Deciduous dentition and eruption pattern in late Miocene Pachyrukhinae (Hegetotheriidae,Notoungulata) from La Pampa Province,Argentina

The study of juvenile remains of Paedotherium Burmeister from Cerro Azul Formation (La Pampa Province, Argentina; late Miocene) is presented. Upper and lower deciduous dentition (or permanent molars supposed to be associated with non-preserved deciduous teeth) are recognised. Several ontogenetic stages are distinguished among juveniles, according to the degree of wear and the replaced deciduous teeth. Besides, some morphological and metrical differences are observed along the crown height. Deciduous cheek teeth are high-crowned and placed covering the apex of the corresponding permanent tooth. The height of the crown and the degree of wear allow establishing the pattern of dental replacement of deciduous and permanent premolars in a posterior–anterior direction (DP/dp4–2 and P/p4–2), as well as the eruption of M/m3 before DP/dp4 is replaced. Some of the studied remains are recognised as young individuals of Tremacyllus Ameghino, but with complete permanent dentition, which leads to propose a different timing in the dental replacement with respect to Paedotherium; they also allow the establishment of an opposite premolar eruption pattern, from P/p2 to P/p4. This knowledge of the deciduous dentition of Paedotherium suggests the need of revising the morphological and metrical characters previously used for defining species within this taxon.     

New dental remains of Anoiapithecus and the first appearance datum of hominoids in the Iberian Peninsula

New dental remains of the fossil great ape Anoiapithecus brevirostris are described from the Middle Miocene local stratigraphic series of Abocador de Can Mata (ACM) in els Hostalets de Pierola (Vallès-Penedès Basin, NE Iberian Peninsula). These specimens correspond to maxillary fragments with upper teeth from two female individuals from two different localities: left P³–M¹ (IPS41712) from ACM/C3-Aj (type locality; 11.9 Ma [millions of years ago]); and right M¹–M² and left P⁴–M² (IPS35027) from ACM/C1-E* (12.3–12.2 Ma). Relative enamel thickness is also computed in the latter individual and re-evaluated in other Middle Miocene hominoids from ACM, in order to better assess their taxonomic affinities. With regard to maxillary sinus development, occlusal morphology, molar proportions and enamel thickness, the new specimens show greater resemblances with the (male) holotype specimen of A. brevirostris. They differ from Pierolapithecus catalaunicus in displaying less inflated crests, a more lingually-located hypocone, and relatively lower-crowned molars; from Dryopithecus fontani, in the relatively thicker enamel and lower-crowned molars; from Hispanopithecus spp., in the more inflated crown bases, less peripheral cusps and more restricted maxillary sinus; and from Hispanopithecus laietanus also in the thicker crests, more restricted occlusal foveae, and relatively lower-crowned molars. The new specimens of A. brevirostris show some slight differences compared with the holotype of this species: smaller size (presumably due to sexual size dimorphism), and less distally-tapering M² occlusal contour (which is highly variable in both extant and extinct hominoids). The reported remains provide valuable new evidence on dental intraspecific variation and sexual dimorphism in Anoiapithecus. From a taxonomic viewpoint, they support the distinction of this taxon from both Dryopithecus and Pierolapithecus. From a chronostratigraphic perspective, IPS35027 from ACM/C1-E* enlarges the known temporal distribution of Anoiapithecus, further representing the oldest record (first appearance datum) of hominoids in the Iberian Peninsula.     

A new species of Anchitherium (Equidae: Anchitheriinae) from the Middle Miocene of Abocador de Can Mata (Vallès-Penedès Basin, NE Iberian Peninsula)

Anchitherium nievei sp. nov. is erected on the basis of dentognathic remains from the late Aragonian (MN7+8, ca. 12.3–12.1 to 11.7–11.6 Ma, Middle Miocene) of three localities from the Abocador de Can Mata local stratigraphic series (els Hostalets de Pierola, Vallès-Penedès Basin, Catalonia, Spain). This taxon differs from endemic species of Anchitherium from the inner Iberian basins, most closely resembling A. aurelianense, A. hippoides and A. steinheimense by its marked brachyodonty and small dental size, although differing by dental proportions and several details of occlusal morphology. From a paleoenvironmental viewpoint, the presence of this taxon fits well with previous inferences that indicated a relatively closed and humid forested habitat, more similar to that of similarly aged French localities.     

