Miocene Forms Research Articles

Aragonictis araid, gen. et sp. nov., a small-sized hypercarnivore (Carnivora, Mustelidae) from the upper middle Miocene of the Iberian Peninsula (Spain)

ABSTRACT Small to medium-sized mustelids from the last 18 million years represent a heterogeneous group of carnivorans with a wide-ranging record in the northern hemisphere. They were first referred to the genera Mustela and Martes, but lately ascribed to the latter, and hence considered as the longest-lived genus within Mustelidae. However, a great many of these forms have been based upon fragmentary material and Martes has conformed progressively to a wastebasket nomen for species of uncertain relationships. Here, we describe dentognathic material of a small-sized mustelid from three middle Miocene (MN7 + 8, latest Aragonian) localities of the Iberian Peninsula that constitutes a new genus and species. Aragonictis araid, gen. et sp. nov. represents a distinct taxon if compared with early/middle Miocene forms ascribed to “Martes” spp., especially the similar-sized early Miocene Circamustela? laevidens and the middle Miocene “Martes” caedoti and “Martes” delphinensis. The finding of particular features in A. araid (low p2–3, loss or reduction of the p4 accessory cuspid with its main cuspid centrally located, presence of a sharp, beveled and lingually open m1 talonid, and reduction of M1 lingual platform) indicates affinities with the late Miocene Circamustela in the range of hypercarnivory. Our reassessment of “Martes” indicates possible evidence of cladogenesis for Miocene mustelidae with, at least, two different events being recognized in Europe—the latter during MN7 + 8 to MN9 with presence of Aragonictis and Circamustela. The finding of A. araid further confirms the presence of more densely forested environments than expected in inner Iberia during the latest middle Miocene.

A review of Semigenetta (Viverridae, Carnivora) from the Miocene of Eurasia based on material from the hominid locality of Hammerschmiede (Germany)

The present article offers a detailed review of the taxonomy, distribution and palaeoecology of the genus Semigenetta. The study is based on new craniodental and postcranial remains of the genus from the early late Miocene (Tortonian) locality of Hammerschmiede (Bavaria, Germany). Most of the new specimens are attributed to the medium-sized species Semigenetta sansaniensis, whereas one lower carnassial is assigned to the large-sized Semigenetta grandis, making Hammerschmiede 4 the first known locality with two species of the genus. The variability of the material of S. sansaniensis from Europe allows us to revise the taxonomic weight of some previously used characters, and to identify the smaller-sized late Miocene form Semigenetta ripolli as a junior synonym of the former. Such an evolutionary transition of S. sansaniensis towards smaller forms is explained by niche partitioning with larger carnivorans of similar ecology, such as the herein reported S. grandis. Additionally, the species Semigenetta huaiheensis is here considered as a junior synonym of Semigenetta elegans.

A new pygmy armadillo (Cingulata, Euphractinae) from the late Miocene of Andean Argentina reveals an unexpected evolutionary history of the singular Prozaedyus lineage

The extinct euphractine Prozaedyus was recognized remarking the evident morphological resemblance of the dorsal carapace with the extant piche or pygmy armadillo Zaedyus pichiy. From a phylogenetic viewpoint, Prozaedyus has been interpreted as an early diverging Euphractinae restricted, at the moment, to the late Oligocene and early mid Miocene levels (Deseadan to Laventan SALMAs) of southern South America (Argentina, Chile, and Bolivia). We report here a specimen (MSJ-317) coming from the late Miocene (Loma de Las Tapias Formation; ~9 Ma, Chasicoan Stage/Age) of western Argentina (San Juan Province), which represents a new species of Prozaedyus. The specimen includes an almost complete skull with complete dental series, some articulated fragments of the dorsal carapace and several isolated fixed and mobile osteoderms. Absence of teeth in the premaxillae, ornamentation pattern of fixed osteoderms, and presence of small foramina in the posterior and lateral margins of both mobile and fixed osteoderms, are characters that allow its inclusion within the genus Prozaedyus. Differences with the other known species of this genus include smaller size (~35–40%), cranial characters (e.g. position of the infraorbital foramen, palatine suture, morphology of the occipital condyles), and ornamentation pattern of mobile osteoderms. The phylogenetic analysis carried out support its relation as a sister group of the other Prozaedyus species, revealing an ancient divergence for the new taxon, occurred before that of the late Oligocene-early mid Miocene forms, and a distant phylogenetic position from Zaedyus pichiy. This new finding represents the youngest record of the genus, extending its biochron several millions of years, and provides novel information on the poorly know post-Santacrucian forms. Additionally, the cranial anatomy of the new species suggests a carnivore/omnivore habit, similar to extant euphractine armadillos but contrary to the insectivore habit proposed for the other Prozaedyus species.

