Fossil moonseeds from the Paleogene of West Gondwana (Patagonia,Argentina)

Premise of the Study

The fossil record is critical for testing biogeographic hypotheses. Menispermaceae (moonseeds) are a widespread family with a rich fossil record and alternative hypotheses related to their origin and diversification. The family is well‐represented in Cenozoic deposits of the northern hemisphere, but the record in the southern hemisphere is sparse. Filling in the southern record of moonseeds will improve our ability to evaluate alternative biogeographic hypotheses.

Methods

Fossils were collected from the Salamanca (early Paleocene, Danian) and the Huitrera (early Eocene, Ypresian) formations in Chubut Province, Argentina. We photographed them using light microscopy, epifluorescence, and scanning electron microscopy and compared the fossils with similar extant and fossil Menispermaceae using herbarium specimens and published literature.

Key Results

We describe fossil leaves and endocarps attributed to Menispermaceae from Argentinean Patagonia. The leaves are identified to the family, and the endocarps are further identified to the tribe Cissampelideae. The Salamancan endocarp is assigned to the extant genus Stephania. These fossils significantly expand the known range of Menispermaceae in South America, and they include the oldest (ca. 64 Ma) unequivocal evidence of the family worldwide.

Conclusions

Our findings highlight the importance of West Gondwana in the evolution of Menispermaceae during the Paleogene. Currently, the fossil record does not discern between a Laurasian or Gondwanan origin; however, it does demonstrate that Menispermaceae grew well outside the tropics by the early Paleocene. The endocarps’ affinity with Cissampelideae suggests that diversification of the family was well underway by the earliest Paleocene.     

Origin and evolution of the Pseudorhyncocyonidae,a European Paleogene family of insectivorous placental mammals

Two new species of pseudorhyncocyonid, Fordonia lawsoni sp. nov. and Leptictidium prouti sp. nov. from the UK earliest Eocene, described here, are older than any previously recorded member of the family. They are represented by teeth from numerous loci, which allow a better understanding of the sparsely known dentitions of currently known pseudorhyncocyonids. This facilitates the recognition of two further species of Leptictidium, L. listeri sp. nov. from the Middle Eocene of Germany and L. storchi sp. nov. from the Late Eocene of France. Study of occlusal relationships also helps to fill gaps in our knowledge of missing tooth loci. Cladistic analysis of pseudorhyncocyonids with their previously judged closest relatives, the Leptictidae, Pantolesta and Palaeanodonta, shows that two European species, Diaphyodectes prolatus and Palaeictops? levei, formerly thought to be leptictids, are instead primitive pseudorhyncocyonids, extending the range of the family further back in time to the Middle Paleocene. P? levei is placed in the new genus Phakodon gen. nov. The analysis also shows that the Pseudorhyncocyonidae are sister group to the other three groups combined and that family‐level differentiation in this probable clade took place as early as the earliest Paleocene.     

The long‐term history of dispersal among lizards in the early Eocene: new evidence from a microvertebrate assemblage in the Bighorn Basin of Wyoming,USA

Abstract: Early Eocene mammal faunas of North America were transformed by intercontinental dispersal at the Paleocene–Eocene boundary, but lizard faunas from the earliest Eocene of the same area were dominated by immigrants from within the continent. A new lizard assemblage from the middle early Eocene of Wyoming sheds light on the longer‐term history of dispersal in relation to climate change. The assemblage consists of three iguanid species (including two new species possibly closely related to living Anolis), Scincoideus, ‘Palaeoxantusia’, four anguids, two species of an undescribed new anguimorph clade, Provaranosaurus and a varanoid (cf. Saniwa). Most North American glyptosaurin glyptosaurines are now referred to Glyptosaurus, and Glyptosaurus hillsi is given a new diagnosis. Scincoideus is otherwise known only from the mid‐Paleocene of Belgium, and the specimens described here are the first to document intercontinental dispersal to North America among lizards in the early Eocene. Like in mammals, some immigrant lizard lineages first appearing in the Bighorn Basin in the earliest Eocene persisted in the area long after the Paleocene–Eocene thermal maximum, but other immigrants appear to have been restricted to the Paleocene–Eocene thermal maximum.     

