New adapiform primate fossils from the late Eocene of Egypt

Abstract

Caenopithecine adapiform primates are currently represented by two genera from the late Eocene of Egypt (Afradapis and Aframonius) and one from the middle Eocene of Switzerland (Caenopithecus). All are somewhat anthropoid-like in several aspects of their dental and gnathic morphology, and are inferred to have been highly folivorous. Here we describe a new caenopithecine genus and species, Masradapis tahai, from the ~37 million-year-old Locality BQ-2 in Egypt, that is represented by mandibular and maxillary fragments and isolated teeth. Masradapis is approximately the same size as Aframonius but differs in having a more dramatic distal increase in molar size, more complex upper molar shearing crests, and an exceptionally deep mandibular corpus. We also describe additional mandibles and part of the orbit and rostrum of Aframonius which suggest that it was probably diurnal. Phylogenetic analyses place Masradapis either as the sister taxon of Aframonius (parsimony), or as the sister taxon of Afradapis and Caenopithecus (Bayesian methods). Bayesian tip-dating analysis, when combined with Bayesian biogeographic analysis, suggests that a common ancestor of known caenopithecines dispersed to Afro-Arabia from Europe between 49.4 and 47.4 Ma, and that a trans-Tethyan back-dispersal explains Caenopithecus’ later presence in Europe.

For Masradapis: https://www.zoobank.org/urn:lsid:zoobank.org:act:41BC8459-7CCE-487F-BC59-1C34257D5C4E

For Masradapis tahai: https://www.zoobank.org/urn:lsid:zoobank.org:act:C0A620AD-6FCA-4649-A980-FCA237AFE39D     

New early Eocene anaptomorphine primate (Omomyidae) from the Washakie Basin,Wyoming, with comments on the phylogeny and paleobiology of anaptomorphines

Recent paleontological collecting in the Washakie Basin, southcentral Wyoming, has resulted in the recovery of over 100 specimens of omomyid primates from the lower Eocene Wasatch Formation. Much of what is known about anaptomorphine omomyids is based upon work in the Bighorn and Wind River Basins of Wyoming. This new sample documents greater taxonomic diversity of omomyids during the early Eocene and contributes to our understanding of the phylogeny and adaptations of some of these earliest North American primates. A new middle Wasatchian (Lysitean) anaptomorphine, Anemorhysis savagei, n. sp., is structurally intermediate between Teilhardina americana and other species of Anemorhysis and may be a sister group of other Anemorhysis and Trogolemur. Body size estimates for Anemorhysis, Tetonoides, Trogolemur, and Teilhardina americana indicate that these animals were extremely small, probably less than 50 grams. Analysis of relative shearing potential of lower molars of these taxa indicates that some were primarily insectivorous, some primarily frugivorous, and some may have been more mixed feeders. Anaptomorphines did not develop the extremes of molar specialization for frugivory or insectivory seen in extant prosimians. Incisor enlargement does not appear to be associated with specialization in either fruits or insects but may have been an adaptation for specialized grooming or food manipulation. © 1994 Wiley-Liss, Inc.     

Jemezius,a new omomyid primate from the early Eocene of northwestern New Mexico

Recently collected omomyid primate fossils from the early Eocene Regina Member, San Jose Formation, San Juan Basin, New Mexico, add significant new information to our knowledge of the family in the southern part of the Rocky Mountain region during Wasatchian time. A total of seven specimens represent at least two omomyid species on the basis of size alone, but only the larger of these species, here described as Jemezius szalayi, gen. et sp. nov., is currently known from sufficient material to permit an adequate taxonomic assignment. Jemezius possesses several traits in common with Uintanius that clearly reflect a close phylogenetic relationship between these genera, but lacks the specialized premolar hypertrophy characteristic of that genus. The presence of uintaniinin omomyids in New Mexico during the middle Wasatchian, well before their first appearance in Wyoming during Bridgerian time, supports the hypothesis that several of the exotic mammals that first appear in Wyoming near the Wasatchian-Bridgerian boundary may be immigrant taxa from the south.     

