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1.
The colugos, or flying lemurs (Dermoptera), are arboreal gliding mammals that are commonly grouped with tree‐shrews (Scandentia) and Primates in the superorder Euarchonta. However, little is known about the head and neck muscles of these gliding mammals. This raises difficulties for the discussion of not only the functional morphology and evolution of colugos, but also the origin, evolution, functional morphology, and phylogenetic relationships of the Euarchonta as a whole, and thus also of our own clade, the Primates. In this work, I describe the head and neck muscles of the colugo Cynocephalus volans, and compare these muscles with those of other mammals, either dissected by me or described in the literature. My observations and comparisons indicate that, with respect to the number of muscles, the plesiomorphic condition for euarchontans as well as for primates is more similar to that found in extant tree‐shrews than in extant colugos. This is because various muscles that were probably plesiomorphically present in the euarchontan and primate clades, as, e.g., the stylohyoideus, mandibulo‐auricularis, cleido‐occipitalis, omohyoideus, and sternohyoideus, are not present as independent elements in extant colugos. These observations and comparisons also indicate that various laryngeal and facial muscles that are present in modern humans were absent in the last common ancestor of extant primates. J. Morphol., 2009. © 2008 Wiley‐Liss, Inc.  相似文献   

2.
A comparative morphometric analysis of isolated proximal and intermediate phalanges attributed to the paromomyids Ignacius graybullianus and Phenacolemur simonsi was undertaken to test the hypothesis that these fossil phalanges exhibit evidence of a dermopteran-like interdigital patagium. Linear dimensions were collected for the fossil phalanges and a comparative sample of associated proximal and intermediate phalanges representing extant tree squirrels, tree shrews, dermopterans (colugos), gliding rodents and marsupials, and prosimian primates. Quantitative data indicate that the proximal and intermediate phalanges of paromomyids are most similar in their overall shape to those of the dermopteran Cynocephalus. The proximal phalanges of paromomyids and colugos possess well-developed flexor sheath ridges and broad, high shafts, whereas the intermediate phalanges of these taxa are most similar to one another in their trochlear morphology. Discriminant analysis indicates that all of the paromomyid intermediate phalanges resemble those from colugo toes more so than those from colugo fingers. Moreover, the relative length and midshaft proportions of both the proximal and intermediate phalanges of paromomyids closely resemble those of several squirrels that lack an interdigital patagium. The following conclusions are drawn from this study: 1) paromomyids share a number of derived phalangeal features with modern dermopterans that may be indicative of a phylogenetic relationship between them, 2) existing intermediate phalanges of paromomyids are inconsistent with the “mitten gliding” hypothesis because they do not possess the distinctive length and midshaft proportions characteristic of colugo manual intermediate phalanges, and 3) paromomyids share with colugos and the scaly-tailed squirrel Anomalurus several aspects of phalangeal morphology functionally related to frequent vertical clinging and climbing on large-diameter arboreal supports. Am J Phys Anthropol 109:397–413, 1999. © 1999 Wiley-Liss, Inc.  相似文献   

3.
The morphological evidence for the phylogenetic relationships of euprimates, archaic primates, and related eutherian orders is reviewed following the methods of Hennigian phylogenetic systematics. Euprimates, the group including living primates and their closest common ancestor, is diagnosed by a suite of shared derived characters of the cranium and posteranium exhibiting relatively unique distributions among Eutheria. Plesiadapiformes, the group of archaic primates generally held to be the sister group to Euprimates, is not demonstrably monophyletic (with or without Microsyopidae). The Superorder Archonta (primates, tree shrews, bats, and colugos) is the only higher-level grouping including Euprimates that is based on uniquely derived morphological characters. Hypotheses of relationships within Archonta ally Euprimates with either tree shrews or some plesiadapiforms (paromomyids and plesiadapids), but the eurprimate-tree shrew clade receives more support from the distribution of derived characters among the taxa studied. Because the higher-level affinities of Euprimates are not well resolved, we advocate equating the Order Primates with the taxon Euprimates.  相似文献   