Paleogene fossil fruits of Stephania (Menispermaceae) from North America and East Asia

Stephania Loureiro is a large genus within Menispermaceae, with approximately 60 extant species naturally distributed in tropical to subtropical areas in Asia and Africa, and a few in Oceania. This genus possesses highly characteristic endocarps that facilitate identification of extant and fossil specimens. Here, we report some well-preserved fossil fruits of Stephania from North America and East Asia. The specimens indicate the endocarps were bony or woody with an obovate to obovate-rotund outline and a horseshoe-shaped locule. The endocarp length varies from 4.7 to 8.3 mm, and width from 3.7 to 7.0 mm. The endocarp has a clear foramen in the central area and is surrounded by a keel with ribs running along the dorsal surface. Only one lateral crest develops on each side of the endocarp. Two new species are recognized: Stephania wilfii Han & Manchester sp. nov. from the Paleocene to Eocene of Wyoming (USA), and Stephania jacquesii Han & Manchester sp. nov. disjunct between the late Eocene of Oregon (USA) and the late Oligocene of Guangxi Province (China). In addition, on the basis of more detailed morphological comparative analyses, we transfer the fossils formerly treated as Diploclisia auriformis (Hollick) Manchester from the early Eocene of London Clay, and the middle Eocene of Alaska and Oregon to Stephania auriformis (Hollick) Han & Manchester comb. nov. These fossil materials indicate a broader biogeographic distribution for the ancestors of extant Stephania lineages. This finding enhances our knowledge of the taxonomic and morphological diversity of Stephania and provides new evidence concerning its phytogeographic history.     

New macrostomatan snake from the Paleogene of northwestern Argentina

The lower Eocene Lumbrera Formation in Salta province, northwestern Argentina, outstands for providing snake remains from a non-Patagonian Paleogene site. The material consists of articulated precloacal vertebrae that represent a new medium-sized macrostomatan snake, namely Amaru scagliai nov. gen., nov. sp. The vertebral characters of Amaru scagliai nov. gen., nov. sp., suggest affinities with advanced clades, which is consistent with the recognition of derived macrostomatans in the early Paleocene of Bolivia and early Eocene of Brazil. The new snake confirms the presence of macrostomatan snakes in South America as early as the Eocene and suggests that the southern continents may have played an unsuspected role in the origin and evolution of advanced macrostomatans during the earliest Cenozoic.     

Phytogeographic implications of fossil endocarps of Menispermaceae from the Paleocene of Colombia

? Premise of the study: Fossil leaves of Menispermaceae were previously described from the Paleocene of Colombia. Because of strong homoplasy of leaf characters, the fossils could not be placed more specifically within recognized clades, and additional data were needed to specify intrafamilial and paleogeographic relationships during the Paleocene. ? Methods: Fossil endocarps of Menispermaceae were collected from the Cerrejón Formation, the recently discovered Bogotá flora, and Wyoming (～60 Ma). We surveyed the endocarp morphology of almost all extant genera, conducted character optimization, a molecular scaffold analysis, and critically reviewed the related fossil genera. ? Key results: Parallel syndromes of fruit characters have appeared in unrelated clades of the family according to current phylogenetic reconstructions. However, mapping selected endocarp characters across those clades that contain horseshoe-shaped endocarps facilitates identification and phylogenetic assessment of the fossils. Three fossil species are recognized. One of them belongs to the extant genus Stephania, which today grows only in Africa and Australasia. Palaeoluna gen. nov. is placed within the pantropical clade composed of extant Stephania, Cissampelos, and Cyclea; this morphogenus is also recognized from the Paleocene of Wyoming. Menispina gen. nov. shows similarity with several unrelated clades. ? Conclusions: The new fossils from Colombia reveal a complex paleobiogeographic history of the recognized clades within Menispermaceae, suggesting a more active exchange among neotropical, paleotropical, North American, and European paleoforests than previously recognized. In addition, the new fossils indicate that neotropical forests were an important biome for the radiation and dispersal of derived lineages in Menispermaceae after the Cretaceous-Paleogene boundary.     

