Systematic revision of the Late Miocene sabre‐toothed felid Paramachaerodus in Spain

Abstract: A systematic revision of the sabre‐toothed cat genus Paramachaerodus  Pilgrim, 1913 is presented. Two species are recognized within Paramachaerodus, Pa. orientalis, and Pa. maximiliani, and the genus Promegantereon  Kretzoi, 1938 is retrieved to include Promegantereon ogygia. Material from the Turolian Spanish localities of Crevillente‐2 (MN 11, Alicante) and Las Casiones (MN 13, Teruel), which was previously assigned to Paramachaerodus, is now included in the tribe Metailurini. The exceptional discoveries at the Spanish Vallesian (MN 10, Madrid) fossil site of Batallones‐1 have made it possible to characterize the dentition and cranial anatomy of a previously very poorly known machairodontine cat, formerly included in Paramachaerodus as Pa. ogygia, which now can be distinguished from Pa. orientalis and Pa. maximiliani by the following features: canines without crenulations, P3 with a marked disto‐lingual expansion, P4 without ectostyle and with a well‐developed protocone, M1 bucco‐lingually elongated and double‐rooted, m1 with a larger talonid, and primitive mandible morphology. Thus, the population from Batallones‐1 constitutes a clearly different form from the genus Paramachaerodus, and we propose its inclusion in the genus Promegantereon  Kretzoi, 1938 , together with an upper canine from Crevillente‐2 (MN 11), very similar to those from Batallones‐1. In contrast, Pa. orientalis shows the following apomorphies: crenulated canines, P3 reduced in size and without disto‐lingual expansion, P4 with a clear ectostyle as well as a reduced, backwardly displaced protocone and with a rounded and single‐rooted M1. The species Pa. maximiliani is characterized by its slightly larger size, crenulated canines, very elongated P3 with a moderate disto‐lingual expansion and P4 and M1 similar to those of Pa. orientalis. Paramachaerodus orientalis is recorded at Puente Minero (MN 11, Teruel), Concud (MN 12, Teruel), Crevillente‐15, and Crevillente‐16 (both MN 12, Alicante), and Paramachaerodus maximiliani in Venta del Moro (MN 13, Valencia). The available data suggest that Pr. ogygia was present in the Iberian Late Vallesian and Early Turolian faunas (MN 10 and MN 11) but disappeared after that age. Paramachaerodus was present in the faunas throughout the Turolian, with the species Pa. orientalis and Pa. maximiliani, this latter being probably part of the same immigration event that occurred in the Late Turolian and involved other mammal taxa such as camelids and ursids.     

Hipparion material from Gaojiashan locality in the Late Miocene of Linxia Basin,Gansu, China and associated mammalian fossil assemblage

Two Hipparion species, H. forstenae and H. hippidiodus from Gaojiashan locality in the Linxia Basin, Gansu, China are described in this paper, with the first presence of the former in the Linxia Basin. The lower cheek teeth of Hipparion from Gaojiashan bear deep ectoflexids, and after comparisons to other Chinese Hipparion fossils with deep ectoflexids, the mandibles with deep ectoflexids on the lower premolars suggest their attributions to H. forstenae. The presence of a deep ectoflexid on p2 may be interpretable as an intraspecifically variable feature in H. forstenae, and can also be found in H. dermatorhinum. Besides the Hipparion material, at least 8 species of large mammals occur at the Gaojiashan locality, including Adcrocuta eximia, Chilotherium wimani, Shansirhinus ringstroemi, Eucladoceros cf. proboulei, Palaeotragus cf. coelophrys, Giraffidae gen. et sp. indet., and the previously studied Promephitis hootoni and Eostyloceros hezhengensis. Although the sample from Gaojiashan shares five species with the Yangjiashan fauna, the Gaojiashan fossil assemblage may date to the Baodean because of the presence of H. forstenae. The overall taxonomic composition of the Gaojiashan assemblage at least suggests an approximate Baodean age, which would imply survival of C. wimani into the Baodean of the Linxia Basin.     

