The most ancient caviine rodent (Hystricognathi,Cavioidea) comes from the late Miocene of Northwest Argentina (South America)

The family Caviidae is one of the most diverse groups among South American hystricognath rodents and is represented by three main living lineages: Caviinae (cavies), Dolichotinae (maras) and Hydrochoerinae (capybaras). Caviinae includes the smaller forms of caviids represented by the extant Microcavia, Cavia and Galea. They are distributed in a wide range of environments throughout South America. In addition, three other genera from the late Miocene–Pliocene (Dolicavia, Palaeocavia and Neocavia) are recognised in high latitudes. In northwestern Argentina, the fossil forms of Caviinae have been poorly studied and for most of them there is no precise stratigraphic information. We describe and evaluate the phylogenetic affinities of the most ancient caviine from the Chiquimil Formation, Catamarca province, northwestern Argentina (9.14–7.14 ma). According to the morphological analysis of the mandibular and dental morphology and the results of the phylogenetic analysis, we assigned the new species tentatively to genus Palaeocavia. The phylogenetic position of the new species suggests an earlier origin for the lineage Palaeocavia + Cavia and for the entire clade Caviinae.     

Biology of the solitary wasp Trypoxylon (Trypargilum) agamemnon Richards 1934 (Hymenoptera: Crabronidae) in trap‐nests

Buschini, M.L.T. and Fajardo, S. 2009. Biology of the solitary wasp Trypoxylon (Trypargilum) agamemnon Richards 1934 (Hymenoptera: Crabronidae) in trap‐nests. —Acta Zoologica (Stockholm) 91 : 426–432. Some Trypoxylon species build their nests in preexisting tubular cavities like hollow stems and beetle borings in branches. Study of the biology of these insects is relatively easy because the females of these wasps nest with enormous success in trap‐nests. The aim of this study was to investigate the abundance, seasonality and life‐history of Trypoxylon agamemnon. For capture of these insects, trap‐nests were installed in the Parque Municipal das Araucárias in araucaria forest, grassland and swamp, from December, 2001 to December, 2005. Two hundred and ninety seven nests were obtained. They were constructed more often during the summer (from December to April). The nests were built only in araucaria forest and consisted of a linear series of cells, divided by mud partitions, whose number varied from 1 to 7. Normally they have only one vestibular cell. The inner cells had been provisioned, usually with spiders of Anyphaenidae family. Sex‐ratio was strongly female biased. Its main natural enemies included Chrysididae, Ichneumonidae and Tachinidae.     

A brittle star bed from the Miocene of Patagonia, Argentina

Martínez, S., del Río, C.J. & Pérez, D.E. 2010: A brittle star bed from the Miocene of Patagonia, Argentina. Lethaia , Vol. 43, pp. 1–9.
As a consequence of the extremely poor fossil record of brittle stars, every new discovery is important. The Miocene example studied herein involves the recently described species Ophiocrossota kollenbergorum Caviglia, Martínez & del Río recovered from the Chenque Formation of southeastern Argentina. The information used here is derived from unpublished data and a new record from two discrete, thin, monospecific patches. The main taphonomic features of the patches, namely the presence of specimens concordant with bedding planes, (with either aboral or oral side upwards), and the good preservation of the delicate discs (ca. 6 mm wide on average), and the preservation of un-oriented arms complete with fragile tips (not wider than 0.2 mm), point to a suddenly buried census assemblage. Although broken or isolated arms were found, this is attributed to the erosive environmental conditions of the abrasion platform where the studied exposure is located today. Size frequency distributions suggest that both patches were buried at different seasons. Observed densities are 77 and 143 individuals/m², and distances between individuals are random. The arm length/disc diameter ratio indicates that Ophiocrossota kollenbergorum may have been an epifaunal surface dweller. No signs of predation (such as regenerated arms), were identified.     

