Skull morphological evolution in Malagasy endemic Nesomyinae rodents

Abstract

Madagascar is a large island to the south-east of Africa and in many ways continental in size and ecological complexity. Here we aim to define how skull morphology of an endemic and monophyletic clade of rodents (sub-family Nesomyinae), that show considerable morphological variation, have evolved and how their disparity is characterized in context of the geographical and ecological complexity of the island. We performed a two-dimensional geometric morphometric analysis on 370 dorsal and 399 ventral skull images of 19 species (comprising all nine extant endemic genera) and tested the influence of three ecological parameters (climate, locomotor habitat and nychthemeral cycle) in a phylogenetic context on size and shape. The results indicate that skull shape appears to importantly reflect phylogeny, whereas skull size does not carry a significant phylogenetic signal. Skull shape is significantly influenced by climate while, skull size is not impacted by any of the ecological factors tested, which is controversial to expectations in an insular context. In conclusion, Nesomyinae must have evolved under unusual types of local constraints, preventing this radiation from demonstrating strong ecological release.

A Cybertaxonomic Revision of the “Crocidura pergrisea” Species Complex with a Special Focus on Endemic Rocky Shrews: Crocidura armenica and Crocidura arispa (Soricidae)

“…Free accessibility of the datasets ensures the reliability and repeatability of results. (c) There is a possibility of “analytical” approaches to the assessment of congruence between molecular and morphological data; this can be helpful in the case of ambiguous results when using some analyses, for instance, for a choice between morphological datasets with different levels of a “phylogenetic signal” [ 21 , 34 , 35 ]. In the current study, we implemented two of these: (a) and (b).…”

Phylogenetic evolutionary aspects of the vertebrate skull - an approach for teaching: vertebrate skull

“…Bones and calcified pieces of cartilage are the best-preserved fossil structures (MATA; MATA; TERRAY et al, 2022), and from a single bone it is often possible to reconstruct the general characteristics of a specimen (O'RAHILLY, 1983]. In a limb bone, one can have an idea of the locomotion mode, weight and muscular organization of an individual; for example, the human femur, in general indicates about 40% of the size of the individual and its thickness is proportional to the weight when alive (STANDRING et al, 2008).…”

“…The skull, without much rigor, can be conceptualized as a more or less rigid tissue envelope that, in animals of the clade Craniata, surrounds the brain, the organs of sense and serves as a support for the external organs of the respiratory and digestive apparatus, and defines the animal sense of movement (TORREY, 1978;HIDELBRAND;GOSLOW, 2006;TERRAY et al, 2022).…”

Body mass divergence in sympatric deer species of Pleistocene Crete (Greece)

“…Cases of insular adaptive radiation have been described for vertebrates, invertebrates, and plants (Lomolino et al, 2017). Examples are rarer for mammals and include the murids of Luzon (Jansa et al, 2006), tenrecs (Poux et al, 2008), Malagasy mice (Terray et al, 2022), and lemurs of Madagascar (Martin, 1972;Tattersall, 1982;see, however, Herrera, 2017 in case the requirement of an 'early burst' of phenotypic evolution is included in the definition). The range of morphological disparity that can evolve is, amongst others, phylogenetically and spatio-temporally constrained.…”