4.
The complete mitochondrial genome was obtained from a microchiropteran bat, Artibeus jamaicensis. The presumptive amino acid sequence for the protein-coding genes was compared with predicted amino acid sequences from several representatives of other mammalian orders. Data were analyzed using maximum parsimony, maximum likelihood, and neighbor joining. All analyses placed bats as the sister group of carnivores, perissodactyls, artiodactyls, and cetaceans (e.g., 100% bootstrap value with both maximum parsimony and neighbor joining). The data strongly support a new hypothesis about the origin of bats, specifically a bat/ferungulate grouping. None of the analyses supported the superorder Archonta (bats, flying lemurs, primates, and tree shrews). Our hypothesis regarding the relationship of bats to other eutherian mammals is concordant with previous molecular studies and contrasts with hypotheses based solely on morphological criteria and an incomplete fossil record. The A. jamaicensis mitochondrial DNA control region has a complex pattern of tandem repeats that differs from previously reported chiropteran control regions. Received: 22 January 1998 / Accepted: 3 June 1998  相似文献   

5.
Astragali and calcanea from the English late Eocene, attributed to the extinct 'insectivoran' family Nyctitheriidae, are described for the first time. They contrast with those of the strict sense insectivorans, the Lipotyphla, in which order nyctitheres have usually been placed, and compare more closely with those of Scandentia (tree shrews) and the extinct Plesiadapiformes. Functional analysis demonstrates that inversion of the foot was possible between the astragalus and calcaneum of nyctitheres, allowing them to be interpreted as having had a tree-dwelling, probably scansorial, mode of life. These tarsal bones are compared with those of other placental mammals. Cladistic analysis of tarsal characters places nyctitheres as sister group to the Plesiadapiformes within the superorder Archonta, excluding Chiroptera (bats). An independent analysis of dental characters places them as sister group to the rest of the Archonta, but still excluding bats. Combining the dental and tarsal characters places nyctitheres as sister group to Plesiadapiformes and all modern groups of archontans except bats. A new osteological synapomorphy is proposed for the Archonta, which is thus considered to comprise Chiroptera, Deccanolestes , Nyctitheriidae, Plesiadapiformes, Dermoptera (including Mixodectidae), Scandentia and Primates. Insectivorans s.l . have long been at the centre of arguments on placental origins, although lipotyphlans are usually regarded as a monophyletic group, rather than paraphyletic stem placentals. Reidentification of an extinct lipotyphlan family as having archontan relationships raises the possibility of advances in other areas of insectivoran phylogeny when more postcranial elements become known. The early Oligocene extinction of nyctitheres may be causally related to the rise of insectivorous microchiropteran bats, which, because of their flying ability, would have been able to forage more widely.  相似文献   

6.
The hindlimbs allow bats to attach to the mother from birth, and roost during independent life. Despite the great morphological diversity in Chiroptera, the hindlimbs morphology and its postnatal development have been poorly studied. Postnatal development of hindlimbs in Noctilio leporinus is described, further comparing the morphology of adults with that of Noctilio albiventris and previously reported species (Desmodus rotundus, Artibeus lituratus, Molossus molossus). The ossification ending sequence at autopodium elements of N. leporinus does not follow the distal to proximal directional sequence described for D. rotundus, exhibiting a heterochronic delayed ossification ending for the digits of N. leporinus regarding other hindlimb elements, associated with the bigger relative autopodium size of this fisher bat regarding other bat species. Noctilionid bats share the same adult hindlimb bone morphology, except for differences at hindlimb proportions and calcar ossification degree. There are differences in the number and position of bony processes, slots and sesamoids of adult noctilionid fisher bats regarding previously reported species; most differences are concentrated at the autopodium and are related to an increased surface for muscular insertion and the structural support of claws. These facts seem to be closely associated with functional demands of the feeding strategy of noctilionid fisher bats.  相似文献   

