Fabaceae is one of the most diverse angiosperm families and is distributed across the globe in a variety of environments. The earliest evidence of the family, previous to this work, was from Paleogene sediments where it was found to be diverse in many fossil assemblages around the world. Here, we describe a fossil legume fruit from the Olmos Formation (upper Campanian) in northern Mexico. We designated the fossil fruit asLeguminocarpum olmensisCenteno-González, Martínez-Cabrera, Porras-Múzquiz et Estrada-Ruiz sp. nov., and related it with the Fabaceae family based on the presence of a dehiscent pod with two valves, an apex bearing stylar base, short stipe, and reticulated veins in the pericarp. We propose a new fossil species ofLeguminocarpumfor this fossil fruit. This fossil provides critical information on the long geologic history of Leguminosae around the world, significantly extending the record into the Cretaceous of Mexico.

A new record of fossil moss in Miocene amber from Chiapas, southern Mexico, is hereby presented. The fossil moss is assigned to the genus Hypnodontopsis Iwatsuki et Noguchi (Family Rhachitheciaceae) and characterized primarily by narrowly lanceolate to linear leaves arranged in rosettes, with erect costae, and short apiculate leaf tips, with upper cells larger than the lower cells. This sample, for which current worldwide distribution consists of at least three disjunct and geographically restricted occurrences, represents the first fossil record of the genus Hypnodontopsis in the Americas. While Hypnodontopsis is represented by five fossil species known from Eocene Baltic and Saxon amber, extant species are known from Asia, Africa and Mexico. The new fossil specimen most closely resembles the extant species Hypnodontopsis mexicana (Thér.) H. Robins, synonymous with the fossil species Hypnodontopsis conferta (Goeppert and Berendt) J.-P. Frahm. from Eocene Baltic amber. Hypnodontopsis mexicana ca... Resumen. Se presenta un nuevo registro de musgo fósil en ámbar miocénico de Chiapas, al sur de México. El musgo fósil está asignado al género Hypnodontopsis Iwatsuki et Noguchi (Familia Rhachitheciaceae). El ejemplar se caracteriza por presentar hojas estrechamente lanceoladas a lineares y dispuestas en rosetas, con costas erectas, y con ápices agudos, con células superiores más gruesas que las células inferiores. Este representa el primer registro fósil del género Hypnodontopsis para América, cuya distribución actual consiste en al menos tres ocurrencias separadas y geográficamente restringidas. Hypnodontopsis está representado por cinco especies fósiles de ámbar del Eoceno del Báltico y Sajonia, mientras que las especies actuales se encuentran en Asia, África y México. El nuevo espécimen fósil se asemeja a la especie actual Hypnodontopsis mexicana (Ther.) H. Robins., sinónimo de la especie fósil Hypnodontopsis conferta (Goeppert y Berendt) J.-P. Frahm. en el ámbar del Eoceno del Báltico. Hypnodontopsis ...

Premise of research. Over the past 3 decades, angiosperm woods have been reported from the Campanian to the Maastrichtian of southern Laramidia, including Coahuila and Chihuahua, Mexico; Big Bend National Park, Texas; and the San Juan Basin, New Mexico. Recent investigations of the upper Campanian (76.5 to >72.5 Ma) Jose Creek Member of the McRae Formation, south-central New Mexico, indicate an abundance of well-preserved silicified woods, representing one of the most diverse Cretaceous wood floras in the world. In this report, we describe four new angiosperm wood types. Methodology. The fossil woods described here were collected from the upper Campanian of south-central New Mexico, along the northeastern flank of the Caballo Mountains and in the adjacent Cutter Sag, and were studied using thin sections. The potential affinities of these McRae woods were determined by comparison with fossil and extant woods. Pivotal results. The woods reported here comprise one magnoliid and three eudicots with varying levels of comparability to extant taxa. Laurinoxylon rennerae sp. nov. belongs to Lauraceae and has a combination of features found in multiple extant genera variously referred to as Cinnamomeae Nees, Laureae Maout & Decaisne, or Lauroideae Burnett/core Lauraceae. Turneroxylon newmexicoense gen. et sp. nov. is a eudicot with many similarities to Dilleniaceae but differs in having narrower rays. Mcraeoxylon waddellii gen. et sp. nov. has a suite of features seen in several families of Malpighiales, Myrtales, and Oxalidales. McRae angiosperm wood type 1 has a suite of features found in genera of Dilleniales, Ericales, and Malpighiales. Conclusions. All wood types, with the exception of M. waddellii, have minimum axis diameters of >10 cm (12–50 cm), indicating that they represent trees. This reinforces previous evidence for the presence of small to large angiosperm trees in the Jose Creek Member and underscores the importance of woody angiosperms in vegetation of the southern Western Interior during the Campanian-Maastrichtian.

Premise of research. In the past two decades, numerous aquatic ferns related to Marsileaceae from the Upper Cretaceous have been described. Most fossils resembling Marsilea L. but lacking reproductive structures have been included in the fossil genus Marsileaceaephyllum. Here we describe a new species of the aquatic fern genus Marsilea from the Olmos Formation (upper Campanian), northern Mexico, that is represented by leaves, rhizomes, and a sporocarp. This new fossil represents the first unequivocal record of the extant genus Marsilea worldwide from the Late Cretaceous. Methodology. The fossils we describe in this article were collected from sediments of the Olmos Formation, Coahuila, Mexico. The samples were identified by direct comparison with fossils from other localities and extant species. Pivotal results. The aquatic fern described here consists of leaves that are composed of four opposite leaflets in a cruciform arrangement. The fossil leaflets can be sessile or attached to a short petiolule, and their base is straight to cuneate. The leaflet apex can be obtuse and/or round, and the margin is entire but is sometimes slightly wavy toward the apex of the leaflet. The leaflets have straight venation, dichotomous with anastomoses (reticulate) throughout the leaflet. The areoles are polygonals and fusiform, and they fuse to form a marginal vein. Small sporocarp without teeth, oblong in lateral view. The combination of the features discussed above supports the creation of a new species of Marsilea from the upper Campanian of northern Mexico. Conclusions. The new species of Marsilea reported here represents the first record of the genus from the Cretaceous and provides additional evidence that aquatic plants such as Marsilea—as well as Salvinia, Dorfiella, Pistia, Nymphaceae, and Nelumbonaceae—were an important element of the flora preserved in the Olmos Formation.

En México la diversidad de hepáticas es muy importante en zonas tropicales y subtropicales, desafortunadamente es poco lo que se ha descrito formalmente con base en material fósil. En este estudio se documenta por primera vez el género Frullania en el ámbar miocénico de Chiapas, sur de México. Esta planta se caracteriza por una ramificación irregular, terminal del tipo Frullania. Tiene hojas con inserción íncuba, alternas, distantes a contiguas, ovadas a orbiculares, con margen entero y liso, y sus ápices redondeados. Posee lóbulos alargados con forma de saco, dos veces más largos que anchos y anfigastrios bífidos y obovados con rizoides dispuestos en mechones en su base. Este registro de Frullania indica que la flora fósil de Chiapas también estaba integrada por hepáticas y que este género formó parte de la diversidad tropical y subtropical del sur de México desde el Mioceno Temprano.