Ecogeography of South-American Rodentia and Lagomorpha (Mammalia, Glires): Roles of size, environment, and geography on skull shape

Magnus, Luíza Z.; Machado, Renata; Cáceres, Nilton C.

doi:10.1016/j.jcz.2018.06.002

Cited by 6 publications

(5 citation statements)

References 51 publications

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“…The morphology of other rodents, including that of the skull, has been similarly demonstrated to be influenced by climate (Monteiro et al 2003;Renaud et al 2005;Pergams and Lawler 2009;Wolf et al 2009;Tabatabaei Yazdi and Adriaens 2011;Cordero and Epps 2012;Alhajeri et al 2020b;Alhajeri et al 2020a). There are many potential explanations for this association between climate and morphology, including the association of climate with resource availability (Wolf et al 2009;Cordero and Epps 2012;Alhajeri 2018;Magnus et al 2018) and climatic adaptation (e.g., to aridity) (Magnus et al 2017;Alhajeri and Steppan 2018;Khajeh et al 2019). More spe-Table 6.…”

Section: Discussionmentioning

confidence: 99%

Skull variation in populations of the Indian gerbil Tatera indica (Gerbillinae, Rodentia) sampled across its broad geographic range

Dashti¹,

Alhaddad²,

Alhajeri³

2022

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Populations of broadly distributed species often exhibit geographic structuring, which is sometimes reflected in phenotype. The monotypic Indian gerbil (Tatera indica) is an example of a widely distributed species, with its range encompassing much of Asia. This study aims to determine if T. indica populations exhibit marked variation in skull morphology—this structure is particularly adaptable and thus could be amenable to show such variation. Furthermore, the potential drivers of skull variation are examined, including the role of climate and geography. To achieve these goals, 21 linear measurements were measured on the skulls of 509 specimens, coming from 111 different localities, across this species wide range. The specimens were then assigned into one of four broad geographic groups (≈ populations) based on their geographic proximity, and the overall and the pairwise differences in the 21 skull measurements among these groups were assessed. Specimens from Pakistan significantly differed from those belonging to the West Iran, East Iran, and India populations, which in turn did not significantly differ from each other. Pairwise bioclimatic and geographic distances between the localities explained a significant, yet small amount of variation in the measurements. Thus, while the Pakistani T. indica population was distinct in skull measurements, both climatic and non-climatic spatial factors seem not to account largely for its distinctiveness (from the other populations).

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Section: Discussionmentioning

confidence: 99%

Skull variation in populations of the Indian gerbil Tatera indica (Gerbillinae, Rodentia) sampled across its broad geographic range

Dashti¹,

Alhaddad²,

Alhajeri³

2022

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“…Over the last decade, CREA has been proposed as a ubiquitous feature of interspecific mammalian (and possibly even vertebrate) cranial evolutionary allometry (Cardini & Polly, 2013, Cardini et al, 2015Bright et al, 2016;Linde-Medina, 2016;Tamagnini, Meloro & Cardini, 2017;Cardini, 2019;G omez & Lois-Milevicich, 2021). The pattern was initially noted by several authors (Robb, 1935;Radinsky, 1985) and recorded in a formal context across a diverse range of mammalian groups, including fruit bats, mongooses, squirrels, antelope, cats, kangaroos, and particularly clear evidence for the pattern has been found in rodents and bovids across multiple studies (Cardini & Polly, 2013;Magnus, Machado & Caceres, 2018;Marcy et al, 2020;Bibi & Tyler, 2022;Rhoda, Haber & Angielczyk, 2023). However, CREA does not appear to be universal.…”

Section: Mechanisms Governing Facial Allometry In Mammalsmentioning

confidence: 97%

“…(2010 a )'s finding that the extinct giant short‐faced bear ( Arctodus simus ) has a similar rostrum length to other bears, but the appearance of a short face in this species is an optical illusion due to it having a much deeper skull. Some research has noted a relatively thinner or shallower face within the context of CREA (Tamagnini et al ., 2017; Magnus et al ., 2018; Weisbecker et al ., 2019; Hennekam et al ., 2020; van der Geer, 2020), and the CREA pattern itself has occasionally been defined as including relative skull flatness (Zelditch & Swiderski, 2023), braincase width (Linde‐Medina, 2016), or width of the zygomatic arches (Weisbecker et al ., 2019) alongside shifts in face length (Table S1). None of these interpretations are necessarily inaccurate, but they highlight the need for a more consistent definition to allow an appropriate interpretation of craniofacial allometric patterns.…”

