Fossil fruits formerly described as cashews from the Oligocene of Peru are reinvestigated based on the original specimens and newly collected materials. The recovery of an outer spiny layer, preserved in the sedimentary molds surrounding the locule casts, indicates that these disseminules do not represent Anacardium. Imagery from nano-CT scans of the specimens documents a distinctive morphology which does not resemble any fruits or seeds of Anacardiaceae. We describe the morphology in more detail and reassign the fossils to an extinct genus, Pseudoanacardium gen. nov., of uncertain familial affinity. Pseudoanacardium peruvianum (Berry) comb. nov. was a prominent member of the Belén carpoflora, which also included palms plus Annonaceae, Euphorbiaceae, Humiriaceae, Leeaceae, Icacinaceae, Rutaceae and Vitaceae.
The Mastixiaceae (Cornales) were more widespread and diverse in the Cenozoic than they are today. The fossil record includes fruits of both extant genera, Mastixia and Diplopanax, as well as several extinct genera. Two of the fossil genera, Eomastixia and Mastixicarpum, are prominent in the palaeobotanical literature, but concepts of their delimitation have varied with different authors. These genera, both based on species described 93 years ago by Marjorie Chandler from the late Eocene (Priabonian) Totland Bay Member of the Headon Hill Formation at Hordle, England, are nomenclaturally fundamental, because they were the first of a series of fossil mastixioid genera published from the European Cenozoic. In order to better understand the type species of Eomastixia and Mastixicarpum, we studied type specimens and topotypic material using x-ray tomography and scanning electron microscopy to supplement traditional methods of analysis, to improve our understanding of the morphology and anatomy of these fossils. Following comparisons with other fossil and modern taxa, we retain Mastixicarpum crassum Chandler rather than transferring it to the similar extant genus Diplopanax, and we retain Eomastixia bilocularis Chandler [=Eomastixia rugosa (Zenker) Chandler] and corroborate earlier conclusions that this species represents an extinct genus that is more closely related to Mastixia than to Diplopanax.
A new occurrence of fossil butternut is recognized based on a permineralized highly scabrate walnut from the middle Miocene of western Washington, USA. The specimen fits the circumscription of Juglans bergomensis (Balsalmo Crivelli) Massalongo, a species that was widespread in Europe and Asia during the Neogene. The occurrence near Brady, Washington, supplements the previously recognized occurrence from Banks Island, Canada, indicating a distribution in mid-latitude western North America as well as Europe and Asia during the Miocene.
Morphology and anatomy of the extinct angiosperm fruit, Porosia verrucosa (Lesqueruex) Hickey, are documented in detail based on various modes of preservation including molds, casts, and permineralizations from more than seventy localities in the late Cretaceous and Paleocene. The fruits are schizocarpic with paired unilocular, single-seeded mericarps seated on a prominent gynophore with an hypogynous perianth borne on a long pedicel. The most distinctive feature of these fruits is the regularly spaced cylindrical intrusions over the surface of the endocarp. These are interpreted to represent oil cavities similar to those common in the fruits of extant Rutaceae. The oldest known occurrences of P. verrucosa are from the Late Cretaceous (Campanian to Maastrichtian) of western North America, but the genus traversed Beringia and became widespread in the Paleocene both in Asia (Kazakhstan, Amur Region, and Koryak Highlands), and North America (Montana, North Dakota, Wyoming, Colorado, Oregon, Washington, Alberta, Saskatchewan). It extended to the late Paleocene in the Rocky Mountain and Great Plains region, and appears to have become extinct near the Paleocene-Eocene boundary.
Dashrath Kapgate, Steven R. Manchester and Wolfgang Stuppy
A permineralized fruit from the latest Cretaceous of central India is recognized as a member of the malpighialean family Phyllanthaceae. The fruit is a tricarpellate, septicidal capsule 2.8 mm in diameter possessing two ellipsoidal seeds per locule. The pericarp includes two main layers, each uniseriate and composed mainly of columnar cells. This fruit, named Phyllanthocarpon singpurensis gen. et sp. nov., confirms the presence of Phyllanthaceae in India ca 66 million years ago, well prior to its tectonic fusion with Eurasia, and is an early record for the euphorbioid clade in Malpighiales.
Terry A. Lott, Steven R. Manchester and Sarah L. Corbett
The plant fossils of Alum Bluff, northwestern Florida, provide a unique insight into the rarely preserved Miocene flora of the eastern United States. A century has passed since the introductory treatment on the fossil leaf flora of Alum Bluff. More specimens have accumulated over the past two decades, allowing for an updated evaluation of the megafossil flora following a recent study of the palynoflora. The strata consisting of poorly consolidated sand and siltstones with intervening clay layers, here recognized as the Fort Preston Formation of the Alum Bluff Group, are considered to be of Barstovian age (16.3–13.6 Ma), based on co-occurring mammalian remains. Here we recognize 36 kinds of leaves and 10 kinds of fruits and seeds, giving a minimum estimate of at least one fungus, one fern, one gymnosperm, 38 angiosperms and 7 unknowns. We also report one new species and two new combinations. These taxa augment those already reported based on pollen from the same strata, allowing us to portray the vegetation as elm-hickory-cabbage palm forest occurring near the coastline in a deltaic, pro-deltaic, or intertidal shore face environment. The results of a climate analysis of the Alum Bluff flora, using leaf margin and leaf area, give estimates of 19.0°C mean annual temperature and 116.0 cm mean annual precipitation.
