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Middle Miocene carnivorans from the Monarch Mill Formation, Nevada

100%

Smith K., Czaplewski N., Cifelli R. L.

Acta Palaeontologica Polonica

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2016

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tom 61

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nr 1

The lowest part of the Monarch Mill Formation in the Middlegate basin, west-central Nevada, has yielded a middle Miocene (Barstovian Land Mammal Age) vertebrate assemblage, the Eastgate local fauna. Paleobotanical evidence from nearby, nearly contemporaneous fossil leaf assemblages indicates that the Middle Miocene vegetation in the area was mixed coniferous and hardwood forest and chaparral-sclerophyllous shrubland, and suggests that the area had been uplifted to 2700–2800 m paleoaltitude before dropping later to near its present elevation of 1600 m. Thus, the local fauna provides a rare glimpse at a medium- to high-altitude vertebrate community in the intermountain western interior of North America. The local fauna includes the remains of fish, amphibians, reptiles, birds, and 25 families of mammals. Carnivorans, the focus of this study, include six taxa (three of which are new) belonging to four families. Canidae are represented by the borophagine Tomarctus brevirostris and the canine Leptocyon sp. indet. The earliest record and second North American occurrence of the simocyonine ailurid Actiocyon is represented by A. parverratis sp. nov. Two new mustelids, Brevimalictis chikasha gen. et sp. nov. and Negodiaetictis rugatrulleum gen. et sp. nov., may represent Galictinae but are of uncertain subfamilial and tribal affinity. The fourth family is represented by the felid Pseudaelurus sp. indet. Tomarctus brevirostris is limited biochronologically to the Barstovian land mammal age and thus is consistent with the age indicated by other members of the Eastgate local fauna as well as by indirect tephrochronological dates previously associated with the Monarch Mill Formation. Actiocyon parverratis sp. nov. extends the temporal range of the genus Actiocyon from late Clarendonian back to the Barstovian. The Eastgate local fauna improves our understanding of mammalian successions and evolution, during and subsequent to the Mid-Miocene Climatic Optimum (~14–17 Ma).

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Ailurid carnivoran mammal Simocyon from the late Miocene of Spain and the systematics of the genus

80%

Peigne S., Salesa M. J., Anton M., Morales J.

Acta Palaeontologica Polonica

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2005

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tom 50

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nr 2

We describe the most complete and best−preserved materials assigned to Simocyon from Spain. Specimens come from the late Miocene (Vallesian) locality of Batallones−1, Province of Madrid and are assigned to Simocyon batalleri. Cranial, mandibular and dental anatomy of S. batalleri from Batallones−1 is described and compared with those of known species of Simocyon. We review the systematic status and the definition of the species of Simocyon and we analyse the morphological variation within Simocyon. Three species are recognized as valid. S. batalleri is known from several Vallesian localities (mainly MN 10) of Spain. S. diaphorus, from the early Vallesian of Germany (Mammal Zone MN 9), is the geologically oldest European species. The type species S. primigenius is Turolian in age and known from several localities of Europe, North America, and China. The species includes the junior synonyms S. zdanskyi and S. marshi. The status of Simocyon hungaricus is not resolved. Simocyon simpsoni is excluded here from Simocyon and reassigned to its original generic name Protursus. On the basis of the material described here, we propose a differential diagnosis for Simocyon batalleri. This species is morphologically intermediate between the more primitive S. diaphorus, which has a less reduced p3; and the more derived S. primigenius, characterized by a modified mandible (e.g., more vertical and more expanded coronoid process, longer angular process). The evolution of the genus Simocyon is characterized by a trend toward a more crushing adaptation involving at least a modification of the posterior part of the mandible. A reconstruction of the skull and life appearance of Simocyon is proposed.

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An arctomorph carnivoran skull from the Phosphorites du Quercy and the origin of procyonids

61%

Wolsan M., Lange-Badre B.

Acta Palaeontologica Polonica

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1996

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tom 41

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nr 3

277-298

The size and morphological characteristics of a skull of an arctomorph carnivoran mammal from Mouillac (old collection of the Phosphorites du Quercy, of unknown age) in France closely match those of the holotype of the earliest known procyonid Pseudobassaris riggsi and another skull referred to this species, both from old collections of the Phosphorites du Quercy (Caylus and Mouillac), probably earliest Late Oligocene in age. The skull is more primitive in morphology than those of Pseudobassaris riggsi and every other known procyonid, approaching a hypothetical primitive procyonid morphotype. The only, but methodologically fundamental, departure from this morphotype is the lack of the procyonid suprameatal fossa, which is the crucial synapomorphy of the family Procyonidae. To explain the phylogenetic and taxonomic status of the arctomorph represented by the skull, three competing hypotheses are put forward. Hypothesis A, which considers the arctomorph as an individual of Pseudobassaris riggsi, assumes that the procyonid suprameatal fossa first appeared in a common ancestor of Pseudobassaris and other procyonids but was still of variable occurence within Pseudobassaris riggsi. Hypothesis B, which proposes the arctomorph as a member of a new Pseudobassaris species ancestral to Pseudobassaris riggsi, concludes that the procyonid suprameatal fossa arose in Pseudobassaris riggsi and in the Procyonidae independently, excluding Pseudobassaris from the procyonids. Hypothesis C, which recognizes the arctomorph as a representative of a new species of a new genus of the paraphyletic procyonid stem group, presumes that the procyonid suprameatal fossa originated in a common ancestor of Pseudobassaris and other procyonids after the new genus had become detached from the ancestral stock of the Procyonidae.

Ograniczanie wyników

3 Acta Palaeontologica Polonica

1 Anton M.

1 Cifelli R. L.

1 Czaplewski N.

1 Lange-Badre B.

1 Morales J.

1 Peigne S.

1 Salesa M. J.

1 Smith K.

1 Wolsan M.

1 2016

1 2005

1 1996

Middle Miocene carnivorans from the Monarch Mill Formation, Nevada

Ailurid carnivoran mammal Simocyon from the late Miocene of Spain and the systematics of the genus

An arctomorph carnivoran skull from the Phosphorites du Quercy and the origin of procyonids