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Notes on the anatomy of the tree shrew Dendrogale
... Highly insectivorous, rarely relies on fruit or plants. Davis (1938); Kvartalnov (2009) ...
... Our results are consistent with the proposition that this species is highly insectivorous. Dendrogale murina has dental morphology that is consistent with a higher level of frugivory (i.e., lower average values for DNE and 3D-OPCR, but with relatively high relief; Fig. 2), which is surprising as this species has been described as being highly insectivorous, rarely relying on plant material (Davis 1938;Kvartalnov 2009). This could be a product of fallback foods shaping the dental morphology of this taxon, though more empirical data are needed. ...
... Further research is needed to determine how the dental adaptations and ecology of treeshrews has evolved, what the ecology of more plesiomorphic euarchontans such as mixodectids was, and to understand how the morphological patterns noted here relate to actual feeding patterns in the wild. Davis (1938) Unknown Dendrogale murina Stomach contents of one individual Harrison (1954) Unknown Dendrogale melanura Stomach contents of seven individuals Tupaia montana Stomach contents of 15 individuals Davis (1962) Collected over 2 years Tupaia longipes Stomach contents of six individuals Tupaia minor Stomach contents of seven individuals Tupaia tana Stomach contents of 10 individuals Lim (1967) Collected over 2 years Ptilocercus lowii Stomach contents of nine individuals D'Souza (1974) Short-term observational study Tupaia minor Stomach contents of 10 individuals and three observations Kawamichi and Kawamichi (1982) Collected over 6 months Tupaia glis Six sightings/ trappings near fig trees (Ficus dubai) Langham (1982) Collected over 3.5 years Tupaia glis Stomach contents of 30 individuals Langham (1983) Collected over 26 days Tupaia glis Stomach contents of 24 individuals Emmons (1991) Collected over ...
The ecology, and particularly the diet, of treeshrews (order Scandentia) is poorly understood compared to that of their close relatives, the primates. This stems partially from treeshrews having fast food transit times through the gut, meaning fecal and stomach samples only represent a small portion of the foodstuffs consumed in a given day. Moreover, treeshrews are difficult to observe in the wild, leading to a lack of observational data in the literature. Although treeshrews are mixed feeders, consuming both insects and fruit, it is currently unknown how the relative importance of these food types varies across Scandentia. Previous study of functional dental morphology has provided an alternative means for understanding the diet of living euarchontans. We used dental topographic metrics to quantify aspects of functional dental morphology in a large sample of treeshrews (n = 58). We measured relief index, Dirichlet normal energy, and three-dimensional orientation patch count rotated, which quantify crown relief, occlusal curvature, and complexity, respectively. Our results suggest that treeshrews exhibit dental morphology consistent with high levels of insectivory relative to other euarchontans. They also suggest that taxa such as Dendrogale melanura and Tupaia belangeri appear to be best suited to insectivory, whereas taxa such as T. palawanensis and T. gracilis appear to be best adapted to frugivory. Our results suggest that Ptilocercus lowii is characterized by a dentition better adapted to insectivory than the early primate Purgatorius. If P. lowii represents a good modern analogue for primitive euarchontans, this contrast would support models of primate origins that include a shift to greater frugivory.
... Classical studies of Le Gros Clark (1924 and Davis (1938) were devoted to the anatomy of tree shrews. Osteology and some groups of locomotor muscles were described by Carlsson (1922), Miller (1935), Verma (1965), George (1977), and Sargis (2002d). ...
... It inserts on the base of the greater tubercle of the humerus. Le Gros Clark (1924), Davis (1938), and Verma (1965) regarded the m. spinodeltoideus as the m. ...
... Sometimes the accessory portion is described as the separate muscle -m. spinohumeralis (Davis 1938;Le Gros Clark 1924). George (1977) regarded it as the part of the m. ...
This chapter includes four subchapters—Wing Membrane, Skeleton, Joints, and Musculature, which describe, respectively, the skin membrane, osteology, syndesmology, and myology of the shoulder girdle and forelimb in six species representing five families of bats, including fruit bats. The original myological data are compared to those published for 14 bat families (Humphry, J Anat Physiol 3(2):294–319, 1869; Macalister, Philos Trans R Soc Lond 162:125–172, 1872; Vaughan, Functional morphology of three bats: Eumops, Myotis, Macrotus, University of Kansas Publications, Museum of Natural History, 1–153, 1959; Vaughan, J Mammal 47(2):249–260, 1966; Vaughan and Bateman, J Mammal 51(2):217–235, 1970; Norberg, Arkr Zool 22(2):483–543, 1970; Norberg, Z Morph Tiere 73:1–44, 1972; Kovtun, Locomotor apparatus of bats, Naukova Dumka, Kiev, 1978; Strickler, Contrib Vertebr Evol 4:1–198, 1978; etc.). The description is supplied with 83 original illustrations including 70 black-and-white drawings of myological dissections, nine grayscale photos of the skeleton, five colored photos, and the X-ray frame sequence of the wing beat cycle of Rousettus aegyptiacus.
... Classical studies of Le Gros Clark (1924 and Davis (1938) were devoted to the anatomy of tree shrews. Osteology and some groups of locomotor muscles were described by Carlsson (1922), Miller (1935), Verma (1965), George (1977), and Sargis (2002d). ...
... It inserts on the base of the greater tubercle of the humerus. Le Gros Clark (1924), Davis (1938), and Verma (1965) regarded the m. spinodeltoideus as the m. ...
... Sometimes the accessory portion is described as the separate muscle -m. spinohumeralis (Davis 1938;Le Gros Clark 1924). George (1977) regarded it as the part of the m. ...
Various aspects of biology of colugos are considered, which have an influence upon their peculiar locomotion. The osteological, syndesmological and myological features described in Chap 2, are treated in accordance with the major types of locomotion of these animals (gliding, running and clinging on thick tree trunks, and suspending under branches). The corresponding mobility of the shoulder girdle elements is analyzed. Static models of the muscular forces in the forelimb and shoulder girdle are developed for the cases of gliding and clinging onto tree trunks. The chapter includes the following subchapters: Some Biological Aspects of Colugos; Gliding; Climbing up Trunks; Climbing under Branches; Mobility of Shoulder Girdle; Static Analysis of Clinging onto Trunk; Static Analysis of Gliding. It is supplied with 4 grayscale and 11 colored illustrations, which include original drawings representing kinematic and static models being considered, and the photos of alive flying lemurs which were kindly supplied by colleagues from Singapore.
... Classical studies of Le Gros Clark (1924 and Davis (1938) were devoted to the anatomy of tree shrews. Osteology and some groups of locomotor muscles were described by Carlsson (1922), Miller (1935), Verma (1965), George (1977), and Sargis (2002d). ...
... It inserts on the base of the greater tubercle of the humerus. Le Gros Clark (1924), Davis (1938), and Verma (1965) regarded the m. spinodeltoideus as the m. ...
... Sometimes the accessory portion is described as the separate muscle -m. spinohumeralis (Davis 1938;Le Gros Clark 1924). George (1977) regarded it as the part of the m. ...
