Geographical Variation of the Skull Morphology of the Common Tree Shrew (Tupaia glis).

Hikida

Motokawa

et al. 2003

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ABSTRACT. Skull size and shape were examined among 14 species of the tree shrews (Tupaia montana, T. picta, T. splendidula, T. mulleri, T. longipes, T. glis, T. javanica, T. minor, T. gracilis, T. dorsalis, T. tana, Dendrogale melanura, D. murina, and Ptilocercus lowii). The bones of face were rostro-caudally longer in T. tana and T. dorsalis, contrasting with T. minor and T. gracilis, D. melanura, D. murina and P. lowii which have smaller facial length ratios. The arbo-terrestrial species (T. longipes and T. glis) were similar to terrestrial species in length ratios of bones of face unlike the other arbo-terrestrial species (T. montana, T. picta, T. splendidula, and T. mulleri). We propose that T. longipes and T. glis have adapted to foraging for termites and ants as have T. tana and T. dorsalis. Additionally small body size in T. javanica may be the result of being isolated in Java. We separated the species into 5 groups from the measurment values of skulls: 1) Terrestrial species; T. tana and T. dorsalis, 2) Arboreal species; T. minor and T. gracilis, 3) Arbo-terrestrial species group 1: T. montana, T. splendidula, T. picta and T. mulleri, and T. javanica, 4) Arbo-terrestrial species group 2: T. glis and T. longipes, 5) Arboreal species of Dendrogale and Ptilocercus. Principal component analysis separated species into 8 clusters as follows: 1) T. tana, 2) T. dorsalis, 3) T. montana, T. splendidula, T. picta and T. mulleri, 4) T. glis and T. longipes, 5) T. javanica, 6) T. minor and T. gracilis, 7) D. melanura and D. murina, and 8) P. lowii. We suggest that these clusters correspond to behavioral strategies and peculiarities observed in foraging, feeding and locomotion in each species.

Section: Discussionmentioning

confidence: 81%

Morphological Adaptation of the Skull for Various Behaviors in the Tree Shrews

Hikida

Motokawa

et al. 2003

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“…The Isthmus of Kra in South Thailand ( Fig. 1) has been considered as distribution barrier in the two variations [1][2][3][4][5]8] and it has been suggested that the grayish-colored northern type and the reddish-colored southern type are zoogeographically split by the Isthmus of Kra. However, the local distribution of the two variations has not been detailed closer to the Isthmus.…”

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confidence: 99%

“…We have not obtained the skin color data of each skull specimen. Although the skull measurement data have also been used in the previous reports [4,5], the specimens from Peninsula Thailand to Thailand-Malaysian border around Isthmus of Kra were rejected in this study, because sympatry and co-distribution of the two types were supposed there. The methods and items of measurement and principal component analysis have been explained in the previous reports [4,5].…”

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confidence: 99%

Sympatric Distribution of the Two Morphological Types of the Common Tree Shrew in Hat-Yai Districts(South Thailand).

Hayashi

Rerkamnuaychoke

et al. 2000

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ABSTRACT. The two color types (grayish northern and reddish southern types) of the common tree shrew (Tupaia glis and Tupaia belangeri) were co-distributed in Hat-Yai region (South Thailand). Although the Isthmus of Kra in South Thailand has been considered as distribution barrier of the two types, the sympatric distribution of both types was confirmed in southern side of the Isthmus. In the principal component analysis, the skull measurement character from Hat-Yai region could also be separated into the northern and southern groups according to the skin color identification of corresponding individuals. We could generally distinguish the common tree shrew into two types by skull morphology as well as external skin color.

“…The nomenclature of measurements were based on the textbook of osteometry [5] and the item abbreviations were arranged in Table 2. We used measurement data of the previous studies [7] in all specimens from the northern side and in most specimens from southern side.…”

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confidence: 99%

Multivariate Analysis in Skull Osteometry of the Common Tree Shrew from Both Sides of the Isthmus of Kra in Southern Thailand.

Nishiumi

Hayashi

et al. 2000

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. The Isthmus of Kra in Southern Thailand consists of a lowland of about 70 km in length. It has been suggested that the Isthmus may sink beneath the sea surface according to the change of level of the sea, and may function as a zoogeographical barrier in land mammals in this region. So, the geographical variation was osteometrically examined in skull of the common tree shrew (Tupaia glis) from the both sides of Isthmus of Kra. The osteometrical examination demonstrated that the skull is larger in southern population than in northern one. In the charts of the principal component analysis, however, the morphological separation between two populations can not be obviously seen in female. While, the results of the discriminant analysis indicated the morphological separation between the two populations. These findings suggest that the zoogeographical barrier of Istmus of Kra may have influence on the osteometrical variation in the common tree shrew, when the Isthmus was covered with sea.-KEY WORDS: common tree shrew, Isthmus of Kra, osteometry, Tupaia belangeri, Tupaia glis.