New insights on Cricetodontini (Rodentia,Mammalia) from the Duero Basin,Spain

Abstract

The tribe Cricetodontini is a common cricetid group found in several European basins from the Miocene. Here we present a study of the fossils of this group found in the Duero Basin. We updated the biostratigraphical assignation of some of the localities in which several species of Cricetodontini have been found. Cricetodontini remains from eight localities from the central sector of the Duero Basin have been described, measured and assigned to a species. The presence in these localities of Hispanomys aguirrei, H. lavocati, H. nombrevillae and H. aragonensis has allowed correlating them to the biostratigraphic scale built for the Miocene in Calatayud-Daroca Basin, identifying biozones G3, H and I (MN7/8 – MN10, Late Aragonian – Early Vallesian, Middle – Late Miocene). Furthermore, this study constitutes the first citation of this species in this basin, except H. aguirrei, previously described in the Duero Basin. After this work, the biostratigraphical assignation of the studied sites is now well known. We evidenced the resemblance of Duero and Calatayud-Daroca basins.     

The pliocene species of Hipparion andtheir biostratigraphical meanings

During the Pliocene, the «Hipparion fauna in the Mediterranean area decreased sharply in comparison with the Upper Miocene. Nevertheless, this species can be used to represent the Hipparion biozones in order to compare them with the mammal units. H. gromovae characterizes the Ventian or MN 13 mammal unit; H. crassum the Ruscinian or the Lower Pliocene or MN 14 unit; H. fissurae the Upper Ruscinian or the Lower Pliocene, MN 15; H. rocinantis, the Middle Pliocene or Lower Villafranchian, MN 16a. This distribution can be correlated in most of the Eurasian region.     

A non‐aquatic otter (Mammalia,Carnivora, Mustelidae) from the Late Miocene (Vallesian,MN 10) of La Roma 2 (Alfambra,Teruel, Spain): systematics and functional anatomy

A new genus and species of otter‐like mustelid, Teruelictis riparius, is created on the basis of a partial skeleton from the Late Miocene (Vallesian age, MN 10) locality of La Roma 2 (Teruel, Spain), including several postcranial elements, the skull, and the mandible. The combination of a typically lutrine dentition, similar to that of other fossil otters such as Paralutra jaegeri, with a very slender postcranial skeleton, including a long back and gracile long bones and metacarpals, thus lacking any aquatic adaptations, was previously unknown in the fossil record. This mosaic of features strongly suggests the possibility that the aquatic lifestyle of otters could have appeared after the initial development of the distinctive dental morphology of this specialized group of mustelids. © 2013 The Linnean Society of London     

Late Miocene Erinaceinae from the Teruel Basin (Spain)

Classifying fossil teeth of Erinaceinae (spiny hedgehogs) is a challenging task, because of their scanty record and systematic treatment that heavily relies on skull characteristics. In this paper we describe the complete set of isolated dental elements of Erinaceinae from the upper Miocene sediments of the Teruel Basin (eastern Central Spain). Four different species were recognized: Postpalerinaceus cf. vireti, Atelerix aff. depereti, Atelerix steensmai nov. sp., and a form classified as Erinaceinae genus and species indet. All four are relatively derived in showing multi-purpose dentitions, not showing only adaptations to insectivory, but also to carnivory, herbivory and possibly durophagy/malacophagy. The temporal occurrence of spiny hedgehogs during the middle to late Miocene in the Teruel Basin and neighboring Calatayud-Montalbán Basin peaks within periods of relative aridity, a correlation consistent with modern geographic distribution. Messinian cooling is the best candidate for explaining a remarkable demise of Erinaceinae at 7 Ma.     

Helminth communities of the Turkish endemic fish,Pseudophoxinus crassus (Ladiges, 1960): four helminth parasites for a new host record

Tuz Gölü (Salt Lake) Basin is one of the largest hypersaline lakes in the world and of extremely high biological importance owing to its high diversity and high level of endemism. It is hypothesized that the basin environment and the endemism of Pseudophoxinus crassus – a species of ray‐finned fish in the Cyprinidae family and found only in Turkey – might contribute to the host‐specific parasite characters. A total of 92 P. crassus specimens were collected by electrofishing between spring 2009 and autumn 2010 from the ?ncesu Stream in Konya Province, Turkey. By the end of the study period, four parasitic helminth species (Gyrodactylus latus, Asymphylodora imitans, Bothriocephalus acheilognathi and Pomphorhynchus laevis) were recorded. All had been reported previously from other hosts (non‐host specific). Among these parasites G. latus and A. imitans are new records for the helminth fauna of Turkey. Prevalence and infestation intensity, length classes, and sex compositions of infested populations, as well as the seasonality of infestation were obtained and the results compared with other studies.     

