The Postcranial Morphology of Ptilocercus lowii (Scandentia, Tupaiidae): An Analysis of Primatomorphan and Volitantian Characters

The eutherian orders Scandentia, Primates, Dermoptera, and Chiroptera have been grouped together by many morphologists, using various methods and data sets, into the cohort Archonta. Molecular evidence, however, has supported a clade (called Euarchonta) that includes Scandentia, Primates, and Dermoptera, but not Chiroptera. Within Archonta, some systematists have grouped Dermoptera and Chiroptera in Volitantia, while others have grouped Dermoptera and Primates in Primatomorpha. The order Scandentia includes the single family Tupaiidae, with two subfamilies, Ptilocercinae and Tupaiinae. Ptilocercinae is represented only by Ptilocercus lowii, which has been said to be the taxon most closely approximating the ancestral tupaiid. However, most researchers working on archontan phylogeny typically do not treat the order Scandentia as being polymorphic. They usually use Tupaia to represent Scandentia, despite the fact that Ptilocercus is quite distinct from Tupaia and has been argued to be the more plesiomorphic of the two taxa. In this study, a character analysis was performed on postcranial features that have been used to support the competing Primatomorpha and Volitantia hypotheses. In recognition of the polymorphic nature of Scandentia, taxonomic sampling within Scandentia was increased to include Ptilocercus. The postcranium of Ptilocercus was compared to that of tupaiines, euprimates, plesiadapiforms, dermopterans, and chiropterans. Several character states used to support either Primatomorpha or Volitantia, while not found in Tupaia, were found in Ptilocercus. While these features may have evolved independently in Ptilocercus, it is perhaps more likely that they represent features that first evolved in the ancestral archontan and were then lost in one of the extant orders. This character analysis greatly reduces the supportive evidence for the Primatomorpha hypothesis.     

A new species of Carpolestes (Mammalia,Plesiadapoidea) from the late Paleocene of southern Wyoming: assessing changes in size and shape during the evolution of a key anatomical feature

A new and phylogenetically basal species of Carpolestes, the youngest and most derived genus of the plesiadapoid family Carpolestidae in North America, is described from a late Tiffanian (Ti-5) site in Sweetwater County, Wyoming, USA. Carpolestids differ from closely related plesiadapoid clades in having an enlarged, multicuspidate, blade-like P₄ that is partly convergent on that of multituberculates and other mammals showing plagiaulacoid dental adaptations. With some notable exceptions, the evolutionary history of North American carpolestids is characterized by the progressive development of larger and more elaborate P₄ blades through time. In particular, species of the monophyletic genus Carpolestes differ from species assigned to the earlier and apparently paraphyletic genus Carpodaptes in terms of both the size and shape of their P₄. A geometric morphometric analysis reveals that, with respect to P₄ shape, the closest approximation to the highly derived morphology of Carpolestes is made by Carpodaptes hobackensis, which is one of the smallest known species of Carpodaptes. In contrast, the largest known species of Carpodaptes, Carpodaptes jepseni, has a P₄ that falls within the metric range of variation for species of Carpolestes, yet Carpodaptes jepseni shows a uniquely derived P₄ shape that seems to exclude it from any special phylogenetic relationship with Carpolestes. A phylogenetic analysis based on dental characters reconstructs Carpodaptes hobackensis as the sister group of the Carpolestes clade. Shape seems to have been a more important factor than size during the final transformation of the blade-like P₄ of North American carpolestids.

http://zoobank.org/urn:lsid:zoobank.org:pub:212F9ECC-DA9A-44F8-BE7E-43F3EBAD636A     

Ultrasound use by Sunda colugos offers new insights into the communication of these cryptic mammals

Recent reports of the use of ultrasound for communication by nocturnal mammals have expanded our understanding of behaviour in these animals. The vocal repertoire of colugos has so far only been known to include audible sound. Here, we report the use of ultrasound calls by Sunda colugos (Galeopterus variegatus, order Dermoptera). We recorded one type of call emitted by seven individuals with mean individual frequencies between 37.4 ± 0.6 and 39.2 ± 0.7 kHz during its maximum energy and lasting 28.7 ± 1.6 to 46.9 ± 21.1 ms. Each call showed 3–36 sequential pulses with individual mean interpulse intervals between 423.0 ± 101.4 and 1230.0 ± 315.4 ms. High frequency calls may serve as cryptic anti-predator alarm calls. Our observations suggest that more species of nocturnal mammals may use ultrasound to communicate, and that further studies are needed to determine the occurrence, function and diversity of these calls.