The chapter includes three subchapters—Skeleton, Joints and Musculature, which describe, respectively, osteology, syndesmology and myology of the shoulder girdle and forelimb in Tupaia belangeri, one of the most generalized members of the order Scandentia. The original myological data are compared with those published by Le Gros Clark, Davis, Miller, Verma, George, Sargis, etc. on the other tree shrews, namely, Dendrogale
murina, Ptilocercus
lowii, Tupaia glis, Tupaia minor, Tupaia nicobarica, Tupaia tana and Urogale evereti. The description is supplied with 52 original illustrations—45 black-and-white drawings of myological dissections, 6 grayscale and 1 coloured photos of the skeleton.
... Classical studies of Le Gros Clark (1924 and Davis (1938) were devoted to the anatomy of tree shrews. Osteology and some groups of locomotor muscles were described by Carlsson (1922), Miller (1935), Verma (1965), George (1977), and Sargis (2002d). ...
... It inserts on the base of the greater tubercle of the humerus. Le Gros Clark (1924), Davis (1938), and Verma (1965) regarded the m. spinodeltoideus as the m. ...
... Sometimes the accessory portion is described as the separate muscle -m. spinohumeralis (Davis 1938;Le Gros Clark 1924). George (1977) regarded it as the part of the m. ...
Various aspects of bat locomotion are considered, including terrestrial one. Wingbeat cycle and interaction of the wing with the air are discussed in detail. A new model of the shoulder girdle mobility in flight is established, which differs significantly from the common point of view. Static model of the muscular forces in the forelimb and shoulder girdle is developed for the case of mid-downstroke in forward flight. Specific features of the forelimb musculature in bats are interpreted in functional terms. The chapter includes the following subchapters: Locomotor Features of Chiropterans; Kinematics of Chiropteran Wing; Interaction of Wing with Air; Internal Biomechanics of Wing; Static Analysis of Downstroke. It is supplied with 2 grayscale and 10 colored illustrations, which include the photos of alive bats, original drawings representing kinematic and static models being considered, and additional X-ray frame sequences of the wingbeat cycle of Rousettus aegyptiacus.
... More particularly, the Northern smooth-tailed treeshrew Dendrogale murina (Schlegel and Muller, 1843) is a small (45 g) diurnal treeshrew using the ground and the understory of forests, bushes, savannas and bamboo thickets (Lekagul and McNeely 1977, Timmins et al. 2003, Kvartalnov 2009). The species forages for arthropods at heights ~5 m and in the forest litter, and rarely feeds on fruit or other plant material (Davis 1938, Kvartalnov 2009). On the ground, the animals run, bound and jump between roots and rocks (Kloss 1916, Kvartalnov 2009), whereas on the trees they clamber, climb, and jump between branch and bamboo entanglements (Timmins et al. 2003, Kvartalnov 2009). ...
... These behaviors suggest that Northern smoothtailed treeshrews would be capable of hallucal grasping, but to what extent is unknown. The postcranial morphology and muscular anatomy of Dendrogale partly resemble that of Ptilocercus, and are functionally associated with forelimb protraction and flexion, hind limb flexion and foot plantar flexion and inversion (Davis 1938, Riesenfeld 1974, Stafford and Thorington 1998, Endo et al. 1999, Sargis 2002a. However, Dendrogale is more similar to other tupaiids than to Ptilocercus (Sargis 2002a,b,c,d). ...
... Smooth-tailed treeshrews, Dendrogale, are considered the most basally divergent tupaiids, having diverged from the rest of the family at 34.77 mya (Butler 1980, Luckett 1980, Olson et al. 2004, 2005, Roberts et al. 2011). Their small body mass (~45 g), in combination with several cranial, dental, postcranial characters and mainly arboreal adaptations and behavior indicate their primitive nature (Davis 1938, Butler 1980, Luckett 1980, Szalay and Drawhorn 1980, Szalay and Dagosto 1988, Endo et al. 1999, Sargis 2002a,b,c, Kvartalnov 2009). Therefore, their phylogenetic position is very important for understanding pedal grasping evolution within euarchontan mammals. ...
Pedal grasping evolution in euarchontan mammals is of great importance as it bears on the adaptive significance of specialized hallucal grasping and arboreal niche use related to the group differentiation. Basally divergent arboreal tupaiid treeshrews are very suitable for testing pedal grasping modes and associated substrate correlates and provide insights on euarchontan pedal evolution. For these purposes we filmed wild-caught Dendrogale murina from Vietnam and analyzed their foot mechanisms. Our observations showed that hallucal grasp was moderately used and was mainly associated with small and horizontal substrates. Convergent grasp was frequently used on medium-sized and horizontal substrates whereas claws were related to large and vertical substrates. In addition, the foot was frequently inverted and mainly placed in a semiplantigrade position. Inversion and semiplantigrady dominated on small, medium-sized and horizontal substrates but decreased on larger substrates with increased inclinations. The observed pedal mechanism probably represents a derived condition, where hallucal grasping tends to become slightly restrained, compared to the primitive euarchontan (and scandentian) pedal grasping mechanism. Furthermore, it hallmarks an early stage in tupaiid evolution towards a more constrained pedal grasping. This further substantiates pedal grasping plasticity within euarchontan mammals and highlights the strong relation between a hallucal grasping mechanism and the frequent and primary use of small slender substrates.
... Classical studies of Le Gros Clark (1924 and Davis (1938) were devoted to the anatomy of tree shrews. Osteology and some groups of locomotor muscles were described by Carlsson (1922), Miller (1935), Verma (1965), George (1977), and Sargis (2002d). ...
... It inserts on the base of the greater tubercle of the humerus. Le Gros Clark (1924), Davis (1938), and Verma (1965) regarded the m. spinodeltoideus as the m. ...
... Sometimes the accessory portion is described as the separate muscle -m. spinohumeralis (Davis 1938;Le Gros Clark 1924). George (1977) regarded it as the part of the m. ...
This book offers a new explanation for the development of flight in mammals and offers detailed morphological descriptions of mammals with flapping flight. The skeletomuscular apparatus of the shoulder girdle and forelimbs of tree shrews, flying lemurs and bats is described in detail. Special attention is paid to the recognition of peculiar features of the skeleton and joints. For the basic locomotor patterns of flying lemurs and bats, the kinematic models of the shoulder girdle elements are developed. The most important locomotor postures of these animals are analyzed by means of statics. The key structural characters of the shoulder girdle and forelimbs of flying lemurs and bats, the formation of which provided transition of mammals from terrestrial locomotion to gliding and then, to flapping flight, are recognized. The concept is proposed that preadaptations preceding the acquisition of flapping flight could have come from widely sprawled forelimb posture while gliding from tree to tree and running up the thick trunks. It is shown that flying lemur is an adequate morphofunctional model for an ancestral stage of bats. The evolutionary ecomorphological scenario describing probable transformational stages of typical parasagittal limbs of chiropteran ancestors into wings is developed.
... Several studies of tree shrews (Scandentia, Tupaiidae) have included descriptions of the vertebrae and ribs. These studies have been conducted both on the only ptilocercine tupaiid, Ptilocercus lowii (Le Gros Clark, 1926), as well as on the tupaiines Dendrogale and Anathana (Davis, 1938;Verma, 1965), but they all have lacked a functional±adaptive perspective. Jenkins (1974), however, did perform a functional analysis of the thoracic and lumbar vertebrae of the tupaiine Tupaia glis after he observed pronounced¯exion and extension (in the sagittal plane) of the trunk during locomotion (especially during the bounding run, when speed is maximized). ...