Systematic position of the Mesotheriidae (Notoungulata) from the Mariño Formation (Miocene) in Divisadero Largo, Mendoza, Argentina

This paper deals with the detailed taxonomic study of the first mammal remains from the Mariño Formation in the Divisadero Largo area, Mendoza, central west Argentina. This area was well-known by the fossils recovered from the Triassic levels and particularly by the faunal assemblage from the Cenozoic levels corresponding to the Divisadero Largo Formation. Until recently, no mammal remains had been accurately reported for the Mariño Formation, Miocene in age. The specimen consists in an almost complete upper jugal series (teeth found separated from the maxillary bone except the M3) of a small Mesotheriidae (Notoungulata), which was preliminary identified as Mesotheriinae indet. The main characteristic of these teeth is their small size, significatively lesser than that of the Miocene genera Eutypotherium, Typotheriopsis and Pseudotypotherium, being closer to Mycrotypotherium from Bolivia and the Chilean species from the Chucal Formation. The direct comparison with these latter forms has allowed a more detailed study and the recognition of the material here described as cf. Altitypotherium chucalensis, with all cautions inherent to the incompleteness of the material.     

Tropical freshwater teleosts from Miocene beds of eastern Patagonia, southern Argentina

Loricariid and pimelodid-like siluriforms—along with undetermined percomorph—are described for the first time from Patagonia. Vertebrate fossils, including fish, mammals and birds, were found in beds attributed to the top of the Puerto Madryn Formation. These levels supposedly corresponded to the “Rionegrense marino” of former authors. Mammals occurring in the site suggest a Huayquerian age for the fossiliferous beds. The base of the Huayquerian was dated at about 9 Ma and the top is younger than 6.5 Ma. Radioisotopic dating in the marine shell beds of the Puerto Madryn Formation ranges from 11 to 9 Ma. Consequently, the section described here appears to be younger than the typical Puerto Madryn Formation from which it is separated by an unconformity. The section is correlated with the type Río Negro Formation from northern Patagonia, which also includes Huayquerian fossils. Freshwater fishes were previously unknown in beds younger than the middle Miocene in southern South America. This is also the southernmost record of loricariid fishes. The association of aquatic continental and terrestrial vertebrates indicates for the first time in Península Valdés beds of freshwater origin. The evidence apported by fossils is also in agreement with global climate trends. The local extinction of loricariids in Patagonia possibly occurred much later than the time of deposition.     

Reappraisal of the giant caviomorph rodent Phoberomys burmeisteri (Ameghino, 1886) from the late Miocene of northeastern Argentina,and the phylogeny and diversity of Neoepiblemidae

Phoberomys is a giant caviomorph rodent included in the extinct Neoepiblemidae. It is recorded in the late Miocene-Pliocene of South America (Argentina, Venezuela, Brazil and Peru), and is one of the largest rodents that have ever lived. In this contribution we study specimens of Phoberomys from the ‘Mesopotamiense’, late Miocene of Entre Ríos Province (Argentina), including several unpublished specimens and the holotypes of the five nominal species (Ph. burmeisteri, Ph. praecursor, Ph. insolita, Ph. lozanoi and Ph. minima) previously recognised for this unit. Our study indicates that all Mesopotamian specimens belong to Phoberomys burmeisteri, and that the differences among them reveal individual and ontogenetic variation. Our phylogenetic analysis indicates that Neoepiblemidae is monophyletic and includes Phoberomys, Neoepiblema, and Perimys. Phoberomys species are recovered as a clade, which is more closely related to Neoepiblema than to the Patagonian Perimys. In addition, our study shows that Eusigmomys is not a Neoepiblemidae, but a Dinomyidae.     

Hypsosteiromys (Rodentia, Hystricognathi) from the Early Miocene of Patagonia (Argentina), the only Erethizontidae with a tendency to hypsodonty

Hypsosteiromys is the only New World porcupine that shows a tendency to hypsodonty. It is recorded exclusively from the Colhuehuapian Age (Early Miocene) of central Patagonia (Argentina). In addition to the type species, a second one, Hypsosteiromys nectus(AMEGHINO, 1902), is recognized, from the southern cliff of Colhuehuapi Lake (Chubut province). It differs from the type species in the lesser development of the anterolabial and posteroflexid notches of the m1-3, shorter p4 and dp4, and more slender incisors. Dental morphology suggests that the species of Hypsosteiromys lived in more open areas than most fossil and living Erethizontidae.     