7.
Hipposideros commersoni is a large microchiropteran bat endemic to Madagascar. We analysed fragments of its prey from faeces and from underneath feeding perches to describe its diet from four sites. Diet was similar across sites and Coleoptera was the main prey item by percentage volume (75%), followed by Hemiptera (13%). Carabidae and Scarabidae were the most frequent coleopterans found in the diet. Direct observations (n = 3) were made of bats flying short distances from perches along forest trails to prey on Cicadidae ( c. 20 mm in length) located on tree trunks. There were differences in the composition of faecal samples collected form netted bats and pellets collected under feeding perches, with the latter consisting of more Blattoptera (Blattellidae 'cockroaches'). Hipposideros commersoni appears to have a unique foraging behaviour and diet among Malagasy microchiropterans and its preference for certain Coleoptera and other large invertebrates may account for reported seasonal variation in body fattening and activity.  相似文献   

8.
Most researchers have considered the calcar to be a unique and homologous structure within Chiroptera (e.g., the presence of this structure and its associated musculature has been cited as a synapomorphy supporting bat monophyly). However, we report that significant morphological variation exists between Microchiroptera and Megachiroptera. In microchiropterans, a calcified or cartilaginous element articulates directly with the calcaneal tuberosity of the ankle and projects into the uropatagium. In megachiropterans, a cartilaginous structure projects from the tendon of the gastrocnemius muscle into the uropatagium and has no articulation with the calcaneal tuberosity. Considerable variation also exists in the musculature associated with these structures. Phylogenetic interpretation of hindlimb morphology of extant and fossil taxa indicates that the calcar may not be homologous in all bats. We suggest retention of the term calcar for the microchiropteran structure and propose a new term, uropatagial spur, for the megachiropteran structure. The fossil bat Archaeopteropus transiens (Oligocene) has long been presumed to be a megachiropteran; however, this form has a microchiropteran-type calcar. Reconsideration of morphological evidence from this and previous studies indicates that Archaeopteropus is not a megachiropteran but, rather, a basal member of the microchiropteran lineage.  相似文献   

9.
Ontogenetic investigations confirm that independent entotympanics are absent in living primates. Although cartilage occurs in the petrosal tympanic processes of some primates, the assumption that a suppressed entotympanic is thereby indicated can be adequately refuted according to embryological canons of interpretation. Problems regarding the homologies of different entotympanics, largely ignored by paleontologists and systematists, reduce or negate their taxonomic valency for all but closely related groups. Until such puzzles are resolved, the possible but doubtful existence of entotympanics in plesiadapoids and inferred pre-primate ancestors cannot buttress claims for alleged ties between primates and certain entotympanic-bearing eutherians (principally bats, colugos and tree shrews).  相似文献   

10.
Paleontological and molecular evidence have been employed to suggest that flying lemurs (Dermoptera) and primates form a monophyletic group, in sharp contrast with cranial and postcranial evidence indicating sister group relationships between flying lemurs and bats (Chiroptera). New evidence from the epidermis of the volar pads of primates, tree shrews, flying lemurs, bats, and other mammals was examined and mapped on to various hypotheses of archontan relationships. The micro-anatomy of the skin on the palm and sole of flying lemurs and bats differs fundamentally from that of tree shrews (Scandentia) and primates. The volar skin of flying lemurs and bats lacks the serial arrangement of papillary ridges and grooves ("fingerprints") found in primates, tree shrews, and many other mammals. Moreover, the junction between the epidermis and dermis in flying lemurs and bats is relatively flat and shows little or no development of the internal ridges that occur in primates and tree shrews. When mapped on to a set of cladograms of mammals currently allocated to the superorder Archonta, this new evidence does not support sister group relationships between flying lemurs and primates, regardless of the volar skin morphology that characterized the last common ancestor of Archonta. Micro-anatomical differences that distinguish the volar skin of flying lemurs and bats from that of primates and tree shrews reflect a profound dichotomy in the functional roles fulfilled by the extremities, which could be significant in a phylogenetic context.  相似文献   