Late Eocene leaves of Nageia (section Dammaroideae) from Maoming Basin,South China and their implications on phytogeography

A new species of Nageia, Nageia maomingensis sp. nov., is described from the Late Eocene of Maoming Basin, Guangdong Province, South China. According to its cuticular characteristics, the present fossil species is assigned to N. sect. Dammaroideae, showing the most resemblance to the extant species N. motleyi (Parl.) de Laub. At present, this section is mainly distributed in the Pacific islands region from South Asia to New Guinea. The discovery of N. maomingensis demonstrates that plants of this section inhabited South China at least by the Eocene. The distribution and living habitat of extant N. sect. Dammaroideae imply that South China was warmer during the Late Eocene than today, and may represent one of the centers for early diversification of Nageia and its section Dammaroideae during the Eocene. In addition, we postulate that plants of sect. Dammaroideae migrated southward in response to climate cooling after the Eocene.     

Small Celastraceae and Polygonaceae twigs from the Upper Cenozoic (Ituzaingó Formation) of the La Plata Basin,Argentina

Two new wood types from the Late Cenozoic of the Ituzaingó Formation, La Plata Basin, Northeast Argentina add to our knowledge of South American Cenozoic plants. The materials were preserved by siliceous cellular permineralization, and they were prepared for microscopic examination by surface polishing and in thin sections. The anatomy of these new species was described. The relationship and comparison with the nearest living relatives (NLRs) are discussed. Maytenoxylon perforatum Franco gen. and sp. nov. is described as the first fossil wood referable to Celastraceae from South America. This new fossil species is related to extant Maytenus Molina. The other fossil twig, Ruprechtioxylon breae Franco sp. nov., has features of the Polygonaceae family and particularly resembles the extant specie Ruprechtia laxiflora Meisn. The occurrence of these fossil woods in south-eastern South America suggests that a relatively warm and dry to seasonally dry climate prevailed over this region of Gondwana during the Upper Cenozoic. It also provides new evidence for the hypothesis of the more wide distribution of Seasonally Dry Tropical Forest (SDTF) during the Upper Cenozoic.     

A new species of the catfish Nigerium from the Palaeogene of the Tilemsi Valley,Republic of Mali

Abstract: The phosphate deposits of the Tilemsi Valley, Republic of Mali, West Africa, are well known for their rich fossil vertebrate fauna including fishes, crocodilians, snakes and mammals. Despite this, the exact age of the deposits has been in some doubt. Here, a new species of catfish, Nigerium tamaguelense sp. nov., is described from the phosphate deposits at Tamaguélelt, Tilemsi Valley, based on a large collection of 29 well‐preserved crania. The crania are compared with the known species of Nigerium, N. wurnoense White and N. gadense White. The genus Nigerium is reviewed and now placed in the family Claroteidae based on a combination of three derived characters. Nigerium is compared with other African fossil catfish genera and the fossil record of catfish families in Africa is reviewed. The new evidence presented here shows the Claroteidae to be the earliest occurring catfish family in Africa. Evidence is also presented for an Early Eocene age for the phosphate deposits at Tamaguélelt.     

An early Oligocene fossil acorn,associated leaves and pollen of the ring‐cupped oaks (Quercus subg. Cyclobalanopsis) from Maoming Basin,South China

The ring‐cupped oaks (Quercus subg. Cyclobalanopsis) characterized by united and concentric ring‐cupped acorns, are mainly distributed in broad‐leaved evergreen forests in tropical and subtropical regions of East and Southeast Asia. Their geological history has been traced from the middle Eocene to Pleistocene. Most reports of the subgenus have been on the basis of leaves, whereas the acorns or cupules, more valuable evidence for the inter‐ and intrageneric classifications, have been relatively poorly documented. Here, we describe a new species, Quercus shangcunensis sp. nov., based on a ring‐cupped fossil acorn and pollen on the acorn, as well as Quercus sp. associated leaves, recovered from the early Oligocene Shangcun Formation of Maoming Basin, Guangdong Province, South China. The morphological and anatomical structures of these fossils confirm their attribution to the subg. Cyclobalanopsis. Quercus shangcunensis sp. nov. represents the world's first Oligocene fossil acorn and the earliest fossil acorn in China for the subgenus, indicating that the subg. Cyclobalanopsis arrived in the low latitude area of South China at least by the early Oligocene. Our fossil provides evidence that the subgenus was present in one of its modern distribution centers in the Oligocene, suggesting that the modern distribution patterns of the subg. Cyclobalanopsis most likely originated during or prior to the Oligocene.     