Desmaninae (Talpidae, Mammalia) from the Pliocene of Tollo de Chiclana (Guadix Basin, Southern Spain): Considerations on the phylogeny of the genus Archaeodesmana

The fossil Desmaninae (water-moles) from the Pliocene continental deposits of Tollo de Chiclana (Guadix Basin, Southern Spain) are described. A new species, Archaeodesmana elvirae, is defined from the locality of Tollo de Chiclana-1 (upper Ruscinian). This species is characterized by relatively small canines and premolars (except the P4) and large P4 and molars, besides several morphological features. The presence of Archaeodesmana brailloni is reported from the locality of Tollo de Chiclana-1B (uppermost Ruscinian). A small sample assigned to the genus Archaeodesmana is described from the lower Villafranchian site of Tollo de Chiclana-3, which cannot be determined at the specific level. The phylogenetic relationships between the different species of Archaeodesmana are reconsidered in the light of the recent findings, which support the idea of a more complex phylogeny than previously proposed for this genus. The populations from the Guadix Basin, previously assigned to Dibolia dekkersi (= Archaeodesmana getica), are here considered to belong to a different (unnamed) species, which is the ancestor of A. elvirae. On the other hand, the new species A. elvirae is proposed as the ancestor of A. brailloni.     

First giraffid skulls (Bohlinia attica) from the late Miocene Maragheh fauna,Northwest Iran

An almost complete skull and a second partial skull of Bohlinia attica (Artiodactyla: Giraffidae) from the late Miocene of Maragheh in northwestern Iran is described along with a complete upper dentition from Samos in Greece. These specimens enrich what is known of this species. The skull has massive bent ossicones. The braincase is horizontal to the face in lateral view. The upper premolars have strongly curved styles. The metapodials of this species are elongate with a deep plantar trough. The braincase is short and the occipital does not extend caudally. The type material of Bohlinia is from Pikermi but this taxon is also known from localities in F.Y.R.O. Macedonia, Greece, Turkey, Bulgaria, Iraq, and Iran. The new specimens are similar to others except that the ossicone terminates in a knob and the palatine choanae are positioned caudally. This taxon along with Honanotherium, which is most similar but with shorter metapodials and simpler premolars, can be placed in the subfamily Bohlininae.     

New Study on Dental and Skeletal Features of the Cretaceous “Symmetrodontan” Mammal Zhangheotherium

A new partial skeleton of the Cretaceous “symmetrodontan” mammal Zhangheotherium quinquecuspedens from the Yixian Formation of Liaoning, China has shed light on the dental and skeletal features of this taxon. The new fossil is a juvenile individual of late growth stage, preserved with interesting features of the premolar replacement. This fossil also provides new information on the vertebral column, the pelvis, the hindlimb and pes. Zhangheotherium has a typical diphyodont replacement of its premolars that is characterized by an alternating pattern (p1 → p3 → p2). This alternating replacement of premolars is a derived condition shared by Dryolestes, Slaughteria, and some basal eutherians, and differs from the plesiomorphic sequential replacement of anterior postcanines in eutricondontans, in most multituberculates and in stem mammaliaforms. The calcaneus and astragalus in the ankle joint of Zhangheotherium lack superposition. This shows that the trechnotherian clade, of which Zhangheotherium is a basal taxon, has retained the primitive condition of mammaliaforms in which the astragalus is in juxtaposition with the calcaneus. Coupled with recent evidence from the earliest metatherians and eutherians, this suggests that the superposition of astragalus and calcaneus evolved in parallel in metatherians and eutherians.     