New material of Diacodexis (Mammalia,Artiodactyla) from the early Eocene of Southern Europe

Diacodexeidae are the first representatives of Artiodactyla in the fossil record. Their first occurrence is at the very base of the Ypresian (earliest Eocene, 56.0 Ma) with Diacodexis, a genus well diversified during the early Eocene in Europe, especially during the MP7–MP8 + 9 interval. However, most of European species are documented by scarce material, retrieved from single localities. In this work, we describe new Diacodexis material from ～MP7 and ～MP8 + 9 localities of Southern Europe, including material of D. antunesi from Silveirinha, considered as the most primitive European Diacodexis species, and material from three localities from Southern France (Fordones, Palette, and La Borie). The new material documents Diacodexis premolar morphology and deciduous dentition which bear potentially important phylogenetic information, as well as astragali, including a specimen from Silveirinha that constitutes the earliest occurrence of an astragalus of the genus Diacodexis in the European fossil record. Investigation of the enamel microstructure reveals that early European species had a simple enamel pattern with one-layered Schmelzmuster composed of ‘basic’ radial enamel only, instead of the two-layered Schmelzmuster (thin radial enamel + thick layer of Hunter-Schreger bands) observed on North American species and so far considered to represent the primitive condition within Artiodactyla. In accordance with previous studies, our observations highlight that Diacodexis gigasei from Belgium is morphologically closer to the North American species D. ilicis than to D. antunesi from Portugal. The latter species, together with D. aff. antunesi from Fordones, appears to be morphologically closer to the Asiatic taxa D. indicus and D. pakistanensis. Finally, we found numerous similarities between D. cf. gigasei from Palette and D. gigasei, a result that challenges the intra-European provincialism that characterizes the earliest Ypresian. Diacodexis gigasei could be one of the rare species shared by the northwestern and southwestern European bioprovinces.     

New primate hind limb elements from the middle Eocene of China

The continued washing, sorting, and identification of middle Eocene (45 Mya) primates from the Shanghuang fissure-fillings (Jiangsu Province, China) have produced additional hind limb elements. All are isolated elements. The strepsirhine hind limb elements include a first metatarsal and a talus, which are appropriate in size and morphology to pertain to Adapoides troglodytes. Adapoides is interpreted as a quadrupedal-climbing (nonleaping) primate with similarities to living lorises and the fossil primate Adapis. The haplorhine hind limb elements are estimated to span a range of adult body sizes from tiny (17 g) to small (200 g). Included among the new sample of haplorhine hind limb specimens is the smallest primate talus reported thus far. These new postcranial specimens expand our understanding of early haplorhine hind limb anatomy and demonstrate additional similarities between Shanghuang eosimiids and other anthropoids.     

New proviverrines (Hyaenodontida) from the early Eocene of Europe; phylogeny and ecological evolution of the Proviverrinae

We describe six proviverrine species from the Early Eocene of France. Three species are new: M inimovellentodon russelli sp. nov. from Mutigny [mammal palaeogene (MP)8 + 9], B oritia duffaudi sp. nov. from La Borie (MP8 + 9), and L eonhardtina godinoti sp. nov. from Grauves (MP10). We describe new specimens and propose new generic combinations for three species from MP10: Protoproviverra palaeonictides, Matthodon menui, and Oxyaenoides lindgreni. We also propose a new generic combination for the primitive Eoproviverra eisenmanni (MP7). Matthodon menui was previously considered as a possible oxyaenodontan, but the new fossils clearly support its reference to Hyaenodontida. Leonhardtina godinoti and Ma. menui are the oldest occurrences for these genera, which were previously unknown before the Middle Eocene. Moreover, the discovery of the proviverrine Mi. russelli in Mutigny implies that the Proviverrinae dispersed in Northern Europe between biozone Palaeocene‐Eocene (PE) III (Abbey Wood) and biozone PE IV (Mutigny). This also supports a homogenization of the European faunas during the Early Eocene. The dispersal is concomitant with the disappearance of the oxyaenodontans, arfiines, and sinopines (Hyaenodontida) from Europe. The proviverrines may have filled the ecological niches left vacant by the disappearance of the other carnivorous mammals. With 20 genera and over 30 species, proviverrines were successful in Europe. We performed the first phylogenetic analysis comprising almost all the Proviverrinae. Our analyses indicate that the Proviverrinae diversified greatly during the Early Eocene Climatic Optimum and show a general trend towards specialization throughout the Eocene. © 2014 The Linnean Society of London     

Zhailimeryx, A New Lophiomerycid Artiodactyl (Mammalia) from the Late Middle Eocene of Central China and the Early Evolution of Ruminants

A new genus and species of primitive selenodont artiodactyl, Zhailimeryx jingweni, occurs in the late middle Eocene Zhaili Member of the Heti Formation, Yuanqu Basin, Shanxi Province, China. A phylogenetic analysis of dental characters suggests that Zhailimeryx is closely related to Lophiomeryx and other lophiomerycid ruminants of Asia and Europe. Zhailimeryx and other Eocene records of Lophiomerycidae from Asia support an Asian origin for this family, followed by dispersal into Europe both before and after the Grande Coupure. Morphological evidence from Zhailimeryx suggests that ruminant artiodactyls had already undergone substantial diversification prior to the late middle Eocene, and it reopens the issue of whether the higher taxa Tragulina and Pecora are valid expressions of ruminant phylogeny.     