... Schultz (1961), on the other hand, determined that the average number of vertebrae for Tupaia is 7C, 13T, 6L, 3S and 24 caudal vertebrae (see also Lyon, 1913). The same number of precaudal vertebrae is also found in the tupaiines Dendrogale (Davis, 1938) and Anathana (Verma, 1965). I have con®rmed these precaudal counts for Ptilocercus, Tupaia and Dendrogale, as well as counted the number of precaudal vertebrae in Urogale, which, like the other tupaiines, has 7C, 13T, 6L and 3S. ...
... Le Gros Clark (1926) noted that the ®rst two sacral vertebrae of Ptilocercus articulate with the ilia. Davis (1938) stated that in Dendrogale, a tupaiine, only the ®rst sacral vertebra articulates with the ilia as in Tupaia. The articulation of the ®rst two sacral vertebrae with the ilia in Ptilocercus may again increase stability, while the tupaiine condition allows greater mobility. ...
In this study, the axial skeleton of 14 species of tupaiids (tree shrews) was analysed functionally and compared to that of other archontan mammals. Several differences that relate to differential substrate use were found in the ribs and vertebrae. These differences included cranio-caudal width of the ribs; number of thoracic, lumbar, and caudal vertebrae; cranio-caudal width of the atlas; orientation of the spinous process of the axis; length and cranio-caudal width of the spinous processes of the thoracic vertebrae; length of the spinous processes of the lumbar vertebrae; length and orientation of the transverse processes of the lumbar vertebrae; and the number of sacral vertebrae that articulate with the ilia. The ribs and vertebrae of the arboreal Ptilocercus lowii, the only ptilocercine, exhibit adaptations for a stable thorax that probably facilitate bridging locomotion. The vertebral columns of tupaiines, on the other hand, are more mobile and allow more flexion and extension of the spine; this increased flexion and extension increases stride length, which in turn increases speed in bounding or galloping mammals such as terrestrial tupaiines. It is proposed here that the attributes of the thorax of Ptilocercus are primitive for the Tupaiidae, that the ancestral tupaiid was arboreal, that the tupaiine condition is derived, and that the ancestral tupaiine was terrestrial. It is also proposed that: Ptilocercus may be primitive for the Archonta in its axial skeletal features; a stable thorax was first evolved in an arboreal ancestral archontan; the adaptations for stability of the thorax were retained in the Volitantia (dermopterans and chiropterans) for certain locomotor types, including gliding or flying; a mobile thorax evolved in conjunction with the shift to graspleaping in the ancestral euprimate. These scenarios may be further tested by quantitative analyses of vertebral osteology, as well as myological analyses of the epaxial musculature.
... Compared to disagreements about treeshrew generic distinction, the division of the family Tupaiidae into two subfamilies, Tupaiinae and Ptilocercinae (both of which have recently been elevated to familial rank; see below), has been far less contentious. Only Davis (1938) has opposed this separation, arguing that Dendrogale is morphologically intermediate between Ptilocercus and tupaiines, but the separation of Ptilocercus has been reaffirmed in numerous studies (e.g., Le Gros Clark, 1926;Steele, 1973;Butler, 1980;Luckett, 1980;Zeller, 1986a,b;Sargis, 2000Sargis, , 2001Sargis, , 2002bSargis, ,d, 2004). Furthermore, most authors agree that Ptilocercus is the living treeshrew that most closely resembles the ancestral scandentian in both its ecology and its morphological attributes (e.g., Le Gros Clark, 1926;Campbell, 1974;Gould, 1978;Butler, 1980;Szalay and Drawhorn, 1980;Martin, 1990;Lucas, 1993, 1996;Emmons, 2000;Sargis, 2000Sargis, , 2001Sargis, , 2002bSargis, ,d, 2004. ...
... Because we used Ptilocercus to root all trees, however, this by itself is an invalid test of Dendrogale's position relative to the remaining tupaiids. Davis (1938) argued that Dendrogale, rather than Ptilocercus, was the most primitive living treeshrew (and, by extension, the most basal), although subsequent authors have not endorsed this position. Luckett (1980) used the hypothetical ancestral eutherian condition in 15 characters to support the more widely accepted view that Ptilocercus represents the sister taxon to the remaining treeshrews (Lyon, 1913;Le Gros Clark, 1926;Napier and Napier, 1967;Martin, 1968Martin, , 1990Martin, , 2001Steele, 1973;Butler, 1980;Zeller, 1986a,b;Corbet and Hill, 1992;Wilson, 1993;Nowak, 1999;Sargis, 2000Sargis, , 2001Sargis, , 2002aSargis, ,b,c,d, 2004contra Davis, 1938). ...
... Both Luckett (1980) and Butler (1980) coded Dendrogale as possessing a doublerooted upper canine, a condition likewise noted by Davis (1938) in his seminal monograph on this genus. Steele (1973) coded Dendrogale as having the single-rooted condition, yet this appears to be one of many inconsistencies between his character matrix (his fig. ...
Although the supraordinal relationships of Scandentia (treeshrews) have been studied in great detail from both morphological and molecular perspectives, the phylogenetic relationships among treeshrews have been largely ignored. Here we review several published studies of qualitative morphological variation among living treeshrews and their contribution to our understanding of intraordinal phylogenetic relationships. Reanalysis of the data from each of these studies demonstrates that none of the trees in the original publications represents the most parsimonious interpretation. In addition to performing new analyses, we argue that all such studies to date suffer from one or more fundamental shortcomings, notably the failure to include reference to nonscandentian outgroups and the a priori assumption of generic monophyly of the relatively speciose genus Tupaia. Parsimony analyses of these data sets fail to resolve either intergeneric or interspecific relationships. Finally, several inconsistencies and conflicts with respect to character coding both within and between published studies are discussed. We conclude that a more rigorous investigation of morphological character state variation is sorely needed, one that explicitly identifies voucher specimens and does not make any assumptions of generic monophyly. This is necessary not only for the purpose of resolving phylogenetic relationships, but also for inference of ancestral states in a group that continues to figure prominently in studies of placental mammal diversification.
... 2a in Stafford and Thorington, 1998, for a scanning electron micrograph of the same carpus shown in Fig. 19 that shows the groove between the scaphoid and lunate better than the figure presented here). However, while the scaphoid and lunate of Ptilocercus and Dendrogale are not as completely fused as they are in Tupaia, Anathana, and Urogale (see Fig. 21), they are indeed fused (Figs. 20, 21;contra Le Gros Clark, 1926;Davis, 1938;George, 1977;Novacek, 1980;Stafford and Thorington, 1998). I suspect that any attempt to separate the scapholunate of Ptilocercus or Dendrogale would result in breakage. ...
... First, I should say that Stafford and Thorington (1998) have cleared up much of the confusion that has existed regarding this topic in tupaiid carpal morphology. For instance, Davis' (1938) comments concerning the fusion of the scaphoid and lunate in Dendrogale are confusing because he said that "the scaphoid and lunar are separate," and then later in the same paragraph he referred to "the fused condition of the scaphoid and lunar in Dendrogale" (p. 386). ...