Peltoceratinae (Ammonoidea) from the upper Callovian–lower Oxfordian of Kutch,India: Systematic revision and biostratigraphic implication

The ammonoid subfamily Peltoceratinae is a well-constrained group restricted to the Middle Upper Jurassic; it had a near global distribution. In Kutch (India), they were the most important marine macroinvertebrate group during the upper Callovian–lower Oxfordian. Previous reports suffered from excessive splitting due to failure to account for the large intraspecific variability and sexual dimorphism of these ammonoids. The present systematic revision, based on numerous specimens including many near-complete adult specimens, enables to recognize and describe three species of the genus Peltoceras (P. athleta, P. ponderosum, and P. kumagunense) and two species of the genus Peltoceratoides (P. semirugosus and P. propinquus), as well as identifying their macroconchs and microconchs. We rediscovered Peltoceras athleta, which was previously described by Waagen (1875) but often overlooked by subsequent workers. We were able to identify several morphs within this species that are stunningly similar with those previously reported from France. The presence of P. athleta sensu stricto prompted us to reinstate the Athleta Zone in Kutch, improving intercontinental biostratigraphic correlation. Also, it highlights that the genus Peltoceras has a different biostratigraphic longevity in Kutch: in Europe it is restricted to the upper Callovian, whereas in India it also occurs in the lower Oxfordian.     

Fossil remains of Macaca sylvanus florentina (Cocchi, 1872) (Primates, Cercopithecidae) from the Early Pleistocene of Quibas (Murcia, Spain)

The macaque material from the Early Pleistocene site of Quibas (Albanilla, Murcia, Spain), including dentognathic remains, isolated teeth and some postcranial bone fragments, is described. Both metrically and morphologically, this sample must be attributed to Macaca sylvanus (the Barbary macaque). This species is currently distributed through North Africa and Gibraltar, but was much more widely distributed during the Plio-Pleistocene, being represented by several European fossil subspecies. Metrical comparisons of dental size and proportions between extant M. s. sylvanus and fossil Macaca sylvanus florentina from the type locality and other Italian sites are undertaken, in order to classify the remains from Quibas at the subspecies level. The results show that the Quibas sample not only fits the range of variation of M. s. florentina from the type locality, but also differs from the extant Barbary macaque condition in several regards. This permits us to formally attribute the material from Quibas to M. s. florentina. The material described in this paper therefore significantly improves the knowledge of this fossil taxon, particularly regarding the upper dentition, and further confirms the taxonomic distinctiveness of this extinct taxon at the subspecies rank. Taken as a whole, M. s. florentina largely overlaps in dental dimensions with M. s. sylvanus, but differs from the latter by displaying (on average): (1) absolutely longer upper molars (especially M¹ and M³); (2) relatively wider upper molars (especially M¹ and M²); (3) longer M³ as compared with the M²; (4) absolutely longer M₁ and M₃; and (5) relatively narrower M₃.     

The Phylogenetic Affinities of the Enigmatic Mammalian Clade Gondwanatheria

Gondwanatheria is a group of extinct mammals known from the Cretaceous and Paleogene of Gondwana. Resolution of the phylogenetic affinities of gondwanatherians has proven problematical, with the group currently considered Mammalia incertae sedis. We briefly review the morphology of known gondwanatherians, and argue that isolated upper premolars and a partial dentary preserving a blade-like p4 originally referred to the ferugliotheriid gondwanatherian Ferugliotherium windhauseni but subsequently identified as Multituberculata incertae sedis do indeed belong to F. windhauseni. We also suggest that the recently described ?cimolodontan multituberculate Argentodites coloniensis, based on an isolated lower premolar, may in fact be an unworn p4 of Ferugliotherium or a closely related taxon. We present the first phylogenetic analyses to include gondwanatherians, using maximum parsimony and Bayesian methods. Both methods place Ferugliotherium and sudamericid gondwanatherians in a clade with cimolodontan and “plagiaulacidan” multituberculates, although relationships within this clade are largely unresolved. The Gondwanatheria + Multituberculata clade supported here may reflect the convergent evolution of similar dental features, but it is the best supported hypothesis based on currently available data. However, denser sampling of multituberculate taxa and the discovery of more complete gondwanatherian fossils will be required to clarify the precise relationship between gondwanatherians and multituberculates, specifically to determine whether or not gondwanatherians are members of Multituberculata. We hypothesize that the anterior molariforms of sudamericid gondwanatherians evolved from blade-like precursors similar to the p4 of Ferugliotherium, possibly in response to the appearance of grasses in Gondwana during the Cretaceous.     