A new genus and species of an early Eocene primate from North Africa

A new Adapiform Primate from the locality of Chambi (Tunisia) is described and assigned toDjebelemur martinezi gen.nov., sp. nov. Holotype CBI 33, fragment of left mandible with P/3-M/3. Other material includes a lower and two upper isolated molars and one probable lower canine. This new material is assigned to the Adapidae.     

New specimens of the mesonychid Dissacus praenuntius from the early Eocene of Wyoming and evaluation of body size through the PETM in North America

The Mesonychia is a group of archaic carnivorous mammals of uncertain phylogenetic affinities with a Holarctic distribution during the Paleogene. Intensive fossil collecting efforts in the Bighorn Basin, Wyoming, have resulted in recovery of the largest sample and most complete specimens yet known of the mesonychid Dissacus praenuntius from the second biozone of the Wasatchian North American Land Mammal Age (Wa-0). The Wa-0 biozone corresponds to the body of the Paleocene-Eocene Thermal Maximum (PETM), a brief but intense global warming event that occurred ~56 myr ago that significantly impacted terrestrial mammal faunas, including dwarfing in many mammal lineages. To evaluate the potential response of this lineage to climate change, we compared the PETM sample of D. praenuntius with those recovered from just before the PETM in the last biozone of the Clarkforkian North American Land Mammal Age (Cf-3) and just after the PETM in the Wa-1 biozone. While the sample size is still too small to say with certainty, tooth size (as a proxy for body weight) of D. praenuntius appears to be smaller during the late PETM than during either the pre-PETM Cf-3, or post-PETM Wa-1 biozones, suggesting the possibility of a muted dwarfing response to the PETM. However, the pattern observed for D. praenuntius differs from that of many other PETM mammals, as the shift to smaller body size is less pronounced and may have only occurred in late Wa-0.     

New notharctine (primates,adapiformes) skull from the Uintan (middle Eocene) of San Diego County,California

A new genus and species of notharctine primate, Hesperolemur actius, is described from Uintan (middle Eocene) aged rocks of San Diego County, California. Hesperolemur differs from all previously described adapiforms in having the anterior third of the ectotympanic anulus fused to the internal lateral wall of the auditory bulla. In this feature Hesperolemur superficially resembles extant cheirogaleids. Hesperolemur also differs from previously known adapiforms in lacking bony canals that transmit the internal carotid artery through the tympanic cavity. Hesperolemur, like the later occurring North American cercamoniine Mahgarita stevensi, appears to have lacked a stapedial artery. Evidence from newly discovered skulls of Notharctus and Smilodectes, along with Hesperolemur, Mahgarita, and Adapis, indicates that the tympanic arterial circulatory pattern of these adapiforms is characterized by stapedial arteries that are smaller than promontory arteries, a feature shared with extant tarsiers and anthropoids and one of the characteristics often used to support the existence of a haplorhine-strepsirhine dichotomy among extant primates. The existence of such a dichotomy among Eocene primates is not supported by any compelling evidence. Hesperolemur is the latest occurring notharctine primate known from North America and is the only notharctine represented among a relatively diverse primate fauna from southern California. The coastal lowlands of southern California presumably served as a refuge area for primates during the middle and later Eocene as climates deteriorated in the continental interior. Hesperolemur probably was an immigrant taxon that entered California from either the northern (Wyoming/Utah) or southern (New Mexico) western interior during the middle Eocene © 1995 Wiley-Liss, Inc.     