Late Emsian Rutoceratoidea (Nautiloidea) from the Prague Basin,Czech Republic: morphology,diversity and palaeoecology

Abstract: Nautiloids of the superfamily Rutoceratoidea from the late Emsian (late Early Devonian) of the Prague Basin (Czech Republic) are commented upon. Species recognized include the hercoceratids Hercoceras mirum, H.? transiens, Ptenoceras proximum, P. nudum, P. minusculum and Anomaloceras anomalum, as well as the rutoceratids Adelphoceras bohemicum, Homoadelphoceras devonicans, Pseudorutoceras bolli and Goldringia? devonicans. In addition, four new species are described: Parauloceras regulare sp. nov., Roussanoffoceras chlupaci sp. nov., Otomaroceras sp. nov. and Goldringia sp. nov. Morphology and distribution patterns of Pragian and late Emsian rutoceratoid faunas from the Prague Basin are compared. They show that an increased diversity was accompanied by a higher level of specialization of rutoceratoids, which manifested itself in low abundance, increased facies dependence and greater variation in shell size during the Early Devonian. The evolution of sculpture and a contracted aperture, both regarded as protective adaptive features, was also examined, but no adaptive trend towards more pronounced sculpture and constriction of the aperture was found to have occurred in the Early Devonian. A more distinctive sculpture was, however, observed in shallow‐water assemblages of P. proximum in comparison with deeper‐water faunules, and two additional cephalopod species were examined in order to obtain comparative data. The presence of distinct sculpture patterns in coeval shallow‐ and deeper‐water assemblages suggests limited migration between them and consequently reflects some degree of territoriality in Devonian nautiloids. New data on early shell development in P. proximum are presented. During the Chote? Event, rutoceratoid generic diversity dropped dramatically, one family became extinct and the Early Devonian diversification of the group came to an end. The recovery of nautiloid faunas was slower than that of other cephalopods and associated, unrelated invertebrates. The absence of change in abundance patterns between Pragian and late Emsian rutoceratoid faunas, i.e. prior to and subsequent to ammonoid radiation, suggests that the appearance and radiation of the latter group in the early Emsian did not affect the structure of nautiloid assemblages, i.e. these two clades did not occupy the same niches.     

Taxonomic review of the New World tamarins (Primates: Callitrichidae)

Twelve generic names have been ascribed to the New World tamarins but all are currently placed in just one: Saguinus Hoffmannsegg, 1807. Based on geographical distributions, morphology, and pelage patterns and coloration, they have been divided into six species groups: (1) nigricollis, (2) mystax, (3) midas, (4) inustus, (5) bicolor and (6) oedipus. Molecular phylogenetic studies have validated five of these groups; each are distinct clades. Saguinus inustus is embedded in the mystax group. Genetic studies show that tamarins are sister to all other callitrichids, diverging 15?13 Ma. The small‐bodied nigricollis group diverged from the remaining, larger tamarins 11?8 Ma, and the mystax group diverged 7?6 Ma; these radiations are older than those of the marmosets (Callithrix, Cebuella, Mico), which began to diversify 6?5 Ma. The oedipus group diverged from the midas and bicolor groups 5?4 Ma. We review recent taxonomic changes and summarize the history of the generic names. Taking into account the Late Miocene divergence time (11?8 Ma) between the large‐ and small‐bodied tamarin lineages, the small size of the nigricollis group species when compared with other tamarins, and the sympatry of the nigricollis group species with the larger mystax group species, we argue that the nigricollis group be recognized as a distinct genus: Leontocebus Wagner, 1839.     

Gliridae (Rodentia,Mammalia) with a simple dental pattern: a new genus and new species from the European Early and Middle Miocene

A new genus of Gliridae, Simplomys gen. nov. is proposed. It contains glirids with a simplified dental pattern from the European Early and Middle Miocene. Simplomys gen. nov. includes several species originally described as Pseudodryomys such as Simplomys simplicidens, Simplomys robustus, Simplomys julii, and Simplomys aljaphi. In addition, a new species, Simplomys meulenorum sp. nov. , is proposed from the Spanish Miocene. The species of this genus share not only a very reduced and simplified dental morphology, but also unique dental proportions that clearly separate them from any other genera of Gliridae. Simplomys gen. nov. is recorded in most of the fossil faunas from the Early and Middle Miocene of the Iberian Peninsula, and shows the maximum diversity in this area during Mammal Neogene Zones MN 3 and MN 4. The genus has been also recorded in other European countries such as France, Germany, and Switzerland, conferring to this very characteristic taxon an important role for biochronological correlations within the European continent. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 157 , 622–652.     

