angiosperm wood from South America

NUNES, CRISTINA; PUJANA, ROBERTO ROMÁN; ESCAPA, IGNACIO HORACIO; GANDOLFO, MARÍA ALEJANDRA; CÚNEO, NÉSTOR RUBÉN

IAWA JOURNAL

INT ASSOC WOOD ANATOMISTS

Lugar: Leiden; Año: 2018 vol. 39 p. 406 - 426

0928-1541

An angiospermous wood from the Lower Cretaceous (upper Albian) of the Cerro Barcino Formation, Chubut Group, central Patagonia, Argentina, is described. It is significant as it is the oldest known angiosperm wood for South America.It has indistinct growth ring boundaries, vessels solitary and in radial multiples, simple perforation plates, alternate intervessel pits, vessel-ray parenchyma pits oval to horizontally elongated, heterocellular rays, non-septate fibres, axial parenchyma absent, and abundant tyloses. Because this Albian wood has non-septate fibres we assign it to Carlquistoxylon, even though it has a general combination of characters similar to that of Paraphyllanthoxylon, which has septate fibres. The number of vessels per radial multiple, vessel tangential diameter and frequency, vessel-ray parenchyma pitting, and absence of axial parenchyma distinguish the fossil described here from the only previously known species of Carlquistoxylon: Carlquistoxylon nacimientense; therefore, a new species is erected. Because of the close similarities between this new specimen and Paraphyllanthoxylon species, comparisons with all the species included in both genera are provided. Systematic affinities for this wood are discussed considering previous discussions for both Paraphyllanthoxylon and Carlquistoxylon affinities. This new specimen is the oldest described angiosperm wood in South America to date, and provides critical information on the diversity and morphology of Cretaceous angiosperms from the Southern Hemisphere.