A juvenile skull of Acerorhinus yuanmouensis (Mammalia: Rhinocerotidae) from the Late Miocene hominoid fauna of the Yuanmou Basin (Yunnan,China)

A unique juvenile skull bearing both milk premolars and unerupted but fully developed permanent premolars and molars (observed using X-ray microcomputed tomography), and some isolated upper cheek teeth, all from the Late Miocene hominoid fauna of the Yuanmou Basin (Yunnan, China), closely resemble craniodental material of Acerorhinus yuanmouensis Zong, 1998 from the same locality, and are referred to this species. A phylogenetic analysis based on 214 craniodental morphological characters scored for 31 terminal taxa reveals that A. yuanmouensis should be assigned to the genus Acerorhinus indeed. The newly discovered specimens improve our understanding of this species, especially with respect to the morphology of the milk premolars and premolars. Two intraspecific variations in the upper premolars are noted: a lingual bridge may be present or absent, and the lingual cingulum continuous or reduced. The analysis also indicates that: the phylogenetic status of Acerorhinus lufengensis Deng and Qi, 2009 should be reconsidered; “Aceratherium” huadeensis Qiu, 1979 does neither belong to Aceratherium nor Acerorhinus, and its phylogenetic status remains debatable.     

Caribbean Lower Tithonian ammonites from central-east Mexico

Imlay's ammonite species Paradontoceras butti and Paradontoceras antilleanum are first reported from central-east Mexico under precise stratigraphic control. Mexican and Cuban ammonites referred to these species have been studied and proved to have been gathered from a relatively limited area within the southern paleomargin of the north American Plate, which embraces eastern Mexico and north-western Cuba. The palaeontological examination, the multivariate analysis conducted on Mexican and Cuban data, the precise biostratigraphic and biogeographic control support the reinterpretation of Imlay's species P. antilleanum and P. butti. The latter has been designated the single, valid nominal species-level taxon which comprises the two species proposed by Imlay. The new genus Housaites has been created since the taxon Butticeras Houša is not available for taxonomic nomenclature. Housaites butti (Imlay) is upper Lower Tithonian (Semiforme/Verruciferum Zone of the Tethyan standard) in Mexico. The stratigraphic range in Cuba is not conclusively known.     

Effect of bovine blastocyst size at embryo transfer on day 7 on conceptus length on day 14: Can supplementary progesterone rescue small embryos?

Conceptus size on Day 14 after multiple embryo transfer of Day 7 in vitro–produced blastocysts varies greatly within animal. One explanation for this variation may be related to blastocyst cell number at the time of transfer. The aim of this study was to examine the effect of Day 7 blastocyst cell number on Day 14 conceptus size and to examine the effect of progesterone (P4) supplementation on embryo development after the transfer of Day 7 blastocysts containing a low total cell number. The estrous cycles of crossbred beef heifers were synchronized using an 8-day progesterone (P4)–releasing intravaginal device (PRID) with the administration of a prostaglandin F_2α analog on the day before device removal. Only those heifers recorded in standing estrus (Day 0) were used. Heifers were randomly assigned to one of four treatment groups: (1) control: large blastocysts (high total cell number), (2) control: small blastocysts (low total cell number), (3) small blastocysts plus a single intramuscular injection of 3000 IU human chorionic gonadotropin (hCG) on Day 2 after estrus, or (4) small blastocysts plus insertion of a vaginal P4 insert (PRID, 1.55 g P4) between Days 3 and 5 after estrus. In vitro–produced blastocysts were transferred to each heifer on Day 7 (n = 10 blastocysts per heifer), and conceptuses were recovered at slaughter on Day 14. Daily blood samples were collected from Day 0 to 14 to measure serum P4 concentrations. Data were analyzed using the PROC MIXED procedure of SAS. Total cell number on Day 7 was significantly lower in small versus large blastocysts (72.4 ± 3.93 vs. 144.8 ± 3.90, P < 0.05). Conceptus recovery rate was 53.8% overall (140 of 260) and was highest in the large blastocyst group (68.3%, 41 of 60) compared with the other groups (45.7%–55.0%). Concentrations of serum P4 were similar in the two unmanipulated recipient groups but were significantly elevated (P < 0.05) by Day 8 in the hCG-treated heifers and on Days 4 and 5 in the PRID group (P < 0.003). In the absence of supplemental P4, Day 14 conceptuses resulting from the transfer of small blastocysts (2.48 ± 0.54 mm) were smaller than those from large blastocysts (3.32 ± 0.52 mm). Administration of hCG on Day 2 approximately doubled conceptus length on Day 14 (4.94 ± 1.15 mm; P < 0.05), whereas insertion of a PRID from Days 3 to 5 increased conceptus length approximately fivefold (13.09 ± 2.11 mm; P < 0.05) compared with controls. In conclusion, results indicate that supplemental P4 is capable of “rescuing” poor-quality blastocysts, presumably via the now well-described actions on the endometrium and consequent effects on uterine lumen fluid composition.     