The first species of Hapalodectes (Mesonychia,Mammalia) from the middle Paleocene of China (Qianshan Basin,Anhui Province) sheds light on the initial radiation of hapalodectids

A lower jaw of the mesonychian Hapalodectes is reported from Nongshanian sediments (Upper Doumu Formation; middle Paleocene) of the Qianshan Basin (Anhui Province, China). The fragmentary mandible is only the third specimen of Hapalodectidae discovered in Paleocene deposits, and the first in south east China; it is moreover the oldest, the two other specimens having been found in Gashatan (late Paleocene) localities. The premolars and molars of the new fossil are morphologically similar to Hapalodectes dux (late Paleocene of Mongolia), which has been considered to be the most primitive hapalodectid, but their relative proportions recall H. paleocenus and the Eocene Hapalodectes species. As a result, the fossil described herein appears to be different from the other previously described species of Hapalodectes in being morphologically intermediate between H. dux and the other Hapalodectes species, notably the Bumbanian Hapalodectes hetangensis and H. huanghaiensis from China; it is thus identified as a new species, Hapalodectes lopatini (possibly a male individual). Its discovery is important because it sheds light on the initial radiation of hapalodectids. The presence of one primitive hapalodectid in Mongolia previously suggested the Mongolian Plateau as the centre of origination of this carnivorous family, but the discovery of H. lopatini in older sediments from south‐east China challenges this hypothesis. In the earliest Eocene, Hapalodectes dispersed from Asia to North America; this event being part of the ‘East of Eden’ dispersals. This event resulted in the geographical separation of two distinct Hapalodectes groups, in North America and south‐eastern China respectively.     

New records of archaic ungulates from the Lower Eocene of Sanshui Basin,Guangdong, China

Phenacolophidae is a group of little known archaic ungulates from the Late Paleocene to Middle Eocene of Asia. Its phylogenetic relationships with other altungulates have remained uncertain, partly because most phenacolophids are represented by poorly preserved material. Here we report a new phenacolophid, Sanshuilophus zhaoi gen. et sp. nov., from the Lower Eocene Huayong Formation of the Sanshui Basin, Guangdong, China. Although still fragmentary, the new specimens show that the new taxon is characterised by relatively large body size (except for Zaisanolophus), sub-molariform premolars, relatively higher bilophodont molars that lack the mesostyle, and tooth enamel microstructure with true prisms and typical Hunter-Schreger bands (HSB). With the new specimens and a review of the published phenacolophid material, we are able to provide an alternative identification for the tooth loci for the type specimen of Phenacolophus and further present an emended diagnosis for Phenacolophidae. The tooth morphology and enamel microstructure provide new evidence to support the notion that phenacolophids differ from species of Embrithopoda in having low-crown teeth, considerably slanting lophids, distinct paralophids and lacking the arsinoitheriid radial enamel. Phenacolophidae should not be included in Tethytheria but probably represent a stem group for altungulates, if not for all archaic ungulates.     

New carnivoraforms from the early Eocene of Europe and their bearing on the evolution of the Carnivoraformes

Two new mammalian carnivoraform species, Uintacyon hookeri sp. nov. and Quercygale smithi sp. nov., are described from the early Eocene of Europe. U. hookeri sp. nov. is recorded in Mutigny (MP8 + 9, PE IV), Avenay (MP8 + 9, PE V), Brasles, Condé‐en‐Brie (MP8 + 9) and Cuis (MP 10), while Q. smithi sp. nov. comes from Mutigny and Mancy (MP10). Because the two species are not recorded in earliest Eocene localities such as Dormaal and Le Quesnoy (MP7, PE I), it is proposed that they dispersed after the main phase of the Mammal Dispersal Event. U. hookeri sp. nov. supports the existence of terrestrial connections with North America, while Q. smithi sp. nov. implies possible faunal exchange with Asia. This evidence for the evolution of the Carnivoraformes supports: (1) a rapid decrease in their diversity after the Mammal Dispersal Event; and (2) the existence of a mammal turnover event in Europe during the early Eocene. The discovery of a new species of Quercygale, which is generally considered as the closest carnivoraform to the crown‐group Carnivora, shows that the genus had already lost the M₃ by the early Eocene and supports an important, but very poorly known, radiation of the carnivoraforms at least during the earliest early Eocene.     