The skeleton of early Eocene Cantius, oldest lemuriform primate

A recently discovered partial skeleton of the adapid Cantius trigonodus from the early Eocene Willwood Formation of the Bighorn Basin, Wyoming, documents substantial new information about the anatomy of the oldest lemuriform primates. It is very similar in all features to its descendant, middle Eocene Notharctus, and both exhibit numerous resemblances to certain extant Malagasy lemurs, particularly Lepilemur, Propithecus, Lemur, and Hapalemur griseus. Like these forms, Cantius had relatively long hind limbs and short forelimbs. Forelimb traits (prominent brachialis flange of the humerus, well-developed olecranon process of the ulna, and strong shafts of the ulna and radius) suggest active use of the forelimbs in progression. Specializations in the hind limb (e.g., expanded articular surface of the femoral head, narrow and elevated patellar trochlea and prominent lateral trochlear ridge, posteriorly oriented femoral and tibial condyles, narrow and elongate talus, and hallucal metatarsal with prominent peroneal tubercle) indicate capabilities for leaping and for powerful grasping with an opposable hallux. Cantius was presumably primitive in having a relatively long ischium and much more distal inferior tibial tuberosity than most extant lemurs--traits suggesting that powerful extension of the thigh and flexion at the knee were important in its locomotion and posture. We interpret Cantius as an active arboreal quadruped with a propensity for leaping. The existence of this skeletal structure in one of the oldest primates of modern aspect suggests that it represents the primitive lemuriform morphology.     

First discovery of colobine fossils from the early to middle Pleistocene of southern Taiwan

Here we report on two kinds of cercopithecid fossil monkeys (Cercopithecinae and Colobinae) from the early to middle Pleistocene sediments of the Chochen (=Tsochen) area (Tsailiao-chi or Shinhua Hill), southern Taiwan. The fossil specimens include the first fossil record of colobine monkeys from Taiwan, where only macaque monkeys now occur. All cercopithecine fossils were identified as Macaca cf. Macaca cyclopis, the extant Taiwan macaque, except for one extremely large isolated upper molar, which may belong to another macaque species. On the other hand, all colobine specimens fall within the size variation of extant and extinct Rhinopithecus, but its specific status cannot be determined because of the scantiness of the fossil material. In Taiwan, Rhinopithecus presumably became extinct in the late Pleistocene, probably owing to global cooling and vegetation change, whereas macaques, which are of almost the same body size as Rhinopithecus, survived as M. cyclopis to the present. The contrasting history of survival between the two kinds of monkeys may be due to ecological/behavioral differences between them or as a result of accidental events that occurred in the Pleistocene of Taiwan.     

New fossils from China elucidating the phylogeny of Praesiricidae (Insecta: Hymenoptera)

A new subfamily of Praesiricidae (Pamphilioidea), Decorisiricinae subfam.n. , is erected based on three new genera: Decorisiricius gen.n. , Limbisiricius gen.n. and Brevisiricius gen.n. Two new species – Decorisiricius patulus gen. et sp.n. and D. longus sp.n. – from the Lower Cretaceous Yixian Formation and three species –Limbisiricius aequalis gen. et sp.n. , Limbisiricius complanatus sp.n. and Brevisiricius partialis gen. et sp.n. – from the Middle Jurassic Jiulongshan Formation, are described. Based on these well‐preserved new fossil specimens and previously published data, the nonmonophyly of Praesiricidae is confirmed and the phylogenetic relationships of species of Praesiricidae are analysed for the first time. Two main clades within Praesiricidae are recognized from the cladistic analysis: Decorisiricinae subfam.n. forms a monophyletic lineage, with the remaining members of Praesiricidae plus Megalodontes (Megalodontesidae) forming its sister group. The two subfamilies Archoxyelydinae and Praesiricinae are discarded with no strong supported synapomorphic characters based on phylogenetic research. A key to all genera of Praesiricidae is provided. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:38D703ED‐127A‐4DB0‐8153‐8D78AF4AC212 .     

New materials of Cisuralian (early Permian) radiolarians from western Cambodia: Paleobiogeographic implications in the Paleotethys

Radiolarians, including the new species Entactinia pailinensis Ito n. sp., were obtained from the Pailin area, western Cambodia. The radiolarians indicated an age around the Asselian–Sakmarian of the Cisuralian (early Permian). The new species is characterized by an evenly-sized-porous exosphere composed of a polygonal outer porous plate and circular inner porous plate with some radial outer spines. A previous study concluded that Entactinia Foreman rapidly expanded in the early–middle Cisuralian. Our discovery of this new species adds further occurrence data of Entactinia in the early–middle Cisuralian. In addition, another previous study highlighted the uneven distribution of Pseudotormentus De Wever and Caridroit compared with the wider distribution of Quadriremis Nazarov and Ormiston through the Permian, in particular the Guadalupian (middle Permian). Our results combined with those of previous studies indicate that the uneven distribution might extend back to the Sakmarian of the Cisuralian at least.     