... 386). Also, despite the fact that Flower (1885), Lyon (1913), and Davis (1938), for example, had reported the fusion of the scaphoid and lunate in Tupaia and George (1977) had reported the fusion of these bones in Tupaia, Urogale, and Anathana, Novacek (1980) still scored these bones as being unfused in Tupaiinae for his phylogenetic analysis (see Novacek, 1980, fig. 23; table 5). ...
In this study, the forelimb of 12 species of tupaiids was analyzed functionally and compared to that of other archontan mammals. Several differences that relate to differential substrate use were found in the forelimb morphology of tupaiids. These differences included shape of the scapula, length and orientation of the coracoid process, size of the lesser tuberosity, shape of the capitulum, length of the olecranon process, and shape of the radial head and central fossa. The forelimb of the arboreal Ptilocercus lowii, the only ptilocercine, is better adapted for arboreal locomotion, while that of tupaiines is better adapted for terrestrial (or scansorial) locomotion. While the forelimb of the arboreal Ptilocercus appears to be habitually flexed and exhibits more mobility in its joints, a necessity for movement on uneven, discontinuous arboreal supports, all tupaiines are characterized by more extended forelimbs and less mobility in their joints. These restricted joints limit movements more to the parasagittal plane, which increases the efficiency of locomotion on a more even and continuous surface like the ground. Even the most arboreal tupaiines remain similar to their terrestrial relatives in their forelimb morphology, which probably reflects the terrestrial ancestry of Tupaiinae (but not Tupaiidae). The forelimb of Urogale everetti is unique among tupaiines in that it exhibits adaptations for scratch-digging. Several features of the tupaiid forelimb reflect the arboreal ancestry of Tupaiidae and it is proposed that the ancestral tupaiid was arboreal like Ptilocercus. Also, compared to the forelimb character states of tupaiines, those of Ptilocercus are more similar to those of other archontans and it is proposed that the attributes of the forelimb of Ptilocercus are primitive for the Tupaiidae. Hence, Ptilocercus should be considered in any phylogenetic analysis that includes Scandentia.
... (2) relationships of fossils, and (3) biogeography of the group. Concerning the Wrst of these topics, Sargis (2000Sargis ( , 2002aSargis ( ,b, 2004 has proposed several hypotheses of scandentian postcranial evolution (see also Szalay and Drawhorn, 1980), and similar hypotheses of craniodental and soft tissue evolution have been proposed as well (e.g., Butler, 1980;Davis, 1938;Le Gros Clark, 1926;Lyon, 1913). All of these hypotheses of morphological evolution can be tested once a well-supported phylogeny is available. ...
... This division, whether at the familial or subfamilial level, has gone largely unchallenged. However, Davis (1938) proposed that Lyon's (1913) division of the family into two subfamilies was invalid because Dendrogale is morphologically intermediate between Ptilocercus and other treeshrews. This proposal has, however, been repeatedly rejected in other studies of treeshrew morphology and taxonomy (Butler, 1980;Corbet and Hill, 1992;Le Gros Clark, 1926;Luckett, 1980;Martin, 1990Martin, , 2001Napier and Napier, 1967;Nowak, 1999;Steele, 1973;Wilson, 1993). ...
... This proposal has, however, been repeatedly rejected in other studies of treeshrew morphology and taxonomy (Butler, 1980;Corbet and Hill, 1992;Le Gros Clark, 1926;Luckett, 1980;Martin, 1990Martin, , 2001Napier and Napier, 1967;Nowak, 1999;Steele, 1973;Wilson, 1993). Davis (1938) also suggested that Dendrogale may be the most primitive treeshrew, which contradicted Le Gros Clark's (1926) contention that Ptilocercus is the most primitive living treeshrew. Again, Davis' suggestion has not been supported by subsequent studies, which have instead upheld Le Gros Clark's hypothesis (e.g., Emmons, 2000;Martin, 1990;Sargis, 2002aSargis, ,b, 2004Szalay and Drawhorn, 1980). ...
Despite their traditional and continuing prominence in studies of interordinal mammalian phylogenetics, treeshrews (order Scandentia) remain relatively unstudied with respect to their intraordinal relationships. At the same time, significant morphological variation among living treeshrews has been shown to have direct relevance to higher-level interpretations of character state change as reconstructed in traditional interordinal studies, which have often included only a single species of treeshrew. Therefore, the importance of resolving relationships among treeshrews extends well beyond a better understanding of patterns of diversification within the order. A recent review highlighted several shortcomings in published studies of treeshrew phylogenetics based on morphology. Here we present the first investigation of treeshrew phylogenetics based on DNA sequences, utilizing previously published sequences from the mitochondrial 12S rRNA gene and combining them with newly generated sequence data from 15 species. Parsimony, likelihood, and Bayesian analyses all strongly support a sister relationship between Ptilocercus and the remaining species, further substantiating its recent elevation to familial status. Dendrogale is consistently recovered as the next taxon to diverge, but relationships among the remaining taxa are poorly supported by these data. We provide evidence for a relatively rapid radiation within the genera Tupaia and Urogale, but limited resolution precludes more than a cursory interpretation of biogeographic patterns.
Comparative anatomy the basis for studies of evolution, and radiographic and tomographic aspects, as auxiliary methods in the investigation of anatomical particularities, reinforce evolutionary research. Therefore, the aim of this study was to describe the vertebrae, sternum, and ribs of the capuchin monkey (Sapajus libidinosus) by means of anatomical dissection and radiographic and tomographic images. To this purpose, four cadavers were used in the anatomical analysis and five living animals for the imaging exams. The bones were described and compared with data from other primates species found in literature. Student's t-test for independent samples was performed. The vertebral column of the comprises seven cervical, 13 or 14 thoracic, five or six lumbar, two or three sacral, and 23 or 24 caudal vertebrae. The atlas is characterized by three foramina on the wing. The seventh cervical vertebra had a transverse foramen in one specimen. The anticlinal vertebra is always the penultimate thoracic one, the ninth pair of ribs is always the last sternal pair, and the last two are buoyant. The sternal was composed of five or six sternebrae. The lumbar vertebrae showed a bifurcated spinous process. Three different sacral morphologies were observed. The structures identified macroscopically could be well determined through radiographic and tomographic images. S. libidinosus presented anatomical characteristics more similar to those of man and of platirrinos monkeys. The knowledge obtained by macroscopic anatomy and tomographic and radiological exams contributes significantly to comparative evolutionary studies.
The mammalian nervous system is composed of (1) nervous elements, which are highly specialized for irritability and conductivity, and (2) supportive non-nervous elements. The nervous elements are called neurons and the supportive elements are the neuroglial cells and a limited amount of connective tissue.
Fossils directly contribute to the construction of phylogenies in two ways. They provide additional samples (usually taxa) which are used in biological comparisons, so far as the completeness of the fossil material warrants, in order to determine morphocline polarity; that is, in forming a hypothesis of primitive and derived character states. In addition, fossils provide a temporal frame of reference (see Luckett, this volume) which makes the phylogeny more complete and practical in terms of geological applications. Although geologic age is not a biological attribute of a taxon, it follows that for a lineage with a reasonably complete fossil record, older taxa often (but not always) are on average more primitive than younger taxa, simply because ancestors must occur before descendants. Therefore, a sequence of fossils may reflect ancestor-descendant relationships, even if the fossils in hand are not themselves the actual ancestors or descendants.