Middle Miocene Carnivora and Hyaenodonta from Fort Ternan, western Kenya

Fort Ternan is a middle Miocene (c. 13.7-13.8 Ma) site famous for its fossils of Kenyapithecus wickeri Leakey, 1962, considered the earliest African hominoid. Herein, the Carnivora and Hyaenodonta from this site are described and placed in their temporal context, showing the middle Miocene to be a time of transition from archaic carnivores of the early Miocene and carnivores of more modern aspect from the late Miocene. Fort Ternan includes: Amphicyonidae represented by ?Myacyon peignei n. sp., a new form distinguished by its hypercarnivorous m1, P4 with large protocone shelf, and M1 with reduced lingual shelf; Barbourofelidae, represented by a derived form; Percrocutidae, represented by abundant material of Percrocuta tobieni Crusafont & Aguirre, 1971; Viverridae, represented by the paradoxurines Kanuites lewisae Dehghani & Werdelin, 2008, and cf. Orangictis Morales & Pickford, 2005, and a putative viverrine; and Hyaenodonta represented by the teratodontine Dissopsalis pyroclasticus Savage, 1965 and a very large hyainailourine. This assemblage is a melange of forms harkening back to the early Miocene (the Hyaenodonta and Amphicyonidae), an evolving, still extant lineage (Viverridae), and more typical late Miocene forms (derived Barbourofelidae and Percrocutidae).

Barreleye Macropinna sp. (Argentiniformes, Opisthoproctidae) from the Miocene of Sakhalin Island, Russia

ABSTRACTThe first fossil spookfish (Argentiniformes: Opisthoproctidae) is described from deposits of the middle-upper Miocene Kurasi Formation of Sakhalin Island, Russia. The fossil is placed in the family Opisthoproctidae because of the posterior position of its dorsal fin, along with a very small mouth and very long pelvic fin. It is referred further to the genus Macropinna, based on the placement of the anterior margin of the anal fin under the posterior part of dorsal fin, and a close correspondence in vertebra and fin ray counts and body proportions with the only living species, Macropinna microstoma Chapman, 1939. The great similarity between fossil and Recent barreleyes suggests that this Miocene form is a representative of the Recent species or a stem member of M. microstoma.Citation for this article: Nazarkin, M. V. 2016. Barreleye Macropinna sp. (Argentiniformes, Opisthoproctidae) from the Miocene of Sakhalin Island, Russia. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1187158.

The new rare record of the late Oligocene lizards and amphisbaenians from Germany and its impact on our knowledge of the European terminal Palaeogene

There have been only a few studies on squamates from the late Oligocene of Europe, resulting in significant gaps in our knowledge of the reptile faunas from the latest Paleogene. Here, we report on new late Oligocene fossil material from two German localities, Herrlingen 11 (MP 28) and Herrlingen 9 (MP 29). The material can be assigned to the following major clades: Iguanidae, Gekkota, Lacertidae, Amphisbaenia, and Anguimorpha. The iguanid material shows that this clade was much more widely distributed in the Oligocene of Europe than previously thought, and also represents the youngest known record of this clade for Eurasia and Africa, with the exception of Madagascar. Although very fragmentary, the gekkotan material appears to be more similar to early Miocene forms such as Euleptes or Gerandogekko, rather than to early Oligocene taxa like Cadurcogekko, as indicated by the small size and morphology. The resemblance of the gekkotan fossils to Miocene forms suggests potential faunal turnover prior to the Paleogene–Neogene transition. The amphisbaenian material is represented by several types; the first can be allocated to Blanidae based on tooth count and the presence of a small 4th and an enlarged 3rd tooth, which is a derived feature. The second type is attributed to Palaeoblanus. Other cranial material is assigned to Amphisbaenia indet. The lacertid material consists of several amblyodont forms such as Dracaenosaurus, Pseudeumeces and Mediolacerta, as typically seen in other Oligocene deposits from Europe, but also includes non-ambylodont taxa such as Plesiolacerta and an undetermined lacertid. Especially common among the material are anguimorphs, which are here represented by Ophisaurus and a form that appears identical to the French Oligocene taxon described as coderetensis. Reinvestigation of the European Oligocene Dopasia (=Ophisaurus) shows that the taxa described as D. frayssensis and D. coderetensis are markedly different from the members of the clade Ophisaurus in the morphology of the posterior dentary region and that those taxa cannot be allocated to this genus. For this reason, we erected a new generic name: Ophisauromimus gen. nov. The composition of the Herrlingen fauna shows an interesting mix of ancient Paleogene and more modern Neogene faunal elements, while overall bearing many similarities to contemporaneous faunas from France.