11.
We describe the bony labyrinth morphology of the Eocene ‘archaic ungulate’ Hyopsoduslepidus (Bridgerian, North America) reconstructed from micro computed tomography scan data. Comparisons with the inner ear of the Eocene early diverging artiodactyl Diacodexis and perissodactyl Xenicohippus allow refining the picture of the ancestral inner ear morphology of Euungulates. These taxa are very close morphologically and mostly differ by slight differences in their semicircular canal angulations and profile. They all present a secondary crus and a low position of the plane of the lateral semicircular canal relative to the posterior semicircular canal. These two characters, considered as ancestral features for Theria, might be symplesiomorphies of Euungulata as well. Hyopsodus and Xenicohippus share characters also observed in other basal Equoidea, which would support the close relationship between these two taxa previously proposed in the literature. A functional study of the cochlea of Hyopsodus lepidus is also realised to discuss its putative ability of using terrestrial echolocation previously proposed in the literature. The morphology of the cochlea of Hyopsodus lepidus does not indicate a specialisation to sophisticated echolocation such as observed today in microchiropteran bats. However, its estimated audible range of frequencies (208 Hz to 76.8 KHz) would be compatible with terrestrial echolocation.  相似文献   

12.
Current phylogenics of mosasauroid reptiles are reviewed and a new phylogeny examining aigialosaur interrelationships presented. Patterns of mesopodial ossification and overall limb morphology are described for adult mosasauroids. Ossification sequences are mapped onto a phylogeny in order to assess the distribution of ontogenetic characters. Consistent and ordered distributions are found. Based on the phylogenetic distribution of ossification patterns, an overall mesopodial ossification sequence for mosasaurs is proposed. Carpal sequence: ulnare—distal carpal four (dc4)—intermedium—dc3—radiale or dc2—de1 or pisiform and dc5. Tarsal sequence: astragalus—distal tarsal four or calcaneum. Skeletal paedomorphosis is recognized as a dominant pattern in the evolution of mosasauroid limbs. Apomorphic characters of skeletal paedomorphosis, apparent in most taxa, reach extremes in tylosaurs. Arguments for the presence of a single proximal cartilage in the tarsus of mosasaurs are made. This cartilage is presumed to include ossification centres from which both the astragalus and calcaneum will ossify.  相似文献   

13.
We conducted a series of parallel DNA-hybridization experiments on a small group of bats (species of Pteropus, Rhinolophus, Noctilio and Pteronotus) and outgroups (Lemur, Cynocephalus, Didelphis), using whole-genome labels and tracers made from extracts enriched with AT and two levels of GC content. FITCH (additive phylogenetic trees) topologies were constructed from the four sets of comparisons, indexed as both delta Tmode and delta NPHs (normalized percentage of hybridization). Based on our previous work showing that the shared AT bias of pteropodids and some microchiropterans may affect the rank-ordering of taxa based on either AT- or GC-rich labels, our expectation was that the resulting trees would show differing topologies when generated from tracers made with the variously enriched DNA extracts. Whereas there was some variation among the trees, most of them grouped the bats together, and almost all paired the representative megachiropteran and rhinolophoid microchiropteran as sister-taxa in contrast to the other microchiropterans. As the pteropodid-rhinolophoid relationship is an unexpected and unlikely one, we attribute this association to an AT bias that was not obviated even by our most GC-rich labels, and suggest that such a bias may compromise the truth of some molecular trees. Accordingly, we believe the broader issue of bat monophyly remains unresolved by DNA-hybridization and probably also by gene-sequencing studies.  相似文献   

14.
A nearly complete cranium of Ignacius graybullianus provides increased understanding of the cranial anatomy of Plesiadapiformes. In nearly all details of cranial anatomy, Ignacius differs markedly from primates. USNM 421608 exhibits a long tapering snout, small widely spaced orbits, and a complete lack of postorbital process or bar. Large olfactory bulbs are inferred from the wide interorbital space. The marked flare of the zygomatic arches suggests that Ignacius possessed large and powerful temporal muscles. The basicranial region is particularly well preserved and reveals a distinct suture between the petrosal bone and an entotympanic bulla. This suture is visible on both the left and right sides of the skull and dispels the hypothesis that Ignacius and, by inference, other Plesiadapiformes share the primate synapomorphy of a petrosal bulla. To test the phylogenetic position of Ignacius, cranial characters were identified and scored for Ignacius, Plesiadapis, Cynocephalus, and a number of primates, bats, and scandentians. Two erinaceomorph insectivores were also included to allow the assessment of archontan monophyly. These characters were incorporated into a maximum-parsimony analysis to determine the phylogenetic position of Plesiadapiformes. There are several important phylogenetic conclusions that can be inferred from this analysis: 1) Ignacius and Plesiadapis make up a monophyletic clade; 2) Plesiadapiformes may be the sister group of Dermoptera; 3) Scandentia, not Plesiadapiformes, is the sister group of Primates; and 4) Primates, plesiadapiforms, bats, colugos, and scandentians may not form a monophyletic clade Archonta. Consequently, the taxon Archonta is in need of review. © 1992 Wiley-Liss, Inc.  相似文献   