First record of Latonia gigantea (Anura,Alytidae) from the Iberian Peninsula

The single extant species of the anuran genus Latonia lives in Israel, but in the fossil record the genus is known mainly from Europe, spanning from the Oligocene to the early Pleistocene. Here we describe new remains of Latonia from the early to late Miocene of the Vallès-Penedès Basin (NE Iberian Peninsula), coming from the following localities: Sant Mamet (MN4), Sant Quirze and Trinxera del Ferrocarril (MN7+8), and Castell de Barberà, Can Poncic 1 and Can Llobateres 1 (MN9). Fossils from the late Aragonian and early Vallesian are attributed to Latonia gigantea mainly because of the morphology of the ornamentation that covers the maxillae. In turn, an ilium from Sant Mamet is not diagnostic at the specific level and is assigned only to the genus Latonia. The newly reported remains represent the first record of L. gigantea in the Iberian Peninsula, where Latonia was previously known by a single report of Latonia cf. ragei from Navarrete del Río (MN2) and remains from other localities unassigned to species. Moreover, the Vallès-Penedès remains represent one of the southernmost records of the species known thus far. The presence of Latonia in these localities confirms the humid and warm environment suggested by the recorded mammal fauna.     

Revision of Mecinus heydenii species complex (Curculionidae): integrative taxonomy reveals multiple species exhibiting host specialization

A combined taxonomic, morphological, molecular and biological study revealed that the species presently named Mecinus heydenii is actually composed of five different species: M. heydenii Wencker, 1866; M. raphaelis Baviera & Caldara sp. n., M. laeviceps Tournier, 1873; M. peterharrisi To?evski & Caldara sp. n. and M. bulgaricus Angelov, 1971. These species can be distinguished from each other by a few subtle characteristics, mainly in the shape of the rostrum and body of the penis, and the colour of the integument. The first four species live on different species of Linaria plants, respectively, L. vulgaris (L.) P. Mill., L. purpurea (L.) P. Mill. L. genistifolia (L.) P. Mill. and L. dalmatica (L.) P. Mill., whereas the host plant of M. bulgaricus is still unknown. An analysis of mtCOII gene sequence data revealed high genetic divergence among these species, with uncorrected pairwise distances of 9% between M. heydenii and M. raphaelis, 11.5% between M. laeviceps, M. heydenii and M. raphaelis, while M. laeviceps and M. peterharrisi are approximately 6.3% divergent from each other. Mecinus bulgaricus exhibits even greater divergence from all these species and is more closely related to M. dorsalis Aubé, 1850. Sampled populations of M. laeviceps form three geographical subspecies: M. laeviceps laeviceps, M. laeviceps meridionalis To?evski & Jovi? and M. laeviceps corifoliae To?evski & Jovi?. These subspecies show clear genetic clustering with uncorrected mtDNA COII divergences of approximately 1.4% from each other.     

Rodents, insectivores and chiropterans (Mammalia) from the late Aragonian of Can Missert (Middle Miocene, Vallès-Penedès Basin, Spain)

In this paper, the insectivores, chiropterans and rodents from the middle Miocene site of Can Missert are described. The faunal list of this locality includes the following species: Miosorex grivensis, Desmanella sp., Talpidae indet., Vespertilionidae indet., Hispanomys daamsi, Megacricetodon minor, Megacricetodon ibericus, Fahlbuschia crusafonti, Democricetodon brevis nemoralis, Eumyarion medium, Muscardinus hispanicus, Eomuscardinus sp., Paraglirulus werenfelsi and Spermophilinus bredai. H. daamsi is a new Cricetodontine species which is characterized by complete ectolophs and relatively long third lower molars. The rodent association of Can Missert enable one to assign this locality to the late Aragonian, MN 8, being close in age to other localities in the Vallès-Penedès Basin such as Castell de Barberà. However, the proportion in which each species is represented is very different in the two cases. This evidence points to the existence climatic pulses at the end of the Aragonian Mammal-Stage.     