Late Miocene continental biota in Northeastern Patagonia (Península Valdés, Chubut, Argentina)

A new vertebrate faunal assemblage was recently discovered from the uppermost part of the late Miocene Puerto Madryn Formation. These deposits crop out along the southwestern coast of the Península Valdés area near Punta Delgada (Chubut Province, Argentina). The exhumed vertebrate fauna includes a range of fish, bird and mammal taxa, of which the latter are most varied and abundant. The new findings represent the first record of continental fossil vertebrates in the Puerto Madryn Formation and this is the first assemblage of late Miocene continental vertebrates recorded to the south of Río Negro Province. It also includes the southernmost record of Hydrochoeridae rodents, Dendrocygninae birds and Loricariidae fishes. The mammals suggest that the fossil-bearing sediments are Huayquerian in age. The climate during the accumulation of late Miocene deposits in this region is inferred to have been warmer and seasonally drier than that of today.     

A new species of Gaimanophis (Serpentes,Boidae) from the Miocene of northwestern Argentina with remarks on the Neogene boids of South America

Gaimanophis is an extinct boid genus represented so far by a single species (Gaimanophis tenuis) known by isolated vertebrae from the early Miocene of Patagonia. In this paper, a new species of Gaimanophis is described from the India Muerta Formation (late Miocene) of Tucumán province (Argentina). Gaimanophis powelli sp. nov. distinguishes itself from G. tenuis mainly in its larger size, prezygapophyses less slanting, neural spine shorter dorsally than ventrally, and zygosphene straight bearing an anteriorly protruding tongue. This record indicates a wider temporal and geographical distribution of the genus from the early Miocene of Patagonia to the late Miocene of northwestern Argentina. The recognition of a new species of boid in South America increases the known diversity of this group. Although boids have inhabited in this territory since the Paleocene, fossils belonging to the group only show a glimpse of the real past diversity in the continent.     

Leftover prey remains: a new taphonomic mode from the Late Miocene Cerro Azul Formation of Central Argentina

The Cerro Azul Formation (La Pampa Province, Argentina) comprises a rich vertebrate fauna of small mammals dominated by notoungulates and rodents. The fauna pertains to the Late Miocene specifically to the Huayquerian Stage/Age. Taphonomic analysis of micro‐mammals from Estancia Ré locality evidenced that the faunal assemblage was accumulated by the activity of a predator. This assemblage was compared with others from the Cerro Azul Formation in Telén and Caleufú localities (La Pampa Province), previously interpreted as products of predator activities. These microfossil accumulations differ from assemblages attributed to pellets and faeces produced by modern predators (nocturnal and diurnal bird raptors and carnivore mammals). However, due to their anatomical representation, degree of bone breakage and presence of tooth marks, they are interpreted as accumulations of uneaten prey remains discarded by the predator. The predator involved could not be determined with certainty, although the presence of tooth marks in some skeletal remains and the presence of coprolites in Telén and Caleufú suggest that it could be a carnivore mammal. Similarities in the accumulation mechanism, patterns of preservation and sedimentary contexts in the three assemblages support the recognition of a new taphonomic mode, termed ‘leftover prey remains’.     

New Late Miocene murids from China (Mammalia, Rodentia)

New murids of Late Miocene (medial Baodean Chinese Mammal Unit) age from Inner Mongolia, northern China, and from Yunnan Province, southern China, are described. Hansdebruijnia perpusilla nov. sp. represents the earliest known and morphologically most primitive species of the genus, which is known from the latest Miocene of Europe and western Asia. The new species suggests an eastern Palaearctic origin of Hansdebruijnia. “Progonomys” yunnanensisQIU and STORCH, 1990 from Lufeng, Yunnan Province, is referred to Linomys nov. gen. New samples from Leilao, Yuanmou County, Yunnan Province, are included in this species, although this population is somewhat more primitive than that from Lufeng. Leilaomys zhudingi nov. gen. and sp. from Leilao shows a unique combination of apomorphic and plesiomorphic characters, which suggest an early divergence from the murid stem. The new findings indicate that our knowledge of the early radiation of murids in southeast Asia is still in its infancy.     