Section: How Do We Test For Craniofacial Allometry?mentioning

confidence: 99%

Facing the facts: adaptive trade‐offs along body size ranges determine mammalian craniofacial scaling

Mitchell,

Sherratt,

Weisbecker

2023

Biological Reviews

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The mammalian cranium (skull without lower jaw) is representative of mammalian diversity and is thus of particular interest to mammalian biologists across disciplines. One widely retrieved pattern accompanying mammalian cranial diversification is referred to as ‘craniofacial evolutionary allometry’ (CREA). This posits that adults of larger species, in a group of closely related mammals, tend to have relatively longer faces and smaller braincases. However, no process has been officially suggested to explain this pattern, there are many apparent exceptions, and its predictions potentially conflict with well‐established biomechanical principles. Understanding the mechanisms behind CREA and causes for deviations from the pattern therefore has tremendous potential to explain allometry and diversification of the mammalian cranium. Here, we propose an amended framework to characterise the CREA pattern more clearly, in that ‘longer faces’ can arise through several kinds of evolutionary change, including elongation of the rostrum, retraction of the jaw muscles, or a more narrow or shallow skull, which all result in a generalised gracilisation of the facial skeleton with increased size. We define a standardised workflow to test for the presence of the pattern, using allometric shape predictions derived from geometric morphometrics analysis, and apply this to 22 mammalian families including marsupials, rabbits, rodents, bats, carnivores, antelopes, and whales. Our results show that increasing facial gracility with size is common, but not necessarily as ubiquitous as previously suggested. To address the mechanistic basis for this variation, we then review cranial adaptations for harder biting. These dictate that a more gracile cranium in larger species must represent a structural sacrifice in the ability to produce or withstand harder bites, relative to size. This leads us to propose that facial gracilisation in larger species is often a product of bite force allometry and phylogenetic niche conservatism, where more closely related species tend to exhibit more similar feeding ecology and biting behaviours and, therefore, absolute (size‐independent) bite force requirements. Since larger species can produce the same absolute bite forces as smaller species with less effort, we propose that relaxed bite force demands can permit facial gracility in response to bone optimisation and alternative selection pressures. Thus, mammalian facial scaling represents an adaptive by‐product of the shifting importance of selective pressures occurring with increased size. A reverse pattern of facial ‘shortening’ can accordingly also be found, and is retrieved in several cases here, where larger species incorporate novel feeding behaviours involving greater bite forces. We discuss multiple exceptions to a bite force‐mediated influence on facial proportions across mammals which lead us to argue that ecomorphological specialisation of the cranium is likely to be the primary driver of facial scaling patterns, with some developmental constraints as possible secondary factors. A potential for larger species to have a wider range of cranial functions when less constrained by bite force demands might also explain why selection for larger sizes seems to be prevalent in some mammalian clades. The interplay between adaptation and constraint across size ranges thus presents an interesting consideration for a mechanistically grounded investigation of mammalian cranial allometry.

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“…This is similar to Figueirido et al (2010a)’s finding that the extinct giant short-faced bear ( Arctodus simus ) has a similar rostrum length to other bears, but the appearance of a short face in this species is an optical illusion due to having a much deeper skull. Some research has noted a relatively thinner or shallower face within the context of CREA (Tamagnini et al, 2017; Magnus et al, 2018; Weisbecker et al, 2019; Hennekam et al, 2020; van der Geer, 2020), and the CREA pattern itself has occasionally been defined as including relative skull flatness (Zelditch & Swiderski, 2022), braincase width (Linde- Medina, 2016), or width of the zygomatic arches (Weisbecker et al, 2019) alongside shifts in face length (Appendix A; Table S1). None of these interpretations are necessarily inaccurate, but they highlight the need for a more consistent definition to allow an appropriate interpretation of craniofacial allometric patterns.…”