The lack of unquestioned early Tertiary fossil tupaiids has stimulated a search for morphological, developmental, molecular, and behavioral features of extant tree shrews which might provide insight into their evolutionary relationships with primates or other eutherians. Reproductive features were among the earliest to be cited as evidence of a special tupaiid-primate relationship. Kaudern (1911) was one of the first investigators to suggest close affinities between tupaiids and primates as a result of his comparative studies on the male reproductive system in Tupaiidae, Macroscelididae, Lipotyphla, and Lemuroidea. He concluded that the male reproductive system provided no evidence of special affinities between tupaiids and macroscelidids; instead, he emphasized the occurrence of scrotal testes and seminal vesicles as shared similarities which supported the classification of tupaiids with Primates rather than Insectivora. These reproductive similarities were also cited as evidence of a close tupaiid-primate relationship by Carlsson (1922) in her extensive analysis of cranioskeletal and soft anatomical features in insectivores and prosimians. Subsequently, developmental characters of the fetal membranes and placenta, particularly the nature of the definitive placenta and allantois, were also utilized to support the hypothesis of primate affinities for tree shrews (Meister and Davis, 1956, 1958; Le Gros Clark, 1959, 1971).
The Eocene fossil record of bats (Chiroptera) includes four genera known from relatively complete skeletons: lcaronycteris, Archaeonycteris, Hassianycteris, and Palaeochiropteryx. Phylogenetic relationships of these taxa to each other and to extant lineages of bats were investigated in a parsimony analysis of 195 morphological characters, 12 rDNA restriction site characters, and one character based on the number of R-1 tandem repeats in the mtDNA d-loop region. Results indicate that lcaronycteris, Archaeonycteris, Hassianycteris, and Palaeochiropteryx represent a series of consecutive sister-taxa to extant microchiropteran bats. This conclusion stands in contrast to previous suggestions that these fossil forms represent either a primitive grade ancestral to both Megachiroptera and Microchiroptera (e.g., Eochiroptera) or a separate clade within Microchiroptera (e.g., Palaeochiropterygoidea). A new higher-level classification is proposed to better reflect hypothesized relationships among Eocene fossil bats and extant taxa. Critical features of this classification include restriction of Microchiroptera to the smallest clade that includes all extant bats that use sophisticated echolocation (Emballonuridae + Yinochiroptera + Yangochiroptera), and formal recognition of two more inclusive clades that encompass Microchiroptera plus the four fossil genera. Comparisons of results of separate phylogenetic analyses including and subsequently excluding the fossil taxa indicate that inclusion of the fossils changes the results in two ways: (1) altering perceived relationships among extant forms at a few poorly supported nodes; and (2) reducing perceived support for some nodes near the base of the tree. Inclusion of the fossils affects some character polarities (hence slightly changing tree topology), and also changes the levels at which transformations appear to apply (hence altering perceived support for some clades). Results of an additional phylogenetic analysis in which soft-tissue and molecular characters were excluded from consideration indicate that these characters are critical for determination of relationships among extant lineages. Our phytogeny provides a basis for evaluating previous hypotheses on the evolution of flight, echolocation, and foraging strategies. We propose that flight evolved before echolocation, and that the first bats used vision for orientation in their arboreal/aerial environment. The evolution of flight was followed by the origin of low-duty-cycle laryngeal echolocation in early members of the microchiropteran lineage. This system was most likely simple at first, permitting orientation and obstacle detection but not detection or tracking of airborne prey. Owing to the mechanical coupling of ventilation and flight, the energy costs of echolocation to flying bats were relatively low. In contrast, the benefits of aerial insectivory were substantial, and a more sophisticated low-duty-cycle echolocation system capable of detecting, tracking, and assessing airborne prey subsequently evolved rapidly. The need for an increasingly derived auditory system, together with limits on body size imposed by the mechanics of flight, echolocation, and prey capture, may have resulted in reduction and simplification of the visual system as echolocation became increasingly important. Our analysis confirms previous suggestions that Icaronycteris, Archaeonycteris, Hassianycteris, and Palaeochiropteryx used echolocation. Foraging strategies of these forms were reconstructed based on postcranial osteology and wing form, cochlear size, and stomach contents. In the context of our phylogeny, we suggest that foraging behavior in the microchiropteran lineage evolved in a series of steps: (1) gleaning food objects during short flights from a perch using vision for orientation and obstacle detection; prey detection by passive means, including vision and/or listening for prey-generated sounds (no known examples in fossil record); (2) gleaning stationary prey from a perch using echolocation and vision for orientation and obstacle detection; prey detection by passive means (Icaronycteris, Archaeonycteris); (3) perch hunting for both stationary and flying prey using echolocation and vision for orientation and obstacle detection; prey detection and tracking using echolocation for flying prey and passive means for stationary prey (no known example, although Icaronycteris and/or Archaeonycteris may have done this at times); (4) combined perch hunting and continuous aerial hawking using echolocation and vision for orientation and obstacle detection; prey detection and tracking using echolocation for flying prey and passive means for stationary prey; calcar-supported uropatagium used for prey capture (common ancestor of Hassianycteris and Palaeochiropteryx; retained in Palaeochiropteryx); (5) exclusive reliance on continuous aerial hawking using echolocation and vision for orientation and obstacle detection; prey detection and tracking using echolocation (Hassianycteris; common ancestor of Microchiroptera). The transition to using echolocation to detect and track prey would have been difficult in cluttered envionments owing to interference produced by multiple returning echoes. We therefore propose that this transition occurred in bats that foraged in forest gaps and along the edges of lakes and rivers in situations where potential perch sites were adjacent to relatively clutter-free open spaces. Aerial hawking using echolocation to detect, track, and evalute prey was apparently the primitive foraging strategy for Microchiroptera. This implies that gleaning, passive prey detection, and perch hunting among extant microchiropterans are secondarily derived specializations rather than retentions of primitive habits. Each of these habits has apparently evolved multiple times. The evolution of continuous aerial hawking may have been the "key innovation" responsible for the burst of diversification in microchiropteran bats that occurred during the Eocene. Fossils referable to six major extant lineages are known from Middle-Late Eocene deposits, and reconstruction of ghost lineages leads to the conclusion that at least seven more extant lineages were minimally present by the end of the Eocene.
The main features of ecology and behavior of the slender-tailed tree-shrew based on the observations in southern Vietnam, at the Cat Tien National Park (11°25' N, 107°25' E) are described. Slender-tailed treeshrews inhabit parts of forests, where bamboo or rattans grow, abandoned gardens and fields overgrowing with tall grasses and bamboo. They consume insects and spiders found on the ground surface and in leaf piles, seek invertebrates inside rotten trunks. Tree-shrews trace birds and catch disturbed prey; sometimes, they try to steal food caught by birds. Usually, these shrews build individual nests with dry leaves for night rest at open places without any shelters. During the period of observations (November - June), tree-shrews were found in pairs at small (-0.5 ha) territories. The animals in pairs maintained visual or acoustic contacts with each other. They designated territories by cries and odor marks that were left on bamboo stems or rattan lianas. Several territorial conflicts were observed. Copulations took place in February - March, young animals occurred in March - April. In spite of the active use of the ground surface, the slender-tailed tree-shrew has locomotion typical for an arboreal animal, in contrast to the majority of representatives of the Tupaiidae family.
