Heterochrony in Rodents

Hafner, John C.; Hafner, Mark S.

doi:10.1007/978-1-4899-0795-0_12

Cited by 28 publications

(47 citation statements)

References 33 publications

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“…In the present study, it is proposed that progenetic evolution has occurred independently in two taxa of odontocetes, although it has only been proposed rarely in other mammals (but see also Hafner & Hafner, 1988; Morey, 1994; Raia, Barbera & Conte, 2003). This may reflect a scarcity of progenesis in other mammals, less obvious expressions in animals with direct development than in species that metamorphose between different life stages, and a lack of comparative ontogenetic studies treating other taxa than primates (Shea & Coolidge, 1988; O'Higgins, Chadfield & Jones, 2001; Penin et al.…”

Section: Discussionmentioning

confidence: 66%

Paedomorphosis in two small species of toothed whales (Odontoceti): how and why?

Galatius

2010

Biological Journal of the Linnean Society

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To evaluate and assess the ontogenetic background for paedomorphosis in phocoenids, samples of 144 harbour porpoises, 81 white-beaked dolphins, and 130 Commerson's dolphins were compared in terms of the development of epiphyseal fusion, cranial suture fusion, and ontogeny of cranial shape. Harbour porpoises and Commerson's dolphins terminated growth and development of all investigated traits sooner than white-beaked dolphins, leading to lesser degrees of fusion of skeletal elements and less postnatal allometric development. The latter occurred even though shape in the two paedomorphic species developed at twice the rate relative to the size of white-beaked dolphins. These observations imply that progenetic evolution has occurred convergently in phocoenid and Cephalorhynchus ancestors. The truncated ontogenies allow sexual maturity to be attained earlier and provide a greater reproductive potential. Both species inhabit similar temperate productive habitats and, hence, ecological factors are proposed to have supplied the selection pressures leading to progenesis. Constant prey availability must be a prerequisite for the observed phenomena because frequent food-intake is necessitated by the limited capacity for energy storage and high heat-loss entailed by the resulting small body sizes. Progenesis has rarely been proposed in mammal species. This may reflect rarity or that mammalian expressions of progenesis are less obvious.

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Section: Discussionmentioning

confidence: 66%

Paedomorphosis in two small species of toothed whales (Odontoceti): how and why?

Galatius

2010

Biological Journal of the Linnean Society

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“…Much of the external morphological variation in rodents reflects differences in locomotory mode (Hafner and Hafner 1988). We tested whether locomotory mode determined range sizes by recognizing the following locomotory types: 1) saltatorial/bipedal (hopping), 2) scansorial (terrestrial with climbing and jumping abilities), 3) terrestrial (active at ground level, and with no jumping or climbing ability) and 4) fossorial (subterranean).…”

Section: Determinants Of Range Sizesmentioning

confidence: 99%

Species richness and rarity in European rodents

Kryštufek¹,

Griffiths²

2002

Ecography

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The presence or absence of 77 rodent species was scored within 427 squares of 100×100 miles. The grid encompassed the entirety of Europe west of the Urals and north of the Caucasus, but excluded all offshore islands. Rodent distributional ranges varied between 26 000 and 22 670 000 km2. Very large ranges were uncommon and 53% of species had ranges covering <20% of the study area. Range size showed no correlation with body size, nor did it depend on taxonomic provenance. However, saltatorial rodents appeared to have the largest median ranges and fossorial species the smallest. Species densities varied between 4 and 26 species/grid square, with the highest densities coinciding broadly with the steppe–deciduous forest ecotone. The degree of endemism showed a different geographic pattern from that of species density, with the highest values at lower latitudes. Forty‐nine squares (11% of Europe's surface) identified as species richness and endemism “hot spots” contained >80% of genera and species, their largest contiguous coincidence being in the southern Balkans, the Carpathian Basin, southern Ukraine and cis‐Caucasia.