Feeding preferences of <Emphasis Type="Italic">Gomphotherium subtapiroideum</Emphasis> (Proboscidea,Mammalia) from the Miocene of Sandelzhausen (Northern Alpine Foreland Basin,southern Germany) through life and geological time: evidence from dental microwear analysis

The objective of this study is to estimate changes in feeding preferences of the proboscidean species Gomphotherium subtapiroideum (Schlesinger 1917) by means of dental microwear analyses. The dietary changes are first evaluated through the ontogeny of this species, between juveniles and adults, and are then studied through geological time, from early Middle Miocene (MN5) to middle Late Miocene (MN8–9) localities of the German Molasse Basin. The microwear patterns of juvenile and adult individuals of G. subtapiroideum from Sandelzhausen (MN5) differ merely by the variable “length of scratches”, emphasizing longer jaw movements during mastication in adults. The microwear signatures of G. subtapiroideum do not vary significantly between the two geological time periods studied, but reflect mixed feeding preferences in both cases. These results imply that, despite an important environmental change at that time (drying and opening), the ecology of G. subtapiroideum and, especially, its feeding habits were not affected. Its dental microwear pattern is then compared with those of other species of Proboscidea from the Middle-Late Miocene of Germany, namely Deinotherium giganteum and Gomphotherium steinheimense.     

A synopsis of the late Miocene Mammal Fauna of Samos Island,Aegean Sea,Greece

As one of the oldest known Eurasian fossil vertebrate localities, Samos late Miocene fauna attracted the interest of specialists by its richness and overall importance. Nevertheless, crucial taxonomical questions and chronological problems obscured its value. The detailed study of the local stratigraphy, the collection of new fossil material and its study, the revision of the old collections and the updated magneto-chronology of the fossiliferous deposits permited to re-discuss most of the problems in a special volume edited in 2009 by Koufos and Nagel and to provide a clearer and more precise idea about the Samos fauna and its age. A synopsis of this work is given here. The systematic study of the new collection (～1200 identified specimens) allows the determination of 42 species from three fossil horizons, ranging from the upper part of early Turolian (MN11) to the end of middle Turolian (MN12). Taxonomic novelties are the presence of the carnivore genus Protictitherium found for the first time in Samos, the establishment of the new name Skoufotragus for Pachytragus Schlosser with the new species Skoufotragus zemalisorum, and the amended morphology of Pseudomeriones and Urmiatherium. Additionally six Hipparion and four Gazella species were recognized and a better morphometric distinction between Samotherium boissieri and Samotherium major was performed. This study also improved the correlation of the old fossiliferous sites with the new ones and with the local stratigraphy of the Mytilinii Basin, while precise ages have been obtained for the mammal localities. The new data together with the old collections indicate the presence in Samos of four chronologically successive mammal assemblages reflecting a “four stages-of-evolution” scheme. The Turolian palaeoenvironment of Samos is determined as an open bushland with thick grassy-floor of C3 graminoids with possible increase of the open and dry character from the beginning to the end of Middle Turolian. The Samos mammal faunas are palaeobiogeographically closer to the Asian ones than to those from the Greek mainland.     

Dorlodotia and related genera (Rugosa) from the Visean (Mississippian; Carboniferous) of Zonguldak and Bartin (North‐Western Turkey)

Abstract: A rich and diverse coral fauna collected from the Livian (Viséan, Mississippian) of Zonguldak and Bart?n (North‐western Turkey) contains numerous specimens of Dorlodotia and related forms. The most common species, D. delepinei Charles, 1933 , is redetermined as Dorlodotia briarti, an European species. A new species of Dorlodotia is described for very large, phaceloid forms: D. euxinensis. The genus Ceriodotia is created for species close to Dorlodotia with a cerioid habit. It comprises two species: C. bartinensis and C. petalaxoides, both common in the Viséan of Zonguldak and Bart?n. Based on comparison of morphological characters and features of the astogeny, a phylogenetic lineage is proposed for Dorlodotia and the new taxa. The evolution of D. euxinensis from D. briarti is peramorphic. Subsequent paedomorphosis resulted in the lineage D. euxinensis–C. bartinensis–C. petalaxoides. Ceriodotia probably includes Viséan taxa from Asia previously described as ‘Acrocyathus’.     