Anglesites gen. nov. (Ammonoidea, Ancyloceratina), un nouveau genre d’ammonites hétéromorphes du Barrémien supérieur du Sud-Est de la France

The revision of the Crioceras puzosianum d’Orbigny, 1842 made during the revision of the Paléontologie Française of d’Orbigny, shows that this taxon belongs to a new genus: Anglesites gen. nov. This new genus, from upper Barremian age, is monospecific for the moment and is homeomorphic to the Leptoceratoides from the Lower Barremian. It is temporarily included in the subfamily of the Leptoceratoidinae. A neotype for the “Crioceras” puzosianum d’Orbigny, 1842 is herein designated.     

The anatomy and systematic position of the early Miocene proconsulid from Meswa Bridge, Kenya

A small collection of fossil catarrhines was recovered from the early Miocene locality of Meswa Bridge in western Kenya between 1978 and 1980. The associated fauna from Meswa Bridge indicates an age older than 20 Ma. Much of the material has been briefly described previously, and its taxonomic status considered. The material can be assigned to a minimum of four individuals, all of which are infants or juveniles. Although the specimens were shown to belong to a distinct species of Proconsul, the taxon was not named, primarily because many of the specimens belonged to immature individuals. Nevertheless, the combined morphological features of the deciduous and permanent teeth allow the diagnosis of a new species of Proconsul, which is formally named here as P. meswae. It is a large-sized species, similar in dental size to P. nyanzae. The main features distinguishing it from all other previously named species of Proconsul are: incisors and deciduous incisors relatively low crowned; upper deciduous canines relatively higher crowned and more robust; molars and deciduous premolars relatively broader and higher crowned, with a more pronounced degree of buccolingual flare and better developed cingula; size differential between molars not as marked; dP₄ with a longer mesial fovea and smaller hypoconulid and distal fovea; P₄ relatively broader, with a better developed buccal cingulum; lower molars less rectangular with a longer mesial fovea, smaller distal fovea, more restricted talonid basin, and a tendency for a smaller hypoconulid; dP⁴ and upper molars with strongly buccolingually splayed roots; mandibular corpus in infants relatively deeper and more slender; maxilla with a well developed canine jugum and fossa. The broader and more flared molars with better developed cingula indicate that the Meswa Bridge species is more primitive than other species of Proconsul. The inference that it is a stem member of the Proconsul clade is consistent with the estimated age of the material.     