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“…Evidence for at least some taxa is consistent with this; e.g., bipedal Kangaroo rats, Dipodomys, which inhabit semiarid to arid regions in North America, have longer growth periods and are hypermorphosed in some characters -yet paedomorphosed in others -relative to the ancestral ontogeny (Hafner and Hafner 1988). As noted earlier, the bipedal forms share suites of characters in a characteristic body plan that is today strongly associated with open, arid habitats and has appeared independently in 24 genera in 8 families (Hafner and Hafner 1988). I do not know how many of the 24 instances of parallel evolution involved growth prolongation.…”

Section: Climate In Relation To the Evolution Of Ontogeny Heterochronmentioning

confidence: 67%

“…An example is provided by the enlarged hind-feet of the bipedal, saltatory rodents during times of cooling (section "Climate in Relation to Habitats and Adaptations of Hominins"). If the growth of rodents, the juveniles of which in general have relatively large hind-feet (Hafner and Hafner 1988), is prolonged, a descendant adult with enlarged hind-feet is predicted. Evidence for at least some taxa is consistent with this; e.g., bipedal Kangaroo rats, Dipodomys, which inhabit semiarid to arid regions in North America, have longer growth periods and are hypermorphosed in some characters -yet paedomorphosed in others -relative to the ancestral ontogeny (Hafner and Hafner 1988).…”

Section: Climate In Relation To the Evolution Of Ontogeny Heterochronmentioning

confidence: 99%

“…If the growth of rodents, the juveniles of which in general have relatively large hind-feet (Hafner and Hafner 1988), is prolonged, a descendant adult with enlarged hind-feet is predicted. Evidence for at least some taxa is consistent with this; e.g., bipedal Kangaroo rats, Dipodomys, which inhabit semiarid to arid regions in North America, have longer growth periods and are hypermorphosed in some characters -yet paedomorphosed in others -relative to the ancestral ontogeny (Hafner and Hafner 1988). As noted earlier, the bipedal forms share suites of characters in a characteristic body plan that is today strongly associated with open, arid habitats and has appeared independently in 24 genera in 8 families (Hafner and Hafner 1988).…”

Section: Climate In Relation To the Evolution Of Ontogeny Heterochronmentioning

confidence: 99%

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Paleoenvironments and Hominin Evolution

Vrba

2013

Handbook of Paleoanthropology

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Environmental stimuli have influenced the evolution of hominins and other mammals at the levels of ontogeny, organismal adaptation, and speciation. The review refers to some agreement which has emerged -as well as to persistent debates -on the issue of environmental linkages to hominin adaptation. Current hypotheses which link physical change, adaptation, and speciation in general and in hominins in particular are discussed (including hypotheses on the role of ecological specialization and generalization, the coordinated stasis and variability selection hypotheses, habitat theory, and the turnover pulse hypothesis). Some persistent debates are revisited (such as on the current status of the savanna hypothesis and on whether or not there was mammalian species' turnover in the Turkana Basin during the Plio-Pleistocene). The relation of hominin evolution to the recent finding of several turnover pulses coincident with global cooling trends in the 10 Ma to recent record of all African larger mammals is considered. One example of hypotheses which address issues of environmental stimuli of ontogenetic evolution is the heterochrony pulse hypothesis: the generative properties shared among lineages can result not only in coherence of morphological changes but also in a strongly nonrandom timing of heterochrony events, as diverse lineages respond in parallel by similar kinds of heterochrony to the same environmental changes. The discussion includes cases in hominins and other mammals of evolutionary increase in body size by prolongation of growth and attendant "shuffling" of body proportions including relative increase in brain volume, namely, encephalization.

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Heterochrony in Rodents

Cited by 28 publications

References 33 publications

Paedomorphosis in two small species of toothed whales (Odontoceti): how and why?

Paedomorphosis in two small species of toothed whales (Odontoceti): how and why?

Species richness and rarity in European rodents

Paleoenvironments and Hominin Evolution

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