Maroccosuchus zennaroi (Crocodylia: Tomistominae) from the Eocene of Morocco: phylogenetic and palaeobiogeographical implications of the basalmost tomistomine

Maroccosuchus zennaroi Jonet & Wouters, 1977 from the Ypresian of the Oulad Abdoun Basin (Morocco) is described in detail based on numerous and well-preserved specimens. A phylogenetic analysis including 64 ingroup taxa and 238 characters reveals that M. zennaroi is the basalmost tomistomine. This clade is supported by 10 unambiguous synapomorphies, while only two – both related to the snout shape and observed in gavialoids – support a closer relationship between Kentisuchus spenceri and later tomistomines. Their absence in M. zennaroi could reflect its intermediate morphology between basal crocodyloids and longirostrine tomistomines. This clearly indicates a Lower Eocene, and no older than Late Palaeocene age for the tomistomine emergence, questioning the Late Eocene, Oligocene and Miocene ages proposed for Gavialis–Tomistoma divergence by molecular analyses. Considering this analysis, the biogeographical history of the tomistomines is evaluated. This history begins in western Tethys during the Lower Eocene or latest Palaeocene, with M. zennaroi followed by several West European tomistomines. The Tethys becomes the centre of dispersal to North America, Africa and Asia. The phylogenetic analysis also suggests at least two independent dispersals from the Tethyan area to Asia, with the extant Tomistoma schlegelii more closely related to European Miocene forms in the first instance, and Toyotamaphimeya machikanense and Penghusuchus pani more closely related to the North American Thecachampsa in the second instance. However, the small number of remains from the Oligocene and Late Eocene does not allow a clear date of divergence and dispersal routes to be ascertained.

Bony outgrowths on the jaws of an extinct sperm whale support macroraptorial feeding in several stem physeteroids.

Several extinct sperm whales (stem Physeteroidea) were recently proposed to differ markedly in their feeding ecology from the suction-feeding modern sperm whales Kogia and Physeter. Based on cranial, mandibular, and dental morphology, these Miocene forms were tentatively identified as macroraptorial feeders, able to consume proportionally large prey using their massive teeth and robust jaws. However, until now, no corroborating evidence for the use of teeth during predation was available. We report on a new specimen of the stem physeteroid Acrophyseter, from the late middle to early late Miocene of Peru, displaying unusual bony outgrowths along some of the upper alveoli. Considering their position and outer shape, these are identified as buccal maxillary exostoses. More developed along posterior teeth and in tight contact with the high portion of the dental root outside the bony alveoli, the exostoses are hypothesized to have developed during powerful bites; they may have worked as buttresses, strengthening the teeth when facing intense occlusal forces. These buccal exostoses further support a raptorial feeding technique for Acrophyseter and, indirectly, for other extinct sperm whales with a similar oral apparatus (Brygmophyseter, Livyatan, Zygophyseter). With a wide size range, these Miocene stem physeteroids were major marine macropredators, occupying ecological niches nowadays mostly taken by killer whales.

