Ontogeny of a Macroevolutionary Phenotype: The External Cheek Pouches of Geomyoid Rodents

Brylski, P.; Hall, Brian K.

doi:10.1111/j.1558-5646.1988.tb04142.x

Cited by 45 publications

(14 citation statements)

References 13 publications

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“…This suggests that although heteromyid cheek pouches are not fully formed at birth (Brylski and Hall 1988), they develop quickly and are fully functional and fully utilized by the time the young leave the burrow.…”

Section: Discussionmentioning

confidence: 99%

Cheek pouch capacities and loading rates of heteromyid rodents

Wall¹,

Longland²,

Pyare³

et al. 1997

Oecologia

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Rodents of the family Heteromyidae are proficient gatherers and hoarders of seeds. A major component of their adaptive specialization for harvesting and transporting seeds is their spacious, fur-lined cheek pouches. Precise measurements of cheek pouch capacities are essential if ecologists are to understand the foraging ecology, possible constraints on locomotion patterns, and competitive relationships of heteromyid rodents. To measure the size of these cheek pouches and the rate at which animals load seeds into their pouches during seed harvest, we attracted 56 individuals representing ten species of heteromyid rodents to bait stations in the field and allowed them to fill their cheek pouches with seeds several times while we observed and timed the events with the aid of night-vision equipment. The largest load taken by each individual was used as an estimate of its cheek pouch capacity. At the end of observations, each subject was captured and its mass and other data gathered. The allometric relationship between cheek pouch capacity and body mass for ten species of heteromyids was significant [pouch capacity (ml) = 0.148 body mass (g), r =0.91, P<0.0001]. The regression coefficient is ≈1.0, which indicates that the volume of the cheek pouches scales in direct proportion to body size. When the data were subdivided into quadrupeds (Perognathus and Chaetodipus) and bipeds (Dipodomys) (n=5 for each), the relationships between pouch capacity and body mass were significant, but the two regressions were not significantly different from each other. When all loads (full and partial) were considered, subjects filled their cheek pouches an average of 93 ± 10% of pouch capacity (n=185). Cheek pouch capacities from published studies of artificially filled pouches of heteromyids in the laboratory averaged about 40% below the field measurements obtained here. The allometric relationship between mean loading rate and body mass was also significant [seeds/s=1.067 bodymass (g), r =0.85,P=0.0011), but when quadrupeds and bipeds were considered separately, the relationships were not significant. Seed densities and bulk densities were used to calculate packing coefficients for seed species, which, when used in conjunction with the allometric relationship between cheek pouch capacity and body size, can be used to estimate the maximum load carried by a heteromyid. Except for the very largest kangaroo rat species, a full pouch load of Indian ricegrass seeds represents less than the daily energy requirements of an active heteromyid.

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Section: Discussionmentioning

confidence: 99%

Cheek pouch capacities and loading rates of heteromyid rodents

Wall¹,

Longland²,

Pyare³

et al. 1997

Oecologia

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show abstract

“…When such a developmental threshold is crossed, a discontinuous change can occur. Empirical examples include internal cheek pouches (Brylski and Hall, ), bone sesamoids (Müller and Streicher, ), or supernumerary digits in mutant mice (Chan et al, ). Simulations of the dynamical behavior of evolving gene regulatory networks indicate that continuous variations are less likely to occur than discontinuous ones (Jaeger et al, ).…”

Section: A Character Based Definition Of Noveltymentioning

confidence: 99%

What is evolutionary novelty? Process versus character based definitions

Peterson

Müller

2013

J Exp Zool Pt B

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With the rise of EvoDevo, the topic of evolutionary novelty has received renewed attention. Indeed, it has been argued that one of the major contributions of EvoDevo to evolutionary theory is the explanation of phenotypic novelty. Despite such assertions, dispute continues over what exactly a novelty is and whether the term applies to a unique type of evolutionary phenomenon or whether it merely has informal meaning. In a recent special issue of J. Exp. Zool. (Mol. Dev. Evol.) dedicated to novelty, a new definition was introduced, linking novelty exclusively with adaptation and developmental constraint. In our commentary, we discuss how defining novelty in this process oriented manner leads to heightened difficulties with the application of the term and the identification of novelties. At the same time it conceals important implications for evolutionary studies. In contrast, we argue for a character based definition that is independent from adaptive necessities and promotes the integration of evolutionary factors not included in the standard theory. The implications of approaching novelty in this manner take the issue beyond definitional debates.

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“…Novel characters derived from ancestral components have been discussed in many preceding communications from both the comparative and developmental perspective (Brylski and Hall 1988;Smith and Hall 1990;Page 2000;Gilbert et al 2001;Shigetani et al 2002;Prum 2005; and see Hall 1999). These studies suggest that the emergence of a novel character is caused by the modification of a developmental process in the evolutionary pathway.…”

Section: Introductionmentioning

confidence: 96%

Origin of the novel chemoreceptor Aesthetasc “Y” in Ostracoda: morphogenetical thresholds and evolutionary innovation

Kaji

Tsukagoshi

2008

Evolution and Development

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The morphology and developmental processes of the two types of ostracod chemoreceptors, the Aesthetasc "Y" and the "Grouped setae," were compared. Cypridoidea and Pontocypridoidea, belonging to Cypridocopina, have a large baseball bat-like seta as an autapomorphic character on the second antenna, whereas most ostracod taxa with plesiomorphic characters bear "Grouped setae" consisting of multiple setae on the second antenna. Their budding positions, morphology, and ontogenetic changes were compared, and our deduction is that the Aesthetasc "Y" originated from "Grouped setae-like" organ in the Paleozoic. The morphogenetic processes in the molting period of these chemoreceptors were compared at the cellular level. The observations suggest that the "Grouped setae" are formed by hypodermal cells and share sheath cells corresponding to those of the Aesthetasc "Y" as a common constraint in the molting process of setae. We conclude that modification of the morphogenetic processes in the molting period of the "Grouped setae" gave rise to the Aesthetasc "Y" as a novel organ in the evolutionary pathway of the Ostracoda.

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Ontogeny of a Macroevolutionary Phenotype: The External Cheek Pouches of Geomyoid Rodents

Cited by 45 publications

References 13 publications

Cheek pouch capacities and loading rates of heteromyid rodents

Cheek pouch capacities and loading rates of heteromyid rodents

What is evolutionary novelty? Process versus character based definitions

Origin of the novel chemoreceptor Aesthetasc “Y” in Ostracoda: morphogenetical thresholds and evolutionary innovation

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