Paleosols and paleoenvironments of the middle Miocene,Maboko Formation,Kenya

The middle Miocene (15 Ma) Maboko Formation of Maboko Island and Majiwa Bluffs, southwestern Kenya, has yielded abundant fossils of the earliest known cercopithecoid monkey (Victoriapithecus macinnesi), and of a kenyapithecine hominoid (Kenyapithecus africanus), as well as rare proconsuline (Simiolus leakeyorum, cf. Limnopithecus evansi) and oreopithecine apes (Mabokopithecus clarki, M. pickfordi), and galagids (Komba winamensis). Specific habitat preferences can be interpreted from large collections of primate fossils in different kinds of paleosols (pedotypes). Fossiliferous drab-colored paleosols with iron-manganese nodules (Yom pedotype) are like modern soils of seasonally waterlogged depressions (dambo). Their crumb structure and abundant fine root-traces, as well as scattered large calcareous rhizoconcretions indicate former vegetation of seasonally wet, wooded grassland. Other fossiliferous paleosols are evidence of nyika bushland (Ratong), and early-successional riparian woodland (Dhero). No fossils were found in Mogo paleosols interpreted as saline scrub soils. Very shallow calcic horizons (in Yom, Ratong, and Mogo paleosols) and Na-montmorillonite (in Mogo) are evidence of dry paleoclimate (300-500 mm MAP=mean annual precipitation). This is the driest paleoclimate and most open vegetation yet inferred as a habitat for any Kenyan Miocene apes or monkeys. Victoriapithecus was abundant in dambo wooded grassland (Yom) and riparian woodland (Dhero), a distribution like that of modern vervet monkeys. Kenyapithecus ranged through all these paleosols, but was the most common primate in nyika bushland paleosols (Ratong), comparable to baboons and macaques today. Mabokopithecus was virtually restricted to riparian woodland paleosols (Dhero), and Simiolus had a similar, but marginally wider, distribution. Habitat preferences of Mabokopithecus and Simiolus were like those of modern colobus monkeys and mangabeys. A single specimen of Komba was found in dambo wooded grassland paleosol (Yom), a habitat more like that of the living Senegal bushbaby than of rainforest galagids. A shift to non-forest habitats may explain the terrestrial adaptations of Victoriapithecus, basal to the cercopithecid radiation, and of Kenyapithecus, basal to the hominoid radiation. Both taxa are distinct from earlier Miocene arboreal proconsulines, oreopithecines and galagids.     

Dental evolution in Neophanomys (Rodentia, Octodontidae) from the late Miocene of central Argentina

The evolutionary pattern of the molar morphology of the small caviomorph (Octodontidae) Neophanomys from the late Miocene Cerro Azul Formation of central Argentina is analyzed. Two new species (chronomorphs) are recognized, which constitute an anagenetically evolving lineage with a gradual and directional pattern of increasing molar hypsodonty. Dental changes related to increasing hypsodonty are comparable to those of the octodontid lineage Chasichimys also recovered from the Cerro Azul Formation. However, Neophanomys shows comparatively less variation in gross morphology and there are no evidences that this lineage achieved euhypsodonty. In contrast, important changes in enamel microstructure (schmelzmuster) are observed among different populations of Neophanomys, supporting the hypothesis that these changes can occur at least partially independently from modifications in dental gross morphology. The patterns of dental evolution detected in the Neophanomys and Chasichimys-Xenodontomys lineages and the unequivocal polarity of the changes involved, related to increasing hypsodonty, reinforce the hypothesis that chronological differences exist among late Miocene outcroppings of Cerro Azul Formation in central Argentina.     

New and interesting desmids (Zygnematales, Chlorophyceae) collected from Brazil and Argentina

The morphology and taxonomy of nine desmid taxa belonging to the three genera Closterium, Euastrum and Cosmarium are studied based on freshwater algal collections from Brazil and Argentina. They represent five new varieties (Closterium cynthia De Notaris var. minutum Kanetsuna var. nov., Euastrum attenuatum Wolle var. saitoi Kanetsuna var. nov., Cosmarium laticollum Delponte var. minutum Kanetsuna var. nov., Cosmarium pseudovariolatum Grönblad var. major Kanetsuna var. nov. and Cosmarium taxichondrum Lundell var. yamagishii Kanetsuna var. nov.), two new forms (Euastrum hypochondrum Nordstedt var. hypochondrum f. divergens Kanetsuna f. nov. and Euastrum insulare (Wittrock) Roy var. silesiacum (Gronblad) Krieger f. brasiliense Kanetsuna f. nov.) and one new status (Cosmarium pseudovariolatum Gronblad var. incrassatum (Scott et Gronblad) Kanetsuna f. elonga‐tum (Scott et Gronblad) Kanetsuna stat. nov.). In addition, a new combination (Cosmarium pseudovariolatum Gronblad var. incrassatum (Scott et Gronblad) Kanetsuna comb, nov.) is proposed.     