Lorisine Primate from the Late Miocene of Kenya

The origin of African Lorisidae has been the subject of debate for the past half century, so far without resolution. The matter is complecated by the fact that strepsirrhines (Lorisiformes = Lorisidae + Galagidae) are rare in the African fossil record, with large gaps between occurrences in the Early Oligocene Fayum (Egypy) deposit, the Early Miocene strata of East Africa and the Plio-Pleistocene of the same region. Likewise, the Asian fossil record of this group is spotty, with only a few specimens described from the Late Miocene of Pakistan. In the search for evidence concerning the dichotomy between Lorisidae and Galagidae, authors have tended to focus on the Early Miocene fossils from Kenya and Uganda which is the only region to have yielded a reasonable diversity of forms. Unfortunately, the history of study has been marred by the description and interpretation of non-primate material as strepsirrhines (Lorisiformes spurii). This contrasts with the genuine strepsirrhine (Lorisiformes veri) fossil from the same region which have thrown much light on the group, but which have not yet resolved the issue of the timing or the modality of the dichotomy between the two families. At present, among the described African fossil lorisiformes only the genus Mioeuoticus is accepted by some, but not all, authors (Harrison, 2010) as a Lorisidae (or Lorisinae, all the others generally being classed as Galagidae (or Galginae) Walker (1987). It is thus of interest to put on record the discovery of a lorisid anout from the Late Miocene deposits of the Tugen Hills, Kenya, which is close in dimensions and some aspects of the Far East (Nycticebus, Nycticeboides) and West Africa (Arctocebus). The fossil does not particularly resemble any of the Early Miocene forms described from East Africa, and it is suggested that the lineage entered Africa during the Late Miocene at the same time that several other vertebrate groups spread into the continent from South-East Asia.

Lorisine Primate from the Late Miocene of Kenya

The origin of African Lorisidae has been the subject of debate for the past half century, so far without resolution. The matter is complecated by the fact that strepsirrhines (Lorisiformes = Lorisidae + Galagidae) are rare in the African fossil record, with large gaps between occurrences in the Early Oligocene Fayum (Egypy) deposit, the Early Miocene strata of East Africa and the Plio-Pleistocene of the same region. Likewise, the Asian fossil record of this group is spotty, with only a few specimens described from the Late Miocene of Pakistan. In the search for evidence concerning the dichotomy between Lorisidae and Galagidae, authors have tended to focus on the Early Miocene fossils from Kenya and Uganda which is the only region to have yielded a reasonable diversity of forms. Unfortunately, the history of study has been marred by the description and interpretation of non-primate material as strepsirrhines (Lorisiformes spurii). This contrasts with the genuine strepsirrhine (Lorisiformes veri) fossil from the same region which have thrown much light on the group, but which have not yet resolved the issue of the timing or the modality of the dichotomy between the two families. At present, among the described African fossil lorisiformes only the genus Mioeuoticus is accepted by some, but not all, authors (Harrison, 2010) as a Lorisidae (or Lorisinae, all the others generally being classed as Galagidae (or Galginae) Walker (1987). It is thus of interest to put on record the discovery of a lorisid anout from the Late Miocene deposits of the Tugen Hills, Kenya, which is close in dimensions and some aspects of the Far East (Nycticebus, Nycticeboides) and West Africa (Arctocebus). The fossil does not particularly resemble any of the Early Miocene forms described from East Africa, and it is suggested that the lineage entered Africa during the Late Miocene at the same time that several other vertebrate groups spread into the continent from South-East Asia.

Primates

Primates

NEW INSIGHTS INTO THE GEOLOGICAL EVOLUTION OF THE DURBAN BLUFF AND ADJACENT BLOOD REEF, SOUTH AFRICA

The narrow, oceanic current-swept shelf of the Durban Bluff is characterised by Pleistocene aeolianites deposited unconformably onto a Cretaceous sequence. Subsequent beachrocks were deposited on and erosional features cut into the aeolianites, tracking a series of palaeocoastlines that extend from the supratidal zone to the outer continental shelf and record sea level fluctuations from the Last Interglacial to the present. High-resolution boomer seismics reveal a detailed sequence stratigraphy for the late Cretaceous drift sequence (Early Santonian to Late Maastrichtian) followed by a likely Miocene/Pliocene sequence preserved on the shelf edge, the first record of these deposits from the Durban continental shelf. Seven seismic units are recognised (Units A to G), bounded by regional sequence boundaries, maximum flooding surfaces and wave ravinement surfaces. Mapping of the Bluff Ridge and adjoining Blood Reef by geophysical surveys and scuba diving enabled subdivision of the Quaternary deposits into three aeolianite units and 13 beachrock units. Calcareous nannoplankton preserved in the aeolianite units indicate a late Pleistocene to Holocene age (Zone NN21, maximally 290 ka) for the deposits and the presence of reworked Miocene forms provides further support for the existence of Neogene on the shelf edge. A new Infared Stimulated Luminescence age of 60 ka obtained from offshore aeolianite indicates dune-building during the Marine Isotope Stage 4 glacial period.