On the status of Isolophodon Roth, 1903 (Mammalia,Astrapotheria) and other little-known Paleogene astrapotheres from central Patagonia

Most of the 16 currently recognized astrapothere genera are well known through numerous specimens preserving at least almost complete dentition. One of the exceptions is the enigmatic genus Isolophodon Roth, 1903, based on very scant and fragmentary materials from Paleogene levels of central Patagonia. This taxon was ruled out from almost all taxonomic lists, although its validity has not been discussed by subsequent authors. We herein re-describe and discuss the taxonomic status of the species of Isolophodon. The type species, I. cingulosus Roth, 1903, is characterized by having lower cheek teeth with a much reduced hypoflexid, resembling derived uruguaytheriines, but lower-crowned and with three lower premolars, as in the species of Astraponotus Ameghino, 1901. This is the only astrapothere nominal species attributable to the Tinguirirican South American Land Mammal Age (SALMA, Early Oligocene). Isolophodon aplanatus Roth, 1903 (Casamayoran and Mustersan SALMAs, middle Late Eocene) has proportionally more elongated lower molars and a less developed paraflexid than the type species. Isolophodon would represent an early diverging lineage of astrapotheriids, in which some dental features evolved convergently with the more derived uruguaytheriines. Additionally, we describe other fragmentary but very significant specimens from Paleogene localities in central Patagonia (Argentina) attributable to the following taxa: cf. Scaglia kraglievichorum (Barrancan? subage), based on a partial upper molar nearly 60% larger than the type of Scaglia kraglievichorum Simpson, 1957; Astrapotheriidae gen. et sp. 1 (Barrancan? Subage, Middle Eocene), based on an isolated upper molar larger than any other Eocene astrapothere; Astrapotheriidae gen. et sp. 2, based on five isolated upper cheek teeth from “La Cantera” (Gran Barranca, Early Oligocene), characterized by a large, isolated hypocone and accessory cusps on P3-P4. These taxa enlarge the known diversity of Paleogene astrapotheres and document novel evolutionary patterns for these mammals.     

Discovery of a highly-specialized plesiadapiform primate in the early-middle Eocene of northwestern Africa

In this paper we report the first occurrence of an endemic African plesiadapiform primate from the early-middle Eocene locality of Glib Zegdou (Hammada du Dra, Algeria). Dralestes (new genus) is a very specialized taxon, and its closest known relative is the enigmatic and controversial genus Azibius from Gour Lazib (Hammada du Dra). We group both together as the Azibiidae (new rank). Dralestes provides the first evidence of the upper dentition in this group. Some critical dental characters, such as a postprotocingulum on upper teeth, consistently reveal a primate status for the azibiids. Dralestes exhibits, however, a very unusual configuration of the upper molars by the enlarged parastyle, the lack of a metaconule, and the ectoloph structure (preparacrista, centrocrista and postmetacrista are aligned in a high blade-like structure). The apparent dental specializations of both lower premolars and molars of azibiids (exaenodonty, large P(4) bearing sharp apical cusps, and M(1) having a highly elongated trigonid) point to potential relationships with Chronolestes and carpolestid plesiadapiforms. A phylogenetic analysis, performed on 55 dental characters scored for 19 primate genera, clarifies the euprimate status of Altiatlasius, and thus indicates that azibiids are the only known plesiadapiforms from Africa. Azibiids are the sister group of the clade carpolestids/Chronolestes in the superfamily Plesiadapoidea. However, the azibiids differ fundamentally from carpolestids by the combined lack of a centroconule and multiple buccal cusps on P(4). The exact position of both Chronolestes and azibiids in the plesiadapoids appears difficult to resolve. A basal position of Chronolestes in this superfamily cannot be ruled out because it exhibits a simple morphology of I(1) and no conule on P(3). Considering this ad hoc hypothesis, azibiids are found to lie outside a clade including carpolestids/plesiadapids/saxonellids, and they are the sister group to Chronolestes. The clade including the carpolestid, saxonellid, and plesiadapid families is characterized by the occurrence of a centroconule on P(3-4). The lack of this trait in Dralestes and Chronolestes could mean that azibiids are basal plesiadapoids that diverged before the evolution of the common ancestor of the three derived plesiadapoid families, i.e. at least around the Paleocene-Eocene boundary or more probably during the Paleocene. The report of the first offshoot in Africa of plesiadapoids enhances the role of Africa in the early primate radiation.