15.
Large animalivorous bats include carnivorous, piscivorous and insectivorous microchiropterans. Skull proportions and tooth morphology are examined and interpreted functionally. Four wide- faced bats from four families are convergent in having wide skulls, large masseter muscle volumes and stout jaws, indicating a powerful bite. Three of the four also have long canine teeth relative to their maxillary toothrows. Carnivorous bats have more elongate skulls, larger brain volumes and larger pinnae. The wide-faced bats are all dral emitters and have heads positively tilted relative to the basicranial axis. The carnivorous species are nasal-emitting bats and have negatively tilted heads. The orientation of the head relative to the basicranial axis affects several characters of the skull and jaws and is not correlated with size. The speculation that the type of echolocation may be more of a determinant of evolutionary change than the feeding mechanism is addressed. Wide-faced bats are thought to be capable of eating hard prey items (durophagus) and are probably non- discriminating, aurally less sophisticated insect generalists while the carnivorous and non- durophagus insectivorous bats may be more discriminating and aurally more sophisticated in what they eat.  相似文献   

16.
Patterns of growth and variation of the appendicular skeleton were examined in Thorius, a speciose genus of minute terrestrial plethodontid salamanders from southern Mexico. Observations were based primarily on ontogenetic series of each of five species that collectively span the range of adult body size in the genus; samples of adults of each of seven additional species provided supplemental estimates of the full range of variation of limb skeletal morphology. Limbs are generally reduced, i.e., pedomorphic, in both overall size and development, and they are characterized by a pattern of extreme variation in the composition of the limb skeleton, especially mesopodial elements, both within and between species. Fifteen different combinations of fused carpal or tarsal elements are variably present in the genus, producing at least 18 different overall carpal or tarsal arrangements, many of which occur in no other plethodontid genus. As many as four carpal or tarsal arrangements were observed in single population samples of each of several; five tarsal arrangements were observed in one population of T. minutissimus. Left-right asymmetry of mesopodial arrangement in a given specimen is also common. In contrast, several unique, nonpedomorphic features of the limb skeleton, including ossification of the typically cartilaginous adult mesopodial elements and ontogenetic increase in the degree of ossification of long bones, are characteristic of all species and distinguish Thorius from most related genera. They form part of a mechanism of determinate skeletal growth that restricts skeletal growth after sexual maturity. Interspecific differences in the timing of the processes of appendicular skeletal maturation relative to body size are well correlated with interspecific differences in mean adult size and size at sexual maturity, suggesting that shifts in the timing of skeletal maturation provide a mechanism of achieving adult size differentiation among species. Processes of skeletal maturation that confer determinate skeletal growth in Thorius are analogous to those typical of most amniotes – both groups exhibit ontogenetic reduction and eventual disappearance of the complex of stratified layers of proliferating and maturing cartilage in long bone epiphyses – but, unlike most amniotes, Thorius lacks secondary ossification centers. Thus, the presence of secondary ossification centers cannot be used as a criterion for establishing determinate skeletal growth in all vertebrates.  相似文献   