The Cricetidae (Rodentia, Mammalia) from the Ulantatal area (Inner Mongolia, China): New data concerning the evolution of Asian cricetids during the Oligocene

The Oligocene fossil deposits of Ulantatal in Inner Mongolia show an amazing faunal richness, comparable to the highly diversified contemporaneous faunas from the Valley of Lakes in Central Mongolia. To date, only a few taxa have been described. The present study consists of the description of 13 species of cricetid rodents from seven localities ranging in age from the late Early Oligocene to the Late Oligocene epoch. Most of them are new and belong to Eucricetodontinae, the dominating cricetid group at Ulantatal. These taxa give new information regarding the evolution of the Cricetidae in Central and Eastern Asia during the Oligocene. Four new species, Eucricetodon jilantaiensis nov. sp., Eucricetodon bagus nov. sp., Bagacricetodon tongi nov. gen., nov. sp. and Plesiodipus wangae nov. sp., show noticeable evolutionary trends. These species display more derived dental characters than their European contemporaries, in which they are much more comparable to Miocene forms. This observation reinforces the assumed early diversification of cricetids in this part of Asia. A striking case of sympatric evolution is indicated by the similarity of size and dental morphology of two sibling species, Eucricetodon asiaticus and Eucricetodon jilantaiensis nov. sp. Other taxa such as Witenia yolua nov. sp., Pseudocricetops matthewi nov. gen., nov. sp. and a primitive Tachyoryctoidinae, are scarcely represented and present unusual morphologies. The Cricetidae from Ulantatal also provide evidence suggesting faunal exchanges between Asia and Europe through the Paratethyan pathway during the second half of the Paleogene.

New remains of Astraponotus (Mammalia, Astrapotheria) and considerations on Astrapothere cranial evolution

Astraponotus Ameghino, 1901, the only valid Mustersan (late Eocene) astrapothere, typifies the Ameghino’s “Capas Astraponotenses”. This taxon is traditionally interpreted as structurally ancestral to all the Oligocene–Miocene astrapotheriids. However, it was imperfectly known: only isolated teeth and very partial mandibles have hitherto been described. In this contribution we provide the first description of the skull, mandible, and complete dentition of Astraponotus based on new materials from the Gran Hondonada and other Mustersan localities in central Patagonia, Argentina. The features observed in the dentition of Astraponotus are intermediate between the Casamayoran (middle Eocene) and the Oligocene–Miocene astrapotheres in the degree of hypsodonty, reduction of the dental formula, and development of accessory occlusal elements. Concordantly, the skull retains some plesiomorphies, also observed in Trigonostylops, whereas the auditory region and the basicranium are much closer to those of Parastrapotherium, Astrapotherium, and Granastrapotherium. On the other hand, the skull of Astraponotus differs from all known astrapotheres by the disproportioned height and narrowness of the braincase, the extreme reduction of the nasals and the premaxillaries, the absence of anteorbital rim, and the reduction of the frontal region. Some of these features represent cranial specializations exactly opposite to that of Astrapotherium. These characters look astonishingly derived for an Eocene astrapothere, suggesting that extreme cranial specializations occurred independently during the evolution of the order, and that Astraponotus represents a distinctive lineage from that of Astrapotherium and other Miocene forms.