Steven R. Manchester, Kathleen B. Pigg and Melanie L. Devore
Two fossil fruit types and at least one fossil leaf type representing Trochodendraceae are recognized from the middle Miocene Cascadia flora of western Oregon, USA. Trochodendron rosayi sp. nov., known also from the middle Miocene of eastern Oregon and northern Idaho, is based on long-pedicelled, apically dehiscent capsular fruits with 7-9 persistent outcurved styles, very similar to the extant monotypic east Asian species T. aralioides. Concavistylon kvacekii gen. et sp. nov. is named for a racemose infructescence bearing shortly pedicellate, apically dehiscent capsules with 4 to 5 persistent incurved styles arising from the basal 1/3 of the fruit. Leaves associated at the Moose Mountain locality are recognized as Trochodendron postnastae sp. nov. They have basally acrodromous venation with a prominent midvein bracketed by a pair of strongly ascending basal secondaries and are thought to correspond to the T. rosayi fruits. These new occurrences demonstrate that greater diversity was present among fossil Trochodendraceae than previously recognized during the Miocene in western North America.
Bruce H. Tiffney, Steven R. Manchester and Peter W. Fritsch
We describe two new species of Symplocos (Symplocaceae) from the early Miocene Brandon Lignite Flora of Vermont, USA. The endocarps of Symplocos laevigata (Lesq.) comb. nov. are most similar in morphology and anatomy to those of the extant species S. tinctoria of southeastern North America and S. wikstroemiifolia of eastern Asia, both of S. sect. Hopea, and to those of several species of S. sect. Lodhra, endemic to eastern Asia; they are also somewhat similar to those of S. minutula of the Tertiary of Europe. The endocarps of Symplocos hitchcockii sp. nov. are most similar in morphology and anatomy to those of living members of S. sect. Lodhra, and are also somewhat similar to fossil S. incurva of the Tertiary of Europe. This report extends the fossil record of Symplocos endocarps to eastern North America and underscores the mixed mesophytic to subtropical nature of the Brandon flora.
Fabiany Herrera, Steven R. Manchester, Mónica R. Carvalho, Carlos Jaramillo and Scott L. Wing
Extant Neotropical rainforests are well known for their remarkable diversity of fruit and seed types. Biotic agents disperse most of these disseminules, whereas wind dispersal is less common. Although wind-dispersed fruits and seeds are greatly overshadowed in closed rainforests, many important families in the Neotropics (e.g., Bignoniaceae, Fabaceae, Malvaceae, Orchidaceae, Sapindaceae) show numerous morphological adaptations for anemochory (i.e. wings, accessory hairs). Most of these living groups have high to moderate levels of plant diversity in the upper levels of the canopy. Little is known about the fossil record of wind-dispersed fruits and seeds in the Neotropics. Six new species of disseminules with varied adaptations for wind dispersal are documented here. These fossils, representing extinct genera of Ulmaceae, Malvaceae, and some uncertain families, indicate that wind-dispersed fruit and seed syndromes were already common in the Neotropics by the Paleocene, coinciding with the early development of multistratal rainforests. Although the major families known to include most of the wind-dispersed disseminules in extant rainforests are still missing from the Paleogene fossil record of South and Central America, the new fossils imply that anemochory was a relatively important product and/or mechanism of plant evolution and diversification in early Neotropical rainforests.
Steven R. Manchester, Lina B. Golovneva, Dmitry D. Sokoloff and Else Marie Friis
Floral and fruit morphology of the early eudicot Ranunculaecarpus quinquecarpellatus Samyl. is described based on details from sectioning and microscopy of the permineralized type material from the Albian Buor-Kemyus Formation of the Zyryanka coal basin. Serial sections confirmed most of the originally described characters but revealed additional information, including hypogynous perianth and several stamens with in situ pollen. Each fruit consists of five free follicles inserted on a short receptacle. Follicles are elongate, with a dorsal keel, ventral suture and an attenuate apex, and are thin-walled, with two rows of small seeds in marginal placentation. The seeds are anatropous, ovoid, 1.3–1.7 in length, with an exotesta of cells that are rounded-hexagonal in surface view. The hypogynous perianth is composed of several free tepals. The stamens are short, with tetrasporangiate, dithecal anthers dehiscing by longitudinal slits. Pollen in situ is 18–20 mm long, 13–15 mm in equatorial diameter, with uncertain aperture configuration and a loose reticulum supported by narrow, widely spaced columellae. The combination of macromorphological characters support possible affinity to extant Ranunculaceae. However, Ranunculaecarpus is distinguished from modern members of the family by the persistence of the perianth in fruit, a smaller number of stamens (ca 10) than is typical, and pollen that is unlike that of any extant genera. Given that there are also similarities with Saxifragales, the systematic affinities of Ranunculaecarpus remain uncertain.