湖北丹江口早始新世梳趾鼠类一新属及伴生哺乳动物化石

描述了湖北省丹江口市均县镇一始新世化石点的3种哺乳动物化石,其中包括梳趾鼠类一新属种：林氏汉南鼠（新属、新种）Hannanomys lini gen. et sp. nov.。根据林氏汉南鼠与其他梳趾鼠类性状对比及该地点动物群组合特点推测其时代为早始新世晚期,与产于玉皇顶组中段的王家营大尖地方动物群的时代相当。该化石点是李官桥盆地中汉江南岸早始新世化石地点的首次发现,它的认定对在此地区寻找古新统/始新统界线有重要意义。     

Provannid and provannid‐like gastropods from the Late Cretaceous cold seeps of Hokkaido (Japan) and the fossil record of the Provannidae (Gastropoda: Abyssochrysoidea)

A fauna of provannid and provannid‐like shells is described from Upper Cretaceous seep carbonates in Hokkaido, Japan. We describe two new provannid species, Provanna tappuensis sp. nov. and Desbruyeresia kanajirisawensis sp. nov. , with preserved protoconchs of unquestionable provannid type with decollate apex. This material confirms the occurrence of Provannidae as early as the Middle Cenomanian. We also describe Hokkaidoconcha gen. nov. and a new family Hokkaidoconchidae fam. nov. , with two named species, H. hikidai sp. nov. and H. tanabei sp. nov . Hokkaidoconchidae are possibly related to the Provannidae, judging from a similar, but not decollate larval shell, although the juvenile teleoconch whorls differ in being of a general cerithimorph appearance and the details of the aperture are unknown. Furthermore, we review the published fossil record of Provannidae and Abyssochrysidae, and we consider that in those older than the Eocene, there is no evidence preserved that unequivocally supports a position there. The Jurassic Acanthostrophia acanthica from Italy seems to be the oldest known record of Abyssochrysidae, and the most reliable occurrence of the family, older than from the Miocene. Other fossil, pre‐Miocene species that have been classified in the Abyssochryssidae are provisionally referred to Hokkaidoconchidae. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154 , 421–436.     

FOSSIL FLORAL EVIDENCE OF MALPIGHIACEAE AND AN EARLY PLANT-POLLINATOR RELATIONSHIP

Fossil flowers with affinities to Malpighiaceae have been discovered in the Middle Eocene Claiborne formation of northwestern Tennessee. The new taxon Eoglandulosa warmanensis gen. et sp. nov. Taylor and Crepet, has paired glands on the five sepals, clawed petals and tricolporate pollen with reticulate ornamentation and an unusual infratectal wall structure of anastomosing elements. The fossil is similar in wall structure to some extant species of Malpighiaceae. Glandular floral morphology in extant species is associated with specific anthophorid bee pollinators and the fossil evidence suggests that such specific plant-pollinator relationships existed during the Eocene. This fossil species also suggests that by the Eocene, South American floral elements had migrated to North America via island pathways, and that the Mississippi embayment was nearly frost-free.     

A New Small-Bodied Species of <Emphasis Type="Italic">Palaeonictis</Emphasis> (Creodonta,Oxyaenidae) from the Paleocene-Eocene Thermal Maximum