Khoratpithecus piriyai, a Late Miocene hominoid of Thailand

A Khoratpithecus piriyai lower jaw corresponds to a well-preserved Late Miocene hominoid fossil from northeastern Thailand. Its morphology and internal structure, using a microcomputed tomography scan, are described and compared to those of other known Miocene hominoids. It originated from fluviatile sand and gravel deposits of a large river, and was associated with many fossil tree trunks, wood fragments, and large vertebrate remains. A biochronological analysis by using associated mammal fauna gives an estimated geological age between 9-6 Ma. The flora indicates the occurrence of a riverine tropical forest and wide areas of grassland. K. piriyai displays many original characters, such as the great breadth of its anterior dentition, suggesting large incisors, large lower M3, a canine with a flat lingual wall, and symphysis structure. Several of its morphological derived characters are shared with the orangutan, indicating sister-group relationship with that extant ape. This relationship is additionally strongly supported by the absence of anterior digastric muscle scars. These shared derived characters are not present in Sivapithecus, Ankarapithecus, and Lufengpithecus, which are therefore considered more distant relatives to the orangutan than Khoratpithecus. The Middle Miocene K. chiangmuanensis is older, displays more primitive dental characters, and shares several dental characters with the Late Miocene form. It is therefore interpreted as its probable ancestor. But its less enlarged M3 and more wrinkled enamel may suggest an even closer phylogenetic position to orangutan ancestors, which cannot yet be supported because of the incomplete fossil record. Thus Khoratpithecus represents a new lineage of Southeast Asian hominoids, closely related to extant great ape ancestors.

METAPHIOMYS (RODENTIA: PHIOMYIDAE) FROM THE PALEOGENE OF SOUTHWESTERN TANZANIA

[Extract] The evolutionary history of the living African rodent families is a topic of considerable debate, yet it is generally agreed that the modern cane rats (Thryonomys Fitzinger, 1867) and dassie rats (Petromus Smith, 1831) have an evolutionary history within the infraorder Phiomorpha (e.g., Wood, 1968). Phiomorphs possess hystricognathous mandibular morphology, multiserial incisor enamel, and hystricomorphous attachment of the masseteric musculature (e.g., Lavocat, 1978; Holroyd, 1994). In his initial work on the group, Wood (1968) placed all phiomorph taxa into a single family, and named a handful of morphologically diverse species based mainly on size. Lavocat (1978) later revised the taxonomy of the group, raising many of the differences among species to the family level. More recently, Holroyd (1994) observed that these contrasting views likely stemmed from the fact that Wood's phiomorph work emphasized the overall similarity of Paleogene specimens from the Fayum of Egypt, whereas Lavocat endeavored to explain the diverse Miocene rodent faunas from East Africa, envisioning that each of the Miocene forms had an ancestor among the Paleogene taxa. In this paper we adopt Holroyd's (1994) revised version of family-level relationships among the phiomorphs. A variety of well-preserved specimens pertaining to phiomorph evolutionary history have been described from the Paleogene of northern Africa and Oman (Osborn, 1908; Wood, 1968; Jaeger et al., 1985; Fejfar, 1987; Holroyd, 1994) and Asia (e.g., Flynn et al., 1986; Jaeger, 1988; Marivaux et al., 2002; Marivaux and Welcomme, 2003). However, Paleogene terrestrial deposits in sub- Saharan Africa are extremely rare, hence this constitutes the earliest phiomorph record from East Africa. Here we announce a new microsite in the Mbeya Region of southwestern Tanzania, preserving Metaphiomys Osborn, 1908, a rodent taxon previously described exclusively from the early Oligocene of Egypt, Libya, and Oman (Wood, 1968; Fejfar, 1987; Thomas et al., 1989). Not only does this represent a significant geographic extension of the taxon, it also constitutes the first rodent material described from the Paleogene of East Africa.

Sequence of the Cenozoic Mammalian Faunas of the Linxia Basin in Gansu, China

Abstract In the Linxia Basin on the northeast margin of the Tibetan Plateau, the Cenozoic strata are very thick and well exposed. Abundant mammalian fossils are discovered in the deposits from the Late Oligocene to the Early Pleistocene. The Dzungariotherium fauna comes from the sandstones of the Jiaozigou Formation, including many representative Late Oligocene taxa. The Platybelodon fauna comes from the sandstones of the Dongxiang Formation and the conglomerates of the Laogou Formation, and its fossils are typical Middle Miocene forms, such as Hemicyon, Amphicyon, Platybelodon, Choerolophodon, Anchitherium, and Hispanotherium. The Hipparion fauna comes from the red clay of the Liushu and Hewangjia Formations, and its fossils can be distinctly divided into four levels, including three Late Miocene levels and one Early Pliocene level. In the Linxia Basin, the Hipparion fauna has the richest mammalian fossils. The Equus fauna comes from the Wucheng Loess, and it is slightly older than that of the classical Early Pleistocene Nihewan Fauna. The mammalian faunas from the Linxia Basin provide the reliable evidence to divide the Cenozoic strata of this basin and correlate them with European mammalian sequence.