Parasites and the island syndrome: the colonization of the western Mediterranean islands by Heligmosomoides polygyrus (Dujardin, 1845)

Aim Populations of free‐living vertebrates on islands frequently differ from their mainland counterparts by a series of changes in morphometric, life‐history, behavioural, physiological and genetic traits, collectively referred to as the ‘island syndrome’. It is not known, however, whether the ‘island syndrome’ also affects parasitic organisms. The present study establishes the colonization pattern of the Mediterranean islands by the nematode Heligmosomoides polygyrus, a direct and specific parasite of rodent hosts of the Apodemus genus, and evaluates the effects of island colonization by this species on two components of the island syndrome: the loss of genetic diversity and the enlargement of the ecological niche. Location Heligmosomoides polygyrus was sampled on seven western Mediterranean islands ? Corsica, Crete, Elba, Majorca, Minorca, Sardinia and Sicily ? as well as in 20 continental locations covering the Mediterranean basin. Methods The mitochondrial cytochrome b gene (690 base pairs) was sequenced in 166 adult H. polygyrus individuals sampled in the 27 continental and island locations. Phylogenetic reconstructions in distance, parsimony, maximum likelihood and Bayesian posterior probabilities were carried out on the whole cytochrome b gene data set. The levels of nucleotide, haplotype and genetic divergence (Kimura two‐parameter distance estimator) diversities were estimated in each island population and in the various continental lineages. Results Phylogenetic reconstructions show that the mainland origins of H. polygyrus were continental Spain for the Balearic Islands (Majorca, Minorca), northern Italy for the Tyrrhenian Islands (Corsica, Sardinia, Elba), southern Italy for Sicily, and the Balkan region for Crete. A comparison of island H. polygyrus populations with their mainland source populations revealed two characteristic components of the island syndrome in this parasite. First, island H. polygyrus populations display a significant loss of genetic diversity, which is related (r² = 0.73) to the distance separating the island from the mainland source region. Second, H. polygyrus exhibits a niche enlargement following insularization. Indeed, H. polygyrus in Corsica is present in both A. sylvaticus and Mus musculus domesticus, while mainland H. polygyrus populations are present exclusively in Apodemus hosts. Main conclusions Our results show that H. polygyrus has undergone a loss of genetic diversity and a niche (host) enlargement following colonization of the western Mediterranean islands. To our knowledge, this study provides the first evidence for components of the ‘island syndrome’ in a parasitic nematode species.     

Large apeomyine rodents (Mammalia,Eomyidae) from the early Miocene of Echzell,Germany

The dental material described in this paper was collected from fossiliferous ash layers of the Vogelsberg volcanic complex at Echzell, Germany. It consists of 32 teeth of a new large Apeomys species, Apeomys oldrichi n. sp., and 19 teeth of Megapeomys lindsayi Fejfar, Rummel and Tomida. Both species are extremely rare faunal elements in the early Miocene of Europe. Apeomys oldrichi n. sp. is the largest known Apeomys species, and occurs in a number of MN 3 – 4 sites in southern Germany and Czech Republic. Megapeomys lindsayi, the largest Eurasian apeomyine, was described on the basis of a single lower premolar. Herein both lower and upper cheek teeth as well as the lower deciduous premolar are described for the first time. In comparison with related populations from other localities, the evolutionary stage of the two apeomyine species clearly indicates a middle Orleanian age (MN 4) for Echzell which concurs with previous studies.

http://zoobank.org/urn:lsid:zoobank.org:pub:1F9E49BE-C4B6-4597-A116-234E13D86BA9     

Eomyidae fauna turnover at the Early-Middle Miocene boundary in the Morteral section (Magro Basin,Valencia, Spain)

The material of Eomyidae from three localities (Morteral 1, Morteral 20A and Morteral 22) of the Morteral section in the Magro Basin, eastern Spain, is described. These localities contain remains of Ligerimys and Eomyops. Morteral 1 is situated in the lowest part of the section and contains Ligerimys ellipticus, whereas Morteral 20A and Morteral 22 are situated in the middle part of the section and contain, among other rodent species, Eomyops noeliae. The youngest localities in the Morteral section (Morteral 41 and 44) record Megacricetodon collongensis, first representative of Megacricetodon in the Middle Miocene (MN5). The locality Morteral 20A contains Megacricetodon primitivus; Morteral 1 and Morteral 22 contain a form of Megacricetodon different from both M. primitivus and M. collongensis, therefore, these three localities are of lower Aragonian age (MN4). In the Aragonian type area, L. ellipticus is rare in zone B (lower part of MN4) and frequent in zone C (upper part of MN4). The first record of Eomyops in the Aragonian type area occurs in MN7/8 and in MN5 in Central Europe. The turnover of eomyid faunas in MN4 localities of the Morteral section clearly confirms the hypothesis of Engesser (1999) that Eomyops may have appeared earlier than supposed so far (MN5).