17.
Fifteen species of neotropical and three species of paleotropical bats are known either to roost in or to make tents in over 80 species of vascular plants. We summarize the current knowledge of bat-tent architecture, report two new styles of tents (conical and apical) from the Paleotropics, compare the similarity in tents constructed, or used, by neotropical and paleotropical bats, and consider possible functions of tents. Seven styles of tents are known from the Neotropics, three (conical, palmate umbrella, and apical tents) are known from both the Neo- and the Paleotropics, and one (stem tent) is unique to the Paleotropics. In the Neotropics tent-roosting and/or tent-making appears to be a behavior unique to the diverse microchiropteran family Phyllostomidae (subfamily Phyllostomatinae: tribe Stenodermatini), and in the Paleotropics two members of the megachiropteran family Pteropodidae and one member of the microchiropteran family Vespertilionidae are known to construct or roost in tents. Despite the variety of plant taxa used by bats in tent construction, there appears to be a limited number of different leaf forms that can be altered by bats and used as tents. We suggest that the similarity in tent architecture observed among the neotropical and paleotropical bats is a consequence of convergence in leaf morphology among forest understory plants. The congruence in tent-making/roosting behavior observed in members of the Stenodermatini and the Pteropodidae (genusCynopterus) suggests a phylogenetic influence on these behaviors. The similarity in tent-making and/or tent-roosting behavior and life-history traits (small, <70 g, mostly foliage-roosting frugivores) among these divergent neotropical and paleotropical taxa supports a convergence hypothesis in which members of these groups have become ecological equivalents. Although actual tent-making has been observed in only one bat species to date, we suggest that the principal selective force leading to the evolution of tent-making is a polygynous mating system whereby males construct tents to gain access to females. Tents in turn provide resources that offer protection from predators and inclement weather.  相似文献   

18.
Flow-cytometric analyses of 29 species of microchiropteran bats representing four families and 20 genera revealed that bats possess only 79% (5.43 pg) of the DNA content of a “typical” mammal (e.g., Mus musculus strain C57BL; 7 pg). Chiroptera, the second largest order of mammals, is thus an exception to the prevailing view that mammals possess a minimum nuclear DNA content of 7 pg. Limitations on cell size resulting from a high metabolic rate may have constrained evolution of DNA content and could explain why the extensive heterochromatic additions that are common in some groups of mammals are absent in bats. Chromosomes of bats have been well studied; detailed chromosomal banding data are available for nearly all the species used in this investigation. However, no significant correlations were found between DNA content and karyotypic characteristics such as 2n, fundamental number, and rate or pattern of chromosomal evolution.  相似文献   

19.
A new genus and species of emballonurid microchiropteran,Tachypteron franzeni, is described from the early Middle Eocene (MP 11) of Grube Messel, near Darmstadt, Germany. The holotype is extraordinarily well-preserved. It is the first unequivocal representative of an extant clade among Messel bats and the oldest unequivocal record of Emballonuridae. The flight apparatus ofT. franzeni is highly specialized for a rapid and constant flight style. The proportions of the strikingly narrow wing, the outline of the flight membranes and external ear, the morphology of the postcranial skeleton, and the relative cochlea size ofT. franzeni and extantTaphozous species are almost identical, while the dentition ofT. franzeni is distinguished by more plesiomorphic features.Tachypteron and the fairly diverse Paleogene record of emballonurids from France, consisting mainly of isolated teeth, document the earliest radiation known from an extant bat family and suggest a rather intense pre-Middle Eocene diversification of emballonurids.  相似文献   

20.
Although the land mammals of Madagascar have been the subject of many studies, the island’s bats have yet to feature prominently on the research or conservation agenda. In this study we used mist nets, acoustic sampling and cave surveys to assess habitat use, seasonality and roost selection. Four microchiropteran species (Triaenops rufus, T. furculus, Miniopterus manavi and Myotis goudoti) appeared to be strongly associated with the forest interior based on trapping, but analysis of time-expanded echolocation recordings revealed that T. rufus and M.␣manavi were frequently recorded in forest edges and clearings. Bat activity was significantly lower inside the forest than at the interface between agricultural land and forest. The caves visited most often by tourists were low in bat abundance and species richness. Anjohikinakina Cave, which was visited infrequently by people, was used by five species and contained between 54% (winter) and 99% (summer) of bats counted in 16 caves and is a site of national importance for bat conservation. Hipposideros commersoni was only netted in our study area during October and may be a migrant to the site or present but inactive during the austral winter. The forest surrounding the caves is therefore important because it provides cover for emerging bats and a potential source of invertebrate prey whilst the forest edge is important to foraging bats.  相似文献   

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