The tree shrews (family Tupaiidae) of Southeast Asia are small, scansorial, squirrel-like mammals which occupy a range of arboreal, semi-arboreal, and forest floor niches. They are insectivorous/omnivorous and predominantly diurnal, although one species (Ptilocercus lowii) is crepuscular or nocturnal. The only monographic description of all genera and species of the family was that by Lyon (1913). Most taxonomists have accepted Lyon’s subdivision of Tupaiidae into two subfamilies: (1) the diurnal subfamily Tupaiinae, containing five genera (Tupaia, Anathana, Dendrogale, Lyonogale, and Urogale); and (2) the crepuscular (or nocturnal) subfamily Ptilocercinae, containing the single genus Ptilocercus. The geographic distribution of the family extends from India to the Philippines, and from southern China to Java, Borneo, Sumatra, and Bali, including the many islands within this region. This distribution corresponds closely with the limits of the Zoogeographic Oriental Region.
The interspecific relationships and biogeography of seven southeast Asian tree shrew species in the genus Tupaia were examined by DNA hybridization and multivariate morphometric analysis. Urogale everetti served as the outgroup. DNA hybridization data indicate that T. tana is most closely related to T. montana, and they form a clade with T. minor. Morphometric comparisons indicate that T. tana and T. minor, and T. montana and T. palawanensis, form groups that, together, are most similar to T. glis. T. javanica and U. everetti cluster outside the rest of Tupaia. The DNA hybridization data support a model of Bornean speciation driven by sea-level changes. They also indicate either (1) that there is a large variation in the rate of tree shrew evolution or (2) that U. everetti may in fact be a member of the ingroup. When considered in light of the phylogenetic results, the morphometric data suggest substantial convergence in body size or correlation in character changes.
The interspecific relationships and biogeography of seven southeast Asian tree shrew species in the genus Tupaia were examined by DNA hybridization and multivariate morphometric analysis. Urogale everetti served as the outgroup. DNA hybridization data indicate that T. tana is most closely related to T. tnontana, and they form a clade with T. minor. Morphometric comparisons indicate that T. tana and 77 minor, and 7. montana and T palawanensis, form groups that, together, are most similar to T. glis. T. javanica and U. everetti cluster outside the rest of Tupaia. The DNA hybridization data support a model of Bornean speciation driven by sea-level changes. They also indicate either (1) that there is a large variation in the rate of tree shrew evolution or (2) that U. everetti may in fact be a member of the ingroup. When considered in light of the phylogenetic results, the morphometric data suggest substantial convergence in body size or correlation in character changes.
In this study, multivariate analyses were conducted on the limb morphology of eleven species of tupaiids. Both a cluster analysis and a principal components analysis were performed. These analyses show that the limb morphology of the arboreal Ptilocercus lowii, the only ptilocercine, is very different from that of the mostly terrestrial tupaiines. These results confirm those of previous qualitative and univariate analyses, and they support the division of Tupaiidae into two subfamilies. The use of postcranial features to distinguish Ptilocercinae from Tupaiinae is important because previous taxonomic studies of tupaiids have only used cranial, dental, and external morphological characters to diagnose these subfamilies. The cluster analyses support the inclusion of Tupaia tana in Tupaia rather than Lyonogale, but, unfortunately, the results are ambiguous regarding the possible inclusion of Urogale everetti in Tupaia.
Four cervicobrachial plexuses from two colugos (Dermoptera), which are gliding mammals with semi-elongated necks, were dissected with imaging analysis and compared with those in its relatives, 12 sides of six treeshrews (Scandentia) and 32 sides of 16 strepsirrhines (Primates), for considering of its evolutionary constraint and functional adaptation. (1) The relative cervical length in the colugos was significantly longer than those in the others, regardless of the number and proportion of vertebrae. (2) In all examined colugos, the cervical plexus exhibited broader cervical root segments comprising the hypoglossal (N. XII) and first to fifth cervical (C1-C5) nerves, whereas the brachial plexus exhibited concentrated segments comprising C6 to the first thoracic nerve (T1) and part of T2. (3) On the other hand, the cervical plexus composed of N. XII and C1-C4 and the brachial plexus composed of C5-T1(2) were formed in all treeshrews (12/12 sides, 100.0%) and most strepsirrhines (27/32 sides, 84.4%) as seen in most terrestrial placental mammals. (4) Similar root segments of broader cervical and concentrated brachial plexuses were found in five sides of three strepsirrhines (15.6%), which are species with somewhat longer necks than the other strepsirrhines and treeshrews. Based on present and previous reports on elongated and shortened neck mammals, the modified root segments of the cervicobrachial plexus in the colugo appears to be related more to neck length than to its ecological habit, specialized locomotion, or any phylogenetic constraint.
1. The few historical records of Dendrogale murina are from southern Vietnam, South-east Thailand and probably Cambodia. Recent records extend its range considerably further north in Vietnam, into Laos, and provide the first certain Cambodian localities. Its occurrence within its range is patchy, and while in some areas (Cat Tien National Park, Vietnam, and a part of Mondulkiri Province, Cambodia) it is clearly common, elsewhere records are infrequent. Dendrogale murina seems to be relatively easy to observe, so the documented range for Laos, Vietnam and Thailand probably approximates to the real range. Cambodia has not been surveyed extensively enough to propose a provisional distribution.
2. There is no obvious ecological correlate of species occurrence: most sites have extensive bamboo, but various other similar sites surveyed within its range lack records. Most records come from evergreen forest (at varying stages of degradation) but D. murina has also been found in mixed deciduous forest, extensive secondary bamboo lacking any dicotyledonous canopy, and in streamside tangles amid rocky savannah. Records range from the plains up to 1500 m altitude.
3. The species mainly uses the under- and mid-storeys, but also enters the canopy. It is active at least throughout the daylight hours; nocturnal activity has not been assessed. Although the ecological needs are poorly understood, there is no reason to believe that D. murina is at any special risk and it is unlikely to meet any IUCN global threat criteria.
The Tree shrews (family Tupaiidae) were earlier grouped with the Elephant shrews (family Macroscelididae) in the suborder Menotyphla of the Insectivora. Following a proposal of Carlsson (1922), many workers, and notably Le Gros Clark, have presented evidence that the Tree shrews should be regarded as primitive or basal Primates. Simpson (1945) accepts them as such in his classification of the Mammalia. This view, because of the wide interdisciplinary interest in Primate evolution, has been widely accepted and has been of considerable influence. It has not, however, been without its opponents. This review critically analyses the evidence for and against accepting the Tree shrews as Primates.