Section: How Do We Test For Craniofacial Allometry?mentioning

confidence: 99%

“…Over the last decade, CREA has been proposed as a ubiquitous feature of interspecific mammalian (and possibly even vertebrate) cranial evolutionary allometry (Cardini & Polly, 2013, Cardini et al, 2015Bright et al, 2016;Linde-Medina, 2016;Tamagnini et al, 2017;Cardini, 2019;Gómez & Lois-Milevicich, 2021). The pattern was initially noted by several authors (Robb, 1935;Radinsky, 1985) and recorded in a formal context across a diverse range of mammalian groups, including fruit bats, mongooses, squirrels, antelope, cats, kangaroos, and particularly clear evidence for the pattern has been found in rodents and bovids across multiple studies (Cardini & Polly, 2013;Magnus et al, 2018;Marcy et al, 2020;Bibi & Tyler, 2022;Rhoda et al, preprint (which was not certified by peer review) is the author/funder. All rights reserved.…”

Section: Introduction (1) Patterns Versus Processes In Mammalian Cran...mentioning

confidence: 97%

Facing the facts: Adaptive trade-offs along body size ranges determine mammalian craniofacial scaling

Mitchell,

Sherratt,

Weisbecker

2023

Preprint

View full text Add to dashboard Cite

The mammalian cranium (skull without lower jaw) is representative of mammalian diversity and is thus of particular interest to mammalian biologists across disciplines. One widely retrieved pattern accompanying mammalian cranial diversification is referred to as “craniofacial evolutionary allometry” (CREA). This posits that “adults of larger species, in a group of closely related mammals, tend to have relatively longer faces and smaller braincases”. However, no process has been officially suggested to explain this pattern, there are many exceptions, and its predictions potentially conflict with well-established biomechanical principles. Understanding the mechanisms behind CREA and causes for deviations from the pattern therefore has tremendous potential to explain allometry and diversification of the mammalian cranium. Here, we propose an amended framework to characterise the CREA pattern more clearly, in that “longer faces” can arise through several kinds of evolutionary change, including elongation of the rostrum, retraction of the jaw muscles, or a more narrow or shallow skull, which all result in a generalised gracilisation of the facial skeleton with increased size. We define a standardised workflow to test for the presence of the pattern, using allometric shape predictions derived from geometric morphometrics analysis, and apply this to 22 mammalian families including marsupials, rabbits, rodents, bats, carnivores, antelope, and whales. Our results show that increasing facial gracility with size is common, but not necessarily as ubiquitous as previously suggested. To address the mechanistic basis for this variation, we then review cranial adaptations for harder biting. These dictate that a more gracile cranium in larger species must represent a sacrifice in the ability to produce or withstand harder bites, relative to size. This leads us to propose that facial gracilisation in larger species is often a product of bite force allometry and phylogenetic niche conservatism, where more closely related species tend to exhibit more similar feeding ecology and biting behaviours and, therefore, absolute (size-independent) bite force requirements. Since larger species can produce the same absolute bite forces as smaller species with less effort, we propose that relaxed bite force demands can permit facial gracility in response to bone optimisation and alternative selection pressures. Thus, mammalian facial scaling represents an adaptive by-product of the shifting importance of selective pressures occurring with increased size. A reverse pattern of facial “shortening” can accordingly also be found, and is retrieved in several cases here, where larger species incorporate novel feeding behaviours involving greater bite forces. We discuss multiple exceptions to a bite force-mediated influence on facial length across mammals which lead us to argue that ecomorphological specialisation of the cranium is likely to be the primary driver of facial scaling patterns, with developmental and/or phylogenetic constraints a secondary factor. A potential for larger species to have a wider range of cranial functions when less constrained by biomechanical demands might also explain why selection for larger sizes seems to be prevalent in some mammalian clades. The interplay between adaptation and constraint across size ranges thus presents an interesting consideration for a mechanistically grounded investigation of mammalian cranial allometry.

show abstract

Ecogeography of South-American Rodentia and Lagomorpha (Mammalia, Glires): Roles of size, environment, and geography on skull shape

Cited by 6 publications

References 51 publications

Skull variation in populations of the Indian gerbil Tatera indica (Gerbillinae, Rodentia) sampled across its broad geographic range

Skull variation in populations of the Indian gerbil Tatera indica (Gerbillinae, Rodentia) sampled across its broad geographic range

Facing the facts: adaptive trade‐offs along body size ranges determine mammalian craniofacial scaling

Facing the facts: Adaptive trade-offs along body size ranges determine mammalian craniofacial scaling

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