New Chalicotheriidae (Perissodactyla, Mammalia) from the Late Miocene of Bulgaria

ABSTRACT Few fossils have been described from the very rich localities of Kalimantsi in southwestern Bulgaria, and none from Hadjidimovo, in the same area. These deposits have produced one of the best collections of Chalicotheriidae from the late Miocene of Europe, increasing the diversity of the family, and providing the first definite evidence of the co-occurrence of both subfamilies, Chalicotheriinae and Schizotheriinae. The milk dentition of Ancylotherium is described for the first time; it confirms that this genus is close to, but different from, the American Tylocephalonyx. A chalicotheriine skull from Kalimantsi, with a characteristic tooth morphology, is referred to a new genus and species, Kalimantsia bulgarica. A revision of the taxonomy and systematics of European Chalicotheriinae leads us to discard “Macrotherium,” which is a junior synonym of Chalicotherium, to revive Anisodon Lartet for middle Miocene forms, and to suggest the extension of Kalimantsia into the latest Miocene of the Balkans.

ARCHAIASINIDS AND RELATED PORCELANEOUS LARGER FORAMINIFERA FROM THE LATE MIOCENE OF THE DOMINICAN REPUBLIC

Exceptionally large quantities of outstandingly well-preserved, free specimens of larger foraminifera from late Miocene sediments of the Dominican Republic invite an analysis of their structure in detail. The structures of the porcelaneous larger foraminifera reveal that most of them are not candidates for a direct ancestry of the species living today in the Caribbean. Although the late Miocene period has produced Caribbean endemists, in particular within the agglutinated group of the textulariellids and the lamellar-perforate group of the amphisteginids, the porcelaneous archaiasines and soritines are more closely related to the early Miocene forms of the Neotethys than to the Recent Caribbean endemists. These relationships are derived from their relative structural similarity and call for the proposition of appropriate additional taxa on the generic and specific levels. Miocene Miarchaias new genus develops several centimeters large, cyclical agamonts with meandropsinid structures covering the lateral surface of the disc (M. meander new species) whereas species of smaller shell size do not have cyclical generations (M. modestus new species). On the other hand, populations of cyclical schizonts and/or gamonts exhibit structures similar to the Recent, spiral Androsina: Androsinopsis radians new genus and species. The other new taxa erected here, Annulosorites spiralis new genus and species and Cyclorbiculina miocaenica new species, reflect differences in the apertural face and the respective arrangement of radial partitions as used to differentiate Recent Sorites from Amphisorus. Specimens to be attributed to the genera Cycloputeolina and Parasorites are present in the late Miocene of the Dominican Republic. They exhibit an exoskeleton in contrast to true soritids, and will need an eventual worldwide revision on the species level.

Archaiasinids and related porcelaneous larger foraminifera from the late Miocene of the Dominican Republic

Exceptionally large quantities of outstandingly well-preserved, free specimens of larger foraminifera from late Miocene sediments of the Dominican Republic invite an analysis of their structure in detail. The structures of the porcelaneous larger foraminifera reveal that most of them are not candidates for a direct ancestry of the species living today in the Caribbean. Although the late Miocene period has produced Caribbean endemists, in particular within the agglutinated group of the textulariellids and the lamellar-perforate group of the amphisteginids, the porcelaneous archaiasines and soritines are more closely related to the early Miocene forms of the Neotethys than to the Recent Caribbean endemists. These relationships are derived from their relative structural similarity and call for the proposition of appropriate additional taxa on the generic and specific levels. Miocene Miarchaias new genus develops several centimeters large, cyclical agamonts with meandropsinid structures covering the lateral surface of the disc (M. meander new species) whereas species of smaller shell size do not have cyclical generations (M. modestus new species). On the other hand, populations of cyclical schizonts and/or gamonts exhibit structures similar to the Recent, spiral Androsina: Androsinopsis radians new genus and species. The other new taxa erected here, Annulosorites spiralis new genus and species and Cyclorbiculina miocaenica new species, reflect differences in the apertural face and the respective arrangement of radial partitions as used to differentiate Recent Sorites from Amphisorus. Specimens to be attributed to the genera Cycloputeolina and Parasorites are present in the late Miocene of the Dominican Republic. They exhibit an exoskeleton in contrast to true soritids, and will need an eventual worldwide revision on the species level.