Carpal morphology and development in bats, colugos, tree shrews, murids, and sciurids were studied in order to homologize carpal elements. Prenatal coalescence of discrete cartilaginous templates with a loss of a center of ossification appears to be the most common method of reducing carpal elements in these mammals. Only bats and colugos showed postnatal ossification between discrete elements as a method of reducing carpal elements. Carpal morphology of tree shrews is more diverse than previously reported. Ptilocercus shows a highly derived carpal morphology that may be related to its relatively greater arboreality. Dendrogale exhibits what is most likely the ancestral tupaiid carpal morphology. Carpal morphologies of Tupaia, Urogale, and Anathana are identical to each other. Carpal morphology differs between megachiropterans and microchiropterans. These differences may be related to different aerodynamic constraints between the suborders. The carpal morphology of microchiropterans is diverse and may reflect different adaptive regimes between microchiropteran families. Carpal morphology of the colugos shows both megachiropteran and microchiropteran characters. The function of these characters in colugos and bats (stabilization of the carpus in dorsiflexion) is proposed to be similar, although the locomotor roles may be quite different between these taxa. J. Morphol. 235:135–155, 1998. © 1998 Wiley-Liss, Inc.
The limb musculature of the tree shrews,Tupaia glis, Tupaia nicobarica, Lyonogale (Tupaia) tana, andUrogale everetti, is described and compared with published accounts. Although these species show preferences for different forest levels,
i.e., arboreal (T. nicobarica), semiarboreal (T. glis), and terrestrial (L. tana, U. everetti) niches, their musculoskeletal contrasts present no consistent patterns attributable to locomotor adaptations. However, a
re-examination of the myological evidence bearing on the much discussed question of the relationship of tree shrews to primates
suggests that those features shared by these forms are retentions from their basal mammalian heritage, and supports the view
that tree shrews possess a primitive rather than a progressive insectivoran limb morphology.
1Die geschichtlichen Veränderungen der Klassifikation der Tupaiidae sind kurz dargestellt. Ursprünglich gelten die Tupaiiden als ‘basale’, zuletzt aber allgemein als ‘fortgeschrittene’ Insektenfresser zwischen Lipotyphla und Primaten.2Die Benennung der Tupaia-Arten wird diskutiert, die Lyonsche Trennung der T. belangeri/T. chinensis- von der T. glis-Artengruppe wird übernommen. Die erste Gruppe unterscheidet sich von der zweiten durch die Brustwarzenzahl (3 Paare gegen 2 Paare). Demnach sind die meisten Arten, die in der neueren Literatur ‘T. glis’ heißen, richtig T. belangeri.3Eine Untersuchung der männlichen und weiblichen Geschlechtsorgane zeigt wesentliche Unterschiede zu den Primaten. Der andauernde descensus testiculorum bei Tupaiiden ist kein Zeichen einer Primatenverwandtschaft, da er unter Metatheria und Eutheria weit verbreitet ist und sogar ein schon im gemeinsamen Stamm der beiden Gruppen vorhandenes primitives Merkmal sein könnte. Die präpeniale Stellung der Hoden beim ♂ von Tupaia und das Fehlen eines Inguinalrings sind deutliche Unterschiede zu allen heute lebenden Primaten. (Da der Inguinalring fehlt, ist bei Tupaia das Zurückziehen der Hoden als Furchtreaktion möglich. Wohl deswegen gibt es frühere, unbestätigte Berichte, daß bei Ptilocercus der descensus jahreszeitlich (und nicht permanent) stattfindet.)Das ♀ unterscheidet sich durch einen gut ausgebildeten Urogenitalsinus von sämtlichen heute lebenden Primaten-♀♀. Das Ovarium von Tupaia ist morphologisch allgemein unspezialisiert, doch verschließt anscheinend ein besonderer Mechanismus die Ovarialtasche. ♀♀ und ♂♂ von Tupaia scheinen kein Baculum (os clitoridis bzw. os penis) zu besitzen, obwohl dieser Knochen bei lebenden Plazentaliern (einschließlich der Primaten) normalerweise vorhanden ist.4Die Plazentation von Tupaiiden steht unter den Säugetieren einzig da. Die Keimblase wird bilateral an vorgebildete ‘Plazentarkissen’ geheftet, es kommt zu einer bidiskoidalen Plazentation. Deren Ähnlichkeit mit der bidiskoidalen Plazentation einiger Anthropoiden ist rein äußerlich und systematisch unwesentlich. Der Plazentartyp der Tupaiiden ist, soweit man weiß, nicht labyrinth-haemochorial sondern labyrinth-endotheliochorial, und die Plazenten scheinen semi-deciduat zu sein. Contra-deciduate Plazentation mag manchmal als Abnormalität vorkommen. Wahrscheinlich ist die Plazentation der heute lebenden Tupaiiden eine höchst spezialisierte Entwicklung eines sehr frühen Säugetier-Plazentartyps.5Berichte über ‘Menstruation’ bei Tupaiiden ließen sich nicht bestätigen. Es gibt keinen Beweis, daß Tupaia einen eigentlichen Oestruszyklus besitzt. Wahrscheinlich zeigt Tupaia einen induzierten Follikelsprung und einen rein verhaltensmäßigen Oestruszyklus, ähnlich dem des Kaninchens.6Das allgemeine Verhalten der Tupaiiden wird beschrieben. Die Familie zeigt alle Anpassungen von typisch bodenlebenden zu typisch baumlebenden Arten, verbunden mit entsprechenden Unterschieden in allgemeiner Morphologie, Körpergewicht, Schwanz/Körper-Verhältnis, Futterwahl und allgemeinem Verhalten.7Die Anzeichen von Revierverhalten innerhalb einer Laborpopulation von Tupaia werden untersucht. Tupaia besitzt zwei gutentwickelte Markierungs-Hautfelder (gular und abdominal); wahrscheinlich markieren deren Sekrete neben Harn, Kot und vielleicht Speichel das allgemeine Revier. Die Bedeutung der Reviermarkierung bei Tupaia wird erörtert und mit ähnlichem Verhalten bei Oryctolagus und Petaurus verglichen.8Der Ausdruck ‘Sozialverhalten’ wird definiert. Es gibt keinen überzeugenden Beweis, daß Tupaiiden im Freileben Gruppen von mehr als zwei geschlechtsreifen Tieren bilden; Zeichen ‘sozialer’ Reaktionen im Labor werden erörtert. Arten der T. glis-Gruppe können in Gefangenschaft ♀♀-Paare bilden, aber wohl als Artefakt. Die größte ‘soziale’ Einheit unter natürlichen Bedingungen ist wahrscheinlich die Familie.9Ein grundlegendes Repertoire von 6 Lautäußerungen wird für T. belangeri beschrieben und mit anderen, bisher untersuchten Arten verglichen. T. belangeri und T. glis sind allgemein ähnlich, doch gibt es einige wohl art-spezifische Unterschiede. Sämtliche untersuchte Tupaiiden besitzen einen offensiven, platzenden Schnarr-Laut und eine Reihe von defensiven Schrei-Lauten.10T. belangeri zeigt deutliche Paarbildung, angezeigt durch gemeinsame Benutzung einer