New strepsirrhine primate from the late Eocene of Peninsular Thailand (Krabi Basin)

In this paper, we describe the newly discovered lower jaw of a primate from the late Eocene Krabi coal mine (Bang Mark pit) of Peninsular Thailand. We performed microtomographic examinations at the European Synchrotron Radiation Facility (ESRF, Grenoble, France) to analyze different morphological aspects of the jaw and teeth. Although partially preserved, this fossil mandible reveals a set of distinctive dental traits (e.g., double-rooted P(2) and molarized P(4)) that allow us to describe a new stepsirrhine adapiform: Muangthanhinius siami, new genus and species. This taxon is somewhat atypical among Paleogene adapiforms, and more specialized than the sivaladapid adapiforms (hoanghoniines) that existed in Asia in the same epoch. In fact, Muangthanhinius shows a degree of dental specialization approximating that of some modern strepsirrhine lemuriforms, although it lacks the highly specialized anterior dentition characterizing this living primate group (canine + incisors forming a very procumbent toothcomb). In contrast, Muangthanhinius exhibits a large canine deeply anchored within the dentary that probably protruded high above the toothrow. Finally, despite the development of a molarized P(4) as in Miocene sivaladapid sivaladapines, Muangthanhinius differs in molar morphology from this group, and the position of this new taxon within the Adapiformes remains indeterminate. Clarification of its phylogenetic position will require more morphological evidence than is currently available.     

New acrodont lizards (Lacertilia) from the Middle Eocene of southern Mongolia

The problematic lizard family Changjiangosauridae, representatives of which inhabited Asia in the Early Paleogene, is discussed. Six new species of this group, including Acrodontopsis robustus gen. et sp. nov., Agamimus gracilis gen. et sp. nov., Graminisaurus interruptus gen. et sp. nov., Khaichinsaurus reshetovi gen. et sp. nov., Lavatisaurus elegans gen. et sp. nov., and Lentisaurus giganteus gen. et sp. nov., from the Middle Eocene of the Khaichin Uul 2 locality (southern Gobi, Mongolia) are described. It is shown that Changjiangosauridae are probably related to the Late Cretaceous Isodontosauridae and recent Uromastycidae; independent development of a number of dental features in different lineages of Acrodonta (Iguania) is corroborated.     

Fish otoliths from the Priabonian (Late Eocene) of North Italy and South-East France - Their paleobiogeographical significance

The study of the Late Eocene (Priabonian) otolith associations from Possagno, North-East Italy, and from the Synclinal d’Allons in Haute Provence, South-East France, allows for the reconstruction of a teleost fauna of 55 taxa, which is the most diversified assemblage presently known from the Upper Eocene Paleo-Mediterranean basin. Thirty-six taxa are identified at the species level, and five of those are new: “genus Alepocephalidarum” astrictus, “genus Lophiiformorum” canovae, “genus Agonidarum” sudans, “genus Uranoscopidarum” cochlearis and Aseraggodes laganum. In the Synclinal d’Allons, the otolith associations reflect a tropical to subtropical neritic environment with a few mesopelagic fishes. At Possagno, the associations indicate an environment that changed from one that was deep and exposed to the pelagic realm and then evolved to a more shallow sea with a well-diversified benthic life and less mesopelagic fishes. A paleobiogeographical analysis of all known data on Priabonian otoliths, worldwide, shows clearly a western Atlantic (Louisiana) and an eastern Atlantic-Paleomediterranean association. In the eastern Atlantic-Paleomediterranean association, the Aquitaine association not only differs from the Possagno-Allons association in function of its more distant geographical position, but also by its stronger oceanic character in the southern part of the basin, and by the occurrence in the north, of a very shallow water facies (Saint-Estephe Formation) that contains some taxa which are known nowhere else in the Priabonian. The Ukraine fauna is characterized by a high number of species, which have an Oligocene record in other European sites. The northern geographic location of Ukraine, combined with the good connections to both the North Sea Basin and the Turgai street can provide the explanation. Many Oligocene species (or their close relatives) probably already existed at Eocene times in more northern regions, but could penetrate only in more southern European seas since the strong cooling at the beginning of the Oligocene.