Milk molars or extra premolars in Mesotheriinae (Mesotheriidae,Notoungulata): New insights into an old controversy

A recently recovered specimen of Mesotheriinae (Mesotheriidae, Notoungulata) from the late Miocene-early Pliocene of La Rioja Province (Argentina), CRILAR Pv 433, corresponds to an individual with three upper premolars, which appears to be an “anomaly” among mesotheriines. The detailed study of this specimen, however, brings up an old controversy on the interpretation of different mesotheriine specimens with three upper or two lower premolars. After being described as different taxa, these were later considered to be juvenile representatives of other known species. The three upper or two lower teeth were interpreted as the milk molars DP2–4 and dp3–4, respectively, which would be replaced in adult life by two upper (P3–4) and one lower (p4) permanent premolars. The new material leads us to set up a different interpretation. In our opinion, all these specimens actually preserve the permanent dentition, corresponding to different ontogenetic stages of more or less young individuals. This consideration implies the necessity of a deep systematic revision of the whole subfamily, keeping in mind this new point of view and the ontogenetic variation within a species. Therefore, the presence of P2/p3 is not enough to define a different taxon at this moment. Pending this taxonomic revision, the dental morphology of CRILAR Pv 433 resembles both Typotheriopsis (e.g., upper premolars with one labial sulcus) and Pseudotypotherium (e.g., P4 with lingual groove, wide median lobe of M3) as these two late Miocene genera are currently characterized. Furthermore, P2/p3 could be expelled soon in the lifetime of individuals, and even the presence of P2/p3 could be a variable character within the same taxon; if so, this might reflect an evolutionary trend to the loss of a dental element within mesotheriines, but the revision of a large sample is necessary to support or reject these hypotheses.     

Carnivores from the early/middle Miocene locality of Antonios (Chalkidiki, Macedonia, Greece)

The mammal locality of Antonios is one of the few known early-middle Miocene ones of Greece with large mammals. It is situated in Chalkidiki Peninsula (Macedonia, Greece) and includes both small and large mammals. The study of the carnivores found in Antonios indicates the presence of the following taxa: Proputorius cf. P. sansaniensis, Protictitherium gaillardi, Protictitherium cf. P. crassum, Percrocuta sp., Percrocutidae indet. and Pseusaelurus romieviensis. The material of each taxon is described, compared with other material from various Eurasian localities and determined. The species P. cf. sansaniensis and P. romieviensis are traced for first time in Eastern Mediterranean, while Percrocuta for first time in Greece. The presence of the other carnivoran taxa in the Antonios fauna is also interesting as they are recognized in older stratigraphic levels enriching our knowledge about their stratigraphic distribution. The carnivores of Antonios cannot offer significant data for the dating of the fauna but its age is discussed using the data coming from the carnivores as well as those from older studies of the micromammals and suoids.     

An assessment of the diversity of early Miocene Scolopaci (Aves,Charadriiformes) from Saint‐Gérand‐le‐Puy (Allier,France)

Abstract: ‘Totanus’lartetianus, Elorius paludicola and ‘Tringa’gracilis are the three scolopacid birds from the early Miocene of Saint‐Gérand‐le‐Puy described by the French palaeontologist Milne‐Edwards in the 19th century. Since then, no revision of these taxa has been performed. Our re‐examination revealed that not much of the material originally assigned to ‘Totanus’lartetianus can be retained within the species. Presumably plesiomorphic features of the humerus – and potentially the coracoid we attributed to this taxon – indicate that it is misplaced in the extant scolopacid genus and may not even belong to the Scolopacidae (sandpipers and allies), and we therefore place it in the new genus Scolopacimilis. Comparisons of the material assigned to Elorius paludicola and ‘Tringa’gracilis show that they are morphologically similar, both exhibiting distinct scolopacid anatomical features. The latter, however, cannot be referred to the extant taxon Tringa and is classified into the new genus Parvelorius. We further introduce three new species, ?Elorius limosoides sp. nov., and ?Parvelorius calidris sp. nov., which we have tentatively assigned to the extinct scolopacid genera Elorius and Parvelorius, respectively, and Becassius charadriioides gen. et. sp. nov., which, together with Scolopacimilis, display a morphology uncharacteristic for extant Scolopaci. For the first time we have assigned skulls to some of the postcranial elements described in this study. The presence of at least six species of Scolopaci from the early Miocene considerably increases the number of members of the group known from this time.