Schlafkiste, gemeinsame Ruhestellung in der Mittagszeit, gegenseitiges Maul-Lecken und dorsale Markierung (mit Halsputzen verbunden) des ♀ durch das ♂. Schlechte Paarbildung, definiert durch Seltenheit dieser Verhaltensweisen, ist bei Laborpaaren klar mit schlechten Zuchtergebnissen verbunden.11In Laborpopulationen von Tupaiiden beträgt das Intervall zwischen zwei Geburten 40–50 Tage (Durchschnitt 45 Tage). Das ♀ ist normalerweise gleich nach der Geburt brünstig. Berichte über jahreszeitliche Fortpflanzungsrhythmik bei Labortieren werden als unglaubwürdig betrachtet. Es gibt Hinweise, daß Populationen einiger Tupaia-Arten unter natürlichen Bedingungen eine jahreszeitliche Schwankung der Fortpflanzung zeigen, nicht aber für T. belangeri.12Einiges weist stark darauf hin, daß bei Tupaia die Keimblase erst verzögert, etwa nach der Hälfte der typischen 45-Tage-Tragezeit angeheftet wird. Die extreme Schwankung des zwischengeburtlichen Intervalls (20%), die große Zahl von Keimblasenstadien in einer Stichproben-Sammlung von Tupaia-Gebärmuttern, und die physischen Anforderungen des Säugens und der Eianheftung zusammen mit dem Entwicklungsstand der Jungen bei der Geburt deuten alle darauf hin, daß die eigentliche embryonale Entwicklungsphase kürzer als das Zwischengeburt-Intervall von 45 Tagen ist.13Junge T. belangeri werden in einem gesonderten Nest (‘Kinderstube’) geboren und aufgezogen. Die Eltern schlafen im ‘Elternnest’. Die Kinderstube wird vor der Geburt typischerweise vom ♀ ausgepolstert, das Elternnest wahrscheinlich hauptsächlich vom ♂. Die Wahl des Nestmaterials für die Kinderstube hängt vermutlich mit den thermoregulatorischen Erfordernissen der Jungen zusammen (kleine Blätter werden vernachlässigt). Verschiedene Eltern wählen verschiedene Nistplätze.14Geburten fallen im Labor typischerweise in den Vormittag; die Geburt dauert insgesamt etwa 1 Std. Die Jungen werden normalerweise gleich nach der Geburt gesäugt. Ein Wurf besteht im allgemeinen aus 2–3 Jungen; die durchschnittliche Wurfzahl könnte in der T. belangeri/T. cbinensis-Gruppe unter natürlichen Bedingungen größer sein als die der T. glis-Gruppe. Eine Liste von 6 Symptomen der Geburt wird gegeben (p. 477).15Die Jungen werden in der Kinderstube nur einmal in 48 Std. von der Mutter zum Säugen besucht. Ändert sich das Besuchsintervall, dann normalerweise um 24 Stunden. Solange die Jungen in der Kinderstube sind, wird sie ganz offensichtlich vom ♂ gemieden, abgesehen von Ausnahmefällen, in denen es die Kinderstube gleich wieder verläßt. Die bei jedem Besuch der Mutter abgegebene Milchmenge wurde in typischen Fällen protokolliert.16Junge T. belangeri harnen direkt ins Nest. Das ♀ säubert die Jungen nicht und löst auch kein Harnen und Koten dadurch aus, daß es die Jungen leckte. Das Beschmutzen der Kinderstube hat anscheinend mehrere Funktionen: Die Jungen liegen meist auf den beharnten Blättern; es ist anzunehmen, daß der Harn dazu beiträgt, die Eltern der Kinderstube fern zu halten.17Bei jedem Besuch zeigen die Jungen nach dem Säugen Maul-Lecken an der Mutter. Es gibt jedoch keinen Beweis, daß die Tupaia-Mutter ihren Jungen während der Nestphase Futterbrocken gibt. Anscheinend hat das Maul-Lecken auch in diesem Zusammenhang keine direkte Fütterungsfunktion.18Tupaia-Eltern tragen ihre Jungen nicht (z. B. zu einem neuen Nest) und holen sie auch nicht zum Nest zurück. Die Jungen bleiben normalerweise in der Kinderstube, bis zum ersten Ausflug ungefähr am 33. Tag. In den ersten 3 Tagen danach kehren sie zum Schlafen zur Kinderstube zurück. Nach dieser Zeit (‘Übergangsphase’) schlafen sie mit den Eltern im Elternnest. Während der Übergangsphase zeigen die Jungen häufig Säugen und Maul-Lecken an der Mutter, jedoch scheint die Entwöhnung bis zum 36. Tag abgeschlossen zu sein (unterstützt durch Extrapolation der Milchabgabe-Kurve.) Die Eltern schützen anscheinend ihre Jungen, auch nachdem sie die Kinderstube verlassen haben, nicht direkt.19Junge T. belangeri können eine konstante Körpertemperatur von 37 ± 1 °C (Labortemperatur ungefähr 25 °C) ab erstem Lebenstag einhalten; einen Temperaturabfall unter 33 °C überleben sie gewöhnlich nicht. Die Außentemperatur im natürlichen Gebiet der Tupaiidae fällt normalerweise nicht unter 20 °C; T. belangeri-Junge können im Labor wahrscheinlich bei Temperaturen unter 19 °C nicht am Leben bleiben, auch wenn sie richtig gesäugt werden.20Die Milch von T. belangeri besitzt einen hohen Fett- und einen niederen Kohlenhydrat-Gehalt, was mit dem spezialisierten Mutterverhalten zusammenhängt. Nestjunge haben einen R. Q. von 0,7.21Die Jungen sind in der Kinderstube relativ unbeweglich, äußern aber einen Laut der Erwachsenen (den platzenden Schnarr-Laut), wenn sie gestört werden. Diese Lautäußerung, mit plötzlichem Ausstrecken der Extremitäten verbunden, mag eine Abwehrwirkung gegen Raubtiere haben.22Es gibt einige Anzeichen, daß die Jungen den Säuge-Besuch der Mutter erwarten. Das hätte einen Anpassungswert.23Junge T. belangeri wachsen in der Kinderstube äußerst schnell, was mit dem hohen Eiweißgehalt der Milch erklärt werden kann.24Das Schwanz/Körper-Verhältnis nimmt während der Entwicklung in der Kinderstube zu und erreicht den Wert des Erwachsenen beim Verlassen des Nestes. Die Krallen sind zu dieser Zeit am schärfsten.25Zwischen dem Verlassen der Kinderstube und der Geschlechtsreife entsprechen die Jungen ausgesprochen dem ‘Kindchenschema’, ♂♂ und ♀♀ werden mit etwa 3 Monaten geschlechtsreif. Ab diesem Alter zeigt das ♂ vollen descensus der Hoden und Pigmentierung des Hodensackes. ♀♀ können ab 4 ½ Monaten den ersten Wurf zur Welt bringen.
The locomotor system of the northern smooth-tailed tree shrew (Dendrogale murina), one of the arboreal species of Scandentia, was examined by means of macroscopic anatomy. In this study, we describe the muscular system in the shoulder, forearm, hip and crural regions. The M. deltoideus and the acromion of the scapula were well-developed. The characteristic postscapular fossa was distinguishable in the scapula. The M. teres major and M. triceps brachii possessed large bundles and were attached to the postscapular fossa. In the hindlimb region, the M. biceps femoris was inserted into large area of distal hindlimb. The M. tenuissimus was discernible beneath the M. biceps femoris. We suggest that these findings may contribute to our understanding of arboreal locomotion in this species, and that this may typically represent the arboreal adaptational pattern of the muscular system in the Scandentia.
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