Oxyaenid creodonts are extinct carnivorous mammals known from the Paleogene of North America, Europe, and Asia. The genus Palaeonictis is represented by three species that together span the late Paleocene to early Eocene of North America, and at least one species from the early Eocene of Europe. Previously, only a single trigonid of Palaeonictis was known from the interval encompassing the Paleocene-Eocene Thermal Maximum (PETM) in North America. We describe Palaeonictis wingi sp. nov. from the PETM in the Cabin Fork drainage, southeastern Bighorn Basin, Wyoming, based on associated right and left dentaries with P₂-M₂. Palaeonictis wingi sp. nov. is substantially smaller than the other North American congeners, making it similar in size to P. gigantea from the earliest Eocene of Europe and the previously described PETM specimen. We suggest that a form similar to the large-bodied late Paleocene P. peloria from North America gave rise to two smaller species in the earliest Eocene of North America (P. wingi) and Europe (P. gigantea). Palaeonictis wingi may have given rise to P. occidentalis following the PETM in North America. Dispersal of Palaeonictis to Europe coincided with rapid global warming of 5–10°C and related geographic range shifts in plants and other animals during the PETM. It has been suggested that certain mammalian lineages decreased in body size during the PETM, possibly in response to elevated temperature and/or higher CO₂ levels. Results from a dietary analysis of Palaeonictis indicate that it was an omnivore that primarily consumed meat. This suggests that the decreased nutritious quality of vegetation caused by increased CO₂ levels was not the direct contributing factor that caused body size reduction of this lineage during the PETM. Other selective pressures such as temperature, aridity, and prey size may have also contributed to the smaller body size of carnivorous mammals during this interval, although the presence of smaller species could also be explained by latitudinal range shifts of mammals during the PETM.     

A new genus and species of triggerfish from the Middle Eocene of the Northern Caucasus,the earliest member of the Balistidae (Tetraodontiformes)

Until now, the earliest known members of the triggerfish family Balistidae have been two genera from the Oligocene. Herein is described the new balistid Gornylistes prodigiosus gen. et sp. nov. from the uppermost Middle Eocene (Kuma Horizon) of the Northern Caucasus (Gorny Luch locality); it is as thoroughly modern in its bauplan as the taxa of balistids from the Oligocene and more recent periods, and far more advanced morphologically than the several stem taxa of the balistoid + ostracioid clade known from earlier in the Middle and Lower Eocene and from the Upper Paleocene.     

Evolution of Paleocene to Early Eocene larger benthic foraminifer assemblages of the Indus Basin,Pakistan

Afzal, J., Williams, M., Leng, M.J., Aldridge, R.J. & Stephenson, M.H. 2011: Evolution of Paleocene to Early Eocene larger benthic foraminifer assemblages of the Indus Basin, Pakistan. Lethaia, Vol. 44, pp. 299–320. The Paleocene–Early Eocene carbonate successions of the Indus Basin in Pakistan formed on the northwestern continental shelf margin of the Indian Plate in the eastern Tethys Ocean. Based on larger benthic foraminifera (LBF), eight Tethyan foraminiferal biozones (SBZ1–SBZ8) spanning the Paleocene to Early Eocene interval are identified. The base of the Eocene is identified by the first appearance of Alveolina sp. Other stratigraphically important LBFs that are characteristic of the earliest Eocene are Ranikothalia nuttalli, Discocyclina dispansa and Assilina dandotica. Stable isotope analysis through the Paleocene–Eocene (P–E) boundary interval identifies more positive δ¹³C values for the Late Paleocene (+3.4‰ to +3.0‰) and lower values (+2.7‰ to +1.6‰) for the earliest Eocene. However, there is insufficient sampling resolution to identify the maximum negative δ¹³C excursion of the Paleocene–Eocene Thermal Maximum. During Late Paleocene times LBF assemblages in the Indus Basin were taxonomically close to those of west Tethys, facilitating biostratigraphic correlation. However, this faunal continuity is lost at the P–E boundary and the earliest Eocene succession lacks typical west Tethys Nummulites, while Alveolina are rare; LBFs such as Miscellanea and Ranikothalia continue to dominate in the Indus Basin. The absence of Nummulites from the earliest Eocene of Pakistan and rarity of Alveolina, elsewhere used as the prime marker for the base of the Eocene, may imply biogeographical barriers between east and west Tethys, perhaps caused by the initial stages of India‐Asia collision. Later, at the level of the Eocene SBZ8 Biozone, faunal links were re‐established and many foraminifera with west Tethys affinities appeared in east Tethys, suggesting the barriers to migration ceased. □Biostratigraphy, Eocene, India‐Asia collision, larger benthic foraminifera, palaeoecology, Paleocene.